U.S. patent application number 11/451465 was filed with the patent office on 2006-10-26 for intelligent station using multiple rf antennae and inventory control system and method incorporating same.
Invention is credited to Donald George Bauer, Edward Raymond Buiel, Richard John Campero, William Joseph Carpenter, Steven Paul Metzler, Richard Eric Nordgren, Paul Brent Rasband, Mark Albert Taylor, Howard E. JR. Wood.
Application Number | 20060238307 11/451465 |
Document ID | / |
Family ID | 26994830 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060238307 |
Kind Code |
A1 |
Bauer; Donald George ; et
al. |
October 26, 2006 |
Intelligent station using multiple RF antennae and inventory
control system and method incorporating same
Abstract
An inventory control system and method that tracks inventories
of items with RFID tags, includes a reader unit and an intelligent
station that tracks RFID tags to determine item information of
items to be inventoried. The reader unit transmits and receives RF
signals. The intelligent station includes a first RF antenna
connected to the reader unit by a first transmission cable through
a first switch, and one or more additional RF antennae connected to
the reader unit by the same first transmission cable through
additional switches. An inventory control processing unit receives
item information from the intelligent stations to update inventory
information regarding the items to be inventoried.
Inventors: |
Bauer; Donald George;
(Laurel, MD) ; Buiel; Edward Raymond; (Mount
Pleasant, SC) ; Campero; Richard John; (Ellicott
City, MD) ; Carpenter; William Joseph; (Sykesville,
MD) ; Metzler; Steven Paul; (Chillicothe, OH)
; Nordgren; Richard Eric; (Daleville, VA) ;
Rasband; Paul Brent; (Frederick, MD) ; Taylor; Mark
Albert; (Columbia, MD) ; Wood; Howard E. JR.;
(Covington, VA) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Family ID: |
26994830 |
Appl. No.: |
11/451465 |
Filed: |
June 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10338892 |
Jan 9, 2003 |
7084769 |
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11451465 |
Jun 13, 2006 |
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60346388 |
Jan 9, 2002 |
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60350023 |
Jan 23, 2002 |
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Current U.S.
Class: |
340/10.1 ;
340/572.7 |
Current CPC
Class: |
G08B 13/2474 20130101;
G06K 7/10336 20130101; G06K 7/10316 20130101; G06K 19/07767
20130101; G06Q 10/087 20130101; G06K 7/10346 20130101; H01Q 1/2216
20130101; G06K 7/10079 20130101; G06K 7/10356 20130101; H01Q 21/28
20130101; G06K 7/0008 20130101; G06K 7/10178 20130101; G06K 17/00
20130101; G07G 1/0045 20130101; H01Q 7/00 20130101 |
Class at
Publication: |
340/010.1 ;
340/572.7 |
International
Class: |
H04Q 5/22 20060101
H04Q005/22 |
Claims
1-96. (canceled)
97. A system for detecting RFID tags comprising: a reader unit that
transmits or receives an RF signal; and a first intelligent station
comprising: a first RF antenna connected to the reader unit by a
first transmission cable through a first switch; and at least a
second RF antenna connected to the reader unit by the first
transmission cable through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals via the first transmission cable.
98. The system of claim 97, wherein the RFID tags comprise one or
more of the group consisting of: active tags, semi-active tags,
passive tags, low frequency tags, high frequency tags, and ultra
high frequency tags.
99. The system of claim 97, wherein the RFID reader and RFID tags
communicate using one or more of the group consisting of: load
modulation, back scatter modulation, amplitude shift keying,
frequency shift keying, and phase shift keying.
100. The system of claim 97, wherein the control signals comprise
one or more of the group consisting of: switch control commands,
switch control query commands, sensor control commands, sensor data
signals, peripheral device control commands, peripheral device data
signals, controller communications, secondary controller
communications.
101. The system of claim 97, wherein the intelligent station
receives DC power through the first transmission cable.
102. The system of claim 97, wherein the intelligent station
detects the presence of a stocking RFID tag or a pushbutton or
keyed input sequence, alerts the intelligent station that the shelf
is completely stocked, and sends a message to a database which
indicates that a current stock level is full or at a target
level.
103. The system of claim 97, wherein the intelligent station
detects the presence of a customer RFID tag, the customer RFID tag
being placed on a shelf where a desired item is in an out-of-stock
condition, wherein the detection of the customer RFID tag results
in one or more actions selected from the group consisting of:
alerting a customer of the condition, generating a rain check,
discounting a price of the item when it is in a subsequent in-stock
condition, and providing information about the item.
104. The system of claim 103, wherein the information is selected
from the group consisting of: being in a stock room, at another
store, and on order.
105. The system of claim 97, wherein the first transmission cable
carries signals with superimposed data other than the RF
signals.
106. The system of claim 105, wherein the first transmission cable
carries a modulated DC signal with DC offset voltage used for data
and control communications.
107. The system of claim 105, wherein the first transmission cable
carries a modulated DC signal without DC offset voltage for data
and control communications.
108. The system of claim 105, wherein the first transmission cable
carries a data or control signal at a frequency different than the
RF signal.
109. The system of claim 105, wherein the first transmission cable
carries a data or a control signal utilizing load modulation or
back scatter modulation.
110. The system of claim 97, wherein a polling scheme is utilized
to determine the order in which the RF antennae are
interrogated.
111. The system of claim 110, wherein the polling scheme is
sequential.
112. The system of claim 110, wherein the polling scheme is altered
based on external events from sensors.
113. The system of claim 97, wherein each of the first switch and
the at least a second switch is uniquely addressable.
114. The system of claim 97, wherein each of the first RF antenna
and the at least a second RF antenna is uniquely addressable.
115. The system of claim 97, further comprising a tuning adjustment
system that automatically performs electronic adjustments of
variable tuning components based on feedback information from the
first RF antenna or the at least a second RF antenna.
116. The system of claim 115, wherein the variable tuning
components comprise one or more voltage controlled capacitors.
117. The system of claim 115, wherein the variable tuning
components comprises a switched capacitor bank.
118. The system of claim 97, wherein the intelligent station
further comprises signal processing circuits to perform at least a
part of the signal processing performed by the reader unit.
119. The system of claim 97, further comprising at least one RF
amplifier device to amplify the RFID signals.
120. The system of claim 97, wherein a common tuning circuit is
used for the first RF antenna and the at least a second RF
antenna.
121. The system of claim 97, wherein the first transmission cable
comprises an RF cable, and wherein a bypass switch is provided
between the RF cable and an intelligent station to either allow an
RF signal to enter the intelligent station, or to prevent an RF
signal from entering the intelligent station.
122. The system of claim 97, further comprising: an inline switch,
wherein the first transmission cable comprises an RF cable, and
wherein the inline switch is configured to either allow the RF
signal to continue along the RF cable past an intelligent station
or to prevent the RF signal from continuing along the RF cable.
123. The system of claim 97, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a series arrangement.
124. The system of claim 97, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a parallel-series arrangement.
125. The system of claim 97, wherein the intelligent station is
connected to or contained within an object from the group
consisting of: a shelf, a closed receptacle, a storage volume, a
room, a closet, a cabinet, a cupboard, a refrigerator, a freezer, a
pegboard, a clothing rack, a trailer, a warehouse, a pallet, a
counter, an enclosure, a rack, a door, a doorway, a portal, a
floor, a floor mat, a ceiling, and a wall.
126. The system of claim 97, further comprising a controller.
127. The system of claim 126, wherein the controller controls the
reader unit.
128. The system of claim 127, wherein the controller determines the
number of antennae contained within the system.
129. The system of claim 127, wherein the controller unit is
operatively connected to the first switch and the at least a second
switch, the controller unit generating a control signal that
selectively operates the first switch and the at least a second
switch.
130. The system of claim 127, wherein signals from the controller
unit are routed to distributed secondary control units that in turn
operate the first switch and the at least a second switch.
131. The system of claim 130, wherein signals from the controller
unit to distributed secondary control units include address
information to determine which switches are selected.
132. The system of claim 97, further comprising one or more passive
antennae associated with one or more of the first RF antenna and at
least a second RF antenna such that the passive antennae are
powered through inductive coupling by the associated RF antennae
when the associated RF antennae are powered.
133. The system of claim 97, further comprising: a data store; and
an inventory control processing unit connected to the data store,
the inventory control processing unit receiving item information
from the intelligent station to update inventory information
regarding the items to be inventoried.
134. The system of claim 133, wherein the intelligent station is
provided with locking devices for access control, the locking
devices controlled by the inventory control processing unit.
135. The system of claim 133, wherein the intelligent station
further comprises a plug-in bar code scanner to scan bar codes and
provide bar coded item information that is correlated and stored
with item information from the RFID tags.
136. The system of claim 97, further comprising a shelf, wherein
the antennae are incorporated into decorative laminate materials
associated with the shelf.
137. The system of claim 136, wherein the laminate materials
containing antennae are applied to one face of a corrugated
paperboard core to form the shelf or a panel for the shelf.
138. The system of claim 97, wherein at least two of the first RF
antenna and the at least a second RF antenna are energized at the
same time.
139. The system of claim 138, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated in phase
with each other.
140. The system of claim 138, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated with a
phase shift between them.
141. The system of claim 140, further comprising: respective RF
cables for each of the at least two antennae, wherein each
respective RF cable has a different length, and wherein the
different RF cable lengths cause the phase shift.
142. The system of claim 140, further comprising: a two-way 90
degree power splitter, wherein the phase shift is created through
the use of the two-way 90 degree power splitter.
143. The system of claim 97, further comprising a peripheral device
other than an antenna.
144. The system of claim 143, wherein the peripheral device is
selected from the group consisting of: a computer terminal, a
display device, a modem, an audio output device, a bar code reader,
a temperature sensor, a shelf-edge price label, a keypad, and a
locking device for enclosed or tethered merchandise.
145. The system of claim 143, wherein the system interrogates each
RF antenna according to a polling scheme.
146. The system of claim 143, wherein the peripheral device
comprises a proximity sensor.
147. The system of claim 146, wherein the proximity sensor is used
for controlling antenna selection.
148. The system of claim 146, wherein the proximity sensor
comprises an infrared sensor or a capacitive sensor.
149. The system of claim 146, wherein the proximity sensor
comprises one of visible light sensors or infrared light
sensors.
150. The system of claim 146, wherein the proximity sensor
comprises a camera.
151. The system of claim 146, wherein the proximity sensor
comprises a proximity type sensor that can detect the movement of
tags or the presence of a shopper.
152. The system of claim 151, wherein the proximity type sensor is
a Hall effect sensor.
153. The system of claim 146, wherein the reading frequency of the
shelf unit increases based on feedback from the proximity
sensor
154. The system of claim 146, wherein the polling scheme is altered
in response to proximity sensor measurements.
155. The system of claim 146, wherein the intelligent station
performs an action in response to the proximity sensor detecting
the presence or movement of a person or object.
156. The system of claim 155, wherein the action is selected from
the group consisting of determining item information and activating
auxiliary displays.
157. The system of claim 143, wherein the peripheral device allows
a user to enter a pushbutton or keyed input sequence.
158. The system of claim 143, wherein the peripheral device
comprises visual or audible indicators on the shelf that are
activated to direct a customer toward the desired items.
159. The system of claim 97, wherein at least one antenna not being
interrogated alter their tuning, the altering causing the at least
one antenna not being interrogated to be substantially non-resonant
at a frequency of the RF signal.
160. The system of claim 159, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by shunting a tuning capacitor.
161. The system of claim 160, wherein the shunting is performed by
a component selected from one or more of the group consisting of: a
FET, a MESFET, and a PIN diode.
162. The system of claim 159, wherein the at least one RF antenna
not being interrogated is altered to be substantially non-resonant
at the frequency of the RF signal by a switching element in the
tuning circuit.
163. The system of claim 162, wherein the switching element is
selected from one or more of the group consisting of: a FET, a
MESFET, and a PIN diode.
164. The system of claim 162, wherein the switching element can
couple and decouple a capacitor within a capacitor bank.
165. The system of claim 159, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by one or more varactors.
166. The system of claim 159, wherein: the at least one antenna not
being interrogated is substantially non-resonant at the frequency
of the RF signal; and an antenna being interrogated is put into a
substantially tuned state.
167. The system of claim 166, wherein each antenna being
interrogated is substantially tuned using one or more of the group
consisting of: a FET, a MESFET, a PIN diode, or a varactor.
168. The system of claim 166, wherein each antenna being
interrogated is substantially tuned through a coupling or
decoupling of a capacitor within a capacitor bank.
169. The system of claim 159, wherein the tuning of the at least
one RFID antennae adjacent to an RFID antenna under interrogation
is altered.
170. The system of claim 169, wherein: a self-test RFID tag is
placed within range of the at least two RFID antennae, the system
detects the self-test RFID tags within adjacent RF antennae, and
the system determines which RF antennae are adjacent.
171. The system of claim 169, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
172. The system of claim 171, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
173. The system of claim 169, wherein the adjacent antennae are
predetermined.
174. The system of claim 97, wherein: a self-test RFID tag is
placed within range of each of the at least two RF antennae; the
system detects the self-test RFID tags; and the system determines
which other RF antenna are adjacent based on the detecting.
175. The system of claim 97, wherein the system determines which RF
antennae are adjacent to each other by detecting RFID tags that are
read by more than one RF antenna.
176. The system of claim 175, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
177. The system of claim 97, wherein GPS information related to the
location of each antenna is used to determine which RF antennae are
adjacent.
178. The system of claim 97, wherein a test determines how much RF
power must be delivered to each connected RF antenna to deliver the
desired power level.
179. The system of claim 178, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
180. The system of claim 178, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
181. The system of claim 97, wherein the desired power level for
each RF antenna is determined based on an antenna type.
182. The system of claim 181, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
183. The system of claim 181, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
184. The system of claim 97, further comprising an environmental
sensor.
185. The system of claim 184, wherein the environmental sensor
comprises a sensor selected from the group consisting of: a
temperature sensor, a humidity sensor, a light sensor, and a weight
sensor.
186. The system of claim 184, wherein an environmental condition is
recorded with the RFID tags located on an intelligent station
during an interrogation.
187. The system of claim 184, wherein the system provides a warning
if an environmental condition is out of a specified limit for
specific products located on an intelligent station.
188. The system of claim 184, wherein a polling scheme is utilized
to determine an order in which the RF antennae are
interrogated.
189. The system of claim 188, wherein the polling scheme is
sequential.
190. The system of claim 188, wherein the polling scheme is event
driven.
191. The system of claim 188, wherein the polling scheme is
determined by the system.
192. The system of claim 188, wherein the polling scheme is altered
in response to the environmental sensor measurements.
193. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; and a first intelligent
station comprising: a first RF antenna connected to the reader unit
by a first transmission cable through a first switch; and at least
a second RF antenna connected to the reader unit by the first
transmission cable through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals via a wireless communications channel.
194. The system of claim 193, wherein the RFID tags comprise one or
more of the group consisting of: active tags, semi-active tags,
passive tags, low frequency tags, high frequency tags, and ultra
high frequency tags.
195. The system of claim 193, wherein the RFID reader and RFID tags
communicate using one or more of the group consisting of: load
modulation, back scatter modulation, amplitude shift keying,
frequency shift keying, and phase shift keying.
196. The system of claim 193, wherein the control signals comprise
one or more of the following: switch control commands, switch
control query commands, sensor control commands, sensor data
signals, peripheral device control commands, peripheral device data
signals, controller communications, secondary controller
communications.
197. The system of claim 193, wherein the intelligent station
detects the presence of a tag or a pushbutton or keyed input
sequence, alerts the intelligent station that the shelf is
completely stocked, and sends a message to a database which
indicates that a current stock level is full or at a target
level.
198. The system of claim 193, wherein the intelligent station
detects the presence of a customer RFID tag, the customer RFID tag
being placed on a shelf where a desired item is in an out-of-stock
condition, wherein the detection of the customer RFID tag results
in one or more actions selected from the group consisting of:
alerting a customer of the condition, generating a rain check,
discounting a price of the item when it is in a subsequent in-stock
condition, and providing information about the item.
199. The system of claim 198, wherein the information is selected
from the group consisting of: being in a stock room, at another
store, and on order.
200. The system of claim 193, wherein a polling scheme is utilized
to determine the order in which the RF antenna are
interrogated.
201. The system of claim 200, wherein the polling scheme is
sequential.
202. The system of claim 200, wherein the polling scheme is altered
based on external events from sensors.
203. The system of claim 193, wherein each of the first switch and
the at least a second switch is uniquely addressable.
204. The system of claim 193, wherein each of the first RF antenna
and the at least a second RF antenna is uniquely addressable.
205. The system of claim 193, further comprising a tuning
adjustment system that automatically performs electronic
adjustments of variable tuning components based on feedback
information from the first RF antenna or the at least a second RF
antenna.
206. The system of claim 205, wherein the variable tuning
components comprise one or more voltage controlled capacitors.
207. The system of claim 205, wherein the variable tuning
components comprises a switched capacitor bank.
208. The system of claim 193, wherein the intelligent station
internally contain signal processing circuits to perform at least a
part of the signal processing otherwise performed by the reader
unit.
209. The system of claim 193, comprising at least one RF amplifier
device to amplify the RFID signals.
210. The system of claim 193, wherein a common tuning circuit is
used for the first RF antenna and the at least a second RF
antenna.
211. The system of claim 193, further comprising: an inline switch,
wherein the first transmission cable comprises an RF cable, and
wherein the inline switch is configured to either allow the RF
signal to continue along the RF cable past an intelligent station
or to prevent the RF signal-from continuing along the RF cable.
212. The system of claim 193, wherein the first transmission cable
comprises and RF cable, and wherein an inline switch is provided to
either allow the RF signal to continue along the RF cable or to
prevent the RF signal from entering the intelligent station.
213. The system of claim 193, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a series arrangement.
214. The system of claim 193, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a parallel-series arrangement.
215. The system of claim 193, wherein the intelligent station is
connected to or contained within an object from the group
consisting of: a shelf, a closed receptacle, a storage volume, a
room, a closet, a cabinet, a cupboard, a refrigerator, a freezer, a
pegboard, a clothing rack, a trailer, a warehouse, a pallet, a
counter, an enclosure, a rack, a door, a doorway, a portal, a
floor, a floor mat, a ceiling, and a wall.
216. The system of claim 193, further comprising a controller.
217. The system of claim 216, wherein the controller controls the
reader unit.
