TWI459347B - Method of driving a liquid crystal display - Google Patents

Description

Method of driving a liquid crystal display

The present invention relates to a method for driving a liquid crystal display, and more particularly to using an integrated driving circuit to adjust an initial setting value of a register in an integrated driving circuit to make the brightness of the first half plane of the liquid crystal panel and the second half A method of driving a liquid crystal display with the same brightness of a plane.

The integrated driving circuit applied to the small-sized liquid crystal panel includes a timing controller, a source driving circuit, a gate driving circuit, and a DC/DC converter, wherein the integrated driving circuit can be modified. The initial code in the register controls the output of the integrated driver circuit.

Referring to FIG. 1 and FIG. 2, FIG. 1 is a schematic view illustrating a liquid crystal display 100, and FIG. 2 is a schematic view illustrating a difference in luminance between a left half plane and a right half plane of the liquid crystal panel 102 due to process factors. The liquid crystal display 100 includes a liquid crystal panel 102, an integrated driving circuit 104, 240 gate lines G1-G240, and 960 source lines S1-S960. The liquid crystal panel 102 is a twisted nematic (TN). A liquid crystal panel, a Super Twisted Nematic (STN) panel or a Thin Film Transistor Liquid Crystal Display (TFT-LCD). As shown in FIG. 1, the integrated drive circuit 104 outputs the material voltage to the left half plane of the liquid crystal panel 102 using the source lines S1-S480, and the source lines S481-S960 output the data voltage to the right half plane of the liquid crystal panel 102. As shown in FIG. 2, the trace impedance of the source lines S1-S480 corresponding to the left half plane of the liquid crystal panel 102 is large and the source corresponding to the right half plane of the liquid crystal panel 102 is large due to the process factors of the liquid crystal panel. The trace impedance of the lines S481-S960 is small, resulting in the brightness of the left half plane of the liquid crystal panel 102 being higher than that of the right half plane. Please refer to FIG. 3 , which is a diagram illustrating that the actual voltage of the pixel in the left half plane of the liquid crystal panel 102 is not equal to the data voltage of the pixel originally set to be output to the left half plane of the liquid crystal panel 102 by the integrated driving circuit 104 . schematic diagram. When the common voltage of the liquid crystal panel 102 is positive, since the trace impedance corresponding to the source lines S1-S480 of the left half plane of the liquid crystal panel 102 is relatively large, the actual pixel of the left half plane of the liquid crystal panel 102 will be caused. The voltage VT is lower than the data voltage VR of the pixel that is originally set to be output to the left half plane of the liquid crystal panel 102 (the left half plane of the liquid crystal panel 102 is brighter than the right half plane of the liquid crystal panel 102); When the common voltage of the panel 102 is negative polarity, since the trace impedance corresponding to the source lines S1-S480 of the left half plane of the liquid crystal panel 102 is relatively large, the actual voltage VT of the pixel in the left half plane of the liquid crystal panel 102 will be caused. The data voltage VR of the pixel which is originally set to be output to the left half plane of the liquid crystal panel 102 is lower than the integrated driving circuit 104 (the left half plane of the liquid crystal panel 102 is darker than the right half plane of the liquid crystal panel 102). However, regardless of whether the common voltage of the liquid crystal panel 102 is positive or negative, the right half plane of the liquid crystal panel 102 has no such phenomenon. As such, the brightness of the left half plane and the right half plane of the liquid crystal panel 102 may be uneven, causing a block phenomenon.

The present invention relates to a method of driving a liquid crystal display. The method includes comparing the brightness of the first half plane of the liquid crystal panel and the brightness of the second half plane of the liquid crystal panel according to an image data; when the brightness of the first half plane is not equal to the second half Adjusting the first image data corresponding to the first half plane of the image data to generate a new image data; the liquid crystal panel displays the next image according to the new image data; wherein the first half plane system It is a half-plane which is far away from the driving circuit in the liquid crystal panel.

The invention provides a method of driving a liquid crystal display. The method compares the brightness of the first half plane of the liquid crystal panel with the brightness of the second half plane by using an integrated driving circuit when a liquid crystal panel displays a picture according to an image data. Then, when the brightness of the first half plane of the liquid crystal panel is not equal to the brightness of the second half plane of the liquid crystal panel, the initial setting value of the register in the integrated driving circuit is adjusted to make the first panel of the liquid crystal panel The brightness of the half plane is the same as the brightness of the second half plane. As such, the present invention can solve the problem that the brightness of the first half plane of the liquid crystal panel is not equal to the brightness of the second half plane of the liquid crystal panel because the trace impedance of the plurality of source lines is different.

