Display driving device with burn-in compensation and display device including the same

Abstract

A display driving device includes a driving unit and a burn-in compensation device. The driving unit drives a display panel to display a display frame on the display panel. The burn-in compensation device accumulates the luminous time of each sub-pixel unit in a camera area under the screen of the display panel, and finds out the compensation gain value of each sub-pixel unit in the camera area under the screen based on the accumulated luminous time to compensate for the decayed luminous brightness of the camera area under the screen.

Description

Technical Field

[0001] The present invention relates to the technical field of display panels, and in particular to a display driving device with burn-in compensation and a display device comprising the same. Background Art

[0002] Currently, de-burn-in for display panels such as organic light emitting diodes (OLEDs) is mainly achieved by electrical compensation. Electrical compensation requires adding a current sensing circuit or a voltage sensing circuit to the pixel circuit structure of the display panel. With the cooperation of the display driving circuit, the current-voltage characteristics of the thin-film transistors of each sub-pixel of the display panel or the current-voltage characteristics of the light-emitting diodes are actively detected. Based on the difference between the sensed current or voltage and the characteristics of the display panel when it leaves the factory, calculations and compensation are performed in the display driving circuit.

[0003] Therefore, in order to compensate for the burn-in phenomenon of the display panel with the aforementioned existing electrical method, the pixel circuit structure of the display panel needs to be modified, and a large amount of information including the factory information of each sub-pixel of the display panel and the required compensation value needs to be stored, resulting in excessive calculation and memory requirements for the display driving circuit. Moreover, this burn-in compensation process is for the entire display panel, and it is not possible to arbitrarily select a local area for sensing and compensation. Therefore, the feasibility and mass production are not good, and it cannot meet actual needs.

[0004] Furthermore, in existing mobile devices such as mobile phones or tablets, in order to realize the function of full-screen selfie photography, the display panel of the mobile device adopts a camera under panel (CUP) design in which the front lens of the camera is buried under the display panel. In order to increase the light transmittance of the camera without affecting the display effect, the display panel of the existing mobile device reduces the pixel density of the display panel directly above the camera or reduces the sub-pixel size to increase the panel aperture ratio of this CUP area, so that the camera can have enough light to take pictures.

[0005] However, increasing the aperture ratio also reduces the brightness of the CUP area. In order to make the visual effect of the entire panel consistent when displaying images and prevent users from feeling that the display in the CUP area is abnormally dark, a brighter gamma setting is generally applied to the CUP area to increase the pixel current and raise the pixel brightness in the CUP area to a level close to that of the normal display area. However, since the light-emitting material of the display panel has a certain lifespan, increasing the brightness will lead to increased material loss and shorten the lifespan of the pixels.

[0006] Therefore, there are still many deficiencies in the design of the existing display panel and there is a need to improve them. Summary of the invention

[0007] The main purpose of the present invention is to provide a display driver device with burn-in compensation and a display device including the display driver device, which can effectively solve the burn-in phenomenon caused by pixel burn-in in the CUP area or the entire panel while consuming less hardware resources and without changing the display panel circuit.

[0008] According to one feature of the present invention, a display driving device is proposed, comprising: a driving unit, driving a display panel to display a display frame on the display panel, wherein the display panel has a plurality of pixel units, each pixel unit includes at least a sub-pixel unit of a specific color, and the display panel also has an under-screen camera area; and a burn-in compensation device, for accumulating the luminous time of each sub-pixel unit in the under-screen camera area, and finding out the compensation gain value of each sub-pixel unit in the under-screen camera area based on the accumulated luminous time, so as to compensate for the decayed luminous brightness of the under-screen camera area.

