Capacitive fingerprint sensing apparatus and capacitive fingerprint sensing method

• US 10,043,048 B2
• Filed: 04/26/2016
• Issued: 08/07/2018
• Est. Priority Date: 04/27/2015
• Status: Active Grant

• Current Assignee: Raydium Semiconductor Corporation
• Original Assignee: Raydium Semiconductor Corporation
• Inventors: Chiang, Chang-Ching, Huang, Yu Kuo
• Primary Examiner(s): Thomas, Mia M
• Application Number:
  US15/138,394
• Publication Number:
  US 20160314333A1
• Time in Patent Office: 833 Days
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

The capacitive fingerprint sensing apparatus and capacitive fingerprint sensing method of the invention perform fingerprint sensing through self-capacitive sensing technology and mutual-capacitive sensing technology respectively and combine the self-capacitive fingerprint pattern and the mutual-capacitive fingerprint pattern into a synthesized fingerprint pattern. Therefore, the capacitive fingerprint sensing apparatus and capacitive fingerprint sensing method of the invention can effectively increase the capacity sensed by the unit sensing electrode without decreasing its high resolution. As a result, not only the noise interference can be reduced to increase the accuracy of fingerprint recognition, but also the number of signal traces can be also reduced to simplify the circuit structure and save the chip area.

Claims

1. A capacitive fingerprint sensing apparatus, comprising:

M sensing lines;

N scanning lines;

a plurality of sensing electrodes configured to form a (N*M) matrix having N rows of sensing electrodes and M columns of sensing electrodes, wherein the M columns of sensing electrodes are arranged along a first direction and coupled to the M sensing lines respectively and the N rows of sensing electrodes are arranged along a second direction and coupled to the N scanning lines respectively, M and N are positive integers;

a scanning driver, coupled to the plurality of sensing electrodes through the N scanning lines respectively, configured to scan the N rows of sensing electrodes through the N scanning lines respectively in a self-capacitive sensing mode and in a mutual-capacitive sensing mode;

a sensing driver coupled to the plurality of sensing electrodes through the M sensing lines respectively, configured to perform self-capacitive sensing on the M columns of sensing electrodes through the M sensing lines respectively in the self-capacitive sensing mode and to perform mutual-capacitive sensing between odd columns of sensing electrodes and even columns of sensing electrodes of the N rows of sensing electrodes through odd sensing lines and even sensing lines of the M sensing lines respectively in the mutual-capacitive sensing mode; and

processing module, coupled to the plurality of sensing electrodes, configured to obtain a first fingerprint pattern in the self-capacitive sensing mode, to obtain a second fingerprint pattern in the mutual-capacitive sensing mode and then to combine the first fingerprint pattern and the second fingerprint pattern into a synthesized fingerprint pattern;

wherein a resolution of the synthesized fingerprint pattern along at least one direction is larger than a resolution of the first fingerprint pattern and a resolution of the second fingerprint, pattern along the at least one direction, wherein the at least one direction comprises at least one of the first direction, the second direction, . . . , and a L-th direction, and L≥

3.

2. The capacitive fingerprint sensing apparatus of claim 1, wherein a resolution of the first fingerprint pattern along the first direction is smaller than a resolution of the first fingerprint pattern along the second direction and a resolution of the second fingerprint pattern along the first direction is smaller than a resolution of the second fingerprint pattern along the second direction.

3. The capacitive fingerprint sensing apparatus of claim 1, wherein a resolution of the first fingerprint pattern along the second direction is smaller than a resolution of the first fingerprint pattern along the first direction and a resolution of the second fingerprint pattern along the second direction is smaller than a resolution of the second fingerprint pattern along the first direction.

4. The capacitive fingerprint sensing apparatus of claim 1, wherein a resolution of the first fingerprint pattern along the second direction is equal to a resolution of the first fingerprint pattern along the first direction and a resolution of the second fingerprint pattern along the second direction is equal to a resolution of the second fingerprint pattern along the first direction.

