Optical fingerprint sensing device and driving device and operation method thereof

Abstract

The present invention provides an optical fingerprint sensing device, a driving device and an operation method. The driving device includes a display driving device and a fingerprint sensing driving device. The display driving device drives a display panel to display different frames with different brightness, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities. The fingerprint sensing driving device is used to drive the display panel to perform a fingerprint capture operation to capture multiple different fingerprint images of a finger under the conditions of at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are processed to generate processed fingerprint images.

Description

Technical Field

[0001] The present invention relates to a fingerprint sensing device, and in particular to an optical fingerprint sensing device, a driving device and an operating method. Background Art

[0002] Recently, optical fingerprint sensing devices have adopted full-screen (or large-screen) optical fingerprint sensing technology. Users can press their fingers anywhere on the display panel to facilitate optical fingerprint sensing. In the process of capturing fingerprint images, the display panel can display a light spot (speckle) to supply light source (incident light) to the user's finger. The reflected light of the finger can be sensed by the display panel. Generally speaking, the brightness of the reflected light of the peaks in the fingerprint is greater than the brightness of the reflected light of the valleys in the fingerprint. Therefore, the display panel can capture the fingerprint image. However, ambient light may affect the fingerprint sensing of the optical fingerprint sensing device. Generally speaking, the stronger the ambient light, the more likely it is that the fingerprint recognition will fail.

[0003] For example, when optical fingerprint sensing is performed in strong ambient light, the strong ambient light can easily penetrate the finger and be sensed by the display panel. In this case, the fingerprint sensing result of the display panel includes a reflected light component and a transmitted light component. The reflected light component is the sensing target. The reflected light component is generated after the light spot displayed by the display panel is irradiated to the finger. Generally speaking, for the reflected light component, the brightness of the peaks in the fingerprint is greater than the brightness of the valleys in the fingerprint. The transmitted light component is generated by the strong ambient light that penetrates the finger. Generally speaking, for the transmitted light component, the brightness of the peaks in the fingerprint is less than the brightness of the valleys in the fingerprint. The transmitted light component will interfere with (affect) the reflected light component. Therefore, strong ambient light can easily cause fingerprint signal drift (abnormality), which in turn causes the subsequent circuit to be unable to analyze the fingerprint signal. Summary of the invention

[0004] The present invention provides an optical fingerprint sensing device, a driving device and an operating method to reduce the negative impact of ambient light on fingerprint sensing.

[0005] According to an embodiment of the present invention, the driving device includes a display driving device and a fingerprint sensing driving device. The display driving device is coupled to the display panel. The display driving device is used to drive the display panel to display different frames with different brightness, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities. The fingerprint sensing driving device is coupled to the display panel. The fingerprint sensing driving device is used to drive the display panel to perform a fingerprint capture operation to capture multiple different fingerprint images of the finger under the conditions of at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are processed to generate processed fingerprint images.

[0006] According to an embodiment of the present invention, the above-mentioned optical fingerprint sensing device includes a display panel and a driving device. The display panel is used to perform a fingerprint capture operation on the finger when the finger contacts the display panel. The driving device includes a display driving device and a fingerprint sensing driving device. The display driving device is coupled to the display panel. The display driving device is used to drive the display panel to display different frames with different brightness, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities. The fingerprint sensing driving device is used to couple to the display panel to drive the display panel to perform a fingerprint capture operation. The fingerprint sensing driving device is used to capture multiple different fingerprint images of the finger under the condition of at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are processed to generate processed fingerprint images.

[0007] According to an embodiment of the present invention, the above-mentioned operating method includes: when a finger contacts the display panel, driving the display panel to display different frames, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities; and driving the display panel to perform a fingerprint capture operation to capture multiple different fingerprint images of the finger under the conditions of at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are processed to generate a processed fingerprint image.

[0008] Based on the above, the fingerprint sensing driving device described in the embodiments of the present invention can capture multiple different fingerprint images of the same finger under different transmitted light intensities and / or different reflected light intensities. The optical fingerprint sensing device can process these different fingerprint images to generate a processed fingerprint image to reduce the negative impact of ambient light on fingerprint sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of an operation scenario of an optical fingerprint sensing device.

[0010] Figure 2 FIG. 4 is a schematic diagram of a circuit block of an optical fingerprint sensing device according to an embodiment of the present invention.

[0011] Figure 3 According to an embodiment of the present invention, Figure 2 The circuit block diagram of the display panel and the fingerprint sensing driving device is shown.

[0012] Figure 4 According to an embodiment Figure 3 Timing diagram of the signals shown.

[0013] Figure 5It is a flowchart of an operating method of an optical fingerprint sensing device according to an embodiment of the present invention.

[0014] Figure 6 It is a schematic diagram of capturing two fingerprint images under different light frame brightness conditions of a fingerprint sensing driving device according to an embodiment of the present invention.

