FI111485B - A method of affixing an RFID tag to one surface - Google Patents

Description

111485

A method of affixing an RFID tag to one surface

The present invention relates to a method of affixing an RFID tag having a wire pattern and a microchip chip to one surface, and an RFID tag having a wire pattern and a microchip chip.

The prior art methods have certain drawbacks. Production lines are complex and rarely suitable for the production of small labels. Their investment costs are quite high and material losses occur during production. The heat sealing properties of the materials may be poor, or the choice of materials may be limited. The electronic performance of the RFID tag will decrease over time.

The present invention provides an improvement on the prior art. The method of the invention is characterized in that the RFID tag is affixed to one surface by a thermoplastic adhesive film. The RFID tag according to the invention is characterized in that the outer surface of the RFID tag comprises a thermoplastic adhesive film.

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With the use of a thermoplastic adhesive film, the application of an RFID tag is quick and easy and can be repeated due to the properties of the thermoplastic adhesive films. Other materials can be selected for the RFID tag from a wide range of materials, since, for example, the poor heat sealing properties of other materials do not need to be addressed due to the heat sealing properties of the thermoplastic adhesive films. The RFID tag with thermoplastic film has a durable electrical performance. The thermoplastic adhesive film protects the conductor pattern and / or the microchip chip from environmental conditions. The loss coefficient of film 30 is low. In some embodiments of the invention, the attachment of the chip and the affixing of the tag to one surface can be made with the same thermoplastic adhesive film. Other advantages of the invention are: - process steps can be reduced, 35 - production lines are reliable, - investment costs are low for large production volumes, - material costs are minimized, 2 111485 - process steps can be designed for small labels, and - the customer needs better.

5 Thermoplastic adhesive films are films whose surface can be adhesively adhesive to one surface but which are substantially non-adhesive at room temperature. The thermoplastic adhesive films can also be heated several times without substantially affecting adhesion. An example of thermoplastic adhesive films is 10 3M anisotropically conductive films 8773 and 8783 (Z-Axis Adhesive Films 8773 and 8783). The membranes contain conductive particles such that they are conductive only in the film thickness direction; in other words, the conductivity is not in the direction of the film plane. The thermoplastic adhesive film can be made fluid by heat and pressure.

15 The thermoplastic adhesive film contains crystalline and amorphous regions which enable its performance. Upon cooling, the thermoplastic adhesive film will solidify and give the bond mechanical strength. No heat curing is required. The thermoplastic adhesive film can be made, for example, of polyester, polyetheramide or polyolefin. The conductive particles having a size 20 typically of 7-50 µm may be e.g. The thickness of the thermoplastic adhesive film is typically 20 to 70 µm. The thermoplastic adhesive film is generally formed on the surface of a release paper or the like. The release paper may be detached from the film 25 during or after heating the film. In addition to the anisotropically conductive films, the thermoplastic adhesive films may be non-conductive films. The thermoplastic adhesive film is attached to the RFID flag web so that it is in contact with the wire patterns.

30 In order to distinguish the aforementioned thermoplastic adhesive films from other thermoplastic adhesive films, the present application uses other thermoplastic films as conventional thermoplastic films.

In the present application, RFID tags refer to labels comprising an RF-ID circuit (tag). RFID tags are usually labels that operate in UHF or microwave bands, or labels that do not operate at frequencies above 13.56 MHz and often have a width of up to 3,114,585 20mm and a length of up to 100mm. They are suitable for use on smart stickers, smart cards, cardboard, paper or plastic admission tickets, disposable syringes for molding and smart bracelets, for example in amusement parks.

The RF-ID circuit comprises a conductor pattern and a microchip chip. The RFID tag can be produced by printing a wire pattern on the film with electrically conductive ink, etching the wire pattern on a metal film, stamping a wire pattern on a metal film, or twisting a wire pattern on, for example, a copper 10 wire. An electrically operated RF-ID (Radio Frequency Identification Circuit) on an RFID tag is a simple electrical vibration circuit (RCL) operating at a specific frequency. The circuit consists of a coil, a capacitor and an integrated circuit chip. The integrated circuit comprises a satellite memory and a radio frequency section arranged to communicate with the reader device.

The RCL circuit capacitor may also be integrated in the chip.

The RFID tags are preferably manufactured in the form of a web. In a first step, the web typically consists of a set of consecutive and adjacent RFID tags. Wire patterns are formed on the tags.

The RFID flag web is a material that is flexible but still stiff, such as polycarbonate, polyolefin, polyester, polyethylene terephthalate (PET), polyvinyl chloride (PVC) or copolymer of alkylonitrile, butadiene and styrene (ABS). The material is preferably polyester or polypropylene.

