TWI406215B - Overdriving method and overdriving circuit - Google Patents

Abstract

The present invention relates to an overdriving method and an overdriving circuit realizing the overdriving method. The overdriving circuit includes a dispose circuit, and the dispose circuit includes a look-up table. A previous frame data and a current frame data are all inputted into the dispose circuit. An emendation gray data of each pixel can obtained by combining an interpolation method and the look-up table. When all the pixels's gray data are emendated, the dispose circuit outputs an emendation frame data. When the gray data of a pixel of the previous frame data is equal to the gray data of the corresponding pixel of the current frame data, an emendation gray data of the corresponding pixel is equal to the gray data of a pixel of the previous frame data.

Description

Overdrive method and overdrive circuit

The present invention relates to an overdrive method and an overdrive circuit implementing the overdrive method.

The image display by the liquid crystal display device is mainly realized by a plurality of pixels arranged in a matrix. The external data signal is processed by the driving circuit of the liquid crystal display device, and the driving circuit applies different data signals to the pixels to deflect the liquid crystal molecules of the pixels to different angles, and the deflection angle of the liquid crystal molecules determines the light transmittance of the corresponding pixels. The amount is such that the brightness of the three primary colors displayed by each pixel is different, and the three primary colors of different brightness are mixed in space, and the human eye sees a colorful picture. Generally, the response of the liquid crystal molecules to the loaded real-time changing data signal is very slow, and thus, image sticking occurs when the liquid crystal display device displays a moving image. In order to reduce or suppress this phenomenon, the industry has developed overdrive technology.

Please refer to FIG. 1, which is a circuit block diagram of a prior art overdrive circuit. The overdrive circuit 10 includes a memory 11 and a processing circuit 12 for storing a previous frame of data signals. The processing circuit 12 includes a look-up table (see Table 1). The current frame data signal and the previous frame data signal are simultaneously input to the processing circuit 12, and the processing circuit 12 determines a corresponding correction data signal according to the stored comparison table and outputs the corresponding correction data signal to the driving circuit.

Please refer to Table 1 below. Table 1 is a comparison table stored in the processing circuit of Figure 1. The comparison table shown in Table 1 is that the data signal is 256-step gray scale. In the case of the first column of the comparison table, the initial grayscale value, that is, the grayscale value of each pixel of the data signal of the previous frame in FIG. 1, a total of 256; the first row of the comparison table represents the target grayscale value, That is, there are 256 grayscale values of each pixel of the current frame data signal in FIG. 1, and the grayscale value of each pixel of the corrected data signal in FIG. 1 is 256*256 at the intersection of the initial grayscale value and the target grayscale value. One. For example, when the data signal of a certain pixel changes from 0 gray scale of the previous frame to 252 gray scale of the current frame, the corrected data signal of the pixel is 255 gray scale; the data signal of a certain pixel changes from the 254 gray scale of the previous frame. When the 5th gray level of the current frame is reached, the corrected data signal of the pixel is 0 gray scale. It can be seen that, according to the comparison table, the corrected data signal of each data signal of each pixel from any starting grayscale value to any target grayscale value can be determined.

However, the overdrive circuit 10 requires a large-capacity memory to store the look-up table, so the cost of the overdrive circuit 10 is high. To this end, the industry has developed another overdrive technology that uses an interpolation operation. The method combines a simplified comparison table (as shown in Table 2) to restore the original control table (ie, the comparison table shown in Table 1).

Please refer to Table 2 below, which is a simplified comparison table of prior art. The simplified comparison table shown in Table 2 is still the case where the data signal is 256-step gray scale. The first column of the simplified comparison table indicates the starting grayscale value, that is, the grayscale value of each pixel of the previous frame data signal in FIG. There are 17 in total, 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 255; the first row of the comparison table represents the target grayscale The value, that is, the grayscale value of each pixel of the previous frame data signal in FIG. 1 is 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 255, a total of 17; the intersection of the starting grayscale value and the target grayscale value, that is, the partial grayscale value of the corrected data signal in Fig. 1, a total of 17*17. Therefore, the simplified comparison table stores only about 1/15 of the original comparison table, so the amount of storage of the overdrive circuit employed by the overdrive technique is correspondingly reduced.

