Laser imageable RFID label/tag

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to the field of Radio Frequency Identification (RFID) tags and labels, and more particularly to particular structures of RFID tags and labels and methods of manufacturing them.

[0003] 2. General Background and State of the Art

[0004] RFID systems consist of a number of components including tags, handheld or stationary readers, data input units and system software. The tags are the backbone of the technology and come in various shapes, sizes and read ranges including thin and flexible “smart labels” which can be laminated between paper or plastic.

[0005] RFID creates an automatic way to collect information about a product, place, time or transaction quickly, easily and without human error. It provides a contactless data link, without need for line of sight or concerns about harsh or dirty environments that restrict other automatic ID technologies such as bar codes.

[0006] In addition, RFID is more than just an ID code, it can be used as a data carrier, with information being written to and updated on the tag on the fly.

[0007] RFID has been applied to hundreds of applications in dozens of key industries. Today, RFID is used for such applications as vehicle and personnel access control, automotive anti-theft systems, product and asset tracking and supply chain automation. Additional applications include payment and loyalty, personal and vehicle and personnel access control, automotive security, product and asset tracking, sports timing, livestock identification, document management and supply chain automation.

[0008] In one application RFID is used as part of a gas-station payment system using radio frequency signals to enable two-way, wireless communication between a key ring tag and a gasoline pump or counter-top reader. The desired purchase is automatically charged to a gas-station customer's credit card of choice without swiping a credit card or paying an attendant.

[0009] Prior art RFID tags and labels typically come in roll form. Some of these tags and labels include images on their surfaces. Typically the images are created using thermal transfer or direct thermal technology. This technology is preferred because the RFID circuits are not exposed to undue stress such as pressure or heat. However, there is a segment of the hard good distribution market that batch prints shipping labels via laser printers. Unlike thermal transfer technology, laser printing exposes the throughput media to pressure and heat. In this and other applications it would be desirable to be able to batch print tags or labels having RFID capabilities. There is a strong need in the art for an RFID tag or label that is imageable using laser printing.

INVENTION SUMMARY

[0010] A general object of the present invention is to provide an RFID tag or label that is imageable using laser printing without damaging the RFID circuit. Another object of the present invention is to provide a method for manufacturing such an RFID tag or label.

[0011] To achieve these goals, RFID tags and labels are produced having customized variable imprinting. Sheets of paper are used to form a simple and inexpensive structure for supporting and protecting RFID transponders. The paper structure also serves as a surface for customized variable imprinting using laser printers. The structure includes a base sheet, a cover sheet upon which a laser printer applied image is formed by passing the sheet assembly through a print path of a laser printer, and a mask sheet having at least one window. The sheets form a protective pocket within the window for protecting an electronic circuit from the heat and pressure applied by the laser printer when printing an image on the cover sheet. After printing, the structure can be separated into multiple RFID tags or labels. Identification information is transmitted from the electronic circuits inside the protective pockets to an external receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

P-0012[0012]FIG. 1 shows a perspective view of a laser printer and the sheet assemblies prior to and following passing through the printer.

P-0013[0013]FIG. 2 is a diagrammatic vertical cross-sectional view of a “protective pocket” region of an RFID tag or label.

P-0014[0014]FIG. 3 is a top-plan view of a face of an RFID tag or label sheet assembly.

P-0015[0015]FIG. 4 is an exploded perspective view of an RFID tag or label sheet assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

P-0016[0016] While the specification describes particular embodiments of the present invention, those of ordinary skill can devise variations of the present invention without departing from the inventive concept.

P-0017[0017] The present invention provides an economical and convenient method for producing radio-frequency identification (RFID) tags and labels having customized variable imprinting. Standard sheets of paper can be used to form a simple and inexpensive structure for supporting and protecting RFID transponders. At the same time, the paper structure serves as a surface for customized variable imprinting using common and inexpensive laser printers.

