TWI621985B - Capacitive fingerprint sensing apparatus - Google Patents

Abstract

A capacitive fingerprint sensing device includes a plurality of sensing electrodes, a sensing driver, and a processing module. In the first self-capacitance sensing mode, the sensing driver selects adjacent M sensing electrodes and combines them into a first sensing electrode group to perform the first self-capacitance sensing to obtain a first self-capacitance fingerprint sensing signal; In the second self-capacitance sensing mode, the sensing driver selects adjacent N sensing electrodes and combines them into a second sensing electrode group to perform the second self-capacitance sensing to obtain a second self-capacitance fingerprint sensing signal. M and N are positive integers greater than 1. The processing module generates first and second self-capacitance fingerprint images based on the first and second self-capacitance fingerprint sensing signals and synthesizes them into a third self-capacitance fingerprint image. The adjacent M sensing electrodes and the adjacent N sensing electrodes share at least one sensing electrode.

Description

Capacitive fingerprint sensing device

The present invention relates to fingerprint sensing, and more particularly, to a capacitive fingerprint sensing device capable of taking into account both good fingerprint sensing capability and high resolution requirements.

With the advancement of technology, capacitive fingerprint sensing technology can be widely applied to various electronic devices, especially portable electronic devices, such as smart phones, notebook computers, and tablet computers. Because the fingerprint sensing technology has high resolution requirements, under the IAFIS specification, the fingerprint sensing chip must have a resolution of at least 500dpi and its unit sensing area must be 50um * 50um.

Please refer to FIG. 1. A conventional Fingerprint Sensor Array is composed of a plurality of sensing electrodes SE. Assume that the X-direction spacing and the Y-direction spacing between the sensing electrodes SE are Dx and Dy, respectively. When the fingerprint sensing driver 12 separately drives each sensing electrode SE for self-capacitance fingerprint sensing, if the fingerprint ridge is pressed on the sensing electrode SE, the sensing electrode SE will sense a larger capacitance; if the fingerprint valley is pressed, On the sensing electrode SE, the sensing electrode SE will sense a smaller capacitance. In this way, the processing module 14 can obtain a resolution of 1 / Dx in the X direction and a resolution of 1 / Dy in the Y direction according to the capacitance detected by each sensing electrode SE. The self-capacitance fingerprint sensing image, wherein each unit pixel in the self-capacitance fingerprint sensing image will correspond to the sensing center of gravity position P of each sensing electrode SE, respectively. When Dx = Dy = 50μm, the self-capacitance fingerprint sensing image has a resolution of 508dpi, so it can comply with the IAFIS standard for resolution.

Although the traditional self-capacitance fingerprint sensing technology can meet the IAFIS standard for resolution, in order to avoid long-term use or friction, the flatness of the fingerprint sensor applied to portable electronic devices will deteriorate, resulting in fingerprint sensing effects. Poor, the fingerprint sensor is usually covered with a protective layer (such as sapphire glass). Because the protective layer usually has a certain thickness (such as 100 μm), in this case, if a fingerprint sensor array with a resolution of 500 dpi is used , The amount of change in capacitance it senses is low, which is easily disturbed by noise, which makes the difficulty of fingerprint identification significantly increased. If the size of the fingerprint sensor is increased, the capacitance value can be increased, but It also causes a reduction in resolution.

From the above, it can be known that the traditional self-capacitance fingerprint sensing technology currently used is still difficult to take into account both good fingerprint sensing capability and high resolution requirements, which needs to be overcome urgently.

In view of this, the present invention proposes a capacitive fingerprint sensing device to effectively solve the aforementioned problems encountered in the prior art.

A specific embodiment of the present invention is a capacitive fingerprint sensing device. In this embodiment, the capacitive fingerprint sensing device can be operated in a first self-capacitance sensing mode and a second self-capacitance sensing mode, respectively. Capacitive fingerprint sensor The device includes a plurality of sensing electrodes, a sensing driver and a processing module. The plurality of sensing electrodes are arranged in a regular manner. The sensing driver is coupled to the plurality of sensing electrodes. In the first self-capacitance sensing mode, the sensing driver selects M sensing electrodes adjacent to each other among the plurality of sensing electrodes to combine to form a first sensing electrode. Group to perform a first self-capacitance sensing to obtain a first self-capacitance fingerprint sensing signal; in the second self-capacitance sensing mode, the sensing driver selects N of the plurality of sensing electrodes adjacent to each other The sensing electrodes are combined to form a second sensing electrode group to perform a second self-capacitance sensing to obtain a second self-capacitance fingerprint sensing signal, where M and N are both positive integers greater than 1. The processing module is coupled to a sensing driver for generating a first self-capacitance fingerprint image and a second self-capacitance fingerprint image based on the first self-capacitance fingerprint sensing signal and the second self-capacitance fingerprint sensing signal, respectively. The first self-capacitance fingerprint image and the second self-capacitance fingerprint image are combined into a third self-capacitance fingerprint image. Wherein, the M sensing electrodes forming the first sensing electrode group and the N sensing electrodes forming the second sensing electrode group share at least one sensing electrode.

In one embodiment, the resolution of the third self-capacitance fingerprint image along at least one direction is greater than the resolution of the first self-capacitance fingerprint image and the second self-capacitance fingerprint image along the at least one direction.

In one embodiment, the sensing points of the first self-capacitance fingerprint image and the sensing points of the second self-capacitance fingerprint image are staggered and complementary to each other, so that the resolution of the third self-capacitance fingerprint image is higher than that of the first self-capacitance fingerprint image. Resolution of the capacitive fingerprint image or the second self-capacitive fingerprint image.

In one embodiment, the M sensing electrodes of the first sensing electrode group are formed. The poles are adjacent to each other in the horizontal, vertical, or oblique direction.

In one embodiment, the N sensing electrodes forming the second sensing electrode group are adjacent to each other in a horizontal direction, a vertical direction, or an oblique direction.