218. The system of claim 217, wherein the controller determines the
number of antennae contained within the system.
219. The system of claim 217, wherein the controller unit is
operatively connected to the first switch and the at least a second
switch, the controller unit generating a control signal that
selectively operates the first switch and the at least a second
switch.
220. The system of claim 217, wherein signals from the controller
unit are routed to distributed secondary control units that in turn
operate the first switch and the at least a second switch.
221. The system of claim 220, wherein signals from the control unit
to distributed secondary control units include address information
to determine which switches are selected.
222. The system of claim 193, further comprising one or more
passive antennae associated with one or more of the first RF
antenna and at least a second RF antenna such that the passive
antennae are powered through inductive coupling by the associated
RF antennae when the associated RF antennae are powered.
223. The system of claim 193, further comprising: a data store; and
an inventory control processing unit connected to the data store,
the inventory control processing unit receiving item information
from the intelligent station to update inventory information
regarding the items to be inventoried.
224. The system of claim 223, wherein the intelligent station is
provided with locking devices for access control, the locking
devices controlled by the inventory control processing unit.
225. The system of claim 223, wherein the intelligent station
further comprises: a plug-in bar code scanner to scan bar codes and
provide bar coded item information that is correlated and stored
with item information from the RFID tags.
226. The system of claim 193, further comprising a shelf, wherein
the antennae are incorporated into decorative laminate materials
associated with the shelf.
227. The system of claim 226, wherein the laminate materials
containing antennae are applied to one face of a corrugated
paperboard core to form the shelf or a panel for the shelf.
228. The system of claim 193, wherein at least two of the first RF
antenna and the at least a second RF antenna are energized at the
same time.
229. The system of claim 228, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated in phase
with each other.
230. The system of claim 228, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated with a
phase shift between them.
231. The system of claim 230, further comprising: respective RF
cables for each of the at least two antennae, wherein each
respective RF cable has a different length, and wherein the
different RF cable lengths cause the phase shift.
232. The system of claim 230, further comprising: a two-way 90
degree power splitter, wherein the phase shift is created through
the use of the two-way 90 degree power splitter.
233. The system of claim 193, further comprising a peripheral
device other than an antenna.
234. The system of claim 233, wherein the peripheral device is
selected from the group consisting of: a computer terminal, a
display device, a modem, an audio output device, a bar code reader,
a temperature sensor, a shelf-edge price label, a keypad, and a
locking device for enclosed or tethered merchandise.
235. The system of claim 233, wherein the system interrogates each
RF antenna according to a polling scheme.
236. The system of claim 233, wherein the peripheral device
comprises a proximity sensor.
237. The system of claim 236, wherein the proximity sensor is used
for controlling antenna selection.
238. The system of claim 236, wherein the proximity sensor
comprises an infrared sensor or a capacitive sensor.
239. The system of claim 236, wherein the proximity sensor
comprises one of: visible light sensors or infrared light
sensors.
240. The system of claim 236, wherein the proximity sensor
comprises a camera.
241. The system of claim 236, wherein the proximity sensor
comprises a proximity type sensor that can detect the movement of
tags or the presence of a shopper.
242. The system of claim 241, wherein the proximity type sensor is
a Hall effect sensor.
243. The system of claim 236, wherein a reading frequency of the
shelf unit increases based on feedback from the proximity
sensor.
244. The system of claim 236, wherein the polling scheme is altered
in response to proximity sensor measurements.
245. The system of claim 236, wherein the intelligent station
performs an action in response to the proximity sensor detecting
the presence or movement of a person or object.
246. The system of claim 245, wherein the action is selected from
the group consisting of determining item information and activating
auxiliary displays.
247. The system of claim 233, wherein the peripheral device allows
a user to enter a pushbutton or keyed input sequence.
248. The system of claim 233, wherein the peripheral device
comprises visual or audible indicators on the shelf that are
activated to direct a customer toward the desired items.
249. The system of claim 193, wherein at least one antenna not
being interrogated alter their tuning, the altering causing the at
least one antenna not being interrogated to be substantially
non-resonant at a frequency of the RF signal.
250. The system of claim 249, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by shunting a tuning capacitor.
251. The system of claim 250, wherein the shunting is performed by
a component selected from one or more of the group consisting of: a
FET, a MESFET, and a PIN diode.
252. The system of claim 249, wherein the at least one RF antenna
not being interrogated is altered to be substantially non-resonant
at the frequency of the RF signal by a switching element in the
tuning circuit.
253. The system of claim 252, wherein the switching element is
selected from one or more of the group consisting of: a FET, a
MESFET, and a PIN diode.
254. The system of claim 252, wherein the switching element can
couple and decouple a capacitor within a capacitor bank.
255. The system of claim 249, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by one or more varactors.
256. The system of claim 249, wherein: the at least one antenna not
being interrogated is substantially non-resonant at the frequency
of the RF signal; and an antenna being interrogated is put into a
substantially tuned state.
257. The system of claim 256, wherein each antenna being
interrogated is substantially tuned using one or more of the group
consisting of: a FET, a MESFET, a: PIN diode, or a varactor.
258. The system of claim 256, wherein each antenna being
interrogated is substantially tuned through a coupling or
decoupling of a capacitor within a capacitor bank.
259. The system of claim 249, wherein the tuning of the at least
one RFID antennae adjacent to an RFID antenna under interrogation
is altered.
260. The system of claim 259, wherein: a self-test RFID tag is
placed within range of the at least two RFID antennae, the system
detects the self-test RFID tags within adjacent RF antenna, and the
system determines which RF antennae are adjacent.
261. The system of claim 259, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
262. The system of claim 261, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
263. The system of claim 259, wherein which of the antennae are
adjacent is predetermined.
264. The system of claim 193, wherein: a self-test RFID tag is
placed within range of each of the at least two RF antennae; the
system detects the self-test RFID tags; and the system determines
which other RF antenna are adjacent based on the detecting.
265. The system of claim 193, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
266. The system of claim 265, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
267. The system of claim 193, wherein GPS information related to
the location of each antenna is used to determine which RF antennae
are adjacent.
268. The system of claim 193, wherein a test determines how much RF
power must be delivered to each connected RF antenna to deliver the
desired power level.
269. The system of claim 268, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
270. The system of claim 268, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
271. The system of claim 193, wherein the desired power level for
each RF antenna is determined based on an antenna type.
272. The system of claim 271, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
273. The system of claim 271, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
274. The system of claim 193, further comprising an environmental
sensor.
275. The system of claim 274, wherein the environmental sensor
comprises a sensor selected from the group consisting of: a
temperature sensor, a humidity sensor, a light sensor, and a weight
sensor.
276. The system of claim 274, wherein an environmental condition is
recorded with the RFID tags located on an intelligent station
during an interrogation.
277. The system of claim 274, wherein the system provides a warning
if an environmental condition is out of a specified limit for
specific products located on an intelligent station.
278. The system of claim 274, wherein a polling scheme is utilized
to determine an order in which the RF antenna are interrogated.
279. The system of claim 278, wherein the polling scheme is
sequential.
280. The system of claim 278, wherein the polling scheme is event
driven.
281. The system of claim 278, wherein the polling scheme is
determined by the system.
282. The system of claim 278, wherein the polling scheme is altered
in response to the environmental sensor measurements.
283. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; and a first intelligent
station comprising: a first RF antenna connected to the reader unit
by a first transmission cable through a first switch; and at least
a second RF antenna connected to the reader unit by the first
transmission cable through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals via a common control channel. The system of claim 283,
wherein the system is composed of an additional intelligent station
comprising: a first RF antenna connected to the reader unit by a
first transmission cable through a first switch; and at least a
second RF antenna connected to the reader unit by the first
transmission cable through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals via the common control channel.
284. The system of claim 283, wherein the common control channel is
wireless.
285. The system of claim 283, wherein the RFID tags comprise one or
more of the group consisting of: active tags, semi-active tags,
passive tags, low frequency tags, high frequency tags, and ultra
high frequency tags.
286. The system of claim 283, wherein the RFID reader and RFID tags
communicate using one or more of the group consisting of: load
modulation, back scatter modulation, amplitude shift keying,
frequency shift keying, and phase shift keying.
287. The system of claim 283, wherein the control signals comprise
one or more of the following: switch control commands, switch
control query commands, sensor control commands, sensor data
signals, peripheral device control commands, peripheral device data
signals, controller communications, secondary controller
communications.
288. The system of claim 283, wherein the common control channel
comprises one of: an Ethernet connection, an RS-485 connection, or
an RS-232 connection.
289. The system of claim 283, wherein the common control channel is
wireless.
290. The system of claim 283, wherein the intelligent station
detects the presence of a stocking RFID tag or a pushbutton or
keyed input sequence, to alert the system that the shelf is stocked
completely and the database is made aware that the current stock
level is the full or target level.
291. The system of claim 283, wherein the intelligent station
detects the presence of a customer RFID tag, the customer RFID tag
being placed on a shelf where a desired item is in an out-of-stock
condition, wherein the detection of the customer RFID tag results
in one or more actions selected from the group consisting of:
alerting a customer of the condition, generating a rain check,
discounting a price of the item when it is in a subsequent in-stock
condition, and providing information about the item.
292. The system of claim 291, wherein the information is selected
from the group consisting of: being in a stock room, at another
store, and on order.
293. The system of claim 283, wherein the intelligent station
receives DC power through the common control channel.
294. The system of claim 283, wherein the intelligent station
receives DC power through the first transmission cable.
295. The system of claim 283, wherein a polling scheme is utilized
to determine the order in which the RF antenna are
interrogated.
296. The system of claim 295, wherein the polling scheme is
sequential.
297. The system of claim 295, wherein the polling scheme is altered
based on external events from sensors.
298. The system of claim 283, wherein each of the first switch, and
the at least a second switch is uniquely addressable.
299. The system of claim 283, wherein each of the first RF antenna
and the at least a second RF antenna is uniquely addressable.
300. The system of claim 283, further comprising a tuning
adjustment system that automatically performs electronic
adjustments of variable tuning components based on feedback
information from the first RF antenna or the at least a second RF
antenna.
301. The system of claim 300, wherein the variable tuning
components comprise one or more voltage controlled capacitors.
302. The system of claim 300, wherein the variable tuning
components comprises a switched capacitor bank.
303. The system of claim 283, wherein the intelligent station
internally contains signal processing circuits to perform at least
a part of the signal processing otherwise performed by the reader
unit.
304. The system of claim 283, comprising at least one RF amplifier
device to amplify the RFID signals.
305. The system of claim 283, wherein the first transmission cable
comprises an RF cable, and wherein a bypass switch is provided
between the RF cable and an intelligent station to either allow an
RF signal to enter the intelligent station, or to prevent an RF
signal from entering the intelligent station.
306. The system of claim 283, further comprising: an inline switch,
wherein the first transmission cable comprises an RF cable, and
wherein the inline switch is configured to either allow the RF
signal to continue along the RF cable past an intelligent station
or to prevent the RF signal from continuing along the RF cable.
307. The system of claim 283, wherein a common tuning circuit is
used for the first RF antenna and the at least a second RF
antenna.
308. The system of claim 283, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a series arrangement.
309. The system of claim 283, wherein the first RF antenna and the
at least a second RF antenna are each associated with a selector
switch and are connected in a parallel-series arrangement.
310. The system of claim 283, wherein the intelligent station is
connected to or contained within an object from the group
consisting of: a shelf, a closed receptacle, a storage volume, a
room, a closet, a cabinet, a cupboard, a refrigerator, a freezer, a
pegboard, a clothing rack, a trailer, a warehouse, a pallet, a
counter, an enclosure, a rack, a door, a doorway, a portal, a
floor, a floor mat, a ceiling, and a wall.
311. The system of claim 283, further comprising a controller.
312. The system of claim 311, wherein the controller controls the
reader unit.
313. The system of claim 312, wherein the controller determines the
number of antennae contained within the system.
314. The system of claim 312, wherein the controller unit is
operatively connected to the first switch and the at least a second
switch, the controller unit generating a control signal that
selectively operates the first switch and the at least a second
switch.
315. The system of claim 312, wherein signals from the controller
unit are routed to distributed secondary control units that in turn
operate the first switch and the at least a second switch.
316. The system of claim 315, wherein signals from the control unit
to distributed secondary control units include address information
to determine which switches are selected.
317. The system of claim 283, further comprising one or more
passive antennae associated with one or more of the first RF
antenna and at least a second RF antenna such that the passive
antennae are powered through inductive coupling by the associated
RF antennae when the associated RF antennae are powered.
318. The system of claim 283, further comprising: a data store; and
an inventory control processing unit connected to the data store,
the inventory control processing unit receiving item information
from the intelligent station to update inventory information
regarding the items to be inventoried.
319. The system of claim 318, wherein the intelligent station is
provided with locking devices for access control, the locking
devices controlled by the inventory control processing unit.
320. The system of claim 318, wherein the intelligent station
further comprises: a plug-in bar code scanner to scan bar codes and
provide bar coded item information that is correlated and stored
with item information from the RFID tags.
321. The system of claim 283, further comprising a shelf, wherein
the antennae are incorporated into decorative laminate materials
associated with the shelf.
322. The system of claim 321, wherein the laminate materials
containing antennae are applied to one face of a corrugated
paperboard core to form the shelf or a panel for the shelf.
323. The system of claim 283, wherein at least two of the first RF
antenna and the at least a second RF antenna are energized at the
same time.
324. The system of claim 323, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated in phase
with each other.
325. The system of claim 323, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated with a
phase shift between them.
326. The system of claim 325, further comprising: respective RF
cables for each of the at least two antennae, wherein each
respective RF cable has a different length, and wherein the
different RF cable lengths cause the phase shift.
327. The system of claim 325, further comprising: a two-way 90
degree power splitter, wherein the phase shift is created through
the use of the two-way 90 degree power splitter.
328. The system of claim 283, further comprising a peripheral
device other than an antenna.
329. The system of claim 328, wherein the peripheral device is
selected from the group consisting of: a computer terminal, a
display device, a modem, an audio output device, a bar code reader,
a temperature sensor, a shelf-edge price label, a keypad, and a
locking device for enclosed or tethered merchandise.
330. The system of claim 328, wherein the system interrogates each
RF antenna according to a polling scheme.
331. The system of claim 328, wherein the peripheral device
comprises a proximity sensor.
332. The system of claim 331, wherein the proximity sensor is used
for controlling antenna selection.
333. The system of claim 331, wherein the proximity sensor
comprises an infrared sensor or a capacitive sensor.
334. The system of claim 331, wherein the proximity sensor
comprises one of: visible light sensors or infrared light
sensors.
335. The system of claim 331, wherein the proximity sensor
comprises a camera.
336. The system of claim 331, wherein the proximity sensor
comprises proximity type sensor that can detect the movement of
tags or the presence of a shopper.
337. The system of claim 336, wherein the proximity type sensor is
a Hall effect sensor.
338. The system of claim 331, wherein a reading frequency of the
shelf unit increases based on feedback from the proximity
sensor.
339. The system of claim 236, wherein the polling scheme is altered
in response to proximity sensor measurements.
340. The system of claim 331, wherein the intelligent station
performs an action in response to the proximity sensor detecting
the presence or movement of a person or object.
341. The system of claim 340, wherein the action is selected from
the group consisting of determining item information and activating
auxiliary displays.
342. The system of claim 328, wherein the peripheral device allows
a user to enter a pushbutton or keyed input sequence.
343. The system of claim 328, wherein the peripheral device
comprises visual or audible indicators on the shelf that are
activated to direct a customer toward the desired items.
344. The system of claim 283, wherein at least one antenna not
being interrogated alter their tuning, the altering causing the at
least one antenna not being interrogated to be substantially
non-resonant at a frequency of the RF signal.
345. The system of claim 344, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by shunting a tuning capacitor.
346. The system of claim 345, wherein the shunting is performed by
a component selected from one or more of the group consisting of: a
FET, a MESFET, and a PIN diode.
347. The system of claim 344, wherein the at least one RF antenna
not being interrogated is altered to be substantially non-resonant
at the frequency of the RF signal by a switching element in the
tuning circuit.
348. The system of claim 347, wherein the switching element is
selected from one or more of the group consisting of: a FET, a
MESFET, and a PIN diode.
349. The system of claim 347, wherein the switching element can
couple and decouple a capacitor within a capacitor bank.
350. The system of claim 344, wherein he at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by one or more varactors.
351. The system of claim 344, wherein: the at least one antenna not
being interrogated is substantially non-resonant at the frequency
of the RF signal; and each antenna being interrogated is put into a
substantially tuned state.
352. The system of claim 351, wherein each antenna being
interrogated is substantially tuned using one or more of the group
consisting of: a FET, a MESFET, a PIN diode, or a varactor.
353. The system of claim 351, wherein each antenna being
interrogated is substantially tuned through a coupling or
decoupling of a capacitor within a capacitor bank.
354. The system of claim 344, wherein the tuning of the at least
one RFID antennae adjacent to an RFID antenna under interrogation
is altered.
355. The system of claim 354, wherein: a self-test RFID tag is
placed within range of the at least two RFID antennae, the system
detects the self-test RFID tags within adjacent RF antenna, and the
system determines which RF antennae are adjacent.
356. The system of claim 354, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
357. The system of claim 356, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
358. The system of claim 354, wherein which of the antennae are
adjacent is predetermined.
359. The system of claim 283, wherein: a self-test RFID tag is
placed within range of each of the at least two RF antennae; the
system detects the self-test RFID tags; and the system determines
which other RF antenna are adjacent based on the detecting.
360. The system of claim 283, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
361. The system of claim 360, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
362. The system of claim 283, wherein GPS information related to
the location of each antenna is used to determine which RF antennae
are adjacent.
363. The system of claim 283, wherein a test determines how much RF
power must be delivered to each connected RF antenna to deliver the
desired power level.
364. The system of claim 363, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
365. The system of claim 363, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
366. The system of claim 283, wherein the desired power level for
each RF antenna is determined based on an antenna type.
367. The system of claim 366, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
368. The system of claim 366, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
369. The system of claim 283, further comprising an environmental
sensor.
370. The system of claim 369, wherein the environmental sensor
comprises a sensor selected from the group consisting of: a
temperature sensor, a humidity sensor, a light sensor, and a weight
sensor.
371. The system of claim 369, wherein an environmental condition is
recorded with the RFID tags located on an intelligent station
during an interrogation.