P-0018[0018]FIG. 1 shows imageable electronic-identification sheet assemblies <b>11</b> of the present invention both before and after being fed through a laser printer <b>13</b>. Laser printer applied images <b>33</b> are printed onto the sheet assemblies <b>11</b>. Each of the imageable electronic-identification sheet assemblies <b>11</b> is formed from a base sheet <b>15</b>, a cover sheet <b>17</b> and a mask sheet <b>19</b> (see FIGS. 2 and 4). The mask sheet <b>17</b> has one or more windows <b>21</b> formed therein. Four windows <b>21</b> are illustrated in the exploded perspective view of an RFID tag or label sheet assembly of FIG. 4.

P-0019[0019] The mask sheet <b>17</b> is bonded between the base <b>15</b> and cover sheets <b>17</b> to form one or more protective pockets <b>23</b>. In the particular embodiment illustrated in FIG. 4, the four windows <b>21</b> form four protective pockets <b>23</b>. Within each protective pocket <b>23</b> is one or more electronic circuits <b>25</b>. Each electronic circuit <b>25</b> can be fit entirely within a protective pocket. The diagrammatic vertical cross-sectional view of a “protective pocket” region of an RFID tag or label of FIG. 2 in addition to FIG. 4 illustrates a single electronic circuit <b>25</b> within each of the protective pockets <b>23</b>. The electronic circuit <b>25</b> can be, for example, an RFID transponder such as one from the Tag-it® HF-I Transponder Inlay series from TEXAS INSTRUMENTS.

P-0020[0020] The unique protective pockets <b>23</b> protect the electronic circuits <b>25</b> from the heat and pressure applied by the laser printer <b>13</b> when printing an image on the cover sheet <b>17</b>. The walls forming the windows <b>21</b> of the mask <b>19</b> absorb some of the pressure exerted by the feed rollers of the laser printer <b>13</b>. The base sheet <b>15</b> and cover sheet <b>17</b> also help to spread some of the pressure away from the electronic circuit <b>25</b>. The base sheet <b>15</b> and cover sheet <b>17</b>, in addition to the protective cavity <b>23</b>, also serve to insulate and channel away the heat of the laser printing from the electronic circuit <b>25</b>.

P-0021[0021] Within the protective pocket <b>23</b> is a transmission device <b>27</b> for communicating identification information <b>29</b> from the electronic circuit <b>25</b> to an external transceiver <b>31</b> outside the protective pocket <b>23</b>. The transmission device <b>27</b> can be a helical antenna portion of the electronic circuit <b>25</b> as illustrated in FIGS. 2 and 4. The electronic circuit <b>25</b> includes a microchip <b>35</b> electrically connected to the transmission device <b>27</b>.

P-0022[0022] The base sheet <b>15</b>, cover sheet <b>17</b> and mask sheet <b>19</b> can be of any size that can be fed through a laser printer, however, 8½×11 inch, A-4 or other standard-size paper is desirable because of lower cost and greater compatibility with standard printers and software packages used to design the laser printer applied images <b>33</b>.

P-0023[0023] The entire sheet assembly <b>11</b> should have a thickness such that it will fit through the laser printer <b>13</b> for printing the images <b>33</b>. For use with standard laser printers, a sheet assembly thickness of less than <b>15</b> (fifteen) thousandths of an inch (mils) thick is generally appropriate for enabling feeding through a laser printer. The sheet assembly can be formed using permanent adhesive <b>37</b> to bond the base sheet <b>15</b> to the mask sheet <b>19</b> and the electronic circuit <b>25</b>. In a particular embodiment, the electronic circuit <b>25</b> is formed on a mounting sheet <b>39</b> which is bonded to the base sheet <b>15</b> using the permanent adhesive <b>37</b>. The mounting sheet <b>39</b> can be made from polyester. Rubber or other types of adhesives can be used to bond the sheet assembly together.