[0015] Figure 7 FIG. 1 is a diagram showing a relationship curve between the brightness of ambient light and the sensing result of a fingerprint sensing driving device according to an embodiment of the present invention.

[0016] Figure 8 FIG. 4 is a schematic diagram illustrating frames displayed by a display panel according to an embodiment of the present invention.

[0017] Description of Reference Numerals

[0018] 200: Optical fingerprint sensor device

[0019] 210: Display Panel

[0020] 210_1, 210_2, 210_3, 210_N: sub-areas

[0021] 220: Drive equipment

[0022] 221: Fingerprint sensing drive device

[0023] 222: Display driver

[0024] 230: Processor

[0025] 810: Fingers

[0026] 820: Ring light spot

[0027] 830: Ambient Light

[0028] FI: Sensing result

[0029] Frame1, Frame2: fingerprint images

[0030] L1, L2: Relationship curve

[0031] L_amb: Brightness of ambient light

[0032] P: Optical sensing pixel

[0033] Prd: Fingerprint frame reading period

[0034] Prst: Fingerprint frame reset period

[0035] Ro1, Ro2, Ro3, Ro4: source lines

[0036] RST: Fingerprint frame reset operation

[0037] Rst0, Rst1, Rst2, Rst3, Rst(n-1): reset scan signal

[0038] RstClk: reset clock

[0039] RstStart[1], RstStart[1:N]: reset start pulse

[0040] S510, S520, S530: Steps

[0041] Sel0, Sel1, Sel2, Sel3, Sel(n-1): read scan signal

[0042] SelClk: Read clock

[0043] SelStart[1:N]: Select the start pulse

[0044] SIG: Fingerprint frame reading operation

[0045] SR: Shift Register

[0046] Texp: exposure time DETAILED DESCRIPTION

[0047] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0048] The term "coupled (or connected)" used in the entire specification of this case (including the claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be indirectly connected to the second device through other devices or some connection means. The terms "first", "second", etc. mentioned in the entire specification of this case (including the claims) are used to name the components (element) or to distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of components, nor to limit the order of components. In addition, wherever possible, components / components / steps with the same number in the drawings and embodiments represent the same or similar parts. Components / components / steps using the same number or the same terminology in different embodiments can refer to the relevant descriptions of each other.

[0049] The following uses multiple embodiments to illustrate multiple countermeasures for fingerprint recognition in strong ambient light. In some embodiments, the driving device can perform multiple optical fingerprint sensing on the same fingerprint through the display panel to obtain multiple fingerprint images, and use these fingerprint images to reduce the transmitted light component generated by the ambient light, thereby avoiding fingerprint signal drift as much as possible.

[0050] Figure 1 is a schematic diagram of an operation scenario of the optical fingerprint sensing device 200. Figure 2 FIG. 1 is a circuit block diagram of an optical fingerprint sensing device 200 according to an embodiment of the present invention. Figure 1 and Figure 2 The optical fingerprint sensing device 200 shown includes a display panel 210 and a driving device 220. When a finger contacts a touch area of ​​the display panel 210, the display panel 210 can perform a fingerprint capture operation on the fingerprint sensing area corresponding to the touch area. The present embodiment does not limit the implementation details of the display panel 210. For example, the display panel 210 may include a conventional display panel or other display panels with fingerprint sensing functions. According to different design requirements, the driving device 220 may be implemented in hardware, firmware, software (i.e., program), or a combination of more than one of the above three.

[0051] In terms of hardware, the driver device 220 can be implemented as a logic circuit on an integrated circuit. The functions of the driver device 220 can be implemented as hardware using hardware description languages ​​(such as Verilog HDL or VHDL) or other suitable programming languages. For example, the functions of the driver device 220 can be implemented in various logic blocks, modules and circuits in one or more controllers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs) and / or other processing units.

[0052] In software form and / or firmware form, the relevant functions of the drive device 220 can be implemented as programming codes. For example, the drive device 220 is implemented using general programming languages ​​(such as C, C++ or assembly language) or other suitable programming languages. The programming codes can be recorded / stored in a "non-transitory computer readable medium". In some embodiments, the non-transitory computer readable medium includes, for example, a read-only memory (ROM), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit and / or a storage device. The storage device includes a hard disk drive (HDD), a solid-state drive (SSD) or other storage devices. A central processing unit (CPU), a controller, a microcontroller or a microprocessor can read and execute the programming codes from the recording medium to implement the relevant functions of the drive device 220.

[0053] The driving device 220 includes a fingerprint sensing driving device 221 and a display driving device 222. The display driving device 222 is coupled to the display panel 210. The display driving device 222 can drive the display panel 210 to display different frames with different brightness. The different frames are used to generate different transmitted light intensities and (or) different reflected light intensities. The implementation details of the display driving device 222 are not limited here. According to the actual design, in some embodiments, the display driving device 222 may include a conventional display driving circuit or other display driving circuits. For example, in other embodiments, the display driving device 222 may include a timing controller, a source driver, and a gate driver (all not shown). Figure 2 ).

