Brightness compensation device, display system, and method for compensating the brightness of display panel

Abstract

A brightness compensation device, a display system, and a method for compensating the brightness of a display panel are provided. The brightness compensation device includes: a brightness characteristic value calculator, which calculates a first brightness characteristic value corresponding to a first unit interval between a first reference gray level and a second reference gray level, and a second brightness characteristic value corresponding to a second unit interval between the second reference gray level and the third reference gray level, based on a first brightness value, a second brightness value, and a third brightness value; a desired correction gray level calculator, which calculates a desired correction gray level corresponding to the first reference gray level based on the first brightness value; and a compensation gray level calculator, which calculates a gamma compensation value based on the first brightness characteristic value when the desired correction gray level is included in the first unit interval, and calculates a gamma compensation value based on the first brightness characteristic value and the second brightness characteristic value when the desired correction gray level is included in the second unit interval.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0069608, filed on June 9, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a brightness compensation device for providing optical compensation for a display panel, a display system including the brightness compensation device, and a method for compensating the brightness of a display panel. Background Technology

[0004] During the manufacturing process of a display device, an inspection process can be performed to detect display non-uniformities in the display panel, such as the Mura effect. If non-uniformity is detected during the inspection process, the corresponding display panel can undergo brightness compensation processing to compensate for the non-uniformity.

[0005] As an example of brightness compensation processing, optical compensation processing can be employed. According to optical compensation processing, a predetermined image is displayed on a display panel, the image displayed on the display panel is captured using a camera or the like, and the captured image is analyzed to compensate for uneven brightness in the display. Summary of the Invention

[0006] This disclosure provides a brightness compensation device that can improve display quality by accurately calculating the gamma compensation value used for optical compensation.

[0007] A brightness compensation device according to an embodiment of the present disclosure may include: a brightness characteristic value calculator, which calculates a first brightness characteristic value corresponding to a first unit interval between the first reference gray level and the second reference gray level, and a second brightness characteristic value corresponding to a second unit interval between the second reference gray level and the third reference gray level, based on two of a first brightness value corresponding to a first reference gray level, a second brightness value corresponding to a second reference gray level greater than the first reference gray level, and a third brightness value corresponding to a third reference gray level greater than the second reference gray level; a desired correction gray level calculator, which calculates a desired correction gray level corresponding to the first reference gray level based on the first brightness value; and a compensation gray level calculator, which calculates a gamma compensation value and calculates a first compensation gray level corresponding to the first reference gray level based on the gamma compensation value and the desired correction gray level. The compensation gray level calculator may calculate the gamma compensation value based on the first brightness characteristic value in a first case where the desired correction gray level is included in the first unit interval, and calculate the gamma compensation value based on the first brightness characteristic value and the second brightness characteristic value in a second case where the desired correction gray level is included in the second unit interval.

[0008] In an embodiment, in the second case, the grayscale compensation calculator can calculate the gamma compensation value using the following first equation:

[0009]

[0010] Wherein, γt can represent the gamma compensation value, γ1 can represent the first luminance characteristic value, γ2 can represent the second luminance characteristic value, g1 can represent the first reference gray level, g2 can represent the second reference gray level, and gt can represent the desired correction gray level.

[0011] In an embodiment, the luminance characteristic value calculator can calculate a first luminance characteristic value based on a first luminance value and a second luminance value, and calculate a second luminance characteristic value based on a second luminance value and a third luminance value.

[0012] In this embodiment, the luminance characteristic value calculator can calculate the first luminance characteristic value and the second luminance characteristic value using the following second equation:

[0013]

[0014] Wherein, γ1 can represent the first brightness characteristic value, γ2 can represent the second brightness characteristic value, L1 can represent the first brightness value, L2 can represent the second brightness value, L3 can represent the third brightness value, g1 can represent the first reference gray level, g2 can represent the second reference gray level, and g3 can represent the third reference gray level.

[0015] In an embodiment, the grayscale calculator is expected to calculate the brightness compensation rate based on the difference between a first brightness value and a first brightness target value corresponding to a first reference grayscale level.

[0016] In this embodiment, the grayscale level correction calculator is expected to calculate the brightness compensation rate using the following third equation:

[0017]

[0018] Wherein, LCR can represent the brightness compensation rate, LT can represent the first brightness target value, and L1 can represent the first brightness value.

[0019] In this embodiment, the desired gray level correction calculator can calculate the desired gray level using the following fourth equation:

[0020]

[0021] Where gt can represent the desired gray level to be corrected, g1 can represent the first reference gray level, and LCR can represent the brightness compensation rate.

[0022] In this embodiment, the grayscale compensation calculator can calculate the first grayscale compensation level using the following fifth equation:

[0023]

[0024] Where gcv can represent the first compensated gray level, g1 can represent the first reference gray level, LCR can represent the brightness compensation rate, and γt can represent the gamma compensation value.

[0025] In an embodiment, the luminance characteristic value calculator can also calculate a third luminance characteristic value corresponding to a third unit interval between the third reference gray level and the fourth reference gray level based on a third luminance value and a fourth luminance value corresponding to a fourth reference gray level greater than the third reference gray level. In a third case where the gray level to be corrected is to be included in the third unit interval, the compensation gray level calculator can calculate a gamma compensation value based on a first luminance characteristic value, a second luminance characteristic value, and a third luminance characteristic value.

[0026] In an embodiment, under the third case, the grayscale compensation calculator can calculate the gamma compensation value using the following sixth equation:

[0027]

[0028] Wherein, γt can represent the gamma compensation value, γ1 can represent the first brightness characteristic value, γ2 can represent the second brightness characteristic value, γ3 can represent the third brightness characteristic value, g1 can represent the first reference gray level, g2 can represent the second reference gray level, g3 can represent the third reference gray level, and gt can represent the desired correction gray level.

[0029] In an embodiment, the compensation gray level calculator can also calculate the second compensation gray level corresponding to the second reference gray level and the third compensation gray level corresponding to the third reference gray level, and calculate the compensation gray level corresponding to the entire gray level area by applying linear interpolation and / or linear extrapolation to the first compensation gray level, the second compensation gray level and the third compensation gray level.

[0030] A display system according to an embodiment of the present disclosure may include: a brightness compensation device that provides first reference image data, second reference image data, and third reference image data corresponding to a first reference gray level, a second reference gray level, and a third reference gray level, respectively; a display panel that displays the first reference gray level image, the second reference gray level image, and the third reference gray level image based on the first reference image data, the second reference image data, and the third reference image data; and an imaging unit that captures the first reference gray level image, the second reference gray level image, and the third reference gray level image, generates first captured image data, second captured image data, and third captured image data, and provides the first captured image data, the second captured image data, and the third captured image data to the brightness compensation device. The brightness compensation device may include: a brightness characteristic value calculator, which calculates a first brightness characteristic value corresponding to a first unit interval between a first reference gray level and a second reference gray level based on first captured image data and second captured image data, and calculates a second brightness characteristic value corresponding to a second unit interval between a second reference gray level and a third reference gray level based on second captured image data and third captured image data; a desired correction gray level calculator, which calculates a desired correction gray level corresponding to the first reference gray level based on the first captured image data; and a compensation gray level calculator, which calculates a gamma compensation value, and calculates a compensation gray level corresponding to the first reference gray level based on the gamma compensation value and the desired correction gray level. The compensation gray level calculator may calculate the gamma compensation value based on the first brightness characteristic value in a first case where the desired correction gray level is included in the first unit interval, and calculate the gamma compensation value based on the first brightness characteristic value and the second brightness characteristic value in a second case where the desired correction gray level is included in the second unit interval.

[0031] In an embodiment, the brightness compensation device may further include a reference image data supplier, which supplies first reference image data, second reference image data and third reference image data to the display panel.

[0032] In one embodiment, the display panel may include multiple pixels, and the grayscale compensation calculator may calculate the grayscale compensation for each of the multiple pixels.

[0033] In an embodiment, the display panel may include multiple unit blocks, and each of the multiple unit blocks may include multiple pixels, and the grayscale compensation calculator may calculate the grayscale compensation for each of the multiple unit blocks.

[0034] A method for compensating brightness according to embodiments of the present disclosure may include: providing a display panel with first reference image data, second reference image data, and third reference image data corresponding to a first reference gray level, a second reference gray level, and a third reference gray level; generating first captured image data, second captured image data, and third captured image data by capturing a first reference gray level image, a second reference gray level image, and a third reference gray level image displayed on the display panel based on the first reference image data, the second reference image data, and the third reference image data; calculating a first brightness characteristic value corresponding to a first unit interval between the first reference gray level and the second reference gray level, and a second brightness characteristic value corresponding to a second unit interval between the second reference gray level and the third reference gray level, based on the first captured image data, the second captured image data, and the third captured image data; calculating a desired correction gray level corresponding to the first reference gray level based on the first captured image data, the second captured image data, and the third captured image data; and calculating a compensation gray level corresponding to the first reference gray level based on a gamma compensation value and a desired correction gray level. Calculating the compensated gray level may include: in a first case where the desired corrected gray level is included in a first unit interval, calculating a gamma compensation value based on a first luminance characteristic value; and in a second case where the desired corrected gray level is included in a second unit interval, calculating a gamma compensation value based on a first luminance characteristic value and a second luminance characteristic value.

