Abstract:
A label of the type bearing an RFID device, and removably attached to a backing liner. A cavity is formed in the label, the liner, or both. The RFID device is positioned in the cavity. If the RFID device were not placed into the cavity, but merely laminated between the label and the liner, then the RFID device would create a bulge. Processing steps which apply pressure would then apply large pressure at the bulge, perhaps damaging the RFID device.

Description:
BACKGROUND OF THE INVENTION  
       [0001]      FIG. 1  illustrates peel-off labels  3 , which are attached to a backing liner  6 , containing perforations  9  which cooperate with a tractor-feed mechanism (not shown) which can be used to move the liner  6  during manufacture, or later during printing, or both. Sandwiched between each label  3  and the liner  6  is an RFID, Radio Frequency IDentification, device  12 , together with one or more antennas  15 . The antennas can take the form of thin wires, or conductive foil. The combination of the RFID chip  12  and the antenna, when positioned between the label  3  and the liner  6 , is commonly called an “inlay.” 
         [0002]     A typical RFID device stores data, and when it receives an incoming rf interrogation signal from a transceiver, it transmits the data to the transceiver. For example, an RFID device can be attached to a shipping container, and the data may indicate (1) point of origin, (2) destination, (3) contents, and so on. RFID devices are convenient because the transceiver can retrieve the data without physically connecting with the RFID device, and also because, with some RFID devices, the transceiver can be located some distance from the RFID device.  
         [0003]     A problem can arise during manufacture of the labels  3  in  FIG. 1 .  FIG. 2  is a cross-sectional view, showing how the RFID device  12  can increase the thickness T of the label-liner combination. This increase in thickness can increase likelihood of damage to the RFID device  12  during manufacture, as will be explained with reference to  FIG. 3 .  
         [0004]      FIG. 3  is a simplified schematic of a manufacturing process where the labels  3  are attached to the liner  6 . If the RFID devices are installed at point  18 , subsequent processing steps occur. These include, for example, printing, coating, laminating, slitting, perforating, and die cutting processes. These processes can damage the RFID devices. For example, many printing processes utilize rollers which apply high pressure to the labels. Plainly, in the case of  FIG. 2 , the high pressure will be concentrated on the bump created by the RFID device  12 , and can damage the device  12 .  
         [0005]     The present invention offers a stratagem for eliminating such damage.  
       OBJECTS OF THE INVENTION  
       [0006]     An object of the invention is to provide an improved RFID label.  
         [0007]     A further object of the invention is to provide an improved process of manufacturing labels bearing RFID devices, in which damage to the devices is reduced.  
       SUMMARY OF THE INVENTION  
       [0008]     In one form of the invention, a cavity is created in a laminated stack of sheets. An RFID device is inserted into the cavity, thereby incorporating the RFID device into the stack, but without increasing the thickness of the stack. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  illustrates a prior-art system of labels, wherein an RFID inlay is held between the labels  3  and a liner  6 .  
         [0010]      FIG. 2  is a cross-sectional view of one label in  FIG. 1 .  
         [0011]      FIG. 3  is a simplified schematic of a process in which the labels of  FIG. 1  are manufactured.  
         [0012]      FIGS. 4, 5 , and  8  illustrate a sequence of processing events undertaken in one form of the invention.  
         [0013]      FIG. 6  is a perspective view of part of  FIG. 5 .  
         [0014]      FIG. 7  is a cross-sectional view of  FIG. 6 .  
         [0015]      FIGS. 9, 11 ,  12 , and  13  illustrate different combinations of components utilized by several forms of the invention.  
         [0016]      FIG. 10  illustrates adhesive layer  24 .  
         [0017]      FIGS. 14 and 15  illustrate sequences of processing steps used in fabricating the invention.  
         [0018]      FIG. 16  illustrates a connecting lead  77  between the RFID device  12  and the antenna  15 .  
         [0019]      FIGS. 17 and 18  illustrate alternate configurations of the connecting lead  77 .  
         [0020]      FIG. 19  illustrates a sequence of processing steps undertaken by one form of the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIG. 4  illustrates a liner  6 , in which through-perforations  21  are punched.  FIG. 5  illustrates RFID devices  12  placed into the perforations  21 , and the antennas  15  which flank the RFID device  12 .  FIG. 6  illustrates the situation in perspective view, without the antennas, and  FIG. 7  illustrates the situation in cross-sectional view.  
         [0022]     In  FIG. 8 , labels  3  are attached to the liner  6 . As shown in  FIG. 10 , a layer of adhesive  24  is present, which performs three functions. One, it removably attaches the label  3  to the liner. Two, it attaches the RFID device to the label, Three, it attaches the antennas  15  in  FIG. 8  to the label  3 .  
         [0023]     Under this arrangement, when the label  3  is peeled from the liner, both the antennas  15  and the RFID device  12  come along with the label, but for two different reasons. As to the RFID device  12 , it follows the label  3  because it was not in contact with the liner, let alone adhered to the liner  6 . As to the antenna  15 , it follows the label  3  because, although it was in contact with the liner  6 , there is no adhesive between the antennas  15  and the liner  6 . The adhesive is between the antennas  15  and the label, adhering them together, and not adhering the antennas  15  to the liner  6 .  