[0054] The fingerprint sensing driving device 221 is coupled to the display panel 210. The fingerprint sensing driving device 221 can drive the display panel 210 to perform a fingerprint capture operation on the finger and capture (obtain) the fingerprint image of the finger. Based on the display driving device 222 driving the display panel 210, the fingerprint sensing driving device 221 can capture multiple different fingerprint images of the same finger under different transmitted light intensities and (or) different reflected light intensities, and then provide / transmit these fingerprint images to the processor 230. The processor 230 can process the different fingerprint images to generate a processed fingerprint image to reduce the negative impact of ambient light on fingerprint sensing. The processor 230 can use the processed fingerprint image for fingerprint recognition.

[0055] Figure 3 According to an embodiment of the present invention, Figure 2 The circuit block diagram of the display panel 210 and the fingerprint sensing driving device 221 is shown. Figure 1 and Figure 3 . The optical sensing pixel array of the display panel 210 includes a plurality of optical sensing pixels P. The present embodiment does not limit the implementation details of the optical sensing pixel P. According to the actual design, in some embodiments, the optical sensing pixel P may be a conventional optical sensing pixel that illustrates other optical sensing pixels. One or more fingers of the user may be pressed on the display panel 210 of the optical fingerprint sensing device 200. The optical sensing pixel array of the display panel 210 may sense the fingerprint of this (these) finger(s). Therefore, when the finger contacts the display panel 210, the display panel 210 may perform a fingerprint capture operation on the finger. The fingerprint sensing drive device 221 is coupled to the display panel 210. The fingerprint sensing drive device 221 may drive the display panel 210 to perform a fingerprint capture operation on the finger and capture (obtain) a fingerprint image of the finger.

[0056] exist Figure 2 In the illustrated embodiment, the display panel 210 may be divided into N sub-areas 210_1, 210_2, 210_3, ..., 210_N, where N is an integer determined according to actual design. The shift register SR may be configured on the display panel 210. The fingerprint sensing driving device 221 may output a reset clock RstClk and N reset start pulses RstStart[1:N] to some shift registers SR (such as Figure 3 According to the timing of the reset clock RstClk and the reset start pulse RstStart[1:N], some shift registers SR can output scan signals to scan the optical sensing pixels P of the optical sensing pixel array of the display panel 210 .

[0057] For example, Figure 4 According to an embodiment Figure 3See the timing diagram of the signal shown. Figure 3 and Figure 4 . According to the timing of the reset clock RstClk and the reset start pulse RstStart[1], the shift register SR in the sub-area 210_1 can output n reset scan signals Rst0, Rst1, Rst2, Rst3, ..., Rst(n-1), where n is an integer determined according to the actual design. The other sub-areas 210_2 to 210_N can be deduced by referring to the relevant description of the sub-area 210_1, so they are not repeated here. Based on the scanning timing of the reset scan signals Rst0 to Rst(n-1), the optical sensing pixel array in the sub-area 210_1 of the display panel 210 can perform a complete reset scan operation. The period during which the optical sensing pixel array performs a complete reset scan operation can be referred to as the fingerprint frame reset period Prst.

[0058] The fingerprint sensing driving device 221 can output a read clock (selection clock) SelClk and N selection start pulses SelStart[1:N] to other shift registers SR (such as Figure 3 As shown). According to the timing of the read clock SelClk and the selection start pulse SelStart[1:N], the shift registers SR can output the read scan signal to scan the optical sensing pixels P of the optical sensing pixel array of the display panel 210. For example, according to the timing of the read clock SelClk and the selection start pulse SelStart[1:N], the shift registers SR in the sub-area 210_1 can output the read scan signals Sel0, Sel1, Sel2, Sel3, ..., Sel(n-1) to scan the optical sensing pixels P of the optical sensing pixel array of the display panel 210. Based on the scan timing of the read scan signals Sel0 to Sel(n-1), the fingerprint sensing driving device 221 can sense (read) the light sensing results of the optical sensing pixels P via the source lines (sensing lines) Ro1, Ro2, Ro3 and Ro4 of the display panel 210. The period during which the optical sensing pixel array performs a complete read scan operation can be referred to as the fingerprint frame read period Prd.

[0059] for Figure 3For the first row of optical sensing pixels P shown, the time from the pulse of the reset scan signal Rst0 (the first row of optical sensing pixels P is reset) to the pulse of the read scan signal Sel0 (the first row of optical sensing pixels P is read) is the exposure time Texp of the first row of optical sensing pixels P. The fingerprint sensing driving device 221 can dynamically adjust the exposure time Texp according to the ambient light. The fingerprint sensing driving device 221 can shorten the exposure time Texp as much as possible, and even partially overlap the fingerprint frame reading period Prd with the fingerprint frame reset period Prst in time. After completing the fingerprint frame reset period Prst and the fingerprint frame reading period Prd, the fingerprint sensing driving device 221 can capture a fingerprint image of the finger.

