U.S. patent application number 16/197631 was filed with the patent office on 2020-05-21 for system and method for modifying rfid tags.
The applicant listed for this patent is Konica Minolta Laboratory U.S.A., Inc.. Invention is credited to Randy Cruz Soriano, Kazuto Yamamoto.
Application Number | 20200160140 16/197631 |
Document ID | / |
Family ID | 70727990 |
Filed Date | 2020-05-21 |
United States Patent
Application |
20200160140 |
Kind Code |
A1 |
Soriano; Randy Cruz ; et
al. |
May 21, 2020 |
SYSTEM AND METHOD FOR MODIFYING RFID TAGS
Abstract
An RFID tag having an initial range may be modified to have a
reduced or increased range by printing a modification element over
the antenna of the RFID tag. The modification element may function
as an extension of the antenna or may function to shield the
antenna. To allow for cost-efficient modification of RFID tags,
multiple RFID tags may be secured on a substrate and modified
together.
Inventors: |
Soriano; Randy Cruz; (San
Leandro, CA) ; Yamamoto; Kazuto; (Foster City,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Konica Minolta Laboratory U.S.A., Inc. |
San Mateo |
CA |
US |
|
|
Family ID: |
70727990 |
Appl. No.: |
16/197631 |
Filed: |
November 21, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06K 19/07773
20130101 |
International
Class: |
G06K 19/077 20060101
G06K019/077 |
Claims
1. A method for modifying at least one RFID tag comprising a chip
on a first side of a substrate and an antenna configured to
transmit data from the chip, the RFID tag having an initial
transmission range, the method comprising: modifying the RFID tag
to have a modified transmission range, the modifying performed by
printing a modification element over the antenna of the RFID tag,
the modified transmission range being greater than or less than the
initial transmission range.
2. The method of claim 1, wherein the modification element
comprises metal or graphite.
3. The method of claim 1, wherein the modification element is made
of an electrically conductive material that, when printed over the
antenna, makes contact with the antenna such that the modified
transmission range is greater than the initial transmission
range.
4. The method of claim 1, wherein the modification element is made
of an electrically conductive material that, when printed over the
antenna, makes contact with the antenna or shields a portion of the
antenna from radio waves such that the modified transmission range
is less than the initial transmission range.
5. The method of claim 1, further comprising: determining the
initial transmission range before the modifying of the RFID tag, by
using a pre-modification sensor to induce a response from the RFID
tag; and determining the modified transmission range after the
modifying of the RFID tag, by using the pre-modification sensor or
a post-modification sensor to induce a response from the RFID
tag.
6. The method of claim 5, further comprising, before the modifying
of the RFID tag: comparing, by a computer, the determined initial
transmission range to a target transmission range; and determining,
by the computer, a configuration of the modification element
according to a result of the comparing of the initial transmission
range to the target transmission range, wherein the printing of the
modification element is performed according to the determined
configuration.
7. The method of claim 6, wherein: the RFID tag is associated with
a position for storing an article on which the RFID tag is to be
attached; and the method further comprises, before the comparing of
the initial transmission range to the target transmission range,
determining the target transmission range according to the position
associated with the RFID tag, the determining performed by the
computer.
8. The method of claim 1, further comprising, after the modifying
of the RFID tag: folding the first side of the substrate onto
itself such that the chip, the antenna, and the modification
element are between two portions of the substrate.
9. The method claim 8, further comprising, before the folding of
the first side of the substrate: applying a coating on the first
side of the substrate such that a bottom surface of the coating
covers and contacts the chip, the antenna, and the modification
element; and applying an adhesive on the first side of the
substrate, wherein after the folding of the first side of the
substrate, the adhesive is on a top surface of the coating.
10. The method of claim 8, wherein: the method further comprises
printing, on a second side of the substrate opposite the first
side, an image that corresponds to identification information
associated with the RFID tag, the printing performed before the
folding of the first side of the substrate; the folding of the
first side of the substrate causes the image on the second side of
the substrate to cover an area occupied by the chip, the antenna,
and the modification element on the first side of the substrate;
and the method further comprises storing the identification
information on the chip before or after the modifying of the RFID
tag.
11. The method of claim 1, wherein: the RFID tag and other RFID
tags are disposed on the first side of the substrate during the
modifying of the RFID tag, each of the other RFID tags having a
respective initial transmission range, the method further comprises
modifying each of the other RFID tags, while disposed on the first
side of the substrate, to have a respective modified transmission
range, the modifying performed by printing a respective
modification element on a respective antenna of each of the other
RFID tags, the respective modified transmission range being greater
than or less than the respective initial transmission range.
12. The method of claim 11, further comprising, after the modifying
of the RFID tag and the other RFID tags: folding the first side of
the substrate onto itself such that the RFID tag and the other RFID
tags are disposed between two portions of the substrate; and
cutting the substrate to separate each of the RFID tag and the
other RFID tags.