In one embodiment, the M sensing electrodes forming the first sensing electrode group are arranged as a matrix including P rows of sensing electrodes and Q columns of sensing electrodes, where M is a product of P and Q.

In one embodiment, the N sensing electrodes forming the second sensing electrode group are arranged as a matrix including R rows of sensing electrodes and S columns of sensing electrodes, where N is a product of S and T.

In one embodiment, the plurality of sensing electrodes have a geometric shape.

In one embodiment, the plurality of sensing electrodes have the same or different sizes or shapes.

In one embodiment, the regular arrangement of the plurality of sensing electrodes is a matrix arrangement, a triangular arrangement, or a staggered arrangement.

In one embodiment, the capacitive fingerprint sensing device further includes a switching module coupled between the sensing driver and the processing module. The switching module selectively switches the first self-capacitance sensing mode and the second self-capacitance sensing mode. The capacitance sensing mode transmits the first self-capacitance fingerprint sensing signal and the second self-capacitance fingerprint sensing signal to the processing module.

In one embodiment, the capacitive fingerprint sensing device further includes an amplification module, coupled between the switching module and the processing module, for amplifying the first fingerprint sensing signal and the second fingerprint sensing signal. After processing, it is sent to the processing module.

In one embodiment, in the first self-capacitance sensing mode and the second self-capacitance In the capacitive sensing mode, the sensing electrodes of the plurality of sensing electrodes that are not self-capacitance sensing are coupled to a shielding signal to avoid external noise interference.

In one embodiment, the shielding signal is a DC signal, an AC signal, a ground signal, or a sensing-related signal.

In one embodiment, the capacitive fingerprint sensing device further includes another sensing driver whose timing is complementary to the sensing driver. The sensing electrodes of the plurality of sensing electrodes that have not been subjected to self-capacitance sensing pass through another A sensing driver is coupled to the shielding signal.

In one embodiment, the capacitive fingerprint sensing device further includes a scan driver. The scanning driver is respectively coupled to a plurality of rows of sensing electrodes of the plurality of sensing electrodes through a plurality of scanning lines.

In one embodiment, the scan driver drives the plurality of rows of sensing electrodes through the plurality of scan lines in a sequential order.

In one embodiment, the scan driver drives a corresponding row of sensing electrodes of the plurality of rows of sensing electrodes only through one of the plurality of scanning lines at the same time.

In one embodiment, the scan driver drives the corresponding at least two rows of sensing electrodes of the plurality of rows of sensing electrodes through at least two scanning lines of the plurality of scanning lines at the same time.

In one embodiment, the scan driver drives the plurality of rows of sensing electrodes through the plurality of scan lines in a discontinuous order.

In one embodiment, the scan driver only passes through the scanner at the same time. One of the plurality of scan lines drives a corresponding one of the plurality of rows of sensing electrodes.

In one embodiment, the scan driver drives the corresponding at least two rows of sensing electrodes of the plurality of rows of sensing electrodes through at least two scanning lines of the plurality of scanning lines at the same time.

Compared with the prior art, the capacitive fingerprint sensing device according to the present invention performs self-capacitance sensing through different self-capacitance sensing electrode groups sharing at least one sensing electrode to obtain different self-capacitance fingerprint sensing maps, respectively. Image, and then combine the different self-capacitance fingerprint sensing images into a synthetic fingerprint sensing image, so that the resolution of the synthetic fingerprint sensing image along at least one direction will be greater than the different self-capacitance fingerprint sensing images The resolution along the at least one direction.

Therefore, the capacitive fingerprint sensing device according to the present invention can effectively increase the capacitance sensed by a unit sensing electrode without sacrificing its high resolution, thereby taking into account both fingerprint sensing capability and resolution requirements, effectively. Overcoming the shortcomings and limitations of traditional self-capacitance fingerprint sensing technology.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings.

1, 2, 2’‧‧‧‧ capacitive fingerprint sensing device

10, 20, 21‧‧‧ scan driver

12, 22‧‧‧ sensor driver

14, 24‧‧‧ processing module

26‧‧‧Switch Module

SE‧‧‧sensing electrode

Dx‧‧‧ X-direction spacing of sensing electrodes

Dy‧‧‧ Y-direction spacing of sensing electrodes

P1 ~ P25‧‧‧Sensing the center of gravity

G1 ~ G6, G1 ’~ G6’‧‧‧scan line

S1 ~ S6‧‧‧Sense line

T1 ~ T10‧‧‧Time

GS1 ~ GS6, GS1 ’~ GS6’‧‧‧scan drive signal

SS1 ~ SS6‧‧‧Sensor driving signal

L1 ~ L6‧‧‧ Conductor

SHD‧‧‧ Masking Signal

AR‧‧‧Fingerprint sensor array

MUX‧‧‧Multiplexer

IC‧‧‧ Controller

HOST‧‧‧Host

AMP‧‧‧amplification module

FIG. 1 is a schematic diagram showing a conventional capacitive fingerprint sensing device.

FIG. 2A is a schematic diagram of a capacitive fingerprint sensing device according to a preferred embodiment of the present invention.

FIG. 2B is a diagram illustrating a capacitor operating in a first self-capacitance sensing mode. Schematic diagram of the self-capacitance fingerprint sensing signal obtained by the self-capacitance sensing device with the self-capacitance sensing within the time T1 and having a position of the center of gravity P1 ~ P3.

FIG. 2C is a schematic diagram showing a self-capacitance fingerprint sensing signal obtained by performing self-capacitance sensing of the capacitive fingerprint sensing device operating in the first self-capacitance sensing mode within time T2 and having a position of the center of gravity P4 to P6. .

FIG. 2D shows the first self-capacitance fingerprint sensing signal obtained after the capacitive fingerprint sensing device operating in the first self-capacitance sensing mode sequentially performs self-capacitance sensing within time T1 to T5. Schematic diagram of the center of gravity positions P1 ~ P15.

