Brightness compensation method and device for display panel

Abstract

This disclosure relates to a brightness compensation method and apparatus for a display panel. The display panel includes a plurality of sub-pixel column units arranged along a first direction, each sub-pixel column unit including at least one sub-pixel column, and each sub-pixel column including a plurality of sub-pixels arranged along a second direction. The brightness compensation method of this disclosure includes: driving the display panel to emit light using an initial driving voltage to determine the actual brightness of each sub-pixel column unit; determining the sub-pixel column unit to be compensated for based on the actual brightness of each sub-pixel column unit; determining a first compensation voltage based on the actual brightness of the sub-pixel column unit to be compensated and a target brightness; obtaining a first driving voltage based on the first compensation voltage and the initial driving voltage; and driving the display panel to emit light using the first driving voltage to compensate the brightness of the sub-pixel column unit to be compensated.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically to a brightness compensation method and apparatus for a display panel. Background Technology

[0002] Quantum dot (QD) technology, with its superior optical properties such as high color gamut, high color purity, and high brightness, has become a crucial core material for next-generation display technologies. In the fabrication process of display panels, the quantum dot color conversion layer (QDCC), as the core functional layer for achieving high color purity display, has its fabrication process stability directly determining the display quality of the panel.

[0003] Currently, inkjet printing (IJP) technology has become one of the mainstream preparation methods for quantum dot color conversion layers due to its advantages such as high material utilization, low process cost, and adaptability to large-size and flexible panel fabrication. This technology precisely sprays quantum dot ink onto the corresponding area of ​​the substrate through nozzles on the printhead, and forms a uniform quantum dot color conversion layer after curing.

[0004] However, when using inkjet printing technology to prepare quantum dot color conversion layers, the limitations of the printing equipment hardware precision can easily lead to uneven brightness (Mura defects) on the display panel. Summary of the Invention

[0005] This disclosure aims to at least solve one of the technical problems existing in the prior art, and proposes a brightness compensation method and apparatus for a display panel.

[0006] To achieve the above objectives, this disclosure provides a brightness compensation method for a display panel, wherein the display panel includes a plurality of sub-pixel column units arranged along a first direction, each sub-pixel column unit including at least one sub-pixel column, and each sub-pixel column including a plurality of sub-pixels arranged along a second direction, and the brightness compensation method includes:

[0007] The display panel is driven to emit light by an initial driving voltage, and the actual brightness of each sub-pixel column unit is determined.

[0008] The sub-pixel column units to be brightness compensated are determined based on the actual brightness of each sub-pixel column unit.

[0009] The first compensation voltage is determined based on the actual brightness and target brightness of the sub-pixel column unit to be compensated;

[0010] The first driving voltage is obtained based on the first compensation voltage and the initial driving voltage;

[0011] The display panel is driven to emit light by the first driving voltage so that the brightness of the sub-pixel column unit to be compensated is compensated.

[0012] In some embodiments, the plurality of sub-pixel column units include at least one first sub-pixel column unit and at least one second sub-pixel column unit arranged alternately along a first direction, wherein, under the drive of the initial driving voltage, the actual brightness of the first sub-pixel column unit is different from the actual brightness of the second sub-pixel column unit;

[0013] The sub-pixel column units to be brightness compensated are determined based on the actual brightness of each sub-pixel column unit, including:

[0014] Determine the actual brightness of the first sub-pixel column unit and the second sub-pixel column unit respectively;

[0015] The actual brightness of one of the first sub-pixel column unit and the second sub-pixel column unit is taken as the target brightness, and the other of the first sub-pixel column unit and the second sub-pixel column unit is taken as the sub-pixel column unit to be compensated for brightness.

[0016] In some embodiments, under the drive of the initial driving voltage, the actual brightness of the first sub-pixel column unit is greater than the actual brightness of the second sub-pixel column unit;

[0017] Using the actual brightness of one of the first sub-pixel column unit and the second sub-pixel column unit as the target brightness, and using the other of the first sub-pixel column unit and the second sub-pixel column unit as the sub-pixel column unit to be brightness compensated, includes: using the actual brightness of the second sub-pixel column unit as the target brightness, and using the first sub-pixel column unit as the sub-pixel column unit to be brightness compensated.

[0018] In some embodiments, the first compensation voltage ΔVzone is obtained by the following formula:

[0019] ΔVzone=Vdata1-Vdata0

[0020]

[0021] I0=f(Vdata0)

[0022] I1=f(Vdata1)

[0023] Where LV0 is the target brightness, LV1 is the actual brightness of the sub-pixel column to be compensated, I0 is the current when the sub-pixel column is at the target brightness, I1 is the actual current of the sub-pixel column to be compensated, Vdata0 is the initial driving voltage, Vdata1 is the driving voltage required when the sub-pixel column to be compensated is at the target brightness, and f() represents the functional relationship between current and driving voltage.

[0024] In some embodiments, the brightness compensation method further includes:

[0025] Determine a reference region and a region to be compensated for brightness, wherein the region to be compensated for brightness includes at least one sub-pixel column;

[0026] Determine the actual brightness of the reference area and the actual brightness of each area to be compensated for;

[0027] The second compensation voltage is determined based on the actual brightness of the reference area and the actual brightness of each area to be compensated.

[0028] The second driving voltage is obtained based on the first driving voltage and the second compensation voltage;

[0029] The display panel is driven to emit light by the second driving voltage so that the brightness of the sub-pixel column unit to be compensated is compensated.

[0030] In some embodiments, determining a second compensation voltage based on the actual brightness of the reference region and the actual brightness of each region to be compensated includes:

[0031] Different reference regions and brightness compensation regions are set;

[0032] Determine the actual brightness of different reference areas and the actual brightness of each area to be compensated for;

[0033] Different second compensation voltages are obtained based on the actual brightness of different reference areas and the actual brightness of each area to be compensated.

[0034] Different second driving voltages are obtained based on different second compensation voltages and the first driving voltage;

[0035] The display panel is driven to emit light by different second driving voltages so that the brightness of the sub-pixel column unit to be compensated is compensated.

[0036] The luminous effect of the display panel corresponding to different second driving voltages is compared, and the final second compensation voltage is determined based on the comparison results.

[0037] In some embodiments, determining the final second compensation voltage based on the comparison result includes:

[0038] The sum of the brightness differences between the actual brightness of each compensated region after brightness compensation and the actual brightness of the reference region is calculated, and the second compensation voltage that minimizes the sum of the brightness differences is selected as the final second compensation voltage.

[0039] And / or, determine the brightness uniformity and color shift of each compensation region and the reference region after brightness compensation, and select the second compensation voltage that results in the highest brightness uniformity and the smallest color shift as the final second compensation voltage.

[0040] In some embodiments, at least two different sub-pixel column units correspond to the same first compensation voltage.