13. A system for modifying at least one RFID tag secured on a
substrate, the RFID tag having a chip on a first side of the
substrate and an antenna configured to transmit data from the chip,
the RFID tag having an initial transmission range, the system
comprising: a first printer configured to receive the RFID tag
secured on the substrate; and a computer configured to control the
first printer to modify the RFID tag, while secured on the
substrate, to have a modified transmission range by instructing the
first printer to print a modification element over the antenna of
the RFID tag, the modified transmission range being greater than or
less than the initial transmission range.
14. The system of claim 13, wherein the first printer is configured
to print the modification element using a material that comprises
metal or graphite.
15. The system of claim 13, wherein the first printer stores
electrically conductive material, and the computer is configured to
control the first printer to print the electrically conductive
material, as the modification element contacting the antenna, such
that modified transmission range is greater than the initial
transmission range.
16. The system of claim 13, wherein the first printer stores
electrically conductive material, and the computer is configured to
control the first printer to print the electrically conductive
material, as the modification element contacting the antenna or
shielding a portion of the antenna from radio waves, such that
modified transmission range is less than the initial transmission
range.
17. The system of claim 13, further comprising: one or more sensors
configured to induce a first response from the RFID tag before the
RFID tag is modified by the first printer, determine the initial
transmission range based on the first response, induce a second
response from the RFID tag after the RFID tag is modified by the
first printer, and determine the modified transmission range based
on the second response.
18. The system of claim 17, wherein: the computer stores a target
transmission range and is configured to compare the determined
transmission initial range to the target transmission range before
the RFID tag is modified; the computer determines a configuration
of the modification element according to a result of the comparison
of the initial transmission range to the target transmission range,
the computer controls the first printer to print the modification
element over the antenna of the RFID tag according to the
determined configuration.
19. The system of claim 18, wherein: the computer is configured to
associate the RFID tag with a position for storing an article on
which the RFID tag is to be attached; and the computer is
configured to determine the target transmission range according to
the position associated with the RFID tag, the determination being
made before the computer compares the initial transmission range to
the target transmission range.
20. The system of claim 13, further comprising: a folding mechanism
configured to fold the first side of the substrate onto itself such
that the chip, the antenna, and the modification element are
between two portions of the substrate.
Description
FIELD
[0001] This disclosure relates generally to RFID devices, more
particularly, to modification of RFID devices.
BACKGROUND
[0002] Radio frequency identification (RFID) is a technology that
works on radio frequency signals. An RFID system often comprises
three main components: (1) an RFID tag which stores data is usually
attached to an article that one desires to identify and/or track;
(2) an RFID reader that communicates with the RFID tag using radio
frequency signals to obtain data from the RFID tag; and (3) a host
data processor that uses the data obtained by the RFID reader from
the RFID tag. If the RFID tag is within range of the radio
frequency signals (radio waves), a communication link between the
two RFID devices is established and the RFID tag replies with data
to the RFID reader. Based on this reply, the RFID reader may
identify the article.
[0003] There are various types of RFID tags. Passive RFID tags do
not include a power source, such as a battery. Passive RFID tags
rely on power derived from radio waves from the RFID reader to
transmit a reply to the RFID reader. Active RFID tags include a
power source to power its internal circuitry and to enable
transmission of a reply to the RFID reader. Semi-passive RFID tags
include a power supply to power its internal circuitry but relies
on power derived from the radio waves from the RFID reader to
transmit a reply to the RFID reader.
[0004] An important factor is range, which refers to the maximum
distance between the RFID reader and RFID tag for a reliable
communication link between the two RFID devices. The range is
affected by various factors, such as background radio frequency
noise, surrounding structures that may affect the radio waves from
the RFID reader, antenna configurations of the reader and tag,
relative orientation (angle) between the reader and tag, and
carrier frequency. RFID systems may operate in different frequency
bands. In the low frequency (LF) band, a carrier frequency of 125
kHz or 134 kHz, for example, may provide a range up to 10 cm. In
the high frequency (HF) band, a carrier frequency of 13.58 MHz, for
example, may provide a range up to 1 meter. In the ultra high
frequency (UHF) band, a carrier frequency within 860-960 MHz, for
example, may provide a range up to 15 meters.
[0005] RFID tags are used on a great variety of articles. The
articles can be items of clothing for sale in a retail shop,
medical devices, and individual components used in a factory, just
to name a few. It is often the case that RFID tags manufactured in
bulk have the same range. However, articles on which the RFID tags
are attached might be stacked within a box, and the box may be
surrounded by other boxes when the RFID tags must be read by an
RFID reader. To ensure reliable communication, the RFID tags may be
over-designed or conservatively designed to work in the most
extreme situation that is expected during the useful life of the
RFID tags, but such an approach may increase costs significantly.
This scenario and others present a need for a system and method
that allows for cost-efficient modification of an RFID tag to
customize its range.
SUMMARY
[0006] Briefly and in general terms, the present invention is
directed to a system and method for modifying one or more RFID tags
to reduce or increase its range.
[0007] In aspects of the invention, a method is for modifying at
least one RFID tag comprising a chip on a first side of a substrate
and an antenna configured to transmit data from the chip, the RFID
tag having an initial range. The method comprises modifying the
RFID tag to have a modified range, the modifying performed by
printing a modification element over the antenna of the RFID tag,
the modified range being greater than or less than the initial
range.
