Fingerprint detection apparatus

• US 5,940,525 A
• Filed: 03/06/1997
• Issued: 08/17/1999
• Est. Priority Date: 03/08/1996
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Itsumi, Kazuhiro
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Mariam, Daniel G.
• Application Number:
  US08/811,718
• Time in Patent Office: 894 Days
• Field of Search: 382/115, 382/116, 382/124, 382/312, 283/68, 283/69
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

A fingerprint detection apparatus includes a plurality of first electrodes having linear shapes and arranged in parallel to one another, a plurality of second electrodes arranged between said plurality of first electrodes and arranged in the longitudinal direction of each of said plurality of first electrodes, keeping apart from one another, and detecting section for obtaining a fingerprint image in accordance with resistance value groups each of which is generated between the adjacent first and second electrodes when the finger of a person required to be identified has been brought into contact with said plurality of first and second electrodes. Therefore, the fingerprint of a person required to be identified can be detected without a complicated optical system.

Claims

1. A fingerprint detection apparatus for obtaining a two-dimensional image of a fingerprint, comprising:

a plurality of point electrodes arranged in rows and columns to form a matrix;

a plurality of parallel linear electrodes extending along a first direction corresponding to a direction of said rows or columns, wherein each linear electrode is positioned between pairs of first ones of said plurality of point electrodes forming one of said rows or columns and second ones of said plurality of point electrodes forming a next adjacent one of said rows or columns;

a plurality of connection lines extending in a direction different from said first direction, wherein each connection line commonly connects together a group of point electrodes including only one of said point electrodes of any one of the pairs so that the point electrodes of any pair on opposite sides of a given linear electrode are disconnected; and

means for determining resistance between any particular linear electrode and a point electrode adjacent thereto by applying a predetermined voltage between the particular linear electrode and one of said plurality of connection lines.

2. The apparatus according to claim 1, wherein said means for determining resistance includes,

a plurality of first switches, wherein each first switch is connected to a respective one of said plurality of linear electrodes and a first terminal of a voltage source supplying said predetermined voltage,

a plurality of second switches, wherein each second switch is connected to a respective one of said plurality of connection lines and a second terminal of said voltage source supplying said predetermined voltage, and

means for performing sequence control relative to said plurality of first and second switches such that said predetermined voltage between said each linear electrode and each one of said plurality of connection lines is applied sequentially to determine the resistance between each linear electrode and each point electrode adjacent thereto.

3. The apparatus according to claim 1, wherein said means for performing sequence control includes a plurality of counters and decoders.

4. The apparatus according to claim 1, wherein said means for determining resistance includes a reference power source for applying said predetermined voltage.

5. The apparatus according to claim 1, further comprising means for obtaining a fingerprint image based on plural resistance values being outputted from said means for determining resistance.

6. The apparatus according to claim 1, wherein said plurality of point electrodes and said plurality of linear electrodes are made of thin conductive films.

7. The apparatus according to claim 1, further comprising an insulating substrate on which said plurality of point electrodes and said plurality of linear electrodes are formed.

8. A fingerprint detection apparatus for obtaining a two-dimensional image of a fingerprint, comprising:

a plurality of point electrodes arranged in rows and columns to form a matrix;

a plurality of parallel linear electrodes extending along a first direction corresponding to a direction of said rows or columns, wherein each linear electrode is positioned between pairs of first ones of said plurality of point electrodes forming one of said rows or columns and second ones of said plurality of point electrodes forming a next adjacent one of said rows or columns;

a plurality of connection lines extending in a direction different from said first direction, wherein each connection line commonly connects together a group of point electrodes including only one of said point electrodes of any one of the pairs so that the point electrodes of any pair on opposite sides of a given linear electrode are disconnected, with each said group being located at intervals of at least one point electrode in said first direction; and

means for determining resistance between any particular linear electrode and a point electrode adjacent thereto by applying a predetermined voltage between the particular linear electrode and one of said plurality of connection lines.

9. The apparatus according to claim 8, wherein said means for determining resistance includes:

a plurality of first switches, wherein each first switch is connected to a respective one of said plurality of linear electrodes and a first terminal of a voltage source supplying said predetermined voltage,

a plurality of second switches, wherein each second switch is connected to a respective one of said plurality of connection lines and a second terminal of said voltage source supplying said predetermined voltage, and

means for performing sequence control relative to said plurality of first and second switches such that said predetermined voltage between said each linear electrode and each one of said plurality of connection lines is applied sequentially to determine the resistance between each linear electrode and each point electrode adjacent thereto.

10. The apparatus of according to claim 8, wherein said means for performing sequence control comprises a plurality of counters and decoders.

11. The apparatus according to claim 8, wherein said means for determining resistance includes a reference power source for applying said predetermined voltage.

12. The apparatus according to claim 11, wherein said means for determining resistance further includes a reference resistance having a predetermined value connected in series to said reference power source.

13. The apparatus according to claim 12, further comprising means for obtaining a fingerprint image based on plural resistance values being outputted from said means for determining resistance, said plural resistance values being determined in terms of a detected voltage drop and the relation thereof to a voltage drop across the reference resistance.

14. The apparatus according to claim 8, wherein said plurality of point electrodes and said plurality of linear electrodes are made of thin conductive films.

15. The apparatus according to claim 8, further comprising an insulating substrate on which said plurality of point electrodes and said plurality of linear electrodes are formed.