Display device optical compensation method

Abstract

The present invention relates to a display device optical compensation method capable of improving productivity and power consumption of a display device by compensating color coordinates using digital gamma. The display device optical compensation method may comprise the steps of: setting a plurality of register values as gamma register values resulting from optical compensation of a sample display panel; displaying an image on a target panel with the set plurality of register values, and capturing an image of the target panel so as to measure a color coordinate value and a luminance value for each register value; and inputting, into a DLL, the measured color coordinate value and luminance value for each register value, a target color coordinate value and luminance value so as to predict, by means of a lookup table, an amount of change in each of R, G, and B registers that change when the measured color coordinate value (x, y) is adjusted to the target color coordinates, and calculating a luminance value predicted to result from the change.

Description

Optical compensation method for a display device

[0001] The present invention relates to an optical compensation method for a display device, and more specifically, to an optical compensation method for a display device that utilizes digital gamma to compensate for color coordinates as well, thereby improving the productivity and power consumption of a liquid crystal display device.

[0002] Video display devices, which display various information on a screen, are a core technology of the information and communication era and are evolving in a direction that is thinner, lighter, more portable, and higher in performance. Accordingly, display devices that can be manufactured in a lightweight and thin form are gaining attention.

[0003] Specific examples of such display devices include Liquid Crystal Display apparatus (LCD), Quantum Dot Display apparatus (QD), Field Emission Display apparatus (FED), and Organic Light Emitting Diode (OLED).

[0004] Among these image display devices, the optical characteristics of liquid crystal displays can vary from display panel to display panel due to various causes during the manufacturing process. In other words, even if the same voltage or current is applied to display panels of the same model, the color coordinates and luminance of the image implemented may differ depending on the display panel. Optical compensation techniques are known to correct for such deviations in optical characteristics between display panels.

[0005] Up until now, optical compensation technology measures color coordinates and luminance corresponding to specific preset grayscale values, and then repeats the measurement while changing the register value until the measurement result falls within the desired target range.

[0006] However, when designed in this way, there were technical problems such as an excessive number of measurements required to satisfy the target range, which caused a delay in the time required for compensation.

[0007] The problem to be solved by the present invention is to provide an optical compensation method for a display device that can drastically reduce the optical compensation time for each display panel in the product manufacturing process.

[0008] Another problem to be solved by the present invention is to provide an optical compensation method for a display device that can satisfy not only the gamma 2.2 curve but also the white balance by utilizing a digital gamma block.

[0009] The problems of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] An optical compensation method for a display device according to an embodiment of the present invention may include the steps of: setting a plurality of register values ​​as gamma register values ​​of the result of optical compensation in a sample display panel; displaying an image on a target panel with the set plurality of register values ​​and photographing the target panel to measure color coordinate values ​​and luminance values ​​for each register value; inputting the color coordinate values ​​and luminance values ​​of each measured register value and the target color coordinate values ​​and luminance values ​​into a DLL, and using a lookup table to predict the amount of change of each R, G, and B register when the measured color coordinate values ​​(x, y) are adjusted to the target color coordinates, and calculating the luminance value predicted to change at that time.

[0011] An optical compensation method for a display device according to one embodiment of the present invention may further include the step of calculating a value corresponding to a gamma 2.2 curve relative to maximum luminance, and the step of calculating a register value for a target luminance value using the difference between the luminance value corresponding to the gamma 2.2 curve in each register and the luminance value actually measured.

[0012] Specific details of other embodiments are included in the detailed description and drawings.

[0013] According to one embodiment of the present invention, since the desired correction value is obtained immediately according to a predetermined formula, the execution complexity has a constant complexity of O(1), and the execution time can be constant regardless of the degree of difference in the characteristics of each display panel for optical compensation.

[0014] This allows for reducing the time required to produce a single product by decreasing the time for optical compensation for each display panel, and furthermore, improves productivity.

[0015] The optical compensation method of a display device according to one embodiment of the present invention does not use additional IP, so the power consumption of additional IP can be reduced.