372. The system of claim 369, wherein the system provides a warning
if an environmental condition is out of a specified limit for
specific products located on an intelligent station.
373. The system of claim 369, wherein a polling scheme is utilized
to determine an order in which the RF antennae are
interrogated.
374. The system of claim 373, wherein the polling scheme is
sequential.
375. The system of claim 373, wherein the polling scheme is event
driven.
376. The system of claim 373, wherein the polling scheme is
determined by the system.
377. The system of claim 373, wherein the polling scheme is altered
in response to the environmental sensor measurements.
378. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; a first RF antenna
connected to the reader unit by a first transmission cable through
a first switch; and at least a second RF antenna connected to the
reader unit by the first transmission cable through at least a
second respective switch, wherein at least two of the first RF
antenna and the at least a second RF antenna are energized at the
same time.
379. The system of claim 328, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated in phase
with each other.
380. The system of claim 328, wherein at least two of the first RF
antenna and the at least a second RF antenna are operated with a
phase shift between them.
381. The system of claim 380, further comprising: respective RF
cables for each of the at least two antennae, wherein each
respective RF cable has a different length, and wherein the
different RF cable lengths cause the phase shift.
382. The system of claim 380, further comprising: a two-way 90
degree power splitter, wherein the phase shift is created through
the use of the two-way 90 degree power splitter.
383. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; and a first intelligent
station comprising: a first RF antenna connected to the reader unit
by a first transmission cable through a first switch; and at least
a second RF antenna connected to the reader unit by the first
transmission cable through at least a second switch; and a control
unit connected to a communications channel and that generates a
control signal for selectively operating the first switch and the
at least a second switch, wherein the control unit can control at
least a peripheral device other than an antenna.
384. The system of claim 383, wherein the peripheral device is
selected from the group consisting of: a computer terminal, a
display device, a modem, an audio output device, a bar code reader,
a temperature sensor, a shelf-edge price label, a keypad, and a
locking device for enclosed or tethered merchandise.
385. The system of claim 383, wherein the system interrogates each
RF antenna according to a polling scheme.
386. The system of claim 383, wherein the peripheral device
comprises a proximity sensor.
387. The system of claim 386, wherein the proximity sensor is used
for controlling antenna selection.
388. The system of claim 386, wherein the proximity sensor
comprises an infrared sensor or a capacitive sensor.
389. The system of claim 386, wherein the proximity sensor
comprises one of: visible light sensors or infrared light
sensors.
390. The system of claim 386, wherein the proximity sensor
comprises a camera.
391. The system of claim 386, wherein the proximity sensor
comprises a proximity type sensor that can detect the movement of
tags or the presence of a shopper.
392. The system of claim 391, wherein the proximity type sensor is
a Hall effect sensor.
393. The system of claim 386, wherein a reading frequency of the
shelf unit increases based on feedback from the proximity
sensor
394. The system of claim 386, wherein the polling scheme is altered
in response to proximity sensor measurements.
395. The system of claim 386, wherein the intelligent station
determines item information or activate auxiliary displays or
perform other actions in response to the proximity sensor detecting
the presence or movement of a person or object.
396. The system of claim 383, wherein the peripheral device allows
a user to enter a pushbutton or keyed input sequence.
397. The system of claim 383, wherein the peripheral device
comprises visual or audible indicators on the shelf that are
activated to direct a customer toward the desired items.
398. A system for detecting RFID tags comprising: at least one
reader unit that transmits or receives an RF signal; and at least
two RF antennae, wherein the at least two RF antennae are coupled
to one or more of the at least one reader units, wherein the tuning
of at least one antenna not being interrogated is altered, the
altering causing the antennae not being interrogated to be
substantially non-resonant at a frequency of the RF signal.
399. The system of claim 398, wherein at least one of the at least
two RF antennae is directly coupled to the at least one reader
unit.
400. The system of claim 398, wherein at least one of the at least
two RF antennae is coupled to the at least one reader unit through
one or more switches.
401. The system of claim 398, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by shunting a tuning capacitor.
402. The system of claim 401, wherein the shunting is performed by
a component selected from one or more of the group consisting of: a
FET, a MESFET, and a PIN diode.
403. The system of claim 398, wherein the at least one RF antenna
not being interrogated is altered to be substantially non-resonant
at the frequency of the RF signal by a switching element in the
tuning circuit.
404. The system of claim 403, wherein the switching element is
selected from one or more of the group consisting of: FET, a
MESFET, and a PIN diode.
405. The system of claim 403, wherein the switching element can
couple and decouple a capacitor within a capacitor bank.
406. The system of claim 398, wherein the at least one antenna not
being interrogated is altered to be substantially non-resonant at
the frequency of the RF signal by one or more varactors.
407. The system of claim 398, wherein: the at least one antenna not
being interrogated is substantially non-resonant at the frequency
of the RF signal; and an antenna being interrogated is put into a
substantially tuned state.
408. The system of claim 407, wherein each antenna being
interrogated is substantially tuned using one or more of the group
consisting of: a FET, a MESFET, a PIN diode, or a varactor.
409. The system of claim 407, wherein each antenna being
interrogated is substantially tuned through a coupling or
decoupling of a capacitor within a capacitor bank.
410. The system of claim 398, wherein the tuning of the at least
one RFID antennae adjacent to an RFID antenna under interrogation
is altered.
411. The system of claim 410, wherein: a self-test RFID tag is
placed within range of the at least two RFID antennae, the system
detects the self-test RFID tags within adjacent RF antenna, and the
system determines which RF antennae are adjacent.
412. The system of claim 410, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
413. The system of claim 412, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
414. The system of claim 410, wherein which of the antennae are
adjacent is predetermined.
415. A system for detecting RFID tags comprising: at least one
reader unit that transmits or receives an RF signal; and at least
two RF antennae, wherein the at least two RF antennae are coupled
to one or more of the at least one reader units, wherein the system
automatically determines whether the RF antennae are adjacent to
each other.
416. The system of claim 415, wherein at least one of the at least
two RF antennae is directly coupled to the at least one reader
unit.
417. The system of claim 415, wherein at least one of the at least
two RF antennae is coupled to the at least one reader unit through
one or more switches.
418. The system of claim 415, wherein the system automatically
determines which of the at least two RF antennae are adjacent to
each other.
419. The system of claim 415, wherein: a self-test RFID tag is
placed within range of each of the at least two RF antennae, the
system detects the self-test RFID tags, and the system determines
which other RF antenna are adjacent based on the detecting.
420. The system of claim 415, wherein the system determines which
RF antennae are adjacent to each other by detecting RFID tags that
are read by more than one RF antenna.
421. The system of claim 420, wherein RF power delivered to the
antennae is increased above a normal operating level to increase a
chance of reading the RFID tags on adjacent antennae.
422. The system of claim 415, wherein GPS information related to
the location of each antenna is used to determine which RF antennae
are adjacent.
423. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; a first RF antenna
connected to the reader unit by a first transmission cable through
a first switch; at least a second RF antenna connected to the
reader unit by the first transmission cable through at least a
second respective switch; a determining unit for determining the
desired RF power to be provided to read each RF antenna connected
to the reader, wherein the system uses the desired RF power when
selectively energizing the RF antennae.
424. The system of claim 423, wherein a test determines how much RF
power must be delivered to each connected RF antenna to deliver the
desired power level.
425. The system of claim 424, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
426. The system of claim 424, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
427. The system of claim 423, wherein the desired power level for
each RF antenna is determined based on an antenna type.
428. The system of claim 427, wherein a power detect sensor
measures the RF power level delivered to the RF antenna.
429. The system of claim 427, wherein at least one self test RFID
tag is used to determine the desired RF power that needs to be
delivered to the RF antenna.
430. A system for detecting RFID tags comprising: one or more
reader units that transmit or receive an RF signal; one or more
intelligent stations comprising: a first RF antenna connected to
the reader unit by a first transmission cable through a first
switch; at least a second RF antenna connected to the reader unit
by the first transmission cable through at least a second switch,
respectively; and an environmental sensor, a memory; wherein the
system records in memory sensor data from the environmental sensor,
and wherein the system records RFID tags on the intelligent station
in the memory.
431. The system of claim 430, wherein the environmental sensor
comprises a sensor selected from the group consisting of: a
temperature sensor, a humidity sensor, a light sensor, and a weight
sensor.
432. The system of claim 430, wherein an environmental condition is
recorded with the RFID tags located on an intelligent station
during an interrogation.
433. The system of claim 430, wherein the system provides a warning
if an environmental condition is out of a specified limit for
specific products located on an intelligent station.
434. The system of claim 430, wherein a polling scheme is utilized
to determine an order in which the RF antennae are
interrogated.
435. The system of claim 434, wherein the polling scheme is
sequential.
436. The system of claim 434, wherein the polling scheme is event
driven.
437. The system of claim 434, wherein the polling scheme is
determined by the system.
438. The system of claim 434, wherein the polling scheme is altered
in response to the environmental sensor measurements.
439. A system for detecting RFID tags comprising: a reader unit
that transmits or receives an RF signal; and a first intelligent
station comprising: a first RF antenna connected to the reader unit
through a first switch; and at least a second RF antenna connected
to the reader unit through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals.
440. A system for detecting RFID tags comprising: a reader unit
that transmits or receives RF signals; and a first intelligent
station comprising: a first RF antenna connected to the reader unit
through a first switch; and at least a second RF antenna connected
to the reader unit through at least a second switch, wherein the
first switch and the at least a second switch receive control
signals, and wherein the intelligent station detects the presence
of a stocking RFID tag or a pushbutton or keyed input sequence,
alerts the intelligent station that the shelf is completely
stocked, and sends a message to a database which indicates that a
current stock level is full or at a target level.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn. 119(e) of provisional application Ser. Nos.
60/346,388, filed Jan. 9, 2002, and 60/350,023, filed on Jan. 23,
2002, the disclosures which are incorporated herein in their
entireties.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
using multiple RF (radio frequency) antennae in an intelligent
station to track items tagged with RFID (radio frequency
identification) tags. More generally, the present invention is
directed to an inventory control method and system that uses the
intelligent station to track and inventory items that are tagged
with RFID tags.
BACKGROUND OF THE INVENTION
[0003] Radio frequency identification (RFID) systems typically use
one or more reader antennae to send radio frequency (RF) signals to
items tagged with RFID tags. The use of such RFID tags to identify
an item or person is well known in the art. In response to the RF
signals from a reader antenna, the RFID tags, when excited, produce
a disturbance in the magnetic field (or electric field) that is
detected by the reader antenna. Typically, such tags are passive
tags that are excited or resonate in response to the RF signal from
a reader antenna when the tags are within the detection range of
the reader antenna. One example of such a RFID system including
details of suitable RF antennae is described in U.S. Pat. No.
6,094,173, the contents of which are incorporated herein in their
entirety. In order to improve the detection range and expand
"coverage" it is known to use coplanar antennae that are out of
phase. One example of such an antenna is provided in U.S. Pat. No.
6,166,706.
[0004] The detection range of the RFID systems is typically limited
by signal strength to short ranges, for example, frequently less
than about one foot for 13.56 MHz systems. Therefore, portable
reader units are moved past a group of tagged items in order to
detect all the tagged items since the tagged items are typically
stored in a space significantly greater than the detection range of
a stationary or fixed single reader antenna. Alternately, a large
reader antenna with sufficient power and range to detect a larger
number of tagged items may be used. However, such an antenna may be
unwieldy and may increase the range of the radiated power beyond
allowable limits. Furthermore, these reader antennae are often
located in stores or other locations were space is at a premium and
it is expensive and inconvenient to use such large reader antennae.
In another possible solution, multiple small antennae may be used
but this configuration may be awkward to set up keeping in mind
that space is often at a premium.
[0005] However, use of multiple antennae (or components) has the
drawback that multiple transmission cables are used to connect a
reader unit to the multiple antennae and/or that the multiple
antennae cannot be individually controlled when they are all
connected by a single transmission cable to the reader unit.
[0006] By way of background, FIG. 1 is a block diagram that
illustrates the basics of a prior art RFID system. A reader unit
100 may typically be connected through RS-232 or similar digital
communication to a terminal 102 such as a computer terminal. The
reader unit 100 is connected by a cable 203 to a reader antenna
200. The reader antenna 200 typically consists of at least a loop
201 and a tuning circuit 202. Although the tuning circuit 202 is
shown as a localized part in FIG. 1, one skilled in the art would
recognize that it might be distributed around the loop 201. The
reader antenna 200 in turn communicates by low power radio waves
105 with one or more RFID tags 106 that are typically associated
with items, objects (animate or inanimate) or persons that are to
be tracked by the RFID system.
[0007] The transmission cable 203 is typically characterized by its
impedance, which in a simplified form, is approximately the square
root of inductance L divided by capacitance C of the transmission
cable. For coaxial cables, the impedance is commonly 50 or 75
ohms.
[0008] Generally, the transmission cable 203, antenna loop 201, and
tuning circuit 202 are connected together in a manner that most
efficiently utilizes the RF power at a desired frequency, which for
a given RFID system using a loop antenna, such as antenna 200, is
typically a "high" frequency such as 13.56 MHz. Another common
"low" frequency that is often used for RFID systems is 125 kHz.
"Ultrahigh" (UHF) frequencies such as 900 MHz or 2.45 GHz within
the RF range are also used with different antenna designs.
[0009] A system using multiple antennae powered by a single reader
unit and using a multiplexer switch to alternate between the
antennae has also been known. Such a system is conceptually
represented in FIG. 2 where two separate antennae 200a and 200b are
connected to a reader and multiplexer unit 101 through respective
transmission cables 203a and 203b. The use of multiple antennae
typically improves the spatial coverage when reading tags, without
requiring more than one reader unit. The main disadvantage of the
arrangement disclosed in FIG. 2 is the need for a separate
transmission cable to each of the antennae. Since space is often at
a premium, the use of these separate cables is a disadvantage
because additional space is needed to install or position each of
these separate cables. This disadvantage is accentuated when more
than two antennae are used with one reader unit since all of these
multiple antennae require separate transmission cables.
SUMMARY OF THE INVENTION
[0010] In one aspect, the present invention provides an intelligent
station that tracks RFID tags, the intelligent station including: a
reader unit that transmits and receives RF signals; a first RF
antenna connected to the reader unit by a first transmission cable
through a first switch; and one or more additional RF antennae
connected to the reader unit by the same first transmission cable
through one or more additional switches. The term "intelligent," as
used herein, means that the system can, through transmission of
radio frequency signals, capture, store, and lookup data, and
monitor unique identifiers associated with trackable items.
[0011] In a further aspect, each of the first and one or more
additional RF antennae includes a loop and a tuning circuit.
[0012] In another aspect of the present invention, the reader unit
includes a tuning circuit for the first and one or more additional
RF antennae, with the tuning circuit connected to the first and one
or more additional RF antennae through the first transmission
cable.
[0013] In another aspect, the present invention includes: a reader
unit that generates and receives RF signals; and a control unit
that is operatively connected to the reader unit and to first and
one or more additional switches, wherein the control unit is
configured to selectively operate the first and one or more
additional switches to connect the reader to the first and one or
more additional RF antennae, respectively. The reader unit and the
control unit may be separate devices or combined in a single
unit.
[0014] In yet another aspect of the present invention, the
intelligent station further includes a second transmission cable
that connects the reader unit to auxiliary RF antenna loops, each
of the auxiliary RF antenna loops arranged proximate to a
corresponding one of the first and one or more additional RF
antennae. The auxiliary antennae receive an unmodulated RF signal
that powers up the tags, which are normally not powered in the
absence of an RF signal. As used herein, "unmodulated RF signal" is
an RF signal without superimposed data. A "modulated RF signal" is
an RF signal carrying superimposed data.
[0015] In a further aspect, the reader unit includes a second
tuning circuit, proximate to the reader unit, that is connected to
the auxiliary RF antenna loops through the second transmission
cable. The second tuning circuit is configured to tune the
auxiliary RF antenna loops.
[0016] In yet another aspect, the present invention provides a
second transmission cable that connects the reader unit to the
first and one or more additional RF antennae through the first and
one or more additional switches, respectively. The reader unit
transmits an unmodulated RF signal to the first and one or more
additional RF antennae through the second transmission cable, and
transmits a modulated RF signal to the first and one or more
additional antennae through the first transmission cable.
[0017] In a further aspect of the present invention, the first
switch is configured to operate in only three states: a first state
such that the first switch only transmits the modulated RF signal
to the first RF antenna; a second state such that the first switch
only transmits the unmodulated RF signal to the first RF antenna;
and a third state such that both the modulated RF signal and the
unmodulated RF signal bypass the first RF antenna. The second
switch includes a multi-pole switch configured to operate in only
three states: a first state such that the second switch only
transmits the modulated RF signal to the associated second RF
antenna; a second state such that the second switch only transmits
the unmodulated RF signal to the second associated RF antenna; and
a third state such that both the modulated RF signal and the
unmodulated RF signal bypass the associated second RF antenna. Each
of the switches can be controlled independently of each other,
thus, for example, the first and second switches may be set to
transmit modulated and unmodulated signals, respectively, at the
same time. In addition, a two-pole switch may be used which is
configured to operate in one of two states (one state being to pass
modulated RF signals to the associated antenna, and the other state
being to pass no signals to the associated antenna).
[0018] In a further aspect, the present invention provides:
additional RF antennae connected to the reader unit through the
same first transmission cable; and additional switches arranged
between the first transmission cable and the additional RF
antennae, respectively.
[0019] In one aspect, an RF transmission cable has a single branch
serving all antennae, that is antennae are connected to a reader
unit through a RF transmission cable in a series arrangement.
[0020] In another aspect, an RF transmission cable has two or more
branches, each serving one or more antennae, That is, antennae are
connected to the reader unit through the RF transmission cable in a
parallel-series arrangement, with each branch on the RF
transmission cable selectable by use of a switch.
[0021] In another aspect, intelligent stations contain RF signal
processing electronics to perform some of the signal processing
otherwise done by the reader.
[0022] In yet another aspect, each of the one or more additional
switches include a PIN type diode.
[0023] In another aspect, the present invention provides an
intelligent inventory control system that uses RFID tags to
determine item information of items to be inventoried, the
intelligent inventory control system including one or more
intelligent stations. Each intelligent station comprises a first RF
antenna connected to the reader unit by a first transmission cable
through a first switch; and one or more additional RF antennae
connected to the reader unit by the same first transmission cable
through respective one or more additional switches. The reader unit
may be located apart from or within one of the intelligent
stations. The inventory control system further includes an
inventory control processing unit, connected to a data store, that
receives item information from the intelligent station to update
inventory information regarding the items to be inventoried.
