U.S. patent application number 09/792239 was filed with the patent office on 2001-08-30 for optical scanner with controller subsystem.
Invention is credited to Bubnoski, David P., Knowles, Carl H., Rockstein, George B., Wilz, David M..
Application Number | 20010017321 09/792239 |
Document ID | / |
Family ID | 46251916 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010017321 |
Kind Code |
A1 |
Knowles, Carl H. ; et
al. |
August 30, 2001 |
Optical scanner with controller subsystem
Abstract
A portable automatic code symbol reading system having a laser
scanning engine that provide hands-free automatic laser scanning
capabilities. The automatic code symbol reading system includes a
self-contained power supply aboard its housing, and a
power-conserving control subsystem for conserving the consumption
of electrical power during automatic portable laser scanning
operations. The control subsystem of the present invention has a
plurality of control centers which control the operation of the
system components in accordance with preselected system control
operations. Each of the control centers is responsive to control
activation signals generated by certain of the system components
upon the occurrence of predefined conditions. Certain of the
control centers are capable of overriding other control centers to
provide diverse control capabilities. These control capabilities
facilitate execution of intelligent functions and power consumption
measures required during automatic, hands-free code symbol reading
operations.
Inventors: |
Knowles, Carl H.;
(Moorestown, NJ) ; Rockstein, George B.; (Audubon,
NJ) ; Wilz, David M.; (Sewell, NJ) ; Bubnoski,
David P.; (Mariton, NJ) |
Correspondence
Address: |
Steven R. Bartholomew, Esq.
60 East 42nd Street, 41st Floor
New York
NY
10165
US
|
Family ID: |
46251916 |
Appl. No.: |
09/792239 |
Filed: |
February 23, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09792239 |
Feb 23, 2001 |
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09444694 |
Nov 22, 1999 |
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6223987 |
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09444694 |
Nov 22, 1999 |
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08489305 |
Jun 9, 1995 |
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08489305 |
Jun 9, 1995 |
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08821917 |
Mar 18, 1997 |
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5868572 |
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08821917 |
Mar 18, 1997 |
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07583421 |
Sep 17, 1990 |
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5260553 |
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08821917 |
Mar 18, 1997 |
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07580740 |
Sep 11, 1990 |
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Current U.S.
Class: |
235/462.44 |
Current CPC
Class: |
G06K 7/10792 20130101;
G06K 7/10693 20130101; G06K 2207/1012 20130101; G06K 7/10702
20130101; G06K 7/10871 20130101; G06K 7/10584 20130101; G06K
7/10673 20130101; G06K 7/10881 20130101; G06K 7/109 20130101; G06K
7/10564 20130101; G06K 7/10 20130101; G06K 2007/10534 20130101;
G06K 7/10891 20130101; G06K 7/10811 20130101; G06K 7/10594
20130101; G06K 2207/1017 20130101; G06K 2207/1016 20130101; G06K
7/14 20130101; G06K 7/10663 20130101; G06K 2207/1018 20130101; G06K
7/10801 20130101; G06K 17/0022 20130101; G06K 7/10851 20130101;
G06K 7/10603 20130101; G06K 7/1443 20130101; G06K 7/10861
20130101 |
Class at
Publication: |
235/462.44 |
International
Class: |
G06K 007/10 |
Claims
What is claimed is:
1. An automatic bar code symbol reading system, comprising: a
mounting/conveying mechanism for: (a) affixing the scanning engine
to the body of a user, and/or (b) permitting conveyance of the
scanning engine from place to place; a housing having a light
transmission aperture through which visible light can exit and
enter said housing, and being operably connected to said
mounting/conveying mechanism so that said light transmission
aperture is orientable in a scanning direction; an object detection
mechanism in said housing, for detection of an object located
within at least a portion of a scan field defined external to said
housing and extending along said scanning direction, and
automatically generating a first activation signal indicative of
the detection of said object in at least a portion of said scan
field; a scan data producing mechanism in said housing, for
producing scan data from said detected object located in said scan
field, said scan data producing mechanism including a laser beam
producing mechanism for producing and projecting a laser beam
through said light transmission aperture, and repeatedly scanning
said laser beam across said scan field and a bar code symbol on
said detected object, and A laser light detecting mechanism for
detecting the intensity of laser light reflected off said bar code
symbol and passing through said light transmission aperture, and
for automatically producing scan data indicative of said detected
intensity; a bar code symbol detection circuit for processing
producing scan data so as to detect said detected object, and
automatically generate a second activation signal in response to
the detection of said bar code symbol; a programmed microprocessor
operably associated with said bar code symbol detection circuit,
for processing produced scan data, when activated, so as to decode
said detected bar code symbol and automatically produce symbol
character data representative of said decoded bar code symbol;
system control circuitry for automatically activating said
programmed microprocessor in response to the generation of said
second activation signal, and automatically deactivating said
programmed microprocessor in response to said programmed
microprocessor failing to produce symbol character data within a
predetermined time period; and a self-contained power supply for
supplying electrical power to said object detection mechanism, said
scan data producing mechanism, said bar code symbol detection
circuit, said programmed microprocessor, and said system control
circuitry.
2. The portable automatic bar code symbol reading system of claim
1, wherein said bar code symbol has first and second envelope
borders, and said bar code symbol detection circuit detects said
bar code symbol by detecting said first and second envelope
borders.
3. The portable automatic bar code symbol reading system of claim
1, wherein said object detection mechanism comprises a signal
transmitter for transmitting a signal into said scan field, and a
signal receiver for receiving said transmitted signal reflected off
said object in at least a portion of said scan field, and
automatically generating said first activation signal in response
to receiving said transmitted signal.
4. The portable automatic bar code symbol reading system of claim
1, wherein said signal transmitter comprises an optical source for
transmitting a pulsed infra-red, visible, or ultraviolet light
signal, and wherein said signal receiver comprises an optical
detector and an optical element for focusing reflected light pulses
onto said light detector.
5. The portable automatic bar code symbol reading system of claim
1, which further comprises a radio frequency transmitter,
supportable on the body of said user, for transmitting said symbol
character data to a peripheral device.
6. The portable automatic bar code symbol reading system of claim
1, wherein said mounting/conveying mechanism comprises a glove
wearable about the hand of said user.
7. The portable automatic bar code symbol reading system of claim
6, wherein said glove allows a finger of said user to be exposed
when worn about the hand thereof.
8. The portable automatic bar code symbol reading system of claim
1, wherein said laser beam producing mechanism comprises a laser
diode for producing a visible laser beam.
9. The portable automatic bar code symbol reading system of claim
1, wherein said scanning direction is oriented along the pointing
direction of the fingers of said operator.
10. A automatic code symbol reading system, comprising: a
mounting/conveying mechanism wearable on the body of an operator; a
housing having a light transmission aperture through which visible
light can exit and enter said housing, and being mechanically
coupled to said mounting/conveying mechanism so that said light
transmission aperture is orientable in a scanning direction; an
object detector in said housing, for detection of an object located
within at least a portion of a scan field defined external to said
housing and extending along said scanning direction, and
automatically generating a first activation signal indicative of
the detection of said object in at least a portion of said scan
field; a scan data producing mechanism in said housing, for
producing scan data from said detected object located in said scan
field, said scan data producing mechanism including a laser beam
source for producing and projecting a laser beam through said light
transmission aperture, a laser beam scanning mechanism for
repeatedly scanning said laser beam across said scan field and a
code symbol on said detected object, and a laser light detector for
detecting the intensity of laser light reflected off said code
symbol and passing through said light transmission aperture, and
for automatically producing scan data indicative of said detected
intensity; a code symbol detection circuit for processing produced
scan data so as to detect said code symbol on said detected object,
and automatically generate a second activation signal in response
to the detection of said code symbol; a programmed microprocessor
associated with said code symbol detection circuit, for processing
produced scan data, when activated, so as to decode said detected
code symbol and automatically produce symbol character data
representative of said decoded code symbol; system control
circuitry for automatically activating said programmed
microprocessor in response to the generation of said second
activation signal, and automatically deactivating said programmed
microprocessor in response to said programmed microprocessor
failing to produce symbol character data within a predetermined
time period; and a self-contained power supply mechanism for
supplying electrical power to said object detection mechanism, said
scan data producing mechanism, said bar code symbol detection
circuit said programmed microprocessor, and said system control
circuitry.
