Transponder and injection-molded part and method for manufacturing same

• US 6,687,131 B1
• Filed: 02/24/2000
• Issued: 02/03/2004
• Est. Priority Date: 05/14/1999
• Status: Expired due to Fees

• Current Assignee: Sokymat
• Original Assignee: Sokymat
• Inventors: Miehling, Martin
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): DINH, TUAN T
• Application Number:
  US09/512,223
• Time in Patent Office: 1,440 Days
• Field of Search: 361/736, 361/737, 361/748-751, 361/760-765, 174/52.1, 340/572.2, 340/572.7, 340/572.8, 340/447, 343/895, 343/702, 152/152.1
• US Class Current: 361/760
• CPC Class Codes: B29C 2045/14131 using positioning or centering means forming part of the insert
• CPC Class Codes: B29C 2045/14852 incorporating articles with a data carrier, e.g. chips memory cards, chip cards B29L2017/006
• CPC Class Codes: B29C 39/10 incorporating preformed parts or layers, e.g. casting around inserts or for coating articles coating a surface by casting in general B05D1/30, B29C39/126 takes precedence
• CPC Class Codes: B29C 39/123 Making multilayered articles
• CPC Class Codes: B29C 45/14073 using means being retractable during injection
• CPC Class Codes: B29C 45/14639 for obtaining an insulating effect, e.g. for electrical components
• CPC Class Codes: B29C 45/1671 with an insert
• CPC Class Codes: B29K 2105/0097 Glues or adhesives, e.g. hot melts or thermofusible adhesives
• CPC Class Codes: G06K 19/04 characterised by the shape
• CPC Class Codes: G06K 19/047 the record carrier being shaped as a coin or a gambling token
• CPC Class Codes: G06K 19/07724 the record carrier being at least partially made by a molding process molding in general B29C45/14
• CPC Class Codes: G06K 19/07745 Mounting details of integrated circuit chips
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07781 the coil being fabricated in a winding process
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/0102 : Calcium [Ca]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

A transponder contains an integrated circuit, a power transmitting component (antenna) and a capsule made of a thermoplastic resin (hot glue) that surrounds the circuit continuously at least on one surface of the circuit. The glue preferably is a polyamide and surrounds the circuit protectively, ensuring a mechanical connection between the circuit and the antenna. The encapsulation with the hot glue is conducted at pressures and temperatures that are below the pressures and temperatures encountered during conventional injection molding. The transponder can be integrated into an injection molded part, for example a coin, by being placed in an injection mold in which it is supported by feet and then surrounded by molding material in a conventional injection molding process so that it develops a more resistant sheath.

Claims

1. An electrical circuit comprised in integrated circuit, an antenna and one or more electrical connections between the integrated circuit and the antenna, wherein at least the integrated circuit and the antenna are encapsulated within a capsule such that the capsule mechanically connects the integrated circuit and the antenna to hold the integrated circuit and the antenna in a fixed position relative to each other, and wherein the capsule comprises a polyamide thermoplastic resin having a melting point of from 120°

C. to 250°

C. and a processing pressure of from 5 to 40 bar.

2. The electrical circuit according to claim 1, wherein the capsule completely encapsulates the electrical circuit.

3. The electrical circuit according to claim 1, wherein the capsule encapsulates the electrical circuit only on one surface of the electrical circuit.

4. The electrical circuit according to claim 1, wherein the electrical circuit is encapsulated within the capsule such that at least one or more electrical connections are encapsulated by the thermoplastic resin.

5. The electrical circuit according to claim 1, wherein the antenna is a coil.

6. The electrical circuit according to claim 1, wherein the polyamide resin of the capsule contacts the integrated circuit and the antenna.

8. Transponder comprising an electrical circuit containing at least one component suitable for interaction with an electromagnetic field encapsulated within a capsule, wherein the capsule comprises a polyamide thermoplastic resin having a melting point of from 120°

C. to 250°

C. and a processing pressure of from 5 to 40 bar, and wherein the electrical circuit is encapsulated by the polyamide thermoplastic resin such that at least an integrated circuit and an antenna of the electrical circuit are encapsulated by the polyamide thermoplastic resin and are mechanically connected by the polyamide thermoplastic resin to hold the integrated circuit and the antenna in a fixed position relative to each other.

7. Transponder according to claim 8, wherein the polyamide resin of the capsule contacts the integrated circuit and the antenna.

9. Transponder according to claim 8, wherein at least part of a surface of the capsule is covered with a cover layer of laminated film.

10. Transponder according to claim 8, wherein the antenna is a coil.

11. Transponder according to claim 8, wherein the electrical circuit further comprises one or more electrical connections connecting the integrated circuit in electrically conducting fashion with the antenna.

12. Transponder according to claim 8, wherein the capsule further comprises at least one supporting element projecting from a surface of the capsile.

13. Transponder according to claim 8, wherein the capsule includes a material used as a mold during encapsulation with the thermoplastic resin.

14. Transponder according to claim 8, wherein the transponder further comprises a sheath of injection molded resin surrounding the encapsulated electrical circuit.

15. Transponder according to claim 9, wherein the laminated film comprises a plastic.

16. Transponder according to claim 15, wherein the plastic is polyvinyl chloride.