Color difference compensation circuit and driving device for display using the same

Abstract

A color difference compensation circuit for preventing the color of a pixel from changing when color difference compensation is performed on the pixel and a driving device for a display using the color difference compensation circuit are provided. The color difference compensation circuit includes: a color difference memory configured to store color difference information, the color difference information including position information of a pixel having color difference and a compensation value of its color; a gain adjustment unit configured to provide an adjustment compensation value generated by applying an adjustment gain having the same ratio to the compensation value of the color of the pixel; and a color difference compensation unit configured to receive display data of the color of the pixel and perform color difference compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information.

Description

Technical Field

[0001] The present disclosure relates to color difference compensation, and more particularly, to a color difference compensation circuit for preventing color changes of pixels when color difference compensation is performed on the pixels, and a driving device for a display using the color difference compensation circuit. Background Art

[0002] Recently, an LCD panel or an OLED panel is widely used as a display panel.

[0003] Color aberration can occur in display panels due to reasons such as errors in the manufacturing process. Color aberration means that pixels or a certain area of ​​the displayed image have uneven brightness in the form of stains. Defects that occur due to color aberration are called color aberration defects.

[0004] In order to make the display panel have improved image quality, it is necessary to compensate for the color difference defect.

[0005] Various methods may be used to calculate a compensation value for compensating for the color difference of a pixel. In general, a compensation value having a gain of 100% is applied.

[0006] To compensate for chromatic aberration, a convergence function may be added. A convergence function is a technique for applying gain to a compensation value differently according to an input grayscale level.

[0007] In a high gray level range, if a color difference compensation value having a gain of 100% is applied for color difference compensation, the gray level may be quickly saturated. In addition, in the case of a low gray level range, it is difficult to predict the compensation value.

[0008] Therefore, the convergence function is implemented to weakly apply the compensation gain from a specific gray level to the lowest gray level in the low gray level range, or to weakly apply the compensation gain from a specific gray level to the highest gray level in the high gray level range.

[0009] However, the color difference compensation method has problems in compensating the color difference of colors.

[0010] Illustratively, a pixel may include a combination of three colors: red R, blue B, and green G. To represent the color of a pixel, the grayscale level of red R may belong to a range in which a compensation value having a gain of 100% is applied. The grayscale level of blue B or green G may belong to a high grayscale level range or a low grayscale level range in which a convergence function is applied.

[0011] In this case, in order to compensate for the color difference of the pixel, the grayscale level of red R may be compensated by a gain of 100%, but the grayscale level of blue B or green G has a compensation range where the gain is lower than 100%.

[0012] As described above, if the color difference of a pixel is compensated by a gain having the same level for each color, the ratio of red R, blue B, and green G constituting the color of the pixel changes. As a result, the color of the pixel changes.

[0013] Schematically, the skin color may become green.

[0014] Since color difference compensation is performed by applying gains having the same level to gray scales, a change in color occurs.

[0015] Therefore, when color difference compensation is performed on the color of a pixel, it is necessary to develop a color difference compensation method that can suppress color changes. Summary of the invention

[0016] Various embodiments are directed to providing a color difference compensation circuit capable of preventing color changes of pixels when color difference compensation is performed on the pixels, and a driving device for a display using the color difference compensation circuit.

[0017] In addition, various embodiments aim to provide a chromatic aberration compensation circuit and a driving device for a display using the chromatic aberration compensation circuit, which is capable of suppressing color changes of pixels caused by chromatic aberration compensation by applying adjustment gains with the same ratio to colors to compensate for the chromatic aberration of pixels.

[0018] In addition, various embodiments aim to provide a chromatic aberration compensation circuit and a driving device for a display using the chromatic aberration compensation circuit, which is capable of suppressing the color change of pixels caused by chromatic aberration compensation by performing chromatic aberration compensation on pixels in consideration of different brightness change characteristics for each color.