11. The automatic code symbol reading system of claim 10, wherein
said code symbol has first and second envelope borders, and said
code symbol detection circuit detects said code symbol by detecting
said first and second envelope borders.
12. The automatic code symbol reading system of claim 10, wherein
said object detector comprises a signal transmitter for
transmitting a signal into said scan field, and a signal receiver
for receiving said transmitted signal reflected off said object in
at least a portion of said scan field, and automatically generating
said first activation signal in response to receiving said
transmitted signal.
13. The automatic code symbol reading system of claim 12, wherein
said signal transmitter comprises an optical light source for
transmitting pulsed optical (infra-red, visible, and/or
ultraviolet) energy, and wherein said signal receiver comprises an
optical detector and an optical element for focusing reflected
optical pulses onto said optical detector.
14. The automatic code symbol reading system of claim 10, which
further comprises a radio frequency transmitter, supportable on the
body of said operator, for transmitting said symbol character data
to a peripheral device.
15. The portable code symbol reading system of claim 10, wherein
said mounting/conveying mechanism comprises a glove wearable about
the hand of said operator.
16. The automatic code symbol reading system of claim 15, wherein
said glove allows the finger of said operator to be exposed when
worn about the hand thereof.
17. The automatic code symbol reading system of claim 10, wherein
said laser beam source comprises a laser diode for producing a
visible laser beam.
Description
RELATED CASES
[0001] This is a Continuation of patent application Ser. No.
09/444,694 filed on Nov. 22, 1999, which is a Continuation of
patent application Ser. No. 08/489,305 filed Jun. 9, 1995, now
abandoned, which is a continuation of application Ser. No.
08/821,917 filed Jan. 16, 1992, now abandoned, which is a
continuation-in-part of application Ser. No. 07/583,421 filed Sep.
17, 1990, now U.S. Pat. No. 5,260,553, and application Ser. No.
07/580,740 filed Sep. 11, 1990, now abandoned, each of which is
incorporated herein by reference.
FIELD OF INVENTION
[0002] This invention relates generally to optically-based bar code
symbol reading systems, and more particularly to an automatic bar
code symbol reading system having a laser scanning engine with
novel control circuitry.
BRIEF DESCRIPTION OF THE PRIOR ART
[0003] Various types of optical scanners are in use and have been
disclosed in the relevant literature. Many of these scanners read
bar codes, such as the Uniform Produce Code (UPC), which are
imprinted on products, labels affixed to products, or packaging for
products.
[0004] One type of existing scanner is referred to as a slot
scanner. Typically, slot scanners are mounted beneath or at the
checkout counter of a retail establishment, such as a supermarket.
Another type of scanner is a hand-held scanner. This type of
scanner typically includes a grip portion held in one's hand to
enable the scanner to be directed onto a bar code so that the scan
pattern produced by the scanner traverses the bar code symbol in
order to read it.
[0005] In the last few years there has been increased development
toward making hand-held scanners extremely small and lightweight.
One such scanner is disclosed in my U.S. Pat. No. 4,930,848, which
disclosure is incorporated by reference, and which is assigned to
the Assignee of the present invention. That scanner comprises a
hand grip portion and a body portion. Within the body portion of
the scanner is an "laser scanning engine" having all of the
necessary optical, mechanical and electrical components required to
produce a laser beam scanning pattern for reading bar codes and for
receiving light reflected therefrom to produce an electrical signal
indicative thereof. Other hand-held laser scanners are disclosed in
the patent literature, including U.S. Pat. Nos. 4,387,297 (Swartz,
et al.), 4,409,470 (Swartz, et al.), 4,460,120 (Swartz, at al.),
4,607,156 (Koppenall, et al.). 4,706,248 (Swartz, et al.), and
4,575,625 (Knowles).
[0006] Although prior art hand-held scanners are capable of reading
bar code symbols, they all typically require that they be held in
the hand of the user so that the laser beam scanning pattern can be
aimed at the bar code symbol. In the course of checking out
customers' purchases at a checkout counter, a clerk is thus
required to continually pick up the scanner, direct its laser beam
onto the symbols to effect the reading of the symbols, and then
either lay down the scanner between readings or between customers
or place it in a support cradle or mount so that the clerk can use
his or her hands for other purposes.
[0007] Thus, there is a great need in the art for a bar code symbol
reading system that offers the features of a hand-held system,
while enabling hands-free triggerless operation.
OBJECTS OF THE INVENTION
[0008] Accordingly, a general object of the present invention is to
provide an automatic bar code symbol reading system having a laser
scanning engine of compact, lightweight construction, and which
overcomes the disadvantages of prior art systems.
[0009] It is a further object of the present invention to provide a
compact, lightweight bar code symbol reading system which allows
the hands of the user to be free when the scanner is in use.
[0010] It is still a further object of this invention to provide a
compact, lightweight bar code symbol reading system having a small
laser scanning engine mountable to the body of the user for
producing a laser scanning pattern during hands-free operation.
[0011] It is still a further object of this invention to provide a
bar code symbol reading system having a portable or body mountable
laser scanning engine which is connected to a processing unit which
may be mounted on the body of the user or on some other
structure.
[0012] It is still another further object of this invention to
provide a compact, lightweight bar code symbol reading system which
is portable or body-mountable and which automatically initiates
operation of the laser scanner engine when the laser scanner engine
is brought close to an object with a coded symbol to be read.
SUMMARY OF THE INVENTION
[0013] These and other objects of the subject invention are
achieved by providing an automatic bar code symbol reading system
for reading coded symbols, e.g., UPC symbols, etc.