[0060] Figure 5 FIG. 1 is a flow chart of an operation method of an optical fingerprint sensing device according to an embodiment of the present invention. Figure 2 and Figure 5 When the finger contacts the display panel 210, in step S510, the display driving device 222 controlled by the processor 230 may drive the display panel 210 to generate / display different frames, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities. According to actual design, in some embodiments, the different frames have at least one feature, including at least one of shape, area, global brightness, local brightness, and quantity, to generate the different transmitted light intensities and (or) the different reflected light intensities.

[0061] In step S520, the fingerprint sensing driving device 221 can drive the display panel 210 to perform a fingerprint capture operation to capture multiple different fingerprint images of the same finger under the conditions of different transmitted light intensities and / or different reflected light intensities. Based on the display driving device 222 driving the display panel 210, the fingerprint sensing driving device 221 can capture multiple different fingerprint images of the same finger under the conditions of different transmitted light intensities and / or different reflected light intensities, and then provide / transmit these fingerprint images to the processor 230.

[0062] In step S530, the processor 230 may process the different fingerprint images to generate processed fingerprint images to reduce the negative impact of ambient light on the processed fingerprint images. Any of the different fingerprint images includes: a reflected light component contributed by the different frames displayed by the display panel 210 and a transmitted light component contributed by ambient light. The different frames displayed by the display panel 210 are used to generate different intensities of the reflected light components of different fingerprint images. After obtaining a plurality of fingerprint images with different reflected light components, the processor 230 may perform a subtraction operation on these fingerprint images to generate a processed fingerprint image to reduce the negative impact of ambient light on the processed fingerprint image. The processor 230 may use the processed fingerprint image for fingerprint recognition.

[0063] For example (but not limited to this), the touch driving device (not shown) can detect the touch position of the finger on the display panel 210, and then the touch driving device can report the relevant information of the touch position to the processor 230. In some embodiments, according to the touch position, the processor 230 can add a light spot pattern to the image frame, and then transmit the image frame with the light spot pattern added to the display driving device 222. Or, in other embodiments, the processor 230 can provide the touch position and the image frame to the display driving device 222, and then the display driving device 222 can add the light spot pattern to the image frame according to the touch position. The display driving device 222 can drive the display panel 210 to display the image frame (a plurality of image frames with different brightness) with the light spot pattern added. In the process of the display panel 210 displaying a plurality of image frames with different brightness, the fingerprint sensing driving device 221 can capture a plurality of fingerprint images and provide these fingerprint images to the processor 230. The processor 230 can process these fingerprint images to generate processed fingerprint images, and then use the processed fingerprint images for fingerprint recognition.

[0064] For example, the user can press a finger anywhere on the display panel 210 to facilitate optical fingerprint sensing. In the process of capturing the fingerprint image, the display panel 210 can display a default frame (such as a light spot) to supply a light source (incident light) to the user's finger. The optical sensing pixel array of the display panel 210 can sense the reflected light of the finger to capture the fingerprint image. Generally speaking, the brightness of the reflected light of the fingerprint's peak is greater than the brightness of the reflected light of the fingerprint's valley. Under normal ambient light, it is extremely difficult for ambient light to penetrate the finger, or the ambient light that penetrates the finger is very weak (the optical sensing pixel array of the display panel 210 cannot sense it). In this case, the fingerprint sensing result (fingerprint image A) of the display panel 210 includes a reflected light component RV, as shown in the following formula 1. The reflected light component RV is related to the reflected light generated after the light frame of the display panel 210 is irradiated to the finger.

[0065] Fingerprint image A = RV Formula 1

[0066] When the display panel 210 performs optical fingerprint sensing in strong ambient light, the strong ambient light may penetrate the finger and be sensed by the optical sensing pixel array of the display panel 210. The display panel 210 can display a default frame (e.g., a light spot) to supply a light source (incident light) to the finger, while the strong ambient light simultaneously penetrates the finger to the display panel 210. In this case, the fingerprint sensing result (fingerprint image B) of the display panel 210 includes a reflected light component RV and a transmitted light component -RV2, as shown in the following formula 2.

[0067] The reflected light component RV is related to the reflected light generated when the light from the display panel 210 irradiates the finger. For the reflected light component RV, the brightness of the fingerprint peak is greater than the brightness of the fingerprint valley.

[0068] The reflected light component RV is a sensing target.

[0069] Fingerprint image B = RV + (-RV2) Formula 2

[0070] The transmitted light component -RV2 in Formula 2 is generated by the strong ambient light that penetrates the finger. For the transmitted light component -RV2, the brightness of the fingerprint peak is less than the brightness of the fingerprint valley. The image characteristics of the transmitted light component -RV2 are opposite to the image characteristics of the reflected light component RV. In other words, the transmitted light component -RV2 will interfere with (affect) the reflected light component RV. Therefore, strong ambient light can easily cause fingerprint signal drift (abnormality), which in turn causes the subsequent circuit to be unable to analyze the fingerprint signal. The following uses multiple embodiments to illustrate how to reduce the transmitted light component -RV2 generated by ambient light in strong ambient light, thereby avoiding fingerprint signal drift as much as possible.

