Electronic circuit with display driving, touch sensing and fingerprint sensing functions

Abstract

The invention provides an electronic circuit. The electronic circuit comprises a touch sensing circuit, a fingerprint sensing circuit and a display driving circuit. The touch sensing circuit is configured to sense a touch by a finger and determine a first area on the display panel corresponding to the touch. The fingerprint sensing circuit is configured to sense a fingerprint image of a finger corresponding to a first region of the display panel. The display driving circuit is configured to drive pixels of the first region at respective second gray levels and pixels of a second region other than the first region at respective third gray levels. Wherein the display driving circuit processes the corresponding fourth gray level to obtain the corresponding third gray level, and the display driving circuit generates gamma voltage corresponding to the corresponding second gray level and the corresponding third gray level according to the same gamma curve.

Description

[0001] This patent application is a divisional application of the following invention patent applications:

[0002] Application number: 202010788866.9

[0003] Application date: August 7, 2020

[0004] Invention Title: Electronic circuit with display driving, touch sensing and fingerprint sensing functions Technical Field

[0005] The present invention relates to an electronic circuit and a driving method, and more particularly, to an electronic circuit suitable for driving a display panel including a touch sensor and a fingerprint sensor and a method for driving the display panel. Background Art

[0006] In recent years, the demand for fingerprint sensing has gradually increased. In order to reduce the volume of electronic devices, the fingerprint sensing area may overlap with the display area of ​​the electronic device. For example, the under-display fingerprint identification technique is to embed the fingerprint sensor into the display panel, and the fingerprint sensor can sense or capture the fingerprint image through the display panel. When a touch event such as fingerprint identification occurs, the touch sensing circuit can report it to the application processor of the electronic device through a specified interface. Next, the application processor further controls the display driver circuit to drive the display panel to display an image for fingerprint sensing. The display driver circuit can control the backlight controller to adjust the backlight of the display panel based on the instructions of the application processor. The entire backlight can be turned on to have the highest brightness. However, the high brightness of the display panel may make the user feel uncomfortable.

[0007] On the other hand, the application processor further controls the fingerprint sensing circuit to perform the fingerprint sensing operation. The fingerprint sensing circuit transmits the sensing information to the application processor for fingerprint recognition after the fingerprint sensing operation, and then the application processor completes the fingerprint recognition according to the sensing information. However, the touch sensing circuit needs to report the touch event to the application processor, and the display driving circuit and the fingerprint sensing circuit that operate to display images and sense fingerprints are based on the instructions of the application processor. Therefore, it may take more time to perform fingerprint sensing and recognition. Summary of the invention

[0008] The present invention relates to an electronic circuit capable of providing an efficient fingerprint sensing and identification method and providing a user with a good user experience, and also provides a method for driving a display panel by using the electronic circuit.

[0009] An embodiment of the present invention provides an electronic circuit suitable for driving a display panel including a touch sensor and a fingerprint sensor. The electronic circuit includes a touch sensing circuit, a fingerprint sensing circuit and a display driving circuit. The touch sensing circuit is configured to sense the touch of a finger and determine a first area on the display panel corresponding to the touch. The fingerprint sensing circuit is configured to sense a fingerprint image corresponding to the finger and the first area of ​​the display panel. The display driving circuit is configured to drive pixels in the first area with a corresponding second grayscale and drive pixels in a second area outside the first area with a corresponding third grayscale. The display driving circuit processes the corresponding fourth grayscale to obtain a corresponding third grayscale, and the display driving circuit generates a gamma voltage corresponding to the corresponding second grayscale and the corresponding third grayscale according to the same gamma curve.

[0010] An embodiment of the present invention provides an electronic circuit suitable for driving a display panel including a touch sensor and a fingerprint sensor. The electronic circuit cooperates with the display panel and the application processor to perform a fingerprint recognition operation. The electronic circuit includes a touch sensing circuit, a fingerprint sensing circuit, a display driving circuit, a first interface circuit and a second interface circuit. The touch sensing circuit is configured to sense the touch of a finger and determine a first area corresponding to the touch on the display panel. The display driving circuit is configured to drive the pixels of the first area of ​​the display panel with a display pattern indicating a fingerprint input area. The fingerprint sensing circuit is configured to sense the fingerprint image corresponding to the finger and the first area of ​​the display panel. When the touch is recognized as valid, the touch sensing circuit controls the fingerprint sensing circuit via the first interface circuit to start the fingerprint scan of the first area and sense the fingerprint image of the finger from the first area. The touch sensing circuit controls the display driving circuit via the second interface circuit to drive the pixels of the first area of ​​the display panel with the display pattern indicating the fingerprint input area. The fingerprint sensing circuit transmits the fingerprint image to the application processor for the application processor to perform the fingerprint recognition operation. The display driving circuit drives the pixels of the first area with a corresponding second grayscale. The touch sensing circuit controls the display driving circuit via the second interface circuit to drive the pixels of the second area outside the first area with a corresponding third grayscale. The display driving circuit processes the corresponding fourth gray level to obtain the corresponding third gray level, and the display driving circuit generates a gamma voltage corresponding to the corresponding second gray level and the corresponding third gray level according to the same gamma curve.