[0016] An optical compensation method for a display device according to one embodiment of the present invention can lead to an improvement in productivity compared to a method of selectively using a BLU.

[0017] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification.

[0018] FIG. 1 is a block diagram showing a liquid crystal display device according to an embodiment of the present invention.

[0019] FIG. 2 is a block diagram of a system for optical compensation of a display device according to one embodiment of the present invention.

[0020] FIG. 3 is a block diagram of a controller for optical compensation of a display device according to one embodiment of the present invention.

[0021] FIG. 4 is a flowchart of the operation of a controller (300) for optical compensation of a display device according to one embodiment of the present invention.

[0022] FIG. 5 is a table showing color coordinate values ​​(x, y) and luminance values ​​(Lv) measured by a luminance meter or the like for each X-point of a set register value according to one embodiment of the present invention.

[0023] FIG. 6a is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the R (red) register at 255 gray according to one embodiment of the present invention.

[0024] FIG. 6b is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the G (green) register at 255 gray according to one embodiment of the present invention.

[0025] FIG. 6c is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the B (blue) register at 255 gray according to one embodiment of the present invention.

[0026] FIG. 7 is a lookup table showing the color coordinates and luminance changes of each gray R, G, and B register according to one embodiment of the present invention.

[0027] FIG. 8 is a table showing tuned Y-point register values ​​calculated by a DLL according to one embodiment of the present invention.

[0028] FIG. 9 is a flowchart of the operation flowchart for adjusting the value of a register to achieve a luminance corresponding to a desired color coordinate and a gamma 2.2 curve according to one embodiment of the present invention.

[0029] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Throughout the specification, the same reference numerals denote substantially the same components.

[0030] In the following description, if it is determined that a detailed description of the technology or configuration related to the present invention could unnecessarily obscure the essence of the invention, such detailed description is omitted. Additionally, the names of components used in the following description have been selected for the ease of drafting the specification and may differ from the names of the actual product parts.

[0031] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for describing various embodiments of the present invention are exemplary, and therefore the present invention is not limited to the matters shown in the drawings. Throughout this specification, the same reference numerals refer to the same components.

[0032] Furthermore, in describing the present invention, if it is determined that a detailed description of related known technology may unnecessarily obscure the essence of the present invention, such detailed description is omitted.

[0033] Where terms such as 'includes,' 'have,' and 'consists of' are used in this specification, other parts may be added unless 'only' is used. Where a component is expressed in the singular, it includes cases where it is in the plural unless specifically stated otherwise.

[0034] In interpreting the components included in various embodiments of the present invention, they are interpreted to include an error range even without separate explicit description.

[0035] In describing various embodiments of the present invention, when describing positional relationships, for example, when the positional relationship between two parts is described using expressions such as 'on', 'on the upper part', 'on the lower part', 'next to', etc., unless 'immediately' or 'directly' is used, one or more other parts may be located between the two parts.

[0036] In describing various embodiments of the present invention, when describing temporal relationships, for example, when describing temporal sequence relationships using 'after', 'following', 'next', 'before', etc., cases that are not continuous may be included unless 'immediately' or 'directly' is used.

[0037] In describing various embodiments of the present invention, terms such as 'first~', 'second~', etc. may be used to describe various components, but these terms are used merely to distinguish between identical or similar components. Accordingly, unless otherwise stated, a component modified by 'first~' in this specification may be identical to a component modified by 'second~' within the technical scope of the present invention.

[0038] Each feature within various embodiments of the present invention may be combined or combined with one another, either partially or wholly, and may technically enable various interlocking and operation. Each of the various embodiments may be implemented independently of one another or may be implemented together in an associated relationship.

[0039] Hereinafter, a color position compensation method for a display device according to an embodiment of the present invention will be described with reference to the drawings.

[0040] FIG. 1 is a block diagram showing a liquid crystal display device according to an embodiment of the present invention.