[0035] In an embodiment, in the second case, the gamma compensation value can be calculated using the following seventh equation:

[0036]

[0037] Wherein, γt can represent the gamma compensation value, γ1 can represent the first luminance characteristic value, γ2 can represent the second luminance characteristic value, g1 can represent the first reference gray level, g2 can represent the second reference gray level, and gt can represent the desired correction gray level.

[0038] In an embodiment, the first captured image data may include a first brightness value displayed on a display panel corresponding to a first reference gray level.

[0039] In an embodiment, calculating the desired correction gray level may include: calculating a brightness compensation rate based on the difference between a first brightness value and a first brightness target value corresponding to a first reference gray level; and calculating the desired correction gray level based on the brightness compensation rate. Attached Figure Description

[0040] The accompanying drawings, which are included to provide a further understanding of the inventive concept and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the inventive concept of this disclosure and, together with the description, serve to explain the principles of the inventive concept of this disclosure.

[0041] Figure 1 This is a block diagram illustrating a display system including a brightness compensation device according to an embodiment of the present disclosure.

[0042] Figure 2 This is a block diagram illustrating an example of a display device including memory, by Figure 1 The compensated gray levels generated by the brightness compensation device are stored in this memory.

[0043] Figure 3 It is shown Figure 2 A circuit diagram of an example of pixels included in a display device.

[0044] Figure 4 , Figure 5 , Figure 6 and Figure 7 It is used for explanation Figure 1 A diagram illustrating an example of the operation of a brightness compensation device.

[0045] Figure 8A and Figure 8B It is used for calculation Figure 1 An example table of brightness characteristic values ​​for a brightness compensation device.

[0046] Figure 9 This is a flowchart illustrating a method for compensating brightness according to an embodiment of the present disclosure. Detailed Implementation

[0047] Because this disclosure allows for various changes and numerous embodiments, specific embodiments will be shown in the accompanying drawings and described in detail in the written description. However, this is not intended to limit this disclosure to a particular mode of practice, and it will be understood that all changes, equivalents, and alternatives that do not depart from the spirit and scope of this disclosure are covered herein.

[0048] In the accompanying drawings, similar reference numerals denote similar elements. For clarity of this disclosure, the dimensions of elements may be shown as larger than their actual dimensions in the drawings. It will be understood that although the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. Rather, these terms are used to distinguish one element from another. For example, a first element discussed below may be referred to as a second element without departing from the scope of this disclosure. Similarly, a second element may also be referred to as a first element. In this disclosure, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise.

[0049] It will be further understood that the terms “comprise,” “include,” “have,” etc., as used in this disclosure indicate the presence of the stated features, integers, steps, operations, elements, components, and / or any combination thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0050] Furthermore, the statement that a component is "coupled" to another component includes not only the case where the component is directly coupled to another component, but also the case where other components are coupled between them.

[0051] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0052] Figure 1 This is a block diagram illustrating a display system including a brightness compensation device according to an embodiment of the present disclosure. Figure 2 This is a block diagram illustrating an example of a display device 100 including a memory 150, by Figure 1 The compensated gray level generated by the brightness compensation device is stored in the memory 150. Figure 3 It is shown Figure 2 A circuit diagram of an example of pixels included in the display device 100.

[0053] Reference Figure 1 The display system 1000 includes a display panel 110, an imaging unit 200, a brightness compensation device 300, and a memory 150. The brightness compensation device 300 supplies reference image data (RID) to the display panel 110, and the imaging unit 200 captures an image displayed on the display panel 110 based on the reference image data (RID) and generates captured image data (CID). The brightness compensation device 300 receives the captured image data (CID) from the imaging unit 200 and performs brightness compensation on the display panel 110 using the captured image data (CID).

[0054] In the following text, a display device 100 including a display panel 110 will be described, and a brightness compensation device 300 configured according to the display device and a display system 1000 including the brightness compensation device 300 will be described thereafter. Figure 2 and Figure 3 This can be used as a reference to describe a display device including display panel 110.

[0055] Reference Figure 1 and Figure 2 The display device 100 may include a display panel 110, a timing controller 120, a scan driver 130, a data driver 140, a memory 150, and a compensator 160.

[0056] The display panel 110 may include multiple scan lines SL1 to SLn, multiple data lines DL1 to DLm, and multiple pixels PX.

[0057] Each pixel PX can be connected to at least one of scan lines SL1 to SLn and at least one of data lines DL1 to DLm. Simultaneously, the pixel PX can receive voltages from a first power supply VDD and a second power supply VSS externally. Here, the first power supply VDD and the second power supply VSS can be voltages required for the operation of the pixel PX. For example, the first power supply VDD can have a voltage level higher than that of the second power supply VSS.

[0058] Reference Figure 3 A pixel PX may include a light-emitting element LD and a driving circuit DC connected to the light-emitting element LD to drive the light-emitting element LD.

[0059] The first electrode (e.g., anode) of the light-emitting element LD can be connected to a first power supply VDD via a driving circuit DC, and the second electrode (e.g., cathode) of the light-emitting element LD can be connected to a second power supply VSS. The light-emitting element LD can emit light with a brightness corresponding to the amount of driving current controlled by the driving circuit DC.

[0060] Light-emitting elements (LDs) can include organic light-emitting diodes (OLEDs). Alternatively, LDs can include inorganic light-emitting diodes such as micro light-emitting diodes (LEDs) or quantum dot light-emitting diodes. Furthermore, LDs can be components comprising both organic and inorganic materials. Figure 3 In this embodiment, a pixel PX includes a single light-emitting element LD. However, in another embodiment, a pixel PX may include multiple light-emitting elements. The multiple light-emitting elements may be connected in series, in parallel, or in a series-parallel connection.

[0061] The first power supply VDD and the second power supply VSS can have different potentials. For example, the voltage applied through the first power supply VDD can be greater than the voltage applied through the second power supply VSS.

[0062] The driving circuit DC may include a first transistor T1, a second transistor T2, and a storage capacitor Cst.

[0063] The first electrode of the first transistor T1 (also referred to herein as the driving transistor) may be connected to a first power supply VDD, and the second electrode of the first transistor T1 may be electrically connected to the first electrode (or anode) of the light-emitting element LD. The gate electrode of the first transistor T1 may be connected to a first node N1. The first transistor T1 may control the amount of driving current supplied to the light-emitting element LD in response to the data voltage Vdata supplied to the first node N1 via the data line DL.

[0064] The first electrode of the second transistor T2 (also referred to herein as the switching transistor) can be connected to the data line DL, and the second electrode of the second transistor T2 can be connected to the first node N1. The gate electrode of the second transistor T2 can be connected to the scan line SL.

[0065] When a scan signal with a voltage (e.g., a gate turn-on voltage) is supplied from the scan line SL, the second transistor T2 is turned on to electrically connect the data line DL and the first node N1. At this time, the data voltage Vdata corresponding to the frame is supplied to the data line DL, and therefore, the data voltage Vdata can be transmitted to the first node N1. The data voltage Vdata transmitted to the first node N1 can be stored in the storage capacitor Cst.

[0066] One electrode of the storage capacitor Cst can be connected to the first node N1, and the other electrode of the storage capacitor Cst can be connected to the first electrode (or anode) of the light-emitting element LD. The storage capacitor Cst can be charged with the data voltage Vdata supplied to the first node N1, and this charging voltage can be maintained until the data voltage Vdata of the next frame is supplied.

[0067] For ease of description, Figure 3 A pixel PX with a relatively simple structure is shown. Various modifications can be made to the structure of the driving circuit DC without departing from the scope of this disclosure. For example, the driving circuit DC may include various transistors, such as a compensation transistor for compensating the threshold voltage of the first transistor T1, an initialization transistor for initializing the first node N1, and / or a light-emitting control transistor for controlling the light-emitting time of the light-emitting element LD. Additionally, the driving circuit DC may also include more than one storage capacitor and / or other circuit elements, such as a boost capacitor for boosting the voltage of the first node N1.

[0068] exist Figure 3 In the diagram, the first transistor T1 and the second transistor T2 are shown as N-type transistors, but this disclosure is not limited thereto. That is, at least one of the first transistor T1 and the second transistor T2 included in the drive circuit DC may be changed to a P-type transistor.