[0024] In yet another aspect, the present invention provides a
method of inventory control for items tagged with RFID tags, the
method including: providing a plurality of intelligent stations,
each intelligent station including a reader unit that transmits and
receives RF signals, a first RF antenna connected to the reader
unit by a first transmission cable through a first switch; and a
one or more additional RF antennae connected to the reader unit by
the same first transmission cable through respective one or more
additional switches; determining item information of items to be
inventoried by selectively energizing the first and one or more
additional RF antennae of each of the intelligent stations to
determine item information of items that are located on the
respective intelligent stations; and processing the determined item
information to update inventory information of the items to be
inventoried.
[0025] In one aspect, each station has its own reader unit.
However, one reader unit may also serve many stations.
[0026] In a further aspect of the present invention, the inventory
control method includes selectively controlling the first and one
or more additional switches to energize the first and one or more
additional RF antennae and detect item information from items with
RFID tags that are within range of the respective energized one or
more additional RF antennae.
[0027] In a further aspect of the present invention, the inventory
control method includes software control of the RF power level
generated by the reader unit. In a preferred embodiment, testing
would determine how much RF power the reader unit must provide to
achieve optimal results for each connected antenna, which are
positioned at different distances along the RF cable. This
information would be stored, for example, in a look-up table or
other equivalent indexed data storing means. Thereafter during
operation, the power level for each antenna would be set based on
this predetermined level stored in the look-up table, so that
antennae at differing distances along the RF transmission cable may
all operate at essentially equal power.
[0028] In an alternate embodiment, the power provided to each
antenna could also depend on additional factors, for example, on
the type of antenna. Therefore, in the alternate embodiment, both
the distance and type of the antenna could be used to determine and
store the optimal power level for a particular antenna.
[0029] In a further aspect of the present invention, the inventory
control method includes RF amplifier devices, such as RF filter
amplifiers, located periodically along the RF transmission cable
such as in every Nth shelf to boost the RF signal strength.
[0030] In a further aspect of the present invention, the inventory
control method includes updating the determined item information of
items in a data store.
[0031] In a further aspect, the present invention provides that the
inventory control method includes, for each intelligent station,
providing a second transmission cable to connect the reader unit to
one or more auxiliary antenna loops arranged proximate to
respective ones of the first and one or more additional RF
antennae, wherein the reader unit transmits a modulated RF signal
through the first transmission cable and transmits an unmodulated
RF signal through the second transmission cable.
[0032] In yet another aspect, the inventory control method
according to the present invention includes providing, for each
intelligent station, a second transmission cable that connects the
reader unit to the first and one or more additional RF antennae
through first and one or more additional switches, respectively,
wherein the reader unit transmits an unmodulated RF signal to the
first and one or more additional RF antennae through the second
transmission cable, and transmits a modulated RF signal to the
first and one or more additional RF antennae through the first
transmission cable.
[0033] In another aspect the inventory control method of the
present invention provides, for each intelligent station,
configuring the first and one or more additional switches to
operate in one of only three states: a first state that only
transmits a modulated RF signal to a respective one of the first
and one or more additional RF antennae; a second state that only
transmits an unmodulated RF signal to the respective one of the
first and one or more additional RF antennae; and a third state
such that both the modulated RF signal and the unmodulated RF
signal bypass the respective one of the first and one or more
additional RF antennae.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate without
limitation presently preferred embodiments of the invention, and,
together with the general description given above and the detailed
description of the preferred embodiments given below, serve to
explain the principles of the invention.
[0035] FIG. 1 is a block diagram illustrating the basics of a prior
art RFID system.
[0036] FIG. 2 is a block diagram illustrating a prior art RFID
system with multiple antennae connected to a reader unit.
[0037] FIG. 3A is a block diagram illustrating an embodiment of an
inventory control system that uses intelligent stations in
accordance with the present invention.
[0038] FIG. 3B is a block diagram illustrating another embodiment
of an inventory control system that uses intelligent shelves in
accordance with the present invention.
[0039] FIGS. 3C and 3D are flowcharts illustrating processing
performed by the control unit of the inventory control system
according to the present invention.
[0040] FIG. 3E is a block diagram illustrating another embodiment
of an inventory control system that uses intelligent stations in a
parallel-series configuration.
[0041] FIG. 3F is a block diagram illustrating another embodiment
of an inventory control system that uses intelligent stations in
another parallel-series configuration.
[0042] FIG. 3G is a block diagram illustrating a tee switch for use
in a parallel-series configuration.
[0043] FIG. 3H is a block diagram illustrating an inline switch for
use in a parallel-series configuration.
[0044] FIG. 3I is a block diagram illustrating an exemplary method
of carrying RF and digital communications on one cable.
[0045] FIG. 3J is a block diagram illustrating a method of using
switches to minimize undesirable effects of an RF cable extending
past a selected antenna.
[0046] FIG. 4A is a block diagram illustrating one embodiment of
the present invention showing an RFID system with multiple antennae
connected to a reader unit.
[0047] FIG. 4B is a schematic diagram showing a logical switch.
[0048] FIGS. 5 and 6 are block diagrams showing alternate
embodiments of the present invention having multiple antennae.
[0049] FIG. 7 is a block diagram illustrating another embodiment of
the present invention in which two separate transmission cables
transmit modulated and unmodulated RF signals to multiple antennae
each having several loops.
[0050] FIG. 8 is a block diagram illustrating an alternate
embodiment in which the modulated and unmodulated RF systems use
the same antenna loops.
[0051] FIG. 9A is a schematic diagram of an exemplary switch that
may be used with the embodiment disclosed in FIG. 8.
[0052] FIG. 9B is a schematic diagram of another exemplary switch
that may be used with the embodiment disclosed in FIG. 8.
[0053] FIG. 10A is a circuit diagram of a switch using a PIN diode
that may be used with various embodiments of the present
invention.
[0054] FIG. 10B is a circuit diagram showing how an antenna may be
"detuned."
[0055] FIG. 10C is a circuit diagram showing another way that an
antenna may be "detuned."
[0056] FIG. 10D is a circuit diagram showing yet another way that
an antenna may be "detuned."
[0057] FIG. 11A is a diagram illustrating various layouts of reader
antennae on shelves.
[0058] FIG. 11B is a diagram illustrating the use of tags within
shelves.
[0059] FIG. 12 is a diagram illustrating one method of making a
wire antenna.
[0060] FIG. 12A-C are diagrams illustrating alternate ways of
securing the ends of wires on a substrate.
[0061] FIG. 13 is a diagram illustrating an alternate method of
making a wire antenna.
[0062] FIG. 13A is a diagram illustrating various alternate wire
antenna shapes.
[0063] FIG. 14 illustrates another method of making a wire
antenna.
[0064] FIG. 15 is a diagram that illustrates a device and method of
applying foil tape ribbons to a web or planar substrate to form a
foil antenna.
[0065] FIG. 16 is a diagram illustrating another method of
depositing conductive pathways on a substrate to form a foil
antenna.
[0066] FIG. 17 is a diagram illustrating a cross section of an
applicator 2200 for depositing conductive pathways.
[0067] FIG. 18 is diagram that illustrates a method to lay down a
simple rectangular conductive pathway using the apparatus shown in
FIG. 15.
[0068] FIGS. 18A-B illustrate foil strips folded over.
[0069] FIG. 19 shows an embodiment where a conductive trace 2300
being laid down overlaps a previous conductive trace.
[0070] FIG. 20 is a laminated structure containing a foil strip
antenna.
[0071] FIG. 21 is a diagram illustrating the use of a milling
machine to form openings in a substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0072] Unless otherwise specified, "a" or "an" means one or more.
The present invention provides an intelligent inventory control
system including one or more intelligent stations that can detect
RFID tags using multiple antennae. The RFID tags are attached to
items to be detected or tracked. In certain preferred embodiments
discussed herein, the intelligent station system is designated as
an intelligent "shelf" system since the intelligent station system
provided by the present invention is suitable for tracking items on
shelves of stores and warehouses for inventory control or other
tracking purposes. However, it is to be understood that the present
invention is not limited to intelligent shelf systems since one
skilled in the art would recognize its applicability to other uses
such as, for example, tracking items in closed receptacles, other
storage volumes, and particular spaces. Examples of such closed
receptacles or storage volumes include, without limitation, rooms,
closets, cabinets, cupboards, refrigerators, freezers, pegboards,
clothing racks, trailers, warehouses, pallets, counters, and other
similar enclosures, spaces, or racks. It may be used in doors,
doorways and other portals, in floors or floor mats, or in
ceilings. It is also to be understood that the intelligent stations
may be used in orientations other than the horizontal orientation
typically associated with a shelf. For example, the intelligent
shelves may be used in a vertical orientation as, for example, on
the wall of a container, or the back or side area or surface of a
storage volume.
[0073] For use in clothing racks, various embodiments are
envisioned including linear or circular racks. For circular racks
in particular, it is envisioned that two antennas may be used that
are orthogonally disposed in two vertical planes within the center
of the circular rack. The antenna may be driven by a single reader
but the length of their lead-in cables differs, preferably, by 1/4
of the RF wavelength, or alternately, a two-way 90 degree power
splitter is used (e.g. MiniCircuits PSCQ-2-13) to put the two
antennas 90 degrees out of phase. As a consequence the magnetic
field orientation set up by the two antennas "rotates" once each
cycle of the RF wave, so that all RFID tags around the circular
rack may be read.
[0074] For use with clothing racks, another embodiment provides, on
the clothing rack, one or more antenna loops, for example
positioned or hanging at one or both ends of the rack, or
distributed as hangers amidst the clothing. If the antenna loops
are provided in the form of hangers, these may be fabricated by
running conductive wire through narrow (e.g. 1/4''-3/8'' diameter)
thermoplastic tubing, then heat-forming the tubing to create
hanger-shaped antennas. The same method could be used to create
self-supporting antennas in any shape.
[0075] A planar antenna can be limited in its ability to read tags
that are oriented parallel to the magnetic field lines created by
the antenna. The read range may be extended and tag orientation
limitations overcome by providing for an RF-powered antenna
(antenna connected to a reader) and one or more passively coupled
antennae that are not connected directly to the reader. These
passively connected antennae are excited or powered through
inductive coupling with the powered antenna. The passively coupled
antenna will have a magnetic field, preferably, 180 degrees out of
phase with the actively coupled antenna. Thus the orientation of
the resulting magnetic field will oscillate, so that RFID tags in
otherwise unfavorable orientations may still be read. In one
embodiment, the passively coupled antennas could be provided in the
shelf itself, for example, with actively powered antennas in the
front of the shelf and passively coupled antennas in the back of
the shelf, with all antennas being in the plane of the shelf. Other
embodiments include having passively coupled antennae in the
vertical plane at the ends of shelves or backs of shelves. Other
embodiments include using at least one actively powered antenna
within an enclosure such as a box, cabinet, or passageway, with one
or more passively coupled antennae to provide better reading range
or better flexibility in reading tags that are disposed in any
orientation. Other embodiments include having passively coupled
antennae in the vertical plane at the ends of shelves or backs of
shelves. Other embodiments include for a given shelf having
passively coupled antennae in the horizontal plane some distance
above the shelf, preferably just under the next shelf up.
[0076] In a preferred embodiment, the multiple antennae may be put
on a self-supporting shelf or may be embedded into a thin mat that
can be laid on existing store shelves.
[0077] For example, as shown in the block diagram of FIG. 3A,
independent shelf systems 501a, 501b . . . 501n and 502a, 502b . .
. 502n are each provided with multiple antennae 200 that are each
connected to a reader unit 120 by a transmission cable 222. Each
reader unit 120 has a controller or control unit 124 that uses a
control cable 221 in selecting which antenna is active at any time.
Between shelves, the cables 221 and 222 may be interconnected using
connectors 526. While the embodiment disclosed in FIG. 3A shows
that each group of shelves has an RFID system with a reader unit
120 connected to multiple antennae 200, one skilled in the art
would recognize that a single reader unit may be configured to
connect to multiple antennae on more than one shelf that are
located proximate to each other, or each shelf may be configured to
have its own reader unit.
[0078] The block diagram of FIG. 3B shows an alternate embodiment
where each shelf 503a, 503b . . . 503n is provided with multiple
antennae 200. The multiple antennae 200 are each connected to a
reader unit 120 by a transmission cable 222. Each reader unit 120
has a controller 124 to select which antenna is active at any time.
This controller 124 may be a microprocessor. Furthermore, the
shelves may have secondary controllers 125 that co-operate with the
controller 124 to select antennae. The secondary controllers 125
may be microprocessors with sufficient outputs to control all the
antennae within the associated shelf, as well as controlling output
devices 510, such as shelf-edge displays, for displaying
information such as pricing. The output devices 510 could display
information using visible and audible signals as would be
recognized by those skilled in the art. Using secondary controllers
125 may reduce the number of wires required in connectors 526
between shelves.
[0079] The control unit 124 may selectively operate any or all the
switches by sending commands through a digital data communication
cable 221, for example by sending a unique address associated with
each switch, as with would be possible, for example, by using a
Dallas Semiconductor DS2405 "1-Wire.RTM." addressable switch. Each
such addressable switch provides a single output that may be used
for switching a single antenna. Preferably the control unit 124 may
selectively operate any or all the switches by utilizing one or
more secondary control units 125. For example, the secondary
control unit 125 may be a microprocessor such as a Microchip
Technology Incorporated PICmicro.RTM. Microcontroller, which can
provide multiple outputs for switching more than one antenna, such
as all the antennas in proximity to the secondary control unit 125.
The control unit 124 may also be a microprocessor such as a
MicroChip Technology Incorporated PICmicro.RTM. Microcontroller.
Communications between the control unit 124 and the secondary
control unit 125 can be implemented by using digital communication
signals in accordance with well known communication protocols such
as RS-232, RS-485 serial protocols, or Ethernet protocols or Token
Ring networking protocols. Such communications through the
secondary control unit 125 may, in addition to selecting the
desired antennae, also include commands to operate additional
features. Examples of such features include providing displays (for
example, light LED's) proximate to the antennae, displaying
alphanumeric text through appropriate visual displays, or
outputting audible information in the proximity of the
antennae.
[0080] In a preferred embodiment, the intelligent shelf system is
controlled through the electronic network. A controlling system
that controls the intelligent shelf system will send command data
to the control unit 124 via RS-232 or similar protocol. These
commands include but are not limited to instructions for operating
reader unit 120, instructions for operating the antennae switches,
and auxiliary information to be displayed by shelves for example
with lights, visual displays, or sound. The control unit 124 is
programmed to interpret these commands. If a command is intended
for the reader unit 120, the control unit 124 passes that command
to the reader unit 120. Other commands could be for selecting
antennae or displaying information, and these commands will be
processed if necessary by control unit 124 to determine what data
should be passed through digital data communication cable 221 to
the secondary control units 125. Likewise the secondary control
units 125 can pass data back to the controller 124, as can the
reader unit 120. The controller 124 then relays result data back to
the controlling system through the electronic network. The
inventory control processing unit 550, shown in FIGS. 3A and 3B, is
one example of such a controlling system. As discussed further
herein with respect to the intelligent shelf system, the electronic
network and controlling system are used interchangeably to depict
that the intelligent shelf system may be controlled by the
controlling system connected to the intelligent shelf system
through an electronic network.
[0081] At a minimum, control unit 124 must decide whether a command
from the electronic network should be sent to reader 120, or should
be send on the digital communication cable 221. Also, control unit
124 must relay data it receives from the digital communication
cable 221, and from reader unit 120, back to the electronic
network. In the minimum configuration for example, the electronic
network would for example issue a command to read a single antenna.
The control unit 124 would a) set the proper switch for that
antenna, b) activate the reader, c) receive data back from the
reader, d) deactivate the reader, and e) send the data back to the
electronic network.
[0082] FIG. 3C is a flowchart illustrating exemplary processing of
a command signal from a host by the control unit 124. In step 330,
the control unit 124 determines whether there is a command for the
control unit 124 (it may do so by interrogating a memory location
periodically). The control unit 124 then determines in step 332
whether the command was for the reader 120 and, if so, sends the
command to the reader unit 120 in step 334. If not, in step 336,
the control unit 124 decodes the command and sends appropriate
instructions to the secondary controller 125. Thereafter, in step
338, the control unit 124 determines whether a response has been
received from the reader unit 120 if a command had been sent to the
reader in step 334. If a response has been received, then in step
340, the control unit 124 passes the response back to the host.
Thereafter, in step 342, the control unit 124 determines whether a
response has been received from the secondary control unit 125 in
response to the instruction sent in step 336. If a response has
been received from the secondary control unit 125 in step 342, the
response is interpreted by the control unit 124 and sent to the
host in step 344. Thereafter, the processing control returns to
step 330 in which the control unit 124 determines whether there is
another command from the host that needs to be processed.
[0083] The control unit 124 may also perform some management
functions otherwise handled by the electronic network. For example,
the electronic network might issue a command to find a certain
article on the entire shelf system associated with control unit
124. In such a case, the control unit would manage a series of
tasks such as a) determine how many antennae were in its system, b)
set the proper switch for the first antenna, c) activate the
reader, d) receive data back from the reader and save it, e)
deactivate the reader, f) set the proper switch for the next
antenna until all the antennae have been activated, g) activate the
reader until all the antennae have been read. In the preferred
embodiment, when all antennae had been read, the control unit 124
or the electronic network ("host" or the "controlling system")
would analyze its accumulated data and report back only the
location(s) of the desired item.
[0084] FIG. 3D is a flowchart illustrating exemplary management
function processing performed by control unit according to the
present invention. In step 350, the control unit 124 receives a
command from a host application that requests a count of the total
number of antennae controlled by the control unit 124. Therefore,
in step 352, the control unit 124 determines the number of antennae
controlled directly by the control unit 124. Thereafter, in step
354, the control unit 124 issues a command to the secondary control
units 125 to select the next antenna on their list and waits for a
confirmation from the secondary control units 125 in step 356. In
steps 358 and 360, a "read" command is sent to the reader 120 that
awaits and reads the data from the selected antenna and sends the
data to the host application in step 362. Thereafter, the control
unit sends a "standby" command to the reader 120 in step 364 and
determines in step 366 whether all the antennae have been read. If
it is determined that all the antennae have been read in step 366,
the processing is terminated. Otherwise, the process control
returns to step 354 so that the control unit 124 can issue a
command to the secondary control units to select the next antenna
on the list that has not yet been selected.
