TWI473068B - Overdrive device for display and related method - Google Patents

Description

Overdrive device for display and related method

The present invention relates to an overdrive device applied to a display, and more particularly to an overdrive device and related method that can avoid erroneous overdrive values caused by compression errors.

Conventional liquid crystal displays sometimes have residual images when displaying moving images. Therefore, the industry has developed an over-drive method by applying an electric field strength higher than the original steady state. The reaction speed of the liquid crystal is accelerated so that the liquid crystal can be rotated to a predetermined angle in a short time. For example, if the pixel value of one pixel of the display is to be converted from 100 to 200, the overdrive device in the display will first set the pixel value to be converted to 230 (that is, first use a larger driving voltage for fast rotation). Liquid crystal molecules), and then return to the target pixel value of 200. Such a driving method of applying an excessive electric field to accelerate the reaction speed of the liquid crystal can effectively improve the phenomenon of dynamic image sticking of the liquid crystal display.

Since the operation of the overdrive needs to consider the data in the previous frame, the conventional technique generally uses a buffer memory to store the previous frame data to compare with a current frame data to calculate the required Drive voltage. However, it will reduce the size of the buffer memory. The data in the previous frame will be compressed first, and then decompressed to be restored to the original previous frame when it needs to be used, but as a result, the restored before A frame of data may cause errors in pixel values due to the compression/decompression process, which in turn affects the resulting overdrive values. Therefore, how to ensure the correctness of the overdrive value at the same time in the case of reducing the size of the buffer memory is an important issue.

SUMMARY OF THE INVENTION One object of the present invention is to provide an overdrive device for use in a display that avoids compression errors and causes erroneous overdrive values, and can also reliably reduce the size of the buffer memory to solve the above problems.

According to an embodiment of the present invention, an overdrive device applied to a display includes a compression unit, a storage unit, a first decompression unit, a comparison unit, a second decompression unit, and an overdrive value generating unit. The compression unit is configured to compress a previous frame data to generate a compressed previous frame data; the storage unit is coupled to the compression unit, and configured to store the compressed previous frame data; The decompression unit is coupled to the compression unit, and is configured to decompress the compressed previous frame data to generate a first decompressed previous frame data; the comparison unit is coupled to the first decompression unit, And comparing the difference between the previous frame data and the first decompressed previous frame data to generate a plurality of comparison results, wherein the plurality of comparison results are used to represent pixels in a current frame data. Whether the driving operation is performed; the second decompression unit is coupled to the storage unit, and is configured to decompress the compressed previous frame data to generate a second decompressed previous frame data; After the overdrive value generating unit is coupled to the second decompression unit, and for receiving the current frame data, the second decompression The previous frame data and the plurality of comparison results determine the overdrive value of each pixel in the current frame data.

According to another embodiment of the present invention, an overdrive method applied to a display includes: compressing a previous frame data to generate a compressed previous frame data; providing a storage unit to store the compressed previous image Box data; decompressing the compressed previous frame data to generate a first decompressed previous frame data; comparing the difference between the previous frame data and the first decompressed previous frame data And generating a plurality of comparison results, wherein the plurality of comparison results are used to indicate whether a pixel in the current frame data is to be driven; and decompressing the compressed previous frame data to generate a second decompressed front a frame data; and receiving the current frame data, the second decompressed previous frame data, and the plurality of comparison results to determine an overdrive value of each pixel in the current frame data.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of an overdrive device 100 applied to a display according to an embodiment of the invention. As shown in FIG. 1 , the overdrive device 100 includes a compression unit 110 , a storage unit (in the present embodiment, the storage unit is a memory 120), a first decompression unit 130, and a comparison unit 140. A second decompression unit 150 and an overdrive value generating unit 160. In the embodiment, the overdrive device 100 is disposed in a timing controller in a liquid crystal display.

In the operation of the overdrive device 100, first, the compression unit 110 receives and blocks the previous frame data D _{in_FN- in} units of blocks (one block may contain a plurality of pixels, for example, 16 pixels as a block). ₁ compresses to generate a compressed previous frame data D in — _c , and stores the compressed previous frame data D in — _c into the memory 120. At the same time, the compressed previous frame data D _{in_c} is also sent to the first decompression unit 130 for decompression operation to obtain a first decompressed previous frame data D in — _d1 , and then the comparison unit 140 compares the previous figure. data block _{D in_FN-1} and the difference between the previous frame compressed data _D in_d1 first solution to produce a plurality Flag comparison result, in this embodiment, are each of a single comparison result Flag bit values, And corresponds to a block of the previous frame data D _{in_FN-1} .