[0069] The pixels PX included in the display panel 110 can control the amount of driving current supplied to the light-emitting element LD according to the data voltage Vdata, and the light-emitting element LD can emit light according to the amount of driving current to display an image.

[0070] In theory, display panels 110 manufactured using the same process are expected to have the same brightness characteristics. However, in reality, due to variations in the manufacturing process, display panels 110 may not exhibit the same brightness characteristics. Furthermore, the brightness characteristics of a pixel PX may differ between the pixel PX during design and after the manufacturing process is complete. These variations in brightness characteristics may be different for each pixel in the display panel 110, or even for each pixel PX included in the same display panel 110.

[0071] Due to variations in brightness characteristics, even when the same data voltage Vdata is supplied to pixel PX, brightness differences may exist between pixels PX. For example, such variations include, but are not limited to, variations in the threshold voltage and channel mobility of the first transistor T1 (driving transistor) included in each pixel PX. This can cause image distortion such as the Mura effect on the display panel 110. Therefore, brightness compensation processing can be performed to compensate for this image distortion before the display panel 110 is shipped to the customer.

[0072] Return to reference Figure 2 The timing controller 120 may receive control signals from an external source (e.g., a graphics processor) and compensated image data CGD from the compensator 160. The timing controller 120 may generate a scan control signal SCS and a data control signal DCS based on the control signals, and convert the compensated image data CGD to generate a data signal DATA. Examples of control signals may include, but are not limited to, vertical synchronization signals, horizontal synchronization signals, and clock signals.

[0073] The scan driver 130 can generate scan signals based on scan control signals SCS provided from the timing controller 120. Examples of scan control signals SCS may include, but are not limited to, scan start signals and scan clock signals. The scan driver 130 can sequentially provide scan signals with on-level pulses to scan lines SL1 to SLn.

[0074] Data driver 140 can generate a data voltage Vdata based on a data signal DATA and a data control signal DCS received from timing controller 120, and provide the data voltage Vdata to data lines DL1 to DLm. Data driver 140 can also generate an analog data voltage Vdata based on a digital data signal DATA. For example, data driver 140 can sample grayscale values ​​included in the data signal DATA and provide the data voltage Vdata corresponding to the grayscale values ​​to data lines DL1 to DLm on a pixel-row basis. Examples of data control signals DCS include, but are not limited to, data clock signals and data enable signals.

[0075] The memory 150 can store the compensated grayscale level GCV, and the compensated grayscale level GCV can be used to compensate for distortion of the image displayed on the display panel 110 that may be caused by brightness deviations of pixels PX. The compensated grayscale level GCV can be generated by... Figure 1 The brightness compensation device 300 or display system 1000 is generated.

[0076] A compensated grayscale GCV can be generated for each pixel PX. Alternatively, a compensated grayscale GCV can be generated for each cell block comprising a predetermined number of pixels PX. For the sake of convenience, it is assumed in the following description that a compensated grayscale GCV is generated for each pixel PX.

[0077] The memory 150 may be implemented as a separate component within the display device 100. However, this is an example, and the present disclosure is not limited thereto. In another embodiment, the memory 150 may be implemented as embedded in the timing controller 120 or the data driver 140.

[0078] The compensator 160 can receive input image data from an external source (e.g., a graphics processor) and receive the compensated grayscale level GCV stored in memory 150. The compensator 160 can generate compensated image data CGD by correcting the input image data based on the compensated grayscale level GCV, and supply the compensated image data CGD to the timing controller 120. Meanwhile, in Figure 2 In this illustration, timing controller 120 and compensator 160 are shown as separate components. However, this is a convenient example for explanation, and timing controller 120 and compensator 160 can be configured as a single unit. For example, compensator 160 can be implemented as embedded within timing controller 120.

[0079] Based on the compensated image data CGD generated based on the compensated grayscale level GCV, the brightness of the pixels PX included in the display panel 110 can be corrected so that distortion in the image displayed on the display panel 110 can be compensated. The specific configuration of the brightness compensation device 300 that generates the compensated grayscale level GCV and the display system 1000 including the brightness compensation device 300 will be described below.

[0080] The display panel 110 can receive reference image data RID from the brightness compensation device 300. Based on the reference image data RID, a data voltage Vdata can be applied to the pixels PX included in the display panel 110 to display an image. At this time, as referenced... Figure 2 and Figure 3 As described, due to variations in the manufacturing process, there may be deviations in the brightness characteristics for each pixel PX.

[0081] Imaging unit 200 can capture images displayed on display panel 110 and generate captured image data CID. For example, imaging unit 200 can be a two-dimensional charge-coupled device (CCD) camera, such as a zone scan camera and a frame camera. Here, captured image data CID can include brightness information of the image displayed on display panel 110. Imaging unit 200 can supply captured image data CID to brightness compensation device 300.

[0082] The brightness compensation device 300 can supply reference image data RID to the display panel 110, receive captured image data CID corresponding to the image displayed on the display panel 110, and generate compensated grayscale level GCV based on the captured image data CID.

[0083] In an embodiment, the brightness compensation device 300 may include a reference image data supplier 310, a unit image generator 320, a brightness characteristic value calculator 330, a desired correction gray level calculator 340, and a compensation gray level calculator 350.

[0084] The reference image data supplier 310 can sequentially supply K reference image data RIDs (or first reference image data to the Kth reference image data) corresponding to K reference gray levels (where K is a natural number of 2 or greater) to the display panel 110. Accordingly, the display panel 110 can sequentially display K reference gray level images (or first reference gray level images to the Kth reference gray level images) based on the K reference image data RIDs. The imaging unit 200 can generate K captured image data CIDs (or first captured image data to the Kth captured image data) by capturing the K reference gray level images sequentially displayed on the display panel 110. Here, the K captured image data CIDs can each include brightness information of the K reference gray level images. The brightness information can include a brightness value measured for each pixel PX included in the display panel 110.

[0085] According to an embodiment, the K reference gray levels may include six reference gray levels sampled for gray levels 0 to 255. In this case, the six reference gray levels may include 32 gray levels, 64 gray levels, 96 gray levels, 128 gray levels, 196 gray levels, and 224 gray levels. However, this is just an example, and the reference gray levels are not limited to this. The K reference gray levels can be set in various ways. For example, the K reference gray levels may include ten reference gray levels sampled for gray levels 0 to 255.

[0086] The unit image generator 320 can generate K unit images based on K captured image data CIDs. Here, each of the K unit images can include information about the brightness value measured for each pixel PX against the corresponding reference grayscale image.

[0087] At the same time, as referenced Figure 2 As described, when generating a compensated grayscale level GCV for each unit block comprising a predetermined number of pixels PX, the unit image generator 320 can generate a unit image including information about the luminance values ​​measured for each unit block against the corresponding reference grayscale image. The luminance values ​​measured for each unit block can be determined by the average luminance value of the pixels PX included in each unit block. However, this is an example, and the luminance values ​​measured for each unit block can be determined by the maximum or minimum luminance value among the pixels PX included in each unit block, or by the luminance value of a specific pixel PX among the pixels PX included in the corresponding unit block.

[0088] For each pixel PX included in each of the K unit images, the luminance characteristic value calculator 330 can calculate a luminance characteristic value based on the luminance value measured corresponding to each of the K reference gray levels. In an embodiment, the luminance characteristic value calculator 330 can calculate K-1 luminance characteristic values ​​in response to the K reference gray levels. For example, the K reference gray levels can calculate K-1 luminance characteristic values ​​corresponding to an interval (hereinafter referred to as a "unit interval") between two adjacent reference gray levels. For example, the interval between a first reference gray level among the K reference gray levels and a second reference gray level greater than the first reference gray level can be defined as a first unit interval, and the interval between a second reference gray level among the K reference gray levels and a third reference gray level greater than the second reference gray level can be defined as a second unit interval. Similarly, the interval between a third reference gray level among the K reference gray levels and a fourth reference gray level greater than the third reference gray level can be defined as a third unit interval.

[0089] In this embodiment, the luminance characteristic value calculator 330 can calculate the luminance characteristic value corresponding to each of the K-1 unit intervals. For example, for each pixel PX, the luminance characteristic value calculator 330 can calculate the luminance characteristic value corresponding to the first unit interval using a first unit image (an image displayed via a first reference grayscale level) and a second unit image (an image displayed via a second reference grayscale level) among the K unit images. Similarly, for each pixel PX, the luminance characteristic value calculator 330 can calculate the luminance characteristic value corresponding to the second unit interval among the K-1 unit intervals using a second unit image and a third unit image (an image displayed via a third reference grayscale level) among the K unit images.

[0090] Reference Figures 4 to 7 This document describes in detail the configuration of the luminance characteristic value calculator 330, which is used to calculate luminance characteristic values ​​and luminance characteristic values ​​per unit interval.