[0009] According to another feature of the present invention, a display driving device is proposed, including: a driving unit, driving a display panel to display a display frame on the display panel, wherein the display panel has a plurality of pixel units, each pixel unit includes at least one sub-pixel unit of a specific color; and a burn-in compensation device, for accumulating the luminous time of each sub-pixel unit of the display panel, sampling a cumulative luminous time as the average value of the cumulative luminous time of all sub-pixel units of the display panel, and finding out the compensation gain value of each sub-pixel unit of the display panel based on the cumulative luminous time to compensate for the decayed luminous brightness of the display panel.

[0010] The present invention also provides a display device including the above-mentioned display driving device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A display device according to an embodiment of the present invention is shown.

[0012] Figure 2 The structure of a burn-in compensation device and a process for compensating for the decayed luminous brightness according to an embodiment of the present invention are shown.

[0013] Figure 3 Schematically displays the cumulative luminous time information of the CUP area.

[0014] Figure 4 The cumulative luminescence time information of the CUP region after downsampling is schematically displayed.

[0015] Figure 5 A display device according to another embodiment of the present invention is shown.

[0016] Figure 6 The structure of a burn-in compensation device and a process for compensating for the decayed luminous brightness according to another embodiment of the present invention are shown.

[0017] Figure 7 Schematically displays the accumulated light emission time information of the entire display panel.

[0018] Display panel 10

[0019] Pixel unit 11 Sub-pixel unit 101

[0020] Under-screen camera (CUP) area 12

[0021] Display driving device 20

[0022] Gamma Device 30

[0023] Display frame 40

[0024] Burn mark compensation device 50

[0025] Drive unit 60

[0026] Luminous time cumulative processing 51

[0027] Downsampling Processing 52

[0028] Data storage processing 53 memory 531

[0029] Burn-in compensation processing 54 Gain lookup table 541 DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the implementation of the present invention and are not intended to limit the present invention.

[0031] Figure 1FIG. 1 is a display device according to an embodiment of the present invention, which includes a display panel 10 and a display driving device 20. The display driving device 20 includes a driving unit 60, a gamma device 30, and a burn-in compensation device 50. The driving unit 60 is used to drive the display panel 10 and convert the display data value of the display frame 40 into a gamma voltage by the gamma device 30 so as to display the display frame 40 on the display panel 10. The display panel 10 has a plurality of pixel units 11 arranged in rows and columns on the display surface. Each pixel unit 11 includes at least one In one embodiment and the following description of the present invention, each pixel unit 11 of the display panel 10 includes a red (R) sub-pixel unit 101, a green (G) sub-pixel unit 101 and a blue (B) sub-pixel unit 101, that is, the color displayed by the pixel unit 11 of the display panel 10 is a combination of three colors R / G / B. However, the present invention is not limited to the arrangement and combination of sub-pixels. In other embodiments, the sub-pixel units in the above-mentioned pixel units can also be arranged and combined in different orders. In addition, there is a camera under panel (CUP) area 12 on the display panel 10, that is, a camera is buried under the display panel 10 in the CUP area 12, and compared with the other areas of the display panel 10, the sub-pixel unit 101 of the CUP area 12 has a lower pixel density or a smaller sub-pixel size.

[0032] After excessive use, the brightness of the sub-pixel unit 101 in the CUP area 12 will decay more seriously than that of the sub-pixel units 101 in other areas of the display panel 10, resulting in a brightness difference and causing burn-in. Therefore, the present invention uses a burn-in compensation device 50 to accumulate the luminous time of the sub-pixel unit 101 in the CUP area 12, and finds the compensation gain value of the sub-pixel unit 101 in the CUP area 12 based on the accumulated luminous time to compensate for the decayed luminous brightness of the CUP area 12. Figure 1 The displayed CUP area 12 may be located at any position on the panel 10 and is not limited to the center of the panel 10 .