[0041] As illustrated in FIG. 1, the liquid crystal display device may include a liquid crystal display panel (10), a timing control unit (20), a gate driving unit (30), and a data driving unit (40).

[0042] A liquid crystal display panel (10) is connected to a plurality of gate lines (GL) and a plurality of data lines (DL) and can display an image based on output image data (RGBD'). The plurality of gate lines (GL) extend in a first direction (D1), and the plurality of data lines (DL) can extend in a second direction (D2) that intersects the first direction (D1).

[0043] The liquid crystal display panel (10) may include a plurality of pixels (not shown) arranged in a matrix form. Each of the plurality of pixels may be electrically connected to one of a plurality of gate lines (GL) and one of a plurality of data lines (DL).

[0044] Each of the plurality of pixels may include a switching element, a liquid crystal capacitor electrically connected to the switching element, and a storage capacitor. The switching element may be a thin-film transistor. The liquid crystal capacitor may include a first electrode connected to a pixel electrode to which a data voltage is applied, and a second electrode connected to a common electrode to which a common voltage is applied. The storage capacitor may include a first electrode connected to the pixel electrode to which the data voltage is applied, and a second electrode connected to the storage electrode to which a storage voltage is applied. The storage voltage may have the same level as the common voltage.

[0045] In one embodiment, each of the plurality of pixels may have a rectangular shape. One side of each of the plurality of pixels may be parallel to the gate lines (GL), and the other side of each of the plurality of pixels may be parallel to the data lines (DL).

[0046] The timing control unit (20) controls the operation of the liquid crystal display panel (10) and can control the operation of the gate driver (30) and the data driver (40). The timing control unit (20) receives input image data (RGBD) and an input control signal (CONT) from an external device (e.g., a host). The input image data (RGBD) may include input pixel data for the plurality of pixels, and each of the pixel data may include red grayscale data (R), green grayscale data (G), and blue grayscale data (B) for the corresponding pixel. The input control signal (CONT) may include a master clock signal, a data enable signal, a vertical synchronization signal, a horizontal synchronization signal, etc.

[0047] The timing control unit (20) can generate output image data (RGBD'), a first control signal (CONT1), and a second control signal (CONT2) based on input image data (RGBD) and an input control signal (CONT).

[0048] Specifically, the timing control unit (20) may generate output image data (RGBD') based on input image data (RGBD) and provide it to the data driving unit (40). Similar to the input image data (RGBD), the output image data (RGBD') may include output pixel data for the plurality of pixels. According to an embodiment, the output image data (RGBD') may be image data substantially identical to the input image data (RGBD), or it may be corrected image data generated by correcting the input image data (RGBD). The timing control unit (20) may generate a first control signal (CONT1) to control the operation of the gate driving unit (30) based on the input control signal (CONT) and provide it to the gate driving unit (30). The first control signal (CONT1) may include a vertical start signal and a gate clock signal, etc. The timing control unit (20) can generate a second control signal (CONT2) to control the operation of the data driving unit (40) based on the input control signal (CONT) and provide it to the data driving unit (40). The second control signal (CONT2) may include a horizontal start signal, a data clock signal, a data load signal, a polarity control signal, etc.

[0049] Additionally, the timing control unit (20) can determine the operating frequency of the liquid crystal display panel (10). For example, the timing control unit (20) can determine the operating frequency of the liquid crystal display panel (10) as a first frequency based on input image data (RGBD), perform gamma remapping based on the first grayscale histogram of the input image data (RGBD), and selectively convert the input image data (RGBD) based on the gamma remapping result to generate output image data (RGBD'), and selectively change the operating frequency of the liquid crystal display panel (10) from the first frequency to a second frequency lower than the first frequency.

[0050] The gate driver (30) receives a first control signal (CONT1) from the timing control unit (20). The gate driver (30) can generate gate signals for driving a plurality of gate lines (GL) based on the first control signal (CONT1). The gate driver (30) can sequentially apply the gate signals to the plurality of gate lines (GL).