[0014] In the illustrative embodiment, the system comprises a laser
scanning engine for producing a laser scanning pattern and a remote
unit coupled thereto. The laser scanning engine includes a
mounting/conveying mechanism for: (a) mounting the scanning engine
on the body of the user, e.g., on the wrist, head, etc, and/or (b)
for conveying the scanning engine from place to place. The user may
position the laser scanning engine on his or her body so that the
laser scanning pattern produced thereby is directed toward and
traverses the coded symbol to be read. The laser scanning engine is
operably connected to the remote unit via a communications
mechanism. In the illustrative embodiment, the remote unit includes
electrical means for processing and decoding the signals received
from the laser scanning engine and producing symbol character data
representative of the symbols read. The remote unit may be also
mounted on the body of the user or on some stationary support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The objects and advantages of the present invention will be
readily appreciated by reading the following Detailed Description
of the Illustrated Embodiment in conjunction with the accompanying
drawings, wherein:
[0016] FIG. 1 is a perspective view of an automatic portable bar
code symbol reading system constructed in accordance with the
present invention and comprising a laser scanning engine shown
mounted on a wrist of a user and with a remote unit connected
thereto by way of a cable;
[0017] FIG. 2 is an enlarged sectional view of the laser scanner
engine taken along with line 2-2 of FIG. 1;
[0018] FIG. 3 is a side elevational view of one typical use of the
system of the present invention, namely, a user seated at a counter
with the laser scanning engine mounted on the user's wrist while
the remote unit is mounted either on the user's body or
alternatively at the counter;
[0019] FIG. 4 is a block functional system diagram of the automatic
bar code symbol reading system of the present invention,
illustrating the principal components of the system integrated
within the control system thereof;
[0020] FIG. 5 is a logical function diagram of the first control
means of the control system of the present invention;
[0021] FIG. 5A is a block functional diagram of a first embodiment
of the system activation means of the automatic bar code symbol
reading system of the present invention;
[0022] FIG. 5B is a block functional diagram of a second embodiment
of the system activation means of the automatic bar code symbol
reading system of the present invention;
[0023] FIG. 6 is a block functional diagram of the bar code
presence detection means of the automatic bar code symbol reading
system of the present invention;
[0024] FIG. 7 is a logical functional diagram of the first control
means of the control system of the present invention;
[0025] FIG. 8 is a logical function diagram of the second control
means of the control system of the present invention;
[0026] FIG. 9A is a functional block diagram of the third control
means of the control system of the present invention;
[0027] FIG. 9B is a flow chart of a control program carried out in
the third control means for the case of system-control operation
No. 2 (i.e., path option 2) of the illustrative embodiment;
[0028] FIGS. 10A, 10B and 10C, taken together, show a high level
flow chart illustrating three user-selectable courses of programmed
system operation that the control system of the illustrative
embodiment may undergo;
[0029] FIG. 11 is a state diagram illustrating the various states
that the bar code symbol reading system of the illustrative
embodiment may undergo during the course of its operation;
[0030] FIG. 12 is a side elevational view of the automatic bar code
symbol reading system of FIG. 1, showing the laser scanning engine
affixed to a glove worn on the user's hand, with the remote unit
held in a holster or on a belt worn on the waist of the user;
[0031] FIG. 13 is an elevational view of the automatic bar code
symbol reading system of FIG. 1, showing the laser engine mounted
on-a hat worn on the user's head; and
[0032] FIG. 14 is an elevational view of the automatic bar code
symbol reading system of FIG. 1, showing the laser engine mounted
on a headband worn on the user's head.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
[0033] Referring now in greater detail to the drawings, where like
characters refer to like parts, the laser-based bar code symbol
reading system of the present invention is shown in FIG. 1.
[0034] As illustrated, bar code symbol reading system 102 comprises
a laser scanning engine 104 and a remote unit 110 connected
together by way of a cable 108. The laser scanning engine 104 is
preferably constructed in accordance with the teachings of my
aforementioned U.S. Pat. No. 4,930,848 and my co-pending U.S.
patent application Ser. No. 299,998, filed on Jan. 23, 1989,
entitled Laser Scanner Engine with Folded Beam Path, and my
co-pending U.S. patent application Ser. No. 07/300,018, filed Jan.
23, 1989, entitled Bouncing Oscillating Scanning Device for Laser
scanning Apparatus, all of which are assigned to the same Assignee
of this invention, and whose disclosures are incorporated thereon
by reference.
[0035] The laser scanning engine disclosed in application Ser. No.
07/299,988 is an extremely compact and lightweight devise. That
device includes beam sweeping means, constructed in accordance with
the teachings of my co-pending application Ser. No. 07/300,018, for
sweeping for laser beam through an arc to form a linear single line
scanning pattern. The laser scanning engine is contained within a
housing 112 which also includes various optical components for
folding and forming laser beam path downstream of the beam sweeping
means so as to increase the focal length of the beam, and thereby
allow for a smaller beam scan angle then otherwise possible with
such a compact housing. Thus features enable accurate and reliable
reading of coded symbols located close to and substantially far
away from the laser scanning engine 104. The beam sweeping means
includes an oscillating mirror system constructed in such a manner
so that the speed of oscillations is substantially linear between
reversals instead of the sinusoidal speed variation exhibited by
prior art oscillating mirror devices.
[0036] As shown in FIG. 1, the laser scanning engine 104 is
arranged for convenient mounting on a portion of the body Of the
user, e.g., on the wrist of a user by way of a strap 106. The cable
108 serves to carry the electrical signal produced by the laser
scanning engine (and which is representative of the bar code) to
the remote unit 110 where the signal is processed, e.g., decoded.
Electrical power for the laser scanning engine is also provided
from the remote unit 110 by way of cable 108.
[0037] As shown in FIG. 2, the laser scanning engine 104 includes a
semi-conductor laser diode 116 with an associated focusing means
118 for producing a focused laser light beam 120. The laser light
beam 120 is projected within the housing 112 of the laser scanning
engine onto a beam sweeping mechanism 134 (constructed in
accordance with the teachings of my patent application Ser. No.
07/300,018). The beam sweeping-mechanism includes a planar mirror
122 which is oscillated back and forth to sweep the laser beam 120
through an arc to thereby create the laser scan line 114 when
projected onto a surface. The line is ultimately projected out of
the window 111 of the engine for traversing the bar code symbol to
be read.
[0038] In order to fold the swept laser beam within the housing
downstream of the beam sweeping means, i.e., between the beam
sweeping means and window 111, the laser scanning engine also
includes the beam folding means constructed in accordance with the
teachings of my application Ser. No. 299,988. Thus, as can be seen,
the laser beam is first directed from the scanning or oscillating
mirror 122 onto a stationary mirror 124 mounted on the front end
wall 112A of the housing 112. The stationary mirror 124 reflects
the beam upward to a mirror 126 fixedly mounted on the rear end
wall 12D of the housing. The mirror 126 is angled slightly downward
so that the reflected beam is directed generally horizontally
within the housing out through the window 111 in the front end wall
112A to create a linear scan line 114 when projected on a planar
surface, e.g., a surface bearing a bar code.
[0039] The light reflected back from the bar code passes through
the window 111 where it is received by mirror 126 and reflected
back to mirror 124 and from there to the oscillating mirror 122.
The oscillating mirror reflects the received light back to a fixed
collecting mirror 128. The fixed collecting mirror 128 includes a
spherical concave surface for focusing received light onto a
phototransistor 130. The phototransistor 130 converts the reflected
light into an electrical signal indicative thereof and provides
that signal by way of cable 108 to the remote unit 110.
[0040] As the laser scanning engine of the illustrative embodiment
operates according to retroflective design principles, with its
collecting mirror 128 located between the laser diode 116 and the
scanning mirror 122, it therefore includes an opening or hole 132
in collecting mirror 128 in order to enable the outgoing laser beam
to pass therethrough to the beam sweeping (oscillating) mirror
122.
[0041] In FIG. 3, the bar code symbol reading system is shown
arranged for use in one typical application. In this application,
the system is worn by a clerk or other person at a checkout counter
of a store, at a checkout counter of a library, or some other
venue. In particular, the laser scanning engine 104 is mounted on
the wrist of the clerk by way of strap 106. In order to scan a bar
code symbol, all that is necessary is for the clerk to hold up his
or her arm with the laser scanner engine supported thereon so that
the light transmission window 111 of the laser scanning engine is
directed toward the bar code symbol, whereupon the laser beam
pattern 114 is projected onto the bar code symbol to be read. This
action leaves the operator's hands free for other purposes. The
laser light reflected back from the bar code symbol passes through
light transmission window 111, through the beam folding optics, the
oscillating mirror and the collecting mirror to the phototransistor
which converts the received light into an electrical signal
indicative of the scanned bar code symbol. The produced electrical
signal is provided by way of cable 108 to the remote unit 110 for
processing in a conventional manner.
