Browse Prior Art Database

Passive Identification Card and Reader

IP.com Disclosure Number: IPCOM000077535D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Abbott, GF: AUTHOR

Abstract

Fig. 1 shows a capacitive "credit card" 1 and reader 2, having a recessed reading area 3 with positioning periphery 4 for maintaining card 1 in proper orientation over sensors, that are imbedded in the surface 3 which is of nonconducting material of a type chosen to resist chemical and physical attack.

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Passive Identification Card and Reader

Fig. 1 shows a capacitive "credit card" 1 and reader 2, having a recessed reading area 3 with positioning periphery 4 for maintaining card 1 in proper orientation over sensors, that are imbedded in the surface 3 which is of nonconducting material of a type chosen to resist chemical and physical attack.

Fig. 2 illustrates the construction for card 1 in cross section. It consists of five layers of materials with the first layer 5, which contacts surface 3 of the card reader 2, being made of a dielectric material such as plastic approximately 1 mill thick. Layer 6 is a copper foil 1 to 2 mills in thickness having punched apertures 7 at various locations thereon, to serve as coding indicia to be discussed. As illustrated, plastic 5 bulges into hole 7 in foil 6 to nearly fill it. Layer 8 is a plastic substrate approximately 10 mills in thickness, which provides a mechanical base and stiffener for the card. Layer 9 is another copper foil approximately 4 mills in thickness, which serves as a ground plane and shield from outside electrical disturbances. Layer 10 is another plastic layer which is 1 to 2 mills in thickness, which serves as an insulator and shield against contamination.

Fig. 3 illustrates a portion of foil 6 on layer 5 with punched hole locations 7, which might be used in a typical 2'' by 3'' plastic card 2. Not all hole 7 locations will be punched out in a typical card, but only a coded array thereof would be punched. In a typical card, approximately 40 sensing spots could be located as shown in Fig. 3. The presence or absence of a h...