[0051] The data driver (40) can receive a second control signal (CONT2) and output image data (RGBD') from the timing control unit (20). The data driver (40) can generate analog data voltages based on the second control signal (CONT2) and the digital output image data (RGBD'). The data driver (40) can sequentially apply the data voltages to a plurality of data lines (DL).

[0052] In one embodiment, the data driver (40) may include a shift register (not shown), a latch (not shown), a signal processing unit (not shown), and a buffer unit (not shown). The shift register may output a latch pulse to the latch. The latch may temporarily store output image data (RGBD') and then output it to the signal processing unit. The signal processing unit may generate analog data voltages based on the digital output image data (RGBD') and output them to the buffer unit. The buffer unit may compensate the data voltages so that their levels have a constant level and output the data voltages to the data lines (DL).

[0053] According to an embodiment, the gate driver (30) and / or data driver (40) may be mounted on the liquid crystal display panel (10) or connected to the liquid crystal display panel (10) in the form of a tape carrier package (TCP). According to an embodiment, the gate driver (30) and / or data driver (40) may be integrated into the liquid crystal display panel (10).

[0054] The optical characteristics of such liquid crystal display devices can vary from display panel to display panel due to various causes during the manufacturing process. In other words, even if the same voltage or current is applied to display panels of the same model, the color coordinates and brightness of the image displayed may differ depending on the liquid crystal display panel. These deviations in optical characteristics between liquid crystal display panels must be compensated for.

[0055] FIG. 2 is a block diagram of a system for optical compensation of a display device according to one embodiment of the present invention.

[0056] As illustrated in FIG. 2, a system (200) for optical compensation of a display device according to one embodiment of the present invention may include a PC (201), a control board (202), a luminance meter (203), and a target panel (204), etc. Of course, those skilled in the art may add, change, or delete some components as needed.

[0057] In FIG. 2, the PC (201) and the control board (202) are shown as separate devices, but are not limited thereto. The PC (201) and the control board (202) can be implemented as a single device, the controller (300).

[0058] A command to measure luminance values ​​and color coordinate values, etc., can be transmitted from the PC (201) to the luminance meter (203) at a desired time. Through this, the PC (201) stores and records the luminance values ​​and color coordinate values, etc. received from the luminance meter (203). Additionally, the PC (201) can transmit necessary mipi (mobile industry processor interface) commands to the control board (202) at a desired time. Of course, while mini commands are exemplified in FIG. 2, the present invention is not limited thereto. The control board (202) may transmit mipi commands to the target panel (204) according to the commands received from the PC (201). The mipi commands used at this time may include commands to output an image to the target panel (204) according to the gray value and commands to write register values ​​for optical compensation. Furthermore, mipi commands may also include commands to transmit initial setting values ​​for driving the target panel (204).

[0059] When the luminance meter (203) receives a measurement command from the PC (201), it can measure luminance values ​​and color coordinate values, etc., at the center of the target panel (204) and transmit them to the PC (201).

[0060] I will explain assuming that the PC (201) and the control board (202) are implemented as a single device, the controller (300).

[0061] The controller (300) can transmit a first command instructing the display panel corresponding to the target panel (204) to output an image according to a specific gray value. Additionally, the controller (300) transmits a second command instructing the luminance meter (203) to photograph the display panel corresponding to the target panel (204). Accordingly, the luminance meter (203) can transmit the measured luminance value to the controller (300).

[0062] Then, in the controller (300), a correction value for optical compensation is calculated, and optical compensation is performed using the calculated correction value.

[0063] Meanwhile, a detailed embodiment of the controller (300) illustrated in FIG. 2 will be described below with reference to FIG. 3.

[0064] FIG. 3 is a block diagram of a controller (300) for optical compensation of a display device according to one embodiment of the present invention.