[0041] This disclosure also provides a brightness compensation device for a display panel, including a memory and a processor. The memory stores a computer program, which, when executed by the processor, can implement the display panel brightness compensation method as described in any of the above descriptions.

[0042] In some embodiments, the processor includes a plurality of digital-to-analog converters, each of which corresponds one-to-one with a sub-pixel column in the sub-pixel column unit to be brightness compensated in the display panel;

[0043] The digital-to-analog converter is configured to acquire first compensation data and second compensation data corresponding to the sub-pixel column, and convert the first compensation data and the second compensation data into a first compensation voltage and a second compensation voltage, respectively. Attached Figure Description

[0044] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0045] Figure 1 These are schematic diagrams showing the brightness distribution of images displayed on some display panels.

[0046] Figure 2 This is a flowchart of the steps of a brightness compensation method for a display panel in some embodiments of this disclosure.

[0047] Figure 3 This is a schematic diagram of the composition structure of the brightness compensation device for the display panel in some embodiments of this disclosure.

[0048] Figure 4A This is a schematic diagram of the display panel in some embodiments of this disclosure.

[0049] Figure 4B This is a schematic diagram of the display panel in some other embodiments of this disclosure.

[0050] Figure 5 This is a flowchart of the brightness compensation process of the display panel in some embodiments of this disclosure.

[0051] Figure 6 This is a schematic diagram illustrating the display effect of the display panel in some embodiments of this disclosure.

[0052] Figure 7 This is a schematic diagram comparing the compensation effects in some embodiments of this disclosure.

[0053] Figure 8This is a plan view of the display panel in some embodiments of this disclosure.

[0054] Figure 9 This is a schematic diagram of the process of brightness compensation using a first compensation voltage in some embodiments of this disclosure. Detailed Implementation

[0055] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0057] Unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0058] As used herein, “parallel” and “perpendicular” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°.

[0059] This document describes exemplary embodiments with reference to sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. Thus, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0060] Figure 1 These are schematic diagrams showing the brightness distribution of images displayed on some display panels.

[0061] In related technologies, the printhead used for inkjet printing can integrate up to 1024 nozzles. Due to inherent deviations in the nozzle manufacturing process, there are significant performance differences between different nozzles.

[0062] Taking a nozzle designed for a single print droplet volume of 8pl as an example, the actual ejected droplet volume will fluctuate between ±0.5 and 1pl. Each sub-pixel's quantum dot color conversion layer typically requires 3 to 8 drops of ink to be printed. After repeated printing, these minute differences in droplet volume accumulate, leading to significant differences in the thickness of the quantum dot color conversion layer in different areas. This thickness difference, after ink curing, will directly manifest as periodically distributed vertical stripes (mura) along the printing direction. See [reference needed] for details. Figure 1 As shown in the image. This defect severely affects the display uniformity and visual experience of the display panel, reducing product yield.

[0063] To address the aforementioned Mura defects, global brightness compensation (Demura) technology can be used to correct the brightness of the display panel, thereby improving display uniformity.

[0064] In the process of global brightness compensation, for example, the average brightness of a certain area of ​​the entire display area of ​​the display panel is usually selected as a benchmark to compensate for the brightness of other areas. However, due to problems such as IR drop in the display panel, the target brightness may deviate significantly from the actual brightness of the microscopic vertical stripes (Mura) that need to be compensated, and may even exceed the compensation range, resulting in compensation failure or poor compensation effect.

[0065] Furthermore, most global brightness compensation algorithms use grayscale compensation, but the grayscale compensation range is limited (for example, it is usually limited to ≤16 grayscale), resulting in a limited compensation adjustment range. This makes it impossible to completely offset the brightness fluctuations caused by the difference in the thickness of the quantum dot color conversion layer, and it is difficult to completely eliminate the vertical Mura defect.

[0066] Therefore, the periodic vertical stripe Mura defects generated when using inkjet printing technology to prepare quantum dot color conversion layers still severely restrict the display quality and product competitiveness of display panels.

[0067] In order to at least alleviate or solve one of the aforementioned technical problems, this disclosure provides a brightness compensation method and apparatus for a display panel.

[0068] Figure 2 This is a flowchart of the steps of a brightness compensation method for a display panel in some embodiments of this disclosure.

[0069] like Figure 2 As shown, this disclosure provides a brightness compensation method for a display panel. The display panel includes a plurality of sub-pixel column units P0 arranged along a first direction, each sub-pixel column unit P0 including at least one sub-pixel column, and each sub-pixel column including a plurality of sub-pixels arranged along a second direction.

[0070] like Figure 2 As shown, the brightness compensation method for the display panel disclosed herein includes:

[0071] Step S10: Drive the display panel to emit light using the initial driving voltage, and determine the actual brightness of each sub-pixel column unit P0. Optionally, the initial driving voltage is the driving voltage under the set grayscale condition or the voltage corresponding to the set gamma value.

[0072] Optionally, driving the display panel to emit light via an initial driving voltage includes: driving the display panel to emit light via a corresponding initial driving voltage under different set grayscale conditions or by selecting different set gamma values.

[0073] Optionally, determining the actual brightness of each sub-pixel column unit P0 includes: taking pictures of the driven display screen under different grayscale conditions or different gamma, and analyzing the pictures to obtain the actual brightness of each sub-pixel column unit P0. Alternatively, after the display panel is driven to emit light, the actual brightness of each sub-pixel column unit P0 can be determined visually.

[0074] Step S20: Determine the sub-pixel column unit P0 to be brightness compensated based on the actual brightness of each sub-pixel column unit P0.

[0075] In this step, after knowing the actual brightness of each sub-pixel column unit P0, the vertical mura caused by the uneven brightness of the sub-image sequence units can be determined. Based on this, the sub-pixel column units P0 in the normal region and the sub-pixel column units P0 with abnormal brightness can be further determined. The sub-pixel column units P0 with abnormal brightness are the sub-pixel column units P0 that need brightness compensation. The luminance of the sub-pixel column units P0 in the normal region is either the normal brightness or the target brightness.

[0076] Step S30: Determine the first compensation voltage based on the actual brightness and target brightness of the sub-pixel column unit P0 to be compensated for brightness.

[0077] In this step, the brightness compensation method can be determined based on whether the actual brightness of the sub-pixel column unit P0 to be compensated exceeds or does not reach the target brightness, and the amount of brightness compensation can be determined by the difference between the actual brightness of the sub-pixel column unit P0 to be compensated and the target brightness.

[0078] Step S40: Obtain the first driving voltage based on the first compensation voltage and the initial driving voltage.

[0079] This step can be understood as compensating the first driving voltage with a first compensation voltage. Optionally, for example, the first driving voltage is equal to the sum of the first compensation voltage and the initial driving voltage.

[0080] Step S50: Drive the display panel to emit light through the first driving voltage so that the brightness of the sub-pixel column unit P0 to be compensated is compensated.