[0085] An additional advantage of placing the control unit 124
between the electronic network and the reader units is that
different types of readers 120 can be used as desired. The commands
from the electronic network to the control unit may be generic and
not reader-specific. For example the electronic network can send to
the control unit a "read antennas" command. The control unit in
turn can translate this command into the appropriate command syntax
required by each reader unit. Likewise the control unit can receive
the response syntax from the reader unit (which may differ based on
the type of the reader unit), and parse it into a generic response
back to the electronic network. The command and response syntax may
differ for each type of reader unit 120, but the control unit 124
makes this transparent to the electronic network.
[0086] The block diagram of FIG. 3E shows an alternate embodiment
where the controller 124 and reader 120 are contained in shelf
504a. As would be recognized by those skilled in the art, it is
also possible for the controller and reader to be apart from any
shelf. A digital communication cable 221 connects the controller
124 to secondary controllers 125, and RF transmission cable 222
connects the reader 120 to the antennae 200. The controller 124 may
operate a branch switch 527 that selects which of the groups of
shelves (for example 504b-504n, or 505b-505n) will be selected. In
FIG. 3E, the branch switch 527 is used with a "parallel-series"
connection method for the secondary controllers 125 and the
antennae connected to the secondary controller 125. That is,
instead of a controller 124 and reader 120 operating all of the
shelves in single series arrangement, the RF and digital
communication lines are branched (that is, each of the branches are
parallel to each other) before continuing on through shelves
504b-504n in series, and 505b-505n in series. The parallel-series
configuration in FIG. 3E may be advantageous for an aisle of
shelves where typically there are approximately four levels of
shelves (each of which may be connected in parallel), with each
level having perhaps 10-20 shelf units connected in series. In
certain situations a parallel-series configuration may also be
desired from an RF transmission standpoint. For example, if an
aisle has 4 levels of shelves each with 12 shelf units each having
four antennae, the parallel-series configuration connects in
parallel four groups of 48 antennae, while the series-only
configuration would have to connect in series one group of 192
antennae. The RF transmission cable for the series-only
configuration might thus become too long for efficient
operation.
[0087] The block diagram of FIG. 3F shows an alternate embodiment
where the controller 124 and reader 120 are arranged apart from any
shelf. Digital communication cable 221 connects controller 124 to
the secondary controllers 125, and RF transmission cable 222
connects the reader 120 to the antennae 200. The controller 124 or
secondary controller 125 may operate a tee switch 528 that selects
which of the shelves or groups of shelves (for example 506a, or
507a-507b) will be selected. The tee switch 528 may be separate
from or part of a shelf as would be recognized by one skilled in
the art. In FIG. 3F, the tee switch 528 is used with another
"parallel-series" connection arrangement. That is, instead of a
controller 124 and reader 120 operating all shelves in series, the
RF and digital communication lines are branched off (that is,
connected with a multi-drop or "tee" arrangement with each of the
branches arranged in parallel) to shelves or groups of shelves that
are arranged in series. This configuration allows the RF signal to
be switched by the tee switch 528 into a shelf or group of shelves,
or to bypass the shelf or group of shelves. The tee or multi-drop
configuration shown in FIG. 3F may be used to reduce the number of
switching elements through which the RF transmission cable
passes.
[0088] In FIG. 3F the portion 221a of the control cable that
extends beyond shelf 506a, and the portion 222a of the RF cable
extends beyond shelf 506a, are outside of the shelf. However, as
would be recognized by those skilled in the art, these extended
portions of the cables may also be contained within the shelf.
Additional extended control cable portions 221b and additional
extended RF cable portions 222b may be used to connect to more
shelves or groups of shelves. Likewise, additional shelves (not
shown) may be added to groups of shelves, for example to shelves
506a-506b as would be apparent to those skilled in the art.
[0089] FIG. 3G shows an example tee switch 528 on an example shelf
507a. The tee switch contains a switch, for example PIN diode 207c.
A secondary controller 125 associated with shelf 507a may activate
PIN diode 207c to allow the RF signal from RF cable 222a into shelf
507a, where it may be routed through switches 214 to antennae 200.
The RF energy also may continue along RF cable 222b to optional
additional tee switches, and finally to a terminator 215. Thus
typically there may be two parallel loads on the RF cable 222a--the
activated antenna and the terminator 215. A circuit 217, for
example, an isolator circuit that is well known to those skilled in
the art, may be used to match the impedance to reader 120.
[0090] FIG. 3H shows an example inline switch 529 that may be used
on an exemplary shelf 507a. The inline switch contains a switch,
for example, a PIN diode 207d. A secondary controller 125
associated with shelf 507a may activate pin diode 207d to allow the
RF signal from the RF cable 222a to continue along RF cable 222b,
or deactivate PIN diode 207d to prevent the RF signal from
continuing along RF cable 222b. Preferably, tee switch 528 and
inline switch 229 may be used together to either route the RF
signal to the shelf 507a or to RF cable 222b. With the use of one
or more inline switches such as inline switch 529, isolator circuit
217 may not be necessary. However, the inline switch 529 may result
in some RF energy loss.
[0091] FIG. 3I shows an exemplary method of combining the RF and
digital communication on a single cable. The primary controller 124
sends a digital command 250 intended for the intelligent stations.
A converter 251 converts the digital data to a superimposed digital
signal 252 that may be superimposed on the RF cable. For example,
this superimposed digital signal may be at a different frequency
than used by RFID reader 120. This superimposed digital signal may
pass through a filter 253, such as the exemplary inductor 253 shown
in FIG. 31. It then is superimposed onto the RF cable. Another
filter 254 may be used to block the superimposed signal from
reaching the RFID reader 120.
[0092] The combined RF and digital signals pass down cable 222a to
one or more intelligent stations 261, 262, 263, etc. (only 261 and
262 shown in FIG. 3I). Upon reaching exemplary intelligent station
261, the combined signal may pass through another filter 255, such
as an inductor sized to block the RF signals from the RFID reader.
The superimposed digital communication passes through filter 255
and into a receiver circuit 256 that retrieves the digital
information and passes it to secondary controller 125, and
optionally to additional secondary controllers 260.
[0093] The secondary controller 125 may send information back to
the primary controller 124 through a transmitter circuit 257, for
example operating at a frequency other than the RF frequency of
reader 120, and optionally at a different frequency than used for
communicating from the primary controller (or control unit) 124 to
the secondary controller (or control unit) 125. Such information
may be received by receiver circuitry 258, converted to appropriate
digital signals 259 and returned to the primary controller 124.
[0094] A variation on the method for digital communication between
the primary controller 124 and secondary controller 125 is to send
digital communications from the primary controller 124 as a series
of pulses at two or more DC voltages. Preferably, both voltages are
high enough to power any circuitry associated with the secondary
controller 125, peripherals 510, etc that require DC power. These
voltages may be sent from digital transmitter circuit 251, and
received by receiver circuitry 256, which could be a simple voltage
comparator circuit. Communication from the secondary controller 125
back to the primary controller may be provided by having the
digital transmit circuitry 257 provide two different levels of
current draw or load on the communications cable, for example by
switching in and out a transistor feeding a resistor. Such
variations in the current draw would then be sensed by the receiver
circuit 258 and converted into digital data for the primary
controller 124.
[0095] FIG. 3J illustrates an exemplary method using switches to
minimize the undesirable effects of an RF cable extending past a
selected antenna. It will be understood from the preceding
descriptions that switches may be controlled by the intelligent
station system through use of secondary controllers (or control
unit). FIG. 3J shows a reader unit 370 connected to a series of
antennas 371-377. The series of antennae are also denoted as
1.sup.st, 2.sup.nd, Nth, etc. Each antenna has associated with it
circuitry 380. The circuitry may include a coaxial cable 381
carrying the RF signal. An RF-carrying center conductor may be
shorted to the coaxial shield by shunt switch 382, or connected to
tuning circuitry and thereafter the antenna 371 through a select
switch 383. The coaxial shield is electrically continuous as
denoted by line 384. The coaxial shield would typically be
grounded. The coaxial center conductor is likewise continuous.
[0096] The distance between successive antennae is, preferably, an
integer submultiple of a quarter-wavelength of the RF signal. For
example, an RF signal at 13.56 MHz travelling through standard
coaxial cable with polyethylene dielectric has a quarter wavelength
of approximately 12 feet. Thus, as shown in FIG. 3J, a one-foot
coaxial length between antennae could be used to provide a
one-twelve submultiple of a quarter wavelength spacing. Other
integer submultiples are possible, for example a 1.5-foot coaxial
length between antennae could be used to provide a one-eighth
submultiple.
[0097] To illustrate the method, the Nth antenna 373 could be
selected by closing select switch 385 to direct the RF signal to
antenna 373. Also, shunt switch 386 is closed to short the RF
signal to the coaxial shield at antenna 375, which is located a
quarter wavelength further along the RF cable. A short circuit at
one-quarter wavelength distance along the RF cable is seen as an
infinite impedance, and minimizes the adverse effects of the RF
cable extension past the selected antenna. At the end of the series
of antennae, there may optionally be additional shunting switches
as denoted by 378 and 379.
[0098] In the preferred embodiments, the intelligent station system
is modular, using inexpensive components to handle data from the
multiple antennae. Multiple antennae within a shelf may be
activated in sequence or, optionally, with phase delays to enhance
their effectiveness as is within the abilities of those skilled in
the art.
[0099] With reference to the figures, FIG. 4A is a block diagram
illustrating one embodiment of the present invention that shows an
RFID system with multiple antennae 200, 210 (only two shown for
convenience) connected to a reader unit 120. Therefore, the RFID
system disclosed herein could be used to implement the intelligent
stations 501a-n or 502a-n shown in FIG. 3A. FIG. 4A is not intended
to limit the present invention since those skilled in the art would
recognize various modifications, alternatives, and variations
thereof. Furthermore, one skilled in the art would recognize that
the present invention, and its construction and method of operation
would apply to transmissions and detection at other frequencies
also as long as power and regulatory requirements are satisfied.
The RFID system may comprise a single shelf or the multiple
antennae may be arranged on proximate shelves and connected to a
single reader unit using connectors, for e.g., co-axial or other
connection means. As shown in FIG. 4A, a single RF transmission
cable 222 is used to connect to both the antennae 200 and 210. The
transmission cable 222 terminates in a conventional terminator 215.
The reader unit 120 is associated with a control unit 124 but does
not have a multiplexer. Instead the controller 124 is designed to
control switches 204 and 214 located at the antennae 200 and 210,
respectively. The control unit 124 may also communicate with
secondary control units 125, for example, located proximate to the
antennae. The secondary control unit 125 may include
microprocessors or addressable devices that may cooperate with
control unit 124 in selecting the antennae.
[0100] In one embodiment, the switches 204 and 214 are connected to
the control unit 124 by a separate cable 221. Those skilled in the
art would recognize that other means, including wireless means, or
different frequency signals superimposed on the RF signal carried
on the cable 222, may be used to connect the control unit 124 to
the switches 204 and 214. The switches 204, 214 are controlled so
that at any time, only one of the antennae 200, 210 is connected to
the reader unit 120 through the cable 222.
[0101] FIG. 4B is a schematic diagram showing a logical switch 204
that toggles between an open (dotted line) and a closed position,
which powers the antenna. Such a logical switch may be used with
the embodiment discussed with respect to FIG. 4A.
[0102] FIG. 5 is another embodiment of the present invention that
is similar to the embodiment discussed above with respect to FIG.
4A, except that the antennae 200 are all identical, as shown in
FIG. 5. Therefore, the tuning circuits 202 may all be identical,
which simplifies antenna fabrication. Therefore, the reader unit
120 is connected by transmission cable 222 and switches 204 and 214
to respective multiple identical antennae 200.
[0103] FIG. 6 is block diagram of an alternate embodiment that
shows a benefit when the multiple antennae 200 are identical.
Portions of the tuning circuitry 202 may be moved back to a common
tuning circuit 213 at or proximate the reader unit 120 itself.
Therefore, the reader unit 120 is connected to the multiple
antennae 200 through a common tuning circuit 213 that is provided
at the reader unit 120. As would be recognized by those skilled in
the art, a main tuning circuit 202 or 212 may still be provided for
each antenna 200.
[0104] FIG. 7 is a block diagram illustrating another embodiment of
the present invention in which two separate transmission cables 222
and 230 transmit modulated and unmodulated RF signals,
respectively, to multiple antenna configurations each of which
include antenna loops 201 and 231. Associated with the reader unit
130 is a control unit 134. The reader unit 130 is designed so that
a RF signal can be split to allow an unmodulated RF signal to be
transmitted through a separate cable 230 and through a tuning
circuit 232 into antenna loops 231 that are associated with the RF
antennae 201. Each of the RF antennae 201 is associated with
respective antenna loops 231. As before, the reader unit 130 also
generates a modulated RF signal that is transmitted through the
tuning circuit 212 and the transmission cable 222 to the multiple
antennae 201. Respective switches 204 and 214 connect the
respective antennae 201 to the transmission cable 222 and also
connect the respective antenna loops 231 to the transmission cable
230.
[0105] In one embodiment, the unmodulated RF system, including the
tuning circuit 232, the cable 230, and the antenna loops 231 may
all be powered continuously. In contrast, the reader antenna data
loops 201 may only be turned on one at a time by suitably
controlling the switches 204 and 214. Because the loops 231 can be
powered continuously, there is no start-up time required for RFID
tags to charge up during data transfer. Such a system could
advantageously be used in situations where the RFID tags need to be
frequently read. Furthermore, this embodiment also allows handheld
reader units to read the tags at any time because the tags are
always powered in view of the continuous powering of the
unmodulated RF system. The unmodulated cable 230 has a terminator
216 at the end of the cable 230. In this context, it should be
understood that the term "continuous" power may include a
percentage duty cycle if required by legal or other limits.
Alternatively, the unmodulated RF system can be activated just
prior to activating the modulated RF system for each antenna.
[0106] FIG. 8 is another embodiment that is similar to the
embodiment discussed above with respect to FIG. 7. In this
embodiment, the modulated RF signal through cable 222 and the
unmodulated RF signal through cable 230 are routed through the same
antennae 201. The switches 204 and 214 are preferably configured so
that the modulated RF signal 222, or unmodulated RF signal 230, or
neither signal, is routed into a given antenna 201. That is, the
switches 204 and 214 are designed so that they can only operate in
three states: (I) a first state in which only the modulated RF
signal is transmitted to an antenna 201; (II) a second state in
which only the unmodulated RF signal is transmitted to the antenna
201; and (III) a third state in which both the modulated RF signal
and the unmodulated RF signal bypass the antenna 201.
[0107] Such a switching operation can be implemented with groups of
single or multi-pole RF switches. In operation, this embodiment
allows for an antenna 201 to be inactive until just before its turn
to be polled. At that point, the unmodulated RF signal can be
switched into the antenna 201 through the tuning circuit 232, the
transmission cable 230 and the appropriate switch 204, 214 to "warm
up" the nearby RFID tags. Thereafter, the modulated RF signal is
switched into that antenna 201 through the tuning circuit 212, the
cable 222, and the appropriate switch 204, 214 to efficiently
acquire data from the RFID tags that have just been warmed up.
[0108] FIG. 9A is a simplified schematic diagram of a switch 205
that may be used, for example, with the embodiment discussed with
respect to FIG. 8. FIG. 9A is not intended to limit the present
invention since those skilled in the art would recognize various
modifications, variations, and alternatives thereon. When switch
205A is thrown to the left to connect one pole of antenna loop 201
onto the center conductor of modulated RF signal coaxial cable 222,
with the other pole connected to the shield of the same cable, the
modulated RF signal is transmitted to the antenna 201. If switch
205A is thrown to the right, the signal in the modulated cable 222
continues on to another antenna. Switch 205B is shown thrown to the
right, so that the unmodulated RF signal continues on toward
another antenna. If switch 205B is thrown to the left, the
unmodulated RF signal will be passed through the antenna 201. If
both switches A and B are thrown to the right, both signals will
bypass the antenna which will be completely inactive. Switch 205 is
designed so that switches 205A and 205B cannot both be thrown to
the left.
[0109] FIG. 9B is a simplified schematic diagram of an alternative
switch 205C that may be used, for example, with the embodiment
discussed with respect to FIG. 8. This diagram shows that the
common (or ground) wire may not need to be switched, and that a
switch may be branched off of the RF cable instead of being
directly inline with the cable. When switch 205C is thrown to the
left, it connects one pole of antenna loop 201 onto the center
conductor of modulated RF signal coaxial cable 222, with the other
pole connected to the shield of the same cable, so the modulated RF
signal is transmitted to the antenna 201. If switch 205C is thrown
to the center, the unmodulated RF signal 230 will be passed through
the antenna 201. If switch 205C is thrown to the right, neither RF
signal will enter the antenna which will be completely inactive.
Note in the case of switch 205C that the RF signals also continue
down their respective cables, past the antenna 201, regardless of
the switch 205C setting.
[0110] FIG. 10A shows a circuit diagram for a RF switch that may be
used, for example, as switch 204 or 214 discussed earlier herein
with respect to various embodiments of the present invention. FIG.
10A is not intended to limit the present invention since those
skilled in the art would recognize various modifications,
variations, and alternatives thereof. As shown, the RF switch
utilizes a PIN (P-type, I-type, N-type) diode 207 (for example,
Microsemi part number 900-6228) which acts in a similar way to a
regular PN diode except that it is able to block a RF signal when
the switch contact is open. When the switch contact is closed, the
PIN diode 207 becomes forward biased and conducts the RF signal.
The control signal used to select the antenna may also be
superimposed (not shown) on the RF signal that is used to read the
RFID tags. Such a control signal could be separated from the RF
signal by a band pass filter and then go on to an addressable
switch, which selectively activates the RF switch utilizing a PIN
diode. In FIG. 10A, the control signal is provided on separate
wiring instead of using the RF signal cable. While superimposing
the control signal on the RF signal cable may require fewer
conductors and/or connectors between antennae or between
intelligent stations, it requires additional electronic components
to separate the signals at each antenna. Thus it may be more
efficient to have separate wiring for the control signal.