[0091] The expected gray level correction calculator 340 can receive K unit images from the unit image generator 320. The expected gray level correction calculator 340 can determine the brightness value of pixel PX corresponding to the reference gray level based on the K unit images.

[0092] Simultaneously, for each pixel PX, a target brightness value corresponding to each of the K reference gray levels can be pre-stored in the desired gray level calculator 340. Here, the target brightness value can correspond to the brightness characteristics designed in the display panel 110 in response to the corresponding reference gray level, that is, the brightness value of the light emitted by the pixel PX in response to the corresponding reference gray level according to the design specifications of the display panel 110.

[0093] For each pixel PX, the desired correction gray level can be calculated for each of the K reference gray levels. The desired correction gray level calculator 340 can calculate the desired correction gray level corresponding to the corresponding reference gray level based on the difference between the luminance value measured corresponding to a reference gray level and the luminance target value of the corresponding reference gray level.

[0094] In this embodiment, the desired grayscale level calculator 340 can calculate a brightness compensation rate for each pixel PX based on the difference between the brightness value measured corresponding to each of the K reference grayscale levels and the target brightness value, and calculate the desired grayscale level using the brightness compensation rate and a representative gamma value through inverse gamma correction. Here, the representative gamma value can be a preset brightness characteristic value. For example, the representative gamma value can be 2.2, which is the standard gamma value of the National Television System Committee (NTSC). The brightness compensation device 300 can determine the brightness characteristic value reflected when calculating the gamma compensation value based on a unit interval including the desired grayscale level corresponding to each of the K reference grayscale levels. (See reference...) Figures 4 to 7 This document describes in detail the configuration of the Expected Corrected Gray Level Calculator 340 used to calculate the expected corrected gray level.

[0095] The compensation gray level calculator 350 can calculate the compensation gray level GCV for each pixel PX based on the luminance characteristic value calculated by the luminance characteristic value calculator 330 and the desired correction gray level calculated by the desired correction gray level calculator 340. For example, the compensation gray level calculator 350 can calculate the gamma compensation value corresponding to each of the K reference gray levels based on the luminance characteristic value and the desired correction gray level, and calculate the compensation gray level GCV corresponding to each of the K reference gray levels based on the gamma compensation value.

[0096] In an embodiment, the grayscale compensation calculator 350 can calculate the gamma compensation value based on a unit interval that includes the desired correction grayscale level. That is, when the desired correction grayscale level is outside a unit interval that includes a reference grayscale level, the grayscale compensation calculator 350 can calculate the gamma compensation value by reflecting all luminance characteristic values ​​corresponding to the unit interval between the reference grayscale level and the desired correction grayscale level. For example, if the desired correction grayscale level corresponding to a first reference grayscale level included in a first unit interval among K reference grayscale levels is included in the first unit interval, the grayscale compensation calculator 350 can calculate a first luminance characteristic value corresponding to the first unit interval as the gamma compensation value. In another example, if the desired correction grayscale level corresponding to a first reference grayscale level included in a first unit interval among K reference grayscale levels is included in a second unit interval, the grayscale compensation calculator 350 can calculate the gamma compensation value based on the first luminance characteristic value corresponding to the first unit interval and the second luminance characteristic value corresponding to the second unit interval. In another example, if the desired correction gray level corresponding to the first reference gray level included in the first unit interval among the K reference gray levels is included in the third unit interval, the compensation gray level calculator 350 can calculate the gamma compensation value based on the first luminance characteristic value corresponding to the first unit interval, the second luminance characteristic value corresponding to the second unit interval, and the third luminance characteristic value corresponding to the third unit interval.

[0097] In this embodiment, the compensation gray level calculator 350 calculates the gamma compensation value based on the sign of the brightness compensation rate. A positive brightness compensation rate indicates that the brightness value measured corresponding to a reference gray level is less than the target brightness value corresponding to the corresponding reference gray level. Conversely, a negative brightness compensation rate indicates that the brightness value measured corresponding to a reference gray level is greater than the target brightness value corresponding to the corresponding reference gray level. If the brightness compensation rate calculated by the desired correction gray level calculator 340 has a negative value, for example, when the desired correction gray level corresponding to the first reference gray level is included in the fourth unit interval, the compensation gray level calculator 350 can calculate the gamma compensation value based on the fourth brightness characteristic value corresponding to the fourth unit interval.

[0098] In an embodiment, for each of the K reference gray levels, the compensation gray level calculator 350 can use the gamma compensation value and the brightness compensation rate calculated by the desired correction gray level calculator 340 to calculate the compensation gray level GCV through inverse gamma correction.

[0099] In another embodiment, the compensated gray level calculator 350 can calculate the compensated gray level GCV corresponding to the entire gray level region by applying linear interpolation and / or linear extrapolation to the compensated gray level GCV corresponding to the K reference gray levels.

[0100] Reference Figures 4 to 7 This document describes in detail the configuration of the Compensated Gray Level Calculator 350 for calculating gamma compensation values ​​and the configuration for calculating the Compensated Gray Level GCV.

[0101] The memory 150 can receive and store the compensated gray level GCV calculated by the compensated gray level calculator 350. The memory 150 can store the compensated gray level GCV corresponding to the entire gray level region for each pixel PX. Here, the memory 150 can be as described with reference to... Figure 1 and Figure 2 Configure as described.

[0102] Figures 4 to 7 It is used for explanation Figure 1 A diagram illustrating an example of the operation of the brightness compensation device 300. Figures 4 to 7 In this example, the K reference gray levels will include six reference gray levels (e.g., 32, 64, 96, 128, 196, and 224 gray levels) sampled for gray levels 0 to 255. Among these six reference gray levels, 96 gray level can be defined as the first reference gray level g1, 128 gray level as the second reference gray level g2, 196 gray level as the third reference gray level g3, 224 gray level as the fourth reference gray level g4, ​​and 64 gray level as the fifth reference gray level g5. Furthermore, the first unit interval SU1 can be defined as corresponding to the interval from 96 gray levels to 127 gray levels (i.e., from the first reference gray level g1 to the second reference gray level g2), the second unit interval SU2 can be defined as corresponding to the interval from 128 gray levels to 195 gray levels (i.e., from the second reference gray level g2 to the third reference gray level g3), the third unit interval SU3 can be defined as corresponding to the interval from 196 gray levels to 223 gray levels (i.e., from the third reference gray level g3 to the fourth reference gray level g4), and the fourth unit interval SU4 can be defined as corresponding to the interval from 64 gray levels to 95 gray levels (i.e., from the fifth reference gray level g5 to the first reference gray level g1). Meanwhile, for the sake of convenience, in Figures 4 to 7 In the middle, it will target a pixel PX (for example, Figure 2 The operation of the brightness compensation device 300 is illustrated using pixels (PX) as an example. The configuration used to calculate the compensated gray level GCV for the first reference gray level g1 will be described in detail.

[0103] Reference Figure 1 and Figures 4 to 7 The luminance characteristic value calculator 330 can calculate the corresponding luminance characteristic value for each unit interval (e.g., the first unit interval SU1 to the fourth unit interval SU4), such as the first luminance characteristic value γ1 to the fourth luminance characteristic value γ4.

[0104] Corresponding to the first unit interval SU1, the luminance characteristic value calculator 330 can use the first luminance value measured in response to the first reference gray level g1 and the second luminance value measured in response to the second reference gray level g2 to calculate the first luminance characteristic value γ1 corresponding to the first unit interval SU1.

[0105] Similarly, corresponding to the second unit interval SU2, the luminance characteristic value calculator 330 can use the second luminance value measured in response to the second reference gray level g2 and the third luminance value measured in response to the third reference gray level g3 to calculate the second luminance characteristic value γ2 corresponding to the second unit interval SU2.

[0106] Similarly, corresponding to the third unit interval SU3, the luminance characteristic value calculator 330 can use the third luminance value measured in response to the third reference gray level g3 and the fourth luminance value measured in response to the fourth reference gray level g4 to calculate the third luminance characteristic value γ3 corresponding to the third unit interval SU3.

[0107] Similarly, corresponding to the fourth unit interval SU4, the luminance characteristic value calculator 330 can use the fifth luminance value measured in response to the fifth reference gray level g5 and the first luminance value measured in response to the first reference gray level g1 to calculate the fourth luminance characteristic value γ4 corresponding to the fourth unit interval SU4.

[0108] In this embodiment, the first luminance characteristic value γ1 to the fourth luminance characteristic value γ4 can be calculated according to the gamma correction formula using the following Equation 1.

[0109] [Equation 1]

[0110]

[0111]

[0112] Here, γ1 to γ4 represent the first to fourth luminance characteristic values, L1 to L5 represent the first to fifth luminance values ​​measured, and g1 to g5 represent the first to fifth reference gray levels.