[0081] This step is equivalent to driving the display panel with the compensated first driving voltage. In this case, the light emission of the display panel is the compensated light emission brightness. The brightness difference between the sub-pixel column unit P0 to be compensated and the sub-pixel column unit P0 in the normal area is reduced, and the brightness uniformity can be improved.

[0082] As can be seen from the above, the embodiments of this disclosure can perform individual brightness compensation for each column of vertical mura areas, thereby improving the brightness compensation effect, reducing mura defects, and improving the user experience.

[0083] In some embodiments, such as Figure 1 As shown, the plurality of sub-pixel column units P0 include at least one first sub-pixel column unit P1 and at least one second sub-pixel column unit P2 arranged alternately along a first direction. Under the driving action of the initial driving voltage, the actual brightness of the first sub-pixel column unit P1 is different from the actual brightness of the second sub-pixel column unit P2. It can be understood that under the driving action of the initial driving voltage, the first sub-pixel column unit P1 and the second sub-pixel column unit P2 form stripes with alternating bright and dark colors.

[0084] In this case, step S20: determining the sub-pixel column unit P0 to be brightness compensated based on the actual brightness of each sub-pixel column unit P0, including:

[0085] Step S21: Determine the actual brightness of the first sub-pixel column unit P1 and the second sub-pixel column unit P2 respectively.

[0086] Step S22: Take the actual brightness of one of the first sub-pixel column unit P1 and the second sub-pixel column unit P2 as the target brightness, and take the other of the first sub-pixel column unit P1 and the second sub-pixel column unit P2 as the sub-pixel column unit P0 to be compensated for brightness.

[0087] Understandably, for striped images formed by alternating bright and dark areas, sub-pixel column units P0 with normal brightness and sub-pixel column units P0 with abnormal brightness can be alternated. Therefore, after determining the actual brightness of each first sub-pixel column unit P1 and second sub-pixel column unit P2, the brightness of one of the first sub-pixel column units P1 and the second sub-pixel column unit P2 is the target brightness, or close to the target brightness. "Close to the target brightness" can be understood as the difference from the target brightness being within a threshold range. The brightness of the other of the first sub-pixel column units P1 and the second sub-pixel column unit P2 is the abnormal brightness, and correspondingly, the other of the first sub-pixel column units P1 and the second sub-pixel column unit P2 is the sub-pixel column unit P0 to be compensated for in terms of brightness.

[0088] For example, if the actual brightness of the first sub-pixel column unit P1 is close to the target brightness or falls within the target brightness range, then the actual brightness of the first sub-pixel column unit P1 can be directly used as the target brightness. If the brightness of the second sub-pixel column unit P2 is abnormal, then the second sub-pixel column unit P2 is the sub-pixel column unit P0 to be compensated for brightness. Therefore, this disclosure can use the actual brightness of the first sub-pixel column unit P1 to compensate for the actual brightness of the second sub-pixel column unit P2, thereby improving the uniformity between the brightness of the compensated second sub-pixel column unit P2 and the actual brightness of the first sub-pixel column unit P1, and improving the display effect.

[0089] Considering that the droplet volume deviation in inkjet printing is cumulative, the brightness difference between adjacent areas can directly reflect the actual impact of this cumulative deviation (rather than relying on the global average brightness benchmark), which can accurately correct local brightness unevenness and solve the problem of "large deviation between target brightness and microscopic Mura brightness" in conventional compensation.

[0090] Meanwhile, this disclosure does not require an industrial camera to fully reproduce the absolute brightness of each sub-pixel. It only requires accurate acquisition of the relative brightness difference between adjacent areas to achieve effective compensation and alleviate the impact of acquisition deviation caused by the diffraction limit and noise of the CCD camera.

[0091] Furthermore, in actual mass production, fluctuations in printing equipment and printhead size, as well as differences between screen panels, can cause periodic and width variations in vertical Mura. The difference in brightness between adjacent Mura is a "dynamic indicator" that reflects local defects in real time. Therefore, the technical solution disclosed herein does not rely on fixed partitions and can adapt to defect changes in different screens and printing states, thereby improving the universality of compensation.

[0092] In some embodiments, such as Figure 1 As shown, under the initial driving voltage, the actual brightness of the first sub-pixel column unit P1 is greater than the actual brightness of the second sub-pixel column unit P2.

[0093] Based on the printing characteristics, the greater the brightness in a region, the more significant the brightness difference caused by the quantum dot film thickness deviation, exceeding the capabilities of conventional Demura compensation. Therefore, targeted compensation is necessary. Considering the process characteristics of inkjet printing for preparing quantum dot color conversion layers, inherent deviations in the printing process (nozzle droplet volume fluctuations of ±0.5~1pl) will lead to differences in quantum dot film thickness in different regions. In this case, brightness is positively correlated with quantum dot film thickness: the thicker the film, the higher the quantum dot concentration, and the greater the luminous brightness. Therefore, regions with greater brightness are essentially regions with thicker films, and the difference in brightness between these regions and normal areas becomes more pronounced after the film thickness deviation accumulates from multiple ink drops.

[0094] Considering the periodic characteristics of printing (vertical muras are periodically distributed along the printing direction), the film thickness deviation in the brighter vertical mura areas is periodic. Targeted compensation based on this printing characteristic is necessary to offset the periodic brightness fluctuations and avoid residual mura defects. The actual brightness of one of the first sub-pixel column unit P1 and the second sub-pixel column unit P2 is used as the target brightness, and the other of the first sub-pixel column unit P1 and the second sub-pixel column unit P2 is used as the sub-pixel column unit P0 to be brightness compensated. This includes: using the actual brightness of the second sub-pixel column unit P2 as the target brightness, and using the first sub-pixel column unit P1 as the sub-pixel column unit P0 to be brightness compensated.

[0095] In this embodiment of the present disclosure, under the drive of the initial driving voltage, the actual brightness of the first sub-pixel column unit P1 is greater than the actual brightness of the second sub-pixel column unit P2. This can be understood as the quantum dot color conversion layer thickness of the sub-pixels in the first sub-pixel column unit P1 being greater. In this case, the actual brightness of the first sub-pixel column unit P1 is abnormal brightness, and the first sub-pixel column unit P1 is the sub-pixel column unit P0 to be compensated for brightness.

[0096] Optionally, the subpixels include three types: R, G, and B. R and G subpixels contain quantum dots. Droplet volume fluctuations (±0.5~1pl) and cumulative deviations from multiple droplet stacking (3~8 drops) caused by nozzle differences affect the quantum dot printing process of R and G subpixels, resulting in periodic film thickness differences in the luminescent areas of the R and G subpixels, which manifest as vertical mura along the printing direction. B subpixels do not contain quantum dots, and their brightness is determined by their own luminescent characteristics (not dependent on quantum dot film thickness). However, because the brightness of R and G subpixels is affected by film thickness due to printing deviations, a brightness difference exists between them and B subpixels. Furthermore, the periodic brightness fluctuations of R and G subpixels caused by printing contrast with the stable brightness of B subpixels, potentially making the vertical mura more pronounced. Therefore, compensation is needed specifically for the vertical mura caused by the printing characteristics.