FIG. 2E is a schematic diagram showing a self-capacitance fingerprint sensing signal obtained by performing self-capacitance sensing in a capacitive self-capacitance sensing device operating in the second self-capacitance sensing mode within time T6 and having a center of gravity position P16 ~ P17 .

FIG. 2F is a schematic diagram showing a self-capacitance fingerprint sensing signal obtained by performing self-capacitance sensing of a capacitive fingerprint sensing device operating in the second self-capacitance sensing mode within time T7 and having a center of gravity position P18 ~ P19 .

FIG. 2G is a diagram showing the second self-capacitance fingerprint sensing signal obtained after the capacitive fingerprint sensing device operating in the second self-capacitance sensing mode sequentially performs self-capacitance sensing within time T6 to T10. Schematic diagram of the center of gravity positions P16 ~ P25.

FIG. 2H shows the first self-capacitance fingerprint sensing image and the second self-capacitance fingerprint sensor obtained by operating the capacitive fingerprint sensing device in the first self-capacitance sensing mode and the second self-capacitance sensing mode, respectively. The measured image is synthesized as a schematic diagram of a third self-capacitance fingerprint image having a position of the center of gravity P1 to P25.

Figure 3A shows the scanning drive signals GS1 ~ GS6 and the sensing drive signals Timing chart of SS1 ~ SS6 in time T1 ~ T5.

FIG. 3B is a timing diagram of the scanning driving signals GS1 to GS6 and the sensing driving signals SS1 to SS6 within the time T6 to T10.

4A to 4D illustrate another embodiment of the capacitive fingerprint sensing device according to the present invention.

5A to 5B illustrate another embodiment of the capacitive fingerprint sensing device according to the present invention.

FIG. 6 is a schematic diagram illustrating a capacitive fingerprint sensing device including two scan drivers according to another preferred embodiment of the present invention.

FIG. 7 is a timing diagram of the sensing driving signals SS1 to SS6 and the scanning driving signals GS1 to GS6 and GS1 'to GS6' which are opposite to each other within time T6 to T10.

8A to 8D are schematic diagrams showing that the sensing electrodes are arranged in a regular manner and can have the same or different sizes or shapes.

FIG. 9A is a schematic diagram illustrating that the fingerprint sensor array AR is coupled to the host HOST through the multiplexer MUX and the controller IC.

FIG. 9B is a schematic diagram illustrating that the fingerprint sensor array AR is coupled to the host HOST through a multiplexer MUX provided in the controller IC.

FIG. 9C is a schematic diagram illustrating that the fingerprint sensor array AR is coupled to the host HOST through the multiplexer MUX, the amplification module AMP, and the controller IC.

A preferred embodiment of the present invention is a capacitive fingerprint sensing device. In this embodiment, the capacitive fingerprint sensing device can be operated at least separately In the first self-capacitance sensing mode and the second self-capacitance sensing mode. The capacitive fingerprint sensing device includes at least a plurality of sensing electrodes, a sensing driver, and a processing module. The sensing driver is coupled to the plurality of sensing electrodes. The processing module is coupled to the sensing driver. The plurality of sensing electrodes are arranged in a regular manner.

In the first self-capacitance sensing mode, the sensing driver selects M sensing electrodes adjacent to each other from the plurality of sensing electrodes to combine to form a first sensing electrode group and drives the first sensing electrode group to perform the first A self-capacitance sensing to obtain a first self-capacitance fingerprint sensing signal, wherein the M sensing electrodes are adjacent to each other in a horizontal direction, a vertical direction or an oblique direction; in the second self-capacitance sensing mode, The sensing driver selects N sensing electrodes adjacent to each other from the plurality of sensing electrodes to combine to form a second sensing electrode group and drives the second sensing electrode group to perform a second self-capacitance sensing to obtain a second The self-capacitance fingerprint sensing signal, wherein the N sensing electrodes are adjacent to each other in a horizontal direction, a vertical direction, or an oblique direction.

It should be noted that M and N are both positive integers greater than 1, and the M sensing electrodes forming the first sensing electrode group and the N sensing electrodes forming the second sensing electrode group share at least one sensing electrode. That is, one or more of the sensing electrodes in the first sensing electrode group driven by the sensing driver in the first self-capacitance sensing mode for self-capacitance sensing will still be in the second self-capacitance sensing mode. Will be driven by the sensing driver for self-capacitance sensing.

Then, the processing module generates a first self-capacitance fingerprint image and a second self-capacitance fingerprint image based on the first self-capacitance fingerprint sensing signal and the second self-capacitance fingerprint sensing signal, respectively, and converts the first self-capacitive fingerprint image Image with second self-capacitive fingerprint The image is synthesized into a third self-capacitance fingerprint image. The resolution of the third self-capacitance fingerprint image in at least one direction is greater than the resolution of the first self-capacitance fingerprint image and the second self-capacitance fingerprint image in the at least one direction.

That is, because the sensing points of the first self-capacitance fingerprint image and the sensing points of the second self-capacitance fingerprint image are staggered and complementary to each other, the processing module causes the first self-capacitance fingerprint image and the second self-capacitance fingerprint image After the fingerprint image is synthesized into the third self-capacitance fingerprint image, the resolution of the synthesized self-capacitance fingerprint image will be higher than that of the original self-capacitance fingerprint image, so it can achieve the improvement of the fingerprint sensing image. Specific power of resolution.

Next, the specific operation modes of the capacitive fingerprint sensing device of the present invention will be further described through the following different embodiments.