[0008] In aspects of the invention, a system is for modifying at
least one RFID tag secured on a substrate, the RFID tag having a
chip on a first side of the substrate and an antenna configured to
transmit data from the chip, the RFID tag having an initial range.
The system comprises a first printer configured to receive the RFID
tag secured on the substrate. The system comprises a computer
configured to control the first printer to modify the RFID tag,
while secured on the substrate, to have a modified range by
instructing the first printer to print a modification element over
the antenna of the RFID tag, the modified range being greater than
or less than the initial range.
[0009] The features and advantages of the invention will be more
readily understood from the following detailed description which
should be read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a plan view showing an example RFID tag before
modification.
[0011] FIG. 2 is a plan view showing an example substrate on which
is secured the RFID tag and other RFID tags before
modification.
[0012] FIGS. 3 and 4 are plan views showing example modification
elements applied to the RFID tag to increase and decrease
range.
[0013] FIG. 5 is a diagram showing an example system for modifying
the RFID tag.
[0014] FIG. 6 is a diagram showing an example modification assembly
of the system.
[0015] FIG. 7 is a plan view showing images printed on one side of
the substrate.
[0016] FIG. 8 is a plan view showing modification elements printed
over the RFID tag on the other side of the substrate.
[0017] FIG. 9 is a plan view showing a coating and an adhesive
applied on the same side of the substrate as the RFID tags, and
showing the result after the substrate is folded.
[0018] FIG. 10 is a side view along the direction of arrows B-B in
FIGS. 3 and 9, showing an example modification element that
modifies the RFID tag.
[0019] FIG. 11 is a side view along the direction of arrows C-C in
FIG. 4, showing another example modification element that modifies
the RFID tag.
[0020] FIG. 12 is an isometric view showing an RFID read
environment for which the RFID tag may be modified according to its
expected position in the RFID read environment.
[0021] FIG. 13 is a flow diagram showing an example process for
modifying the RFID tag.
DETAILED DESCRIPTION
[0022] Referring now in more detail to the drawings for purposes of
illustrating non-limiting examples, wherein like reference numerals
designate corresponding or like elements among the several views,
there is shown in FIG. 1 example RFID tag 10 comprising chip 12 and
antenna 14 configured transmit data from the chip. Chip 12 is a
silicon device (integrated circuit) having pads that are
operatively connected to antenna 14, which is a conductive circuit.
In the illustrated example, antenna 14 is a dipole (common for UHF)
although other antenna designs are possible, such as coiled shapes
(common for HF). Circuitry provided by chip 12 may include
modulators and voltage regulators, as known in the art. Chip 12 may
have control logic that includes data encoding and decoding
functions, as known in the art. Chip 12 includes memory, which may
be an EEPROM for example, for storing information. Such information
may be associated with an article on which the RFID tag will be
attached at a later time. Chip 12 and antenna 14 are secured to a
substrate, which may be made of paper (e.g., cardstock), polymer
film, fabric, or other material.
[0023] RFID tag 10 will be modified to increase or reduce its range
by printing a modification element over antenna 14. In FIG. 1, RFID
tag 10 is in an unmodified state. That is, RFID tag 10 has not been
subjected to modification described below. While in an unmodified
state, RFID tag 10 is functional in the sense it is capable of
powering circuits of chip 12 in response radio waves from an RFID
reader. RFID tag 10 has a range, which is the maximum distance
between RFID tag 10 and an RFID reader for a for a reliable
communication link between the tag and reader.
[0024] The term "initial range" refers to the range of RFID tag 10
while in its unmodified state. By definition, an initial range is
greater than zero. The term "modified range" refers to the range of
RFID tag 10 while in its modified state, which is the state
resulting from modification by printing a modification element over
antenna 14. The modification element includes metal or graphite,
for example. The modification element can have a maximum thickness
up to 0.13 mm (about 5 mil) or up to 0.25 mm (about 10 mil), for
example.
[0025] The range of the RFID tag may be affected by variations in
background radio frequency noise (electromagnetic interference),
surrounding structures, and other conditions. Thus, the initial
range may be determined by testing before RFID tag 10 is modified,
such as by using a particular sensor using a known frequency and
power under known test conditions (e.g., known amount of background
RF noise, known orientation (angle) between reader and tag, etc.).
For example, the sensor used for this purpose may be an RFID reader
or other type of sensor.
[0026] Various test techniques may be used to determine the initial
and modified ranges. In a technique referred to herein as position
thresholding, the distance of the sensor from RFID tag 10 is
adjusted while the sensor emits radio waves. The distance is
adjusted until the radio waves induce RFID tag 10 to send a
response to the sensor, or until the sensor detects a backscatter
signal from the RFID tag. In a technique referred to herein as
signal thresholding, the position of the sensor may be fixed
(sensor does not move relative to the RFID tag) while
characteristics of the radio waves from the antenna of the sensor
are adjusted. The radio wave characteristics are adjusted until the
radio waves induce RFID tag 10 to send a response to the sensor, or
until the sensor detects a backscatter signal from the RFID tag.