[0019] In an embodiment, a chromatic aberration compensation circuit may include: a memory configured to store chromatic aberration information including position information of a pixel having chromatic aberration and a compensation value of its color; a gain adjustment unit configured to provide an adjustment compensation value generated by applying an adjustment gain having the same ratio to the compensation value of the color of the pixel; and a chromatic aberration compensation unit configured to receive display data of the color of the pixel and perform chromatic aberration compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information.

[0020] In an embodiment, a driving device for a display may include: a recovery unit configured to recover display data from a data group; a memory configured to store color difference information, the color difference information including position information of a pixel having color difference and a compensation value of its color; a gain adjustment unit configured to provide an adjustment compensation value generated by applying an adjustment gain having the same ratio to the compensation value of the color of the pixel; a color difference compensation unit configured to receive display data of the color of the pixel and perform color difference compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information; a gamma circuit configured to provide a gamma voltage for each grayscale level; a digital-to-analog converter configured to select a gamma voltage corresponding to the display data output by the color difference compensation unit and output the selected gamma voltage as an analog signal; and an output circuit configured to output a source signal for driving the analog signal.

[0021] The present disclosure applies adjustment gains having the same ratio to the colors of the pixels when performing color difference compensation on the pixels.

[0022] Therefore, the present disclosure can maintain the color of the pixel on which the color difference compensation is performed because the color combination ratio for expressing the pixel does not significantly change despite the performance of the color difference compensation.

[0023] Furthermore, since color difference compensation may be performed in consideration of brightness variation characteristics that differ for each color of a pixel, the present disclosure may suppress color variation of a pixel due to color difference compensation.

[0024] Therefore, the present disclosure has the effect that, since color difference compensation can be performed without significant change in the original color of a pixel, image quality can be improved and reliability of a driving circuit and a display device can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram illustrating a color difference compensation circuit according to an embodiment of the present disclosure and a driving device for a display to which the color difference compensation circuit is applied.

[0026] Figure 2 is a schematic diagram showing color difference.

[0027] Figure 3 is a graph showing the relationship between the input grayscale level and the gain of the convergence function.

[0028] Figure 4 is a graph showing application of adjustment gains with given ratios according to an embodiment of the present disclosure.

[0029] Figure 5 is a graph showing luminance change characteristics corresponding to the grayscale level of each color of a pixel. DETAILED DESCRIPTION

[0030] An embodiment of the present disclosure is configured to apply adjustment gains having the same ratio to compensation values ​​to prevent color variation of pixels due to color difference compensation.

[0031] For the driving device for a display according to the embodiment of the present disclosure, reference may be made to Figure 1 .exist Figure 1 In the embodiment, the color difference compensation circuit can be understood as including a color difference compensation unit 40, a gain adjustment unit 30 and a color difference memory 20.

[0032] exist Figure 1 In the embodiment, the driving device 100 includes a restoration unit 10, a color difference memory 20, a gain adjustment unit 30, a color difference compensation unit 40, a digital-to-analog converter (DAC) 50, a gamma circuit 60, and an output circuit 70.

[0033] The driving device 100 may provide a source signal to a display panel (not shown) according to an input data packet, and may perform color difference compensation on color difference pixels.

[0034] In the driving apparatus 100, the restoration unit 10 receives the data packet and restores the display data from the data packet.

[0035] A pixel may have a color represented by a combination of three colors: red R, blue B, and green G. Therefore, the data packet includes display data corresponding to red R, blue B, and green G. The restoration unit 10 restores the display data of red R, blue B, and green G corresponding to one pixel in sequence.

[0036] In addition to display data, the data packet may also include a clock required for display, control data, etc. The recovery unit 10 may also recover the clock and control data and provide the clock and control data to necessary components.

[0037] In a display panel, color difference can occur in pixel or block units. Figure 2 To understand the color difference formed in the block unit. Figure 2 In , "MB" indicates a color difference block. Each pixel included in the color difference block MB can be understood as having a color difference.

[0038] like Figure 2 As shown, each pixel may have position information. The pixel P may be configured to have position information for row and column position values. Schematically, Figure 2 The position information of the upper leftmost pixel P may be defined as (188, 80).