First, please refer to FIG. 2A, which is a schematic diagram illustrating a capacitive fingerprint sensing device according to a preferred embodiment of the present invention. As shown in FIG. 2A, the capacitive fingerprint sensing device 2 includes a scanning driver 20, a sensing driver 22, a processing module 24, a switching module 26, and a plurality of sensing electrodes SE. In this example, the capacitive fingerprint sensing device 2 can be operated in a first self-capacitance sensing mode or a second self-capacitance sensing mode. The plurality of sensing electrodes SE are arranged in a matrix of (6 × 6), that is, the sensing electrodes SE include six rows of sensing electrodes arranged in a vertical direction and six columns of sensing electrodes arranged in a horizontal direction. The scan driver 20 is respectively coupled to the first row of sensing electrodes to the sixth row of sensing electrodes through the scanning lines G1 to G6, and the switching module 26 is respectively coupled to the first row of sensing electrodes to the first row through the sensing lines S1 to S6. The six rows of sensing electrodes and selectively switch the sensing lines S1 to S6 are coupled or not coupled with the sensing driver 22, but not limited thereto.

In practical applications, the scan driver 20 may drive the first to sixth rows of sensing electrodes through the scan lines G1 to G6 in a sequential or discontinuous order. At the same time, the scan driver 20 can drive a corresponding row of sensing electrodes (such as the first row of sensing electrodes) only through a certain scanning line (such as scanning line G1), or it can also pass at least two scannings. Lines (such as scanning lines G1 to G2) simultaneously drive at least two rows of corresponding sensing electrodes (such as the first row of sensing electrodes to the second row of sensing electrodes), and there are no specific restrictions, depending on actual needs .

Next, please refer to both FIG. 2B and FIG. 3A. FIG. 2B shows the self-capacitance fingerprint sensing signal obtained by performing the self-capacitance sensing of the capacitive fingerprint sensing device 2 operating in the first self-capacitance sensing mode within the time T1 with a position of the center of gravity P1 ~ P3. Schematic diagram; FIG. 3A is a timing diagram of the scan driving signals GS1 to GS6 and the sensing driving signals SS1 to SS6 within time T1.

It can be known from FIG. 3A that within time T1, the scan drive signals GS1 to GS6 output by the scan driver 20 to the scan lines G1 to G6 respectively are only the scan drive signals GS1 and GS2 at a high level, and the remaining scans The driving signals GS3 ~ GS6 are all at a low level. That is, the scan driver 20 only turns on the scan lines G1 and G2 coupled to the first row of sensing electrodes and the second row of sensing electrodes, respectively, within the time T1. As for the switching module 26, within the time T1, the sensing lines S1 to S6 are switched, so that the sensing lines S1 and S2, the sensing lines S3 and S4, and the sensing lines S5 and S6 are connected to each other and coupled to the sensing respectively. The driver 22, so the sensing driving signals SS1 to SS6 can be transmitted to the first row sensing electrodes to the sixth row sensing electrodes through the sensing lines S1 to S6, respectively.

As shown in FIG. 2B, within time T1, the scanning lines G1 and G2 and the sensing The four sensing electrodes corresponding to the lines S1 and S2 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P1; the four sensing electrodes corresponding to the scanning lines G1 and G2 and the sensing lines S3 and S4 are The four sensing electrodes corresponding to the scanning lines G1 and G2 and the sensing lines S5 and S6 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P2. Position P3.

Similarly, please refer to FIG. 2C and FIG. 3A at the same time. FIG. 2C shows the self-capacitance fingerprint sensing signal obtained from the capacitive fingerprint sensing device 2 operating in the first self-capacitance sensing mode within the time T2 and having a position of the center of gravity P4 to P6. Schematic diagram; FIG. 3A is a timing diagram of the scan driving signals GS1 to GS6 and the sensing driving signals SS1 to SS6 within time T2.

It can be known from FIG. 3A that within time T2, the scan drive signals GS1 to GS6 output by the scan driver 20 to the scan lines G1 to G6 are only the scan drive signals GS2 and GS3 at the high level, and the remaining scans The drive signals GS1, GS4 ~ GS6 are all at a low level. That is, the scan driver 20 only turns on the scan lines G2 and G3 that are coupled to the second row of sensing electrodes and the third row of sensing electrodes, respectively, within time T2. As for the switching module 26, the sensing lines S1 and S2, the sensing lines S3 and S4, and the sensing lines S5 and S6 are connected to each other and coupled to the sensing driver 22 in time T2, so the sensing drive The signals SS1 to SS6 can be transmitted to the first row of sensing electrodes to the sixth row of sensing electrodes through the sensing lines S1 to S6, respectively.

As shown in FIG. 2C, within the time T2, the four sensing electrodes corresponding to the scanning lines G2 to G3 and the sensing lines S1 to S2 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P4; Four corresponding to lines G2 ~ G3 and sensing lines S3 ~ S4 The sensing electrodes are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P5; the four sensing electrodes corresponding to the scanning lines G2 to G3 and the sensing lines S5 to S6 are electrically connected to each other as a sensing electrode group and With sensing center of gravity position P6.

Next, the situation from time T3 to T5 can be deduced by analogy as above, and will not be repeated here.

When the capacitive fingerprint sensing device 2 is operated in the first self-capacitance sensing mode in sequence from time T1 to T5, the first self-capacitance fingerprint sensing signal shown in FIG. 2D is obtained. The position of the center of gravity P1 ~ P15 is sensed, and the first self-capacitance fingerprint sensing image can be obtained by the processing module 24 according to the first self-capacitance fingerprint sensing signal.

Please refer to FIG. 2E and FIG. 3B at the same time. FIG. 2E is a schematic diagram showing the self-capacitance fingerprint sensing signal obtained by performing self-capacitance sensing at time T6 of the capacitive fingerprint sensing device 2 operating in the second self-capacitance sensing mode, having a position of the center of gravity P16 ~ P17. ; FIG. 3B is a timing chart of the scanning driving signals GS1 to GS6 and the sensing driving signals SS1 to SS6 within time T6.