The radio wave characteristics that result in the response may be
used, in formulas and models known in the art, to calculate a value
of the initial range.
[0027] The initial range is relative to the modified range, which
may be determined by testing after RFID tag 10 is modified. Signal
thresholding, position thresholding, or other test technique may be
used to determine the modified range. For position thresholding,
the sensor and test conditions to determine the modified range may
be the same as or similar to those used to determine the initial
range.
[0028] As indicated above, the range of RFID tag 10 depends on a
variety of factors. Thus, values for the initial and modified
ranges may vary depending on the sensor used for testing. For
example, when using one type of sensor under certain test
conditions, the initial and modified ranges may be 1.2 meters and 2
meters, respectively. When using another type of sensor under
different test conditions, the initial and modified ranges may be
1.5 meters and 2.1 meters, respectively. The initial and modified
ranges may be based on multiple tests, and the results of the tests
may be averaged to determine initial and modified ranges.
[0029] As shown in FIG. 2, substrate 16 may carry RFID tag 10 and
other RFID tags 10' in unmodified states. Other RFID tags 10' may
be identical to or different from RFID tag 10. In this way,
multiple RFID tags may be modified together for efficiency.
Modification involves printing modification element 18 over antenna
14, as shown in FIGS. 3 and 4. Modification element 18 is made of
an electrically conductive material. The conductive material for
modification element 18 may be the same or similar material that
was used to form antenna 14. For example, the conductive material
may be a conductive ink or a conductive paste containing metal
particles and/or graphite particles.
[0030] In FIG. 3, modification element 18 has been printed over
antenna 14 in such a way that modification element 18 makes
electrical contact with antenna 14 and increases the range of RFID
tag 10. Electrical contact allows modification element 18 to
function as an extension of antenna 14. The modified range is
greater than the initial range. The modified range may be at least
20% or at least 30% greater than the initial range. In the
illustrated example, modification element 18 enlarges antenna 14.
Modification element 18 increases the length of antenna 14.
Modification element 18 may increase the power gain of antenna 14.
The gain is expressed relative to an ideal isotropic antenna or
relative to a dipole antenna used as a reference, and may be
measured using techniques known in the art.
[0031] As previously mentioned, the RFID tag may have a coil shaped
antenna. If the RFID tag has a coil shaped antenna, modification
element 18 may increase or decrease the number of coil loops in the
antenna.
[0032] In FIG. 4, modification element 18 has been printed over
antenna 14 in such a way that modification element 18 decreases the
range of RFID tag 10. The modified range is less than the initial
range. The modified range may be at least 20% or at least 30% less
than the initial range. Modification element 18 makes electrical
contact with antenna 14 such that the number of bends in the
antenna 14 are effectively reduced, or modification element 18 does
not make electrical contact with antenna 14 such that a portion of
antenna 14 is shielded from radio waves by modification element 18.
An insulation layer (e.g., layer 70 of FIG. 11) may exist between
modification element 18 and antenna 14 to prevent electrical
contact. For example, modification element 18 may decrease the
power gain of antenna 14.
[0033] FIG. 5 shows example system 20 for increasing or reducing
the range of RFID tag 10. System 20 includes computer 22,
modification assembly 24, and server 26. These elements of system
20 communicate via network 28. For example, network 28 may be local
area network, wide area network, and/or the Internet. Computer 22
may be a tablet computer, laptop computer, desktop computer, or
workstation computer.
[0034] Alternatively, computer 22 and/or server 26 may be
integrated into and form parts of modification assembly 24. Server
26 may be integrated into and form part of computer 22.
[0035] In further aspects, system 20 includes RFID tag 10 secured
on substrate 16. System 20 may include RFID tag 10 and other RFID
tags 10' secured on substrate 16.
[0036] As shown in FIG. 6, modification assembly 24 includes media
tray 30, image printer 32 (second printer), pre-modification sensor
34, modification printer 36 (first printer), post-modification
sensor 38, coating mechanism 40, bonding mechanism 42, folding
mechanism 44, cutting mechanism 46, and conveyor assembly 48. Media
tray 30 holds substrate 16 before RFID tag 10 is modified. Conveyor
assembly 48 (depicted as a dotted line) extends through
modification assembly 24 and includes motors, guides, and rollers,
as are known in the art. Conveyor assembly 48 takes substrate 16
from media tray 30 and then conveys substrate 16 across or through
image printer 32, pre-modification sensor 34, modification printer
36, post-modification sensor 38, coating mechanism 40, bonding
mechanism 44, and folding mechanism 44.
[0037] In alternative aspects, modification assembly 24 includes
RFID tag 10 secured on substrate 16. Modification assembly 24 may
include RFID tag 10 and other RFID tags 10' secured on substrate
16.
[0038] In alternative aspects, any of image printer 32,
pre-modification sensor 34, post-modification sensor 38, coating
mechanism 40, bonding mechanism 44, folding mechanism 44, and
cutting mechanism 46 may be separated from modification assembly 24
while remaining as part(s) of system 20. That is, any of image
printer 32, pre-modification sensor 34, modification printer 36,
coating mechanism 40, bonding mechanism 44, folding mechanism 44,
and cutting mechanism 46 may be present outside of modification
assembly 24.