The interpolation operation method is as follows and the following formula:

X ₁ =[(BA)/(G ₃ -G ₁ )]*(G ₂ -G ₁ )+A

X ₃ =[(DC)/(G ₃ -G ₁ )]*(G ₂ -G ₁ )+C

X ₂ =[(X ₃ -X ₁ )/(G ₆ -G ₄ )]*(G ₅ -G ₄ )+X ₁

X ₂ ^' =[(CA)/(G ₆ -G ₄ )]*(G ₅ -G ₄ )+A

X ₂ ^" =[(DB)/(G ₆ -G ₄ )]*(G ₅ -G ₄ )+B

Where G ₁ , G ₃ , G ₄ , G ₆ , A, B, C, D are known quantities in the simplified comparison table, G ₂ is an arbitrary gray level value between G ₁ and G ₃ , and G ₅ is Any gray scale value between G ₄ and G ₆ , X ₁ , X ₂ , X ₃ , X ₂ ^' , X ₂ ^" is an unknown amount, thereby restoring the original comparison table.

Please refer to Table 3 below. The third table is the part of the comparison table restored by the prior art interpolation method combined with the simplified comparison table shown in Table 2. For example, when G ₁ =16, G ₂ =17, G ₃ =32, G ₄ =16, G ₅ =17, G ₆ =32, A=16, B=2, C=100, D=32, It can be calculated that X ₁ =15, X ₂ =19, X ₃ =94; when G ₂ =24, G ₅ =30, when other values are constant, X ₁ =0, X ₂ =46, X ₃ can be calculated. =54.

However, the interpolation operation method is based on the known quantities A, B, C, and D in the simplified comparison table. When the B or C is too large or too small, the simplified calculation is combined by the interpolation operation method. The table returned by the table is An error occurs where the starting grayscale value is the same as the target grayscale value. For example, the initial grayscale value is 20, the target grayscale value is 20, and the overdrive value restored by the interpolation operation method is 24, and the actual required overdrive value is 20. Therefore, the liquid crystal display device using the interpolation method in combination with the overdrive method of the simplified comparison table still has a problem that the display quality is not high.

In view of the above, it is necessary to provide an overdrive method capable of effectively improving the display quality of a liquid crystal display device.

At the same time, it is necessary to provide an overdrive circuit that implements the overdrive method.

An overdrive method, the overdrive circuit for implementing the overdrive method includes a processing circuit, the processing circuit includes a lookup table, the overdrive method includes the following steps: a. The current frame data signal and the previous frame data signal are simultaneously input to The processing circuit; b. combining the comparison table by an interpolation operation method Calculating a corrected grayscale value of each pixel, wherein when the grayscale value of any pixel of the previous frame data signal is equal to the grayscale value of the corresponding pixel of the current frame, the corrected grayscale value of the pixel is equal to The grayscale value of the current frame; c. The processing circuit outputs a frame corrected data signal after the grayscale values of all the pixels are corrected.

An overdrive circuit includes a processing circuit, the processing circuit includes a look-up table, and the current frame data signal and the previous frame data signal are simultaneously input to the processing circuit, and the corrected gray scale value of each pixel can be used by An interpolation operation method is combined with the comparison table to calculate that after the gray scale values of all the pixels are corrected, the processing circuit outputs a frame corrected data signal, wherein, when the gray level value of any pixel of the previous frame data signal is When the grayscale value of the corresponding pixel of the current frame is equal to the grayscale value of the pixel, the corrected grayscale value of the pixel is equal to the grayscale value of the current frame.

Compared with the prior art, the interpolation operation method adopted by the overdrive method of the present invention first determines that the corrected gray scale value at which the initial gray scale value is the same as the target gray scale value is equal to the initial gray scale value, and therefore, the present invention The interpolation method used in the overdrive method and the original comparison table restored by the simplified comparison table are consistent with the overdrive value of the actual required overdrive value at the same starting grayscale value and the target grayscale value, thereby improving the The display quality of the liquid crystal display device using the overdrive method.

The overdrive circuit of the present invention has the above-mentioned advantageous effects.

Please refer to FIG. 2, which is a circuit block diagram of a liquid crystal display device using the overdrive method of the present invention. The liquid crystal display device 200 includes an overdrive circuit The circuit 20, a driving circuit 24 and a liquid crystal display panel 25, the liquid crystal display panel 25 includes a plurality of pixels 26 arranged in a matrix. The external data signal is input to the overdrive circuit 20, and the overdrive circuit 20 corrects the data signal. The drive circuit 24 processes the corrected data signal and applies different data to each pixel 26 of the liquid crystal display panel 25. The signals are such that the liquid crystal molecules of the pixels 26 are deflected at different angles, and the deflection angle of the liquid crystal molecules determines the amount of light transmitted by the corresponding pixels 26, so that the brightness of the three primary colors displayed by the pixels 26 is different, and the three primary colors with different brightness are mixed in space. The human eye saw a colorful picture.