It can be known from FIG. 3B that within the time T6, the scan drive signals GS1 to GS6 output by the scan driver 20 to the scan lines G1 to G6 respectively are only the scan drive signals GS1 and GS2 at a high level, and the remaining scans The driving signals GS3 ~ GS6 are all at a low level. That is, the scan driver 20 only turns on the scan lines G1 and G2 that are respectively coupled to the first row of sensing electrodes and the second row of sensing electrodes within time T6. As for the switching module 26, within the time T6, the sensing lines S1 to S6 are switched, so that the sensing lines S2 and S3, the sensing lines S4 and S5 are connected to each other and coupled to the sensing driver 22, but the sensing The lines S1 and S6 are not coupled to the sensing driver 22, so only the sensing driving signals SS2 to SS5 among the sensing driving signals SS1 to SS6 are transmitted to the second row of sensing electrodes to the first through the sensing lines S2 to S5, respectively. There are five rows of sensing electrodes. As for the sensing lines S1 and S6, the sensing driving signals SS1 and SS6 are not transmitted to the first row sensing electrodes and the sixth row sensing electrodes.

As shown in FIG. 2E, within time T6, the four sensing electrodes corresponding to the scanning lines G1 to G2 and the sensing lines S2 to S3 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P16; The four sensing electrodes corresponding to the lines G1 to G2 and the sensing lines S4 to S5 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P17.

Similarly, please refer to FIG. 2F and FIG. 3B at the same time. FIG. 2F is a schematic diagram showing the self-capacitance fingerprint sensing signal obtained by performing self-capacitance sensing at time T7 of the capacitive fingerprint sensing device 2 operating in the second self-capacitance sensing mode, with a position of gravity center P18 ~ P19 ; FIG. 3B is a timing chart of the scanning driving signals GS1 to GS6 and the sensing driving signals SS1 to SS6 within time T7.

It can be known from FIG. 3B that within time T7, the scan drive signals GS1 to GS6 output by the scan driver 20 to the scan lines G1 to G6 respectively are only the scan drive signals GS2 and GS3 at a high level, and the remaining scans The drive signals GS1, GS4 ~ GS6 are all at a low level. That is, the scan driver 20 only turns on the scan lines G2 to G3 that are respectively coupled to the second row of sensing electrodes and the third row of sensing electrodes within time T7. As for the switching module 26, within the time T7, the sensing lines S1 to S6 are switched, so that the sensing lines S2 to S3 and the sensing lines S4 to S5 are connected to each other and coupled to the sensing driver 22, but the sensing line S1 and S6 are not coupled to the sensing driver 22, so only the sensing driving signals SS2 to SS5 among the sensing driving signals SS1 to SS6 are transmitted to the first through the sensing lines S2 to S5, respectively. The second row of sensing electrodes to the fifth row of sensing electrodes, as for the sensing lines S1 and S6, will not transmit the sensing driving signals SS1 and SS6 to the first row of sensing electrodes and the sixth row of sensing electrodes.

As shown in FIG. 2F, within time T7, the four sensing electrodes corresponding to the scanning lines G2 to G3 and the sensing lines S2 to S3 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P18; The four sensing electrodes corresponding to the lines G2 to G3 and the sensing lines S4 to S5 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P19.

The situation within the time T8 to T10 can be deduced by analogy as above, and it will not be repeated here.

When the capacitive fingerprint sensing device 2 is operated in the second self-capacitance sensing mode in sequence from time T6 to T10, the self-capacitance sensing can be performed to obtain a position with a center of gravity P16 to P25 as shown in FIG. 2G. The second self-capacitance fingerprint sensing signal can be obtained by the processing module 24 according to the second self-capacitance fingerprint sensing signal.

Then, as shown in FIG. 2H, the processing module 24 can operate the capacitive fingerprint sensing device in the first self-capacitance sensing mode and the first self-capacitance fingerprint sensing map obtained in the second self-capacitance sensing mode, respectively. The image and the second self-capacitance fingerprint sensing image are combined into a third self-capacitance fingerprint image having a sensing center of gravity position P1 to P25. Comparing FIG. 2D, FIG. 2G, and FIG. 2H, it can be seen that the resolution of the third self-capacitance fingerprint image after synthesis is significantly greater than the original first self-capacitance fingerprint sensing in the horizontal, vertical, and oblique directions. The resolution of the image and the second self-capacitance fingerprint sensing image in the horizontal direction, the vertical direction, and the oblique angle direction should meet the requirements of high resolution.

4A to 4D, FIG. 4A to FIG. 4D are drawings based on Another embodiment of the capacitive fingerprint sensing device of the present invention.

This embodiment is different from the foregoing embodiment in that: when the capacitive fingerprint sensing device 2 of this embodiment is operated in the first self-capacitance sensing mode, as shown in FIG. 4A, the scan driver 20 is scanned within time T1. The scan drive signals GS1 ~ GS3 output to the scan lines G1 ~ G3 are at a high level, and the scan drive signals GS4 ~ GS6 output to the scan lines G4 ~ G6 are at a low level. As for the switching module 26 at Within time T1, the sensing lines S1 to S6 are switched, so that the sensing lines S1 to S4 are connected to each other and coupled to the sensing driver 22, but the sensing lines S5 to S6 are not coupled to the sensing driver 22, so the sensing driving Among the signals SS1 to SS6, only the sensing driving signals SS1 to SS4 are transmitted to the first row of sensing electrodes to the fourth row of sensing electrodes through the sensing lines S1 to S4, respectively. As for the sensing lines S5 to S6, no sensing is transmitted The driving signals SS5 ~ SS6 to the fifth row of sensing electrodes and the sixth row of sensing electrodes. Therefore, within time T1, the twelve sensing electrodes corresponding to the scanning lines G1 to G3 and the sensing lines S1 to S4 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P1.