For an example of the operation of the comparison unit 140, please refer to FIG. 2 and FIG. 3, FIG. 2 is a flow chart of the comparison unit 140 generating a comparison result corresponding to one block, and FIG. 3 is a comparison of the previous frame data D. A schematic diagram of an example of _{in_FN-1} and the first frame data D _{in_d1} after the first decompression. Referring to FIG. 2, first, in step 202, for the same block of the previous frame data D _{in_FN-1} and the first frame data D _{in_d1} after the first decompression, the first pixel of the block is calculated. The error value after compression (that is, comparing the difference between the gray level value of the first pixel in the previous frame data D _{in_FN-1} and the first frame data D _{in_d1} after the first decompression) to generate a gray scale error value P_error, for example, referring to FIG. 3, the grayscale error value P_error of the first pixel is |50-59|=9. Next, in step 204, it is determined whether the grayscale error value P_error of the first pixel is greater than a first threshold Th1, and if so, the flow proceeds to step 206 to add a count value Count to "1"; if not, the flow Proceeding to step 208, the count value Count maintains the original value. Then, the process proceeds to step 210 to sequentially compare the grayscale error values of the 16 pixels shown in FIG. 3, and the count value Count at this time indicates that the grayscale error value of the pixel in the block is greater than the first critical value Th1. For the number of pixels, taking the third figure as an example, assuming that the value of the first threshold Th1 is "8", since the grayscale error value of the first, fifteenth, and 16th pixels is greater than "8", the count value at this time Count is equal to "3".

Next, in step 212, it is determined whether the count value Count is greater than a second threshold value Th2, and if so, the flow proceeds to step 214 to set the corresponding comparison result Flag to "0"; if not, the flow proceeds to step 216 to The corresponding comparison result Flag is set to "1", wherein "Flag=0" is used to indicate that all the pixels in the block are not driven in the subsequent processing, and "Flag=1" is used to indicate the All pixels in the block are driven in subsequent processing. For example, taking FIG. 3 as an example, assuming that the value of the second threshold Th2 is "4", since the count value Count (its value is equal to 3) is less than "4", the comparison result Flag is set to "1". "To indicate that all pixels in the block have to be driven in subsequent processing.

After the comparison unit 140 processes all the blocks of the previous frame data D in — _FN-1 , the comparison unit 140 stores the comparison result Flag corresponding to all the blocks of the previous frame data D in — _FN − ₁ to the memory 120 . in.

Next, returning to the overdrive device 100 shown in FIG. 1 , the second decompression unit 150 reads the compressed previous frame data D in — _c and the comparison result Flag from the memory, and compresses the previous frame data. After D _{in_c is} decompressed, the second decompressed previous frame data D in — _{d2 is generated} , and the second decompressed previous frame data D in — _d2 is transmitted to the overdrive value generating unit 160 together with the comparison result Flag. The overdrive value generating unit 160 receives a current frame data D in — _FN , a second decompressed previous frame data D in — _{d2 ,} and a comparison result Flag to determine an overdrive value of each pixel in the current frame data D in — _FN . For example, if the current value of the previous frame information D corresponding to the same block one _{in_d2} comparison result Flag is "1", the overdrive value generating unit 160 will be frame data after the second decompression _D in_FN All the pixels in the block are overdriven to output an overdrive value D _OD corresponding to each pixel; otherwise, the current frame data D _{in_FN} and the second decompressed previous frame data D _{in_d2 are assumed} . If the value of the comparison result Flag corresponding to the block is "0", the overdrive value generating unit 160 does not overdrive the pixel in the block, that is, the pixel in the block of the current frame data D _{in_FN} The original grayscale value is output as an overdrive value D _OD to the back end circuit.

As described above, the overdrive device of the present invention stops the operation of subsequently generating the overdrive value for the block having a large compression/decompression error, so that the compression/decompression error can be avoided as much as possible, resulting in an erroneous overdrive value. . In addition, since only one bit (ie, the comparison result Flag) is required for one block of the frame data to indicate whether the block needs to be driven, the usage of the memory 120 can also be reduced to reduce manufacturing. cost.

It should be noted that, in the foregoing embodiment, the comparison result Flag is first stored in the memory 120 and then transmitted to the overdrive value generating unit 160 via the second decompression unit 150. However, in other embodiments of the present invention, Comparison result Flag can be directly driven value The generating unit 160 reads or transmits to the overdrive value generating unit 160 via other paths, and these design changes are all within the scope of the present invention.

Please refer to FIG. 4, which is a flow chart of an overdrive method applied to a display according to an embodiment of the invention. Referring to Figures 1 and 4, the process is as follows: Step 400: compressing a previous frame data to generate a compressed previous frame data; Step 402: providing a storage unit to store the compressed previous frame data; Step 404: Decompress the compressed previous frame data to generate a first decompressed previous frame data; Step 406: Compare the previous frame data with the first decompressed previous frame data. The difference between the plurality of comparison results to generate a plurality of comparison results, wherein the plurality of comparison results are used to indicate whether a pixel in the current frame data is to be driven; and step 408: decompressing the compressed previous frame data to generate a After the second decompressed, the previous frame data is obtained; Step 410: receiving the current frame data, the second decompressed previous frame data, and the plurality of comparison results to determine each of the current frame materials The overdrive value of the pixel.