[0113] Reference Figures 1 to 4 This explains the exemplary case where the expected correction gray level (or the first expected correction gray level gt1) corresponding to the first reference gray level g1 included in the first unit interval SU1 among the K reference gray levels (i.e., 6 reference gray levels) is included in the first unit interval SU1.

[0114] Reference Figure 1 and Figure 4The grayscale calculator 340 is expected to calculate the brightness compensation rate based on the difference between the first brightness value L1 measured in response to the first reference grayscale level g1 and the target brightness value of the first reference grayscale level g1. In this case, the brightness compensation rate can be calculated using the following Equation 2.

[0115] [Equation 2]

[0116]

[0117] Here, LCR represents the luminance compensation rate, LT represents the target luminance value, and L1 represents the first luminance value L1. Meanwhile, in Figure 4 In this context, we assume that the target brightness value LT is the first target brightness value Lt1.

[0118] After obtaining the luminance compensation rate (LCR) from Equation 2, the desired correction gray level calculator 340 of the luminance compensation device 300 can use the following Equation 3 to calculate the desired correction gray level (or the first desired correction gray level gt1) to determine the luminance characteristic value to be reflected when calculating the gamma compensation value corresponding to the first reference gray level g1. That is, the luminance compensation device 300 can determine the luminance characteristic value to be reflected when calculating the gamma compensation value by predicting a unit interval including the correction gray level corresponding to the first reference gray level g1 using a unit interval including the desired correction gray level. For this purpose, based on the calculated luminance compensation rate (LCR) and the representative gamma value, the desired correction gray level calculator 340 can use the representative gamma value to calculate the first desired correction gray level gt1 by inverse gamma correction for the luminance compensation rate (LCR). Here, the representative gamma value can be 2.2, which is the standard gamma value for NTSC.

[0119] Accordingly, the first desired corrected gray level gt1 can be calculated using the following Equation 3.

[0120] [Equation 3]

[0121]

[0122] Here, gt1 represents the first desired gray level to be corrected, g1 represents the first reference gray level, and LCR represents the luminance compensation rate.

[0123] The gray-level compensation calculator 350 can calculate a gamma compensation value based on a unit interval including a first desired gray-level gt1 calculated by the desired gray-level compensation calculator 340. In this example, the first desired gray-level gt1 is included in the first unit interval SU1, so the gray-level compensation calculator 350 can calculate a first luminance characteristic value γ1 corresponding to the first unit interval SU1 as the gamma compensation value.

[0124] Accordingly, based on the gamma compensation value and the luminance compensation rate, as shown in Equation 4 below, the compensated gray level calculator 350 can use the gamma compensation value to calculate the compensated gray level GCV through inverse gamma correction for the luminance compensation rate.

[0125] [Equation 4]

[0126]

[0127] Here, gcv represents the compensated gray level GCV, g1 represents the first reference gray level, LCR represents the luminance compensation rate, and γt represents the gamma compensation value. Figure 4 In this example, the gamma compensation value γt can be the same as the first luminance characteristic value γ1 as described above.

[0128] For reference Figure 1 and Figure 4 As described, when the first desired correction gray level gt1, corresponding to the first reference gray level g1 included in the first unit interval SU1 among K reference gray levels, is included in the first unit interval SU1, the brightness compensation device 300 can use the first brightness characteristic value γ1 corresponding to the first unit interval SU1 to calculate the gamma compensation value γt. Since the first desired correction gray level gt1 is included in the first unit interval SU1 corresponding to the first reference gray level g1, the brightness compensation device 300 only uses the first brightness characteristic value γ1 to calculate the gamma compensation value γt, and the brightness compensation device 300 can calculate the compensation gray level GCV relatively accurately. In addition, due to the simple calculation, the configuration for calculating the compensation gray level GCV of the brightness compensation device 300 can be simplified.

[0129] At the same time, as referenced Figure 1 As described, the compensated gray level calculator 350 can calculate the compensated gray level GCV corresponding to the entire gray level area by applying linear interpolation and / or linear extrapolation to the compensated gray level GCV corresponding to K reference gray levels.

[0130] For example, the brightness compensation device 300 can calculate the compensated gray level GCV from gray level 0 to gray level 31 by applying linear interpolation and / or linear extrapolation to the compensated gray level GCV of 32 gray levels.

[0131] In addition, the brightness compensation device 300 can calculate the compensation gray level GCV for gray levels 33 to 63 by applying linear interpolation and / or linear extrapolation to the compensation gray level GCV for gray levels 32 and 64.

[0132] In addition, the brightness compensation device 300 can calculate the compensation gray level GCV for gray levels 65 to 95 by applying linear interpolation and / or linear extrapolation to the compensation gray level GCV for gray levels 64 and 96.

[0133] In addition, the brightness compensation device 300 can calculate the compensation gray level GCV for gray levels 97 to 127 by applying linear interpolation and / or linear extrapolation to the compensation gray level GCV for gray levels 96 and 128.

[0134] In addition, the brightness compensation device 300 can calculate the compensation gray level GCVs of gray levels 129 to 195 by applying linear interpolation and / or linear extrapolation to the compensation gray level GCVs of gray levels 128 and 196.

[0135] In addition, the brightness compensation device 300 can calculate the compensation gray level GCVs of gray levels 197 to 223 by applying linear interpolation and / or linear extrapolation to the compensation gray level GCVs of gray levels 196 and 224.

[0136] In addition, the brightness compensation device 300 can calculate the compensation gray level GCV for gray levels 225 to 255 by applying linear interpolation to the compensation gray level GCV for gray level 224.

[0137] In this way, the brightness compensation device 300 can calculate the compensated gray level GCV corresponding to the entire gray level area by using a portion of the gray levels (e.g., 6 reference gray levels).

[0138] Next, we will refer to Figure 1 and Figure 5 This explains another exemplary case where the desired corrected gray level (or the second desired corrected gray level gt2) corresponding to the first reference gray level g1 included in the first unit interval SU1 among the K reference gray levels (i.e., 6 reference gray levels) is included in the second unit interval SU2. Meanwhile, in Figure 5 In this context, we assume that the target brightness value LT is the second target brightness value Lt2.

[0139] Reference Figure 1 and Figure 5 The expected correction gray level calculator 340 can calculate the second expected correction gray level gt2 based on the calculated brightness compensation rate and representative gamma value through inverse gamma correction. Here, the second expected correction gray level gt2 can be calculated using the following equation 5, which is consistent with the reference equation 340. Figure 4 The description of Equation 3 is basically similar.

[0140] [Equation 5]

[0141]

[0142] Here, gt2 represents the second desired gray level, g2 represents the second reference gray level, and LCR represents the luminance compensation rate.

[0143] The gray-level compensation calculator 350 can calculate the gamma compensation value based on a unit interval including the second desired gray-level gt2 calculated by the desired gray-level compensation calculator 340. In this example, the second desired gray-level gt2 is included in the second unit interval SU2, so the gray-level compensation calculator 350 can calculate the gamma compensation value based on the first luminance characteristic value γ1 corresponding to the first unit interval SU1 and the second luminance characteristic value γ2 corresponding to the second unit interval SU2. That is, when the desired gray-level (or the second desired gray-level gt2) is outside the unit interval (or the first unit interval SU1) including the reference gray-level (or the first reference gray-level g1), the gray-level compensation calculator 350 can use all luminance characteristic values ​​(i.e., the first luminance characteristic value γ1 and the second luminance characteristic value γ2) corresponding to the unit interval (i.e., the first unit interval SU1 and the second unit interval SU2) between the reference gray-level (or the first reference gray-level g1) and the desired gray-level (or the second desired gray-level gt2) to calculate the gamma compensation value.

[0144] Specifically, to calculate the gamma compensation value reflecting the brightness characteristics of each unit interval, equations 6 and 7 can be used. Equation 6, used to calculate the second brightness value L2, reflects the first brightness characteristic value γ1 corresponding to the first unit interval SU1 between the first reference gray level g1 and the second reference gray level g2, and equation 7, used to calculate the second brightness target value, reflects the second brightness characteristic value γ2 corresponding to the second unit interval SU2 between the second reference gray level g2 and the second desired correction gray level gt2. Furthermore, equation 9, used to calculate the gamma compensation value γt, can be obtained by combining equation 8 with equation 7 according to the gamma correction formula. Accordingly, the compensation gray level calculator 350 can calculate the gamma compensation value based on equation 9, which reflects all brightness characteristic values ​​corresponding to the unit interval between the first reference gray level g1 and the second desired correction gray level gt2.

[0145] [Equation 6]

[0146]

[0147] Here, γ1 represents the first brightness characteristic value, L1 and L2 represent the first brightness value and the second brightness value, and g1 and g2 represent the first reference gray level and the second reference gray level.

