TW202125494A - Display device for implementing local high brightness - Google Patents

Abstract

A display device for implementing local high brightness includes a display panel, a display driving device and an extended gamma device. The display area of the display panel includes a background area and an optical fingerprint identification area. The display driving device drives the display panel to display a display frame. The extended gamma device has 2^p gray scale values respectively corresponding to 2^p gamma voltage values, and q extended gray scale values respectively corresponding to q extended gamma voltage values, wherein q is an integer greater than or equal to 1 and less than or equal to 2^p . When the fingerprint identification is started, the display driving device maps the pixel value of the display frame to be displayed in the fingerprint identification area to an extended gray scale value from the extended gamma device, so as to select the extended gamma voltage value corresponding to the mapped extended gray scale value for driving the display panel.

Description

Display device for realizing local high brightness

The present invention relates to the technical field of display panels, in particular to a device for realizing local high brightness of the display panel.

With the increasing requirements for data security of smart phones, fingerprint recognition functions on display panels have gradually become popular. For example, under-screen optical fingerprint recognition for active matrix organic light-emitting diode (AMOLED) display panels On Display (FoD), the light source required is provided by the AMOLED display panel. The current method is to switch the AMOLED display panel from, for example, Normal Mode to High Brightness Mode (HBM) through the driver chip. Improve the overall brightness of the display panel to match the fingerprint recognition sensing.

Generally speaking, in order to switch the AMOLED display panel to HBM, the driver chip must first restore the emission duty of driving the AMOLED display panel from the state of the original emission period (such as the state in a general scene) to a full state. If the original light-emitting period is not full, this switching will cause the overall picture of the display panel to become brighter. Furthermore, the driver chip needs to switch the gamma setting used to the HBM gamma setting. As the brightness of the HBM gamma setting is higher, it will also cause the screen of the display panel to become brighter. It can be seen that although the above-mentioned optical fingerprint recognition light source provides sufficient brightness in the fingerprint pressing area, the background brightness of the display screen will also be brightened, which affects the original screen design and is easy It makes the user feel unnatural and reduces the user experience.

Therefore, in the design provided by the optical fingerprint recognition light source of the conventional display panel, there are still many shortcomings and it is necessary to improve it.

The purpose of the present invention is mainly to provide a display device that achieves local high brightness. By extending the gamma device to extend the brightness performance of the displayed data on the display panel, the brightness performance of the fingerprint recognition area can be increased to the highest level during optical fingerprint recognition. Brightness performance, and effectively avoid the problem of brightening the brightness of the background area.

In order to achieve the foregoing objective, the present invention provides a display device that achieves local high brightness, which includes: a display panel with a plurality of pixels, each pixel includes at least one specific color sub-pixel, wherein the display panel displays The area includes a background area and an optical fingerprint recognition area; a display driving device drives the display panel to display a display frame on the display panel, wherein the pixel value of the display frame is 0 to 2 ^p -1 , P is an integer greater than 1; and an extended gamma device, for each specific color, has 2 ^p grayscale values corresponding to 2p gamma voltage values, and q respectively corresponding to q extended gamma voltage values An extended gray scale value, where q is an integer greater than or equal to 1 and less than or equal to 2 ^p , wherein when fingerprint recognition is activated, the display driving device will correspond to the pixel value of the display frame displayed in the fingerprint recognition area The extended gamma device compares an extended gray scale value, and accordingly selects the extended gamma voltage value corresponding to the compared extended gray scale value to drive the display panel.

The above summary and the following detailed description are exemplary in nature, and are intended to further illustrate the scope of the patent application of the present invention. Other objectives and advantages of the present invention will be described in the following description and drawings.

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the implementation of the present invention, and are not used to limit the present invention.

FIG. 1 shows a display device of the present invention for realizing local high brightness, which includes a display panel 10, a display driving device 20, and an extended gamma device 30, wherein the display panel 10 has a structure of the display surface There are a plurality of pixels 101, and each pixel 101 includes at least one sub-pixel of a specific color. In one embodiment, each pixel 101 of the display panel 10 includes a red sub-pixel and a green sub-pixel And a blue sub-pixel, that is, the color displayed by the pixel 101 of the display panel 10 is a combination of three colors of red, green and blue. For each specific color, the extended gamma device 30 has a plurality of gray scale values and extended gray scale values, and a plurality of gamma voltage values and extended gamma values corresponding to the plurality of gray scale values and the extended gray scale values, respectively Voltage value. Based on the multiple gamma voltage values and extended gamma voltage values corresponding to multiple gray scale values and extended gray scale values provided by the extended gamma device 30, the display driving device 20 drives the display panel 10, and When the brightness of the display panel is controlled during an emission duty, a display frame 40 is displayed on the display panel 10. In an embodiment, the sub-pixel color combinations of the above-mentioned pixels may also be other permutations and combinations, so this embodiment does not limit the present invention.