[0097] Based on the above, it can be seen that, as Figure 1 As shown, the sub-pixel column in the first sub-pixel column unit P1, which is actually brighter, corresponds to the vertical Mura area and needs to be brightness compensated so that the brightness of the sub-pixel column in the second sub-pixel column unit P2, which is the normal display area, is the same as or close to that of the normal display area.

[0098] Therefore, in this embodiment, the vertical stripes are periodically distributed along the printing direction. Based on the brightness difference of adjacent areas (especially adjacent vertical stripes and adjacent sub-pixel columns), the brightness difference caused by the film thickness difference due to the nozzle ink droplet deviation is directly compensated. This embodiment can accurately capture such periodic micro brightness fluctuations and avoid the drawbacks of conventional global compensation which is "one-size-fits-all".

[0099] Meanwhile, the brightness difference between adjacent values ​​can be adjusted locally without being limited to a fixed compensation range of ≤16 gray levels. This can more effectively offset the brightness fluctuations caused by differences in quantum dot film thickness, especially improving areas with more significant brightness differences (such as bright vertical bars with thicker film thickness) and reducing Mura residue.

[0100] In some embodiments, the first compensation voltage ΔVzone is obtained by the following formula:

[0101] ΔVzone=Vdata1-Vdata0

[0102]

[0103] I0=f(Vdata0)

[0104] I1=f(Vdata1)

[0105] Where LV0 is the target brightness, LV1 is the actual brightness of the sub-pixel column to be compensated, I0 is the current of the sub-pixel column at the target brightness, I1 is the actual current of the sub-pixel column to be compensated, Vdata0 is the initial driving voltage, Vdata1 is the driving voltage required for the sub-pixel column to be compensated to reach the target brightness, and f() represents the functional relationship between current and driving voltage. That is, I=f(Vdata) represents the functional relationship between current I and driving voltage Vdata.

[0106] It is understandable that a sub-pixel includes a pixel driving circuit and a light-emitting unit electrically connected to the pixel driving circuit. The pixel driving circuit includes multiple transistors, including a driving transistor, which is used to drive the light-emitting unit to emit light. I=f(Vdata) represents the functional relationship between the current I and the driving voltage Vdata in the driving transistor.

[0107] For example, in one instance, the functional relationship between current I and driving voltage Vdata is as follows:

[0108] I = k° / 2(VDD - Vdata) 2

[0109] Here, k° is a conductivity parameter related to the transistor process size, and is related to parameters such as the mobility, gate oxide capacitance, and aspect ratio of the driving transistor. VDD is the power supply voltage of the pixel driving circuit.

[0110] Then I0 = k° / 2(VDD - Vdata0) 2 I1 = k° / 2(VDD - Vdata1) 2 On this basis,

[0111]

[0112] It can be transformed into:

[0113]

[0114] Therefore, we can obtain ΔVzone = Vdata1 - Vdata0 = VDD - (VDD-Vdata0)-Vdata0.

[0115] Considering the vertical mura caused by inkjet printing, the core issue is the difference in brightness caused by the difference in quantum dot film thickness. Since brightness is proportional to current, brightness can be linearly controlled by adjusting the current, which can directly and accurately offset the brightness fluctuations caused by film thickness deviation. For example, brightness can be linearly reduced by reducing the current in the corresponding area, thereby matching the target brightness of the normal area.

[0116] Furthermore, the embodiments disclosed herein do not require complex algorithms to fit the nonlinear relationship between brightness and compensation amount; brightness correction can be achieved simply by adjusting the current based on a proportional relationship, simplifying the compensation process. Simultaneously, the current adjustment response is fast, adapting to the high-efficiency compensation requirements of mass production, balancing compensation effectiveness and production efficiency.

[0117] Based on this, since the vertical bars Mura are periodically distributed along the printing direction, their brightness fluctuations are regular, and the proportional relationship between current and brightness has a stable linear characteristic. Therefore, the embodiments of this disclosure can calculate the corresponding first compensation voltage ΔVzone according to the above formula, and formulate the corresponding first compensation voltage ΔVzone pattern for the periodic brightness difference, thereby adapting to the periodicity and width changes of the vertical bars caused by the fluctuation of printing equipment / printhead size and the difference between screen panels. It does not need to rely on fixed partitions and has stronger versatility.

[0118] In some embodiments, after the display panel is driven to emit light by the first driving voltage, the brightness compensation method further includes:

[0119] Step S60: Determine the reference region and at least one region to be compensated for brightness. The region to be compensated includes at least one sub-pixel column.

[0120] Optionally, the display panel's display area includes a central area and a peripheral area surrounding the central area, wherein the central area can be used as a reference area, and the peripheral area as the area to be brightness compensated. The central area can be, for example, a screen with a resolution of 200*200.

[0121] Optionally, the area to be compensated may include three sub-pixel columns set sequentially.

[0122] Step S70: Determine the actual brightness of the reference area and the actual brightness of each area to be compensated.

[0123] The actual brightness of the reference area can be used as the actual brightness of the area to be compensated.

[0124] Step S80: Determine the second compensation voltage based on the actual brightness of the reference area and the actual brightness of each area to be compensated.

[0125] The embodiments disclosed herein are equivalent to performing full brightness compensation, and global compensation is performed directly through the second compensation voltage, thus no longer being limited by the grayscale compensation range.

[0126] Step S90: Obtain the second driving voltage based on the first driving voltage and the second compensation voltage, or it can be understood as obtaining the second driving voltage based on the first compensation voltage, the second compensation voltage, and the initial driving voltage. For example, the second driving voltage is equal to the sum of the first compensation voltage, the second compensation voltage, and the initial driving voltage.

[0127] The display panel is driven to emit light by a second driving voltage so that the brightness of the sub-pixel column unit P0 to be compensated is compensated.

[0128] The embodiments disclosed herein are equivalent to, on the basis of corresponding compensation for stripe mura by the first compensation voltage, performing global compensation for the entire display area by the second compensation voltage, thereby further improving the uniformity of the global display and minimizing the impact of stripe mura on the display effect.

[0129] In some embodiments, step S80, determining the second compensation voltage based on the actual brightness of the reference area and the actual brightness of each area to be compensated, includes:

[0130] Step S81: Set different reference areas and areas to be compensated for brightness.