Please refer to FIG. 3, which is a circuit block diagram of the overdrive circuit shown in FIG. 2. The overdrive circuit 20 includes a memory 21 and a processing circuit 22 for storing a previous frame of data signals. The processing circuit includes a simplified comparison table, as shown in Table 4 below. In order to facilitate comparison with the prior art, the case where the data signal is 256-step gray scale is still taken as an example for description. The first column of the simplified comparison table represents the starting gray level, that is, the grayscale values of the pixels of the previous frame data signal in FIG. 3 are 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 255, a total of 17; the first row of the simplified comparison table represents the target grayscale, that is, the grayscale value of each pixel of the current frame data signal in FIG. 3 is 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 255, a total of 17; the initial grayscale value and the target grayscale value intersection, that is, in Figure 3 Corrected some of the grayscale values of the data signal, a total of 17 * 17. The corrected grayscale value at which the starting grayscale value is the same as the target grayscale value is equal to the starting grayscale value.

The current frame data signal and the previous frame data signal are simultaneously input to the processing circuit 22. The processing circuit 22 calculates a corresponding correction data signal and outputs the data according to the input data signal by using a new interpolation operation method and the simplified comparison table. .

It is assumed that the previous frame data signals in _a gray scale value of the pixel P G _2, P pixel gray level value of ₂ G _3, current frame data signals in _a gray scale value of the pixel P G _3, P ₂ of the pixel grayscale value G _2, wherein the pixel P _1, P ₂ and grayscale value G _2, G ₃ is selected, an arbitrary nature. Then, the calculation process of the corrected gray scale values X ₄ and X ₃ of the pixels P ₁ , P ₂ is as follows:

a. Provide a blank comparison table. The blank comparison table is borrowed for a clearer explanation of the calculation process and does not actually exist. The first column of the blank comparison table represents the starting grayscale value, that is, the grayscale value of each pixel of the data signal of the previous frame in FIG. 3; the first row of the blanking comparison table represents the target grayscale value, that is, the current value in FIG. The grayscale value of each pixel of the frame data signal; the grayscale value of each pixel of the corrected data signal in FIG. 3 at the intersection of the initial grayscale value and the target grayscale value. The structure of any part of the blank comparison table is shown in the following table:

b. Fill in the first row and the first column with the grayscale values G ₁ and G _{4 of the} simplified comparison table shown in Table ₄ , where G _{1 is} smaller than G ₂ and G _{4 is} greater than G ₃ . Meanwhile, the initial grayscale value G ₁ to the grayscale values of the corrected target gray level G ₁ A, G ₄ initial grayscale value of the grayscale values to the correction target grayscale value G ₁ B, starting gray The corrected gray scale value C of the value G ₁ to the target gray scale value G ₄ , the corrected gray scale value G _{4 of} the target gray scale value G ₄ to the target gray scale value G ₄ can be obtained from the simplified comparison table shown in Table 4 Directly obtained in the middle, also filled in the blank comparison table, as shown below:

Where A=G ₁ and D=G ₄ .

c. Fill the starting gray level value of the same gray level in the initial grayscale value and the target value of the same local gray level, i.e., the starting gray level correction value G ₂ G ₂ to the target gray value of a gray scale value E = G _2, G ₃ initial grayscale value G to the corrected gray level value of the target ₃ grayscale value F = G _3. At the same time, it is assumed that the corrected gray scale value of the starting gray scale value G ₄ to the target gray scale value G ₂ is X ₁ , and the corrected gray scale value of the starting gray scale value G ₄ to the target gray scale value G ₃ is X ₁ ^' , G ₃ initial grayscale value of the grayscale values to the correction target grayscale value G ₁ X ₂ ^', _a corrected initial grayscale gray value G ₂ G grayscale value to the target value X ₂ ^" starting grayscale value G grayscale value G of the _{target. 1} to the corrected gray level value of ₃ X _{3, G. 1} starting grayscale values of the grayscale values to the corrected target value of the gray scale G ₂ X ₃ ^', ₂ initial grayscale value G to the corrected target value of the gray level value of the gray scale G ₄ X ₄ ^', the initial grayscale value G ₃ G grayscale value to the target correction value of the gray scale ₄ X ₄ ^", As shown in the following table:

d. The values of the unknown quantities X ₁ , X ₂ , X ₃ , X ₄ , X ₁ ^' , X ₂ ^' , X ₂ ^" , X ₃ ^' , X ₄ ^' , X ₄ ^" are interpolated by the following formula (1) Calculated to (10): X ₁ =[(DB)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+B (1)

