Pressure activated fingerprint input apparatus

• US 20050213799A1
• Filed: 05/24/2005
• Published: 09/29/2005
• Est. Priority Date: 12/19/2002
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Sawano, Tomomi
• Granted Patent: US 7,760,921 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

An image input apparatus includes an image reading assembly positioned below a placement surface on which an object to be examined is placed, and a sensing circuit for sensing that the object is placed on the placement surface, in accordance with a pressure applied to the placement surface.

Claims

1. An image input apparatus comprising:

an image reading assembly having, on one side, a placement surface on which an object to be examined is placed; and

sensing means for sensing that the object is placed on the placement surface, in accordance with a pressure applied to the placement surface by the object.

2. An image input apparatus according to claim 1, which further comprises driving means for causing the image reading assembly to perform an image reading operation, when the sensing means senses that the object is placed on the placement surface.

3. An image input apparatus according to claim 1, wherein the sensing means comprises:

a pressure sensor which senses a pressure applied to the placement surface; and

comparing means for comparing a pressure level sensed by the pressure sensor with a threshold value for discriminating between a placed state and unplaced state and, if the threshold value is reached, outputting a trigger signal for causing the image reading assembly to perform an image reading operation.

4. An image input apparatus according to claim 3, which further comprises a light source which illuminates the object with light on the basis of the trigger signal.

5. An image input apparatus according to claim 1, which further comprises adjusting means for adjusting brightness of the light source for irradiating the object with light, in accordance with a pressure applied to the placement surface by the object.

6. An image input apparatus according to claim 1, wherein the placement surface has first and second regions, the image reading assembly has the first region of the placement surface, and the sensing means is positioned in the second region of the placement surface.

7. An image input apparatus according to claim 6, wherein the first region is a region where a portion beyond a first joint of a finger is placed, and the second region is a region where a portion from a second joint to a first joint of a finger is placed.

8. An image input apparatus according to claim 1, wherein the image reading assembly has an optical sensor.

9. An image input apparatus according to claim 8, wherein the optical sensor has a plurality of double-gate transistors arranged in a matrix manner.

10. An image input apparatus according to claim 1, which further comprises a holder which holds the object such that the object is properly placed in. positions of the image reading assembly and sensing means.

11. An image input apparatus comprising:

an image reading assembly having, on one side, a placement surface on which an object to be examined is placed; and

sensing means placed on the other side of the image reading assembly to sense that the object is placed on the placement surface, in accordance with a pressure applied to the placement surface by the object.

12. An image input apparatus according to claim 11, which further comprises driving means for causing the image reading assembly to perform an image reading operation, when the sensing means senses that the object is placed on the placement surface.

13. An image input apparatus according to claim 11, wherein the sensing means comprises:

a pressure sensor which senses a pressure applied to the placement surface; and

comparing means for comparing a pressure level sensed by the pressure sensor with a threshold value for discriminating between a placed state and unplaced state and, if the threshold value is exceeded, outputting a trigger signal for causing the image reading assembly to perform an image reading operation.

14. An image input apparatus according to claim 11, which further comprises light irradiating means for irradiating the object with light, placed between the image reading assembly and sensing means.

15. An image input apparatus according to claim 14, wherein the light irradiating means has a diffusion light-guiding plate which guides, to the object, light from a light source which emits light when the object is sensed by the sensing means.

16. An image input apparatus according to claim 11, which further comprises adjusting means for adjusting brightness of light for irradiating the object with light, in accordance with a pressure applied to the placement surface by the object.

17. An image input apparatus according to claim 11, wherein the image reading assembly has an optical sensor.

18. An image input apparatus according to claim 17, wherein the optical sensor has a plurality of double-gate transistors arranged in a matrix manner.

19. An image input apparatus according to claim 11, which further comprises a holder which holds the object such that the object is properly placed in positions of the image reading assembly and sensing means.

20. An image input apparatus comprising:

sensing means for outputting a sense signal in accordance with a pressure of a finger when the finger is placed on the sensing means;

a plurality of sensor elements which are positioned below a fingerprint portion of the finger when the finger is placed on the sensing means, and read an image corresponding to projections and recesses of the finger; and

a driving circuit which starts an image reading operation of said plurality of sensor elements in accordance with the sense signal.