The aforementioned display panel 10 provides an optical fingerprint recognition function. For example, a touch chip 50 activates the optical fingerprint recognition function of the display panel 10. When the optical fingerprint recognition function is activated, the display area of the display panel 10 is divided into one The background area 103 and a fingerprint recognition area 109 are for users to touch the optical fingerprint recognition area 109 with their fingers to perform fingerprint recognition. The fingerprint recognition area 109 can be a rectangular area, a circular area, or an ellipse. The background area 103 is the area of the display area of the display panel 10 excluding the fingerprint recognition area 109.

The aforementioned display device of the present invention supports p-bit color depth display, where p is an integer greater than or equal to 1, and p-bit color depth display means that the pixel value of the display frame 40 is a p-bit value, which is also That is, the pixel value of the display frame 40 ^{ranges from 0 to 2 p} -1. For example, for an 8-bit color depth display, the pixel value of the display frame 40 is 0 to 255, and for a 10-bit color depth display, The pixel value of the display frame 40 is 0 to 1023. For a 12-bit color depth display, the pixel value of the display frame 40 is 0 to 4095. The following description of the present invention is mainly based on an 8-bit color depth display as an example However, this is only for the convenience of understanding, and is not intended to limit the present invention.

2 is a schematic diagram of the extended gamma device 30 of the present invention. The figure shows that the color displayed in this embodiment is a combination of three colors of red, green and blue. Therefore, for each of the three colors of red, green and blue For colors, the extended gamma device 30 each has a plurality of gray scale values and extended gray scale values, and a plurality of gamma voltage values and extended gamma voltage values corresponding to the plurality of gray scale values and the extended gray scale values, respectively. As shown, for the red (R), the extension device 30 having gamma gray scale values of 2 ^p and the q extending gray level value, and to be 2 ^p gamma voltage value of the gray scale values of 2 ^p There should be q extended gamma voltage values of q extended grayscale values, where q is an integer ^{greater than or equal to 1 and less than or equal to 2p.} For example, for an 8-bit color depth display, the extended gamma device 30 has 256 gray scale values 0, 1, 2, …255 and corresponding 256 gamma voltage values RV0, RV1, RV2, …RV255, and q is an integer greater than 1 and less than 256, for example 64, the extended gamma device 30 has 64 extended gray scale values 256, 257, 258, …319 and the corresponding 64 extended gamma voltage values RV256, RV257, RV258 , …RV319. In addition, for green (G) and blue (B), the grayscale value and extended grayscale value of the extended gamma device 30, and the corresponding gamma voltage value and extended gamma voltage value are also the same, so they are not Go into details again.

In the aforementioned extended gamma device 30, the 2 ^p gray scale values and the corresponding 2 ^p gamma voltage values are the gray scale values that the standard gamma device that supports p-bit color depth display must provide And the gamma voltage value, because the function of the gamma device is to correct or compensate the brightness of the display, but in the general display mode, it will not use the highest brightness of the display panel 10 and the corresponding voltage, as shown in Figure 3 For example, the tolerable voltage range of an AMOLED display panel is 6V to 2.2V, and the gamma voltage value V0~V255 of a standard gamma device that supports 8-bit color depth display is about 6V to 2.8V. The voltage range of 2.8V to 2.2V is not used by the standard gamma device, and as shown in FIG. 3, the extended gamma device 30 of the present invention uses this voltage range to provide q extended gray scale values and Corresponding q extended gamma voltage values, wherein each of the q extended gamma voltage values is ^{outside the voltage range formed by the 2 p} gamma voltage values, and is within the tolerance of the display panel 10 Within the voltage range, for example, using this voltage range to provide 64 extended gray scale values 256, 257, 258, …319, and located outside the voltage range of 6V to 2.8V and located within the voltage range of 6V to 2.2V The 64 extended gamma voltage values V256, V257, V258, …V319, so that the display brightness corrected or compensated by the extended gamma device 30 can be increased, thereby reaching the highest brightness that the display panel 10 can express for optical Fingerprint recognition is used.