[0065] A controller (300) for optical compensation of a display device according to one embodiment of the present invention may include a transmission module (310), a reception module (320), and a control module (330), etc. Of course, those skilled in the art may delete, add, or change some modules as needed. In particular, the transmission module (310) and the reception module (320) may be implemented as a single transceiver.

[0066] The transmission module (310) may be designed to transmit a first command instructing the display panel corresponding to the target panel (204) to output an image according to a specific gray value, and to transmit a second command instructing the luminance meter (203) to photograph the display panel corresponding to the target panel (204). The receiving module (320) receives the luminance value measured by the luminance meter (203).

[0067] The control module (330) calculates a correction value for optical compensation and performs optical compensation using the calculated correction value. For example, for each gray, the register value for the target luminance value can be calculated at once using the difference between the target luminance value corresponding to the gamma 2.2 curve and the actual measured luminance value.

[0068] The operation of a controller (300) for optical compensation of a display device according to one embodiment of the present invention is described as follows.

[0069] FIG. 4 is a flowchart of the operation of a controller (300) for optical compensation of a display device according to one embodiment of the present invention.

[0070] The controller (300) can set the register value to the gamma register value of the optically compensated result from a normal display panel (golden sample) in advance (S1). Since the display panel has similar characteristics due to its production characteristics, it can be tuned more accurately by fine-tuning based on the tuning value of the normal display panel (golden sample).

[0071] For example, the above register value may be composed of a plurality of X-point values ​​and Y-point values. The above register value may be stored in the register of the data driving unit (400) of the target panel (204). Here, the X-point corresponds to a Gray value, and the Y-point value may correspond to the R, G, and B register values.

[0072] The above register values ​​may include multiple values. In other words, there may be multiple X-point values ​​and multiple Y-point values.

[0073] The X-point value may include multiple grays among 0 gray to 255 grays. The Y-point value may include the register values ​​of R (red), G (green), and B (blue) of each X-point value corresponding to each of the multiple grays.

[0074] For example, the X-point value may be set to 255 Gray, the R, G, and B register values ​​may be set to the Y-point of 255 Gray, the X-point value may be set to 251 Gray, the R, G, and B register values ​​may be set to the Y-point of 251 Gray, the X-point value may be set to 247 Gray, and the R, G, and B register values ​​may be set to the Y-point of 247 Gray. Here, the R, G, and B register values ​​may include positive (+) register values ​​(Rp, Gp, BP) and negative (-) register values ​​(Rn, Gn, Bn).

[0075] In this way, multiple X-point values ​​and Y-point values ​​can be stored in the registers of the data driving unit (400) of the target panel (204).

[0076] And, the target panel (204) can be driven according to the set register values ​​to display an image.

[0077] By using a luminance meter (203) or the like, a target panel (204) on which an image is displayed can be photographed to measure color coordinate values ​​(x, y) and luminance values ​​(Lv) for each set register value (S2). The controller (300) stores the measured color coordinate values ​​(x, y) and luminance values ​​(Lv).

[0078] The register values ​​stored in the register of the data driving unit (400) of the target panel (204), and the color coordinate values ​​(x, y) and luminance values ​​(Lv) measured by driving the target panel (204) with the register values ​​to display an image are described as follows.

[0079] FIG. 5 is a table showing color coordinate values ​​(x, y) and luminance values ​​(Lv) measured by a luminance meter or the like for each X-point (gray) of a set register value according to an embodiment of the present invention. FIG. 5 is an example showing, for convenience of explanation, that 30 X-points are set as register values ​​stored in the register of the data driving unit (400) of the target panel (204), and that R, G, and B register values ​​are set as Y-points for each X-point. The measured color coordinate values ​​(x, y) and luminance values ​​(Lv) are shown as examples and may not be accurate data.

[0080] As shown in FIG. 5, the grays for the 30 X-points can be set from 0 gray to 255 grays, specifically 255, 251, 247, 243, 239, 231, 223, 207, 191, 175, 159, 127, 111, 103, 95, 79, 63, 55, 47, 39, 31, 23, 15, 13, 11, 9, 7, 5, 1, and 0 grays, and for each gray, the R, G, and B register values ​​can be set as Y-points.