[0033] Figure 2 The structure of the burn-in compensation device 50 and the processing of compensating the decayed luminous brightness are shown. In the luminous time accumulation processing 51, when a display frame 40 is displayed, the luminous time (emission time) of each sub-pixel unit 101 of the CUP area 12 is accumulated for each color in real time according to the image content displayed in the CUP area 12, wherein the luminous time of a sub-pixel unit 101 is calculated according to its display linear grayscale value, display brightness value, and temperature value. More specifically, the luminous time of the sub-pixel unit 101 is obtained by the following expression:

[0034] Emission_time=linear_scale·dbv·temperature,

[0035] Emission_time is the emission time of the sub-pixel unit 101 when displaying a display frame 40; linear_scale is the linear grayscale value of the image content displayed by the sub-pixel unit 101, and the linear grayscale value is the gamma power of the display grayscale value, that is, linear_scale=scale Gamma , where scale is the display grayscale value, for example, the display grayscale value in 8-bit color depth display is 0-255, Gamma is the brightness coefficient, for example, 2.2; dbv is the display brightness value of the sub-pixel unit 101, and dbv=DBV / 2 n , where DBV represents the overall brightness, n represents the brightness depth, and the range of the calculated dbv is 0 to 1; temperature is the temperature value of the sub-pixel unit 101, where the corresponding temperature value is 0 to 2.2 when the actual temperature is 50 degrees Celsius to 70 degrees Celsius.

[0036] Therefore, each time a display frame 40 is displayed, the light emitting time of each sub-pixel unit 101 in the CPU region 12 is accumulated, that is:

[0037] AET=AET+Emission_time,

[0038] Wherein, AET is the accumulated luminous time of the sub-pixel unit 101, and its initial value is 0. And in order to comply with the calculation processing of the display driving device 20, the accumulated luminous time AET can be formulated as, for example, every 256th digit of the accumulated value is 1 unit, every 60th digit of the accumulated value is 1 second, every 60th digit of the accumulated value is 1 minute, and every 60th digit of the accumulated value is 1 hour. After the above-mentioned luminous time accumulation processing 51, the accumulated luminous time information of the CPU area 12 can be obtained, that is, as Figure 3 As shown, the accumulated light emission time information of the CUP region 12 includes the accumulated light emission time AET of each sub-pixel unit 101 of the CUP region 12 for each color (R / G / B).

[0039] Since the luminous time accumulation process 51 needs to accumulate the luminous time of each sub-pixel unit 101 in the CPU region 12, which may result in a huge amount of data, it is optional that, in the downsampling process 52, for each color, the accumulated luminous time AET of the sub-pixel unit 101 in the CPU region 12 is downsampled, so that the accumulated luminous time AET of the multiple sub-pixel units 101 is only sampled as the average value of the accumulated luminous time AET of the multiple sub-pixel units 101, thereby reducing the amount of data. For example, Figure 4 As shown, for the sub-pixel unit 101 of the same color in a specific block size of 2x2, only the accumulated luminous time AET can be sampled, which is the average value of the accumulated luminous time AET of 4 (=2x2) sub-pixel units 101, so as to obtain the accumulated luminous time information of the CUP area 12 after reduced sampling. Accordingly, the amount of data that needs to be stored can be effectively reduced. However, it should be noted that when the storage space is sufficient, there is no need to perform this reduced sampling process 52.

[0040] Next, in the data storage process 53, the accumulated luminous time information of the CUP area 12 obtained by the aforementioned luminous time accumulation process 51 or the accumulated luminous time information of the CUP area 12 obtained after the downsampling process 52 is stored in the memory 531, for example, in a static random access memory (SRAM). In order to prevent the data in the static random access memory from being cleared during an abnormal power outage, the accumulated luminous time information of the CUP area 12 can be written into the flash memory (Flash) from time to time to ensure the security of the data.

[0041] Furthermore, in the burn-in compensation process 54, for each color, a gain lookup table 541 is pre-established for searching the compensation gain value of the sub-pixel unit 101 of the CUP area 12. As shown in the figure, the gain lookup table 541 includes an accumulated luminous time item (AET) and a corresponding compensation gain value item (gain), wherein the gain value for compensating the brightness back to 100% can be inferred based on the material life curve of the sub-pixel unit, and the compensation gain value in the compensation gain value item (gain) is pre-calculated accordingly.