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After forming the wire patterns, there are several options to continue the process of making RFID tags. Some process alternatives will be further described in the detailed description of the preferred embodiments. There are basically three ways to continue the process.

According to the first and second alternatives, the web is cut narrower and fed into a flip-chip die so / te /.

This tool is generally a device configured to take a chip from a semiconductor wafer and attach it to a wiring pattern on a label, but other functions such as the lamination process can be incorporated into the same process line.

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In the first alternative, the web is laminated in the tool with either an anisotropically conductive thermoplastic film or a non-conductive thermoplastic film. After laminating, the chip is attached to a thermoplastic adhesive film. The final attachment of the chip is done by heat and pressure.

The web may be rolled immediately, or may be laminated with a pressure-sensitive binder or thermoplastic binder and stamped to form a laminated web comprising release paper. The latter binder is affixed to the other side of the RFID tag web as a thermoplastic adhesive film. The web is fed to a dispenser or laminator 10.

Another alternative is to apply an anisotropically conductive polymer or film on the conductor pattern to attach the chip to the conductor pattern. The polymer or film may also be on the surface of the chip. The material used for attaching the chip may be either thermoplastic or thermosetting plastic. It may also be a conductive binder or solder paste. After the chip is pre-mounted, heat and pressure are applied to secure the final chip. The web is then laminated with an anisotropically conductive thermoplastic film or non-conductive thermoplastic film or conventional thermoplastic film to cover conductor patterns and chips. The web can be rolled immediately, or it may be laminated with a pressure-sensitive binder or thermoplastic binder and stamped to form a laminated web comprising a release paper. The latter binder is affixed to the other side of the RFID tag web as a thermoplastic adhesive film. The web is fed to a dispenser or laminator.

A third option is to first laminate on the back side of the web a binder on release liner, which may be a pressure-sensitive adhesive or a thermoplastic binder. The laminated web is then stamped. The individual labels comprising the wire patterns are formed on a release paper web. Before attaching the chip, the conductor pattern is coated with an anisotropically conductive polymer or an anisotropically conductive film. The final attachment of the chip is done by heat and pressure. The web is then laminated with an anisotropically conductive thermoplastic film or a non-conductive thermoplastic film or a conventional thermoplastic film, or is rolled immediately after forming the final bond. The web is fed to a dispenser or laminator. The use of release paper requires that the chip be fastened either relatively quickly or at relatively low temperatures to prevent damage to the release liner.

5 In those embodiments where the chip is affixed to a thermoplastic adhesive film, the affixing is done by heating the label to the reverse side and lightly adhering to the label. The final bond between the conductor pattern and the chip is formed by heat and pressure using, for example, resistor elements that can be pressed against the chip to properly secure it. Final attachment is also necessary when other adhesives are used.

When the thermoplastic adhesive film is between the conductor pattern and the chip, an appropriate electrical contact is obtained even though a non-conductive thermoplastic adhesive film is used. In this case, however, the reliability of the contact is somewhat lower. The thermoplastic adhesive foils between the wire patterns and the chips replace the conventional fillings.

When the thermoplastic film is over the conductor pattern and the chip, conventional thermoplastic films can also be used, although the use of thermoplastic adhesive films is more advantageous due to their special properties.

In the dispenser or laminator, the RFID tag is affixed by a thermoplastic adhesive film to another surface, which may be pre-25, for example, carton, corrugated, plastic film, or paper.

The surface to which the label is affixed may be a finished product, for example a cardboard box, or the label may be affixed so that it is sandwiched between two layers of material in the final product. Distribution is easier when the individual successive labels are on a release paper web. This layer 30 is on the reverse side of the web relative to the thermoplastic adhesive film covering the conductor patterns.

The adhesive label is applied by first softening the thermoplastic adhesive film so that it adheres to the other surface. The web is softened by heating it with electrical resistors, infrared radiation or hot air blasting. Microwaves may be used for heating if a suitable additive is doped with the thermoplastic adhesive film. After this 6111485 the sticker is placed in the correct position. The correct placement is selected using appropriate sensor elements such as alignment marks or holes. Before affixing the tags, they are cut off from the web unless this has been done beforehand. Further treatment may be carried out to ensure that the sticker is firmly attached. This treatment may be performed, for example, in a nipple formed between two mating surfaces, at least one of which is soft, or in several successive nipples. The nip between the two counter surfaces may be formed, for example, between two rolls or between two belts, which may be supported by suitable means.