[0111] FIG. 10B illustrates a circuit diagram for detuning an
antenna so that, if the antenna is not selected for activation, it
will not resonate when a nearby antenna is selected. If the antenna
is not selected, then the PIN diode 207a shorts out tuning
capacitor 211a, and thereby changes the frequency of the antenna so
that it will not be active at the frequency used to operate the
antenna to read the RFID tags.
[0112] Using a PIN diode such as 207a to short out tuning
capacitors and detune an antenna means that PIN diode 207a may be
run under power for significant lengths of time. This may generate
heat and waste power. Therefore the system may be designed to only
detune antennae that are immediately adjacent to the antenna
currently being read. Which antennae are adjacent may be determined
by several methods. For example, this may be specified during
design, or found by observation after assembly, or may be
determined with the RFID reader during operation as described
further herein.
[0113] FIG. 10C shows another circuit diagram where a PIN diode
207b is used to tune the loop. Here the loop is in tune when PIN
diode 207b is energized. Therefore, the PIN diode 207b is not
required to remain on while the loop is not being read. This may
save power and reduce heat generation.
[0114] While the examples here include use of PIN diodes for the
switching and detuning functions, other electronic components such
as, for example, FET (field effect transistor) or MESFET
(metal-semiconductor FET) devices may also be used as would be
recognized by those skilled in the art.
[0115] FIG. 10D shows another circuit diagram where a switch, for
example field effect transistor (FET) 208, within the resonant part
of the circuit is used to detune the loop. Here the loop is in tune
when FET 208 is deenergized, and detuned when FET 208 is energized.
In the energized state, the FET 208 draws little power.
Furthermore, in this position within the circuit, when the FET 208
is energized it sufficiently detunes the loop antenna so that RF
tends not to enter the tuning circuit. Therefore it may not be
necessary to provide a separate FET or PIN diode to select the
loop.
[0116] FIG. 10B illustrates one aspect of the present invention
that variable capacitors (for example, variable capacitors 211a-c
shown in FIG. 10B) may be used to tune the antenna, that is, to
cause it to resonate at the same frequency as the RF signal from a
reader unit. As the surroundings of the antenna may influence the
tuning, any structure enclosing the tuning circuit is preferably
designed to keep the adjustable components accessible from the
outside, for example, by locating them at an edge of the structure
(such as a shelf edge) or by providing access holes for tuning
devices (such as servo-controlled screwdrivers).
[0117] Furthermore, since tuning an antenna can be a trial and
error process and time-consuming, it is desirable to permit the
tuning to be done automatically. According to one aspect of the
present invention, this is accomplished by providing an automatic
tuning unit (not shown) that would temporarily attach
computer-controlled servo-driven screwdrivers to adjustment screws
associated with the adjustable capacitors. To achieve optimal
tuning, the automatic tuning unit (which may include a computer or
other suitably programmed microprocessor) would receive feedback
from a conductive connection to the antenna being tuned, or from an
RFID reader that would detect which tags were identified from an
array of tags in a predetermined or known spatial (preferably two
or three-dimensional) arrangement. The tuning unit, based on a set
of rules, experimentally developed or developed from experience,
would manipulate the adjustment screws to achieve optimal tuning.
Alternatively, the controller or secondary controller may adjust
the tuning of each antenna by electronic adjustment, for example by
remotely setting adjustable voltage-controlled capacitors within
the tuning circuit. This method would minimize the need for using
mechanical or servo controlled adjustments for tuning.
Voltage-controlled capacitors in the tuning circuit could also be
used to detune antennae so they would not resonate when they were
not selected for reading.
[0118] In one embodiment, RFID tags may be placed within the shelf
itself, preferably one or more situated within the read range of
each individual antenna. These RFID tags provide for each antenna a
known response when that antenna is read during a self-test mode.
Thus, whether or not the shelf supported any RFID-tagged items,
there would always be at least one self-test RFID tag that should
be found in range of the antenna. If such RFID tags were not found,
the control unit 124 or secondary control unit 125 may institute a
self-tuning process. If after self tuning the self-test RFID tags
could still not be read, then a message could be sent to the
electronic network indicating the need for shelf maintenance.
Instead of placing the self-test RFID tags within the shelf, they
could also be placed elsewhere in range of the antennae, for
example on the rear or side wall of a shelf.
[0119] FIG. 11A is diagram illustrating alternate antenna loop
configurations within a single shelf unit. Shelf 300 contains a
single antenna loop 301. Shelf 310 contains antenna loops 311 and
312. With more than one loop within a shelf, there arise multiple
operating modes. For example, loop 311 could be active, or loop 312
could be active, or both loops could be active or inactive at the
same time. The present invention contemplates that both loops could
be active simultaneously with a phase difference in their input RF
signal. Such as phase difference can be introduced by various
electronic means well known to those skilled in the art. For
example, a phase difference can be introduced by using a different
length coaxial cable to feed one antenna loop as compared with the
other.
[0120] As seen in FIG. 11A, shelf 320 contains four antenna loops
321-324. This is shown as an example, since there may be more or
less than four antenna loops, and other configurations may be used
as would be recognized by those skilled in the art based on the
disclosure herein. The four loops 321-324 can be activated in
different combinations, for instance loops 321 and 322, 321 and
323, or 321 and 324 can be simultaneously activated. In particular,
if a pair of loops is active, with a phase difference between the
active loops, the RF field vector may be shifted in order to better
read antenna tags that are in different physical orientations.
Therefore, use of phased antenna loops may provide better
"coverage" for reading tags, when compared to non-phased loops.
[0121] FIG. 11B illustrates a top view of several shelves 400, 410,
420, 430, 440, and 450 supported upon a fixture 460. Each shelf
has, by way of example, four antennae. For example shelf 410
contains antennae 411-414. Furthermore within each shelf and
proximate to each of the antennae are one or more RFID tags. In
FIG. 11B there are four tags per antennae, the tags being
designated a-d. Tags within the shelf are useful for a variety of
functions. A smaller or greater number of tags may be used as would
be recognized by those skilled in the art.
[0122] For example, if antenna 411 is turned on at a relatively low
power, it should be able to read tag 411c, which is located, for
example, approximately in the center of antenna 411. Of course, one
of skill in the art would recognize that depending on the antenna
and tag design, at low power, tags at locations closer to the
antenna conductor may be used since they would be read more
readily. Thus tag 411c may be used to test whether antenna 411 is
functioning properly. If the power is increased antenna 411 should
also be able to read tags 411a, b, and d, which are located near
the periphery of antenna 411. By varying the power during a
diagnostic or self-check mode, the system should be able to
determine how much power is required for antenna 411 to function
effectively. Shelf tags may be arranged at several distances from
the center of each antenna in order to provide this
information.
[0123] As the power to antenna 411 is increased, it may eventually
be able to read shelf tag 412b associated with the adjacent antenna
412. The system may thus determine that antenna 411 and 412 are
adjacent. This information may then be used by the system to
determine which adjacent antenna may need to be detuned when a
given antenna is operating. The fact that antennae 411 and 412 are
adjacent could already have been established when shelf 410 was
fabricated. However, when several shelves are placed adjacently in
a retail store, it may not be possible or convenient to determine
in advance which shelves are to be adjacent. The shelf tags may be
used to establish which shelves or antennae are adjacent after the
system is assembled.
[0124] For example, antenna 411 operated at normal power may also
detect shelf tag 404d associated with adjacent antenna 404 on
adjacent shelf 400, whose adjacent position may not have been
established prior to shelf placement, and shelf tag 441a associated
with adjacent antenna 441 on the adjacent shelf 440 on the opposite
side of the gondola (or a common support structure for shelves),
whose adjacent position may not have been established prior to
shelf placement.
[0125] It is may be designed that antenna 411 operated at normal
power or slightly higher power may be able to read further into
adjacent antenna areas, for example reading shelf tags 404c, 412c,
and 441c. Thus the functionality described herein may be achieved
using only a single shelf tag in the center of each antenna.
[0126] Although shelf tags may be useful for the purposes described
above, they may slow the system response by increasing the number
of tags to be read. It may therefore be a desirable option to use
for the shelf tag unique ID serial numbers a specific range of
serial numbers that may be directed by the system to a "quiet"
mode, that is, not to respond during normal operation, but only to
respond during diagnostic or setup operations.
[0127] One or more antennae may be contained or hidden within each
shelf. The antenna loops may be made using conductive materials.
These conductive materials may include metallic conductors such as
metal wire or foil. The conductive material may also be strips of
mesh or screen. In one embodiment, the antenna loops may be made of
copper foil approximately 0.002'' thick and 0.5'' wide. These loops
may be contained within a thin laminate material such as a
decorative laminate that is applied to the surface of a supporting
shelf material. The loops may also be laminated within glass. The
loops may also be adhered to the exterior of a laminated material,
glass, or other supporting structure. If additional load bearing
support or stiffness is desired, such supporting shelf material may
be any material capable of supporting the shelf contents, or
providing structural rigidity, as would be recognized by those
skilled in the art. Examples of such materials include wood,
plastic, rigid plastic foam, glass, fiberglass, or paperboard that
is corrugated or otherwise designed to provide stability. An
RF-blocking material may be applied to or incorporated into the
bottom surface of the shelf, if desired, to prevent detecting RFID
tags that may be under instead of the target tags above the shelf.
It is to be understood that the intelligent station herein
described as a shelf could also be used in a vertical or other
angular orientation and the RF blocking material would then be
applied in an appropriate orientation to better isolate target tags
intended to be read from other adjacent tags.
[0128] An RF-blocking material applied to or incorporated into the
bottom surface of the shelf, or present in any underlying metal
support such as an existing metal shelf, will substantially prevent
RF energy from going "below" the shelf. Alternatively, an RF
blocking material may also be incorporated within the interior of a
shelf. This is an advantage if it is desired that the shelf sense
only tagged items on (above) the shelf. However, a consequence of
such an RF-blocking material (whether deliberately provided in the
shelf construction, or coincidentally present as a pre-existing
shelf structure) is that while nearly completely restricting the RF
energy below the shelf, the RF-blocking material under the shelf
also reduces the "read range" above the shelf. To compensate for
this otherwise reduced read range, a layer of compensating material
may be provided just below the antenna loops (that is near the top
of the shelf structure). Such a material would be non-conductive
and have a high magnetic permeability. Examples are Magnum
Magnetics RubberSteel.TM. or a flexible ferrite magnetic sheet
having a high in-plane magnetic permeability. Such an in-plane
magnetic permeability is achieved by using an isotropic ferrite
sheet, not a conventional anisotropic ferrite sheet whose
permeability by design is normal to the sheet. The presence of a
layer of this compensating material between the antenna and the
RF-blocking material, enables higher flux density between the
antenna and the RF-blocking material. Consequently the flux density
can be higher above the shelf, thus giving better sensing range
("read range") for a given shelf thickness.
[0129] The antenna loops, laminated within or attached externally
to thin supporting materials, may be disposed in a non-planar form,
for example, as curved panels that may be used in certain display
cases, beside some clothing racks, or for tunnel readers that may
be used at a checkout stand, etc.
[0130] The examples herein discuss loop antennas, which are
typically used for readers operating at RF frequencies such as
13.56 MHz. It is possible that items within the intelligent station
may contain tags operating at other widely different frequencies,
such as 915 MHz, 2.45 GHz, or 125 kHz. The intelligent station may
be configured to read these or other frequencies, by providing
suitable antennae, for example multiple loop antennae for 125 kHz,
and dipole antennae for 915 MHz or 2.45 GHz. Antennae within the
intelligent station may be provided for one or several of these
frequencies. Each antenna would preferably have its own separate
switch and tuning circuit. All intelligent stations would share a
single common RF cable, and a single common control cable.
Intelligent stations may be constructed so that all areas on each
intelligent station may read all desired frequencies (that is each
area is served by multiple antennae), or different areas on a given
intelligent station may be provided with specific antennae for a
specific frequency. Intelligent stations operating at different
frequencies could all be interconnected. An intelligent station
operating at more than one frequency would require a so-call "agile
reader" unit that can be configured operate at more than one
frequency.
[0131] In the preferred embodiments, the antenna loops discussed in
present application may be placed, for example, upon shelves so
they would be placed underneath products by being incorporated into
mats that are placed on shelves. The loops are thus encapsulated in
an appropriate rigid or flexible substrate well known to those
skilled in the art. Examples of suitable substrate material include
a laminated structural material, silicone rubber, urethane rubber,
fiberglass, plastic, or other similar material that protect the
antenna loops and provide some physical offset to prevent
electromagnetic interference in case the antennae are placed on
metal shelves, walls, or surfaces.
[0132] The encapsulation material or the shelves may be provided
with holes or grommets for hanging on vertical surfaces such as the
backs of shelves. In an alternate embodiment, the encapsulation
material also may be provided with a pressure sensitive adhesive to
help attach to a desired surface. The "front" or "shelf" edge of
the encapsulation may also be provided with low power light
emitting or other display devices that may be turned on by the
reader unit or a sequencer unit such as a secondary controller unit
within the shelf so that activity of particular display devices may
be visually coordinated with the activities of correspondingly
positioned reader antennae. Alternatively or in addition, the
display devices may also be used to display additional information
such as pricing or discounts.
[0133] Besides the ability to read RFID tags, the intelligent
station may have additional "peripheral" devices that may
communicate information through the digital data cable. For
example, the intelligent station system would provide a digital
data communication highway for add-on or peripheral attachment
devices including but not limited to computer terminals, display
devices, modems, bar code readers, temperature sensors, locking
devices for enclosed or tethered merchandise, etc. The digital data
communication highway may be incorporated into the wiring system
that sends digital control and data information between controller
124 and secondary controllers 125, or it may be one or more
separate digital data communication highways that are made up of
wiring that runs through and connects between the stations, with
the stations provided with ports through which to connect the
add-on or peripheral devices. The digital data communication
highway facilitates the transmission of data in both directions
between the intelligent stations system (including the controller
124 and secondary controller 125) and the electronic network.
Electrical power may also be provided for the add-on or peripheral
devices through wires that run through the stations.
[0134] It should be understood that, whether or not add-on or
peripheral devices are used, electrical power other than RF power
may be used by the stations, for example direct current (DC) used
by the secondary controller 125, and by the switches and tuning
electronics. Such electrical power may be provided by one or more
dedicated wires, or it may be incorporated into the digital
communication highway or with an RF cable.
[0135] As an example, an RF cable may comprise two conductors, for
example in a coaxial cable, the center conductor and the sheath
conductor. The RF cable carries an RF signal. A DC voltage may be
superimposed on the RF signal, in the same RF cable, to provide DC
power to intelligent stations. If the DC voltage, for instance 18
volts DC, is higher than needed for some devices in the intelligent
station (for instance 5 volts DC), a voltage regulator may be used
to decrease the voltage to within usable limits.
[0136] As a further example, digital communications may be carried
on the same RF cable. For instance, the DC voltage superimposed on
the RF cable may be switched between two DC levels (for example 18
volts DC and 12 volts DC) to accomplish non-RF digital
communications on the RF cable Therefore, a primary controller may
send information to secondary controllers by using such digital
communications.
[0137] As a further example, a secondary controller may send
information to a primary controller in digital form over an RF
cable by switching on and off an electrical load to thereby drain
current from the RF cable. This in turn may be sensed at the
primary controller. The use of voltage level and the use of load
level may be done simultaneously to achieve two-way digital non-RF
communication through the RF cable.
[0138] As another example, in the shelf embodiment, another device
that may advantageously be incorporated into the shelf is a plug-in
bar code reader that could interface to the secondary control unit
125. When the shelf was being stocked, the bar code reader could be
used to scan the packages being placed on the shelf. The bar code
data would then be sent back to the electronic network along with
the unique RFID tag serial number. If the product identity defined
by the bar code was not previously associated with the unique RFID
tag serial number, the association would now be completed within
the data store. Otherwise the bar code scan could serve as a
verification of the data store information. The use of the bar code
device would further enable the shelf to provide benefits even
during staged introduction of RFID tagged merchandise. By comparing
the number of items stocked onto the shelf (as identified by the
bar code scanner in conjunction with a simple numeric keypad),
against the number of same items sold (as determined by existing
scanners at the checkout line) it could be determined approximately
how much merchandise remained on the shelf, and whether restocking
was necessary. Likewise barcode scanning at the shelf itself could
be utilized to provide current pricing information retrieved from
the electronic network and displayed through alphanumeric displays
at the shelf.
[0139] In another embodiment, the shelf or intelligent station may
be provided with environmental sensors, to monitor or measure, for
example, temperature, humidity, light, or other environmental
parameters or factors. Since the system is able to determine what
items are on the shelf, the system could keep track of the
environment for each item and provide a warning if environmental
conditions were out of limits for specific types of items. Separate
limits could be defined for each group of items.
[0140] One or more proximity sensors, for example, infrared sensors
or capacitive sensors, may be located on the shelf to detect the
presence of a shopper and determine whether to increase the reading
frequency at that shelf in order to give the shopper rapid feedback
when an item is moved from the shelf. The means of detecting a
shopper would be located at the front edge of the shelf, where they
would not be obstructed by merchandise. Infrared or capacitive
sensors could sense the presence of a shopper by detecting body
heat from the shopper, or a change in local capacitance due to the
shopper being in front of the shelf, or the shopper's hand or arm,
or merchandise, moving near the front of the shelf. Other means of
detecting the presence of a shopper could include visible or
infrared light sensors along the front edge of the shelf to detect
the shadow of a hand or arm reaching for merchandise on the shelf.
The light source in this case could be ambient visible light, or
visible or IR light from sources located below the next higher
shelf, or from sources overhead or on the ceiling of the store.
Store security cameras could also be used to detect the presence of
shoppers and to direct the intelligent station to increase reading
frequency. Likewise, audible/visual signals or displays or can be
activated when a shopper is sensed and for some time thereafter
rather than being activated at all times in order to conserve power
and component life. Likewise information regarding the proximity of
a shopper to the shelf could be relayed back to the electronic
network to help analyze shopper traffic patterns, or length of time
spent at a particular shelf. The shopper location data could also
be fed to store security systems for use in conjunction with
scanning patterns of store surveillance cameras.
[0141] Likewise the shelf data relayed back to the electronic
network can be used to determine if an unusually large number of
items are suddenly removed from the shelf. If this occurs, a
security camera can be directed at the shelf to take a picture of
the shopper who removed the items. If the items are not paid for
when the shopper leaves the store, appropriate action can be taken
to stop the theft.