Please refer to FIG. 1 and FIG. 4, which is a flow chart illustrating a method of driving the liquid crystal display 100 according to an embodiment of the present invention. The method of FIG. 4 is illustrated by the liquid crystal display 100 of FIG. 1. The detailed steps are as follows: Step 400: Start; Step 402: Compare the first half plane of the liquid crystal panel 102 when the liquid crystal panel 102 displays a picture according to an image data. Whether the brightness is the same as the brightness of the second half plane; if not, proceeding to step 404; if yes, proceeding to step 408; step 404: when the brightness of the first half plane of the liquid crystal panel 102 is not equal to the second half plane of the liquid crystal panel 102 The first image data corresponding to the first half plane of the liquid crystal panel 102 is adjusted to generate a new image data. Step 406: The liquid crystal panel 102 displays the next image according to the new image data, and jumps back to step 402. Step 408: The integrated drive circuit 104 does not adjust the initial set value of the register 1042.

In step 402, when the liquid crystal panel 102 displays a picture according to the image data, the integrated driving circuit 104 compares the brightness of the first half plane of the liquid crystal panel 102 with the brightness of the second half plane. When the brightness of the first half plane of the liquid crystal panel 102 is the same as the brightness of the second half plane, the integrated driving circuit 104 does not adjust the initial setting value of the register 1042, and uses the initial setting value in the register 1042 at this time. The liquid crystal panel 102 is driven. In addition, the first half plane of the liquid crystal panel 102 is a half plane far from the integrated driving circuit 104 in the liquid crystal panel 102, and the liquid crystal panel 102 can be a twisted nematic (TN) panel, a super A Twisted Nematic (STN) panel or a Thin Film Transistor Liquid Crystal Display (TFT-LCD). In addition, the integrated driving circuit 104 includes a source driving circuit and a gate driving circuit, and the present invention is not limited to 240 gate lines G1-G240 and 960 source lines S1-S960. Referring to FIG. 5, FIG. 6, FIG. 7, and FIG. 8, FIG. 5 and FIG. 7 are diagrams for explaining that the first half of the liquid crystal panel 102 corresponds to when the common voltage of the liquid crystal panel 102 is positive. The grayscale value of the first image data of the plane is adjusted upward to be higher than the data voltage VR of the pixel originally outputted to the left half plane of the liquid crystal panel 102 by the integrated driving circuit 104, and FIGS. 6 and 8 are descriptions. When the common voltage of the liquid crystal panel 102 is negative polarity, the grayscale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 is adjusted downward to be output to the liquid crystal panel 102 than the integrated driving circuit 104 is originally set. A schematic diagram of the data voltage VR of the left half plane of the pixel. In step 404, as shown in FIG. 5, when the common voltage of the liquid crystal panel 102 is positive, the initial setting of the buffer 1042 in the integrated driving circuit 104 will correspond to the liquid crystal panel 102. The grayscale value of the first image data of the first half plane is adjusted upward by a same grayscale value, that is, the grayscale value of the first image data is uniformly adjusted upward regardless of the pixel position of the first half plane of the liquid crystal panel 102. The same grayscale value. As shown in FIG. 5, when the common voltage of the liquid crystal panel 102 is positive, the initial setting value of the register 1042 in the integrated driving circuit 104 is adjusted in advance, and corresponds to the liquid crystal panel 102. The grayscale value of the first image data of the first half plane is adjusted upward by the same grayscale value (in this case, the grayscale values of all the first image data correspond to the voltage V1), so the source passes through the left half plane of the liquid crystal panel 102. After the traces of the lines S1-S480, the grayscale values of the first image data corresponding to the first half plane of the liquid crystal panel 102 approach the data voltage VR. As shown in FIG. 6, when the common voltage of the liquid crystal panel 102 is negative, the initial setting value of the register 1042 in the integrated driving circuit 104 is adjusted to correspond to the first image of the first half plane of the liquid crystal panel 102. The grayscale value of the data is adjusted downward by the same grayscale value, that is, regardless of the pixel position of the first half plane of the liquid crystal panel 102, the grayscale values of the first image data are uniformly adjusted downward by the same grayscale value (this The gray scale values of all the first image data correspond to the voltage V2). Therefore, after the traces of the source lines S1-S480 of the left half plane of the liquid crystal panel 102, the gray scale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 approaches the data voltage VR. In addition, as shown in FIG. 7, in another embodiment of the present invention, when the common voltage of the liquid crystal panel 102 is positive, the initial setting value of the buffer 1042 in the integrated driving circuit 104 is adjusted to correspond to The grayscale value of the first image data of the first half plane of the liquid crystal panel 102 is adjusted upward by a different grayscale value, wherein the image data of the pixel corresponding to the first half plane of the liquid crystal panel 102 is further away from the integrated driving circuit 104. The larger the grayscale value is adjusted upwards. Therefore, after the traces of the source lines S1-S480 of the left half plane of the liquid crystal panel 102, the gray scale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 approaches the data voltage VR. As shown in FIG. 8, when the common voltage of the liquid crystal panel 102 is negative, the initial setting value of the register 1042 in the integrated driving circuit 104 is adjusted to correspond to the first image of the first half plane of the liquid crystal panel 102. The gray scale value of the data is adjusted downward by the different gray scale value, wherein the grayscale value of the image data corresponding to the pixel of the pixel which is larger than the first half plane of the liquid crystal panel 102 is further adjusted downward. Therefore, after the traces of the source lines S1-S480 of the left half plane of the liquid crystal panel 102, the gray scale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 approaches the data voltage VR. In addition, when the liquid crystal panel 102 is a vertical alignment technology (VA) panel, the first half plane corresponding to the first half plane of the liquid crystal panel 102 is adjusted through the initial setting value of the register 1042 in the integrated driving circuit 104. The direction of the grayscale value of an image data is opposite to that of the fifth, sixth, seventh, and eighth figures, and will not be further described herein. In step 406, the liquid crystal panel 102 displays the next screen according to the new image data, and then jumps back to step 402, and the integrated driving circuit 104 compares the liquid crystal surface again. The brightness of the first half plane of the board 102 and the brightness of the second half plane until the brightness of the first half plane of the liquid crystal panel 102 is the same as the brightness of the second half plane. Referring to Table 1, Table 1 is a diagram for adjusting the grayscale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 through the initial setting value of the register 1042 in the integrated driving circuit 104.