[0011] An embodiment of the present invention provides a method for driving a display panel including a touch sensor and a fingerprint sensor, comprising: sensing a touch of a finger to determine a first area on the display panel corresponding to the touch; sensing a fingerprint image of the finger corresponding to the first area of ​​the display panel; driving pixels in the first area with a corresponding second gray level, and driving pixels in a second area outside the first area with a corresponding third gray level; processing a corresponding fourth gray level to obtain a corresponding third gray level; and generating a gamma voltage corresponding to the corresponding second gray level and the corresponding third gray level according to the same gamma curve.

[0012] In order to make the above content easier to understand, several embodiments are described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention.

[0014] Figure 1 is a schematic block diagram showing an electronic device according to an embodiment of the present invention.

[0015] Figure 2 It is shown Figure 1 A schematic diagram of the display panel is shown.

[0016] Figure 3 It is shown Figure 1 Schematic block diagram of the electronic circuit shown.

[0017] Figure 4 is a schematic block diagram showing an electronic device according to another embodiment of the present invention.

[0018] Figure 5 FIG. 1 shows an example of a first operation mode according to an embodiment of the present invention. Figure 4 Electronic device shown.

[0019] Figure 6 FIG. 1 shows an example of an embodiment of the present invention operating in a second operating mode. Figure 4 Electronic device shown.

[0020] Figure 7 is a flow chart showing steps in a fingerprint recognition method according to an embodiment of the present invention.

[0021] Figure 8 is a schematic block diagram showing an electronic device according to another embodiment of the present invention.

[0022] Fig. 9 A voltage conversion operation according to an embodiment of the present invention is shown.

[0023] Fig.10 A data processing operation according to an embodiment of the present invention is shown.

[0024] Fig.11 is a flow chart illustrating steps in a method for driving a display panel according to an embodiment of the present invention.

[0025] Reference numerals list

[0026] 100, 200, 400: Electronic devices

[0027] 110: Electronic circuits

[0028] 112: Display driver circuit

[0029] 114: Touch sensing circuit

[0030] 116: Fingerprint sensing circuit

[0031] 120: Display panel

[0032] 121: Timing controller

[0033] 122: Display pixels

[0034] 123: Other controllers or processors

[0035] 124: Touch sensor

[0036] 125: Display driver

[0037] 126: Fingerprint sensor

[0038] 130: Control circuit

[0039] 141: Touch Controller

[0040] 143, 163: Analog front-end circuit

[0041] 161: Digital Circuits

[0042] 165: Gate Driver

[0043] 230: Application Processor

[0044] 232: Trust Zone

[0045] 240: Backlight module

[0046] 310: First Area

[0047] 320: Second Area

[0048] 330: Part of the area

[0049] 410: The first semiconductor chip

[0050] 420: Second semiconductor chip

[0051] DATA1, DATA2: Data processing curve

[0052] FSL: Fingerprint Sensing Line

[0053] GDL: Display scan lines

[0054] GMA1: First gamma curve

[0055] GMA2: Second gamma curve

[0056] GSL: Fingerprint Scan Line

[0057] IF1: First interface circuit

[0058] IF2: Second interface circuit

[0059] S1: Touch sensing signal

[0060] S2, S4: driving signal

[0061] S3: Fingerprint sensing signal

[0062] S6: Pulse width modulation signal

[0063] S100, S110, S120, S130, S200, S210, S220, S230: Steps

[0064] SDL: Display data lines

[0065] TSL: Touch Sense Line DETAILED DESCRIPTION

[0066] The following embodiments are provided to elaborate the present invention in detail, but the present invention is not limited to the provided embodiments, and the provided embodiments can be appropriately combined. The terms "coupled / coupled" or "connected / connected" used in the specification (including claims) of this application may refer to any direct or indirect means of connection. For example, "a first device is coupled to a second device" should be interpreted as "a first device is directly connected to a second device" or "a first device is indirectly connected to a second device via other devices or connection means". The term "signal" may refer to current, voltage, charge, temperature, data, electromagnetic waves or any one or more signals. In addition, the term "and / or" may refer to "at least one of..." For example, "a first signal and / or a second signal" should be interpreted as "at least one of a first signal and a second signal".

[0067] Figure 1 is a schematic block diagram showing an electronic device according to an embodiment of the present invention. Figure 1The electronic device 100 of this embodiment includes an electronic circuit 110 and a display panel 120. The display panel 120 includes a touch sensor and a fingerprint sensor. The electronic circuit 110 can be configured to be coupled to the display panel 120. The electronic circuit 110 is suitable for driving the display panel 120.

[0068] In this embodiment, the electronic device 100 may be an electronic device with a display function, a touch sensing function, and a fingerprint sensing function. In one embodiment, the electronic device 100 may be, but not limited to, a smart phone, a non-smart phone, a wearable electronic device, a tablet computer, a personal digital assistant, a notebook computer, and other portable electronic devices that can operate independently and have a display function, a touch sensing function, and a fingerprint sensing function. In one embodiment, the electronic device 100 may be, but not limited to, a portable or non-portable electronic device in a vehicle intelligent system. In one embodiment, the electronic device 100 may be, but not limited to, a smart home appliance, such as a television, a computer, a refrigerator, a washing machine, a telephone, an induction cooker, a table lamp, etc.