X ₂ =[(X ₁ -E)/(G ₄ -G ₂ )]*(G ₃ -G ₂ )+E (2)

X ₃ =[(CA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+A (3)

X ₄ =[(FX ₃ )/(G ₃ -G ₁ )]*(G ₂ -G ₁ )+X ₃ (4)

X ₁ ^' =[(DB)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+B (5)

X ₂ ^' =[(BA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+A (6)

X ₂ ^'' =[(BA)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+A (7)

X ₃ ^' =[(CA)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+A (8)

X ₄ ^' =[(DC)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+C (9)

X ₄ ^" =[(DC)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+C (10)

Wherein, the calculations of X ₁ , X ₂ , X ₃ , X ₄ , X ₁ ^' , X ₂ ^' , X ₂ ^" , X ₃ ^' , X ₄ ^' , X ₄ ^" all relate to A, E, F, D These four parameters are calculated based on the corrected grayscale values of the starting grayscale value and the target grayscale value.

The selection of the gray scale values G ₂ and G ₃ described above is arbitrary. Therefore, the above calculation method can be used to calculate the corrected data signal of the data signal of each pixel from any starting gray scale value to any target gray scale value.

According to the above calculation method, the working principle of the processing circuit 22 can be summarized as follows: the current frame data signal and the previous frame data signal are simultaneously input to the processing circuit 22. The corrected data signal of each pixel can be calculated by the interpolation operation formulas (1) to (10). After the data signal correction of all the pixels is completed, the processing circuit 22 outputs a frame corrected data signal.

Please refer to Table 5 below. Table 5 is the part of the original comparison table restored by the interpolation method used in the overdrive method of the present invention. For example, when G ₁ =16, G ₂ =20, G ₃ =27, G ₄ =32, it can be determined that A=16, B=2, C=100, D=32, E=20, F=27, X ₁ =10, X ₂ =14, X ₃ =74, X ₄ =57, X ₁ ^' =23, X ₂ ^' =6, X ₂ ^" = can be calculated from the interpolation operation formulas (1) to (4). 12. X ₃ ^' = 37, X ₄ ^' = 83, X ₄ ^" = 53. In the original comparison table, when the starting grayscale value is 20 and the target grayscale value is 20, the overdrive value restored by the interpolation operation method is 20; when the initial grayscale value is 21, the target gray is When the order value is 20, the overdrive value restored by the interpolation operation method is 19. That is, it matches the actual overdrive value required.

Compared with the prior art, the interpolation operation method adopted by the overdrive method of the present invention first determines that the corrected grayscale value at the same starting grayscale value and the target grayscale value is equal to the initial grayscale value, and the starting gray The corrected grayscale value at which the step value and the target grayscale value change are small is calculated based on the corrected grayscale value at which the initial grayscale value is the same as the target grayscale value. Therefore, the interpolation operation method used in the overdrive method of the present invention and the original comparison table restored by the simplified comparison table have overdrive values and actual needs in the place where the initial grayscale value is the same as or smaller than the target grayscale value. The overdrive value matches, which improves the mining The display quality of the liquid crystal display device using the overdrive method.

In summary, the present invention has indeed met the requirements of the invention, and has filed a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make equivalent modifications or changes in accordance with the spirit of the present invention. It should be covered by the following patent application.

10, 20‧‧‧Overdrive circuit

11, 21‧‧‧ memory

12, 22‧‧‧ processing circuit

200‧‧‧Liquid crystal display device

24‧‧‧Drive Circuit

25‧‧‧LCD panel

26‧‧‧ pixels

1 is a block diagram of a circuit of a prior art overdrive circuit.

Figure 2 is a circuit block diagram of a liquid crystal display device employing the overdrive method of the present invention.

Figure 3 is a circuit block diagram of the overdrive circuit shown in Figure 2.

20‧‧‧Overdrive circuit

21‧‧‧ memory

22‧‧‧Processing Circuit

Claims (9)