[0081] In this way, by driving the target panel (204) with the set register values ​​to display an image, and using a luminance meter (203) or the like to photograph the target panel (204) on which the image is displayed, and measuring the color coordinate values ​​(x, y) and luminance values ​​(Lv) for each set register value, it may be as shown in FIG. 5.

[0082] The controller (300) can call a DLL (Dynamic Link Library) for calculating correction values ​​(S3). For example, to selectively change the correction value calculation algorithm according to the model, the correction value calculation part is implemented in the form of a DLL, and the correction value is calculated through the said DLL. The correction value can be output as a tuned Y-point register value. Of course, the DLL here is merely an example and can be applied to any other type of computer program.

[0083] And, the controller (300) can store the calculated correction value according to the result of the DLL call (S4).

[0084] The above steps (S3-S4) are explained in detail as follows.

[0085] FIG. 6a is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the R (red) register at 255 gray according to one embodiment of the present invention.

[0086] FIG. 6b is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the G (green) register at 255 gray according to one embodiment of the present invention.

[0087] FIG. 6c is a graph of color coordinates (x, y) and luminance (Lv) values ​​when changing the B (blue) register at 255 gray according to one embodiment of the present invention.

[0088] FIG. 7 is a lookup table showing the color coordinates and luminance changes of each gray R, G, and B register according to an embodiment of the invention.

[0089] First, for the correction value calculation algorithm in the correction value calculation DLL, it is necessary to check the relationship between the luminance (Lv) and color coordinates (x, y) relative to the R, G, and B register values.

[0090] To verify the relationship between the register value, luminance (Lv), and color coordinate (x, y) values, the digital gamma block measures the luminance and color coordinate values ​​for each gamma register value of the sample, which may appear as shown in Figures 6a to 6c. In the case of color coordinate values, the ratio of R, G, and B register values ​​has a greater influence, so they are also affected by the reference register value of each gray. Therefore, measurement is required for each gray. The data measured for each gray is used to obtain approximate values ​​within a certain range centered on the reference register. Figures 6a to 6c are examples of data measured at 255 gray.

[0091] Specifically, as a result of measurements from multiple panels, when the R (red) register is changed at 255 gray, color coordinates (x, y) and luminance (Lv) values ​​as illustrated in FIG. 6a may be obtained. When the G (green) register is changed at 255 gray, color coordinates (x, y) and luminance (Lv) values ​​as illustrated in FIG. 6b may be obtained. When the B (blue) register is changed at 255 gray, color coordinates (x, y) and luminance (Lv) as illustrated in FIG. 6c may be obtained.

[0092] In this way, for each set register value, color coordinates (x, y) and luminance (Lv) values ​​can be obtained when changing the R, G, and B registers. For example, not only 255 gray, but also for each of the 251, 247, 243, 239, 231, 223, 207, 191, 175, 159, 127, 111, 103, 95, 79, 63, 55, 47, 39, 31, 23, 15, 13, 11, 9, 7, 5, 1, and 0 grays set in FIG. 5, color coordinates (x, y) and luminance (Lv) values ​​can be obtained when changing the R, G, and B registers.

[0093] As shown in Fig. 6a, at 255 gray, when the R (red) register is changed, the x value of the color coordinate (x, y) has a constant slope (amount of change), and the y value of the color coordinate (x, y) and the luminance (Lv) have almost no slope (amount of change) and are unstable.

[0094] As shown in Fig. 6b, at 255 gray, when the G (green) register is changed, the y value of the color coordinate (x, y) has a constant slope (amount of change), and the x value of the color coordinate (x, y) and the luminance (Lv) have almost no slope (amount of change) or are unstable.

[0095] As shown in FIG. 6c, at 255 gray, when changing the B (blue) register, the x and y values ​​of the color coordinates (x, y) have a constant slope (amount of change), and the luminance (Lv) of the B (blue) register has almost no slope (amount of change), but the color coordinates (x, y) and luminance (Lv) have an unstable change.

