Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
1998-12-30
2001-10-30
Frech, Karl D. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S492000, C439S630000
Reexamination Certificate
active
06308889
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to smart card readers, and more particularly, but not by way of limitation, to a card reader for eliminating problems with electrostatic discharge that often occurs when a smart card is inserted into a card reader.
HISTORY OF THE PRIOR ART
Credit cards have long been an accepted part of life around the world. Early credit cards had identifying information raised from the remainder of the card, and the identifying information was transferred from the card by the use of pressure and carbon paper. More modern credit and debit cards have their identifying information as fixed electronic data, such as a scanable magnetic strip embedded on the surface of a card. Such identifying information exists within the card in a read-only format. Smart cards, the most recent advancement in the card art, utilize an active integrated circuit embedded within the card to store identifying information. Unlike prior art cards, smart cards have the additional capability of altering the identifying information stored in their integrated circuits. Smart cards may be utilized for any function of a prior art credit or debit card and have also proven useful in a wide variety of other functions, including paying bills; paying for mass transit; performing health care benefit transactions; and in using pay telephones, automated teller machines, in-home digital satellite systems, “set top” boxes used with cable television, or other similar equipment.
The integrated circuit in a smart card is typically a memory chip or a microprocessor chip. To provide access to the information stored in the integrated circuit of the card, operative regions such as contact pads are provided on the surface of the card, and the integrated circuit is electrically connected to these operative regions.
A smart card reader typically has a housing having a slot through which the card is inserted and removed. After insertion, the smart card is manipulated into a reading position, in which the operative regions of the card are in contact with certain terminals in the card reader. The terminals of the card reader are typically electrically connected to a printed circuit board containing the additional circuity necessary for a given transaction. After a transaction is complete, the card is returned to the user.
Electrostatic discharge (ESD) frequently creates problems for smart card users. Smart cards are typically made of a nonconductive material, such as plastic. Normal handling of a card, such as removal and insertion of a card from a user's wallet or billfold, may cause electrostatic charge to build up in the card. When a user inserts a card into a smart card reader, and when the card comes into contact with the conductive terminals of the card reader, electric shock may occur. This electric shock is similar to the shock that occurs when one walks across a carpeted floor and then touches a metal object such as a lamp. Such shock may damage or cause malfunction of the integrated circuit within the smart card, and it may also damage or cause malfunction of the circuitry on the printed circuit board to which the card reader is electrically connected.
In addition, after a period of use, body oils or other partially conductive material may collect on the surface of a smart card. Such conductive material may be sufficient to transfer electrostatic charge built up on the user of a card to the card itself. Such additional electrostatic charge exacerbates the ESD problems experienced by smart cards.
Several prior art techniques have been formulated to address the ESD problem of smart cards. For example, it is known to provide a smart card reader with a cover or top portion made of a conductive material and to connect the cover to ground. During insertion, a smart card contacts the cover before it contacts the conductive terminals connected to the base or bottom portion of the smart card reader. In this way, electrostatic charge may be discharged through the cover to ground, and a damaging electric shock is avoided. U.S. Pat. No. 5,380,997 assigned to Alcatel Radiotelephone discloses such a technique.
In addition, it is known to form a card reader cover from a highly resistive, yet conductive material and to ground the cover to a chassis. Alternatively, it is also known to paint or coat the cover of a card reader with a highly resistive, yet conductive material and to ground the painted cover to a chassis. Such materials provide a relatively slow discharge rate for the electrostatic charge, in contrast to the relatively fast discharge rate of a damaging electric shock. Furthermore, a variety of conventional conductive plastics providing ESD protection and electromagnetic interference shielding are sold by the Bekaert Corporation of Marietta, Ga. under the BEKI-SHIELD trademark.
With the availability of such conventional techniques to address the ESD problems of a smart card reader, it would be advantageous to provide a simple, low cost technique of grounding a conductive card reader cover. The smart card reader of the present invention provides several advantageous grounding techniques and several techniques to insure proper electrical isolation of the electrical components of the card reader without a substantial increase in complexity or cost as compared to conventional card readers.
SUMMARY OF THE INVENTION
The present invention pertains to grounding techniques for a smart card reader and techniques to insure proper electrical isolation of the electrical components of the smart card reader. More particularly, one aspect of the invention includes an improved smart card reader of the type having a non-conductive base and a conductive, grounded cover mated with the base to form a slot for insertion of a smart card. The base has a least one terminal for contacting an operative region of the smart card and a switch electrically connected to a base ground pin. The base ground pin is for electrically connecting to a ground of a printed circuit board. The improvement of the present invention comprises a cover ground pin electrically connected to the base ground pin and upwardly depending from the base. An aperture is provided in the cover that receives at least a portion of the cover ground pin and makes electrical connection therewith.
In another aspect, the present invention includes a smart card reader of the type having a non-conductive base and a conductive, grounded cover mated with the base to form a slot for insertion of a smart card. The base has a plurality of terminals for contacting an operative region of the smart card. The improvement comprises a plurality of slots formed in the cover, in which each of the plurality of slots is disposed directly above one of the plurality of terminals. Such a cover insures proper electrical isolation of the terminals of the smart card reader.
In a further aspect, the invention includes an improved smart card reader of the type having a non-conductive base and a conductive, grounded cover mated with the base to form a slot for insertion of a smart card. The base has a least one terminal having a first end for electrically connecting to a printed circuit board and a second end for contacting an operative region of smart card. The improvement comprises a conductive post downwardly depending from the cover and through a grounded hole in the printed circuit board. The post makes electrical connection with the grounded hole.
In a further aspect, the invention includes an improved method for grounding a conductive cover of a smart card reader. The card reader has a non-conductive base mated with the cover, and the base has a switch electrically connected to a base ground pin. The base ground pin is for electrically connecting to a ground of a printed circuit board. The improvement comprises electrically connecting a cover ground pin to said base ground pin, and positioning the cover ground pin in the base so that the cover ground pin is in physical and electrical contact with the cover.
In a further aspect, the invention includes an improved method
Cuff Michael Patrick
Folta Claude Grant
Grant John Lincoln
Airborn, Inc.
Frech Karl D.
Jenkens & Gilchrist a Professional Corporation
Lee Diane I.
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