The disclosure relates to an electronic device. Particularly, the disclosure relates to a display device and a grayscale compensation method thereof.
A source driver may drive a plurality of data lines of a display panel. Because of the impedance of the data line, there may be different voltage drops (also referred to as IR drops) at different positions of the data line. For example, among a plurality of sub-pixels connected to the same data line, there may be a more serious voltage drop in a sub-pixel farther away from the source driver (the signal source), and there may be a slighter voltage drop in a sub-pixel closer to the source driver.
In addition, a plurality of data lines of a large-sized display panel are typically connected to a plurality of source drivers. A power circuit may supply power to these source drivers through a source driver power line. Therefore, because of the impedance of the source driver power line, there may also be different voltage drops at different positions of the source driver power line. For example, among a plurality of source drivers connected to the same source driver power line, there may be a more serious voltage drop in a source driver farther away from the power circuit (the power source), and there may be a slighter voltage drop in a source driver closer to the power circuit.
The disclosure provides a display device and a grayscale compensation method thereof to compensate a voltage drop of a transmission line.
In an embodiment of the disclosure, the display device includes a data conversion circuit, a voltage drop estimation circuit, and a compensation circuit. The data conversion circuit is configured to convert a plurality of original grayscale data of a target pixel block into current data. The voltage drop estimation circuit is coupled to the data conversion circuit to receive the current data of the target pixel block. The voltage drop estimation circuit is configured to convert the current data into transmission line voltage drop information of the target pixel block. The compensation circuit is coupled to the voltage drop estimation circuit to receive the transmission line voltage drop information of the target pixel block. The compensation circuit is configured to convert the transmission line voltage drop information into at least one pixel compensation value of the target pixel block, and uses the at least one pixel compensation value to compensate the plurality of original grayscale data of the target pixel block, so as to generate a plurality of compensated grayscale data of the target pixel block.
In an embodiment of the disclosure, the grayscale compensation method includes the following. A plurality of original grayscale data of a target pixel block are converted into current data by a data conversion circuit of the display device. The current data is converted into transmission line voltage drop information of the target pixel block by a voltage drop estimation circuit of the display device. The transmission line voltage drop information is converted into at least one pixel compensation value of the target pixel block by a compensation circuit of the display device. The at least one pixel compensation value is used to compensate the plurality of original grayscale data of the target pixel block by the compensation circuit, so as to generate a plurality of compensated grayscale data of the target pixel block.
Based on the foregoing, the display device in the embodiments of the disclosure may convert the original grayscale data into the current data, and then convert the current data into the transmission line voltage drop information. The display device may convert the transmission line voltage drop information into the pixel compensation value, and use the pixel compensation value to compensate the original grayscale data. Therefore, the display device may compensate the voltage drop of the transmission line.
To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
The term “coupling (or connection)” used throughout this specification (including the claims) may refer to any direct or indirect means of connection. For example, if it is herein described that a first device is coupled (or connected) to a second device, it should be interpreted that the first device may be directly connected to the second device, or the first device may be indirectly connected to the second device through other devices or some connection means. Terms such as “first” and “second” mentioned throughout this specification (including the claims) are used to name elements, or to distinguish between different embodiments or scopes, and are not used to limit the upper or lower bound of the number of elements, nor used to limit the sequence of elements. In addition, wherever possible, elements/members/steps using the same reference numerals in the drawings and embodiments denote the same or similar parts. Cross-reference may be made to relevant descriptions of elements/members/steps using the same reference numerals or using the same terms in different embodiments.
Based on the actual applications, the number n of the source drivers 120_1 to 120_n may be any integer. The plurality of source drivers 120_1 to 120_n may drive the large-sized display panel 110. The power circuit 130 may supply power to the source drivers 120_1 to 120_n through a source driver power line (a transmission line). Because of the impedance of the source driver power line, there may also be different voltage drops at different positions of the source driver power line. For example, among the plurality of source drivers 120_1 to 120_n connected to the same source driver power line, there may be a more serious voltage drop in a source driver farther away from the power circuit 130 (the power source), and there may be a slighter voltage drop in a source driver closer to the power circuit 130.
Based on the actual design, in some embodiments, the data conversion circuit 210, the voltage drop estimation circuit 220, the compensation circuit 230, and the drive circuit 240 may be integrated in a source driver integrated circuit. In some other embodiments, the driving circuit 240 may be integrated in a source driver integrated circuit, and the data conversion circuit 210, the voltage drop estimation circuit 220, and the compensation circuit 230 may be realized as another integrated circuit. In some further other embodiments, the data conversion circuit 210, the voltage drop estimation circuit 220, and the compensation circuit 230 may be integrated in a timing controller or other integrated circuits.