[0096] By calculating and organizing approximate values ​​for each register value, the values ​​of the change in color coordinates and luminance when the R, G, and B registers are changed for each gray level can be obtained as shown in Fig. 7. Through this, the change in the color coordinates and luminance values ​​of the R, G, and B registers can be predicted for each gray level.

[0097] A lookup table like the one in Fig. 7 is stored in a DLL, and the value of the register is adjusted using the lookup table like the one in Fig. 7 so that the luminance corresponds to the desired color coordinates and gamma 2.2 curve.

[0098] FIG. 8 is a table showing tuned Y-point register values ​​calculated by a DLL according to one embodiment of the present invention.

[0099] FIG. 9 is a flowchart of the operation flowchart for adjusting the value of a register to achieve a luminance corresponding to a desired color coordinate and a gamma 2.2 curve according to one embodiment of the present invention.

[0100] First, the color coordinate values ​​(x, y) and luminance values ​​(Lv) measured for each X-point (gray) described in Fig. 5, and the target color coordinate values ​​(x, y) and luminance values ​​(Lv) for each X-point (gray) are input into the DLL. Then, using a lookup table such as Fig. 7, the amount of change in each R, G, and B register that changes when the measured color coordinate values ​​(x, y) are adjusted to the target color coordinates is predicted, and the luminance value that is predicted to change at this time is also calculated (S21).

[0101] For example, as shown in FIG. 5, the measured 255 gray color coordinates (x, y) are (0.281365932, 0.309528014). And, assume the input target color coordinates (x, y) are (0.3, 0,3).

[0102] In order for the x value of the measured color coordinate (x, y) to reach the x value of the target color coordinate (x, y), the x value of the color coordinate (x, y) must increase by 0.018634068.

[0103] In addition, for the y-value of the measured color coordinate (x, y) to reach the y-value of the target color coordinate (x, y), the y-value of the color coordinate (x, y) must decrease by 0.009528014.

[0104] However, as illustrated in FIGS. 6a to 6c, the x value of the color coordinate (x, y) has a constant slope when the R (red) register is changed, and the y value of the color coordinate (x, y) has a constant slope when the G (green) register is changed. Therefore, to change the x value of the color coordinate (x, y), the R (red) register value can be used, and to change the y value of the color coordinate (x, y), the G (green) register value can be used.

[0105] In the lookup table shown in Fig. 7, at 255 gray, the change in the x value of the color coordinate (x, y) of the R register is 0.0000100, and the change in the y value of the color coordinate (x, y) of the G register is 0.0000300.

[0106] Accordingly, the DLL can calculate the change in each R, G, and B register when the measured color coordinate value (x, y) is adjusted to the target color coordinate using the change amount of the lookup table as shown in FIG. 7, and output the tuned Y-point register value as shown in FIG. 8. In FIG. 8, the tuned Y-point register values ​​may include positive (+) register values ​​(Rp, Gp, BP) and negative (-) register values ​​(Rn, Gn, Bn).

[0107] And, a value corresponding to the gamma 2.2 curve relative to the maximum luminance can be calculated (S22). For example, using [Equation 1] below, a luminance value corresponding to the gamma 2.2 curve relative to the maximum luminance for each gray can be obtained.

[0108]

[0109] Here, "targetLv(gray)" refers to the target luminance value corresponding to a specific gray value. "MaxLv" refers to the maximum luminance value, and "MinLv" refers to the minimum luminance value. "gray" refers to a given specific gray value.

[0110] Then, a correction value can be calculated (S23). For example, a register value for the target luminance value can be obtained by using the difference between the luminance value corresponding to the gamma 2.2 curve in each gray and the actually measured luminance value. However, as explained above, the target luminance value is modified by considering the predicted change in luminance when adjusted by color coordinates. After obtaining the corrected register value for luminance, the change in the R, G, and B registers that changes when the color coordinates are adjusted is applied.