Similarly, when the capacitive fingerprint sensing device 2 is operated in the first self-capacitance sensing mode, as shown in FIG. 4B, the scanning driver 20 outputs the scanning driving signals to the scanning lines G2 to G4 within the time T2. GS2 ~ GS4 are at the high level, and the scan drive signals GS1, GS5 ~ GS6 output to the scanning lines G1, G5 ~ G6 are at the low level. As for the switching module 26, the sensing line S1 is maintained within the time T2. ~ S4 are connected to each other and coupled to the sensing driver 22 and the sensing lines S5 ~ S6 are not coupled to the sensing driver 22, so only the sensing driving signals SS1 ~ SS4 among the sensing driving signals SS1 ~ SS6 will pass through the sensing lines respectively. S1 ~ S4 are transmitted to the first row of sensing electrodes to the fourth row of sensing electrodes, as for the sensing line S5 ~ S6 will not transmit the sensing drive signals SS5 ~ SS6 to the fifth row of sensing electrodes and the sixth row of sensing electrodes. Therefore, within time T2, the twelve sensing electrodes corresponding to the scanning lines G2 to G4 and the sensing lines S1 to S4 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P2. As for the situation at the time T3 ~ T4, it can be deduced by analogy, so it will not be repeated here.

On the other hand, when the capacitive fingerprint sensing device 2 is operated in the second self-capacitance sensing mode, as shown in FIG. 4C, the scanning driver 20 outputs the scanning driving to the scanning lines G1 to G3 within the time T5. The signals GS1 ~ GS3 are at the high level, and the scan drive signals GS4 ~ GS6 output to the scanning lines G4 ~ G6 are at the low level. As for the switching module 26, the sensing lines S1 ~ S6 will be switched within the time T5. So that the sensing lines S2 to S5 are connected to each other and coupled to the sensing driver 22, but the sensing lines S1 and S6 are not coupled to the sensing driver 22, so only the sensing driving signal SS2 is among the sensing driving signals SS1 to SS6. ~ SS5 will be transmitted to the second row of sensing electrodes to the fifth row of sensing electrodes through the sensing lines S2 ~ S5. As for the sensing lines S1 and S6, the sensing driving signals SS1 and SS6 will not be transmitted to the first row of sensing electrodes. And the sixth row of sensing electrodes. Therefore, within time T5, the twelve sensing electrodes corresponding to the scanning lines G1 to G3 and the sensing lines S2 to S5 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P5.

Similarly, when the capacitive fingerprint sensing device 2 is operated in the second self-capacitance sensing mode, as shown in FIG. 4D, the scanning driver 20 outputs the scanning driving signals to the scanning lines G2 to G4 within the time T6. GS2 ~ GS4 are at the high level, and the scan drive signals GS1, GS5 ~ GS6 output to the scanning lines G1, G5 ~ G6 are at the low level. As for the switching module 26, the sensing line will be maintained within the time T6. S2 ~ S5 are connected to each other and coupled to The state that the sensing driver 22 and the sensing lines S1 and S6 are not coupled to the sensing driver 22 remains unchanged, so only the sensing driving signals SS2 to SS6 among the sensing driving signals SS1 to SS6 are transmitted through the sensing lines S2 to S5, respectively. From the second row of sensing electrodes to the fifth row of sensing electrodes, the sensing lines S1 and S6 do not transmit the sensing driving signals SS1 and SS6 to the first row of sensing electrodes and the sixth row of sensing electrodes. Therefore, within time T6, the twelve sensing electrodes corresponding to the scanning lines G2 to G4 and the sensing lines S2 to S5 are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P6. As for the situation of time T7 ~ T8, it can be deduced by analogy, so it will not be repeated here.

Similarly, the processing module 24 can operate the capacitive fingerprint sensing device 2 in the first self-capacitance sensing mode and the first self-capacitance sensing image obtained in the second self-capacitance sensing mode and the second self-capacitance fingerprint sensing image, respectively. The self-capacitance fingerprint sensing image is synthesized into a third self-capacitance fingerprint image with a higher resolution.

5A to 5B, FIG. 5A to FIG. 5B illustrate another embodiment of the capacitive fingerprint sensing device according to the present invention.

As shown in FIG. 5A, when the capacitive fingerprint sensing device 2 of this embodiment is operated in the first self-capacitance sensing mode, within a time T1, the scan driver 20 outputs to the scan drivers of the scan lines G1 to G3. The signals GS1 ~ GS3 are at the high level, and the scan drive signals GS4 ~ GS6 output to the scan lines G4 ~ G6 are at the low level. As for the switching module 26, the sensing line S1 ~ S6 will be switched within the time T1 So that the sensing lines S1 ~ S3, S4 ~ S6 are connected and coupled to the sensing driver 22 respectively, so the sensing driving signals SS1 ~ SS6 will be transmitted to the first row of sensing electrodes through the sixth column through the sensing lines S1 ~ S6, respectively. Sense electrode. Therefore, within time T1, the scanning lines G1 to G3 and the sensing lines S1 to S3 The corresponding 9 sensing electrodes are electrically connected to each other as a sensing electrode group and have a sensing center of gravity position P1, and the 9 sensing electrodes corresponding to the scanning lines G1 to G3 and the sensing lines S4 to S6 are electrically connected to each other. It is connected to another sensing electrode group and has a sensing center of gravity position P2.

Similarly, as shown in FIG. 5B, within the time T2, the scan driver signals GS3 to GS5 output to the scan lines G3 to G5 are at a high level and output to the scan lines G1 to G2, G6. The scanning drive signals GS1 ~ GS2, GS6 are at a low level. As for the switching module 26 within the time T2, the sensing lines S1 ~ S3, S4 ~ S6 are respectively maintained and coupled to the state of the sensing driver 22, Therefore, the sensing driving signals SS1 to SS6 are transmitted to the first row sensing electrodes to the sixth row sensing electrodes through the sensing lines S1 to S6, respectively. Therefore, within time T2, the nine sensing electrodes corresponding to the scanning lines G3 to G5 and the sensing lines S1 to S3 will be electrically connected to each other as a sensing electrode group with a sensing center of gravity position P3, and the scanning line G3 The nine sensing electrodes corresponding to ~ G5 and the sensing lines S4 ~ S6 are electrically connected to each other as another sensing electrode group and have a sensing center of gravity position P4.