[0131] For example, multiple sets of reference areas and brightness compensation areas can be set: The reference area is the center image with a resolution of 200*200, and the brightness compensation area includes three columns of sub-pixels, or each three columns of sub-pixels can be a separate brightness compensation area. The reference area is the center image with a resolution of 320*180, and the brightness compensation area includes five columns of sub-pixels, or each five columns of sub-pixels can be a separate brightness compensation area. The reference area is the center image with a resolution of 600*400, and the brightness compensation area includes six columns of sub-pixels, or each six columns of sub-pixels can be a separate brightness compensation area.

[0132] The reference area and the area to be brightness compensated can be set according to practical experience or actual needs. This disclosure will not list them all.

[0133] Step S82: Determine the actual brightness of different reference areas and the actual brightness of each area to be compensated.

[0134] Step S83: Obtain different second compensation voltages based on the actual brightness of different reference areas and the actual brightness of each area to be compensated.

[0135] In this step, the actual brightness of the reference area is used as the target brightness of the area to be compensated. For different reference areas and brightness levels to be compensated, corresponding second compensation voltages can be obtained. In this embodiment, different second compensation voltages refer to the second compensation voltages corresponding to different reference areas and brightness levels to be compensated. The specific values ​​of the second compensation voltages may be the same or different.

[0136] Step S84: Obtain different second driving voltages based on different second compensation voltages and first driving voltages.

[0137] Step S85: Compare the light emission effects of the display panel corresponding to different second driving voltages, and determine the final second compensation voltage based on the comparison results.

[0138] In this embodiment, different reference regions and regions to be compensated for brightness correspond to a specific second compensation voltage. The second compensation voltage can be used to compensate for the corresponding regions. Different second compensation voltages may achieve different brightness compensation effects; therefore, the final second compensation voltage can be selected based on the quality of the compensation effect.

[0139] In some embodiments, step S83, determining the final second compensation voltage based on the comparison result, includes: summing the brightness difference between the actual brightness of each compensation region after brightness compensation and the actual brightness of the reference region, and selecting the second compensation voltage that minimizes the sum of the brightness differences as the final second compensation voltage.

[0140] In this embodiment of the disclosure, the sum of the brightness differences between the actual brightness of each compensated area and the actual brightness of the reference area after brightness compensation is used as the evaluation criterion for the final compensation effect. Furthermore, the minimum sum of the brightness differences between the actual brightness of each compensated area and the actual brightness of the reference area after brightness compensation corresponds to the best final compensation effect, thereby ensuring the optimal final display effect.

[0141] In some other embodiments, step S83, determining the final second compensation voltage based on the comparison results, includes: determining the brightness uniformity and color deviation of each compensation area and the reference area after brightness compensation, and selecting the second compensation voltage that results in the highest brightness uniformity and the smallest color deviation as the final second compensation voltage.

[0142] For example, uniformity and color deviation can be observed directly by visual inspection. Considering that the end user of the display panel is the user, the final compensation effect can be judged by visual inspection, which can ensure the user experience of the end user.

[0143] In other embodiments, a second compensation voltage can be found that simultaneously satisfies the following conditions: minimizing the sum of brightness differences, maximizing brightness uniformity, and minimizing color deviation. This second compensation voltage is then used as the final compensation voltage to greatly improve the final compensation effect.

[0144] In some embodiments, the sub-pixel column unit P0 includes a plurality of sub-pixel columns, wherein at least two sub-pixel columns emit light of different colors.

[0145] Determining the actual brightness of each sub-pixel column unit P0 includes: acquiring image information of the display panel through an image acquisition device, analyzing the acquired image information to obtain the channel data corresponding to each color component in each sub-pixel column unit P0, and analyzing the channel data corresponding to each color component to obtain the actual brightness of each sub-pixel column unit P0.

[0146] For example, embodiments of this disclosure can use an industrial camera to take pictures of a set test scene, and then analyze the pictures to obtain the sub-pixel column unit P0 of the normal area and the sub-pixel column unit P0 to be brightness compensated.

[0147] In other embodiments, the distribution of mura stripes can be determined directly by visual inspection, thereby identifying the sub-pixel column unit P0 of the normal area and the sub-pixel column unit P0 to be brightness compensated.

[0148] In some embodiments, at least two different sub-pixel column units P0 to be compensated for brightness have the same first compensation voltage. Optionally, all sub-pixel column units P0 to be compensated for brightness have the same first compensation voltage.

[0149] Based on the printing characteristics, the brightness of different sub-pixel columns P0 to be compensated for brightness is similar. Therefore, the same first compensation voltage can be used to compensate each sub-pixel column to be compensated for brightness, reducing the amount of data calculation and lowering the cost.

[0150] This disclosure also provides a brightness compensation device for a display panel.

[0151] Figure 3 This is a schematic diagram of the composition structure of the brightness compensation device for the display panel in some embodiments of this disclosure.

[0152] like Figure 3 As shown, the brightness compensation device for the display panel provided in this disclosure includes a memory and a processor 20. The memory stores a computer program, and when the computer program is executed by the processor 20, it can implement the display panel brightness compensation method as described above.

[0153] In some embodiments, the processor disclosed herein includes a plurality of digital-to-analog converters (DAC modules), each DAC corresponding one-to-one with a sub-pixel column in the sub-pixel column unit P0 of the display panel to be brightness compensated.

[0154] For example, the digital-to-analog converter corresponds one-to-one with the sub-pixel column in the sub-pixel column unit P0 of the display panel that needs brightness compensation. Alternatively, the digital-to-analog converter corresponds one-to-one with the sub-pixel column in the display panel.

[0155] The digital-to-analog converter is configured to acquire first compensation data and second compensation data corresponding to the sub-pixel column, and convert the first compensation data and second compensation data into a first compensation voltage and a second compensation voltage, respectively.

[0156] Optionally, the brightness compensation device further includes a data acquisition module 10, which is used to acquire the brightness information of each sub-pixel column of the display panel and determine the sub-pixel column unit P0 to be brightness compensated.

[0157] Optionally, the brightness compensation device further includes a compensation module 30, which is used to perform brightness compensation on the display panel using a first compensation voltage and a second compensation voltage.

[0158] Alternatively, the brightness compensation device may be, for example, a driver chip (IC).

[0159] In some embodiments, the processor disclosed herein includes multiple digital-to-analog converters (DAC modules), with each DAC module corresponding to a sub-pixel column. That is, each sub-pixel column can be equipped with a separate DAC module. In this case, a corresponding compensation voltage can be obtained for each sub-pixel column, thereby achieving individual compensation for each sub-pixel column.

[0160] The brightness compensation device has an independent digital-to-analog converter (DAC) (Vdata, 10-bit) for each column, which allows for fine-tuning of the driving voltage Vdata for each sub-pixel column, thereby completing the brightness compensation for each sub-pixel column.

[0161] Therefore, the embodiments of this disclosure can be individually debugged for each display panel, thereby achieving targeted compensation for each display panel and ultimately ensuring the optimal display effect of each display panel after compensation.