[0142] Another device that may be incorporated into the shelf is a
Hall effect or other similar proximity type sensor to detect
movement of tags or presence of a shopper. This information may be
used similarly to that described in the preceding description
regarding an infrared sensor.
[0143] Another use of the shelf would be to detect the presence of
"customer tags" associated with shoppers, that could be used to
help shoppers find predetermined merchandise items, such as the
correct size of clothing items, whereby visual or audible
indicators on the shelf could be activated to direct the shopper
toward the desired items. Also the "customer tag" when placed on a
shelf where a desired item was out of stock, could be used to give
the customer a "rain check" and or discount on the item when it
came back into stock, or information about the item being in the
stock room, at another store, or on order. This could be useful to
track when a shopper did not purchase an item because it was out of
stock.
[0144] Another use of the shelf would be to provide "feedforward"
information to predict when more cashiers would be required at the
checkout lanes, or when more stockers were required. This could,
for example, be done by monitoring the amount of merchandise being
removed from shelves, and thereby deducing the volume of
merchandise that would be arriving at the checkout lanes. The
storekeeper or store manager thereby could schedule the checkout or
restocking personnel to optimize how their time is spent, help
schedule break time, etc.
[0145] Another use of the shelf could be to detect the presence of
a "stocking tag" or "employee tag," or a pushbutton or keyed input
sequence, to alert the system that the shelf is stocked completely
and the database is made aware that the current stock level is the
full or target level. This method could be used when item stocking
patterns were changed, to update the target level.
[0146] The shelf system could be used to suggest, for all shelves
covered by the system, based on the price, traffic, and shelf
space, the most optimal stocking pattern, which may involve
changing the target inventory for all items. Calculating such a
stocking pattern would require knowledge of how many of each SKU
item would fit on a given shelf area, and how much shelf area was
covered by each shelf antenna.
[0147] In one aspect of the present invention, it would be
advantageous for the shelf system to know the physical location of
each shelf, which may not necessarily be obvious even from unique
Ethernet or RS-485 addresses or other networking addresses.
Therefore, the present invention contemplates incorporating a GPS
transducer into each shelf. A more practical solution may be to,
instead, provide a portable GPS unit that could be plugged into a
USB port (or other similar compatible port) on each shelf, when the
shelf was assembled, to identify its location. For example, a GPS
unit could be combined with the servomechanical tuning unit used to
set up the shelf after its installation.
[0148] Alternately, a GPS unit with a programmable RFID tag could
be placed upon a shelf and communicate back to the main controller,
through the RFID system, what the coordinates of the shelf are. One
way of accomplishing this would to use a GPS system connected to a
specialized RFID tag having additional storage blocks for
information besides its unique serial number. Such a tag would use
an integrated circuit with connections to its tag antenna also to
communication circuitry to receive data from an outside source,
such as the GPS system. The GPS system could be configured to write
the spatial coordinates in the additional storage blocks. A known
serial number or numbers could be used in the specialized RFID tag,
and the RFID system, upon detecting such a specialized RFID tag
could interrogate the tag to determine the stored spatial
coordinates and associate then with the shelf and antenna that was
being read.
[0149] The antenna shape need not be confined to single-loop
antennae. A single loop antenna is a form factor that may typically
be used with high RFID frequencies such as 13.56 MHz. A multi-loop
antenna 1215 may be used at a lower frequency such as 125 kHz, or
to permit lower current operation at high frequencies such as 13.56
MHz. The use of lower current antennae may permit using lower power
switching components. Forming multi-loop antenna may require
antenna components such as the wire in the loops to be in close
proximity to one another, and therefore the wire may preferably be
insulated.
[0150] Tuning components associated with the RFID antennae, for
example, rotary trim capacitors or capacitor banks, may require
access during use. Suitable access may be provided, for example in
a shelf embodiment, by providing removable cover devices, or holes
in the shelf
[0151] For attaching conductive antenna materials onto supporting
laminate or other structures, a variety of methods may be utilized.
For example, a metal foil may be laid down onto a substrate in web
form (such as a web of paperboard) or planar form (such as a sheet
of paperboard, sheet of laminate, wood or plastic board, etc.) by
an automated machine using two or three dimension positioning
mechanisms to feed the foil from a reel onto the substrate in the
desired antenna pattern.
[0152] If the supporting material is wood, a milling machine may be
used to form grooves into which conductive wire may be secured in
order to form antenna loops. The same method may be used if the
supporting material is plastic, or, a heated pattern may be pressed
into the plastic to form grooves in which conductive wire may be
secured. A plastic substrate may be molded with grooves to hold
wire conductors, or the plastic substrate may be molded with a
repeating rectilinear pattern of perpendicular grooves that permit
forming antenna loops in a large number of patterns. In any of
these methods, holes may be drilled, punched, or molded for
securing the ends of the antenna wires. These holes may extend
through the substrate to become accessible for connection or
insertion into tuning circuits used to tune the antenna loops.
[0153] Another method of forming antenna loops is to wrap the
conductive wire around a series of pins similar to a loom, then
invert the loom and press the conductors onto a substrate. The
substrate may be precoated with adhesive to hold the conductors
when the loom is removed. Alternately the substrate may be soft
enough to allow the conductors to be pressed into the surface of
the substrate. Alternately the substrate may be a thermoplastic and
the conductors may be preheated so that they partly melt the
substrate on contact and become embedded in it's the surface of the
substrate. The pins used on the loom to form the antenna loops may
optionally be spring-loaded so that when the loom is pressing the
conductors onto the substrate, the pins may optionally retract into
the loom.
[0154] In more detail, FIG. 12 shows one method of making a wire
antenna. FIG. 12 is not intended to limit the present invention
since one skilled in the art would recognize various modifications,
alternatives, and variations. A substrate 1100 is provided, such as
a wood, plastic, rubber, high density foam, or similar material.
Grooves 1110 are provided in the substrate, typically in a grid
pattern. These grooves may be made by machining, molding such as by
hot or cold-pressing or injecting molding, casting, hot branding
(for example with wood), etc. Pressing methods may use platen
(stamping) or rotary devices. Preferably holes 1130 are provided at
intersection points in the grooves, by the same methods or by
drilling or punching. A large part of the area on substrate 1100 is
still occupied by the areas 1120 between grooves. Thus the
substrate 1100 still has an essentially planar upper surface, so
that loads may be borne by the surface and a covering, film,
laminate, or veneer may be applied to provide a planar finished
surface. The areas 1120 are also known to be unoccupied by antenna
wires, and these areas may be provided by casting, drilling,
punching, etc. with holes to accommodate screws or bolts to attach
to other structures. The holes may also be used for attachments
such as pegboard or display hooks, or through holes for wiring,
ventilation, sound from loudspeakers, placement of small lights,
etc.
[0155] Antenna loop 1200 is shown that has been formed by placing
or pressing wire of a suitable diameter into some of the grooves
1110. The ends 1201 of the antenna loop are held in place by
securing them into holes 1130. The holes can be entirely through
substrate 1100, so that they may be connected to circuitry on the
other side of the substrate. Likewise antenna loop 1210 is shown
being formed, with wire end 1211 already secured in one hole and
wire end 1212 shown ready to be secured into another hole.
[0156] Besides simply pressing bare wire through the holes to
secure the ends, the wire may be precut to the needed length, and
the ends fitted with grommets 1140, buttons, or other mechanical
devices that fit into holes 1130. These grommets may be soldered
onto the wire for better conductivity. As an alternative to
inserting them into holes 1130, the grommets may be slightly larger
diameter than the width of the grooves 1110, so that the grommets
will only fit at points where two grooves intersect, as shown in
FIG. 12A. Alternately during forming of the groove pattern, the
intersection points may be made larger than the groove widths as
shown in FIG. 12B, to hold a larger grommet 1141. The grommets may
be bar shaped (1142) or tee shaped (1143) to fit in the
intersection points as shown in FIG. 12C. They may also be
cross-shaped. They may be fitted with pins to protrude down into or
through substrate 1100, or to extend upward out of substrate 1100.
The pins may fit into sockets on, or holes in, the circuit boards.
The grommets (e.g. 1140 or 1141) may be hollow to accept other
wiring or pins. They may incorporate externally threaded pins or
internally threaded holes. The grommets likewise may incorporate
internal or external barbs or spring-loaded parts to hold them in
place or to assist in connecting to external circuitry. The antenna
wires attached to the grommets may also be secured by barbs.
[0157] The substrate 1100 may be provided with recesses (not shown)
in which to position circuitry (not shown), and such circuitry
installed before or after the wires, and the wires attached to the
circuitry by soldering or use of grommets, barbs, etc.
[0158] Instead of the grooves 1110 forming a regular grid or
criss-cross pattern, which allows for multiple antenna patterns to
be created, the grooves can instead be provided in "custom" form to
comprise only the grooves desired for the actual antennae to be
produced. FIG. 13 shows such an embodiment. The grooves, for
example 1220 and 1230, can be formed by the same methods described
above, as can the holes 1221 and 1231.
[0159] Since the grooves and holes hold the wire securely, the wire
may be easily inserted by hand into the substrate, or the process
may be mechanized. After all desired antennae have been formed in
the substrate, any open grooves may be filled with plastic or any
other suitable material. A covering laminate, film, or other layer
may then be applied on top of the substrate. This covering may be
an injection-molded layer of material, or melt-cast layer, or
liquid cast layer that cures by chemical reaction or heat (such as
an epoxy material or silicone compound), or evaporation (such as a
latex material).
[0160] The combined substrate and covering then comprise an antenna
mat. Depending on the materials, the antenna mat may be flexible or
rigid. The antenna mat may also be attached to a planar or
non-planar supporting material such as a wood, plastic, fiberglass,
etc. board.
[0161] The antenna shape need not be confined to single-loop
antennae. FIG. 13A shows single loop antennae 1200 and 1210, a form
factor that might typically be used with mid range RFID frequencies
such as 13.56 MHz. Also shown is a multi-loop antenna 1215 that
might typically be used with a lower frequency such as 125 kHz.
Forming multi-loop antenna 1215 may require the wire loops to be in
close proximity to one another, and therefore the wire may
preferably be insulated. It may be desired to have a wire crossover
1216 as shown, or no crossover as denoted by dotted line 1217. The
distance between grooves may have to be narrower for multi-loop
antennae. Also shown is the shape of a dipole antenna 1218 that
might typically be used with higher frequencies such as 915 MHz or
2.45 GHz. The ends 1219 shown for the dipole antenna are bent to
denote a method for holding these otherwise loose ends by inserting
the ends into holes in the substrate during fabrication.
[0162] In the embodiment of FIGS. 12 and 13, the grooves are
created before the antenna wires are set in place. A different
embodiment is shown in FIG. 14. An upper plate 1300 is provided
which has a pattern of holes 1301 for holding pins 1302. The pins
may be threaded and the holes tapped so that the pins may be
secured by screwing them into the holes. Thus the number and
placement of the pins may be varied.
[0163] A lower plate 1310 is provided with matching holes 1311.
When the plates 1300 and 1310 are brought together as shown at
arrow "A", pins 1302 protrude through holes 1311. Pins 1302 may
then be used to define the corners of wire antennae that are wound
around the pins under the lower plate 1310. For example antenna
1240 is formed using pins to hold the wire at three corners. At the
fourth corner, the two wire ends 1241 are inserted up through open
holes 1311 in the lower plate 1310. Another example antenna 1250 is
formed using pins at all four corners. Grommets 1251 attached to
the ends of the wire loop are held over two additional pins.
Instead of securing the wire ends within the plate area, they may
also extend beyond the plate as shown by the dotted lines at 1252.
In this case the wire ends would be secured by other means (not
shown).
[0164] The combined assembly 1330 of upper plate 1300 and lower
plate 1310 with attached pins, wires, grommets, etc. is then
inverted over substrate 1320 as shown by arrow "B". The antennae
1240 and 1250 are transferred onto the substrate 1320 by one or
more of the following or similar methods.
[0165] a) An adhesive coating or film is applied to the substrate
1320. The combined assembly 1330 is lowered onto the substrate
1320, and lower plate 1310 is pressed against the substrate. The
antennae 1240 and 1250 adhere to the adhesive. If upper plate 1300
is lifted slightly during the pressing step, the pins 1302 will not
penetrate the substrate 1320. If upper plate 1300 is also kept
under downward pressure, the pins 1302 will make holes in the
substrate 1320. Any grommets 1251 will be pressed into the
substrate. After the adhesive set, the combined assembly 1330 is
lifted, leaving the antenna pattern attached to substrate 1320.
[0166] b) Method (a) may be used, with sufficient pressure to force
the antenna wires partly or completely below the surface of the
substrate 1320. This method could be used, for example, with a high
density foam substrate 1320 which requires minimal force to press
the wires below the surface.
[0167] c) Method (b) may be used, with the wires 1240 and 1250 and
grommets 1251 heated to a temperature above the softening point of
substrate 1320, so that on contact and pressure, the substrate is
softened or melted slightly to accept the wires and grommets. One
method of heating the wires is to pass an electric current through
them before or during pressing against the substrate. The upper
plate 1300 may be released during the pressing step so that the
pins 1302 retract and do not penetrate into substrate 1320.
[0168] d) The substrate instead of being a solid material 1320 may
at this point be cast onto the wires by liquid casting of chemical,
thermal, evaporative or otherwise setting material, or by injection
molding, of a material to the lower surface of lower plate
1310.
[0169] Lower plate 1310 and pins 1302 may be precoated with a
release agent to prevent sticking. Such a release agent would be
applied before the wires are attached, so that release agent is not
applied to the wires. Also, lower plate 1310 may be a non-stick
material, for example Teflon or coated with Teflon or a similar
non-stick material. If an injection molding is used, lower plate
1310 may be cooled by internal passageways to speed up cooling of
the injection-molded material.
[0170] After these steps, the antennae 1240 and 1250 may be
attached to circuitry using wire ends 1241 or 1252, or grommets
1251.
[0171] In all embodiments, it is understood that the wires may be
bare (except at crossovers) or insulated. The cross section of the
wires may be a solid cylinder as is typically the case with wire,
but it may also be square, rectangular, oval, U shaped or channel
shaped, vee-shaped, etc. The main requirement of the wire is that
regardless of shape it must be conductive and must have a shape and
cross-sectional stiffness that promotes its being held in the
grooves. The wire may be single conductor (typically known as
"solid" conductor), or multistrand. It may be twisted or woven. It
may be coaxial cable, in which case the external braid would be
used as the active conductor for the RF signal.
[0172] FIG. 15 is a diagram that illustrates a device and method of
applying foil tape ribbons to a web or planar substrate to form
foil antennas according to the present invention. Such foil
antennae have several uses, for example, they may be used as
transceivers or readers for communicating with RFID tags in RFID
systems that may be used for inventory control. FIG. 15 is not
intended to limit the present invention since one skilled in the
art would recognize various modifications, alternatives, and
variations. A substrate 2100 is provided. This may be in web form,
as shown, in which case traction rollers 2110 or other means may be
provided to move the web. In the example shown in FIG. 15, such
movement would be discontinuous. The web 2100 would be indexed
forward a distance, then stopped while one or more conductive
pathways were deposited onto substrate 2100. Once the conductive
pathways had been deposited on substrate 2100, the web would be
indexed forward again and the cycle repeated.
[0173] A support plate 2120 is provided under the substrate. This
support plate 2120 may incorporate a vacuum hold-down system (not
shown) to temporarily fix the substrate 2100 to the support plate
2120. The support plate 2120 itself may also be movable in the X
and Y directions to assist in the process of depositing conductive
pathways.
[0174] An applicator means 2200 is provided for depositing the
conductive pathways 2300. This applicator 2200 will be described in
more detail later. An x-y stage 2400 is provided for moving
applicator 2200. The x-y stage may include a frame 2401, a
positioning means 2402 that moves in the principal substrate axis
("x" or "machine" direction), and a second positioning means 2403
that moves in a perpendicular axis ("y" or "cross" direction.) A
rotational positioning means 2404 may be provided to turn the
applicator 2200 in any angle relative to substrate 2100, to
facilitate the operation of applicator 2200. It is anticipated that
the substrate 2100 movement and the applicator 2200 movement will
be automated by computer means that control motors driving traction
rollers 2110, and positioning means 2402, 2403, and 2404, in
addition to more controls within applicator 2200.
[0175] In FIG. 15 the x and y positioning means 2402 and 2403 are
shown as rack and pinion gearing, but could include other means
such as cables, linear motors, stepping motors, or other means that
can achieve fairly repeatable positioning.
[0176] FIG. 16 shows another method of depositing conductive
pathways on a substrate to a form foil antenna. Support member 2500
extends across the substrate and holds two or more stationary
positioning means 2501 that in turn support applicators 2200. The
stationary positioning means 2501 can be moved by hand across the
support member 2500, then fixed in place for example with a
thumbscrew. Enough stationary positioning means 2501 with
applicators 2200 are provided to lay down along the machine
direction (x) as many lengthwise conductive pathways 2301, 2302 as
needed. In the example shown, lengthwise conductive pathway 2302 is
provided with a skipped area 2303 that will be used for connection
to external circuitry.
[0177] Support member 2510 extends across the substrate and holds a
traversing means 2511 that in turns supports another applicator
2200. Traversing means 2511 can move on demand across the substrate
in the cross direction (y) to deposit crossways conductive pathways
2304 and 2305 that connect the lengthwise conductive pathways 2301,
2302.
[0178] Operation according to FIG. 16 is therefore as follows: The
substrate 2100 is moved forward by traction rollers 2110 (or by
movement of support plate 2120). Meanwhile the applicators 2200
attached to stationary positioning means 2501 deposit on demand
lengthwise conductive pathways 2301, 2302 that may contain skipped
areas 2303.
[0179] At the appropriate times, the substrate 2100 movement is
paused so that the applicator 2200 attached to traversing means
2511 can deposit crosswise conductive pathways 2304, 2305. The
pause in the X direction movement of substrate 2100 may occur in
the middle of the process of depositing one or more of the
lengthwise conductive pathways 2301, 2302. Alternately, for
depositing the crosswise conductive pathways 2304, 2305, applicator
2200 may be fixed in position and the Y direction movement provided
by movement of support plate 2120.
[0180] The decision of whether to move substrate 2100 in web form
or in sheet form will depend on several factors. The substrate may
be available in roll form advantageous to web handling, or in cut
form advantageous to sheet handling. Some substrates may not be
flexible enough for handling in web form, for example thick sheet
substrates or substrates that have been partly or completely
laminated and are no longer flexible.