[0042] As shown in FIG. 3, the remote unit 110 comprises a housing
in which its operational components, e.g., circuit boards, power
supply, etc., are located. The remote unit 110 may be worn on a
belt 137 or disposed in a holster (not shown) located on the waist
of the user. Alternatively, the remote unit 110 may be mounted at
the counter 116 itself. This alternative embodiment is shown by the
phantom lines drawn in FIG. 3.
[0043] In general, remote unit 110 employs components and performs
functions which are well known in the bar code symbol reading art.
In the illustrative embodiment, remote unit 110 includes signal
processing and decoding circuitry for processing the electrical
signal received from the laser scanning engine into an electrical
signal containing the information of the coded symbol (i.e., symbol
character data). This signal may be stored in the remote unit for
later retrieval, or may be passed on to some piece of peripheral
equipment 142, such as a cash register, a computer, or any other
terminal by way of any suitable means (not shown), e.g., an RS232
port. As shown in FIG. 3, remote unit 110 may also include an RF
transceiver 141 for transmitting the processed electrical signal,
e.g., symbol character data associated with the decoded symbol, to
peripheral equipment such as a host computer, or data collection
device 142.
[0044] Inasmuch as the bar code symbol reading system of FIGS. 1
and 3 is completely portable, the remote unit 110 also includes a
power supply, e.g., a battery 143, for supplying electrical power
to the laser scanning engine 104 by way of the cable 108.
[0045] It should by noted that no trigger or other hand operated
device is required to activate or deactivate the automatic bar code
symbol reading system of the present invention. An energy
transmitter and receiver and associated circuitry of the kind
disclosed in U.S. patent application Ser. No. 07/583,421 for a
"Method and Apparatus for Automatically Reading Bar Code Symbols",
filed on Sep. 17, 1990, now U.S. Pat. No. 5,260,553 and whose
disclosure is incorporated herein, say be used to automatically
activate the automatic bar code symbol reading system hereof. This
aspect of the present invention is best appreciated with reference
to the system of FIGS. 4 to 11, described below.
[0046] As shown in FIG. 4, bar code symbol reading system 102
comprises a number of system components, namely, system activation
means 2, scanning means 3 (e.g., mirror 122 and motor 134),
photoreceiving means 4 (e.g., collecting mirror 122 and
photoreceiver 130), bar code presence detection means 5,
analog-to-digital (AID) conversion means 6, symbol decoding means
7, data format conversion means 8, symbol character data storage
means 9, and data transmission means 10. As illustrated in FIG. 4,
these system components are embedded within a programmable control
system having a unique architecture which provides a great degree
of versatility in system capability and operation, as well as power
conservation. The structure, function and advantages of this
control system architecture will be described in great detail
hereinafter.
[0047] The control system of the present invention comprises
essentially three major components, namely first control means
(C.sub.1) 11, second control means (C.sub.2) 12, and third control
means (C.sub.3) 13. As will be described in greater detail
hereinafter, second control means 12 is capable of "overriding"
(i.e., exhibit and/or enable) first control means 11, whereas third
control means 13 is capable of overriding second control means 12
and first control means 11. As shown in FIG. 4, such control
override functions are carried out by the generation of control
override signals (i.e., C.sub.1 /C.sub.2, C.sub.1 /C.sub.3, and
C.sub.2 /C.sub.3) transmitted between respective control
structures.
[0048] As illustrated in FIG. 1, battery power supply 143 in remote
unit 110 provides the requisite electrical power to each of the
system components of FIG. 4, when and for time prescribed by the
control system hereof. Typically, an on/off power switch or
functionally equivalent device will be provided external to housing
112 to permit the user to empower the automatic bar code symbol
reading system. When power switch is initially engaged to its ON
position, power will only be provided to system activation means 2
to enable its operation, while, for example, only biasing voltages
and the like are provided to all other system components so that
they are each initially disabled from operation.
[0049] In accordance with the present invention, the purpose of
system activation means 2 is to produce first control activation
signal A.sub.1 upon determining (i.e., detecting) the presence of
an object (e.g., product, document, etc.) within the scan field of
bar code symbol reading device 1. In turn, first control activation
signal A.sub.1 is provided as input to both first and third control
means 11 and 13, respectively. In FIGS. 5A and 5B, two different
approaches to generating first control activation signal A.sub.1
are disclosed.
[0050] In FIG. 5A, a passive technique is illustrated, in which
passive detection of ambient light within the scan field is
performed in order to determine if an object is present within the
scan field 114 of the automatic bar code symbol reading system 1.
As illustrated in FIG. 5A, passive ambient light detection circuit
2A comprises a pair of photo diodes 15A and 15B, which sense
ambient light gathered from two different parts of the scan field
in front of the light transmission window 111 of housing 112, using
focusing lenses 16A and 16B, respectively. The output signals of
photodiodes 15A and 15B are converted to voltages by
current-to-voltage amplifiers 17A and 17B respectively, and are
provided as input to a differential amplifier 18. The output of
differential amplifier 18 is provided as input to a sample and hold
amplifier 19 in order to reject 60 and 120 Hz noise. Output signal
of amplifier 19 is provided as input to a logarithmic amplifier 20
to command signal swing. The output signal of logarithmic amplifier
20 is provided as input to a differentiator 21 and then to a
comparator 21. The output of comparator 21 provides first control
activation signal A.sub.1.
[0051] In FIG. 5B, an active technique is illustrated in which an
infrared signal is transmitted out into the scan field and first
control activation signal A.sub.1 is generated upon receiving a
reflection of the transmitted signal off an object within the scan
field. As illustrated in FIG. 5B, infrared object detection circuit
2B comprises a synchronous receiver/transmitter 22, which includes
an infrared LED 23 which generates a 900 nanometer pulsed signal at
a rate of 2.0 KHZ. This pulsed signal is transmitted through
focusing lens 23 to illuminate the scan field. When an object is
present within the scan field, a reflected pulse signal is produced
and focused through focusing lens 24 onto photodiode 25. The output
of photodiode is converted to a voltage by current-to-voltage
amplifier 26, and the output thereof is provided as input to
receiver/transmitter 22, to synchronously compare the received
signal with the transmitted signal and determine if an object is
present in the scan field. If so, then synchronous
receiver/transmitter 22 produces first control activation signal A.
sub.1=1 indicative of such condition. First control activation
signal A.sub.1=1, upon being generated, activates first control
means 11 which, in turn, enables operation of scanning means 3,
photoreceiving means 4, and bar code presence detection means 5, as
will be described in greater detail hereinafter. In order to
conserve power and improve signal-to-noise ratio at photoreceiving
means 4 during scan data collection operations, it is preferable
for first control means 11 to generate and provide a disable signal
E.sub.0 to infrared object detection circuit 2B whenever first
control means 11 enables the scanning means 3.
[0052] As illustrated in FIGS. 4 and 7, first control means 11 is
preferably realized by a circuit capable of generating enabling
signals E.sub.1, E.sub.2 and E.sub.3 for the scanning means,
photoreceiving means and bar code presence detection means,
respectively. As will be described in detail hereinafter, the
specific operation of first control means 11 is dependent on the
state of three sets of input signals, namely, first control
activation signal A, C.sub.1 override signals from C.sub.2 (i.e.,
C.sub.1 /C.sub.2 inhibit signal and C.sub.1 /C.sub.2 enable
signal), and C.sub.1 override signals from C.sub.3 (i.e., C.sub.1
/C.sub.3 inhibit signal and C.sub.1 /C.sub.3 enable signal). As
shown, first control activation control signal A.sub.1 is provided
to the "START" input of timer 28 upon which it produces a "high"
output signal for a first predetermined time period (i.e., T.sub.1
seconds). Preferably, time period T.sub.1 is selected to be about
0.3 seconds.