[0162] Optionally, the brightness compensation device may also include two storage modules: an SRAM-A module and an SRAM-B module. The SRAM-A module stores the first compensation data, and the SRAM-B module stores the second compensation data. The digital-to-analog converter (DAC) can convert the first compensation data and the second compensation data into a first compensation voltage ΔVzone and a second compensation voltage ΔVglobal, respectively.

[0163] In this embodiment, the number of digital-to-analog converter (DAC) channels (10 bits) is determined by the resolution of the display panel. It should be noted that each DAC is equivalent to a small gamma unit, and the voltage output of each DAC falls within the range of VGMH and VGML supported by the brightness compensation device. VGMH and VGML are the logic high and logic low level voltages of the gate scan signal output by the driver chip.

[0164] After acquiring the screen display data, the brightness compensation device analyzes it to determine the specific location of the column stripe mura and the first compensation voltage ΔVzone and the second compensation voltage ΔVglobal that need to be compensated. The corresponding first and second compensation data are then stored in the SRAM-A and SRAM-B modules. The digital-to-analog converter (DAC) acquires the first and second compensation data and converts them into the first compensation voltage ΔVzone and the second compensation voltage ΔVglobal. The DAC then combines the first and second compensation voltages and feeds them back to the compensation module for brightness compensation. All DACs must be updated within each frame period to prevent horizontal mura. Unused DACs can be set to a shutdown function to prevent excessive power consumption.

[0165] Because the size of printing equipment and printheads can vary, and there are differences between display panels, the periodicity and width of the stripes differ from one display to another, and the stripe micro-areas of different display panels need to be dynamically adjusted.

[0166] Figure 4A This is a schematic diagram of the display panel in some embodiments of this disclosure, specifically a schematic diagram of the first display panel PNL1. Figure 4B This is a display schematic diagram of a display panel in some other embodiments of this disclosure, specifically a display schematic diagram of the second display panel PNL2.

[0167] like Figure 4A and Figure 4B As shown, the first display panel PNL1 and the second display panel PNL2 are two products from different batches, with different stripe periods and widths.

[0168] The first display panel, PNL1, has a stripe mura period of 3 columns of pixels and a width of 3 columns of pixels. The column numbers in the diagram represent the column numbers of the sub-pixel columns. Columns 1-3 are normally luminous areas; columns 4-6 are abnormally luminous areas, forming micro-area 1. Columns 7-9 are normally luminous areas; columns 10-12 are abnormally luminous areas, forming micro-area 2. Columns 13-15 are normally luminous areas; columns 16-18 are abnormally luminous areas, forming micro-area 3, and so on. Columns 1-3, 7-9, and 13-15 are not shown in the diagram. Micro-areas 1, 2, 3… correspond to sub-pixel column units P0 to be compensated for brightness, and each sub-pixel column unit P0 includes three columns of subpixels.

[0169] The micro-area is composed of all the abnormally bright stripe mura areas (micro-area 1, 2, 3...).

[0170] The second display panel, PNL2, has a stripe mura period of 5 columns of pixels, with a width of 5 columns of pixels. Columns 1-5 are normal luminous areas, columns 6-10 are abnormal luminous areas forming micro-area 1. Columns 11-15 are normal luminous areas, columns 16-20 are abnormal luminous areas forming micro-area 2. Columns 20-25 are normal luminous areas, columns 26-30 are abnormal luminous areas forming micro-area 3, and so on. Columns 1-5, 11-15, and 21-25 are not shown in the diagram. Micro-areas 1, 2, 3… correspond to sub-pixel column units P0 to be compensated for brightness, and each sub-pixel column unit P0 consists of five columns of subpixels.

[0171] After the industrial camera collects the mura information, the brightness compensation device will perform data acquisition and analysis to divide the mura micro-area. According to the printing characteristics, the brightness values ​​of the mura micro-area 1 / 2 / ... are very small and there is a significant brightness difference with the normal area. Based on the relationship between brightness and Vdata, the ΔVzone of the micro-area can be determined (refer to the calculation formula in the embodiment). Optionally, the entire mura micro-area can share the same set of ΔVzone.

[0172] Figure 5 This is a flowchart of the brightness compensation process of the display panel in some embodiments of this disclosure.

[0173] In one example, such as Figure 5 As shown, the specific compensation process of the brightness compensation method for the display panel provided in this disclosure includes:

[0174] Step 1: Acquire image data of the display screen using an industrial camera, and analyze the image data. For example, the brightness information of the R, G, and B channels at different gray levels (such as 32, 64, 128, 192, 255) can be acquired to extract the characteristic parameters of each sub-pixel, thereby determining the distribution of the stripe mura, and then determining the sub-pixel column unit P0 to be compensated for brightness.

[0175] like Figure 1 As shown, taking a 1920*720 resolution display panel as an example, at a certain grayscale, the stripe Mura period (interval) of this display panel is 3 columns, and the width of the mura area is 3 columns. The mura area represents the sub-pixel column unit P0 to be compensated for brightness, and the mura period can be understood as the normal area.

[0176] Step Two: Based on the mura characteristics, the display panel is divided into zones according to actual brightness. Specifically, based on the brightness difference between the mura zone and the normal zone, the first compensation voltage ΔVzone, also known as the micro-zone compensation voltage ΔVzone, is determined. The brightness of the normal zone is equal to or close to the target brightness.

[0177] Taking G255 image as an example, G255 image can be understood as a pure white (or highest grayscale) image where all pixels are at maximum brightness (255).

[0178] Figure 6 This is a schematic diagram illustrating the display effect of the display panel in some embodiments of this disclosure.

[0179] like Figure 6 As shown, the average brightness of the severe demura area is 73 nits, while the normal area is 52 nits. In this case, the demura area exceeds the normal demura grayscale compensation range. Specifically, the normal demura grayscale compensation range is ≤16gray, while the current compensation needs to be 40gray to achieve the target, which is far beyond the normal demura grayscale compensation range.

[0180] Where 52 nits corresponds to Vdata0 of 4.05V, according to the formula Vdata1=(Vdata0-VDD)* With +VDD, it can be calculated that 73nit requires Vdata1 to be 3.95V, and ΔVzone=Vdata1-Vdata0=0.1V.

[0181] By analogy, the ΔVzone corresponding to other gray levels can be determined, thereby obtaining the first voltage compensation corresponding to different gray levels.

[0182] Figure 7 This is a schematic diagram comparing the compensation effects in some embodiments of this disclosure.

[0183] like Figure 7 As shown in the figure, comparing the effect diagrams before and after micro-area compensation, it can be seen that after performing brightness micro-area compensation through the first compensation voltage ΔVzone in step two, the mura stripe phenomenon is greatly improved.

[0184] Step 3: Within the entire image area, take the actual brightness of the central area of ​​the image as the target brightness, and calculate the second compensation voltage ΔVglobal, which can also be called the global compensation voltage ΔVglobal. The central area can be determined as needed.