[0039] In addition, Figure 2 In the embodiment, a compensation value for compensating a color difference of a distorted color may be set for each pixel included in the color difference block MB.

[0040] In case of a color mode (or RGB mode), compensation values ​​for color difference compensation may be defined for display data corresponding to red R, display data corresponding to blue B, and display data corresponding to green G, respectively.

[0041] As described above, the position information of the pixel having color difference and the compensation value for the color may be obtained during the test process.

[0042] A method of calculating a compensation value during a test may be variously set according to a manufacturer's intention, and a detailed description thereof is omitted.

[0043] The compensation values ​​calculated during the test as described above may be stored in the color difference memory 20 of the driving device 100 .

[0044] Therefore, the color difference memory 20 may store color difference information including position information of pixels having color difference and compensation values ​​for colors thereof.

[0045] The gain adjustment unit 30 is configured to provide an adjustment compensation value, wherein the adjustment compensation value is generated by applying an adjustment gain having the same ratio to a compensation value of a color of a pixel. Figure 3 and Figure 4 The detailed operation of the gain adjustment unit 30 is described.

[0046] Furthermore, the color difference compensation unit 40 may receive display data of the color of the pixel from the restoration unit 10, and may provide the position information of the pixel to the gain adjustment unit 30. Furthermore, the color difference compensation unit 40 receives an adjustment compensation value corresponding to the position information provided by the gain adjustment unit 30.

[0047] Furthermore, the color difference compensation unit 40 performs color difference compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information, and outputs the display data of the color of the pixel on which the color difference compensation has been performed.

[0048] The color difference compensation of the display data of the color of the pixel can be understood to be performed in sequence.

[0049] The DAC 50 may output the display data output by the color difference compensation unit 40 as an analog signal.

[0050] The DAC 50 may be understood to include a latch for latching display data, a shift register for shifting the latched display data, and a digital-to-analog conversion circuit for converting the shifted display data into an analog signal, and is briefly shown for convenience of description.

[0051] The gamma circuit 60 is configured to provide the DAC 50 with the same number of gamma voltages as the number of gray levels within the gray level range.

[0052] Therefore, the DAC 50 may select a gamma voltage corresponding to a digital value of display data, and may output the selected gamma voltage as an analog signal.

[0053] The output circuit 70 may output a source signal for driving the analog signal output by the DAC 50 , and may be configured to use an output buffer, for example.

[0054] As described above, the gain adjustment unit 30 is configured to prevent the color of the pixel from changing when the color difference compensation is performed on the pixel, and to provide an adjustment gain having the same ratio to be applied to the color of the pixel.

[0055] To this end, the gain adjustment unit 30 receives the display data and the position information of the pixel from the color difference compensation unit 40. The position information may be included in the control data corresponding to the display data, and a detailed example thereof is omitted.

[0056] The gain adjustment unit 30 receives the compensation value of the color corresponding to the position information from the color difference memory 20 , generates an adjustment compensation value by applying an adjustment gain having the same ratio to the compensation value of the color, and provides the adjustment compensation value to the color difference compensation unit 40 .

[0057] Illustratively, the gain adjustment unit 30 may select a lowest compensation ratio of compensation ratios applied to gray levels of display data as an adjustment gain for a color of a pixel, and may generate and provide an adjustment compensation value.

[0058] Reference Figure 3 and Figure 4 Describe this in detail.

[0059] Can be as Figure 3 Set the compensation ratio of the input grayscale level, that is, the compensation gain.

[0060] exist Figure 3 , the lowest gray level is indicated as "LE", the first gray level is indicated as "LS", the second gray level is indicated as "HS", and the highest gray level is indicated as "HE". In this case, the second gray level HS is higher than the first gray level, and if the gray level range is set from gray level 0 to gray level 255, illustratively, the first gray level may be set to gray level 64, and the second gray level may be set to gray level 192.