[0071] In a pure strong ambient light environment (the display panel 210 does not provide a light frame), the fingerprint sensing result (fingerprint image C) of the display panel 210 includes a transmitted light component -RV2, as shown in the following formula 3. Because the display panel 210 does not provide a light frame to illuminate the finger, the finger does not reflect light (or the reflected light is extremely weak).

[0072] Fingerprint image C = (-RV2) Formula 3

[0073] This embodiment will illustrate the method of "capturing multiple fingerprint images at different brightnesses (or different ambient light brightnesses) in different frames, and then using these fingerprint images to reduce the negative impact of the transmitted light component -RV2". For example, the processor 230 can subtract the fingerprint image C (the frame displayed by the display panel 210 is low brightness, or the brightness of the frame is 0) from the fingerprint image B (the frame displayed by the display panel 210 is high brightness) to generate a processed fingerprint image, as shown in the following formula 4. Therefore, the transmitted light component -RV2 of the processed fingerprint image can be effectively removed.

[0074] Processed fingerprint image = fingerprint image B - fingerprint image C

[0075] =RV+(-RV2)-(-RV2)=RV Formula 4

[0076] For another example, the processor 230 may subtract the fingerprint image C (the frame displayed by the display panel 210 is low brightness, or the brightness of the frame is 0) from the fingerprint image A (the frame displayed by the display panel 210 is high brightness) to generate a processed fingerprint image, as shown in the following formula 5. Therefore, the brightness difference between the peak and the valley in the reflected light component RV can be gained.

[0077] Processed fingerprint image = fingerprint image A - fingerprint image C

[0078] =RV-(-RV2) Formula 5

[0079] In order to perform the above calculations, the fingerprint sensing driving device 221 may capture fingerprint images multiple times under different light frame brightness (or different ambient light brightness), and then the processor 230 may perform data frame subtraction on these fingerprint images. Figure 6 It is a schematic diagram of capturing two fingerprint images Frame1 and Frame2 by the fingerprint sensing driving device 221 under different light frame brightness conditions according to an embodiment of the present invention. Figure 6 The horizontal axis shown represents time. Figure 6 The RST shown represents a fingerprint frame reset operation. Figure 6 The SIG shown represents a fingerprint frame reading operation. Figure 6 Texp shown here represents the exposure time of each scanning line.

[0080] Based on the reset scan timing, a fingerprint frame reset operation RST can be performed in the touch area of ​​the display panel 210. For the same scan line, the period from the fingerprint frame reset operation RST to the fingerprint frame reading operation SIG is the exposure time Texp. After the exposure time Texp ends, based on the read scan timing, the fingerprint sensing driving device 221 can perform a fingerprint frame reading operation SIG to sense (read) the light sensing result (e.g., fingerprint image Frame1) of the touch area of ​​the display panel 210. For each scan line of the display panel 210, the same scan line can perform the fingerprint frame reset operation RST again after completing the fingerprint frame reading operation SIG, and then after the exposure time Texp ends, the fingerprint frame reading operation SIG can be performed again to sense (read) another light sensing result (e.g., fingerprint image Frame2) of the touch area of ​​the display panel 210.

[0081] The transmitted light intensity and / or reflected light intensity of the finger when capturing the fingerprint image Frame1 may be different from the transmitted light intensity of the finger when capturing the fingerprint image Frame2. For example, the fingerprint sensing driving device 221 may capture the fingerprint image Frame1 of the finger when the frame displayed by the display panel 210 is the first brightness, and then the fingerprint sensing driving device 221 may capture the fingerprint image Frame2 of the finger when the frame displayed by the display panel 210 is the second brightness (lower than the first brightness). Alternatively, in some other embodiments, the fingerprint sensing driving device 221 may capture the fingerprint image Frame1 of the finger when the frame displayed by the display panel 210 is the second brightness, and then the fingerprint sensing driving device 221 may capture the fingerprint image Frame2 of the finger when the frame displayed by the display panel 210 is the first brightness (higher than the second brightness). The first brightness and the second brightness may be determined according to design requirements. For example, the first brightness may be the maximum brightness of the display panel 210 or a preset brightness, and the second brightness may be 0.

[0082] In the process of capturing the fingerprint image, the frame displayed by the display panel 210 can supply light source (incident light) to the user's finger. According to the actual design, the frame displayed by the display panel 210 can be a full-frame image of a single tone, or include any geometric figure as a light spot (speckle). The display driver 222 can adjust the data of the display frame or adjust the brightness of the backlight to adjust the brightness of the frame (such as the light spot) displayed by the display panel 210. For example, the fingerprint sensing driver 221 can capture the fingerprint image Frame1 of the finger when the light spot brightness is "bright", and then the fingerprint sensing driver 221 can capture the fingerprint image Frame2 of the finger when the light spot brightness is "dark".