[0039] In alternative aspects, any of image printer 32,
pre-modification sensor 34, post-modification sensor 38, coating
mechanism 40, bonding mechanism 44, folding mechanism 44, and
cutting mechanism 46 may be eliminated from system 20.
[0040] Conveyor assembly 48 conveys substrate 16 from media tray 30
to image printer 32 (second printer). Image printer 32 prints an
image on the second side of substrate 16. The printed image may be
text and/or graphics, such as a machine-readable barcode. Image
printer 32 may use electrostatic, ink-jet, stamping, roller, or
other technique to print the image. Structures for these techniques
are known in the art and need not be described herein.
[0041] FIG. 7 shows example image 50 printed by image printer 32 on
second side 16S of substrate 16. Image 50 corresponds to RFID tag
10, as will become apparent from the folding step described below.
When other RFID tags 10' are on the first side of substrate 16,
image printer 32 prints other images 50' corresponding to other
RFID tags 10'. Image 50 and other images 50' may be identical, or
they may be different from each other. The images 50, 50' are
confined to lower half 16L of substrate 16.
[0042] Referring again to FIG. 6, conveyor assembly 48 conveys
substrate 16 from image printer 32 to pre-modification sensor 34.
Pre-modification sensor 34 is used to conduct a test to determine
the initial range of RFID tag 10 in an unmodified state.
Pre-modification sensor 34 emits radio waves W1 toward RFID tag 10
during the test. Position thresholding, signal thresholding, or
another test technique may be used to determine the initial range.
Pre-modification sensor 34 may be an RFID reader. RFID readers and
sensors for this purpose are known in the art need not be described
herein.
[0043] Next, conveyor assembly 48 conveys substrate 16 from
pre-modification sensor 34 to modification printer 36 (first
printer). Modification printer 36 prints modification element 18
over antenna 14. For example, modification printer 36 may print
modification element 18 as described for FIG. 3 or FIG. 4.
Modification printer 36 may use electrostatic, ink-jet, stamping,
rolling, or other technique. Structures for these techniques are
known in the art and need not be described herein.
[0044] FIG. 8 shows example modification element 18 printed by
modification printer 36 (first printer) on first side 16F of
substrate 16. Modification printer 36 printed modification element
18 over the antenna of RFID tag 10. Modification printer 36 also
printed modification elements 18' over respective antennas of other
RFID tags 10'. Modification element 18 and modification elements
18' may be identical, or they may be different from each other.
Note that the RFID tags are confined to upper half 16U of substrate
16.
[0045] Referring again to FIG. 6, conveyor assembly 48 conveys
substrate 16 from modification printer 36 (first printer) to
post-modification sensor 38. Post-modification sensor 38 is used to
conduct a test to determine the modified range of RFID tag 10.
Post-modification sensor 38 emits radio waves W2 toward RFID tag 10
during the test. Position thresholding, signal thresholding, or
another test technique may be used to determine the modified range.
Post-modification sensor 38 may be an RFID reader. RFID readers and
sensors for this purpose are known in the art need not be described
herein.
[0046] In alternative aspects, post-modification sensor 38 is
eliminated, and pre-modification sensor 34 is used to determine the
modified range of RFID tag 10. For example, conveyor assembly 48
may return substrate 16 to pre-modification sensor 34, or
pre-modification sensor 34 may be configured to move on a track to
a position downstream of modification printer 36.
[0047] Next within FIG. 6, conveyor assembly 48 conveys substrate
16 from post-modification sensor 38 to coating mechanism 40.
Coating mechanism 40 applies protective coating 56 (FIG. 9) on
first side 16F of substrate 16 such that a bottom surface of
coating 56 covers and contacts the chips, antennas, and
modification elements of all RFID tags on substrate 16. Coating 56
may be a thin film that protects the underlying electronic
components from moisture, salt, chemicals, temperature changes, and
other conditions that may damage the components. Coating 56 may be
applied as a wet substance that is dried by coating mechanism 40.
When dried, coating 56 may function as an electrical insulator
and/or a moisture barrier. Coating 56 may be applied as a dry
polymer film that functions as an electrical insulator and/or a
moisture barrier. Coating mechanism 40 may use spraying, brushing,
stamping, dipping, rolling, or other technique to apply coating 56.
Structures for these techniques are known in the art and need not
be described herein.
[0048] In FIG. 9, coating 56 is illustrated as having been
partially removed so that some of the RFID tags are visible for
purposes of discussion herein. It is to be understood that coating
56 covers all the RFID tags.
[0049] Referring again to FIG. 6, conveyor assembly 48 conveys
substrate 16 from coating mechanism 40 to bonding mechanism 42.
Bonding mechanism 42 applies adhesive 58 on first side 16F of
substrate 16. In FIG. 9, adhesive 58 is confined to lower half 16L
of substrate 16. Bonding mechanism 42 may apply adhesive 58 as a
wet or tacky substance. Bonding mechanism 42 may use spraying,
brushing, stamping, rolling, or other technique to apply adhesive
58. Structures for these techniques are known in the art and need
not be described herein.