According to different designs, in some embodiments, the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as a hardware circuit. In other embodiments, the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as firmware, software (i.e., programs), or a combination thereof. In some embodiments, the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as a combination of multiple ones of hardware, firmware, and software.
In terms of hardware form, the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as a logic circuit on an integrated circuit. For example, the relevant functions of the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as various logic blocks, modules, and circuits in one or more controllers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), central processing units (CPUs), and/or other processing units. The relevant functions of the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as a hardware circuit, such as various logic blocks, modules, and circuits in an integrated circuit, by utilizing hardware description languages (e.g., Verilog HDL or VHDL) or other suitable programming languages.
In terms of software form and/or firmware form, the relevant functions of the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 may be realized as programming codes. For example, the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230 are realized by utilizing general programming languages (e.g., C, C++, or assembly language) or other suitable programming languages. The programming codes may be recorded/stored in a “non-transitory machine-readable storage medium”. In some embodiments, the non-transitory machine-readable storage medium includes, for example, a semiconductor memory and/or a storage device. The semiconductor memory includes a memory card, read only memory (ROM), flash memory, a programmable logic circuit, or other semiconductor memory. The storage device includes a tape, a disk, a hard disk drive (HDD), a solid-state drive (SSD), or other storage devices. Electronic equipment (e.g., a computer, CPU, a controller, a microcontroller, or a microprocessor) may read and execute the programming codes from the non-transitory machine-readable storage medium so as to realize the relevant functions of the data conversion circuit 210, the voltage drop estimation circuit 220, and (or) the compensation circuit 230. Alternatively, the programming codes may be provided to the electronic equipment via any transmission medium (e.g., a communication network or a radio wave). The communication network is, for example, the Internet, a wired communication network, a wireless communication network, or other communication media.
In the embodiment shown in
With reference to
It is assumed that the target pixel block includes a plurality of red sub-pixels, a plurality of green sub-pixels, and a plurality of blue sub-pixels. The data conversion circuit 210 may average red sub-pixel current values to generate a red current average value. The data conversion circuit 210 may average green sub-pixel current values to generate a green current average value. The data conversion circuit 210 may average blue sub-pixel current values to generate a blue current average value. The data conversion circuit 210 may perform weighting calculation on the red current average value, the green current average value, and the blue current average value of the target pixel block to generate the current data DI corresponding to the target pixel block. For example (but not limited thereto), the data conversion circuit 210 may calculate Formula (2) below. In Formula (2), DI represents the current data corresponding to the target pixel block, Wr represents the red weight, R represents the red current average value, Wg represents the green weight, G represents the green current average value, Wb represents the blue weight, B represents the blue current average value, and M represents the maximum grayscale value (e.g., 255 or other real numbers). The values of the red weight Wr, the green weight Wg, and the blue weight Wb may be set depending on the actual design.
With reference to
The voltage drop estimation circuit 220 may count the current accumulation values of the pixel blocks 611 to 618 of the same pixel block column along the transmission direction of the transmission line to know the voltage drop characteristic value corresponding to each pixel block. The voltage drop characteristic value of the pixel block 618 is IRD68=CA68. The voltage drop characteristic value of the pixel block 617 is IRD67=IRD68+CA67. The voltage drop characteristic value of the pixel block 616 is IRD66=IRD67+CA66. The voltage drop characteristic value of the pixel block 615 is IRD65=IRD66+CA65. The voltage drop characteristic value of the pixel block 614 is IRD64=IRD65+CA64. The voltage drop characteristic value of the pixel block 613 is IRD63=IRD64+CA63. The voltage drop characteristic value of the pixel block 612 is IRD62=IRD63+CA62. The voltage drop characteristic value of the pixel block 611 is IRD61=IRD62+CA61.
The voltage drop estimation circuit 220 may use the voltage drop characteristic value of the target pixel block and the reference voltage drop characteristic value of the target pixel block to calculate the 1-D voltage drop ratio (the transmission line voltage drop information). The reference voltage drop characteristic value may be set depending on the actual design. For example, the reference voltage drop characteristic value includes a maximum voltage drop characteristic value of the target pixel block in a case where each sub-pixel of all pixel blocks corresponding to the transmission line (the data line) is a maximum grayscale. It is assumed that the maximum voltage drop characteristic values of the pixel blocks 611 to 618 shown in
In the scenario shown in
The voltage drop estimation circuit 220 may count the current accumulation values of the pixel block columns 711 to 718 along a transmission direction of the transmission line to know the voltage drop characteristic value corresponding to each pixel block column. The voltage drop characteristic value of the pixel block column 718 is IRD78=CA78. The voltage drop characteristic value of the pixel block column 717 is IRD77=IRD78+CA77. The voltage drop characteristic value of the pixel block column 716 is IRD76=IRD77+CA76. The voltage drop characteristic value of the pixel block column 715 is IRD75=IRD76+CA75. The voltage drop characteristic value of the pixel block column 714 is IRD74=IRD75+CA74. The voltage drop characteristic value of the pixel block column 713 is IRD73=IRD74+CA73. The voltage drop characteristic value of the pixel block column 712 is IRD72=IRD73+CA72. The voltage drop characteristic value of the pixel block column 711 is IRD71=IRD72+CA71.