[0061] In addition, "LC" indicates a low gray level range of the lowest gray level LE or more to less than the first gray level LS. "NC" indicates an intermediate gray level range of the first gray level LS or more to the second gray level HS or less. "HC" indicates a high gray level range of greater than the second gray level HS to the highest gray level HE or less.

[0062] like Figure 3 As shown, if the input gray level corresponds to the middle gray level range NC, a compensation ratio of 100% is applied.

[0063] If the input gray level belongs to the low gray level range LC, a lower compensation ratio is applied as the gray level becomes lower.

[0064] Furthermore, if the input grayscale level belongs to the high grayscale level range HC, a lower compensation ratio is applied as the grayscale level becomes higher.

[0065] The convergence function is applied to the low gray level range LC and the high gray level range HC. In the low gray level range and the high gray level range, the compensation ratio of the compensation value is differently applied according to the gray level.

[0066] In an embodiment of the present disclosure, the gain adjustment unit 30 is configured to provide an adjustment compensation value generated by applying adjustment gains having the same ratio to compensation values ​​of colors of pixels.

[0067] That is to say, Figure 4 As shown, the adjustment gain A having the same ratio may be applied to the compensation value of the color.

[0068] exist Figure 4 In FIG. 1 , F(Xr) is the compensation value of red R, A is the adjustment gain, and Yr is the adjustment compensation value of red R. In addition, F(Xg) is the compensation value of green G, and Yg is the adjustment compensation value of green G. In addition, F(Xb) is the compensation value of blue B, and Yb is the adjustment compensation value of blue B.

[0069] like Figure 4 As shown, the embodiments of the present disclosure may provide adjustment compensation values ​​Yr, Yg, and Yb, which are generated by applying adjustment gains A having the same ratio to compensation values ​​of colors of pixels.

[0070] In this case, although color difference compensation is performed on the pixel, the ratio of red R, blue B, and green G constituting the color of the pixel may be maintained. The color of the pixel represented by the combination of red R, blue B, and green G may be maintained.

[0071] For example, the lowest compensation ratio of the compensation ratios of the grayscale levels of the display data applied to the pixels may be selected and applied as the adjustment gain having the same ratio as that applied to the colors of the pixels.

[0072] Colors can have different brightness variation characteristics. Figure 5 The luminance change characteristics corresponding to the grayscale level of the pixel color are shown.

[0073] Therefore, the gain adjustment unit 30 may have color characteristic compensation values ​​for one or two or more colors in order to compensate for brightness variation characteristics that differ for each color, and may additionally apply the characteristic compensation values ​​to the compensation values ​​of the colors.

[0074] In this case, the brightness variation characteristics that differ for each color of the pixel can be compensated when the color difference compensation is performed on the pixel, and the variation of the color of the pixel due to the color difference compensation can be effectively suppressed.

[0075] Therefore, the present disclosure has the effect that, since color difference compensation is possible without significant change in the original color of a pixel, image quality can be improved and reliability of a driving circuit and a display device can be ensured.

Claims

1. A color difference compensation circuit, comprising: A color difference memory configured to store color difference information, the color difference information including position information of pixels with color difference and compensation values ​​of colors of the pixels; a gain adjustment unit configured to provide an adjustment compensation value generated by applying an adjustment gain having a same ratio to the compensation value of the color of the pixel; as well as a color difference compensation unit configured to receive the display data of the color of the pixel and perform color difference compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information, Wherein, the gain adjustment unit: having a color characteristic compensation value for at least one color to compensate for brightness variation characteristics that are different for each color, and The adjustment compensation value generated by applying the color characteristic compensation value to the at least one color is provided.

2. The color difference compensation circuit according to claim 1, wherein: The gain adjustment unit: receiving the position information from the chromatic aberration compensation unit, receiving the compensation value of the color corresponding to the position information from the color difference memory, generating the adjusted compensation value generated by applying the adjustment gain having the same ratio to the compensation value, and The adjustment compensation value is provided to the color difference compensation unit.