[0083] Figure 7 FIG. 1 is a diagram showing a relationship curve between the brightness of ambient light and the sensing result of the fingerprint sensing driving device 221 according to an embodiment of the present invention. Figure 7 The horizontal axis represents the brightness (intensity) Lamb of the ambient light, or the brightness of the transmitted light component -RV2 generated by the ambient light penetrating the finger. Figure 7 The vertical axis in the figure represents the sensing result FI of the fingerprint sensing driving device 221. In strong ambient light, two different fingerprint images Frame1 and Frame2 are obtained by adjusting the brightness of the frame (e.g., light spot) displayed by the display panel 210. The fingerprint image Frame1 captured in strong ambient light can refer to the relevant description of the fingerprint image B in formula 2, and the fingerprint image Frame2 captured in strong ambient light can refer to the relevant description of the fingerprint image C in formula 3. Figure 7 The graph shows a relationship curve L1 of the fingerprint image Frame1 captured when the light spot brightness is “bright”, and a relationship curve L2 of the fingerprint image Frame2 captured when the light spot brightness is “dark”.

[0084] After obtaining fingerprint image Frame1 and fingerprint image Frame2, processor 230 can subtract fingerprint image Frame2 from fingerprint image Frame1 to generate a processed fingerprint image to reduce the negative impact of ambient light on the processed fingerprint image. Optical fingerprint sensing device 200 can use the processed fingerprint image to perform fingerprint recognition.

[0085] When a finger touches the display panel 210, the display panel 210 can display a frame (such as a light spot) as a light source for capturing a fingerprint image. In strong ambient light, due to the limited intensity of the light spot, it may not be possible to make the reflected light component RV greater than the transmitted light component -RV2. If turning off the light spot is still not enough, the shape of the light spot can be changed to increase the intensity of the incident light.

[0086] For example, in some embodiments, the fingerprint sensing driver 221 may perform optical fingerprint sensing on the finger through the display panel 210 to obtain a fingerprint image Frame1. The fingerprint sensing driver 221 may transmit the fingerprint image Frame1 back to the processor 230. The processor 230 may perform image analysis on the fingerprint image Frame1 to identify a plurality of feature points in the fingerprint image Frame1. According to the number of feature points or the clarity of the fingerprint image Frame1, the processor 230 may adjust the display parameters of the image frame, such as adjusting the shape, brightness, color or other display parameters of the light spot of the image frame, or even turning off the light spot (not adding the light spot pattern to the image frame). The adjusted image frame will be displayed again on the display panel 210. Based on the adjusted image frame, the fingerprint sensing driver 221 may perform optical fingerprint sensing on the finger through the display panel 210 again to obtain another fingerprint image Frame2. The processor 230 may obtain the fingerprint image Frame2, and perform image operations on the fingerprint image Frame1 and the fingerprint image Frame1 to generate a processed fingerprint image. The processor 230 obtains a processed fingerprint image that eliminates the influence of ambient light according to the fingerprint image Frame 1 and the fingerprint image Frame 1. The processor 230 can use the processed fingerprint image to perform fingerprint recognition.

[0087] In summary, the different frames displayed by the display panel 210 include a first frame with a first light spot and a second frame with a second light spot. Corresponding to the first frame and the second frame, the different fingerprint images captured by the fingerprint sensing driving device 221 include a first fingerprint image and a second fingerprint image. In other words, the fingerprint sensing driving device 221 can drive the display panel 210 to capture the first fingerprint image of the finger when the first light spot is a first brightness, and the fingerprint sensing driving device 221 can drive the display panel 210 to capture the second fingerprint image of the finger when the second light spot is a second brightness (lower than the first brightness). For example (but not limited to this), the second brightness can be 0. The processor 230 can subtract the first fingerprint image from the second fingerprint image to generate a processed fingerprint image to reduce the transmitted light component of the processed fingerprint image.

[0088] Figure 8 8 is a schematic diagram illustrating a frame displayed by the display panel 210 according to an embodiment of the present invention. When the finger 810 touches the display panel 210, the display panel 210 may display a circular light spot 820 in the touch area, such as Figure 8 The annular light spot 820 surrounds the touch area of ​​the finger 810, that is, the fingerprint sensing area is located inside the annular light spot 820. In the process of capturing the fingerprint image, the annular light spot 820 displayed by the display panel 210 can supply light source (incident light) to the user's finger 810. In the strong ambient light 830, Figure 8As shown, when the finger 810 contacts the touch area of ​​the display panel 210, the annular light spot 820 can inject light into the finger 810 from the side of the finger 810. The finger 810 itself can serve as a light guide path, so that the light of the annular light spot 820 can be guided to the touch area (or fingerprint sensing area). Therefore, the light of the annular light spot 820 can enhance the transmitted light component -RV2 (at this time, the transmitted light component -RV2 is contributed by the strong ambient light 830 and the annular light spot 820).