[0042] Therefore, the burn-in compensation process 54 uses the aforementioned pre-established gain lookup table 541 for lookup. According to the accumulated light emission time AET of the sub-pixel unit 101 in the CPU area 12, the compensation gain value of the sub-pixel unit 101 can be calculated by the gain lookup table 541 by interpolation to perform burn-in compensation:

[0043] R'=R·R_gain,

[0044] G'=G·G_gain,

[0045] B'=B·B_gain,

[0046] Wherein, R / G / B is the original red / green / blue display data value to be displayed by the red / green / blue sub-pixel unit 101, R_gain / G_gain / B_gain is the compensation gain value of the red / green / blue sub-pixel unit 101 found out, and R' / G' / B' is the compensated red / green / blue display data value displayed by the red / green / blue sub-pixel unit 101. Among them, the compensated display data value R' / G' / B' can be greater than the original display data value R / G / B to achieve the purpose of brightness compensation. Accordingly, when driving the CUP area 12 of the display panel 10, according to converting the compensated display data value into a gamma voltage by the gamma device 30, the driving unit 60 displays the image on the CUP area 12 of the display panel 10.

[0047] Since the compensated display data value is greater than the original display data value, in order to achieve effective brightness compensation, a special extended gamma architecture can be used to expand the range of the original display data value and correspond to the correct gamma voltage, thereby increasing the brightness to achieve the purpose of compensation. This extended gamma architecture can be seen in patent application number CN201911311017.8 "Extended gamma device for display panel and display device including the same" applied by the same applicant, which is provided here for reference.

[0048] Figure 5 The display device of another embodiment of the present invention is shown, and its structure is similar to the previous embodiment, but the burn-in compensation device 50 compensates for the decayed luminous brightness of the entire display panel 10. Figure 6 The structure of the burn-in compensation device 50 and the processing for compensating the decayed luminous brightness are shown. In the luminous time accumulation processing 51, when displaying a display frame 40, the luminous time (emission time) of each sub-pixel unit 101 of the display panel 10 is accumulated for each color according to the image content displayed by the display panel 10 in real time, and the accumulated luminous time AET of each sub-pixel unit 101 is obtained. Since the present embodiment compensates for the decayed luminous brightness of the entire display panel 10, for each color, the accumulated luminous time AET of all sub-pixel units 101 of the display panel 10 is only sampled. The accumulated luminous time AET is the average value of the accumulated luminous time AET of all sub-pixel units 101, such as Figure 7As shown, the amount of information data of the accumulated luminous time of the entire display panel 10 obtained by the luminous time accumulation process 51 is very small. Therefore, in the data storage process 53, the storage space of the static random access memory (SRAM) and the flash memory (Flash) required is also very small.

[0049] Furthermore, in the burn-in compensation process 54, for each color, a gain lookup table 541 is pre-established for searching the compensation gain value of the sub-pixel unit 101 of the display panel 10. This gain lookup table 541 is the same as the previous embodiment and will not be described in detail.

[0050] Therefore, the burn-in compensation process 54 uses the aforementioned pre-established gain lookup table 541 for table lookup. According to the accumulated light emission time AET of the entire display panel 10, the compensation gain value of the sub-pixel unit 101 can be calculated by the gain lookup table 541 by interpolation to perform burn-in compensation and compensate the original R / G / B display data value to be displayed with the compensation gain value to become the compensated R' / G' / B' display data value, so as to achieve the purpose of brightness compensation. Accordingly, when driving the display panel 10, according to converting the compensated display data value into a gamma voltage by the gamma device 30, the driving unit 60 displays the image on the display panel 10.