3. The color difference compensation circuit according to claim 2, wherein: The gain adjustment unit: also receiving the display data of the color of the pixel from the color difference compensation unit, and The lowest compensation ratio among the compensation ratios applied to the grayscale levels of the display data is selected as the adjustment gain for the color of the pixel, and the adjustment compensation value is generated and provided.

4. The color difference compensation circuit according to claim 3, wherein: The gain adjustment unit applies the compensation ratio which becomes lower as the grayscale level becomes lower in a low grayscale level range from a lowest grayscale level or more to a preset first grayscale level or less, applies the same compensation ratio to each grayscale level in a middle grayscale level range from the first grayscale level or more to a preset second grayscale level or less, and applies the compensation ratio which becomes lower as the grayscale level becomes higher in a high grayscale level range from the second grayscale level to a maximum grayscale level or less, and The second grayscale level is higher than the first grayscale level.

5. The color difference compensation circuit according to claim 3, wherein: The gain adjustment unit applies the compensation ratio which becomes lower as the grayscale level becomes lower, within a low grayscale level range of a lowest grayscale level or more to less than a preset first grayscale level.

6. The color difference compensation circuit according to claim 3, wherein: The gain adjustment unit applies the compensation ratio which becomes lower as the gray level becomes higher, within a high gray level range from greater than a preset second gray level to a maximum gray level or less.

7. The color difference compensation circuit according to claim 1, wherein: The gain adjustment unit: having color characteristic compensation values ​​for two or more colors, and The adjustment compensation value generated by applying the color characteristic compensation value to the two or more colors is provided.

8. A driving device for a display, comprising: a recovery unit configured to recover display data from the data group; A color difference memory configured to store color difference information, the color difference information including position information of pixels with color difference and compensation values ​​of colors of the pixels; a gain adjustment unit configured to provide an adjustment compensation value generated by applying an adjustment gain having a same ratio to the compensation value of the color of the pixel; a color difference compensation unit configured to receive the display data of the color of the pixel and perform color difference compensation on the display data of the color of the pixel using the adjustment compensation value corresponding to the position information; a gamma circuit configured to provide a gamma voltage for each grayscale level; a digital-to-analog converter configured to select a gamma voltage corresponding to the display data output by the color difference compensation unit and output the selected gamma voltage as an analog signal; as well as an output circuit configured to output a source signal for driving the analog signal, Wherein, the gain adjustment unit: having a color characteristic compensation value for at least one color to compensate for brightness variation characteristics that are different for each color, and The adjustment compensation value generated by applying the color characteristic compensation value to the at least one color is provided.

9. The driving device according to claim 8, wherein: The gain adjustment unit: receiving the position information from the chromatic aberration compensation unit, receiving the compensation value of the color corresponding to the position information from the color difference memory, generating the adjusted compensation value by applying the adjustment gain having the same ratio to the compensation value, and The adjustment compensation value is provided to the color difference compensation unit.

10. The driving device according to claim 9, wherein: The gain adjustment unit: also receiving the display data of the color of the pixel from the color difference compensation unit, and The lowest compensation ratio among the compensation ratios applied to the grayscale levels of the display data is selected as the adjustment gain of the color of the pixel, and the adjustment compensation value is generated and provided.

11. The driving device according to claim 10, wherein: The gain adjustment unit applies the compensation ratio which becomes lower as the grayscale level becomes lower in a low grayscale level range from a lowest grayscale level or more to a preset first grayscale level or less, applies the same compensation ratio to each grayscale level in a middle grayscale level range from the first grayscale level or more to a preset second grayscale level or less, and applies the compensation ratio which becomes lower as the grayscale level becomes higher in a high grayscale level range from the second grayscale level to a maximum grayscale level or less, and The second grayscale level is higher than the first grayscale level.

12. The driving device according to claim 8, wherein: The gain adjustment unit: having color characteristic compensation values ​​for two or more colors, and The adjustment compensation value generated by applying the color characteristic compensation value to the two or more colors is provided.

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