[0181] The decision of which applicator system to use will also be
made based on several factors. The single head applicator design of
FIG. 15 minimizes the number of applicators, but slightly
complicates the applicator positioning. It may be slightly slower
than a multiple applicator design. However, it is quite flexible in
terms of making customized products, since every conductive pathway
may be customized. The multiple applicator system of FIG. 16
simplifies the positioning of the applicators, and may improve
speed for long production runs of single designs.
[0182] Instead of moving the applicators as in FIGS. 15 and 16, the
substrate itself could be moved in the x-y plane to help create the
conductive pathways. This would typically require more floor space
than when moving the applicators, and it would be complex if the
substrate was in roll form.
[0183] FIG. 17 shows a cross section of an applicator 2200 for
depositing conductive pathways. FIG. 17 is not intended to limit
the invention since one skilled in the art would recognize various
modifications, alternatives, and variations. As shown in the
embodiment of FIG. 17, the applicator 2200 would move to the right
relative to substrate 2100. A supply roll 2210 provides a
continuous conductive strip 2211 through a pair of feed rolls 2212
that are computer controlled to provide the continuous strip 2211
only when demanded. The strip 2211 goes into a chute 2213 and past
a cutter 2214 that is computer controlled and may be turned at any
angle to provide angled cuts if desired. The strip 2211 continues
forward and out of the applicator 2200, at which point an optional
release liner 2215 can be removed and wound around roller 2216 to
be taken up onto tension winding roll 2217.
[0184] A second, optional supply roll 2220 provides a continuous
insulating strip 2221 through a pair of feed rolls 2222 that are
computer controlled to provide the insulating strip 2221 only when
demanded. The strip 2221 goes into a chute 2223 and past a cutter
2224 that is computer controlled. The strip 2221 continues forward
and out of the applicator 2200, at which point an optional release
liner 2225 can be removed and wound around roller 2226 to be taken
up onto tension winding roll 2227.
[0185] A pressure device 2230 is provided to push the strips 2211
and/or 2221 onto the substrate 2100. The pressure device may be a
wheel or roll as shown, or a sliding member, or a reciprocating
clamping means. The pressure device 2230 may be heated to help set
an adhesive integral to strips 2211 or 2221, or provided externally
as described later. The pressure device 2230 may be patterned or
knurled, for example to help press the strips 2211 or 2221 onto the
substrate 2100, or even to slightly crimp the strips 2211 or 2221
into the material of the substrate 2100. This might remove the need
for adhesive, at least in sheet-fed operations. It is also
envisioned that strip 2211 may be perforated with holes to improve
the adhesion of resin between layers of substrate in the final
laminate, even in the areas where the strip 2211 exists.
[0186] A hole punch 2240 is provided to perforate the substrate
2100 on demand to create openings through which electrical
connections may be made to the conductive strip 2211. Preferably
the hole punch 2240 is provided with an internal vacuum connection
to remove the waste substrate material created during a hole
punching operation.
[0187] An adhesive dispenser 2250 is provided to dispense glue 2252
through needle 2251, in order to hold strip 2211 or 2221 to the
substrate. Preferably the adhesive is a rapid set material such as
a hot melt glue, heat set glue, or epoxy. This adhesive is
deposited on demand under computer control to be present under the
strip 2211 or 2221, but not deposited if no strip is deposited in a
given area. Any adhesive that may be used should not degas when
pressed at high temperature, otherwise the integrity of the
laminate may be compromised.
[0188] The conductive strip 2211 or insulating strip 2221 may also
be provided with their own adhesive layers to attach it to the
substrate 2100.
[0189] The adhesive used to attach the strips 2211 and 2221 to
substrate 2100 would typically be non-conductive, since conductive
adhesives are more expensive. However, it will be necessary in some
places to electrically join parts of the conductive pathway 2300,
and for this a conductive adhesive or material would be required.
For simplicity it might be decided to use conductive strip 2211
with an integral conductive adhesive, but this would be expensive.
Another solution is to provide within the applicator 2200 a
reservoir 2260 of conductive adhesive to be applied through needle
2261 in droplet form 2262. A drop 2262 of the conductive adhesive
could be applied on top of a previous segment of conductive trace
2300, just before starting the next segment on top of the previous
segment. The action of pressing means 2230, with heat and pressure,
would then electrically join the two segments. The conductive
adhesive drop 2262 could be a drop of metal solder in either a low
melting form, or in suspension (either form would be remelted by
the pressure means 2230).
[0190] FIG. 18 illustrates a method using the apparatus shown in
FIG. 15 to lay down a simple rectangular conductive pathway. The
steps are as follows
[0191] Substrate 2100 is indexed forward in the x direction by
rollers 2110.
[0192] Using X positioning means 2402 and y positioning means 2403,
the applicator 2200 is moved to point "a" and "h" where the hole
punch 2240 makes two holes in the substrate 2100.
[0193] Using X positioning means 2402, the applicator 2200 is
positioned to point "b".
[0194] The applicator 2200 moved by X positioning means 2402, uses
internal devices 2210-2217 to lay down a conductive pathway 2300
from points "b" to "c." During this operation, cutter 2214 cuts the
strip 2211 at a precisely determined moment so that the conductive
pathway 2300 ends at point "c." Note that the beginning of the
conductive strip 2300, at point "b," slightly overlaps the hole
punched at "a."
[0195] X positioning means 2402 is used to move the conductive
adhesive applicator 2261 to point "c", where a drop of conductive
adhesive 2262 is placed on the end of the conductive pathway
2300.
[0196] Rotational positioning means 2404 rotates the applicator
2200 by 90 degrees so that it can run in the cross direction Y.
[0197] X and Y positioning means 2402 and 2403 are used to place
the applicator 2200 to point "c."
[0198] The applicator 2200 moved by Y positioning means 2403, uses
internal devices 2210-2217 to lay down a conductive pathway 2300
from points "c" to "d." During this operation, cutter 2214 cuts the
strip 2211 at a precisely determined moment so that the conductive
pathway 2300 ends at point "d."
[0199] Y positioning means 2403 is used to move the conductive
adhesive applicator 2261 to point "d", where a drop of conductive
adhesive 2262 is placed on the new end of the conductive pathway
2300.
[0200] Rotational positioning means 2404 rotates the applicator
2200 by 90 degrees so that it can run in the machine direction
X.
[0201] X and Y positioning means 2402 and 2403 are used to place
the applicator 2200 to point "d."
[0202] The applicator 2200 moved by x positioning means 2402, uses
internal devices 2210-2217 to lay down a conductive pathway 2300
from points "d" to "e." During this operation, cutter 2214 cuts the
strip 2211 at a precisely determined moment so that the conductive
pathway 2300 ends at point "e."
[0203] X positioning means 2403 is used to move the conductive
adhesive applicator 2261 to point "e", where a drop of conductive
adhesive 2262 is placed on the new end of the conductive pathway
2300.
[0204] Rotational positioning means 2404 rotates the applicator
2200 by 90 degrees so that it can run in the cross direction Y.
[0205] X and Y positioning means 2402 and 2403 are used to place
the applicator 2200 to point "e"
[0206] The applicator 2200 moved by y positioning means 2403, uses
internal devices 2210-2217 to lay down a conductive pathway 2300
from points "e"to "f". During this operation, cutter 2214 cuts the
strip 2211 at a precisely determined moment so that the conductive
pathway 2300 ends at point "f."
[0207] Y positioning means 2403 is used to move the conductive
adhesive applicator 2261 to point "f", where a drop of conductive
adhesive 2262 is placed on the new end of the conductive pathway
2300.
[0208] Rotational positioning means 2404 rotates the applicator
2200 by 90 degrees so that it can run in the machine direction
X.
[0209] X and Y positioning means 2402 and 2403 are used to place
the applicator 2200 to point "f."
[0210] The applicator 2200 moved by x positioning means 2402, uses
internal devices 2210-2217 to lay down a conductive pathway 2300
from points "f" to "g." This last portion of the pathway 2300 is
not yet completed in FIG. 18. During this operation, cutter 2214
cuts the strip 2211 at a precisely determined moment so that the
conductive pathway 2300 will end at point "g." Note that the end of
the conductive pathway 2300, at point "g", will slightly overlap
the second hole punched at point "h."
[0211] Steps 2-20 are repeated for each conductive trace 2300 to be
applied to substrate 2100 on the exposed area of the substrate.
Then the substrate is indexed forward again starting with step
1.
[0212] Instead of forming the conductive trace 2300 by connecting
separate pieces of the foil strip 2211, the conductive trace 2300
may be formed from a continuous strip 2211. Instead of using cutter
2214 to cut the foil 2211 between segments at each corner, the
strip 2211 may be automatically folded over. For example, this may
be done by turning rotary positioning means 2404 through a 90
degree turn and pressing down on the folded corner so that the
trace 2300 lays flat at the corner.
[0213] FIG. 18A shows the result. The folded corner will have a
maximum of three overlapping thicknesses of foil. FIG. 18B shows
the result if the foil is at the same time twisted 180 degrees to
invert the tape. (This would require another positioning means, not
shown. Inverting the tape may be undesirable if the tape has an
adhesive coating, since the adhesive will now be facing away from
the substrate). The folded corner will have a maximum of two
overlapping thicknesses of foil.
[0214] FIG. 19 shows an embodiment where a conductive trace 2300
being laid down overlaps a previous conductive trace.
[0215] Before the overlapping segments of the second conductive
trace 2300 are laid down, strips "I" and "J" of non-conductive film
are laid down over the first trace, using applicator 2200. These
insulating strips "I" and "J" prevent electrical contact between
the separate conductive loops that are formed by the conductive
trace 2300. In similar manner, "cross-over" circuitry can be laid
down.
[0216] It is anticipated that the substrate 2100 with conductive
traces 2300, whether in sheet or web form, may be incorporated into
a laminated structure that may be used in a shelf, panel,
enclosure, spaces, or other form. An example of such a laminated
structure is shown in FIG. 20. The substrate 2100, which may be a
paper or paperboard material, is joined with additional plies 2600
and 2601 of similar or dissimilar materials, for example saturating
Kraft paperboard soaked in resin, and formed under heat and
pressure into a laminate 2610. Usually the outer ply or plies 2601
on the first surface opposite from the substrate 2100 would be a
decorative material that would for the "outside" of the resulting
product. Depending on the orientation of the outer substrate layer
2100, this laminate 2610 contains on its second surface, or just
inside that surface, the conductive traces 2300 already described.
The laminate 2610 may then be glued onto a heavier supporting
member 2620, such as a board made of wood, plastic, particle board,
corrugated cardboard, Westvaco Core-board, or similar. The surface
of laminate 2610 that is proximal to the conductive traces 2300 is
preferably glued to the supporting member 2620. Thus the full
thickness of the laminate 2610 protects the conductive traces 2300
from abrasion during use of the resulting combined structure 2630,
formed of laminate 2610 and supporting member 2620.
[0217] A conductive or metallic backplane 2625 may optionally be
applied to the bottom of the shelf to block RF energy from going
below the shelf, thus making the shelf operate with approximately
the same RF behavior regardless whether or not it was supported by
metal brackets or placed upon an existing metal shelf.
[0218] FIG. 21 shows how, before the supporting member 2620 is
glued to the laminate 2610, it is preferable to place inside the
supporting member 2620 one or more electronic circuits that
communicate with the conductive traces 2300, either by the latter
being directly exposed, or through the perforations already
described. To accommodate electronic circuits recesses may be
milled into the surface of the supporting member 2620. A
numerically controlled milling machine head 2700 could be used in a
positioning system similar in design to the system shown in FIG. 15
for laying down the conductive traces 2300, and could be run by a
same or similar computer control system that would control the
location and depth of recesses. For example, at the edge of the
supporting member 2620 is shown recess 2631 for accommodating an
external connector 2632. Within supporting member 2620 is shown
recess 2633 for containing electronic circuitry 2634 such as
switching and tuning circuitry. Spanning supporting member 2620 is
shown recess 2635 for containing wires or cables to connect the
circuitry components. The electronic circuitry 2634 may incorporate
spring loaded coils 2637 or fingers 2638 to make contact with the
conductive traces 2300 on substrate 2100 that is part of laminate
2610 to be attached to support member 2620. Said electrical contact
could be by pressure, by conductive adhesive or paste, or by solder
melted during the lamination process. The milling head 2700 may be
used to make grooves 2639 for access of tuning tools such as small
screwdrivers for adjusting trim capacitors within circuitry
2634.
[0219] Tuning components within circuitry 2634, for example rotary
trim capacitors (not shown) may require access after assembly,
which can be provided through openings such as holes 2611 drilled
through laminate 2610 in FIG. 20, or holes 2612 drilled through
supporting member 2620 in FIGS. 20 and 21.
[0220] FIGS. 3A and 3B are block diagrams illustrating a preferred
embodiment of an inventory control system that uses intelligent
shelves in accordance with the present invention. As shown in FIG.
3A, each of the several intelligent shelves 501a-501n and 502a-502n
provided according to the present invention have multiple antennae
200 connected to a reader unit 120 through a single transmission
cable 222. The reader units 120 controls the activation of the
connected antennae 200 either sequentially, or simultaneously with
a phase difference, to determine item information from RFID tags
associated with respective items being inventoried. Therefore, the
reader units 120 are able to extract inventory related information
for each of the RFID tagged items stored in the respective shelves.
For simplicity, FIG. 3A shows only two groups of shelves, each
group having its own reader unit, the groups being 501a-501n and
502a-502n respectively. However, one skilled in the art would
recognize that many such groups of shelves could be a part of an
inventory control system provided by the present invention. For
example, all the shelves in one or more warehouses could be grouped
to provide hundreds or even thousands of groups of shelves that
could be connected together to form an inventory control system as
provided by the present invention.
[0221] It should be understood that while the preferred embodiment
of the inventory control system and method utilizes a multiple
antenna RFID detection system with a single transmission cable 222
corresponding to the embodiment of FIG. 6, all the other
embodiments of the multiple antenna RFID system disclosed herein
may also be used with the inventory control system and method
according to the present invention. Therefore, for example, the
RFID detection systems disclosed in FIGS. 7 and 8 may also be used
with the inventory control system and method of the present
invention. In such embodiments, for example, the unmodulated RF
system may be used first to warm up the tags before the modulated
RF system is used to extract the inventory related data from the
RFID tags.
[0222] As shown in FIG. 3A, the item information data collected by
the reader units 120 from each of the intelligent shelves 501a-501n
and 502a-502n is transmitted to an inventory control processing
unit 550. The inventory control processing unit 550 is typically
configured to receive item information from the intelligent shelves
501a-501n and 502a-502n. The inventory control processing unit 550
is typically connected to the intelligent shelves over an
electronic network 525 and is also associated with an appropriate
data store 555 that stores inventory related data including
reference tables and also program code and configuration
information relevant to inventory control or warehousing. The
inventory control processing unit 550 is also programmed and
configured to perform inventory control functions that well known
to those skilled in the art. For example, some of the functions
performed by an inventory control (or warehousing) unit include:
storing and tracking quantities of inventoried items on hand, daily
movements or sales of various items, tracking positions or
locations of various items, etc.
[0223] In operation, the inventory control system would determine
item information from the intelligent shelves 501a-501n and
502a-502n that are connected to the inventory control processing
unit 550 through an electronic network 525. In one embodiment, the
various intelligent shelves 501a-501n and 502a-502n would be under
the control of inventory control processing unit 550 that would
determine when the reader units 120 would poll the antennae 200 to
determine item information of items to be inventoried. In an
alternate embodiment, the reader units 120 may be programmed to
periodically poll the connected multiple antennae for item
information and then transmit the determined item information to
the inventory control processing unit using a reverse "push" model
of data transmission. In a further embodiment, the polling and data
transmission of item information by the reader units 120 may be
event driven, for example, triggered by a periodic replenishment of
inventoried items on the intelligent shelves. In each case, the
reader unit 120 would selectively energize the multiple antennae
connected to it to determine item information from the RFID tags
associated with the items to be inventoried.
[0224] Once the item information is received from the reader units
120 of the intelligent shelves 501a-501n and 502a-502n of the
present invention, the inventory control processing unit 550
processes the received item information using programmed logic,
code, and data at the inventory control processing unit 550 and at
the associated data store 555. The processed item information is
then typically stored at the data store 555 for future use in the
inventory control system and method of the present invention.
[0225] One skilled in the art would recognize that inventory
control processing unit 550 could be implemented on a general
purpose computer system connected to an electronic network 525,
such as a computer network, The computer network can also be a
public network, such as the Internet or Metropolitan Area Network
(MAN), or other private network, such as a corporate Local Area
Network (LAN) or Wide Area Network (WAN), or even a virtual private
network. A computer system includes a central processing unit (CPU)
connected to a system memory. The system memory typically contains
an operating system, a BIOS driver, and application programs. In
addition, the computer system contains input devices such as a
mouse and a keyboard, and output devices such as a printer and a
display monitor.
[0226] The computer system generally includes a communications
interface, such as an Ethernet card, to communicate to the
electronic network 525. Other computer systems may also be
connected to the electronic network 525. One skilled in the art
would recognize that the above system describes the typical
components of a computer system connected to an electronic network.
It should be appreciated that many other similar configurations are
within the abilities of one skilled in the art and all of these
configurations could be used with the methods and systems of the
present invention. Furthermore, it should be recognized that the
computer system and network disclosed herein can be programmed and
configured as an inventory control processing unit to perform
inventory control related functions that are well known to those
skilled in the art.
[0227] In addition, one skilled in the art would recognize that the
"computer" implemented invention described herein may include
components that are not computers per se but also include devices
such as Internet appliances and Programmable Logic Controllers
(PLCs) that may be used to provide one or more of the
functionalities discussed herein. Furthermore, while "electronic"
networks are generically used to refer to the communications
network connecting the processing sites of the present invention,
one skilled in the art would recognize that such networks could be
implemented using optical or other equivalent technologies.
Likewise, it is also to be understood that the present invention
utilizes known security measures for transmission of electronic
data across networks. Therefore, encryption, authentication,
verification, and other security measures for transmission of
electronic data across both public and private networks are
provided, where necessary, using techniques that are well known to
those skilled in the art.
[0228] Other embodiments of the invention will be apparent to those
skilled in the art from a consideration of the specification and
the practice of the invention disclosed herein. It is intended that
the specification be considered as exemplary only, with the true
scope and spirit of the invention being indicated by the following
claims.
* * * * *