[0051] From the above description, it can be seen that the present invention can effectively solve the pixel burn-in phenomenon such as the CPU area or the entire panel by accumulating the light emission time to perform burn-in compensation, while consuming less hardware resources and without changing the display panel circuit.

[0052] The above embodiments are merely examples for the convenience of description. The scope of rights claimed by the present invention should be based on the claims, but not limited to the above embodiments.

Claims

1. A display driving device, characterized in that: include: a driving unit, driving a display panel to display a display frame on the display panel, wherein the display panel has a plurality of pixel units, each pixel unit includes at least a sub-pixel unit of a certain color, and the display panel also has an under-screen camera area; and a burn-in compensation device, used for accumulating the luminous time of each sub-pixel unit in the camera area under the screen, and looking up the compensation gain value of each sub-pixel unit in the camera area under the screen according to the accumulated luminous time, so as to compensate for the decayed luminous brightness of the camera area under the screen; wherein, for each color, a gain lookup table is pre-established for looking up the compensation gain value of the sub-pixel unit in the camera area under the screen; The light emitting time of a sub-pixel unit is calculated according to its linear grayscale value, display brightness value, and temperature value; The luminescence time is obtained by the following expression: Emission_time = linear_scale ∙dbv ∙temperature; Among them, Emission_time is the emission time of the sub-pixel unit when displaying a display frame; linear_scale is the linear grayscale value of the image content displayed by the sub-pixel unit; dbv is the display brightness value of the sub-pixel unit; and temperature is the temperature value of the sub-pixel unit.

2. The display driving device according to claim 1, wherein: The burn-in compensation device performs a downsampling process so that a plurality of sub-pixel units only samples an accumulated luminous time which is an average value of the accumulated luminous time of the plurality of sub-pixel units.

3. The display driving device according to claim 1 or 2, characterized in that: The burn-in compensation device stores the accumulated luminous time of the camera area under the screen in a static random access memory, and writes the accumulated luminous time of the camera area under the screen into a flash memory at irregular intervals.

4. The display driving device according to claim 1, wherein: The burn-in compensation device has a preset gain lookup table for looking up the compensation gain value of the sub-pixel unit in the camera area under the screen according to the accumulated light-emitting time.

5. A display device, characterized in that: include: A display panel and the display driving device as claimed in claim 1.

6. A display driving device, characterized in that: include: a driving unit, driving a display panel to display a display frame on the display panel, wherein the display panel has a plurality of pixel units, each pixel unit includes a sub-pixel unit of at least a certain color; and A burn-in compensation device is used to accumulate the luminous time of each sub-pixel unit of the display panel, sample a cumulative luminous time as an average value of the cumulative luminous time of all sub-pixel units of the display panel, and find out the compensation gain value of each sub-pixel unit of the display panel according to the cumulative luminous time to compensate for the decayed luminous brightness of the display panel; wherein, for each color, a gain lookup table is pre-established for finding the compensation gain value of the sub-pixel unit of the camera area under the screen; The light emitting time of a sub-pixel unit is calculated according to its linear grayscale value, display brightness value, and temperature value; The luminescence time is obtained by the following expression: Emission_time = linear_scale ∙dbv ∙temperature; Among them, Emission_time is the emission time of the sub-pixel unit when displaying a display frame; linear_scale is the linear grayscale value of the image content displayed by the sub-pixel unit; dbv is the display brightness value of the sub-pixel unit; and temperature is the temperature value of the sub-pixel unit.

7. The display driving device according to claim 6, wherein: The burn-in compensation device stores the accumulated luminous time of the display panel in a static random access memory, and writes the accumulated luminous time of the display panel into a flash memory at irregular intervals.

8. The display driving device according to claim 6, wherein: The burn-in compensation device has a preset gain lookup table for looking up the compensation gain value of the sub-pixel unit of the display panel according to the accumulated light-emitting time.

9. A display device, characterized in that: include: A display panel and a display driving device as claimed in claim 6.

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