[0185] ΔVglobal=argminΣ{L_target-[L_zone+L(ΔVglobal)]}

[0186] Here, argmin represents the value of the variable ΔVglobal when the subsequent function reaches its minimum. L_target represents the target brightness, i.e., the actual brightness of the central region. L_zone represents the actual brightness of the area to be compensated. L(ΔVglobal) represents the compensated brightness generated by the second compensation voltage ΔVglobal.

[0187] That is, among all possible values ​​of ΔVglobal, the ΔVglobal value that minimizes Σ{L_target-[L_zone+L(ΔVglobal)]} is selected as the final global second compensation voltage.

[0188] After completing the micro-area compensation using the first compensation voltage ΔVzone, as follows Figure 7 As shown, the periodic stripe mura on the screen is significantly improved. Building on this, a second compensation voltage ΔVglobal can be used for global compensation, further optimizing overall brightness difference details.

[0189] Optionally, the center area of ​​the image is used as the reference area, and correspondingly, the brightness of the center area is used as the target brightness. For example, the center area includes 200*200 sub-pixels, and the brightness is the average brightness of each sub-pixel within that area. The brightness compensation area can be set by column partitioning, for example, 3 columns of sub-pixels per brightness compensation area, or 5 columns of sub-pixels per brightness compensation area. That is, embodiments of this disclosure can set multiple sets of reference areas and brightness compensation areas with different combinations.

[0190] Optionally, for example, three or more different second compensation voltages ΔVglobal can be obtained according to different selections of the reference area and the area to be compensated for brightness. The area to be compensated is then compensated using different second compensation voltages ΔVglobal, thereby obtaining the compensated brightness. Here, [L_zone+L(ΔVglobal)] can be understood as the obtained compensated brightness.

[0191] That is, for each set of reference areas and brightness compensation areas, the corresponding Σ{L_target-[L_zone+L(ΔVglobal)]} can be calculated, where the second compensation voltage ΔVglobal that makes Σ{L_target-[L_zone+L(ΔVglobal)]} reach its minimum value is the final second compensation voltage ΔVglobal.

[0192] By analogy, other gray levels ΔVglobal can be determined, thereby obtaining the second compensation voltage corresponding to different gray levels.

[0193] Optionally, the actual brightness can be determined visually, using a brightness measurement device, or through photographic analysis.

[0194] After completing step three, the brightness compensation method in this embodiment is equivalent to superimposing ΔVzone and ΔVglobal and then adding them to the initial driving voltage Vdata0 to obtain the final driving voltage. The display panel is then driven by the final driving voltage to complete the overall mura compensation.

[0195] Figure 8 This is a plan view of the display panel in some embodiments of this disclosure.

[0196] In another specific embodiment, such as Figure 8 As shown, taking a display panel with a resolution of 1920*720 (that is, the display panel subpixels include 720 subpixel columns and 1920 subpixel rows, each subpixel row includes 720 subpixels, and each subpixel column includes 1920 subpixels) as an example, the subpixels in the display panel include three types of subpixels: R, G, and B. The R, G, and B subpixels emit red light, green light, and blue light, respectively.

[0197] Step 1: After the setting screen is displayed on the driver display panel, image data is acquired through an industrial camera CCD (charge coupled device). Based on the captured image data, the brightness information of the R, G, and B channels at gray levels 32, 128, and 255 is acquired respectively. Then, the characteristic parameters of each sub-pixel are extracted, and the distribution of the stripe mura is finally determined based on the characteristic parameters of each sub-pixel.

[0198] like Figure 8 As shown, the position of the stripes can be determined based on the brightness (unit: nit) distribution. Knowing the actual brightness of both the normal region and the mura region, the actual brightness of the normal region can be used as the target brightness. The brightness differences between sub-pixels in the normal region are small and indistinguishable to the human eye; therefore, the average, median, or any of these values ​​can be used as the target brightness.

[0199] Alternatively, after the display panel shows the settings screen, the distribution of the stripes (mura) can be determined visually. This is because the brightness difference between the mura area and the normal area is relatively large, making it easily observable to the human eye. Areas where the human eye cannot distinguish brightness do not require brightness compensation.

[0200] Taking the G255 display panel with a resolution of 1920*720 as an example, the stripe mura cycle is approximately 3 columns, meaning the image mura consists of 3 columns of bright stripes and 3 columns of dark stripes alternating. Due to the characteristics of the printing process, the 3 columns of bright stripes are identified as the mura area, i.e., the sub-pixel column unit P0 that needs brightness compensation. The 3 columns of dark stripes are the normal area.

[0201] Step 2: Calculate the first compensation voltage ΔVzone and use it for global micro-area compensation. For example, in a pixel driving circuit, the pixel current formula is I = k° / 2(VDD - Vdata). 2Given the brightness of the normal region and the mura region, and based on the fact that brightness is proportional to current, ΔVzone can be calculated.

[0202] For example, VDD is a fixed value of 4.6V, and Vdata0 can be determined through the initial gamma adjustment of the product. Based on the brightness information of the G255 screen, the brightness value of the normal area LV0 and the brightness value of the mura area LV1 can be determined. The current Vdata0 of the G255 screen on the display panel is 3.8V. ΔVzone = Vdata1 - Vdata0, so the formula for calculating ΔVzone of the G255 screen can be derived: ΔVzone = -0.8 * +0.8.

[0203] Figure 9 This is a schematic diagram of the process of brightness compensation using a first compensation voltage in some embodiments of this disclosure.

[0204] like Figure 9 As shown, ΔVzone=0 in the normal region indicates that the brightness of the normal region does not need to be compensated. The ΔVzone in the Mura region, i.e., the sub-pixel column unit P0 to be compensated, can be calculated according to the aforementioned formula, thereby achieving individual compensation for each sub-pixel column.

[0205] Optionally, the ΔVzone corresponding to each sub-pixel column unit P0 is the same. The ΔVzone corresponding to each sub-pixel column in the same sub-pixel column unit P0 is the same, and the average value of the ΔVzone in any sub-pixel column can be taken.

[0206] After global micro-area compensation was performed using the first compensation voltage ΔVzone, the effect was as follows: Figure 7 As shown.

[0207] It should be noted that in this step, the pixel driving circuit used may differ for different display panels. The calculation formula for the pixel current I may differ for different pixel driving circuits. Those skilled in the art can derive it themselves based on the relationship between current I and driving voltage Vdata and I0 / LV0=I1 / LV1 (brightness is proportional to current). The pixel current formula shown in the embodiments of this disclosure is not intended to be a specific limitation.

[0208] Step 3: After completing micro-area compensation using the first compensation voltage ΔVzone, since the average brightness of the corresponding normal area is used as the target brightness during each micro-area compensation, slight mura still exists in the compensated image. The average brightness of the middle area can be used as the target value to perform global compensation again on the mura area.