Next, please refer to FIG. 6. FIG. 6 illustrates an embodiment in which the capacitive fingerprint sensing device 2 ′ includes two scan drivers 20 and 21. In this embodiment, as shown in FIG. 6, the capacitive fingerprint sensing device 2 ′ includes two scanning drivers 20 to 21, a sensing driver 22, a processing module 24, a switching module 26, and a plurality of sensing electrodes. SE. The plurality of sensing electrodes SE are arranged in a matrix form of (6 × 6). The capacitive fingerprint sensing device 2 can be operated in a first self-capacitance sensing mode or a second self-capacitance sensing mode. The timings of the scan drivers 20 and 21 are complementary to each other, that is, the scan driving signals sent by the scan drivers 20 and 21 are inverse to each other.

The switching module 26 is coupled to the first line of sensing through the sensing lines S1 to S6, respectively. The electrodes to the sixth row of sensing electrodes and selectively switch the sensing lines S1 to S6 to be coupled or not coupled to the sensing driver 22. The scan driver 20 is coupled to the first row of sensing electrodes to the sixth row of sensing electrodes through the scanning lines G1 to G6, and the scanning lines G1 to G6 and the sensing lines S1 to S6 are respectively coupled to the plurality of sensing electrodes. Electrode SE. The sensing electrodes in the first row to the sensing electrodes in the sixth row are respectively coupled to the shielding signal SHD through the wires L1 to L6. When the scan driver 21 is coupled to the first row of sensing electrodes through the sixth row of sensing electrodes through the scan lines G1 '~ G6', the scan lines G1 '~ G6' and the wires L1 ~ L6 are respectively coupled to the The plurality of sensing electrodes SE are not limited thereto.

In addition, the switching module 26 is also coupled to the shielding signal SHD. When the switching module 26 selectively switches the sensing lines S1 to S6 to be coupled or uncoupled to the sensing driver 22, the sensing lines S2 and S3, and the sensing lines S4 and S5 are connected to each other in pairs and are respectively coupled to The sensing driver 22 is configured to drive the second row of sensing electrodes to the third row of sensing electrodes, the fourth row of sensing electrodes to the fifth row of sensing electrodes for self-capacitance sensing, and the sensing lines S1 and S6 are not coupled. To the sensing driver 22, the first row of sensing electrodes and the sixth row of sensing electrodes are not driven for self-capacitance sensing.

In practice, in order to prevent the first row of sensing electrodes and the sixth row of sensing electrodes from being interfered by external noise without self-capacitance sensing, the sensing lines S1 and S6 is coupled to the shielding signal SHD through the scanning driver 21 or the switching module 26, and the shielding signal SHD may be a DC signal, an AC signal, a ground signal, or a sensing-related signal, but is not limited thereto.

Please refer to FIG. 7. FIG. 7 shows the sensing driving signals SS1 to SS6 and the scanning driving signals GS1 to GS6 and GS1 ’to GS6’ which are opposite to each other and the time between T6 to T10. Timing diagram. Because the timings of the scan drivers 20 and 21 are complementary to each other, the scan drive signal GS1 issued by the scan driver 20 and the scan drive signal GS1 ′ issued by the scan driver 21 are inverse to each other; The scan driving signal GS2 sent out and the scan driving signal GS2 'sent out by the scan driver 21 are opposite to each other; the rest can be deduced by analogy, so it will not be repeated here.

8A to 8D. It can be known from FIG. 8A to FIG. 8D that the sensing electrodes SE are arranged in a regular manner and may have the same or different sizes or shapes, and there are no specific restrictions. For example, the shape of the sensing electrode SE is not limited to the square in the previous embodiment, but may also be a parallelogram in FIG. 8A, a hexagon in FIG. 8B, a circle in FIG. 8C, and a circle in FIG. 8D. Triangles or other geometric shapes may be arranged in a regular manner.

Please also refer to FIGS. 9A to 9C. As shown in FIG. 9A, the fingerprint sensor array AR can be coupled to the host HOST through the multiplexer MUX and the controller IC, so that the host HOST processes the fingerprint sensing signal received by the controller IC; as shown in FIG. 9B, The fingerprint sensor array AR can be coupled to the host HOST through a multiplexer MUX integrated in the controller IC; as shown in FIG. 9C, an amplifier module AMP can also be provided between the multiplexer MUX and the controller IC. In fact, the amplification module AMP can be fabricated on a glass substrate or integrated in a controller IC, but it is not limited to this.

Compared with the prior art, the capacitive fingerprint sensing device according to the present invention performs self-capacitance sensing through different self-capacitance sensing electrode groups sharing at least one sensing electrode, so as to obtain different self-capacitance fingerprint sensing respectively. Image, and then combine these different self-capacitance fingerprint sensing images into a synthetic fingerprint sensing image, so that The resolution of the synthetic fingerprint sensing image along at least one direction is greater than the resolution of different self-capacitance fingerprint sensing images along the at least one direction.

Therefore, the capacitive fingerprint sensing device according to the present invention can effectively increase the capacitance sensed by a unit sensing electrode without sacrificing its high resolution, thereby taking into account both fingerprint sensing capability and resolution requirements, effectively. Overcoming the shortcomings and limitations of traditional self-capacitance fingerprint sensing technology.

From the detailed description of the above preferred embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patents to be applied for in the present invention. With the above detailed description of the preferred embodiments, it is hoped that the features and spirit of the present invention can be more clearly described, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patents to be applied for in the present invention.

