CN116504192A

CN116504192A - Liquid crystal display and overdrive system thereof

Info

Publication number: CN116504192A
Application number: CN202210052288.1A
Authority: CN
Inventors: 吴东颖
Original assignee: Himax Technologies Ltd
Current assignee: Himax Technologies Ltd
Priority date: 2022-01-18
Filing date: 2022-01-18
Publication date: 2023-07-28

Abstract

The present invention relates to an overdrive system suitable for a liquid crystal display. The overdrive system includes: a compressor for compressing an input signal to generate a compressed signal; weighting means for generating a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal; and an overdrive unit for performing an overdrive operation based on the previous compressed signal and the weighted current signal. The embodiment of the invention can effectively avoid or reduce overdrive error response caused by compressing the image, thereby improving the image quality and maintaining the image quality of the still image.

Description

Liquid crystal display and overdrive system thereof

Technical Field

The present invention relates to a display, and more particularly, to an overdrive (overdrive) system suitable for a liquid crystal display.

Background

A liquid crystal display is a type of flat panel display that adjusts light passing therethrough by rotating liquid crystal molecules. However, the liquid crystal molecules rotate at a very low rate, typically lower than the update rate of the image. Therefore, when the scene changes rapidly, the image becomes blurred. To compensate for this, an overdrive (overdrive) mechanism accelerates the rotation of the driving liquid crystal by delivering a higher voltage (than the required voltage) to each pixel.

However, in the conventional overdrive system, the compressed image may cause an overdrive error reaction (such as flicker), thereby greatly reducing the image quality. In particular, still images may cause overdrive false reactions due to compressed images.

Therefore, a new mechanism for a liquid crystal display is needed to overcome the shortcomings of the conventional overdrive system.

Disclosure of Invention

In view of the foregoing, an objective of the embodiments of the present invention is to provide an overdrive system for a liquid crystal display, which effectively avoids or reduces overdrive error response caused by compressing images, thereby substantially improving image quality and maintaining image quality of still images.

According to an embodiment of the invention, an overdrive system comprises a compressor, a weighting device and an overdrive. The compressor compresses an input signal to generate a compressed signal. The weighting means generates a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal. The overdrive device performs overdrive operation according to the previous compressed signal and the weighted current signal.

Drawings

FIG. 1 is a system block diagram of a liquid crystal display according to an embodiment of the invention.

FIG. 2 is a system block diagram of an overdrive system suitable for use in the timing controller (FIG. 1) according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an overdrive method of the timing controller (FIG. 1) according to an embodiment of the present invention.

Fig. 4A shows a detailed flow chart of step 24 of fig. 3.

Fig. 4B illustrates an overdrive lookup table.

Fig. 5 illustrates a schematic diagram of a still image, in which a previous input signal is identical to a current input signal.

Reference numerals illustrate:

10: liquid crystal display device

101: display panel

102: scanning driver

103: data driver

104: time sequence controller

100: overdrive system

11: compression device

12: storage device

13: weighting device

14: overdrive device

141: judging device

Detailed Description

FIG. 1 is a system block diagram of a liquid crystal display 10 according to an embodiment of the invention. The liquid crystal display 10 of the present embodiment may include a display panel 101 including a plurality of pixels arranged in a matrix form. The lcd 10 of the present embodiment may include a scan driver 102 (or gate driver) for sequentially turning on at least one row of pixels of the display panel 101. The lcd 10 of the present embodiment may include a data driver 103 (or source driver) for providing image signals to the pixels of the turned-on columns in the display panel 101. The lcd 10 of the present embodiment may include a timing controller 104 for coordinating the scan driver 102 and the data driver 103.

Fig. 2 is a system block diagram of an overdrive (overdrive) system 100 suitable for the timing controller 104 (fig. 1) according to an embodiment of the present invention, and fig. 3 is a flowchart illustrating an overdrive method 200 operating on the timing controller 104 (fig. 1) according to an embodiment of the present invention. The blocks of fig. 2 and the steps of fig. 3 may be implemented using hardware, software, or a combination thereof, for example, as implemented in an image signal processor.

In this embodiment, the overdrive system 100 may include a (data) compressor 11 for compressing a (current) input signal (step 21) to generate a compressed signal, thereby reducing the data size of the input signal, wherein the input signal represents an image displayed on the display panel 101 (fig. 1). Image processing operations (e.g., smoothing) may be used to achieve spatial continuity, facilitating subsequent overdrive operations.

The overdrive system 100 of the present embodiment may include a storage device 12 (or buffer) for temporarily storing the compressed signal as a previous (frame) compressed signal for a subsequent overdrive operation (step 22).

The overdrive system 100 of the present embodiment may comprise weighting means 13 for generating a weighted sum of the current compressed signal (of the current frame) and the current input signal (of the current frame) and thus obtaining a weighted current signal (step 23). The weighting operation of the weighting means 13 can be expressed as follows:

Current_weight＝Cmp_Cur*(XCError_weight)+

Cur*(1-XCError_weight)

wherein current_weight represents a weighted Current signal, cmp_cur represents a Current compressed signal, cur represents a Current input signal, and xcerror_weight represents a preset weight, the value of which is between 0 and 1.

In one embodiment, the larger the difference between the current compression signal cmp_cur and the current input signal Cur, the larger the preset weight (close to 1). Thus, the weighted Current signal current_weight is closer to the Current compressed signal cmp_cur. Conversely, the smaller the difference between the current compressed signal cmp_cur and the current input signal Cur, the smaller the preset weight (near 0). Thus, the closer the weighted Current signal current_weight is to the Current input signal Cur.