[0069] Figure 2 It is shown Figure 1 Schematic diagram of the display panel shown. Figure 2 , the display panel 120 of this embodiment includes multiple display pixels 122, multiple touch sensors 124 and multiple fingerprint sensors 126. The electronic circuit 110 drives and controls the display panel 120 to perform display operations, touch sensing operations and fingerprint sensing operations. Specifically, the electronic circuit 110 drives and controls the display pixels 122 to display images via the display scan lines GDL and the display data lines SDL. The electronic circuit 110 also drives and controls the touch sensors 124 to sense touch events of the display panel 120 via the touch scan lines and the touch sensing lines TSL. In one embodiment, the touch sensor 124 may be a touch sensing electrode in the touch sensing stage, and the touch sensor 124 may be a common electrode in the display stage. In this embodiment, as Figure 2 As shown, the touch sensor 124 of the display panel 120 may be an in-cell touch sensor. For the in-cell touch sensor, the display panel 120 does not have a touch scan line, and the touch drive signal may be directly transmitted to the touch sensor 124 via the touch sensing line TSL. For other types of touch sensors, the display panel 120 may have a touch scan line for transmitting the touch drive signal. The electronic circuit 110 also drives and controls the fingerprint sensor 126 to sense the fingerprint image on the display panel 120 via the fingerprint scan line GSL and the fingerprint sensing line FSL.

[0070] In one embodiment, the display panel 120 may be an in-pixel fingerprint, touch and display panel with a fingerprint sensor and a touch sensor embedded therein, but the present invention is not limited thereto. In one embodiment, the electronic circuit 110 may drive and control the electronic device 100 to perform an in-display fingerprint recognition operation, i.e., a fingerprint identification operation. In one embodiment, the fingerprint sensor 126 may be an optical fingerprint sensor.

[0071] Figure 3 It is shown Figure 1 Schematic block diagram of the electronic circuit shown. Figure 2 and Figure 3 , the electronic circuit 110 may include a display driving circuit 112, a fingerprint sensing circuit 116, and a touch sensing circuit 114. The display driving circuit 112 is configured to drive and control the display pixel 122 to display an image via the display scan line GDL and the display data line SDL. The display driving circuit 112 generates a display driving signal to drive the display data line SDL of the display panel 120. The display driving circuit 112 may include a timing controller 121, a display driver, and other functional circuits for display operation. The display driving circuit 112 may also include other controllers or processors 123 for other control activities of the display operation. The touch sensing circuit 114 is configured to drive and control the touch sensor 124 to sense a touch event of the display panel 120 via the touch sensing line TSL. The touch sensing circuit 114 may include a touch controller 141, an analog front end (AFE) circuit, an analog-to-digital converter (ADC) circuit, and other functional circuits for touch sensing operations. The fingerprint sensing circuit 116 is configured to drive and control the fingerprint sensor 126 to sense the fingerprint on the display panel 120 via the fingerprint scanning line GSL and the fingerprint sensing line FSL. The fingerprint sensing circuit 116 receives a fingerprint sensing signal corresponding to a fingerprint image from the fingerprint sensor 126, and may also process the fingerprint sensing signal to obtain a fingerprint image. The fingerprint sensing circuit 116 may include a digital circuit 161, an AFE circuit, an ADC circuit, and other functional circuits for fingerprint sensing operations.

[0072] In one embodiment, when the electronic circuit 110 is implemented as a single-chip integrated circuit that can drive and control the display panel 120 to perform display operations, touch sensing operations, and fingerprint sensing operations, the electronic circuit 110 may include a control circuit 130, and the control circuit 130 is, for example, a circuit based on a microcontroller core to perform all control activities of the display operation, touch sensing operation, and fingerprint sensing operation. The control circuit 130 may include at least one of the timing controller 121, the touch controller 141, the digital circuit 161, and other controllers or processors 123 of the display driving circuit 112.

[0073] The display driving circuit 112, the touch sensing circuit 114 and the fingerprint sensing circuit 116 communicate with each other via a signal transmission interface (e.g., a Mobile Industry Processor Interface (MIPI), an Inter-Integrated Circuit (I2C) interface, a Serial Peripheral Interface (SPI) and / or other similar or suitable interfaces).

[0074] about Figure 3 The hardware structure of the components in the illustrated embodiment, the timing controller 121, the touch controller 141 and the digital circuit 161 may be a processor with computing capabilities. Alternatively, the timing controller 121, the touch controller 141 and the digital circuit 161 may be designed by a hardware description language (HDL) or any other digital circuit design method familiar to a person skilled in the art, and may be a hardware circuit implemented by a field programmable gate array (FPGA), a complex programmable logic device (CPLD) or an application-specific integrated circuit (ASIC). In addition, referring to the common sense in the relevant art, sufficient teachings, suggestions and implementation instructions for the hardware structure of the display driving circuit 112, the touch sensing circuit 114 and the fingerprint sensing circuit 116 may be obtained, and no further description will be given below.