[0089] In other words, Figure 8 In the illustrated embodiment, the frame displayed by the display panel 210 includes a first area (e.g., the center area of ​​the annular light spot 820) and a second area (e.g., the outer annular area of ​​the annular light spot 820, i.e., the first area). Any of the fingerprint images captured by the fingerprint sensing drive device 221 includes: the reflected light component and the first transmitted light component contributed by the first area and the second area of ​​one of the different frames displayed by the display panel 210, and the second transmitted light component contributed by the ambient light. The different frames displayed by the display panel 210 are used to generate, in each of the different fingerprint images, different intensities of the reflected light component and different intensities of the first transmitted light component.

[0090] For example, in Figure 8 In the illustrated embodiment, different frames displayed by the display panel 210 include a first frame having a first light spot and a second frame having a second light spot. Corresponding to the first frame and the second frame, different fingerprint images captured by the fingerprint sensing driving device 221 include a first fingerprint image and a second fingerprint image. The first light spot and the second light spot may be annular light spots 820 with different brightness (or colors). When the first area of ​​the first light spot (e.g., the central area of ​​the annular light spot 820) is the first brightness and the second area of ​​the first light spot (e.g., the annular light spot 820, i.e., the outer annular area of ​​the first area) is the second brightness, the fingerprint sensing driving device 221 drives the display panel 210 to capture the first fingerprint image of the finger. When the first area of ​​the second light spot (e.g., the central area of ​​the annular light spot 820) is the third brightness (lower than the first brightness) and the second area of ​​the second light spot (e.g., the annular light spot 820, i.e., the outer annular area of ​​the first area) is the fourth brightness (higher than the second brightness), the fingerprint sensing driving device 221 drives the display panel 210 to capture the second fingerprint image of the finger. For example (but not limited to this), the third brightness may be 0. The processor 230 may subtract the first fingerprint image from the second fingerprint image to generate a processed fingerprint image, so as to reduce the transmitted light component of the processed fingerprint image.

[0091] In summary, the fingerprint sensing driver 221 described in the above embodiments can capture multiple different fingerprint images of the same finger under different transmitted light intensities and / or different reflected light intensities. The processor 230 can process these different fingerprint images provided by the fingerprint sensing driver 221 to generate a processed fingerprint image to reduce the negative impact of ambient light on fingerprint sensing. Therefore, in strong ambient light, the processor 230 can correctly perform fingerprint recognition.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A driving device, characterized in that: The driving device comprises: A display driving device, coupled to the display panel, for driving the display panel to display different frames with different brightness, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities; and A fingerprint sensing driving device is coupled to the display panel to drive the display panel to perform a fingerprint capture operation to capture a plurality of different fingerprint images of the finger under at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are subtracted to generate a processed fingerprint image.

2. The driving device according to claim 1, characterized in that The different fingerprint images are processed to reduce the negative impact of ambient light on the processed fingerprint images.

3. The driving device according to claim 1, characterized in that: The fingerprint sensing driving device transmits the different fingerprint images to a processor, and the processor processes the different fingerprint images to generate the processed fingerprint image.

4. The driving device according to claim 3, characterized in that: The display driving device is controlled by the processor to generate the different frames.

5. The driving device according to claim 1, characterized in that: The different frames have at least one feature including shape, area, global brightness, local brightness, and quantity to generate at least one of the different transmitted light intensities and the different reflected light intensities.

6. The driving device according to claim 1, characterized in that Any one of the different fingerprint images includes: a reflected light component contributed by the different frames and a transmitted light component contributed by ambient light.

7. The driving device according to claim 6, characterized in that The different frames are used to generate different intensities of the reflected light components of the different fingerprint images.

8. The driving device according to claim 1, characterized in that Any one of the different fingerprint images includes: a reflected light component contributed by a first area of ​​one of the different frames, a first transmitted light component contributed by a second area of ​​one of the different frames, and a second transmitted light component contributed by ambient light.

9. The driving device according to claim 8, characterized in that The different frames are used to generate different intensities of the reflected light components of the different fingerprint images and different intensities of the first transmitted light components of the different fingerprint images.

10. The driving device according to claim 8, characterized in that The first area is a central area of ​​the different frames, and the second area is a peripheral annular area of ​​the different frames.

11. The driving device according to claim 6, characterized in that The different frames include a first frame having a first light spot and a second frame having a second light spot, the different fingerprint images include a first fingerprint image and a second fingerprint image, the fingerprint sensing driving device drives the display panel to capture the first fingerprint image of the finger when the first light spot is a first brightness, and the fingerprint sensing driving device drives the display panel to capture the second fingerprint image of the finger when the second light spot is a second brightness lower than the first brightness.

12. The driving device according to claim 11, characterized in that The first fingerprint image is subtracted from the second fingerprint image to generate the processed fingerprint image so as to reduce the transmitted light component of the processed fingerprint image.