[0053] As illustrated in FIG. 7, the output signal of timer 28 is
provided as an input to AND gate 29, with its other input connected
to the RESET input of timer 28. The output of AND gate 29 is
provided as an input to each of OR gates 30, 31 and 32. The C.sub.1
/C.sub.2 inhibit signal from second control means 12 and the
C.sub.1 /C.sub.3 inhibit signal from third control means 13 are
provided as inputs to NOR gate 33, whereas C.sub.1 /C.sub.2 enable
signal from second control means 12 and the C.sub.1 /C.sub.3 enable
signal from third control means 13 are provided as inputs to OR
gate 34. As shown, the output signal of OR gate 34 is provided to
the other input of OR gates 30 and 31, whereas the output signal
from NOR gate 33 is provided as input to AND gate 29. The C.sub.1
/C.sub.3 enable signal is also provided as input to OR gate 32, to
complete the description of the circuit realization of first
control means 11. As indicated in FIG. 7, the outputs of OR gates
30, 31 and 32 provide enable signals E.sub.1, E.sub.2 and E.sub.3
for the scanning means, photoreceiving means and bar code presence
detection means, respectively. Notably, disable signal E.sub.0 is
produced from the output of OR gate 30.
[0054] As illustrated in FIGS. 2 and 4, scanning means 3 comprises
a light source 116 which, in general, may be any source of intense
light suitably selected for maximizing the reflectively from the
object. In the preferred embodiment, light source 116 comprises a
solid-state visible laser diode (VLD) which in driven by a
conventional driver circuit 37. As shown in FIGS. 2 and 4, the
laser beam output from laser diode 116 is swept over scan field 114
(having a predetermined spatial extent in front of front portion of
housing 112), by scanning mirror 122 being oscillated back and
forth by stepper motor 134 in response to being driven by a
conventional driver circuit 40, as shown. To selectively activate
both laser light source 116 and motor 134, the scanning means
enable signal E.sub.1 is provided as an input to both driver
circuits 37 and 40. When enable signal E.sub.1 is a logical "high"
level (i.e., E.sub.1=1), scanning means 3 is operable, a laser beam
is generated and scanned across the scan field, and scan data is
thereby produced off any object residing within the scan field.
[0055] In a conventional manner, when an object, such as product
bearing a bar code symbol, is within the scan field at the time of
scanning, the laser beam incident thereon will be reflected
producing a laser light return signal of variable intensity which
represents a spatial variation of light reflectivity characteristic
of the spaced apart pattern of bars comprising the bar code symbol.
Photoreceiving means 4 is provided for the purpose of detecting at
least a portion of laser light of variable intensity, which is
reflected off the object and car code symbol within the scan field.
Upon such detection, photoreceiver 130 produces an analog data
signal D.sub.1 indicative of the detected light intensity. In
general, scan data collection optics, namely focusing mirrors 122,
124, 126, and 128, focus scan data signals for subsequent detection
by photoreceiver 130. Photoreceiver 130, in turn, produces an
analog signal indicative of the intensity of the scan data signal,
which is subsequently amplified by preamplifier 43 to produce
analog scan data signal D.sub.1. In combination, scanning means 3
and photoreceiving means 4 operate to generate scan data from the
scan field, over time intervals specified by first control means 11
during normal (i.e., noncontrol-override) modes of operation, and
by third control means 13 during "control override" modes of
operation. As will illustrated hereinafter, this scan data is used
by both bar code presence detection means 5 and symbol decoding
means 6.
[0056] As illustrated in FIG. 4, analog scan data signal D.sub.1 is
provided as input to both bar code presence detection means 5 as
well as A/D conversion means 6. The primary purpose of bar code
presence detection means 5 is to determine whether a bar code is
present in or absent from the scan field, over time intervals
specified by first control means 11 during normal modes of
operation and by third control means 13 during control override
modes of operation. When the presence of a bar code symbol in the
scan field is determined, the bar code presence detection means 5
generates second control activation signal A.sub.2 (i.e.,
A.sub.2=1) which is provided as input to second control means 12,
as shown in FIG. 4.
[0057] As illustrated in FIG. 6, bar code presence detection means
5 is provided with enable signal E.sub.3 which is used to enable
circuitry employed in the realization of the bar code presence
detection means. In the preferred embodiment, bar code presence
detection means 5 is realized as a bar code envelope detector
circuit which processes analog scan data signal D.sub.1 so as to
produce a signal, the intensity of which indicates the general
envelope of a bar code within the scan field. Upon such detection,
bar code envelope detection circuit 5 produces second control
activation signal A.sub.2=1 which is provided as input to second
control means 12.
[0058] As shown in FIG. 6, analog scan data signal D.sub.1 is
provided as input to a differentiator 44 comprising capacitance
element C.sub.1 and resistive element R.sub.1, to produce the first
derivative signal of signal D.sub.1. The first derivative signal is
then amplified by a differential output amplifier 45, to produce as
output amplified positive and negative first derivative signals,
which in turn are provided as input to a positive peak detector 46.
The output signal of positive peak detector 46 is provided as input
to a comparator 47 which generates positive and negative bar code
detect (BCD) signals.
[0059] As illustrated in FIG. 6, the positive and negative BCD
signals are then provided as input and RESET signals to both
integrators 48A and 48B. Positive BCD signal is also provided as
input to pulse generator 50, which generates pulses upon the
detection of the negative edges of the positive BCD signal. As
shown, the output signals of integrators 48A and 48B are provided
as first inputs to comparitors 49A and 49B respectively, whereas an
envelope border threshold voltage V.sub.1 and bar code threshold
voltage V.sub.2 are provided as second inputs to comparitors 49A
and 49B, respectively. Boarder voltage V.sub.1 is a DC reference
voltage whose value can be determined on the basis of the time
constant of intergrater 48A, its gain, and the time duration of the
minimum required "boarder width" of the bar code symbol. Bar code
threshold V.sub.2 is also a DC reference voltage whose value can be
determined on the basis of the time constant of intergrater 48B,
its gain, and the time duration of the minimum required "bar code
length".
[0060] The output of comparitors 49A and 49B are provided to the
"S" gates of latches 51 and 52, respectively, and the "Q" gates of
these latches are provided as inputs to AND gate 53, as shown in
FIG. 6. The output of AND gate 53 is provided as input to the "S"
gate of latch 54, whereas the "R" gate of latch 54 is connected to
the "R" gate of latch 51. The output of pulse generator 50 is
provided as input to the "R" gate of latch 52. The output of latch
54 provides second control activation signal A.sub.2, which in
turn, is provided as input to second control means 12, as shown in
FIG. 4. The operation of the bar code envelope detector 5 is
essentially as follows. If the output signals of both comparitors
49A and 49B go "high" before the next REST pulse from pulse
generator 50 is provided to latch 52, then the output of latch 54
will go "high" (i.e., A.sub.2=1) indicating that a bar code is
present in the scan field.
[0061] In general, when the presence of a bar code in the scan
field is detected, second activation control signal A.sub.2 is
generated, second control means 12 is activated and first control
means 11 is overridden by second control means 12 through the
transmission of control override signals (i.e., C.sub.1 /C.sub.3
inhibit and C.sub.1 /C.sub.2 enable signals) from the second
control means.