[0075] Figure 4 is a schematic block diagram showing an electronic device according to another embodiment of the present invention. Figure 4, the electronic device 200 of the present embodiment includes an electronic circuit 110, a display panel 120, an application processor 230 and a backlight module 240. The electronic circuit 110 includes a display driving circuit 112, a touch sensing circuit 114, a fingerprint sensing circuit 116, a first interface circuit IF1 and a second interface circuit IF2. The first interface circuit IF1 includes a circuit for transmitting and receiving signals arranged in the touch sensing circuit 114 and / or the fingerprint sensing circuit 116. The second interface circuit IF2 includes a circuit for transmitting and receiving signals arranged in the touch sensing circuit 114 and / or the display driving circuit 112. The touch sensing circuit 114 and the fingerprint sensing circuit 116 communicate with each other via the first interface circuit IF1. The display driving circuit 112 and the touch sensing circuit 114 communicate with each other via the second interface circuit IF2.

[0076] In this embodiment, the electronic circuit 110 cooperates with the display panel 120 and the application processor 230 to perform a fingerprint recognition operation. The electronic circuit 110 outputs a fingerprint image to the trust zone 232 of the application processor 230 to perform a fingerprint recognition operation, i.e., a fingerprint identification operation. With reference to common knowledge in the relevant art, sufficient teachings, suggestions, and implementation instructions for the fingerprint recognition operation can be obtained, which will not be described in detail below.

[0077] Figure 5 FIG. 1 shows an example of a first operation mode according to an embodiment of the present invention. Figure 4 For example, the first operation mode may operate when the user logs into the electronic device 200 in a power-on state of the electronic device 200 or re-logs into the electronic device 200 from an idle state of the electronic device 200. Figure 4 and Figure 5, the electronic device 200 of the present embodiment may be a smart phone or a similar device having an application processor 230, but the present invention is not limited thereto. In the first operating mode, the display driving circuit 112 drives the pixels on the display panel 120 at a corresponding first grayscale during the first stage. The grayscale used to drive the pixel (i.e., the display pixel 122) represents the intensity (intensity) or brightness (brightness) of the color, and each pixel is driven by a corresponding grayscale to present the intensity or brightness of the color. Before displaying the first area 310 (the first stage), a dark screen is displayed on the entire display panel 120, that is, the corresponding first grayscale makes the display panel 120 present a relatively low brightness. During the first stage, the fingerprint sensing circuit 116 may be idle (idle) and operate in a power saving mode. The touch sensing circuit 114 is configured to sense the touch of a finger and determine the first area 310 on the display panel 120 corresponding to the touch. The touch sensing circuit 114 controls the display driving circuit 112 to drive the pixels of the first area 310 with the corresponding second grayscale and to drive the pixels of the second area 320 outside the first area 310 with the corresponding third grayscale during the second stage later than the first stage via the second interface circuit IF2. In the present embodiment, the corresponding second grayscale is higher than the corresponding first grayscale, and the corresponding third grayscale is lower than the corresponding second grayscale. Therefore, the first area 310 with high brightness is displayed on the display panel 120, and can be used as a fingerprint input area after the first area 310 is displayed (second stage). During the second stage, the fingerprint sensing circuit 116 operates in normal power mode. The brightness of the backlight in the second stage is greater than the brightness in the first stage. The first area 310 can be displayed as a white area or an area with a predetermined color. A dark screen can still be displayed on the second area 320, in which case the corresponding third grayscale is substantially the same as the corresponding first grayscale. Therefore, the first area 310 (fingerprint input area) can be highlighted by high brightness, and the second area 320 is presented with lower brightness, such as maintaining a dark screen during the first stage, to avoid discomfort to the user's eyes.

[0078] The touch sensing circuit 114 includes a touch controller 141 and an AFE circuit 143. The AFE circuit 143 receives a touch sensing signal S1 from the display panel 120, and processes the touch sensing signal S1 and transmits it to the touch controller 141. The touch controller 141 determines a first area 310 corresponding to the touch on the display panel 120 according to the touch sensing signal S1. The touch controller 141 can obtain coordinate information and size information of the touch to determine the first area 310 accordingly. The size and shape of the first area may be predetermined, or may depend on the size and shape of the detected touch area. In one embodiment, the first area is determined with a suitable size and shape so that it can be completely covered by the finger when scanning the fingerprint. In one embodiment, the AFE circuit 143 may Figure 2 The touch sensor 124 is shown transmitting a touch driving signal, and receiving a touch sensing signal S1 from the touch sensor 124. The touch sensing signal S1 is transmitted to the touch controller 141 for determining whether a touch occurs.