At least one contact surface may be heated, or additional heat may be introduced into the process, for example by means of a hot air fan or an infrared resistor. Special care must be taken in the lamination process when handling the chip. For example, the nip may be padded or grooved, at least at the chip, to prevent damage to the chip.

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In the drawings, Fig. 1 shows a top view of an RFID tag web W2, Fig. 2 shows a cross-section of an RFID tag, and Figures 3a-3f show some process alternatives.

FIG. Is a top view of an RFID flag web 1 having a single RFID-25 flag 12 comprising a conductor pattern 13 and a microchip chip 14. The conductor pattern is preferably made by etching it on a metal film, but other possibilities are to produce a conductor pattern on the film by electrically printing ink. or by twisting it, for example, on a copper wire. The wire pattern is equipped with an identification circuit 30, such as a radio frequency identification (RFID) circuit. The detection circuit is ·. "a simple electrical oscillation circuit (RCL circuit) tuned to operate at a specific frequency. The circuit consists of a coil, a capacitor, and a microcircuit chip consisting of a memory and a radio frequency portion capable of communicating with a reader device. .

111485 7

Figure 2 is a cross-sectional view of an RFID tag. For the sake of clarity, the various layers are shown as separate, although in reality they are closely laminated together.

The RFID tag comprises a conductor pattern 13 and an integrated circuit chip 14. The conductor pattern is formed on a web 1, preferably made of polyester or polypropylene.

In this embodiment, a thermoplastic adhesive film 10 2 is affixed to the web 1 after the chip 14 is attached. At a later stage of the process, the label is affixed to the other surface by means of a thermoplastic adhesive film. The other surface may be, for example, a suitable packaging material.

Figures 3a-3f are flow diagrams showing some alternatives for forming a process line 15. In the first step, the wire patterns are formed by a technique suitable for the web, such that the web has both adjacent and sequential wire patterns. In the processes of Figures 3a-3d, the wide web is cut narrower so that the web preferably comprises only successive wire patterns, i.e. the web is similar to a continuous strip. In the processes of Figures 3e-3f, the wide web comprising sequential and adjacent conductor patterns is first laminated with a binder, which may be, for example, a pressure sensitive binder (PSA) or a thermoplastic binder. Suitable binders include, for example, hot melt adhesives. The binder is usually on release liner.

25 The web of wire patterns is then punched to obtain

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individual stickers on release paper.

In the embodiments of Figures 3a and 3b, the web is laminated with an anisotropically conductive thermoplastic film or non-conductive thermoplastic film prior to attachment of a conductor patterned chip. In the embodiments of Figures 3c and 3d, there is a process step in which the web is coated with an anisotropically conductive polymer or an anisotropically conductive film which forms a chip fill. After the chip is adhered, a final attachment is made using heat and pressure.

In the embodiments of Figures 3a and 3f, the final process step is web winding and feeding to a dispenser or laminator, while in the embodiments of Figures 3c, 3d and 3e, the web is laminated with a thermoplastic adhesive film or a conventional thermoplastic film. The above step is the last step prior to winding and feeding the web to the dispenser or laminator in the embodiments of Figures 3d and 3e. In the process of Figure 3c, the web is laminated with a pressure-sensitive binder or thermoplastic binder and stamped as described above in connection with Figures 3e and 3f, and then rolled and fed to a dispenser or laminator. In the process of Figure 3b, after final bonding, the web is laminated with a pressure-sensitive binder or thermoplastic binder and punched and fed to a dispenser or laminator.

The invention is not limited to the above description, but the invention 15 may vary within the scope of the claims. The main idea of the invention is that when a thermoplastic adhesive film is attached to the surface of an RFID tag, the tag can be easily and cost-effectively affixed to the other surface.

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Claims (7)

111485 <1. A method of affixing an RFID tag comprising a conductor pattern (13) and a microchip chip (14) to one surface, characterized in that the RFID tag is affixed to the other surface by a thermoplastic adhesive film (2). Method according to Claim 1, characterized in that the thermoplastic adhesive film (2) is non-adhesive at room temperature. Method according to claim 1 or 2, characterized in that the thermoplastic adhesive film (2) is an anisotropically conductive film. Method according to one of the preceding claims, characterized in that the thermoplastic adhesive film (2) is a non-conductive film. 15 Method according to one of the preceding claims, characterized in that the RFID tag is affixed to the packaging material. An RFID tag comprising a conductor pattern (13) and an integrated circuit chip (14), characterized in that the outer surface of the RFID tag comprises a thermoplastic adhesive film (2). 7. A label according to claim 6, characterized in that the thermoplastic adhesive film (2) is intended for affixing the label to one surface. • '* »• · 111485