Briefly summarized in the present invention, in the overdrive device and related method of the present invention, it is possible to first determine the correctness of the data after compression/decompression of the previous frame data to determine whether or not to perform an overdrive operation in subsequent operations. Therefore, it is possible to avoid the compression/decompression error and cause an erroneous overdrive value, which in turn affects the display quality. Further, the present invention The steps of compressing, decompressing, and judging the correctness of the data are all performed in units of blocks, so that the amount of memory used can be effectively reduced, and the manufacturing cost can be reduced.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100‧‧‧Overdrive

110‧‧‧Compression unit

120‧‧‧ memory

130‧‧‧First decompression unit

140‧‧‧Comparative unit

150‧‧‧Second decompression unit

160‧‧‧Overdrive value generating unit

202~216, 400~410‧‧‧ steps

1 is a schematic diagram of an overdrive device applied to a display in accordance with an embodiment of the present invention.

Figure 2 is a flow chart showing the comparison result of the comparison unit corresponding to a block.

Figure 3 is a schematic diagram showing an example of comparing the previous frame data with the data of the previous frame after the first decompression.

4 is a flow chart of an overdrive method applied to a display in accordance with an embodiment of the present invention.

100‧‧‧Overdrive

110‧‧‧Compression unit

120‧‧‧ memory

130‧‧‧First decompression unit

140‧‧‧Comparative unit

150‧‧‧Second decompression unit

160‧‧‧Overdrive value generating unit

Claims (4)

An overdrive device for a display, comprising: a compression unit for compressing a previous frame data to generate a compressed previous frame data; a storage unit coupled to the compression unit for Storing the compressed data of the previous frame; a first decompression unit coupled to the compression unit for decompressing the compressed previous frame data to generate a first decompressed previous frame data; a comparison unit, coupled to the first decompression unit, for comparing a difference between the previous frame data and the first decompressed previous frame data to generate a plurality of comparison results, wherein the plurality of comparison results The comparison result is used to indicate whether a pixel in the current frame data is to be driven. A second decompression unit is coupled to the storage unit to decompress the compressed previous frame data to generate a first And the second decompression unit is configured to receive the current frame data, the second decompressed previous frame data, and the second decompressed unit Multiple comparisons In order to determine an overdrive value of each pixel in the current frame data; wherein the compression unit compresses the previous frame data in units of blocks, for the previous frame data and the solution After compressing each block of the previous frame data, the comparing unit compares the block of the previous frame data with the pixel value of the block of the previous frame data after the decompression is greater than a first threshold a number of pixels of the value to produce the comparison result, wherein when the number of pixels is greater than a second threshold, the comparison result indicates that the pixel in the block of the current frame data is not overdriven; and when the number of pixels is not greater than the second threshold, the comparison result is represented The pixels in the block of the current frame data need to be driven. The overdrive device of claim 1, wherein each of the plurality of comparison results is a single bit value and is stored in the storage unit. An overdrive method applied to a display, comprising: compressing a previous frame data to generate a compressed previous frame data; providing a storage unit to store the compressed previous frame data; decompressing the compression The previous frame data is used to generate a first decompressed previous frame data; comparing the difference between the previous frame data and the first decompressed previous frame data to generate a plurality of comparison results, The plurality of comparison results are used to indicate whether a pixel in the current frame data is to be driven; the compressed previous frame data is decompressed to generate a second decompressed previous frame data; and receiving The current frame data, the second decompressed previous frame data, and the plurality of comparison results to determine an overdrive value of each pixel in the current frame data; wherein the previous frame data is compressed The step of generating the data of the previous frame after the compression The method includes: compressing the previous frame data in units of blocks to generate the compressed previous frame data; and comparing between the previous frame data and the decompressed previous frame data The step of generating the plurality of comparison results includes: determining, for each block of the previous frame data and the decompressed previous frame data, the block and the solution of the previous frame data. After the compression, the pixel value difference in the block of the previous frame data is greater than a pixel number of a first threshold value to generate the comparison result; when the number of pixels is greater than a second threshold value, the comparison result is Representing that the pixel in the block of the current frame data is not overdriven; and when the number of pixels is not greater than the second threshold, the comparison result indicates that the current frame data is within the block The pixel needs to be driven. The overdrive method of claim 36, wherein each of the plurality of comparison results is a single bit value and is stored in the storage unit.