[0148] [Equation 7]

[0149]

[0150] Here, Lt2 represents the second target brightness value, γ1 and γ2 represent the first brightness characteristic value and the second brightness characteristic value, L1 and L2 represent the first brightness value and the second brightness value, g1 and g2 represent the first reference gray level and the second reference gray level, and gt2 represents the second desired correction gray level.

[0151] [Equation 8]

[0152]

[0153] Here, Lt2 represents the second target brightness value, γt represents the gamma compensation value, L1 represents the first brightness value, g1 represents the first reference gray level, and gt2 represents the second desired correction gray level.

[0154] [Equation 9]

[0155]

[0156] Here, γt represents the gamma compensation value, γ1 and γ2 represent the first luminance characteristic value and the second luminance characteristic value, g1 and g2 represent the first reference gray level and the second reference gray level, and gt2 represents the second desired correction gray level.

[0157] For reference Figure 1 and Figure 4 As described, when the desired gray level to be corrected is included in a unit interval including the reference gray level, the compensated gray level calculator 350 can use the gamma compensation value and the luminance compensation rate to calculate the compensated gray level GCV through inverse gamma correction.

[0158] For reference Figure 1 and Figure 5 As described, when the desired grayscale level to be corrected is outside a unit interval including the reference grayscale level, the brightness compensation device 300 can calculate the gamma compensation value by reflecting all brightness characteristic values ​​corresponding to the unit interval between the reference grayscale level and the desired grayscale level. Accordingly, the brightness compensation device 300 can accurately calculate the gamma compensation value used to calculate the GCV of the compensated grayscale level. Therefore, the display quality of the display panel 110 can be improved by effectively and accurately compensating for uneven brightness in the display.

[0159] Although Figure 5An example is shown where the desired gray level to be corrected is outside a unit interval including a reference gray level, and a second desired gray level gt2 corresponding to the first reference gray level g1 is included in a second unit interval SU2. The luminance compensation device 300 calculates a gamma compensation value based on two luminance characteristic values ​​(i.e., a first luminance characteristic value γ1 and a second luminance characteristic value γ2) corresponding to the two unit intervals (i.e., the first unit interval SU1 and the second unit interval SU2). However, this disclosure is not limited thereto. In another embodiment, based on a unit interval including the desired gray level, the luminance compensation device 300 can calculate a gamma compensation value by reflecting three or more luminance characteristic values.

[0160] Reference Figure 1 and Figure 6 The desired correction gray level (or the third desired correction gray level gt3) corresponding to the first reference gray level g1 included in the first unit interval SU1 is included in the third unit interval SU3. Accordingly, the desired correction gray level calculator 340 can calculate the brightness compensation rate based on the difference between the first brightness value L1 measured in response to the first reference gray level g1 and the brightness target value LT (or the third brightness target value Lt3), and use the brightness compensation rate and the representative gamma value to calculate the third desired correction gray level gt3.

[0161] Furthermore, since the third desired correction gray level gt3 is included in the third unit interval SU3, the compensation gray level calculator 350 can calculate the gamma compensation value based on the first luminance characteristic value γ1, the second luminance characteristic value γ2, and the third luminance characteristic value γ3. That is, in order to calculate the gamma compensation value reflecting the luminance characteristics of each unit interval, the compensation gray level calculator 350 can calculate the gamma compensation value based on the following equation 10, which reflects all luminance characteristic values ​​(i.e., the first luminance characteristic value γ1, the second luminance characteristic value γ2, and the third luminance characteristic value γ3) corresponding to the unit interval between the first reference gray level g1 and the third desired correction gray level gt3.

[0162] [Equation 10]

[0163]

[0164] Here, γt represents the gamma compensation value, γ1, γ2 and γ3 represent the first luminance characteristic value to the third luminance characteristic value, g1, g2 and g3 represent the first reference gray level to the third reference gray level, and gt3 represents the third desired correction gray level.

[0165] As referenced above Figures 1 to 6As described, based on a unit interval including the desired grayscale level to be corrected, the brightness compensation device 300 can accurately calculate the gamma compensation value used to calculate the GCV of the compensated grayscale level by reflecting three or more brightness characteristic values. Therefore, the display quality of the display panel 110 can be improved by effectively and accurately compensating for uneven brightness in the display.

[0166] Furthermore, the brightness compensation device 300 can calculate the gamma compensation value based on the sign of the brightness compensation rate. For example, refer to... Figure 1 and Figure 7 The grayscale level calculator 340 is expected to calculate the brightness compensation rate based on the difference between a first brightness value L1 measured in response to a first reference grayscale level g1 and a target brightness value LT. In this case, it can be achieved by referring to... Figure 4 The brightness compensation rate is calculated using Equation 2 as described. Meanwhile, in Figure 7 In this context, we assume that the target brightness value LT in Equation 2 is the fourth target brightness value Lt4.

[0167] In this example, since the fourth luminance target value Lt4 is less than the first luminance value L1, the luminance compensation rate can be negative. Accordingly, the fourth expected corrected gray level gt4 calculated by the expected corrected gray level calculator 340 can be less than the first reference gray level g1. For example, the fourth expected corrected gray level gt4 can be included in the fourth unit interval SU4.

[0168] Based on a luminance compensation rate with a negative value, the compensation grayscale calculator 350 can calculate the gamma compensation value based on a fourth luminance characteristic value γ4 corresponding to the fourth unit interval SU4, rather than a first luminance characteristic value γ1 corresponding to the first unit interval SU1 including the first reference grayscale level g1. In this case, only one unit interval, i.e., the fourth unit interval SU4, can be included between the fourth desired correction grayscale level gt4 and the first reference grayscale level g1. Therefore, similar to the reference... Figure 4 As described, the grayscale compensation calculator 350 can calculate a fourth luminance characteristic value γ4 as a gamma compensation value, and by using as referenced Figure 4 Equation 4 describes the calculation of the compensated gray level GCV.

[0169] Accordingly, when the luminance value measured in response to the reference gray level is greater than the target luminance value LT (i.e., the luminance compensation rate has a negative value), the luminance compensation device 300 can more accurately calculate the compensated gray level GCV by changing the luminance characteristic value reflected when calculating the gamma compensation value. Therefore, the display quality of the display panel 110 can be further improved.

[0170] Figure 7An example case is shown where the luminance compensation rate has a negative value and there is a unit interval between the desired corrected gray level (i.e., the fourth desired corrected gray level gt4) and the reference gray level (i.e., the first reference gray level g1). However, this is merely an example, and this disclosure is not limited thereto. For example, in reference to... Figure 5 and Figure 6 In the case where there are two or more unit intervals between the desired correction gray level and the reference gray level, the luminance compensation device 300 can calculate the gamma compensation value by reflecting all luminance characteristic values ​​corresponding to the unit intervals between the reference gray level and the desired correction gray level.

[0171] For reference Figures 4 to 7 As described, the brightness compensation device 300 can determine the brightness characteristic value reflected when calculating the gamma compensation value based on a unit interval including the desired gray level correction. Accordingly, the brightness compensation device 300 can accurately calculate the gamma compensation value used to calculate the GCV of the compensated gray level. Therefore, the display quality of the display panel 110 can be improved by effectively and accurately compensating for uneven brightness in the display.

[0172] Figure 8A and Figure 8B It is used for calculation Figure 1 An example table showing the brightness characteristic values ​​of the brightness compensation device 300. In Figure 8A and Figure 8B In this context, the imaging gray level (or reference gray level) can indicate the gray level value corresponding to the reference image data RID supplied to the display panel 110 by the brightness compensation device 300, and the gray level to be corrected can indicate the gray level value when the brightness compensation device 300 calculates the desired corrected gray level and gamma compensation value based on the imaging gray level to calculate the gray level GCV compensation.

[0173] First, refer to Figure 1 and Figure 8A The brightness compensation device 300 can supply the display panel 110 with six reference image data RIDs corresponding to six reference gray levels (e.g., 32 gray levels, 64 gray levels, 96 gray levels, 128 gray levels, 196 gray levels, and 224 gray levels). Accordingly, the imaging unit 200 can capture the six reference images displayed on the display panel 110 and generate six captured image data CIDs.

[0174] The brightness characteristic value calculator 330 of the brightness compensation device 300 can calculate the brightness characteristic value corresponding to a unit interval based on the captured image data CID corresponding to two of the six reference gray levels.

[0175] For example, the brightness characteristic value calculator 330 of the brightness compensation device 300 can calculate the brightness characteristic value corresponding to a unit interval between gray levels 32 and 63 based on the captured image data CID corresponding to gray levels 32 and 64; calculate the brightness characteristic value corresponding to a unit interval between gray levels 64 and 95 based on the captured image data CID corresponding to gray levels 64 and 96; calculate the brightness characteristic value corresponding to a unit interval between gray levels 96 and 127 based on the captured image data CID corresponding to gray levels 96 and 128; calculate the brightness characteristic value corresponding to a unit interval between gray levels 128 and 195 based on the captured image data CID corresponding to gray levels 128 and 196; and calculate the brightness characteristic value corresponding to a unit interval between gray levels 196 and 223 based on the captured image data CID corresponding to gray levels 196 and 224.