As shown in Table 1, when the initial set values TG2, TG1, and TG0 of the register 1042 are 0, 0, 0, the gray scale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 is The integrated driving circuit 104 originally sets the data voltage VR of the pixel output to the left half plane of the liquid crystal panel 102 to be lower by two steps. Therefore, by changing the initial setting values TG2, TG1, and TG0 of the register 1042, the grayscale value of the first image data corresponding to the first half plane of the liquid crystal panel 102 can be adjusted. However, the present invention is not limited to the correspondence between the initial setting values TG2, TG1, and TG0 of the register 1042 in Table 1 and the grayscale values of the first image data corresponding to the first half plane of the liquid crystal panel 102.

In summary, the method for driving a liquid crystal display according to the present invention is to compare the brightness of the first half plane of the liquid crystal panel with the brightness of the second half plane by using the integrated driving circuit when the liquid crystal panel displays the picture according to the image data. Then, when the brightness of the first half plane of the liquid crystal panel is not equal to the brightness of the second half plane of the liquid crystal panel, the initial setting value of the register in the integrated driving circuit is adjusted to adjust the brightness of the first half plane of the liquid crystal panel. Same brightness as the second half plane. As such, the present invention can solve the problem that the brightness of the first half plane of the liquid crystal panel is not equal to the brightness of the second half plane of the liquid crystal panel due to the difference in the trace impedance of the source lines.

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‧‧‧LCD display

102‧‧‧LCD panel

104‧‧‧Integrated drive circuit

1042‧‧‧ register

G1-G240‧‧‧ gate line

S1-S960‧‧‧ source line

V1, V2‧‧‧ voltage

VT, VT’‧‧‧ actual voltage

VR‧‧‧ data voltage

400 to 408 ‧ steps

Fig. 1 is a schematic view showing a liquid crystal display.

Fig. 2 is a schematic view showing the difference in brightness between the left half plane and the right half plane of the liquid crystal panel due to process factors.