[0079] The touch sensing circuit 114 controls the display driving circuit 112 via the second interface circuit IF2. The display driving circuit 112 is configured to drive the pixels of the first area 310 of the display panel 120 with a display pattern indicating a fingerprint input area. The display driving circuit 112 includes a timing controller 121 and a display driver 125. The display driver 125 drives the display panel 120 to display an image via a drive signal S2. In the present embodiment, the display driver 125 drives the display panel 120 to display a circular area (first area 310) to indicate the fingerprint input area, but the present invention is not limited to this. In other embodiments, the display pattern may be displayed in any form suitable for fingerprint input. With reference to common sense in the relevant art, sufficient teachings, suggestions and implementation instructions for the method for controlling and driving the display panel 120 can be obtained, which will not be repeated below.

[0080] In the present embodiment, the touch sensing circuit 114 controls the display driving circuit 112 via the second interface circuit IF2 to adjust the backlight module 240 of the electronic device 200 through a pulse width modulation (PWM) signal S6. For example, the touch controller 141 may inform the display driving circuit 112, and then the backlight controller of the display driving circuit 112 outputs the PWM signal S6 to adjust the brightness of the backlight by adjusting the duty cycle of the PWM signal S6. In addition, the frequency of the PWM signal may be adjusted. By adjusting the frequency of the PWM signal S6, an optimized frequency may be provided to the backlight module 240. Therefore, a first area 310 with high brightness is displayed on the display panel 120 to be used as a fingerprint input area. The first area 310 may be displayed as a white area or an area with a predetermined color. A dark screen may still be displayed on the second area 320 outside the first area 310.

[0081] On the other hand, the touch controller 141 determines whether the touch is valid. When the detected touch area is greater than a predetermined threshold area, the touch controller 141 determines the touch as a valid touch. That is, if the detected touch area is greater than a predetermined threshold area, the touch is identified as valid. When a valid touch occurs, the touch controller 141 controls the fingerprint sensing circuit 116 via the first interface circuit IF1 to start a fingerprint scan of the first area 310. In other embodiments, the touch controller 141 may determine whether the touch is valid based on the shape, intensity and / or touch time of the touch. For example, a double click or a long touch may be determined as a valid touch.

[0082] Compared with the global display area of ​​the display panel 120, the first area 310 is a local display area of ​​the display panel 120 for fingerprint input, so that the speed of fingerprint scanning can become faster. The fingerprint sensing circuit 116 is configured to sense a fingerprint image corresponding to the finger and the first area 310 of the display panel 120. The fingerprint sensing circuit 116 includes a digital circuit 161, an AFE circuit 163 and a gate driver 165. The gate driver 165 drives the fingerprint sensor 126 corresponding to the first area 310 via a driving signal S4 to perform a fingerprint sensing operation, and thus the fingerprint sensor 126 corresponding to the first area 310 transmits the fingerprint sensing signal S3 to the AFE circuit 163. The AFE circuit 163 receives the fingerprint sensing signal S3 from the display panel 120, and processes the fingerprint sensing signal S3 and transmits it to the digital circuit 161. Next, the digital circuit 161 generates a fingerprint image and transmits it via an interface between the application processor 230 and the electronic circuit 110 (for example, Figure 4 The fingerprint image is transmitted to the application processor 230 via the SPI in the fingerprint recognition operation.

[0083] In the present embodiment, the fingerprint sensing circuit 116 can operate in a normal power mode or a power saving mode. During the second stage, the touch controller 141 wakes up the fingerprint sensing circuit 116 from the power saving mode to the normal power mode, and outputs the position and size information of the first area 310 to the fingerprint sensing circuit 116 via the first interface circuit IF1. The fingerprint sensing circuit 116 starts the fingerprint scanning of the first area 310. In one embodiment, when the fingerprint scanning is performed, the gate driver 165 drives the fingerprint scanning line GSL corresponding to the first area 310, and the AFE circuit 163 receives the fingerprint sensing signal S3 from the fingerprint sensing line FSL corresponding to the first area 310. In the embodiment, the fingerprint scanning is performed only on the first area 310 determined by the touch controller 141.

[0084] In the present embodiment, the first interface circuit IF1 is located between the touch sensing circuit 114 and the fingerprint sensing circuit 116, and the second interface circuit IF2 is located between the touch sensing circuit 114 and the display driving circuit 112. The touch sensing circuit 114 directly controls the display driving circuit 112 to adjust the backlight and display the fingerprint input area via the second interface circuit IF2 instead of the application processor 230. The touch sensing circuit 114 directly controls the fingerprint sensing circuit 116 to perform fingerprint scanning and sensing operations via the first interface circuit IF1 instead of the application processor 230. The time for performing fingerprint scanning and sensing operations can be shortened.

[0085] about Figure 4 The hardware structure of the components in the illustrated embodiment, the timing controller 121, the touch controller 141 and the digital circuit 161 may be a processor with computing capabilities. Alternatively, the timing controller 121, the touch controller 141 and the digital circuit 161 may be designed by a hardware description language (HDL) or any other digital circuit design method familiar to those skilled in the art, and may be a hardware circuit implemented by a field programmable gate array (FPGA), a complex programmable logic device (CPLD) or an application-specific integrated circuit (ASIC).