[0062] As illustrated in FIG. 8, second control means 12 preferably
includes a timing means 55 whose output signal remains high for a
second predetermined time period T.sub.2. Preferably, time period
T.sub.2 is selected to be about 1.0 seconds. Second control
activation signal A.sub.2 is provided to the start input of timing
means 55, while the output thereof is provided as an input to AND
gate 56, as shown. Third control means 13 provides a pair of
C.sub.2 override signals (i.e., C.sub.2 /C.sub.3 A and C.sub.2 /B),
as input to second control means 12, as shown in FIG. 4. The
C.sub.2 /C.sub.3 inhibit signal is provided to the second input of
timing means 55. The C.sub.2 /C.sub.3 enable signal, on the other
hand, is provided to the first input of OR gates 57 and 58, whereas
the output of AND gate 56 is provided as second input to each of OR
gates 57 and 58. As illustrated in FIG. 8, the output signal of
timing means provides both C.sub.1 /C.sub.2 inhibit and C.sub.1
/C.sub.2 enable signals, whereas the output of OR gates 57 and 58
provides enable signals E.sub.4 and E.sub.5 for enabling A/D
conversion means 6 and symbol decoding means 7, respectively.
[0063] Upon detecting the presence of a bar code symbol in the scan
field, second control activation signal A.sub.2 activates second
control activation means 12, which, in turn, directly enables A/D
conversion means 6 and symbol decoding means 7 by enabling signals
E.sub.4 and E.sub.5, respectively. Indirectly, second control means
12 enables scanning means 3 and photoreceiving means 4 and disables
bar code presence detection circuit 5 by providing C.sub.1 override
signals to first control means 11.
[0064] A/D conversion means 6 can be realized by any conventional
A/D circuit or chip known in the bar code symbol reading unit, and
functions to convert analog scan data signal D into a digital scan
data signal at corresponding to the detected intensity of laser
light collected and detected at photoreceiving means 4. The
digitized scan data signal D.sub.2 is provided as input to symbol
decoding means 7, which scan line by scan line, decodes processes
in a conventional manner, the stream of digitized scan data. The
decoding means 7 processes a scan line of the digital scan data at
a time, in an attempt to decode a valid bar code symbol within the
second predetermined time period T.sub.2 established and monitored
by timing weans 55 of second control means 12. If decoding means 7
successfully decodes a bar code symbol within time period T.sub.2,
then symbol character data D.sub.3 (typically in ASCII code format)
is produced corresponding to the decoded bar code symbol. Thereupon
third control activation signal A.sub.3 is produced by symbol
decoding means 7 and is provided to third control means 13 to
activate the same. In response, third control means 13 provides
override control signals to first control 11 and second control
means 12, as described hereinabove.
[0065] As illustrated in FIGS. 4, 9A and 9B, third control means 13
of the illustrated embodiment generates and provides enable signals
E.sub.6, E.sub.7 and E.sub.8 to data format conversion means 8,
data storage means 9 and data transmission means 10. As shown,
symbol decoding means 7 provides symbol character data D.sub.3 to
data format conversion means 8 to convert data D.sub.3 into two
differently formatted types of symbol character data, namely
D.sub.4, and D.sub.5. Format-converted symbol character date
D.sub.4 is of the "packed data" format, particularly adapted for
efficient storage in data storage means 9. Format-converted symbol
character data D.sub.5 is particularly adapted for data
transmission to a Data Storage Device such as CMOS memory 144 in
remote unit 110. When symbol character data D.sub.4 is to be
converted into the format of the users choice based on a selected
option mode, third control means 13 generates and provides enable
signal E.sub.4 to data storage means 9, as shown in FIG. 4.
Similarly, when format converted data D.sub.3 is to be transmitted
to CMOS memory 144, the third control means 13 generates and
provides enable signal E.sub.4 to data transmission means 10, which
thereupon transmits format-converted symbol character data D.sub.3
to CMOS memory 144, by way of cable 108.
[0066] In the illustrated embodiment, third control means 13,
symbol decoding means 7, and data format conversion means 8 and
data storage means 9 are realized using a single programmable
device, such as microprocessor 63 having accessible memory and
external timing means. In this way, conventional symbol decoding
and data format conversion processing can be implemented in a
straightforward manner. As for programming microprocessor 63 to
realize third control means 13 and the control functions which it
performs in the illustrative embodiment, reference is made to FIGS.
4, 5, 6, 7A and 7B in particular. In order to illustrate the nature
of this programming and how it can be realized starting from a high
level flow chart, System-Control Operation No. 2, illustrated in
FIGS. 10A and 10B, will be used as an example.
[0067] In FIG. 9A, the third control means is shown implemented
with a timer 64 and microprocessor 63, whose input pins I.sub.1
through I.sub.4 and output pins O.sub.1 through O.sub.8 are
utilized in achieving the control functions performed during
System-Control Operation No. 2. In order to illustrate the
programmed operation of the third control means during
System-Control Operation No. 2, reference is made to FIGS. 9A and
9B of the drawings.
[0068] In FIG. 9A, the output of timer 64 is provided to input pin
I.sub.4 of microprocessor 63, whereas outputs O.sub.7 and O.sub.8
thereof are provided as start and reset signals respectively, to
timer 64 as shown. Timer 64 is selected to elapse at T.sub.3, which
preferably will be about 2-3 seconds. Notably, each input I.sub.1
through I.sub.4, output O.sub.1 through O.sub.8, control activation
signals A.sub.1 through A.sub.3, and enable signal E.sub.1 through
E.sub.4, may take on either a logical "high" value (i.e., 1), or a
logical "low" value (i.e., 0). As illustrated in FIGS. 10A and 10B,
during progression through System-Control operation No. 2, the
presence of third control activation signal A.sub.3 (i.e.,
A.sub.3=1) activates third control means 13. The presence of such
signal value at the third control means indicates a valid bar code
symbol has been decoded by symbol decoder 7. At the point of
activation of third control means 13, the possible logical
operations that may occur therewithin (illustrated in flow chart of
FIG. 9B), are dependent upon the condition of the first and second
control activation signals A.sub.1 and A.sub.2 and the input
I.sub.4 from the output of timer 64.
[0069] As illustrated in FIG. 9B, if control activation signals
A.sub.3 input at I.sub.3 is "low" (i.e., A.sub.3=0), then the
control program of the third control means returns to "start" and
once again continuously senses for the presence of third control
activation signal (i.e. A.sub.3=1). Otherwise, if third control
activation signal A.sub.3 input at I.sub.3 is high (i.e.,
A.sub.3=1), then the control program outputs O.sub.2, O.sub.3 and
O.sub.7 as high, inhibiting first and second control means 11 and
12, and starting timer (T.sub.3) 64, while toggling outputs O.sub.3
and O.sub.4 to enable data format conversion means 8 and data
storage means 9 or data transmission means 10.
[0070] Then, the control program proceeds to determine whether the
first control activation signal A.sub.1 at input I.sub.1 is absent
(i.e., A.sub.1=0), indicative of no object in scan field; if so,
then the control program resets outputs O.sub.2 and O.sub.3 to
return control to the inhibited first and second control means,
while toggling output O.sub.2 to reset timer (T.sub.3) 64.
Otherwise, if input I.sub.1 is high, indicative of an object in the
scan field, then the control program outputs O.sub.1 as high,
enabling third control means 13 to override first control means 11,
while enabling scanning means 3 photoreceiving means 4 and bar code
presence detection circuit 5.