2 again, in the aforementioned extended gamma device 30, the ^2p grayscale values are increasing, the q extended grayscale values are extended from the ^2p grayscale value and are increasing, and when the display panel When 10 is a P-type metal oxide semiconductor (PMOS) type, the 2 ^p gamma voltage values are decreasing, and the q extended gamma voltage values are extended from the 2 ^p gamma voltage value and are decreasing. When the display panel 10 is of the N-type metal oxide semiconductor (NMOS) type, the 2 ^p gamma voltage values are increased, and the q extended gamma voltage values are extended from the 2 ^p gamma voltage values and For incremental.

Further, the size of the gray scale value is proportional to the brightness of the pixel 101 of the display panel 10. Similarly, the size of the extended gray scale value is proportional to the brightness of the pixel 101 of the display panel 10, and for PMOS type display panels 10. The magnitude of the gamma voltage value is inversely proportional to the brightness of the pixel 101 of the display panel 10. Similarly, the magnitude of the extended gamma voltage value is inversely proportional to the brightness of the pixel 101 of the display panel 10. For the NMOS type display panel 10, the magnitude of the gamma voltage value is proportional to the brightness of the pixel 101 of the display panel 10. Similarly, the magnitude of the extended gamma voltage value is proportional to the magnitude of the pixel 101 of the display panel 10. The brightness is directly proportional. In practical applications, the extended gamma device 30 stores N gray scale values and extended gray scale values, and corresponding N gamma voltage values and extended gamma voltage values, where N is an integer and 2>=N>=2 ^p +q, that is, the extended gamma device 30 only stores a part of the gray scale value and the extended gray scale value, and the corresponding gamma voltage value and the extended gamma voltage value, for example, only Store grayscale values 0, 8, 16, …255 and extended grayscale values 256, 264, 272, …319, and the corresponding gamma voltage values and extended gamma voltage values, and the remaining grayscale values and extended grayscale values The corresponding gamma voltage value and extended gamma voltage value are calculated by interpolation from the stored gray scale value and extended gray scale value, and the corresponding gamma voltage value and extended gamma voltage value.

1 again, the display frame 40 includes a plurality of pixel values 401 to represent the image to be displayed. When the display device displays the display frame 40 composed of the plurality of pixel values 401 on the display panel 10, the display driving device According to the content of the pixel 101 of the display panel 10, the extended gamma device 30 compares each pixel value 401 of the display frame with a grayscale value or an extended grayscale value, and then selects the comparison to obtain The display panel 10 is driven by the gamma voltage value or the extended gamma voltage value corresponding to the gray scale value or the extended gray scale value. And when the optical fingerprint recognition function is activated, in order to provide the high-brightness environment required for optical fingerprint recognition, the display panel 10 is driven with a full emission period (100% emission duty), and the display driving device 20 displays the frame 40 corresponds to the pixel value 401 of the frame area 409 of the fingerprint recognition area 109. The extension gamma device 30 compares an extension grayscale value, and selects the extension grayscale value corresponding to the contrasted extension grayscale value. According to this, the display device of the present invention can use the extended gamma device 30 to enhance the brightness performance of the fingerprint recognition area 109 to ensure that it can provide the high-brightness environment required for optical fingerprint recognition Furthermore, when fingerprint recognition is activated, the previously checked extended grayscale value and its corresponding extended gamma voltage value are respectively the qth extended grayscale value and the qth extended gamma voltage value. For example, when supporting 8-bit In the color depth display of the element, the contrasted extended grayscale value and the corresponding extended gamma voltage value are the 64th extended grayscale value (319) and the 64th extended gamma voltage value (V319) respectively, which represent The highest brightness that the pixel 101 of the display panel 10 can achieve, therefore, it can fully ensure that the fingerprint recognition area 109 has a high-brightness environment required for optical fingerprint recognition. And by providing enough high brightness, the recognition ability and efficiency of fingerprint recognition can also be improved.