[0086] Figure 6 FIG. 1 shows an example of an embodiment of the present invention operating in a second operating mode. Figure 4 The electronic device shown. Figure 4 and Figure 6, the second operating mode of the electronic device 200 is not applied in a standby or idle state. For a certain application (such as mobile payment or bank login), at least one partial area 330 with a higher brightness than the dark screen is displayed in the display panel 120 in the second operating mode, but the present invention is not limited to this. In one embodiment, during the first stage in the second operating mode, a bright screen can be displayed on the entire display panel 120. The brightness of the bright screen is not as high as the brightness of the first area 310 to be displayed during the second stage. During the second stage, the first area 310 with high brightness is displayed on the display panel 120 to be used as a fingerprint input area, and the second area 320 is displayed with a lower brightness. The first area 310 may be displayed as a white area or an area with a predetermined color. During the second stage, the bright screen as described during the first stage can still be displayed on the second area 320.

[0087] The touch sensing circuit 114 controls the fingerprint sensing circuit 116 via the first interface circuit IF1 to start scanning the fingerprint of the first area 310 and sense the fingerprint image of the finger from the first area 310. The fingerprint sensing circuit 116 transmits the fingerprint image to the application processor 230 for the application processor 230 to perform a fingerprint recognition operation. Figure 4 and Figure 5 The operation of the electronic device 200 in the embodiment of the present invention is fully taught, suggested and implemented in the illustrated embodiment, and therefore no further description is provided herein.

[0088] Figure 7 FIG. 1 is a flow chart showing the steps in a fingerprint recognition method according to an embodiment of the present invention. Figures 4 to 7 The fingerprint recognition method of this embodiment is at least suitable for Figure 4 The electronic device 200 shown in the figure is a display panel 120, but the present invention is not limited thereto. Taking the electronic device 200 as an example, in step S100, the touch controller 141 detects a touch event of the display panel 120 to determine the first area 310. The touch event includes fingerprint recognition. In step S110, the touch controller 141 informs the display driving circuit 112 to display the first area 310 with higher brightness and the second area 320 with lower brightness via the second interface circuit IF2. The first area 310 with higher brightness is used as a fingerprint input area. In step S110, the backlight module 240 can increase the brightness of the backlight of the electronic device 200 according to the instruction of the backlight controller. In step S120, the touch controller 141 wakes up the fingerprint sensing circuit 116 via the first interface circuit IF1, and controls the fingerprint sensing circuit 116 to start the fingerprint scanning of the first area 310 and sense the fingerprint image of the finger from the first area 310. In step S130, the application processor 230 receives the fingerprint image from the fingerprint sensing circuit 116 and performs the fingerprint recognition operation in the trust zone 232.

[0089] exist Figures 4 to 6 Other features of the fingerprint recognition method in the embodiment of the present invention are fully taught, suggested and implemented in the illustrated embodiment, and therefore no further description is provided herein.

[0090] Figure 8 is a schematic block diagram showing an electronic device according to another embodiment of the present invention. Figure 4 , the display driving circuit 112 , the touch sensing circuit 114 , and the fingerprint sensing circuit 116 may be formed in a single semiconductor chip capable of driving and controlling the display panel 120 to perform display operations, touch sensing operations, and fingerprint sensing operations. Figure 8 The electronic device 400 shown is similar to Figure 4 The electronic device 200 shown in the figure, and the main difference between these electronic devices is that, for example, the display driving circuit 112 and the touch sensing circuit 114 can be formed in a first semiconductor chip 410 capable of driving and controlling the display panel 120 to perform display operations and touch sensing operations, and the fingerprint sensing circuit 116 can be formed in a second semiconductor chip 420 different from the first semiconductor chip. The second semiconductor chip 420 can be a readout integrated circuit (ROIC) chip. The ROIC is an integrated circuit configured to read a signal from a fingerprint sensor.

[0091] The first semiconductor chip 410 and the second semiconductor chip 420 can communicate with each other via the first interface circuit IF1. Figures 4 to 7 The operation of the electronic device 400 in the embodiments of the present invention is fully taught, suggested and implemented in the illustrated embodiment, and therefore no further description is provided herein.

[0092] Fig. 9 FIG. 2 shows a voltage conversion operation according to an embodiment of the present invention. Figure 4 and Fig. 9 , the display driving circuit 112 includes a first gamma curve GMA1 and a second gamma curve GMA2. The second gamma curve GMA2 may be generated according to the first gamma curve GMA1. The display driving circuit 112 may drive the pixels on the display panel 120 according to one of the first gamma curve GMA1 and the second gamma curve GMA2 during the first stage. In one embodiment, the display driving circuit 112 generates a gamma voltage corresponding to a corresponding first grayscale level according to the first gamma curve GMA1 during the first stage for driving the pixels on the display panel 120.

[0093] Furthermore, during the second phase, the display driving circuit 112 generates a gamma voltage corresponding to the corresponding second gray level according to the first gamma curve GMA1, and the generated gamma voltage is configured to drive the pixels of the first area 310. On the other hand, during the second phase, the display driving circuit 112 generates a gamma voltage corresponding to the corresponding third gray level according to the second gamma curve GMA2, and the generated gamma voltage is configured to drive the pixels of the second area 320. Fig. 9 As shown, for designated pixel data, the absolute value of the gamma voltage generated in the first gamma curve GMA1 is greater than the absolute value of the gamma voltage generated in the second gamma curve GMA2.