The voltage drop estimation circuit 220 may use the voltage drop characteristic value of a target pixel block column and a reference voltage drop characteristic value of the target pixel block column to calculate the 2-D voltage drop ratio (the transmission line voltage drop information). The reference voltage drop characteristic value of the target pixel block column may be set depending on the actual design. For example, the reference voltage drop characteristic value of the target pixel block column includes a maximum voltage drop characteristic value of the target pixel block column in a case where each sub-pixel of the target pixel block column is a maximum grayscale. It is assumed that the maximum voltage drop characteristic values of the pixel block columns 711 to 718 shown in
With reference to
As an example, the at least one lookup table may include a maximum (Max) loading condition lookup table and a minimum (Min) loading condition lookup table, the first compensation value corresponding to the target pixel block includes a maximum loading condition compensation value and a minimum loading condition compensation value, and the transmission line voltage drop information of the target pixel block includes the 1-D voltage drop ratio and the 2-D voltage drop ratio corresponding to the target pixel block. The content of the maximum loading condition lookup table may be ideal compensation values (the maximum loading condition compensation values) corresponding to pixel blocks at different positions in a case where all pixels of the display panel emit light at the maximum grayscale. The content of the minimum loading condition lookup table may be ideal compensation values (the minimum loading condition compensation values) corresponding to pixel blocks at different positions in a case where all pixels of the display panel emit light at the minimum grayscale. The compensation circuit 230 may obtain the maximum loading condition compensation value corresponding to the target pixel block from the maximum loading condition lookup table based on the position of the target pixel block in the display panel. In addition, the compensation circuit 230 may obtain the minimum loading condition compensation value corresponding to the target pixel block from the minimum loading condition lookup table based on the position of the target pixel block.
The compensation circuit 230 may use the maximum loading condition compensation value, the minimum loading condition compensation value, the 1-D voltage drop ratio, and the 2-D voltage drop ratio to calculate the second compensation value of the target pixel block. For example (but not limited thereto), the compensation circuit 230 may calculate Formula (3) below. In Formula (3), Comp represents the second compensation value, Cmin represents the minimum loading condition compensation value, Cmax represents the maximum loading condition compensation value, R1D represents the 1-D voltage drop ratio, and R2D represents the 2-D voltage drop ratio.
In some embodiments, the compensation circuit 230 may use the second compensation value as the at least one pixel compensation value. In some other embodiments, the compensation circuit 230 may convert the second compensation value of the target pixel block into the at least one pixel compensation value of the target pixel block. With reference to
As an example, in some embodiments, the at least one pixel compensation value includes a plurality of sub-pixel compensation values corresponding to different sub-pixels in the target pixel block. The compensation circuit 230 may convert the second compensation value of the target pixel block into the sub-pixel compensation value corresponding to each of a plurality of edge sub-pixels of the target pixel block. For example (but not limited thereto), the compensation circuit 230 may use the second compensation value of the target pixel block and the second compensation value of an adjacent pixel block adjacent to the target pixel block to perform interpolation/extrapolation to calculate the second compensation values of the plurality of edge sub-pixels (e.g., sub-pixels at four corners) of the target pixel block. The compensation circuit 230 may use the sub-pixel compensation values of these edge sub-pixels to perform interpolation/extrapolation to calculate the sub-pixel compensation value corresponding to each of the other sub-pixels in the target pixel block. Therefore, the compensation circuit 230 may use the pixel compensation values corresponding to different sub-pixels to compensate the original grayscale data of different sub-pixels, so as to generate the compensated grayscale data D2 of these sub-pixels.
In the embodiment shown in
The block average circuit 212 is coupled to the current index mapping circuit 211 to receive the sub-pixel current values. The block average circuit 212 may perform average calculation on the sub-pixel current values of the target pixel block according to colors to generate a plurality of color current average values of the target pixel block. It is assumed that the target pixel block includes a plurality of red sub-pixels, a plurality of green sub-pixels, and a plurality of blue sub-pixels. The block average circuit 212 may average red sub-pixel current values to generate a red current average value R. The block average circuit 212 may average green sub-pixel current values to generate a green current average value G. The block average circuit 212 may average blue sub-pixel current values to generate a blue current average value B.
The color weighting circuit 213 is coupled to the block average circuit 212 to receive the color current average values. The color weighting circuit 213 may perform weighting calculation on the color current average values of the target pixel block to generate the current data DI of the target pixel block. For example (but not limited thereto), the data conversion circuit 210 may calculate Formula (2) above to generate the current data DI of the target pixel block.