[0050] Next, conveyor assembly 48 conveys substrate 16 from bonding
mechanism 42 to folding mechanism 44. Folding mechanism 44 folds
first side 16F of substrate 16 onto itself as indicated by arrow A.
Folding mechanism 44 folds substrate 16 in half. Note that images
50, 50' (FIG. 0.7) are at lower half 16L of the substrate, and RFID
tags 10, 10' are on upper half 16U of the substrate. Thus, when
folding mechanism 44 folds substrate 16, image 50 on second side
16S of the substrate covers area 60 occupied by RFID tag 10
(including chip 12 and antenna 14) and modification element 18 on
first side 16F of the substrate, as shown in FIG. 10. That is, RFID
tag 10 and its associated image 50 become aligned. Similarly, each
of the other RFID tags 10' and its associated image 50' become
aligned.
[0051] Next, conveyor assembly 48 conveys substrate 16 from folding
mechanism 44 to cutting mechanism 46. Cutting mechanism 46
separates each of RFID tag 10 and other RFID tags 10' by cutting
substrate 16 along dotted lines L in FIG. 9. Cutting mechanism 46
include a blade or cutting die for cutting along dotted lines
L.
[0052] In alternative aspects, conveyor assembly 48 may not extend
to cutting mechanism 46. Conveyor assembly 48 may terminate at any
one of image printer 32 (second printer), pre-modification sensor
34, modification printer 36 (first printer), post-modification
sensor 38, coating mechanism 40, bonding mechanism 44, and folding
mechanism 44. After the point of termination, a person may convey
substrate 16 to the next part of modification assembly 24.
[0053] In alternative aspects, pre-modification sensor 34 is not
located between image printer 32 and modification printer 36.
Instead of the location shown in FIG. 6, pre-modification sensor 34
is located before (upstream of) coating mechanism image printer 32.
For example, pre-modification sensor 34 may be located between
image printer 32 and media tray 30.
[0054] In alternative aspects, post-modification sensor 38 is not
located between modification printer 36 and coating mechanism 40.
Instead of the location shown in FIG. 6, post-modification sensor
38 may be located after (downstream of) coating mechanism 40. For
example, post-modification sensor 36 may be located after cutting
mechanism 46.
[0055] FIG. 10 is a partial side view in the direction of arrows
B-B in FIGS. 3 and 9. FIG. 10 shows a possible configuration of a
modified RFID tag after substrate 16 is folded. Modification
element 18, chip 12, and antenna 14 are between two portions 16A,
16B of substrate 16. Bottom surface 56B of coating 56 covers and
contacts modification element 18, chip 12, and antenna 14. Adhesive
58 is on top surface 56T of coating 56. Adhesive 58 keeps the
modified RFID tag sealed and protected between two portions 16A,
16B of substrate 16. Image 50 on second side 16S of substrate 16
covers area 60 occupied by modification element 18, chip 12, and
antenna 14 on first side 16F of substrate 16.
[0056] In alternative aspects, coating 56 contacts modification
element 18 but does not contact chip 12 and antenna 14, as shown in
FIG. 11. FIG. 11 is a partial side view in the direction of arrows
C-C in FIG. 4. FIG. 11 shows a possible configuration of a modified
RFID tag after substrate 16 is folded. FIG. 11 is the same as FIG.
10 except for the presence of insulation layer 70, which covers and
contacts chip 12 and antenna 14. Insulation layer 70 may be a thin
film that protects the underlying electronic components from
moisture, salt, chemicals, temperature changes, and other
conditions that may damage the components. Insulation layer 70 may
be present when substrate 14 is placed in media tray 30, or a
mechanism (similar to coating mechanism 40) may be present between
media tray 30 and modification printer 36 for the purpose of
applying insulation layer 70. Modification element 18 is printed
over antenna 14, though there is no conductive path from
modification element 18 to antenna 14 because of insulation layer
70. Absence of a conduct path allows modification element 18 to
shield a portion of antenna 14 from radio waves from an RFID
reader. Thereafter, coating mechanism 40 applies coating 56 over
modification element 18, chip 12, and antenna 14. Bottom surface
56B of coating 56 contacts modification element 18 but does not
contact chip 12 and antenna 14 because of insulation layer 70.
[0057] Referring again to FIG. 5, computer 22 includes processors
and memory that allow it to execute computer readable instructions
for controlling modification assembly 24 and for performing
processes described below.
[0058] Pre-modification sensor 34 (FIG. 6) is configured to
determine the initial range (Ri) of RFID tag 10, as described
above. Computer 22 stores a target range (Rt) and is configured to
compare the determined initial range to the target range before
instructing modification printer 36 (first printer) to print
modification element 18. Computer 22 is configured to determine a
configuration of modification element 18 according to a result of
the comparison. Thereafter, computer 22 controls modification
printer 36 to print modification element 18 over antenna 14 of RFID
tag 10 according to the determined configuration.