[0094] Therefore, the voltage conversion operation is performed so that the gamma voltage for driving the pixels of the second area 320 is converted according to the second gamma curve GMA2 during the second stage. Therefore, during the second stage, when the backlight is adjusted to have a high brightness for displaying the first area 310, a dark screen (or a screen with normal brightness, such as Figure 6 bright screen as shown) to compensate for the high brightness of the backlight.

[0095] Fig.10 The data processing operation according to the embodiment of the present invention is shown. Fig.10 , the display driving circuit 112 may drive the pixels on the display panel 120 to display a dark screen (or a bright screen) at the corresponding first gray level during the first stage. The corresponding first gray level is not modified during the first stage, and a gamma voltage corresponding to the corresponding first gray level may be generated according to the first gamma curve GMA1. Fig.10 , the data processing curve DATA1 is a linear curve, i.e., a straight line. The display driving circuit 112 processes the input data according to the data processing curve DATA1 during the second stage to generate output data (e.g., a corresponding second gray level) to drive the pixels of the first area 310. Since the data processing curve DATA1 is a linear curve, the corresponding second gray level does not change before and after the data processing operation. A gamma voltage corresponding to the corresponding second gray level may be generated according to the first gamma curve GMA1. The generated gamma voltage is configured to drive the pixels of the first area 310 during the second stage.

[0096] On the other hand, the display driving circuit 112 processes the input data (e.g., the corresponding fourth gray level) according to the data processing curve DATA2 during the second stage to generate output data (e.g., the corresponding third gray level) to drive the pixels of the second area 320. After the data processing operation, the corresponding fourth gray level is modified to the corresponding third gray level. For example, according to the data processing curve DATA2, the input gray level 255 is modified to the output gray level 200, and the input gray level 127 is modified to the output gray level 50. A gamma voltage corresponding to the corresponding third gray level may be generated according to the first gamma curve GMA1. The generated gamma voltage is configured to drive the pixels of the second area 320 during the second stage. In the present embodiment, a gamma voltage corresponding to the corresponding second gray level and the corresponding third gray level may be generated according to the same gamma curve (e.g., the first gamma curve GMA1). After the data processing operation, the corresponding gray level is modified, and during the second stage, a dark screen (or a bright screen) may still be displayed on the second area 320 to compensate for the high brightness of the backlight.

[0097] Fig.11 1 is a flow chart showing steps in a method for driving a display panel according to an embodiment of the present invention. Figure 4 , Figure 5 and Fig.11 The method for driving a display panel of this embodiment is at least suitable for Figure 4 The electronic device 200 shown in the figure is not limited thereto. Taking the electronic device 200 as an example, in step S200, the touch sensing circuit 114 senses the touch of the finger to determine the first area 310 on the display panel 120 corresponding to the touch. In step S210, the fingerprint sensing circuit 116 senses the fingerprint image of the finger corresponding to the first area 310 of the display panel 120. In step S220, the display driving circuit 112 drives the pixels on the display panel 120 at the corresponding first gray level during the first stage. In step S230, the display driving circuit 112 drives the pixels of the first area 310 at the corresponding second gray level during the second stage, and drives the pixels of the second area 320 outside the first area 310 at the corresponding third gray level.

[0098] exist Figures 4 to 10 The method for driving a display panel in the embodiments of the present invention is fully taught, suggested and implemented in the illustrated embodiments, and therefore no further description is provided herein.

[0099] In summary, in an embodiment of the present invention, the touch sensing circuit performs a touch sensing operation to determine the fingerprint input area, and controls the fingerprint sensing circuit via the first interface circuit instead of the application processor to start a fingerprint scan of the fingerprint input area. The scanning area is a local area of ​​the entire display panel. In addition, the touch sensing circuit controls the display driving circuit via the second interface circuit instead of the application processor to drive the pixel to indicate the display pattern of the fingerprint input area. Therefore, the fingerprint sensing and identification method is more efficient. The fingerprint input area (ie, the sensing area) may have a higher brightness than the non-sensing area. When the fingerprint input area is displayed, the non-sensing area is driven by a lower voltage to compensate for the high brightness of the backlight, so that the user has a good user experience.

[0100] It will be appreciated by those skilled in the art that various modifications and variations may be made to the disclosed embodiments without departing from the scope or spirit of the invention. In view of the foregoing, the present invention is intended to cover modifications and variations as long as the modifications and variations fall within the scope of the above claims and their equivalents.