In the embodiment shown in
In addition, the current accumulation circuit 221 may sum up the current data of all pixel blocks in any pixel block column to know column current data of each pixel block column. The current accumulation circuit 221 may accumulate the column current data of different pixel block columns along an inverse transmission direction of the source driver power line to know a column current accumulation value corresponding to each pixel block column. For example (but not limited thereto), with reference to the relevant description of
The voltage drop calculation circuit 222 is coupled to the current accumulation circuit 221 to receive the current accumulation value and the column current accumulation value. The voltage drop calculation circuit 222 may count the current accumulation values of different pixel blocks in the same pixel block column along the transmission direction of the data line to know a column voltage drop characteristic value (a column IR drop characteristic value) corresponding to each pixel block in the same pixel block column. For example (but not limited thereto), with reference to the relevant description of
In addition, the voltage drop calculation circuit 222 may count the column current accumulation values of different pixel block columns along the transmission direction of the source driver power line to know a row voltage drop characteristic value (a row IR drop characteristic value) corresponding to each pixel block column. For example (but not limited thereto), with reference to the relevant description of
The 1-D ratio circuit 223 is coupled to the voltage drop calculation circuit 222 to receive the column voltage drop characteristic value. The 1-D ratio circuit 223 may use the column voltage drop characteristic value of the target pixel block and a reference column voltage drop characteristic value of the target pixel block to calculate a 1-D voltage drop ratio corresponding to the target pixel block. For example, assuming that the column voltage drop characteristic value of the target pixel block is IRD68 and the reference column voltage drop characteristic value of the target pixel block is IRDM68, then the 1-D voltage drop ratio (the transmission line voltage drop information) of the target pixel block is R1D68=IRD68/IRDM68.
The 2-D ratio circuit 224 is coupled to the voltage drop calculation circuit 222 to receive the row voltage drop characteristic value. The 2-D ratio circuit 224 may use the row voltage drop characteristic value of a target pixel block column corresponding to the target pixel block and a reference row voltage drop characteristic value of the target pixel block column to calculate a 2-D voltage drop ratio corresponding to the target pixel block. For example, assuming that the row voltage drop characteristic value of the target pixel block column corresponding to the target pixel block is IRD78 and the reference row voltage drop characteristic value of the target pixel block column is IRDM78, then the 2-D voltage drop ratio (the transmission line voltage drop information) of the target pixel block is R2D78=IRD78/IRDM78.
In the embodiment shown in
For example (but not limited thereto), the at least one lookup table may include a maximum loading condition lookup table and a minimum loading condition lookup table. The lookup table circuit 231 may obtain the maximum loading condition compensation value corresponding to the target pixel block from the maximum loading condition lookup table, and obtain the minimum loading condition compensation value corresponding to the target pixel block from the minimum loading condition lookup table based on the position of the target pixel block in the display panel. Using the maximum loading condition compensation value and the minimum loading condition compensation value (the first compensation value), and using the 1-D voltage drop ratio and the 2-D voltage drop ratio (the transmission line voltage drop information) of the target pixel block, the lookup table circuit 231 may calculate the second compensation value of the target pixel block. For example, the lookup table circuit 231 may calculate Formula (3) above to generate the second compensation value of the target pixel block.
The compensation value generation circuit 232 is coupled to the lookup table circuit 231 to receive the second compensation value. The compensation value generation circuit 232 may convert the second compensation value of the target pixel block into at least one pixel compensation value of the target pixel block (e.g., the sub-pixel compensation values corresponding to a plurality of edge sub-pixels of the target pixel block). For example, the compensation value generation circuit 232 may use the second compensation value of the target pixel block and the second compensation value of an adjacent pixel block adjacent to the target pixel block to perform interpolation/extrapolation to calculate the second compensation values of the plurality of edge sub-pixels (e.g., the second compensation values of sub-pixels at four corners) of the target pixel block. Then, the compensation value generation circuit 232 may use the second compensation values (the sub-pixel compensation values) of these edge sub-pixels to perform interpolation/extrapolation to calculate the sub-pixel compensation value corresponding to each of the other sub-pixels in the target pixel block.
The grayscale compensation circuit 233 is coupled to the compensation value generation circuit 232 to receive the pixel compensation value. The grayscale compensation circuit 233 may use the pixel compensation value to compensate the original grayscale data of the target pixel block, so as to generate the compensated grayscale data D2 of the target pixel block.
In summary of the foregoing, the display device according to the embodiments above may convert the original grayscale data D1 into the current data, then convert the current data into the transmission line voltage drop information, further convert the transmission line voltage drop information into the pixel compensation value, and use the pixel compensation value to compensate the original grayscale data D1. Therefore, the display device may compensate the voltage drop of the transmission line.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.