[0059] TABLE I is an example lookup table that may be stored in
computer 22 and which computer 22 uses to determine a configuration
of modification element 18. The lookup table shows a relationship
between additional range (R) and additional antennal length (L) for
a particular type of RFID tag having a particular antenna
configuration and chip. In this example, computer 22 calculates the
additional range from Equation 1 below.
R=Rt-Ri (Eq. 1)
An equation other than Equation 1 may be used to determine R. For
example, weighting or correction factors "a" and "b" may be applied
according to Equation 2 below.
R=(aRt)-(bRi) (Eq. 2)
[0060] The additional range (R) represents a comparison of the
initial range (Ri) and target range (Rt). The lookup table may be
developed empirically from many tests performed before the RFID tag
is modified. Computer 22 may store many tables, each table being
for a particular type of RFID tag. Computer 22 may receive
information on the type of RFID tag. In response, computer 22
matches the received information to one of the lookup tables,
applies the value of R to the lookup table to determine a value for
L. In this way, computer 22 determines L, which represents the
configuration of modification element 18.
[0061] In alternative aspects, the lookup table may come from the
database of server 26. For example, computer 22 may transmit
information on the type of RFID tag to server 26, and server 26
matches the information to one of the lookup tables stored in its
database, and then transmits the lookup table or a value for L to
computer 22.
TABLE-US-00001 TABLE I Additional Range, R Additional Antenna
Length, L -1 meter -10 mm 1 meter 20 mm 2 meters 30 mm 3 meters 60
mm
[0062] In alternative aspects, the relationship between R and L for
a particular type of RFID tag may be in a theoretical or empirical
model (equation), instead of a lookup table. Several models may be
stored in the database of server 26. For example, computer 22 may
transmit a value for R and information on the type of RFID tag to
server 26. In response, server 26 matches the information to one of
the models stored in its database, applies the value of R to the
model to calculate a value for L, and transmits the value for L to
computer 22. In this way, computer 22 determines L, which
represents the configuration of modification element 18.
[0063] For example, if the target range is Rt=7 meters and the
initial range is Ri=4 meters, then computer 22 may compute the
additional range as R=7-4=3 meters according to Equation 1. Using a
lookup table or model, computer 22 determines the configuration of
modification element 18 to be L=60 mm. Thereafter, computer 22
instructs modification printer 36 to print modification element 18
as a conductive trace that provides 60 mm additional length to the
pre-existing length of antenna 14. In addition to or as an
alternative to length, the lookup table (or model) may include
other characteristics for the configuration of modification element
18. Other characteristics include without limitation: width for
printing the conductive trace, the number of meanders or bends of
the conductive trace, the number of loops formed by the conductive
trace (potentially for an RFID tag having a pre-existing coil
design for inductive coupling), the thickness of the trace, and the
area size of a paddle tip at the end of the trace (potentially for
an RFID tag having a pre-existing coil design for backscatter
coupling).
[0064] In another example, if the target range is Rt=3 meters and
the initial range is Ri=4 meters, then computer 22 may compute the
additional range as R=3-4=-1 meter according to Equation 1. Using a
lookup table or model, computer 22 determines the configuration of
modification element 18 to be L=-10 mm. The negative value means
that the effective length of the antenna of the RFID tag should be
reduced by 10 mm. Thereafter, computer 22 instructs modification
printer 36 to print modification element 18 as a radio wave shield
that covers a 10 mm length of antenna 14. In addition to or as an
alternative to length, the lookup table (or model) may include
other characteristics for the configuration of modification element
18. Other characteristics include without limitation: the number of
meanders or bends to be covered by modification element 18, and the
number of loops to be covered by modification element 18. Thus, for
example, computer 22 may instruct modification printer 36 to print
modification element 18 that reduces the number or bends or loops
in antenna 14.
[0065] The target range may be manually entered into or transmitted
to computer 22. The target range may be specified by a customer.
The target range may be constant (the same) for all RFID tags on
substrate 14, in which case the printed configuration of
modification element 18 may be identical for all the RFID tags on
substrate 14. The target range may vary among the RFID tags on
substrate 14, in which case the printed configuration of
modification element 18 may vary among the RFID tags on substrate
14.
[0066] As shown in FIG. 12, it may be possible for RFID tags to be
placed in different environments. FIG. 12 shows boxes 74 (articles)
on which RFID tags are to be secured. Boxes 74 may be stored on a
pallet and transported together from a manufacturing facility to
retail facility, for example. To track individual boxes 74 during
transportation, the entire group may be passed across an RFID
screening station having one or more RFID readers 76. Thus, the
target range for a particular RFID tag may be based on the expected
environment in which that RFID tag is intended to encounter. RFID
tags near the center of the group of boxes may require a greater
target range compared to boxes that are closer to the RFID reader.
The greater target range may account for the increased distance
from the RFID reader and/or interference caused by boxes that
surround the RFID tags near the center.
[0067] Referring again to FIG. 2, computer 22 is configured to
associate RFID tag 10 with a position for storing an article on
which RFID tag 10 is to be attached. The position of the article is
relative to other articles (e.g., boxes 74 that surround the RFID
tag) or relative to an RFID reader to be used later on the RFID tag
10 (e.g., RFID reader 76). Computer 22 is configured to determine
the target range according to the position associated with the RFID
tag.