Claims

1. An electronic circuit, suitable for driving a display panel including a touch sensor and a fingerprint sensor, the electronic circuit comprising: a touch sensing circuit configured to sense a touch of a finger and determine a first area on the display panel corresponding to the touch; a fingerprint sensing circuit configured to sense a fingerprint image of the finger corresponding to the first area of ​​the display panel; as well as The display driving circuit is configured to drive the pixels of the first area at a corresponding second gray level and drive the pixels of the second area outside the first area at a corresponding third gray level, The display driving circuit processes the corresponding fourth gray level to obtain the corresponding third gray level, and the display driving circuit generates gamma voltages corresponding to the corresponding second gray level and the corresponding third gray level according to a same gamma curve. 2 . The electronic circuit of claim 1 , wherein at least one of the corresponding fourth gray levels is higher than a corresponding one of the corresponding third gray levels. 3 . The electronic circuit according to claim 1 , wherein the corresponding second gray level and the corresponding third gray level are obtained according to different data processing curves. The electronic circuit according to claim 1 , wherein an average brightness of the first area is higher than an average brightness of the second area.

5. The electronic circuit according to claim 1, wherein The display driving circuit is configured to drive pixels on the display panel at a corresponding first gray level before displaying the first area, and to drive pixels of the first area at the corresponding second gray level and pixels of the second area at the corresponding third gray level after displaying the first area, The display driving circuit generates the corresponding third gray level by modifying the corresponding fourth gray level according to a data processing curve after displaying the first area.

6. An electronic circuit, adapted to drive a display panel including a touch sensor and a fingerprint sensor, wherein the electronic circuit cooperates with the display panel and an application processor to perform a fingerprint recognition operation, the electronic circuit comprising: a touch sensing circuit configured to sense a touch of a finger and determine a first area on the display panel corresponding to the touch; a display driving circuit configured to drive pixels of the first area of ​​the display panel with a display pattern indicating a fingerprint input area; a fingerprint sensing circuit configured to sense a fingerprint image of the finger corresponding to the first area of ​​the display panel; a first interface circuit, wherein when the touch is recognized as valid, the touch sensing circuit controls the fingerprint sensing circuit via the first interface circuit to start fingerprint scanning of the first area and sense the fingerprint image of the finger from the first area; as well as a second interface circuit, wherein the touch sensing circuit controls the display driving circuit via the second interface circuit to drive the pixels of the first area of ​​the display panel with the display pattern of the fingerprint input area, wherein the fingerprint sensing circuit transmits the fingerprint image to the application processor so that the application processor performs the fingerprint recognition operation, wherein the display driving circuit drives the pixels in the first area at a corresponding second grayscale level, wherein the touch sensing circuit controls the display driving circuit via the second interface circuit to drive pixels in a second area outside the first area at a corresponding third grayscale level, The display driving circuit processes the corresponding fourth gray level to obtain the corresponding third gray level, and the display driving circuit generates gamma voltages corresponding to the corresponding second gray level and the corresponding third gray level according to a same gamma curve.

7. A method for driving a display panel including a touch sensor and a fingerprint sensor, the method comprising: sensing a touch of a finger to determine a first area on the display panel corresponding to the touch; sensing a fingerprint image of the finger corresponding to the first area of ​​the display panel; driving pixels in the first area at a corresponding second gray level, and driving pixels in a second area outside the first area at a corresponding third gray level; processing the corresponding fourth gray level to obtain the corresponding third gray level; as well as Gamma voltages corresponding to the corresponding second gray level and the corresponding third gray level are generated according to the same gamma curve.

8. The method according to claim 7, wherein the corresponding second gray level and the corresponding third gray level are obtained according to different data processing curves. 9 . The method according to claim 7 , wherein an average brightness of the first area is higher than an average brightness of the second area.

10. The method according to claim 7, further comprising: driving pixels on the display panel at corresponding first gray levels before displaying the first area; driving pixels of the first region at the corresponding second gray level and driving pixels of the second region at the corresponding third gray level after displaying the first region; as well as generating the corresponding third gray level by modifying the corresponding fourth gray level according to a data processing curve after displaying the first area, The corresponding second gray level is higher than the corresponding first gray level, and the corresponding third gray level is lower than the corresponding second gray level. The method of claim 10 , wherein the corresponding third gray level is the same as the corresponding first gray level.

12. The method according to claim 10, further comprising: When the touch is recognized as valid, fingerprint scanning of the first area is initiated to sense the fingerprint image of the finger from the first area. 13 . The method of claim 10 , wherein when the detected touch area is larger than a predetermined threshold area, the touch is recognized as valid.

14. The method according to claim 10, further comprising: The pixels of the first area are driven with a display pattern indicating a fingerprint input area.

15. The method according to claim 10, further comprising: The backlight is adjusted by a pulse width modulation signal.

16. The method according to claim 15, wherein the step of adjusting the backlight by a pulse width modulation signal comprises: The brightness of the backlight is adjusted by adjusting the duty cycle of the pulse width modulation signal.

17. The method according to claim 15, wherein the step of adjusting the backlight by a pulse width modulation signal comprises: The backlight is adjusted by adjusting the frequency of the pulse width modulation signal. 18 . The method according to claim 10 , wherein a brightness of a backlight after displaying the first region is greater than a brightness of a backlight before displaying the first region.

19. The method according to claim 10, further comprising: The fingerprint image is transmitted to an application processor for performing a fingerprint recognition operation by the application processor.

20. The method according to claim 10, wherein the first area is a partial area of ​​the display panel.

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