Further, when the color displayed by the pixel 101 of the display panel 10 is a combination of three colors of red, green, and blue, based on the characteristics of optical fingerprint recognition, when fingerprint recognition is activated, the display driving device 20 will Corresponding to the green sub-pixel value and blue sub-pixel value of the display frame 40 displayed in the fingerprint recognition area 109, the extended gamma device 30 compares an extended gray scale value for green and blue, for example, The qth extended grayscale value is used to select the corresponding extended grayscale value for green and blue (for example, the qth extended grayscale value) corresponding to the extended gamma voltage value for green and blue (for example, the first q extends the gamma voltage value) to drive the display panel 10. Or, the display driving device 20 compares the green sub-pixel value corresponding to the display frame 40 displayed in the fingerprint recognition area 109, and the extended gamma device 30 compares the extended gray scale value for green, such as the qth The extended gray scale value is based on the selected extended gray scale value for green (for example, the qth extended gray scale value) corresponding to the extended gamma voltage value for green (for example, the qth extended gamma voltage value). The display panel 10 is driven.

In addition, when fingerprint recognition is activated, since the display panel 10 is driven with a full emission period (100% emission duty), although it can increase the brightness of the fingerprint recognition area 109 to be suitable for fingerprint recognition, it also increases The brightness of the background area 103, because this increase in brightness is not expected by the user, may lead to a poor user experience. To avoid this problem, when fingerprint recognition is activated, the display driving device 20 can adjust the pixel value 401 corresponding to the display frame 40 displayed on the background area 103 according to the variation ratio of the light-emitting period to compensate for the change in brightness. In other words, the display driving device 20 adjusts the pixel value 401 of the display frame 40 corresponding to the background area 103 to: R’= R * EM_duty, G’= G * EM_duty, B’= B * EM_duty, Among them, R, G, B are the original color values corresponding to each pixel displayed in the background area 103, and R', G', B'are the adjusted values corresponding to each pixel displayed in the background area 103 Color value, EM_duty is the percentage of light emission period when fingerprint recognition has not been activated. For example, the light-emitting period EM_duty when fingerprint recognition is not activated is 50%. Since the display panel 10 is driven with a full light-emitting period (100% emission duty) when fingerprint recognition is activated, it will be displayed in the background area 103. The pixel value is halved, so that the background area 103 can maintain the original background brightness, effectively avoiding the problem that the brightness of the background area 103 becomes bright when the fingerprint recognition is activated, which causes a poor user experience.

It can be seen from the above description that the present invention extends the brightness performance of the data displayed on the display panel by extending the gamma device. According to this, during optical fingerprint recognition, the brightness performance of the fingerprint recognition area can be improved to achieve the highest brightness performance, and It fully ensures that the fingerprint recognition area has the high-brightness environment required for optical fingerprint recognition. In addition, the display driving device adjusts the pixel value of the display frame corresponding to the background area to compensate for the change in brightness according to the change ratio of the light-emitting period. This effectively avoids the problem of brightening the brightness of the background area when fingerprint recognition is activated.

The above-mentioned embodiments are merely examples for the convenience of description, and the scope of rights claimed in the present invention should be subject to the scope of the patent application, rather than being limited to the above-mentioned embodiments.

10: Display panel 20: Display drive device 30: Extended gamma device 101: Pixel 103: background area 109: Fingerprint Recognition Area 40: display frame 401: pixel value 409: frame area 50: Touch chip

FIG. 1 is a schematic diagram of the display device of the present invention. Figure 2 is a schematic diagram of the extended gamma device of the present invention. FIG. 3 shows the comparison between the gamma voltage value of the extended gamma device of the present invention and the extended gamma voltage value and the tolerable voltage range of the display panel.

10: Display panel

20: Display drive device

30: Extended gamma device

101: Pixel

103: background area

109: Fingerprint Recognition Area

40: display frame

401: pixel value

409: frame area

50: Touch chip

Claims (13)