The overdrive system 100 of the present embodiment may include an overdrive 14 that performs an overdrive operation based on the previous compressed signal (of the storage device 12) and the weighted current signal (of the weighting device 13) (step 24).

In this embodiment, the overdrive 14 may include a judging device 141 for judging whether to perform the overdrive operation based on the previous compressed signal (of the previous frame) and the weighted current signal (of the current frame).

Fig. 4A shows a detailed flow chart of step 24 of fig. 3. In step 241, the decision means 141 decides the difference between the previous compressed signal (of the previous frame) and the weighted current signal (of the current frame). Next, in step 242, the determining device 141 compares the difference value with a predetermined threshold. If the difference is greater than the preset threshold, the overdrive operation is started (decision means 141) to perform the overdrive operation (step 243); next, in step 244, the overdrive value is output to the data driver 103 (fig. 1). In this embodiment, the overdrive operation (step 243) may be implemented using a lookup table. Fig. 4B illustrates an overdrive look-up table, from which overdrive values are derived from a previous compressed signal (of a previous frame) and a weighted current signal (of a current frame). On the other hand, if the difference is not greater than the preset threshold, the overdrive operation is omitted (or not started) (step 243), and the current input signal is output to the data driver 103 (step 245).

According to the above embodiments, overdrive error response (e.g., flicker) caused by compressing an image can be effectively avoided or reduced, thereby substantially improving the image quality. In particular, the still image does not cause an overdrive error reaction due to the compressed image, so that the image quality of the still image can be maintained.

Fig. 5 illustrates a schematic diagram of a still image, in which a previous input signal is identical to a current input signal. As illustrated in fig. 5, the (gray) value of the previous compressed signal is 64, whereas the value of the weighted current signal is 66. Since the difference between the previous compressed signal and the weighted current signal is not greater than the predetermined threshold (step 242), no overdrive operation is performed. In contrast, if the weighting operation of the present embodiment is not performed, the overdrive operation is performed using the overdrive value of 140, which causes flicker (i.e., overdrive error response due to compressed image), thereby substantially reducing the image quality.

The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention; all such equivalent changes and modifications that do not depart from the spirit of the invention are intended to be included within the scope of the present invention.

Claims

1. An overdrive system, said overdrive system comprising:

a compressor for compressing an input signal to generate a compressed signal;

weighting means for generating a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal; a kind of electronic device with high-pressure air-conditioning system

And an overdrive unit for performing overdrive operation based on the previous compressed signal and the weighted current signal.

2. The overdrive system according to claim 1, wherein the overdrive system further comprises:

a storage device that stores the compressed signal as the previously compressed signal.

3. The overdrive system according to claim 1, wherein the weighting operation performed by the weighting means is represented as follows:

Current_weight＝Cmp_Cur*(XCError_weight)+

Cur*(1-XCError_weight)

wherein current_weight represents the weighted Current signal, cmp_cur represents the Current compressed signal, cur represents the Current input signal, and xcerror_weight represents a preset weight.

4. An overdrive system according to claim 3, characterized in that the larger the difference between the current compressed signal and the current input signal, the larger the preset weight; the smaller the difference between the current compressed signal and the current input signal is, the smaller the preset weight is.

5. The overdrive system according to claim 1, wherein said overdrive includes a judging means for judging whether to perform said overdrive operation based on said previous compression signal and said weighted current signal.

6. The overdrive system according to claim 5, wherein said judging means starts said overdrive operation and then outputs an overdrive value if a difference between said previous compressed signal and said weighted current signal is greater than a preset threshold value; otherwise, the judging device does not start the overdrive operation and outputs the current input signal.

7. The overdrive system according to claim 6, wherein said overdrive value is derived via an overdrive look-up table based on said previous compressed signal and said weighted current signal.

8. A liquid crystal display, the liquid crystal display comprising:

a display panel including a plurality of pixels;

a scan driver for sequentially turning on at least one column of pixels of the display panel;

a data driver for providing image signals to pixels of an on-column of the display panel; a kind of electronic device with high-pressure air-conditioning system

A timing controller for coordinating the scan driver and the data driver, the timing controller comprising an overdrive system comprising:

a compressor for compressing an input signal to generate a compressed signal;

9. The liquid crystal display of claim 8, wherein the overdrive system further comprises:

10. The liquid crystal display of claim 8, wherein the weighting operation performed by the weighting means is represented as follows:

Current_weight＝Cmp_Cur*(XCError_weight)+

Cur*(1-XCError_weight)

11. The lcd of claim 10, wherein the larger the difference between the pre-compression signal and the current input signal, the larger the preset weight; the smaller the difference between the current compressed signal and the current input signal is, the smaller the preset weight is.

12. The liquid crystal display of claim 8, wherein the overdrive device comprises a judging means for judging whether to perform the overdrive operation based on the previous compression signal and the weighted current signal.

13. The liquid crystal display of claim 12, wherein if the difference between the previous compressed signal and the weighted current signal is greater than a preset threshold, the determining means starts the overdrive operation and then outputs an overdrive value to the data driver; otherwise, the judging device does not start the overdrive operation and outputs the current input signal to the data driver.

14. The lcd of claim 13, wherein the overdrive value is obtained via an overdrive lookup table based on the previous compressed signal and the weighted current signal.