[0176] In another example, where the desired correction gray level corresponding to the gray level to be corrected is less than or equal to 31 gray levels, the brightness compensation device 300 can calculate the gamma compensation value using a brightness characteristic value corresponding to a unit interval between gray levels 32 and 63. In yet another example, where the desired correction gray level corresponding to the gray level to be corrected is 225 gray levels or greater, the brightness compensation device 300 can calculate the gamma compensation value using a brightness characteristic value corresponding to a unit interval between gray levels 196 and 223. However, in these cases, the calculation of the gamma compensation value may not accurately reflect the brightness characteristics in the low gray level region of 31 gray levels or less and the high gray level region of 225 gray levels or greater.

[0177] In this embodiment, the brightness compensation device 300 can maintain the number of gray levels to be corrected for calculating the gamma compensation value, but increase the number of imaging gray levels (or reference gray levels). By reflecting the brightness characteristics in both low and high gray level areas, the gamma compensation value in both areas can be calculated more accurately.

[0178] Reference Figure 1 and Figure 8B To reflect the brightness characteristics of low grayscale areas, the brightness compensation device 300 can further supply brightness to areas smaller than the reference level. Figure 8AThe example described uses reference image data RID corresponding to 16 gray levels of the lowest gray level (i.e., 32 gray levels). Accordingly, imaging unit 200 can capture captured image data CID corresponding to 16 gray levels. The brightness characteristic value calculator 330 of brightness compensation device 300 can calculate a brightness characteristic value corresponding to a unit interval between 16 and 31 gray levels based on the captured image data CID corresponding to the two reference gray levels (i.e., 16 and 32 gray levels) of the low gray level region. Accordingly, when the desired correction gray level corresponding to the gray level to be corrected is 31 gray levels or less, brightness compensation device 300 can use the brightness characteristic value corresponding to a unit interval between 16 and 31 gray levels to calculate a gamma compensation value for calculating the compensation gray level GCV.

[0179] In addition, to reflect the brightness characteristics of high grayscale areas, the brightness compensation device 300 can further supply brightness to areas greater than the reference level. Figure 8A The example described uses reference image data RID corresponding to gray level 240 of the highest gray level (i.e., gray level 224). Accordingly, imaging unit 200 can capture captured image data CID corresponding to gray level 240. The brightness characteristic value calculator 330 of brightness compensation device 300 can calculate the brightness characteristic value corresponding to a unit interval between gray levels 224 and 239 based on the captured image data CID corresponding to the two reference gray levels (i.e., gray levels 224 and 240) in the high gray level region. Accordingly, when the desired correction gray level corresponding to the gray level to be corrected is gray level 225 or greater, brightness compensation device 300 can use the brightness characteristic value corresponding to a unit interval between gray levels 224 and 239 to calculate a gamma compensation value for calculating the compensation gray level GCV.

[0180] As described above, the brightness compensation device 300 can further calculate the brightness characteristic values ​​of the unit intervals corresponding to the low gray level area and the high gray level area. Accordingly, when calculating the gamma compensation value, the brightness characteristics of the low gray level area and the high gray level area can be accurately reflected, and the brightness compensation device 300 can calculate the gamma compensation value of the low gray level area and the gamma compensation value of the high gray level area more accurately.

[0181] Furthermore, since the number of gray levels to be corrected is maintained, it is not necessary to increase the memory capacity of the expected gray level GCV used to calculate the expected correction gray level calculator 340 and the compensation gray level GCV used to calculate the compensation gray level calculator 350. Therefore, the brightness compensation device 300 can calculate the gamma compensation value of the low gray level area and the gamma compensation value of the high gray level area more accurately without increasing the memory capacity.

[0182] Figure 9This is a flowchart illustrating a method for compensating brightness according to an embodiment of the present disclosure.

[0183] Reference Figure 1 and Figure 9 , Figure 1 The display system 1000 is executable. Figure 9 Methods for compensating for brightness. Figure 9 The method can be compared with the reference Figures 1 to 8B The operation of the described display system 1000 (and / or brightness compensation device 300) is substantially the same, and therefore repeated descriptions will be omitted.

[0184] first, Figure 9 The method can supply first to third reference image data (an example of reference image data RID) corresponding to the first to third reference gray levels to the display panel 110 (S810). Here, the configuration for supplying the reference image data RID (S810) can be as described in reference... Figure 1 and Figures 4 to 8B The configuration of the reference image data supplier 310 of the described brightness compensation device 300, which supplies reference image data RID to the display panel 110, is substantially the same. Meanwhile, as referred to... Figure 1 As described, Figure 9 The number of reference gray levels in the method is not limited to three. Figure 9 The method can provide reference image data corresponding to four or more reference gray levels.

[0185] After that, Figure 9 The method can capture first to third reference grayscale images displayed on the display panel 110 based on first to third reference image data to generate first to third captured image data (S820). Here, the configuration for capturing the reference grayscale images to generate captured image data (S820) can be as described in reference... Figure 1 and Figures 4 to 8B The configuration of the imaging unit 200, which captures the image displayed on the display panel 110 to measure brightness and generates the captured image data CID based on the reference image data RID, is substantially the same.

[0186] After that, Figure 9 The method can calculate a first luminance characteristic value corresponding to a first unit interval between a first reference gray level and a second reference gray level based on first captured image data to third captured image data, and calculate a second luminance characteristic value corresponding to a second unit interval between a second reference gray level and a third reference gray level (S830). Here, the configuration for calculating the first luminance characteristic value and the second luminance characteristic value (S830) can be as described in reference... Figure 1 and Figures 4 to 8B The configuration of the brightness compensation device 300 that calculates the brightness characteristic values ​​(e.g., first brightness characteristic value γ1, second brightness characteristic value γ2, etc.) is basically the same.

[0187] After that, Figure 9 The method can calculate the desired corrected gray level corresponding to the first reference gray level based on the first captured image data to the third captured image data (S840). Here, the configuration for calculating the desired corrected gray level (S840) can be as described in reference. Figure 1 and Figures 4 to 8B The configuration of the brightness compensation device 300 for calculating the desired correction gray level (e.g., the first desired correction gray level gt1, the second desired correction gray level gt2, etc.) is basically the same.

[0188] After that, Figure 9 The method can calculate the compensated gray level GCV (S850) corresponding to the first reference gray level based on the gamma compensation value and the desired correction gray level. Here, the configuration used to calculate the compensated gray level GCV (S850) can be as described in reference... Figure 1 and Figures 4 to 8B The configuration of the brightness compensation device 300 for calculating and compensating grayscale level GCV is basically the same as that described.

[0189] In an embodiment, when it is desired that the corrected gray level is included in the first unit interval... Figure 9 This method can determine the first luminance characteristic value as the gamma compensation value. In another case, where it is desired that the corrected gray level is included in the second unit interval... Figure 9 The method can determine the gamma compensation value based on the first luminance characteristic value and the second luminance characteristic value.

[0190] The brightness compensation device 300 according to embodiments of the present disclosure can determine the brightness characteristic value reflected when calculating the gamma compensation value based on a unit interval including the desired gray level to be corrected. Therefore, the display quality of the display panel 110 can be improved by accurately calculating the gamma compensation value used for optical compensation.

[0191] However, the effects of this disclosure are not limited to those described above, and various extensions may be made without departing from the spirit and scope of this disclosure.

[0192] The foregoing description is illustrated with reference to exemplary embodiments and provides a detailed description of this disclosure. As mentioned above, this disclosure can be used in various combinations, modifications, and environments, and can be changed or modified within the scope of the inventive concept of this disclosure, the scope equivalent to the foregoing description, and / or the skill or knowledge in the art. Therefore, the foregoing description is not intended to limit this disclosure to the forms disclosed herein. Moreover, it is intended that the appended claims be construed as including alternative embodiments of this disclosure.