13. The driving device according to claim 11, characterized in that The second brightness is 0.

14. The driving device according to claim 1, characterized in that The different frames include a first frame having a first light spot and a second frame having a second light spot, the different fingerprint images include a first fingerprint image and a second fingerprint image, the fingerprint sensing driving device drives the display panel to capture the first fingerprint image of the finger when the first area of ​​the first light spot is a first brightness and the second area of ​​the first light spot is a second brightness, and the fingerprint sensing driving device drives the display panel to capture the second fingerprint image of the finger when the first area of ​​the second light spot is a third brightness lower than the first brightness and the second area of ​​the second light spot is a fourth brightness higher than the second brightness.

15. The driving device according to claim 14, characterized in that The first fingerprint image is subtracted from the second fingerprint image to generate the processed fingerprint image.

16. The driving device according to claim 14, characterized in that The third brightness is 0.

17. An optical fingerprint sensing device, characterized in that: The optical fingerprint sensing device comprises: A display panel, for performing a fingerprint capture operation on a finger when the finger contacts the display panel; and Drive equipment, including: A display driving device, coupled to the display panel, for driving the display panel to display different frames with different brightness, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities; and A fingerprint sensing driving device is coupled to the display panel to drive the display panel to perform the fingerprint capture operation to capture multiple different fingerprint images of the finger under at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are subtracted to generate a processed fingerprint image.

18. A method for operating a driving device, wherein the driving device is suitable for driving a display panel, characterized in that: The operation method comprises: When a finger contacts the display panel, driving the display panel to display different frames, wherein the different frames are used to generate at least one of different transmitted light intensities and different reflected light intensities; and The display panel is driven to perform a fingerprint capture operation to capture a plurality of different fingerprint images of the finger under the conditions of at least one of the different transmitted light intensities and the different reflected light intensities, wherein the different fingerprint images are subtracted to generate a processed fingerprint image.

19. The operating method according to claim 18, characterized in that: The operation method further includes: The different fingerprint images are processed to reduce the negative impact of ambient light on the processed fingerprint images.

20. The operating method according to claim 18, characterized in that: The operation method further includes: transmitting the different fingerprint images to a processor; and The different fingerprint images are processed by the processor to generate the processed fingerprint image.

21. The operating method according to claim 20, characterized in that: The operation method further includes: The processor controls a display driving device of the driving apparatus to generate the different frames.

22. The operating method according to claim 18, characterized in that: The different frames have at least one feature including shape, area, global brightness, local brightness, and quantity to generate at least one of the different transmitted light intensities and the different reflected light intensities.

23. The operating method according to claim 18, characterized in that: Any one of the different fingerprint images includes: a reflected light component contributed by the different frames and a transmitted light component contributed by ambient light.

24. The operating method according to claim 23, characterized in that: The different frames are used to generate different intensities of the reflected light components of the different fingerprint images.

25. The operating method according to claim 18, characterized in that: Any one of the different fingerprint images includes: a reflected light component contributed by a first area of ​​one of the different frames, a first transmitted light component contributed by a second area of ​​one of the different frames, and a second transmitted light component contributed by ambient light.

26. The operating method according to claim 25, characterized in that: The different frames are used to generate different intensities of the reflected light components of the different fingerprint images and different intensities of the first transmitted light components of the different fingerprint images.

27. The operating method according to claim 25, characterized in that: The first area is a central area of ​​the different frames, and the second area is a peripheral annular area of ​​the different frames.

28. The operating method according to claim 23, characterized in that: The different frames include a first frame having a first light spot and a second frame having a second light spot, the different fingerprint images include a first fingerprint image and a second fingerprint image, and the operation method further includes: The fingerprint sensing driving device drives the display panel to capture the first fingerprint image of the finger when the first light spot is at a first brightness; and When the second light spot has a second brightness lower than the first brightness, the display panel is driven to capture the second fingerprint image of the finger.

29. The operating method according to claim 28, characterized in that: The operation method further includes: The processed fingerprint image is generated by subtracting the first fingerprint image from the second fingerprint image, so as to reduce the transmitted light component of the processed fingerprint image.

30. The operating method according to claim 28, characterized in that: The second brightness is 0.

31. The operating method according to claim 18, characterized in that: The different frames include a first frame having a first light spot and a second frame having a second light spot, the different fingerprint images include a first fingerprint image and a second fingerprint image, and the operation method further includes: When the first area of ​​the first light spot is at a first brightness and the second area of ​​the first light spot is at a second brightness, driving the display panel to capture the first fingerprint image of the finger; When the first area of ​​the second light spot has a third brightness lower than the first brightness and the second area of ​​the second light spot has a fourth brightness higher than the second brightness, the display panel is driven to capture the second fingerprint image of the finger.

32. The operating method according to claim 31, characterized in that: The operation method further includes: The processed fingerprint image is generated by subtracting the first fingerprint image from the second fingerprint image.

33. The operating method according to claim 31, characterized in that: The third brightness is 0.

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