P-0024[0024] The base sheet <b>15</b> and cover sheet <b>17</b> can be <b>20</b> pound bond paper while the mask sheet <b>19</b> can be <b>60</b> pound or <b>80</b> pound bond paper, for example. The windows <b>21</b> can be approximately 6 cm×8.5 cm. These paper thicknesses and window sizes work well to protect the electronic circuits <b>25</b> from the pressure and heat of the laser printer. Of course other paper thickness and window sizes can be used as well with electronic circuits <b>25</b> of different footprints and with different laser printers. The base sheet <b>15</b> and cover sheet <b>17</b> can also have thicknesses approximately in the range of 3-4 mils while the mask sheet <b>19</b> can have a thickness approximately in the range of 3-8 mils and preferably approximately 6 mils. The layers of adhesive <b>37</b> holding the base sheet <b>15</b> and cover sheet <b>17</b> to the mask sheet <b>19</b> and holding the electronic circuit <b>25</b> to the base sheet can be approximately 1 mil thick. The electronic circuit can be 6 mils or less high in order to fit into the protective pocket <b>23</b>. However, the height of the electronic circuit can vary in different embodiments. For example, if thinner paper is used for the base sheet <b>15</b> and the cover sheet <b>17</b> while thicker paper is used for the mask sheet <b>19</b>, then a taller electronic circuit can be used while maintaining the thickness of the sheet assembly thin enough to pass through the laser printer <b>13</b>. Similarly, using a thinner mounting sheet <b>39</b>, or not using the mounting sheet <b>39</b> at all, allows for greater height within the protective pocket <b>23</b> for utilizing a taller electronic circuit. In some embodiments the height of the electronic circuit <b>25</b>, with or without the mounting sheet <b>39</b>, can be greater than the height of the protective pocket <b>23</b>. In such a case the cover sheet <b>17</b> or base sheet <b>15</b> might bulge out slightly. Alternatively, a portion of the cover sheet <b>17</b> can be hollowed out to accommodate the microchip <b>35</b>.

P-0025[0025] In one embodiment the sheet assembly <b>11</b> is assembled by applying the adhesive <b>37</b> to the base sheet <b>15</b> and then bonding the mask sheet <b>19</b> to the to the base sheet <b>15</b>. The windows <b>21</b> are generally cut out of the mask sheet <b>19</b> prior to assembly of the sheet assembly <b>11</b>. The electronic circuits <b>25</b> can then be inserted into the windows <b>21</b> using a label applicator. Alternatively, the electronic circuits <b>25</b> can be applied to the base sheet <b>15</b> and then the mask sheet <b>19</b> can be bonded to the base sheet <b>15</b> with the windows <b>21</b> placed around the electronic circuits <b>25</b>. In either case, the cross-sectional footprint of the electronic circuit <b>25</b> can be made to fit within the window <b>21</b>. The adhesive <b>37</b> can then be applied to the cover sheet <b>17</b> and/or the mask sheet <b>19</b> and the cover sheet <b>17</b> is bonded to the mask sheet <b>19</b> so that the electronic circuits <b>25</b> are entirely enclosed within the protective pockets <b>23</b>. An adhesive-free region <b>41</b> can be formed on the inner surface of the cover sheet <b>17</b> so that adhesive does not contact the microchip <b>35</b>. Thus the electronic circuit <b>25</b> is bonded to the base sheet <b>15</b> and not to the cover sheet <b>17</b>. In other embodiments the electronic circuit <b>25</b> is bonded to both the cover sheet <b>17</b> and base sheet <b>15</b> or to the cover sheet <b>17</b> alone. The electronic circuit <b>25</b> can also be placed in the protective pocket <b>23</b> without using any adhesive to secure the electronic circuit <b>25</b>.

P-0026[0026] In embodiments such as that illustrated in FIGS. 1 and 4 utilizing multiple protective pockets <b>21</b> with multiple electronic circuits <b>25</b>, provisions are made for separating the sheet assembly <b>11</b> into multiple sub-assemblies <b>41</b> each including a protective-pocket enclosed electronic circuit <b>25</b> thereby producing separate RFID labels or tags. To this end, the sheet assembly <b>11</b> can include separation lines <b>43</b>. The separation lines <b>43</b> can be cleanly die-cut, for example, or can include cuts and ties. The separation lines <b>43</b> can be cut into the sheet assembly <b>11</b> following the adhesive bonding steps. In the embodiment of FIGS. 1, 3 and <b>4</b>, one vertical and one horizontal separation line <b>43</b> is cut all the way through the cover sheet <b>17</b>, mask sheet <b>19</b>, and base sheet <b>15</b> to separate the sheet assembly into four sub-assemblies each having a protective pocket <b>23</b> enclosed electronic circuit <b>25</b>.