Claims

1. A brightness compensation device, comprising: The brightness characteristic value calculator calculates a first brightness characteristic value corresponding to a first unit interval between the first reference gray level and the second reference gray level, and a second brightness characteristic value corresponding to a second reference gray level greater than the first reference gray level, and a third brightness value corresponding to a third reference gray level greater than the second reference gray level, based on two of the following: a first brightness value corresponding to a first reference gray level, a second brightness value corresponding to a second reference gray level greater than the first reference gray level, and a third brightness value corresponding to a third reference gray level greater than the second reference gray level. The expected correction gray level calculator calculates the expected correction gray level corresponding to the first reference gray level based on the first brightness value; as well as The grayscale compensation calculator calculates the gamma compensation value and, based on the gamma compensation value and the desired corrected grayscale level, calculates the first compensated grayscale level corresponding to the first reference grayscale level. Specifically, the grayscale compensation calculator calculates the gamma compensation value based on the first luminance characteristic value when the desired corrected grayscale level is included in the first unit interval, and calculates the gamma compensation value based on the first luminance characteristic value and the second luminance characteristic value when the desired corrected grayscale level is included in the second unit interval. In the second case, the compensation grayscale calculator calculates the gamma compensation value using the following first equation: Wherein, γt represents the gamma compensation value, γ1 represents the first luminance characteristic value, γ2 represents the second luminance characteristic value, g1 represents the first reference gray level, g2 represents the second reference gray level, and gt represents the desired correction gray level. The brightness characteristic value calculator calculates the first brightness characteristic value and the second brightness characteristic value using the following second equation: Wherein, γ1 represents the first brightness characteristic value, γ2 represents the second brightness characteristic value, L1 represents the first brightness value, L2 represents the second brightness value, L3 represents the third brightness value, g1 represents the first reference gray level, g2 represents the second reference gray level, and g3 represents the third reference gray level.

2. The brightness compensation device according to claim 1, wherein, The expected correction gray level calculator calculates the brightness compensation rate based on the difference between the first brightness value and the first brightness target value corresponding to the first reference gray level.

3. The brightness compensation device according to claim 2, wherein, The desired grayscale level calculator calculates the brightness compensation rate using the following third equation: Wherein, LCR represents the brightness compensation rate, LT represents the first brightness target value, and L1 represents the first brightness value.

4. The brightness compensation device according to claim 2, wherein, The expected gray level correction calculator calculates the expected gray level using the following fourth equation: Where gt represents the desired gray level to be corrected, g1 represents the first reference gray level, and LCR represents the brightness compensation rate.

5. The brightness compensation device according to claim 2, wherein, The compensated gray level calculator calculates the first compensated gray level using the following fifth equation: Wherein, gcv represents the first compensated gray level, g1 represents the first reference gray level, LCR represents the brightness compensation rate, and γt represents the gamma compensation value.

6. The brightness compensation device according to claim 1, wherein, The brightness characteristic value calculator further calculates a third brightness characteristic value corresponding to a third unit interval between the third reference gray level and the fourth reference gray level based on the third brightness value and a fourth brightness value corresponding to a fourth reference gray level that is greater than the third reference gray level. In the third case where the desired correction gray level is included in the third unit interval, the compensation gray level calculator calculates the gamma compensation value based on the first luminance characteristic value, the second luminance characteristic value, and the third luminance characteristic value.

7. The brightness compensation device according to claim 6, wherein, In the third case, the compensation grayscale calculator calculates the gamma compensation value using the following sixth equation: Wherein, γt represents the gamma compensation value, γ1 represents the first brightness characteristic value, γ2 represents the second brightness characteristic value, γ3 represents the third brightness characteristic value, g1 represents the first reference gray level, g2 represents the second reference gray level, g3 represents the third reference gray level, and gt represents the desired correction gray level.

8. The brightness compensation device according to claim 1, wherein, The compensation gray level calculator also calculates a second compensation gray level corresponding to the second reference gray level and a third compensation gray level corresponding to the third reference gray level, and calculates the compensation gray level corresponding to the entire gray level area by applying linear interpolation and / or linear extrapolation to the first compensation gray level, the second compensation gray level and the third compensation gray level.

9. A display system, comprising: The brightness compensation device provides first reference image data, second reference image data, and third reference image data corresponding to the first reference gray level, the second reference gray level, and the third reference gray level, respectively. The display panel displays a first reference grayscale image, a second reference grayscale image, and a third reference grayscale image based on the first reference image data, the second reference image data, and the third reference image data; as well as The imaging unit captures the first reference grayscale image, the second reference grayscale image, and the third reference grayscale image, generates first captured image data, second captured image data, and third captured image data, and provides the first captured image data, the second captured image data, and the third captured image data to the brightness compensation device. The brightness compensation device includes: A brightness characteristic value calculator calculates a first brightness characteristic value corresponding to a first unit interval between the first reference gray level and the second reference gray level based on the first captured image data and the second captured image data, and calculates a second brightness characteristic value corresponding to a second unit interval between the second reference gray level and the third reference gray level based on the second captured image data and the third captured image data; A gray-level correction calculator calculates the desired gray-level correction corresponding to the first reference gray-level based on the first captured image data; and A grayscale compensation calculator calculates a gamma compensation value, and based on the gamma compensation value and the desired corrected grayscale level, calculates a compensated grayscale level corresponding to the first reference grayscale level. Specifically, the grayscale compensation calculator calculates the gamma compensation value based on the first luminance characteristic value when the desired corrected grayscale level is included in the first unit interval, and calculates the gamma compensation value based on the first luminance characteristic value and the second luminance characteristic value when the desired corrected grayscale level is included in the second unit interval. In the second case, the compensation grayscale calculator calculates the gamma compensation value using the following first equation: Wherein, γt represents the gamma compensation value, γ1 represents the first luminance characteristic value, γ2 represents the second luminance characteristic value, g1 represents the first reference gray level, g2 represents the second reference gray level, and gt represents the desired correction gray level. The brightness characteristic value calculator calculates the first brightness characteristic value and the second brightness characteristic value using the following second equation: Wherein, γ1 represents the first brightness characteristic value, γ2 represents the second brightness characteristic value, L1 represents the first brightness value, L2 represents the second brightness value, L3 represents the third brightness value, g1 represents the first reference gray level, g2 represents the second reference gray level, and g3 represents the third reference gray level.

10. The display system according to claim 9, wherein, The brightness compensation device further includes a reference image data supplier, which supplies the first reference image data, the second reference image data, and the third reference image data to the display panel.

11. The display system according to claim 9, wherein, The display panel includes multiple pixels, and The grayscale compensation calculator calculates the grayscale compensation level for each of the plurality of pixels.

12. The display system according to claim 9, wherein, The display panel includes multiple unit blocks, and each of the multiple unit blocks includes multiple pixels. The compensation gray level calculator calculates the compensation gray level for each of the plurality of unit blocks.

13. A method for compensating the brightness of a display panel, comprising: The display panel is provided with first reference image data, second reference image data, and third reference image data corresponding to the first reference gray level, the second reference gray level, and the third reference gray level; First captured image data, second captured image data, and third captured image data are generated by capturing a first reference grayscale image, a second reference grayscale image, and a third reference grayscale image displayed on the display panel based on the first reference image data, the second reference image data, and the third reference image data; Based on the first captured image data, the second captured image data, and the third captured image data, calculate a first brightness characteristic value corresponding to a first unit interval between the first reference gray level and the second reference gray level, and a second brightness characteristic value corresponding to a second unit interval between the second reference gray level and the third reference gray level; The desired corrected gray level corresponding to the first reference gray level is calculated based on the first captured image data, the second captured image data, and the third captured image data. as well as The compensated gray level corresponding to the first reference gray level is calculated based on the gamma compensation value and the desired correction gray level. The calculation of the compensated gray level includes: In the first case where the desired correction gray level is included in the first unit interval, the gamma compensation value is calculated based on the first luminance characteristic value; and In the second case where the desired corrected gray level is included in the second unit interval, the gamma compensation value is calculated based on the first luminance characteristic value and the second luminance characteristic value. In the second case, the gamma compensation value is calculated using the following first equation: Wherein, γt represents the gamma compensation value, γ1 represents the first luminance characteristic value, γ2 represents the second luminance characteristic value, g1 represents the first reference gray level, g2 represents the second reference gray level, and gt represents the desired correction gray level. The first luminance characteristic value and the second luminance characteristic value are calculated using the following second equation: Wherein, γ1 represents the first brightness characteristic value, γ2 represents the second brightness characteristic value, L1 represents the first brightness value, L2 represents the second brightness value, L3 represents the third brightness value, g1 represents the first reference gray level, g2 represents the second reference gray level, and g3 represents the third reference gray level.

14. The method according to claim 13, wherein, In the second case, the gamma compensation value is calculated by the following seventh equation: Wherein, γt represents the gamma compensation value, γ1 represents the first brightness characteristic value, γ2 represents the second brightness characteristic value, g1 represents the first reference gray level, g2 represents the second reference gray level, and gt represents the desired correction gray level.

15. The method according to claim 13, wherein, The first captured image data includes a first brightness value displayed on the display panel corresponding to the first reference gray level.

16. The method according to claim 15, wherein, Calculating the desired corrected gray level includes: The brightness compensation rate is calculated based on the difference between the first brightness value and the first brightness target value corresponding to the first reference gray level; and The desired corrected gray level is calculated based on the brightness compensation rate.

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