[0209] Due to the large inter-panel differences in the current products, some display panels may experience over-compensation or under-compensation during actual compensation. Therefore, three sets of compensation values ​​are saved (by changing the number of pixels in the selected middle area to change the target compensation value), and the final value is determined based on the brightness effect after compensation.

[0210] As shown in the table below, the average brightness of the central region, which includes 640*240, 1280*480, and 1920*720 sub-pixels respectively, is used as the target brightness. Three sets of second compensation voltages ΔVglobal are determined respectively. The actual compensation effect or the uniformity of measured brightness is observed visually, and the optimal second compensation voltage ΔVglobal is selected as the final compensation value.

[0211]

[0212] As shown in the table above, after using the second compensation voltage of the third group as the compensation parameter, the compensated image has no obvious color shift and the measured brightness uniformity reaches more than 90%. Therefore, the third group of compensation parameters can be selected as the final compensation value.

[0213] In summary, this disclosure divides the display area into dynamically adjustable micro-zones, i.e., sub-pixel column units P0 to be compensated. The micro-zones change periodically with the printed mura stripes. Within each micro-zone, a zone compensation voltage ΔVzone is calculated based on the correspondence between brightness and Vdata. Furthermore, within the entire image range, a global compensation voltage ΔVglobal is calculated with the brightness of the center of the image as the target. Finally, the overall mura compensation can be completed by superimposing ΔVzone and ΔVglobal, thereby greatly improving the mura defect.

[0214] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A brightness compensation method for a display panel, the display panel comprising a plurality of sub-pixel column units arranged along a first direction, the sub-pixel column unit comprising at least one sub-pixel column, the sub-pixel column comprising a plurality of sub-pixels arranged along a second direction, characterized in that, The brightness compensation method includes: The display panel is driven to emit light by an initial driving voltage, and the actual brightness of each sub-pixel column unit is determined. The sub-pixel column units to be brightness compensated are determined based on the actual brightness of each sub-pixel column unit. The first compensation voltage is determined based on the actual brightness and target brightness of the sub-pixel column unit to be compensated; The first driving voltage is obtained based on the first compensation voltage and the initial driving voltage; The display panel is driven to emit light by the first driving voltage so that the brightness of the sub-pixel column unit to be compensated is compensated.

2. The brightness compensation method for a display panel according to claim 1, characterized in that, The plurality of sub-pixel column units include at least one first sub-pixel column unit and at least one second sub-pixel column unit arranged alternately along a first direction. Under the drive of the initial driving voltage, the actual brightness of the first sub-pixel column unit is different from the actual brightness of the second sub-pixel column unit. The sub-pixel column units to be brightness compensated are determined based on the actual brightness of each sub-pixel column unit, including: Determine the actual brightness of the first sub-pixel column unit and the second sub-pixel column unit respectively; The actual brightness of one of the first sub-pixel column unit and the second sub-pixel column unit is taken as the target brightness, and the other of the first sub-pixel column unit and the second sub-pixel column unit is taken as the sub-pixel column unit to be compensated for brightness.

3. The brightness compensation method for a display panel according to claim 2, characterized in that, Under the initial driving voltage, the actual brightness of the first sub-pixel column unit is greater than the actual brightness of the second sub-pixel column unit; Using the actual brightness of one of the first sub-pixel column unit and the second sub-pixel column unit as the target brightness, and using the other of the first sub-pixel column unit and the second sub-pixel column unit as the sub-pixel column unit to be brightness compensated, includes: using the actual brightness of the second sub-pixel column unit as the target brightness, and using the first sub-pixel column unit as the sub-pixel column unit to be brightness compensated.

4. The brightness compensation method for a display panel according to claim 1, characterized in that, The first compensation voltage ΔVzone is obtained by the following formula: ΔVzone=Vdata1-Vdata0 I0=f(Vdata0) I1=f(Vdata1) Where LV0 is the target brightness, LV1 is the actual brightness of the sub-pixel column to be compensated, I0 is the current when the sub-pixel column is at the target brightness, I1 is the actual current of the sub-pixel column to be compensated, Vdata0 is the initial driving voltage, Vdata1 is the driving voltage required when the sub-pixel column to be compensated is at the target brightness, and f() represents the functional relationship between current and driving voltage.

5. The brightness compensation method for a display panel according to any one of claims 1 to 4, characterized in that, The brightness compensation method further includes: Determine a reference region and a region to be compensated for brightness, wherein the region to be compensated for brightness includes at least one sub-pixel column; Determine the actual brightness of the reference area and the actual brightness of each area to be compensated for; The second compensation voltage is determined based on the actual brightness of the reference area and the actual brightness of each area to be compensated. The second driving voltage is obtained based on the first driving voltage and the second compensation voltage; The display panel is driven to emit light by the second driving voltage so that the brightness of the sub-pixel column unit to be compensated is compensated.

6. The brightness compensation method for a display panel according to claim 5, characterized in that, The second compensation voltage is determined based on the actual brightness of the reference area and the actual brightness of each area to be compensated, including: Different reference regions and brightness compensation regions are set; Determine the actual brightness of different reference areas and the actual brightness of each area to be compensated for; Different second compensation voltages are obtained based on the actual brightness of different reference areas and the actual brightness of each area to be compensated. Different second driving voltages are obtained based on different second compensation voltages and the first driving voltage; The display panel is driven to emit light by different second driving voltages so that the brightness of the sub-pixel column unit to be compensated is compensated. The luminous effect of the display panel corresponding to different second driving voltages is compared, and the final second compensation voltage is determined based on the comparison results.

7. The brightness compensation method for a display panel according to claim 6, characterized in that, The final second compensation voltage is determined based on the comparison results, including: The sum of the brightness differences between the actual brightness of each compensation region after brightness compensation and the actual brightness of the reference region is calculated, and the second compensation voltage that minimizes the sum of the brightness differences is selected as the final second compensation voltage. And / or, determine the brightness uniformity and color shift of each compensation region and the reference region after brightness compensation, and select the second compensation voltage that results in the highest brightness uniformity and the smallest color shift as the final second compensation voltage.

8. The brightness compensation method for a display panel according to any one of claims 1 to 4, characterized in that, At least two different sub-pixel column units have the same first compensation voltage.

9. A brightness compensation device for a display panel, characterized in that, It includes a memory and a processor, the memory storing a computer program that, when executed by the processor, enables the display panel brightness compensation method as described in any one of claims 1 to 8.

10. The brightness compensation device for the display panel according to claim 9, characterized in that, The processor includes multiple digital-to-analog converters, each of which corresponds one-to-one with a sub-pixel column in the sub-pixel column unit to be brightness compensated in the display panel. The digital-to-analog converter is configured to acquire first compensation data and second compensation data corresponding to the sub-pixel column, and convert the first compensation data and the second compensation data into a first compensation voltage and a second compensation voltage, respectively.

Images