P-0027[0027] The completed sheet assemblies <b>11</b> can then be passed through the printer <b>13</b> of FIG. 1 as described previously to provide customized variable imprinting on the cover sheet <b>17</b>. The laser printer <b>13</b> can print images on the sheet assembly <b>11</b> such that each of the sub-assemblies <b>41</b> has the same or images different from the other sub-assemblies <b>41</b>. FIG. 3 is a top-plan view of the sheet assembly <b>11</b> after passing through the laser printer <b>13</b>. Each of the sub-assemblies <b>41</b> has a different image printed on it. In the given example the sub-assemblies <b>41</b> are to be used on the dashboard of a vehicle and each has a different vehicle printed thereon. The particular design to be printed on the sheet assemblies <b>11</b> can be controlled through a computer associated with the laser printer <b>13</b>.

P-0028[0028] After printing, the sheet assemblies <b>11</b> are separated along the separation lines <b>43</b> to form a plurality of laser imprinted RFID labels or tags. The labels, in particular can be manufactured by adding an additional step to the above described adhesive bonding step. An additional adhesive layer can be added to the outside of the base sheet <b>15</b> along with a liner layer covering the additional adhesive layer. Thus, after separating the laser imprinted RFID labels, the liner layer can be removed from the back to expose the adhesive layer and the label can be stuck to a desired object. Alternatively, the adhesive layer and liner layer can be attached to the cover sheet <b>17</b>.

P-0029[0029] The external transceiver <b>31</b>, diagrammatically illustrated in FIG. 2, can include an antenna and a reader as is known in the art. The external transceiver <b>31</b> can also comprise a separate transmitter, receiver and reader. The external transceiver <b>31</b> sends a command <b>45</b> to the electronic circuit <b>25</b> and receives the response <b>29</b> from the electronic circuit <b>25</b>. The electronic circuit <b>25</b> serves as a transponder. The response from the electronic circuit <b>25</b> can be identification information. The identification information is stored in the microchip <b>35</b> and can be an ID code or the microchip <b>35</b> can be used as a data carrier, with information being written to and updated on the microchip <b>35</b> on the fly. It is advantageous for the microchip <b>35</b> to be a passive device so that it does not require a battery which would increase the size and weight and shorten the life of the RFID labels or tags. However, an on-board battery or other power supply can be desirable in other embodiments.

P-0030[0030] The RFID labels or tags of the present invention can be used in many applications. For example, the RFID labels or tags can be used as part of a payment system. The reader of the external transceiver <b>31</b> can communicate with a database of the identification information and corresponding customer information so that payments can be arranged between customers and the payment system.

P-0031[0031] The RFID labels or tags of the present invention can also be used as part of a security system having an indicator for notifying security personnel when the external transceiver <b>31</b> receives identification information from the RFID labels or tags.

P-0032[0032] The RFID labels or tags of the present invention can further be used in systems for such applications as product authentication, ticketing, library management and supply chain management applications by using the RFID labels or tags to transmit identification information to the system.

P-0033[0033] In yet another application, the RFID labels or tags of the present invention can be used as shipping labels or tags corresponding the laser printer applied image and the identification information provided by the microchip <b>35</b> to goods.

P-0034[0034] It is to be understood that the RFID labels or tags of the present invention are not limited to operation in the radio frequency range. They can also operate using other electromagnetic frequencies. In addition, they can use sound or different types of radiation to communicate between the protective pocket <b>23</b> and the external transceiver <b>31</b>. The present invention can also utilize additional sheets other than just the three described herein. For example, four or more sheets of paper can be used. Furthermore, the present invention can utilize materials other than sheets of paper to form the sheet assembly <b>11</b>. For example, plastic sheets can be used instead. The present invention is also not limited to use with a laser printer. Other types of printing such as ink-jet, dot-matrix or web-printing can be used instead and the protective pocket <b>23</b> can still serve to protect the electronic circuit <b>25</b>. Also, the electronic circuit <b>25</b> can be placed in the protective pocket <b>23</b> in orientations other than the orientation described above.

P-0035[0035] It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the present invention. The foregoing descriptions of embodiments of the invention have been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Accordingly, many modifications and variations are possible in light of the above teachings. It is therefore intended that the scope of the invention be limited not by this detailed description.