[0111] The reason for using this method is that both the method for calculating the corrected register value for luminance and the method for calculating the corrected register value for color coordinates are approximate values ​​of the change amount based on the current reference gamma register value; therefore, the highest accuracy is achieved when calculating each based on the reference gamma register value. To maximize accuracy, each is calculated separately and then combined. However, when adjusting color coordinates, if the change in luminance is maintained at zero, the range of color coordinates that can be adjusted is very narrowly limited; therefore, the change in luminance is predicted and compensated for when calculating the corrected register value for luminance.

[0112] Finally, a correction value can be returned (S24). For example, the calculated correction values ​​are returned.

[0113] As explained above, the optical compensation method of a display device according to one embodiment of the present invention can obtain a desired correction value directly according to a predetermined formula, so the execution complexity is constant O(1), and the execution time can be constant regardless of the degree of difference in the characteristics of each display device for optical compensation.

[0114] This allows for a reduction in the time required to produce a single product by decreasing the time required for optical compensation for each display device. This can lead to improved productivity.

[0115] In addition, conventionally, additional IPs or backlight units (BLUs) have been used to satisfy white balance in liquid crystal display panels. However, the optical compensation method of a display device according to one embodiment of the present invention does not use additional IPs, so the power consumption of additional IPs can be reduced.

[0116] In addition, the method of selectively using BLU can lead to improved productivity.

[0117] It will be obvious to those skilled in the art that the invention described above is not limited to the embodiments and attached drawings described above, and that various substitutions, modifications, and changes are possible within the scope of the technical concept of the invention.

[0118] The modes for carrying out the invention have been sufficiently described in the aforementioned "best mode for carrying out the invention."

[0119] The present invention can be used in an optical compensation method in liquid crystal display devices, quantum dot display devices, field emission display devices, and organic light-emitting display devices.

Claims

1. A step of setting multiple register values ​​as the gamma register values ​​of the optically compensated result on a sample display panel; A step of displaying an image on a target panel with the set plurality of register values, photographing the target panel, and measuring color coordinate values ​​and luminance values ​​for each register value; and Optical compensation method for a display device comprising the step of inputting the color coordinate value and the luminance value of each measured register value and the target color coordinate value and luminance value into a DLL, and using a lookup table to predict the amount of change of each R, G, B register when the measured color coordinate value (x, y) is adjusted to the target color coordinate, and calculating the luminance value predicted to change at that time.

2. In Paragraph 1, A step of calculating a value corresponding to the maximum luminance contrast gamma 2.2 curve, and An optical compensation method for a display device, further comprising the step of calculating a register value for a target luminance value using the difference between the luminance value corresponding to the gamma 2.2 curve in each register and the actually measured luminance value.

3. In Paragraph 2, The step of calculating the luminance value corresponding to the gamma 2.2 curve relative to the maximum luminance above is an optical compensation method for a display device obtained by the following mathematical formula. Here, "targetLv(gray)" is the target luminance value corresponding to a specific gray value, "MaxLv" is the maximum luminance value, "MinLv" is the minimum luminance value, and "gray" is the given specific gray value.

4. In Paragraph 1, The above multiple register values ​​are, It consists of multiple X-point values ​​and Y-point values, and Optical compensation method for a display device, wherein each X-point corresponds to a gray value and each Y-point value corresponds to an R, G, B register value.

5. In Paragraph 4, Optical compensation method for a display device, wherein the R, G, and B register values ​​include positive (+) register values ​​and negative (-) register values.

6. In Paragraph 1, The above lookup table is, Optical compensation method of a display device, wherein for each set register value, the x and y values ​​of the color coordinates (x, y) of the R, G, and B registers are obtained relative to the Y-point register value tuned in the DLL, and for each register value, an approximation is calculated to provide the color coordinates of the R, G, and B registers and the change amount values ​​of the luminance for each register.

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