5. The capacitive fingerprint sensing apparatus of claim 1, wherein a resolution of the synthesized fingerprint pattern along the first direction and a resolution of the synthesized fingerprint pattern along the second direction are both equal to a resolution of the first fingerprint pattern along the second direction and a resolution of the second fingerprint pattern along the second direction.

6. The capacitive fingerprint sensing apparatus of claim 1, wherein a resolution of the synthesized fingerprint pattern along the first direction and a resolution of the synthesized fingerprint pattern along the second direction are different.

7. The capacitive fingerprint sensing apparatus of claim 1, wherein the sensing driver selects the odd sensing lines of the M sensing lines as signal transmitters (TX) and selects the even sensing lines of the M sensing lines as signal receivers (RX) or the sensing driver selects the odd sensing lines of the M sensing lines as the signal receivers (RX) and selects the even sensing lines of the M sensing lines as the signal transmitters (TX).

8. The capacitive fingerprint sensing apparatus of claim 1, wherein a J-th sensing line of the M sensing lines is coupled to every electrodes of a J-th column of sensing electrodes of the M columns of sensing electrodes respectively, J is a positive integer and 1≤

J≤

M, and a K-th scanning line of the N scanning lines is coupled to every electrodes of a K-th row of sensing electrodes of the N rows of sensing electrodes respectively, K is a positive integer and 1≤

k≤

N.

9. The capacitive fingerprint sensing apparatus of claim 1, wherein the plurality of sensing electrodes has random geometric shapes.

10. A capacitive fingerprint sensing apparatus, comprising:

(M+1) sensing lines;

N pairs of scanning lines, each pair of scanning lines comprising a first scanning line and a second scanning line;

a plurality of sensing electrodes configured to form a (N*M) matrix having N rows of sensing electrodes and M columns of sensing electrodes, wherein the M columns of sensing electrodes are arranged along a first direction and coupled to the (M+1) sensing lines respectively in a Zig-Zag way and the N rows of sensing electrodes are arranged along a second direction and coupled to the N pairs of scanning lines respectively, M and N are positive integers; and

a scanning driver, coupled to the plurality of sensing electrodes through the N pairs of scanning lines, configured to scan the N rows of sensing electrodes through the N pairs of scanning lines respectively in a self-capacitive sensing mode and to scan odd rows of sensing electrodes or even rows of sensing electrodes of the N rows of sensing electrodes through N first scanning lines and N second scanning lines of the N pairs of scanning lines respectively in a mutual-capacitive sensing mode;

a sensing driver, coupled to the plurality of sensing electrodes through the (M+1) sensing lines, configured to perform self-capacitive sensing on the M columns of sensing electrodes through the (M+1) sensing lines respectively in the self-capacitive sensing mode and to perform mutual-capacitive sensing on the M columns of sensing electrodes or the N rows of sensing electrodes through the (M+1) sensing lines respectively in the mutual-capacitive sensing mode;

a processing module, coupled to the plurality of sensing electrodes, configured to obtain a first fingerprint pattern, to obtain a second fingerprint pattern and then to combine the first fingerprint pattern and the second fingerprint pattern into a synthesized fingerprint pattern.

11. The capacitive fingerprint sensing apparatus of claim 10, wherein a resolution of the synthesized fingerprint pattern along at least one direction is larger than a resolution of the first fingerprint pattern and a resolution of the second fingerprint pattern along the at least one direction;

the at least one direction comprises at least one of the first direction, the second direction, . . . and a L-th direction, and L≥

3.

12. The capacitive fingerprint sensing apparatus of claim 10, wherein a resolution of the synthesized fingerprint pattern along the first direction and a resolution of the synthesized fingerprint pattern along the second direction are different.

13. The capacitive fingerprint sensing apparatus of claim 10, wherein a resolution of the synthesized fingerprint pattern along the first direction is equal to a resolution of the synthesized fingerprint pattern along the second direction.

14. The capacitive fingerprint sensing apparatus of claim 10, wherein the scanning driver selects odd sensing lines of the (M+1) sensing lines as signal transmitters (TX) and selects even sensing lines of the (M+1) sensing lines as signal receivers (RX) or the scanning driver selects the odd sensing lines of the (M+1) sensing lines as the signal receivers (RX) and selects the even sensing lines of the (M+1) sensing lines as the signal transmitters (TX).