[0071] The control program then determines whether second control
activation signal A.sub.2 at input I.sub.2 is low (i.e.,
A.sub.2=0), indicative of no bar code present in the scan field; if
so, the program resets outputs O.sub.2 and O.sub.3 to return
control to the first and second control means, while toggling
output O.sub.3 to reset timer (T.sub.3) 64. Otherwise, if second
control activation signal A.sub.2 at I.sub.2 is high (i.e.,
A.sub.2=11) indicative of a bar code present in the scan field,
then the control program progresses to determine whether the output
of timer 64 at input I.sub.4 has gone low, indicative of timer
T.sub.3 elapsing (i.e., t>T.sub.3). In this event, the control
program resets output O.sub.1 to disable scanning means 3,
photoreceiving means 4 and bar code detection means 5. If the input
at I.sub.1 is not low (i.e., A.sub. 1=1) indicative of timer 64 not
yet elapsed, then the control program continues to determine
whether the input at I.sub.2 has gone low (A.sub.2=0), indicative
that a bar code symbol is no longer in the scan field. The control
program will continue to repeat the above-described decision loop
until either the bar code symbol disappears from the scan field or
timer 64 elapses, whichever occurs first. If after timer 64 has
elapsed and output O.sub.1 has been reset, then the control program
finally enters a last decision loop, to determine if first control
activation signal A.sub.1 at input I.sub.1 has gone low, indicative
that an object is no longer in the scan field. If it has, then the
control program returns to start, as indicated in FIG. 9B.
Otherwise, until input I.sub.3 goes low, indicating that an object
no longer remains in the scan field, the control program will
continue to progress through this decision loop.
[0072] Notably, using the high level flow charts of FIGS. 10A and
8C, a control program for the third control means 13 can be
implemented in a straightforward manner for System-Control
Operation No. 3, illustrated in FIGS. 10B and 10C.
[0073] Having described the detailed structure and internal
functions of the automatic bar code symbol reading system hereof,
it is now proper at this juncture to describe the operation of its
control (sub)system, for each of the three illustrated
user-selectable System-Control Operations Nos. 1, 2, and 3.
[0074] Referring to Blocks A to G in FIGS. 10A and 10B,
Systems-Control Operation No. 1 is illustrated. Beginning at Block
A, the bar code symbol reading system is turned ON or powered-up,
which results in system activation means 2 being enabled (i.e.,
ON), while the remainder of the systems components (i.e., scanning
means 3, photoreceiving means 4, A/D conversion means 6, bar code
symbol detection circuit 5, symbol decoding means 7, data format
conversion means 8, data storage means 9 and data transmission
means 10), being disabled (i.e., OFF). At Block B, the control
system then determines whether first control means 11 detects the
presence of first control activation signal (i.e., A.sub.1=1). if
not, then the control system returns to Block A; otherwise, if so,
then as illustrated at Block C, first control means 11 directly
enables scanning scans 3, photoreceiving means 4 and bar code
presence detection circuit 5.
[0075] Then at Block D, second control means 12 detects the
presence of second control activation signal (i.e., A.sub.2=1)
within first predetermined time period T.sub. 1. If A.sub.2=1 is
not present, then the control system returns to Block A; and if so,
then as indicated at Block E, second control means 12 overrides
first control means 11 and indirectly enables scanning means 3,
photoreceiving means 4, A/D conversion means 6, and symbol decoding
means 7.
[0076] At Block F, third control means 13 then detect the presence
of third control activation signal (i.e., A.sub.3 =1) within second
predetermined time period T.sub.2. If A.sub.3=1 is not present
within T.sub.2, then the control system returns to Block A; and if
so, then as indicated at Block G, third control means 13 overrides
first and second control means 11 and 12, and indirectly enables
data format conversion means 8, and data storage means 9 or data
transmission means 10 until these functions are achieved, and
therewhile disables scanning means 3, photoreceiving means 4, A/D
conversion means 6 and symbol decoding means 7. Thereafter, as
shown in FIGS. 10A and 10B, the control system returns to Block A,
where only system activation means 2 is enabled.
[0077] Referring to Blocks A through K in FIGS. 10A and 10B,
System-Control (override) Operation No. 2 is illustrated. This
system-control operation offers the advantage of being able to
avoid multiple reading of bar code symbols due to the scanning beam
dwelling on a bar code symbol for an extended period of time.
[0078] Essentially, System-Control Operation No. 2 comprises all
but the last return operation of above-described System-Control
operation No. 1 and those additional operations represented by
Blocks G through K. After leaving Block G, third control means 13
detects the absence of first control activation signal (i.e..
A.sub.1=0); and if absent, then the control system returns to Block
A. If first control activation signal A.sub.1 is not absent but
rather present (i.e., A.sub.1=1), then third control means 13
indirectly enables through overridden first control means 11,
scanning means 3 and the photoreceiving means 4, and through
overridden second control means 12 indirectly enables A/D
conversion means 6 and bar code presence detection circuit 5.
Thereafter, at Block J, third control means 13 detects the absence
of second control activation signal (i.e., A.sub.2=0) within
predetermined time period T.sub.3. If signal A.sub.2 is absent,
then the control system returns to Block A; and if signal A.sub.2
is present (i.e., A.sub.2=1), then third control means 13 enters a
decision loop at block K. Here, third control means 13 in its
override mode continually detects the absence of the first
activation signal (i.e., A.sub.1=0), at which time the control
system returns to Block A.
[0079] Referring to Blocks A through G and H' through J' in FIGS.
10A, 10B and 10C, System-Control Operation No. 3 is illustrated.
This system-control operation offers the advantage of being able to
simply read bar code symbols in inventory applications, while
conserving battery power.
[0080] Essentially, System-Control Operation No. 3 comprises all
but the last return operation of above-described System-Control
Operation No. 1 and those additional operations represented by
Blocks H' through J'. After leaving Block G, third control means 13
enables, through overridden first control means 11, scanning means
3 in a pulsed mode of operation (by providing a pulsed enable
signal E.sub.1' to laser driver 37). At Block H', third control
means 13 also enables through overridden first control means 11,
photoreceiving means 3, and through overridden second control means
12, enables bar code presence detection circuit 5, and A/D
conversion means 6.
[0081] Thereafter at Block I', third control means 13 detects the
presence of second control activation means (i.e. A.sub.2=1) within
a fourth predetermined time period T.sub.4, determined using an
internal timer similar to timer (T.sub.3) 64 in FIG. 9A.
Preferably, the time duration of T.sub.3 is selected to be about
5-10 seconds. If signal A.sub.2 is not present but rather absent
(i.e., A.sub.2=0) , then the control system returns to Block A.
Otherwise, if signal A.sub.2 is present, then third control means
13 enables, through overridden second control means 12, symbol
decoding means 7. Thereafter, the control system returns to Block
F, shown in FIG. 10A.
[0082] Having described the operation of the control subsystem of
the bar code symbol reading system of present invention, it can
also be helpful to understand the various states that system may be
in during the course of each particular system-control operation
described above. In this regard, reference is made to FIG. 11 which
provides a state diagram for the three system-control operations of
the illustrated embodiment.
[0083] System-Control Operation No. 1 selected at option path 1,
will be considered first. As illustrated in FIG. 11, when bar code
symbol reading system is turned ON, only system activation means 2
is operative and all other system components are inoperative. This
condition is indicated by State A, in which the device seeks to
determine whether an object is An the scan field. Upon
determination of the presence of an object in the scan field, the
system will undergo State Transition B, placing the system in State
C.