A display device for realizing local high brightness, comprising: a display panel with a plurality of pixels, each pixel includes at least one specific color sub-pixel, wherein the display area of the display panel includes a background area and an optical fingerprint recognition Area; a display driving device that drives the display panel to display a display frame on the display panel, wherein the pixel value of the display frame is 0 to 2 ^p -1, and p is an integer greater than or equal to 1; and a gamma-extending means for each particular color, gray scale having 2 ^p 2 ^p values correspond to the gamma voltage, and the corresponding grayscale value of q the q-th extension extending gamma voltage value, which q is an integer greater than or equal to 1 and less than or equal to 2 ^p , wherein when fingerprint recognition is activated, the display driving device will correspond to the pixel value of the display frame displayed in the fingerprint recognition area, and the extended gamma device An extended gray scale value is compared, and the extended gamma voltage value corresponding to the compared extended gray scale value is selected to drive the display panel. As described in the first item of the scope of patent application, the display device for achieving local high brightness, wherein when fingerprint recognition is activated, the extended gray scale value and its corresponding extended gamma voltage value are respectively the qth extended gray The order value and the qth extended gamma voltage value. As described in the second item of the scope of patent application, the display device with local high brightness, wherein the brightness of the display panel is controlled by a light-emitting period, and when fingerprint recognition is activated, the display panel has a full light-emitting period To drive. As described in item 3 of the scope of patent application, the display device for realizing local high brightness, wherein each pixel of the display panel includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel. As described in item 4 of the scope of patent application, the display device that realizes local high brightness, wherein when fingerprint recognition is activated, the display driving device will correspond to the green sub-pixel value and blue of the display frame displayed in the fingerprint recognition area Chromatic pixel values, the qth extended grayscale values for green and blue are compared by the extended gamma device, and the corresponding qth extended grayscale values for green and blue are selected accordingly. The qth extended gamma voltage values of green and blue are used to drive the display panel. As described in item 4 of the scope of patent application, the display device that realizes local high brightness, wherein when fingerprint recognition is activated, the display driving device will correspond to the green sub-pixel value of the display frame displayed in the fingerprint recognition area by The extended gamma device compares the qth extended grayscale value for green, and selects the qth extended gamma voltage value for green corresponding to the compared qth extended grayscale value for green to drive the display panel. As described in item 4 of the scope of patent application, the display device that realizes local high brightness, wherein when fingerprint recognition is activated, the display driving device adjusts the pixels corresponding to the display frame displayed in the background area according to the variation ratio of the light-emitting period Value to compensate for changes in brightness. As described in item 7 of the scope of patent application, the display device that realizes local high brightness, wherein, when fingerprint recognition is activated, the display driving device adjusts the pixel value of the display frame corresponding to the background area to: R’= R * EM_duty, G’= G * EM_duty, B’= B * EM_duty, Among them, R, G, B are the original color values corresponding to each pixel displayed in the background area, and R', G', B'are the adjusted color values corresponding to each pixel displayed in the background area , EM_duty is the percentage of light emission period when fingerprint recognition has not been activated. As described in the first item of the scope of patent application, the display device for realizing local high brightness, wherein, in the extended gamma device, each of the q extended gamma voltage values is located at the 2 ^p gamma voltage values The formed voltage range is outside and within the voltage range that the display panel can withstand. As described in item 9 of the scope of patent application, the display device for realizing local high brightness, wherein the ^2p gray scale values are increasing, and the q extended gray scale values are extended from the ^2p gray scale value and are increasing, The size of the gray scale value is proportional to the brightness of the pixel of the display panel, and the size of the extended gray scale value is proportional to the brightness of the pixel of the display panel. As described in item 10 of the scope of patent application, the display device for achieving local high brightness, wherein the 2 ^p gamma voltage values are decreasing, and the q extended gamma voltage values are extended by the 2 ^p gamma voltage values and In order to decrease, the magnitude of the gamma voltage value is inversely proportional to the brightness of the pixels of the display panel, and the magnitude of the extended gamma voltage value is inversely proportional to the brightness of the pixels of the display panel. For the display device described in item 10 of the scope of patent application, wherein the 2 ^p gamma voltage values are increasing, the q extended gamma voltage values are extended from the 2 ^p gamma voltage value and are increasing, and the gamma The magnitude of the voltage value is proportional to the brightness of the pixels of the display panel, and the magnitude of the extended gamma voltage value is proportional to the brightness of the pixels of the display panel. As described in item 9 of the scope of patent application, the display device for achieving local high brightness, wherein the extended gamma device stores N gray-scale values and extended gray-scale values, and corresponding N gamma voltage values and extended gamma Voltage value, where N is an integer and 2>=N>=2 ^p + q, and the gamma voltage values and extended gamma voltage values corresponding to the remaining gray scale values and extended gray scale values are from the stored gray scale The value and the extended gray scale value, and the corresponding gamma voltage value and the extended gamma voltage value are calculated by interpolation.

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