Claims (22)

A capacitive fingerprint sensing device can be operated in a first self-capacitance sensing mode and a second self-capacitance sensing mode, respectively. The capacitive fingerprint sensing device includes: a plurality of sensing electrodes, with regularity The sensor driver is coupled to the plurality of sensing electrodes. In the first self-capacitance sensing mode, the sensing driver selects M sensing electrodes adjacent to each other among the plurality of sensing electrodes. Combined to form a first sensing electrode group to perform a first self-capacitance sensing to obtain a first self-capacitance fingerprint sensing signal; in the second self-capacitance sensing mode, the sensing driver selects the plurality of The N sensing electrodes adjacent to each other in the sensing electrodes are combined to form a second sensing electrode group to perform a second self-capacitance sensing to obtain a second self-capacitance fingerprint sensing signal, where M and N are both A positive integer greater than 1; and a processing module coupled to the sensing driver for generating a first self-capacitance fingerprint image based on the first self-capacitance fingerprint sensing signal and the second self-capacitance fingerprint sensing signal, respectively Like with a second self-capacitance finger Image and synthesize the first self-capacitance fingerprint image and the second self-capacitance fingerprint image into a third self-capacitance fingerprint image; wherein the M sensing electrodes and the first sensing electrode group forming the The N sensing electrodes forming the second sensing electrode group share at least one sensing electrode. The capacitive fingerprint sensing device according to item 1 of the scope of patent application, wherein the resolution of the third self-capacitive fingerprint image in at least one direction is greater than the first self-capacitive fingerprint image and the second self-capacitive fingerprint image. The resolution of the image along the at least one direction. The capacitive fingerprint sensing device according to item 1 of the scope of patent application, wherein the sensing points of the first self-capacitance fingerprint image and the sensing points of the second self-capacitance fingerprint image are staggered and complementary with each other, so that the The resolution of the third self-capacitance fingerprint image is higher than the resolution of the first self-capacitance fingerprint image or the second self-capacitance fingerprint image. The capacitive fingerprint sensing device according to item 1 of the scope of the patent application, wherein the M sensing electrodes forming the first sensing electrode group are adjacent to each other in a horizontal direction, a vertical direction, or an oblique direction. The capacitive fingerprint sensing device according to item 1 of the scope of the patent application, wherein the N sensing electrodes forming the second sensing electrode group are adjacent to each other in a horizontal direction, a vertical direction, or an oblique direction. The capacitive fingerprint sensing device described in item 1 of the scope of the patent application, wherein the M sensing electrodes forming the first sensing electrode group are arranged in a matrix including P-row sensing electrodes and Q-row sensing electrodes. , Where M is the product of P and Q, and P and Q are both positive integers greater than 1. The capacitive fingerprint sensing device described in item 1 of the scope of patent application, wherein the N sensing electrodes forming the second sensing electrode group are arranged in a matrix including R rows of sensing electrodes and S rows of sensing electrodes. , Where N is the product of S and R, and R and S are both positive integers greater than 1. The capacitive fingerprint sensing device according to item 1 of the scope of patent application, wherein the plurality of sensing electrodes have a geometric shape. The capacitive fingerprint sensing device according to item 1 of the scope of the patent application, wherein the plurality of sensing electrodes have the same or different sizes or shapes. The capacitive fingerprint sensing device according to item 1 of the scope of the patent application, wherein the regular arrangement of the plurality of sensing electrodes is a matrix arrangement, a triangular arrangement, or a staggered arrangement. The capacitive fingerprint sensing device described in item 1 of the scope of the patent application, further comprising: a switching module coupled between the sensing driver and the processing module, the switching module selectively switching the first A self-capacitance sensing mode and the second self-capacitance The sensing mode transmits the first self-capacitance fingerprint sensing signal and the second self-capacitance fingerprint sensing signal to the processing module, wherein the switching module is a multiplexer and the sensing driver is a fingerprint sensor. Sensor array, the processing module is a controller. The capacitive fingerprint sensing device according to item 11 of the scope of the patent application, further comprising: an amplification module coupled between the switching module and the processing module for sensing the first self-capacitance fingerprint. The measurement signal and the second self-capacitance fingerprint sensing signal are amplified and transmitted to the processing module. The capacitive fingerprint sensing device according to item 1 of the scope of the patent application, wherein in the first self-capacitance sensing mode and the second self-capacitance sensing mode, no self-capacitance is performed in the plurality of sensing electrodes. The sensing electrode is coupled to a shielding signal to avoid external noise interference. The capacitive fingerprint sensing device described in item 13 of the scope of the patent application, wherein the masking signal is a direct current signal, an AC signal, a ground signal, or a sensing-related signal. The capacitive fingerprint sensing device according to item 13 of the scope of the patent application, further comprising: another sensing driver, the timing of the other sensing driver and the sensing driver are complementary to each other, and the other sensing driver and The scanning driving signals sent by the sensing driver are opposite to each other. The sensing electrodes of the plurality of sensing electrodes that are not self-capacitance sensing are coupled to the shielding signal through the other sensing driver. The capacitive fingerprint sensing device described in item 1 of the scope of the patent application, further includes: a scanning driver, which is coupled to a plurality of sensing electrodes of the plurality of sensing electrodes through a plurality of scanning lines, respectively. The capacitive fingerprint sensing device according to item 16 of the patent application scope, wherein the scanning The driver drives the plurality of rows of sensing electrodes through the plurality of scanning lines in a sequential order. The capacitive fingerprint sensing device according to item 17 of the scope of the patent application, wherein the scan driver drives the corresponding ones of the plurality of sensing electrodes only through one of the plurality of scanning lines at the same time. A row of sensing electrodes. The capacitive fingerprint sensing device according to item 18 of the scope of patent application, wherein the scan driver drives the phases in the plurality of sensing electrodes through at least two scanning lines of the plurality of scanning lines at the same time. Corresponding at least two rows of sensing electrodes. The capacitive fingerprint sensing device according to item 16 of the scope of the patent application, wherein the scanning driver drives the plurality of rows of sensing electrodes through the plurality of scanning lines in a discontinuous order. The capacitive fingerprint sensing device described in item 20 of the scope of patent application, wherein the scan driver drives the corresponding ones of the plurality of rows of sensing electrodes only through one of the plurality of scan lines at the same time. A row of sensing electrodes. The capacitive fingerprint sensing device according to item 20 of the scope of patent application, wherein the scan driver drives the phases in the plurality of sensing electrodes through at least two scanning lines of the plurality of scanning lines at the same time. Corresponding at least two rows of sensing electrodes.