15. The capacitive fingerprint sensing apparatus of claim 10, wherein a J-th sensing line and a (J+1)-th sensing line of the (M+1) sensing lines are coupled to any two adjacent sensing electrodes of a J-th column of sensing electrodes of the M columns of sensing electrodes respectively, J is a positive integer and 1≤

J≤

M, and a first scanning line and a second scanning line of a K-th pair of scanning lines of the N pairs of scanning lines are coupled to any two adjacent sensing electrodes in a K-th column of sensing electrodes of the M columns of sensing electrodes respectively, K is a positive integer and 1≤

K≤

N.

16. The capacitive fingerprint sensing apparatus of claim 10, wherein the plurality of sensing electrodes has random geometric shapes.

17. A capacitive fingerprint sensing method applied to a capacitive fingerprint sensing apparatus, the capacitive fingerprint sensing apparatus comprising a scanning driver, a sensing driver, a processing module, a plurality of sensing lines, a plurality of scanning lines and a plurality of sensing electrodes, the plurality of sensing electrodes being configured to be arranged in a regular way, the scanning driver being coupled to the plurality of sensing electrodes through the plurality of scanning lines respectively, the sensing driver being coupled to the plurality of sensing electrodes through the plurality of sensing lines respectively, the processing module being coupled to the plurality of sensing electrodes, the capacitive fingerprint sensing method comprising:

in a self-capacitive sensing mode, the scanning driver configured to scan the plurality of sensing electrodes through the plurality of scanning lines respectively and the sensing driver configured to perform self-capacitive sensing on the plurality of sensing electrodes through the plurality of sensing lines respectively;

in a mutual-capacitive sensing mode, the scanning driver configured to scan the plurality of sensing electrodes through the plurality of scanning lines respectively and the sensing driver configured to perform mutual-capacitive sensing on at least one pair of adjacent sensing electrodes of the plurality of sensing electrodes through the plurality of sensing lines respectively; and

the processing module configured to obtain a first fingerprint pattern in the self-capacitive sensing mode, to obtain a second fingerprint pattern in the mutual-capacitive sensing mode and then to combine the first fingerprint pattern and the second fingerprint pattern into a synthesized fingerprint pattern, wherein a resolution of the synthesized fingerprint pattern along at least one direction is larger than a resolution of the first fingerprint pattern and a resolution of the second fingerprint pattern along the at least one direction.

18. The capacitive fingerprint sensing method of claim 17, wherein the at least one direction comprises at least one of the first direction, the second direction, . . . , and a L-th direction, and L≥

3.

19. The capacitive fingerprint sensing method of claim 18, wherein a resolution of the first fingerprint pattern along the first direction is smaller than a resolution of the first fingerprint pattern along the second direction and a resolution of the second fingerprint pattern along the first direction is smaller than a resolution of the second fingerprint pattern along the second direction.

20. The capacitive fingerprint sensing method of claim 18, wherein a resolution of the first fingerprint pattern along the second direction is smaller than a resolution of the first fingerprint pattern along the first direction and a resolution of the second fingerprint pattern along the second direction is smaller than a resolution of t e second fingerprint pattern along the first direction.

21. The capacitive fingerprint sensing method of claim 18, wherein a resolution of the synthesized fingerprint pattern along the first direction and a resolution of the synthesized fingerprint pattern along the second direction are both equal to a resolution of the first fingerprint pattern along the second direction and a resolution of the second fingerprint pattern along the second direction.

22. The capacitive fingerprint sensing method of claim 18, wherein a resolution of the synthesized fingerprint pattern along the first direction and a resolution of the synthesized fingerprint pattern along the second direction are different.

23. The capacitive fingerprint sensing method of claim 18, wherein the regular way that the plurality of sensing electrodes is arranged is a matrix arrangement or a triangle arrangement.

24. The capacitive fingerprint sensing method of claim 18, wherein the at least one pair of adjacent sensing electrodes are sensing electrodes adjacent to each other along the first direction, the second direction, . . . or the L-th direction.