[0068] TABLE II is an example lookup table that may be stored in
computer 22. Computer 22 uses the lookup table to determine the
target range according to the position associated with the RFID
tag. The lookup table shows a relationship between the position and
the target range (Rt). The lookup table may be developed
empirically from many tests performed on identical RFID tags before
the present RFID tag is modified. Computer 22 may store many lookup
tables, each lookup table being for a particular RFID reading
environment. For example, the lookup table of TABLE II may be used
for the RFID reading environment of FIG. 12, and another lookup
table may be used for a different RFID reading environment.
TABLE-US-00002 TABLE II Position Target Range, Rt 1. Facing RFID
reader 2 meters 2. All other positions 5 meters 3. Center region of
group of boxes 6 meters
[0069] For example, computer 22 may associate RFID tag 10 and all
other RFID tags 10' to Position 3, in which case computer 22
determines that target range Rt should be 6 meters. Thereafter,
computer 22 determines the configuration of modification element 18
according to Rt, as previously described. That is, computer 22
computes R using Rt and Ri, and then determines configuration
characteristic L (and/or other configuration characteristics) from
R. Applying Ri=4 meters to Equation 1 gives R=6-4=2 meters.
Applying R=2 meters to the lookup table of TABLE I, computer 22
determines the configuration of modification element 18 to be L=30
mm for all the RFID tags on substrate 14.
[0070] In another example, computer may associate other RFID tags
10' to Position 2, in which case computer 22 determines that target
range Rt should be 5 meters. Applying Ri=4 meters to Equation 1
gives R=5-4=1 meter. Applying R=1 meter to the lookup table of
TABLE I, computer 22 determines the configuration of modification
element 18 to be L=20 mm for other RFID tags 10'.
[0071] FIG. 13 shows an example process for modifying an RFID tag
(e.g., RFID tag 10 described above). The process may begin at block
92, where modification element (e.g., modification element 18
described above) is printed over the antenna of an RFID tag.
Optionally, the process may begin at block 80 by printing image 50
on the substrate (e.g., substrate 14), and then the process goes to
block 92 where the modification element on the other side of the
substrate.
[0072] Optionally, the configuration for the modification element
may be determined at block 88, and then the modification element is
printed at block 92 according to the determined configuration.
Optionally, the configuration may be determined by determining the
initial range (Ri) of the RFID tag at block 82, for example by
using pre-modification sensor 34. Next, Ri is compared to Rt at
block 86, and then the configuration for the modification element
is determined at block 88 according to a result of the comparison.
The determined configuration may specify whether the modification
element should make electrical contact with the antenna of the RFID
tag. If there should be electrical contact, the process may proceed
to block 92 to print the modification element. If there should be
no electrical contact, the process may proceed to block 90 to apply
an insulation layer (e.g., layer 70) over the antenna (if an
insulation layer is not already present), and then proceed to block
92 to print the modification element.
[0073] The target range (Rt) may be predetermined. If Rt is not
predetermined, Rt may be determined at block 84 according to a
position associated with the RFID tag. The position may be for an
article (e.g., box 74) on which the RFID tag is to be secured
later. The position of the article may be relative to an RFID
reader (e.g., RFID reader 76) and/or relative to other articles.
Thereafter, the process proceeds to blocks 86, 88, 90, and 92 as
previously described.
[0074] After the modification element is printed, a coating (e.g.,
coating 56) is applied on the modification element at block 96. The
coating may contact the chip and/or antenna of the RFID tag if an
insulation layer is not present on the chip and/or antenna.
[0075] Optionally at block 98, an adhesive (e.g., adhesive 58) is
applied on the substrate. Next at block 100, the substrate is
folded so that the chip, the antenna, and the modification element
are disposed between two portions of the substrate. Thereafter, the
substrate may be cut at block 102. If multiple RFID tags are
present on the substrate, cutting will separate the RFID tags from
each other.
[0076] Optionally, the modified range of the RFID tag may be
determined at block 94 after the modification element is printed.
This may be performed for quality control purposes. For example,
post-modification sensor 38 may to determine the modified range. In
alternative aspects, block 94 may be moved directly after any of
blocks 96, 98, 100, and 102. In alternative aspects, the modified
range of the RFID tag may be performed while the RFID tag is
secured to an article (e.g., box 74), and an RFID reader (e.g.,
RFID reader 76) may be used to confirm that the modified range of
the RFID tag is sufficient.
[0077] FIGS. 1-4 and 8-11 show one type of passive RFID tag. It is
contemplated that other types of passive RFID tags may be modified
according to the method and system described herein. It is also
contemplated that modification of range by printing a modification
element may be formed for semi-passive and active RFID tags.
[0078] While several particular forms of the invention have been
illustrated and described, it will also be apparent that various
modifications may be made without departing from the scope of the
invention. It is also contemplated that various combinations or
subcombinations of the specific features and aspects of the
disclosed embodiments may be combined with or substituted for one
another in order to form varying modes of the invention.
Accordingly, it is not intended that the invention be limited,
except as by the appended claims.
* * * * *