Fig. 3 is a view showing that the actual voltage of the pixel in the left half plane of the liquid crystal panel is not equal to the data voltage of the pixel originally set to be outputted to the left half plane of the liquid crystal panel by the integrated type driving circuit.

4 is a flow chart showing a method of driving a liquid crystal display according to an embodiment of the present invention.

Figures 5 and 7 show that when the common voltage of the liquid crystal panel is positive, it will be The gray scale value of the first image data in the first half plane of the liquid crystal panel is adjusted upward to be higher than the data voltage of the pixel output from the integrated driving circuit originally set to the left half plane of the liquid crystal panel.

6 and 8 are diagrams for explaining that when the common voltage of the liquid crystal panel is negative, the gray scale value of the first image data corresponding to the first half plane of the liquid crystal panel is adjusted downward to be smaller than the integrated driving circuit. A schematic diagram of setting a low data voltage of a pixel output to the left half plane of the liquid crystal panel.

400 to 408. . . step

Claims (14)

A method for driving a liquid crystal display, the liquid crystal display comprising a liquid crystal panel and a driving circuit, the driving circuit comprising a temporary register, the method comprising: comparing a first half plane of the liquid crystal panel when displaying a picture according to an image data And the brightness of the second half plane; when the brightness of the first half plane is not equal to the brightness of the second half plane, adjusting the first image data corresponding to the first half plane of the image data to generate a a new image data; and the liquid crystal panel displays a next image according to the new image data; wherein the first half plane is a half plane of the liquid crystal panel that is far from the driving circuit, and the driving circuit is a source An integrated driving circuit of the driving circuit and a gate driving circuit. The method of claim 1, further comprising: comparing the brightness of the first half plane of the liquid crystal panel with the brightness of the second half plane when the next picture is displayed according to the new image data. The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is positive, the initial setting value of the register is adjusted. (initial code), the grayscale value of the first image data corresponding to the first half plane is adjusted upward by a same grayscale value. The method of claim 1, wherein adjusting the image data corresponds to the first The first image data of the half plane is such that when the common voltage of the liquid crystal panel is positive, the gray scale value corresponding to the first image data of the first half plane is adjusted upward by adjusting the initial setting value of the register. The gray scale value is different, wherein the grayscale value of the first image data corresponding to the pixel of the first half plane which is farther from the driving circuit is adjusted upwards. The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is negative, the initial setting value of the register is adjusted. The grayscale value of the first image data corresponding to the first half plane is adjusted downward by a same grayscale value. The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is negative, the initial setting value of the register is adjusted. And adjusting a grayscale value of the first image data corresponding to the first half plane downward by a different grayscale value, wherein the first image data of the pixel corresponding to the first half plane being farther from the driving circuit is downward The larger the adjusted grayscale value. The method of 4, 5 or 6, wherein the liquid crystal panel is a Twisted Nematic (TN) panel. The method of 4, 5 or 6, wherein the liquid crystal panel is a Super Twisted Nematic (STN) panel. The method of 4, 5 or 6, wherein the liquid crystal panel is a Thin Film Transistor Liquid Crystal Display (TFT-LCD). The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is positive, the initial setting value of the register is adjusted. The grayscale value of the first image data corresponding to the first half plane is adjusted downward by a same grayscale value. The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is positive, the initial setting value of the register is adjusted. And adjusting a grayscale value of the first image data corresponding to the first half plane downward by a different grayscale value, wherein the first image data of the pixel corresponding to the first half plane being farther from the driving circuit is downward The larger the adjusted grayscale value. The method of claim 1, wherein the first image data corresponding to the first half plane of the image data is adjusted, and when the common voltage of the liquid crystal panel is negative, the initial setting value of the register is adjusted. And adjusting the grayscale value of the first image data of the first half plane to an same grayscale value. The method of claim 1, wherein adjusting the image data corresponds to the first The first image data of the half plane is when the common voltage of the liquid crystal panel is negative, and the gray scale value corresponding to the first image data of the first half plane is adjusted upward by adjusting the initial setting value of the register. The gray scale value is different, wherein the grayscale value of the first image data corresponding to the pixel of the first half plane which is farther from the driving circuit is adjusted upwards. The method of claim 10, 11, 12 or 13, wherein the liquid crystal panel is a Vertical Alignment (VA) panel.