[0084] In State C, the device seeks to determine within line
T.sub.1 the presence of a bar code in scan field, while under the
control of first control means 11. If no bar code symbol is
determined to present in the scan field with time period T.sub.1
then the system will undergo state transition D, returning the
device back to initial State A (indicated as "start" in FIG. 10A).
On the other hand, if a bar code symbol is determined to be present
in the scan field within time period T.sub.1, then the system will
undergo State Transition E, placing the system in State F.
[0085] In State F, the system collects bar code scan data D.sub.1
under the control of second control means 12, converts scan data
D.sub.1 into scan data D.sub.2 and decode processes this scan data,
scan-line by scan-line, in an attempt to decode a valid bar code
symbol within time period T.sub.2. If a bar code symbol is not
decoded within time period T.sub.2, then the system undergoes state
transition H, returning the device to initial State A. If an the
other hand a valid bar code symbol is decoded within time period
T.sub.2, symbol character data D.sub.3 produced, and then the
system undergoes State Transition G, placing the system in
"control-override" State I.
[0086] In State I, the system, while under control of the third
control means, converts the data format of symbol character data
D.sub.3 into either data D.sub.4 or D.sub.5 depending on whether
the converted symbol character data is to be stored or transmitted
to CMOS memory 144. Also in State I, the system either stores data
D.sub.1 in storage means 9, or transmits data D.sub.5 to CMOS
memory 144 via data transmission means 10 and cable 108, shown in
FIG. 4. After completion of the above functions, the system
undergoes State Transition J (due to user-selection of
System-Control Operation No. 1), returning the system to initial
State A, completing a full path through System-Control Operation
No. 1.
[0087] System-Control Operation No. 2, selected at option path 2,
will now be considered. From control override State I, the system
undergoes transition K, due to user-selection of System-Control
Operation No. 2, placing the system in control-override State L. In
State L, the system determines the presence of an object in the
scan field, while under the override control of third control means
13. Upon determination of the presence of an object in the scan
field, the system undergoes State Transition M, placing it into
State O. On the other hand, if no object is determined to be within
the scan field, then the system returns to initial State A.
[0088] In State 0, the system seeks to determine the presence of a
bar code symbol within the scan field, while the system is under
the control of third control means 13. If the system determines
that no bar code symbol is within the scan field, then the system
undergoes State Transition Q, returning the system to initial State
A. If on the other hand the system determines that a bar code
symbol lies within the scan field, indicative of the scanning beam
dwelling on a bar code symbol for an extended period of time, then
the system undergoes State Transition P, placing the system in
control-override State R.
[0089] In State R, the system discontinues scanning, photoreceiving
and bar code presence detection functions under the control of
third control means 13, and continues to sense the presence of the
object in the scan field until the object is removed therefrom.
When the presence of the object is no longer detected within the
scan field, then the system undergoes State Transition S, returning
the system to initial State A.
[0090] Lastly, System-Control Operation No. 3, selected at option
path 3, is now considered. From control-override State I, the
system undergoes State Transition T, due to user-selection of
System-Control Operation No. 3, placing the system in
control-override State U. In State U, scanning means 3 is enabled
in a pulsed-mode of operation under control of third control 13,
photoreceiving means 4 and bar code presence detection circuit 5
are also enabled under third control means 13, and therewhile the
system seeks to detect the presence of a bar code symbol in the
scan field within fourth predetermined time period T.sub.4. If a
bar code symbol is not detected within time period T.sub.4, then
the system undergoes State Transition V and returns to initial
State A under override control of third control means 13. If so the
other hand, the presence of a bar code symbol is detected within
time period T.sub.4, then the system undergoes State Transition W,
placing the system in control-override State X.
[0091] In State X, bar code scan data is collected scan-line by
scan-line, and each scan line of data is decode processed in order
to decode a valid bar code symbol. If a bar code symbol is decoded
within time period T.sub.2, then symbol character data D.sub.1 is
produced and the device undergoes State Transition Y, placing
system in control-override State I under the control of third
control means 13. There, symbol character data D.sub.3 is format
converted, and stored or transmitted as hereinbefore described.
Thereafter, the bar code symbol reading system returns to State U
under control of the third control means. If, however, a bar code
symbol is not decoded within time period T.sub.2, then the system
undergoes state transition Z, returning the system to State A while
under the control of third control means 13.
[0092] While the system of the present invention has been provided
with three user-selectable system-control (i.e., intelligence)
operations, additional system-control operations may be provided to
the control system hereof, in a manner as discussed
hereinabove.
[0093] Thus, in accordance with the present invention, an infrared
transmitter is powered at all times while the laser scanning engine
is turned off, and an infrared receiver and associated control
circuitry automatically detect the presence of an object within the
scan field of the laser scanning engine. The infrared receiver,
upon detecting reflected energy from the object, activates control
circuitry which activates the laser scanning beam, the laser
scanner, the laser receiver and the signal processing circuitry of
the laser scanning engine. The control system circuitry of the
present invention is used to automatically control the programmed
activation and deactivation of the processing and decoding
circuitry in remote unit 110. In order to operate the laser
scanning engine, all the user needs to do is bring the laser
scanning engine close to an object bearing a symbol to be read, and
automatically transmitted infrared energy is reflected back from
the object and detected so as to activate the laser scanning engine
and enabling the reading of the symbol.
[0094] Advantageously, the laser scanning engine and remote unit of
the present invention require only a very low level of power in the
non-scanning state, resulting in considerable power savings when a
battery is used to provide completely portable operations. This
enhances the utility of the system of the present invention by
eliminating requirement for any hand-operated trigger mechanism or
switch for the reading of bar code symbols.
[0095] In FIG. 12, there is shown an alternative application of the
system of the present invention. In that application, an inventory
clerk is shown using the system for inventory control. To that end,
the laser scanning engine 104 is shown mounted en a glove 136. With
this arrangement, the clerk wearing the glove can scan labels
affixed to bins or produces in inventory with both hands being free
to handle the inventory items. The remote unit 110 may be mounted
in the same manner as that described with reference to FIG. 3.
[0096] The bar code symbol reading system of the present invention
can also be used for "picking" applications, where, for example, a
stock clerk is assigned to retrieve a series of items held in
inventory. In such applications, the remote unit 110 preferably
includes memory 144, as indicated in FIGS. 1 and 4, into which
information identifying the items to be retrieved by the clerk can
be entered and stored. An annunciator (not shown) is included in
the remote unit 110 and coupled to is decoder circuitry so that
when a clerk scans an item and that item is decoded and matches the
code of an item stored in memory 144, an alarm or alert signal is
produced to indicate such an occurrence.
[0097] Several alternative ways of mounting the laser scanning
engine 104 for hands-free operations are shown in FIGS. 13 and 14.
For example, as shown in FIG. 13, laser scanning engine 104 is
mounted on a hat 138 worn on the user's head in a manner similar to
the mounting of a light on a miner's helmet. FIG. 14 shows laser
scanning engine 104 mounted on a headband 140 similar to the
conventional headband used by a doctor to mount a light or a
reflector thereon. One advantage of the mounting system of FIG. 14
is that when the user moves his or her head to see the symbol to be
read, the laser scanning pattern 114 is also directed to the symbol
to be read, thereby providing a somewhat automatic aiming
technique.
[0098] Without further elaboration, the foregoing will so fully
illustrate the present invention that others may, by applying
current or future knowledge, adapt the same for use under various
conditions of service. All such adaptations and modifications of
the same shall fall within the scope and spirit of the present
invention defined by the appended Claims to Invention.
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