An overdrive method, the overdrive circuit for implementing the overdrive method includes a processing circuit, the processing circuit includes a lookup table, the overdrive method includes the following steps: a. The current frame data signal and the previous frame data signal are simultaneously input to The processing circuit; b. The corrected gray scale value of each pixel is calculated by an interpolation operation method combined with the comparison table, wherein when the gray level value of any pixel of the previous frame data signal is equal to the current frame The grayscale value of the corresponding pixel is equal to the grayscale value of the current frame; c. the grayscale value of all the pixels is corrected, and the processing circuit outputs a frame corrected data signal, wherein the The interpolation operation method includes interpolation equations (1) to (10): X ₁ = [(DB) / (G _{4 -} G ₁ )] * (G _{2 -} G ₁ ) + B (1) X ₂ = [( X ₁ -E)/(G ₄ -G ₂ )]*(G ₃ -G ₂ )+E (2) X ₃ =[(CA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ ) +A (3) X ₄ =[(FX ₃ )/(G ₃ -G ₁ )]*(G ₂ -G ₁ )+X ₃ (4) X ₁ ^' =[(DB)/(G ₄ - G ₁ )]**(G ₃ -G ₁ )+B (5) X ₂ ^' =[(BA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+A (6) X ₂ ^" =[(BA)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+A (7) X ₃ ^' =[(CA)/(G ₄ -G ₁ ) ]*(G ₂ -G ₁ )+A (8) X ₄ ^' =[(DC)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+C (9) X ₄ ^" =[( DC)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+C (10) The relationship between the parameters in the interpolation equations (1) to (10) is as shown in Table (1): Wherein the table (a) represents the starting column of the first gray level value, the first row indicates the target gray value, the initial value and the target gray value at the intersection of the gray scale represented by the corrected grayscale value, G _1, G ₄ , A, B, C, D are the known quantities in the comparison table, and A = G ₁ , D = G ₄ , G ₂ , G ₃ are any gray scale values between G ₁ and G ₄ , E = G ₂ , F=G ₃ , X ₁ , X ₂ , X ₃ , X ₄ , X ₁ ^' , X ₂ ^' , X ₂ ^" , X ₃ ^' , X ₄ ^' , X ₄ ^" are unknown. The overdrive method of claim 1, wherein the comparison table is a simplified comparison table. The overdrive method of claim 2, wherein the first column of the simplified comparison table represents a starting gray scale, and the first row of the simplified comparison table represents a target gray scale. The overdrive method of claim 3, wherein the first column of the simplified comparison table has a grayscale value of 17, and the first row of the simplified comparison table has a grayscale value of 17. The overdrive method of claim 4, wherein the current frame data signal is 256-step gray scale. The overdrive method of claim 5, wherein the grayscale value of the first column of the simplified comparison table is 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160 176, 192, 208, 224, 240, 255, the grayscale values of the first row of the simplified comparison table are 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240, 255. The overdrive method of claim 1, wherein the overdrive circuit further comprises a memory for storing a previous frame of data signals. An overdrive circuit includes a processing circuit, the processing circuit includes a look-up table, and the current frame data signal and the previous frame data signal are simultaneously input to the processing circuit, and the corrected gray scale value of each pixel can be used by An interpolation operation method is combined with the comparison table to calculate that after the gray scale values of all the pixels are corrected, the processing circuit outputs a frame corrected data signal, wherein, when the gray level value of any pixel of the previous frame data signal is equal to the current value of the corresponding pixel in frame grayscale correction grayscale value of the pixel gray level value is equal to the current frame, wherein the interpolation comprises an interpolation arithmetic method arithmetic expressions (1) to (10): X ₁ =[(DB)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+B (1) X ₂ =[(X ₁ -E)/(G ₄ -G ₂ )]*(G ₃ -G ₂ )+E (2) X ₃ =[(CA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+A (3) X ₄ =[(FX ₃ )/(G ₃ -G ₁ )]*(G ₂ -G ₁ )+X ₃ (4) X ₁ ^' =[(DB)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+B (5) X ₂ ^' =[(BA)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+A (6) X ₂ ^" =[(BA)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+A (7) X ₃ ^' =[(CA)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+A (8) X ₄ ^' =[(DC)/(G ₄ -G ₁ )]*(G ₂ -G ₁ )+C (9) X ₄ ^" =[(DC)/(G ₄ -G ₁ )]*(G ₃ -G ₁ )+C (10) The relationship between the parameters in the interpolation formulas (1) to (10) is as shown in the table (1) ) shown: Wherein the table (a) represents the starting column of the first gray level value, the first row indicates the target gray value, the initial value and the target gray value at the intersection of the gray scale represented by the corrected grayscale value, G _1, G ₄ , A, B, C, D are the known quantities in the comparison table, and A = G ₁ , D = G ₄ , G ₂ , G ₃ are any gray scale values between G ₁ and G ₄ , E = G ₂ , F=G ₃ , X ₁ , X ₂ , X ₃ , X ₄ , X ₁ ^' , X ₂ ^' , X ₂ ^" , X ₃ ^' , X ₄ ^' , X ₄ ^" are unknown. The overdrive circuit of claim 8, wherein the overdrive circuit further comprises a memory for storing a previous frame of data signals.