         [0024]      FIGS. 9 and 11 - 13  illustrate several different arrangements of components, as used by the invention.  FIG. 9  illustrates the arrangement discussed above: the perforation  21  is within in the liner  6 , and the RFID device  12  resides in the perforation.  
         [0025]     In  FIG. 11 , the perforation  21  is formed in the label  3 , rather than in the liner  6  as above. The antennas can be located between the label  3  and the liner  6 . A patch  27  in  FIG. 12  can be added, which can take the form of a self-adhesive label, which affixes the RFID device  12  to the label  3 , and holds the RFID device  12  in place when the label  3  is removed from the liner  6 .  
         [0026]      FIG. 13  illustrates a situation where no perforation is used, but depressions  30  are formed in both the label  3  and the liner  6 , which together form a cavity which contains the RFID device  12 . Adhesive  36  attaches the RFID device  12  to the label  3 . A similar adhesive (not shown) attaches the antennas (not shown) to the label  3 .  
         [0027]     In another embodiment, the antennas are installed at a different time than is the RFID device. One justification for the different installation times is that many antennas are sturdier than are the RFID devices. For example, if the antenna takes the form of a strip of foil, the strip can be in the approximate range of 0.001 to 0.005 inches thick. If such a strip is laminated between two layers of paper, the thickness is not increased appreciably, and the overall structure can withstand significant pressure and abuse.  
         [0028]     In contrast, if the RFID device is 0.1 inch thick, the situation becomes like that of  FIG. 2 , wherein resistance to pressure is not so great. One reason is that, if a roller is applying pressure, the pressure is distributed across the width of the liner, that is, across width W in  FIG. 4 . However, when the roller reaches the RFID device of  FIG. 2 , the entire force of the roller is concentrated over smaller width W 2  in  FIG. 5 . The pressure, in units of force per unit width, becomes much larger.  
         [0029]     Since, under this reasoning, the antenna may be more robust than the RFID device, the antenna is installed prior to the RFID device. For example, in  FIG. 14 , the antenna is installed at point  50 . Processing  53  is then undertaken, and then the RFID device, or chip, is installed at point  56 .  
         [0030]     In the more general case, in  FIG. 15 , processing  60  occurs, then the antenna is installed at point  63 . Other processing  65  follows, followed by installation of the RFID device, at point  68 . Then further processing  70  may occur.  
       Additional Considerations  
       [0031]     1. The Inventors point out that, it is preferable that the RFID device be the same thickness as the sheet which surrounds it. For example, in  FIG. 6 , it is preferable that both the RFID device  12  and the liner  6  be of the same thickness T 2 .  
         [0032]     However, the RFID device and the liner, or label, may not be the same thickness.  FIG. 16  illustrates one situation. The top of the Figure is a perspective view. The central part of the Figure is a cross-sectional view, and shows that the RFID device  12  is thinner than the sheet  75  surrounding it. Consequently, the conductive lead  77  which connects to the antenna  15  must bridge the difference D in height, as the magnified insert in the Figure shows.  
         [0033]     Similarly, if the RFID device is thicker than the sheet surrounding it, a conductive lead  82  in  FIG. 17  must drop down to the level of the antenna.  
         [0034]     In theory, the conductive lead between the antenna and the RFID chip can feed directly to the RFID chip, as in  FIG. 18 . However, in practice, such a feed is undesirable, because it increases cost. That is, the RFID chip will certainly be manufactured as an integrated circuit, probably on a silicon wafer. Since such circuits are fabricated layer-by-layer, it is more convenient to place signal contact pads within a layer, rather than at the edge of a layer. Edge-type positioning would be required in the case of  FIG. 18 .  
         [0035]     2.  FIG. 19  illustrates one sequence of assembly, wherein the antenna is installed prior to the RFID device. The sequence begins with backing liner  6 . An antenna  15  is positioned on the liner  6 , as indicated. Contact pads  80  are shown exaggerated in size, for emphasis.  
         [0036]     RFID device  12  is then installed. Blocks  81  represent masses of a solder-like substance, used to make electrical contact between contact pads  84 , on the RFID device  12 , and the pads  80 , on the antenna  15 . A conductive adhesive, such as an epoxy filled with silver powder, can be used.  
         [0037]     Then label  3 , bearing perforation  21 , is installed, as shown at the end of the sequence.  
         [0038]     3. In one form of the invention, the labels under consideration are of the sheet-type, having a thickness in the range of 0.002-0.015 inches. This is to distinguish over articles such as hood ornaments and three-dimensional advertising signs, which could be considered labels, but are not manufactured using the processes which produce peel-off labels attached to a backing web, as described herein.  
         [0039]     4. The labels under consideration can contain graphic images as well as textual information.  
         [0040]     5. If the antenna is installed first, and the RFID device installed later, it is possible that no need exists for the perforations  21  shown in  FIG. 4 . That is, if the RFID device is installed after the potentially abusive processing steps, then the need for protecting the RFID device may disappear.  
         [0041]     Accordingly, in one form of the invention, the antenna is installed first, then the potentially abusive processing is undertaken, followed by installation of the RFID device. In this form of the invention, the RFID device is laminated between the label and the liner, producing a structure as shown in  FIG. 2 .  
         [0042]     Numerous substitutions and modifications can be undertaken without departing from the true spirit and scope of the invention. What is desired to be secured by Letters Patent is the invention as defined in the following claims.