Liquid crystal display and its overdrive system

Abstract

This invention relates to an overdrive system suitable for liquid crystal displays. The overdrive system includes: a compressor for compressing an input signal to generate a compressed signal; a weighting device for generating a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal; and an overdrive driver that performs an overdrive operation based on the previously compressed signal and the weighted current signal. Embodiments of this invention can effectively avoid or reduce overdrive errors caused by image compression, thereby improving image quality and maintaining the image quality of still images.

Description

Technical Field

[0001] This invention relates to a display, and more particularly to an overdrive system suitable for liquid crystal displays. Background Technology

[0002] Liquid crystal displays (LCDs) are a type of flat panel display that regulates the amount of light passing through by rotating liquid crystal molecules. However, the rotation speed of these molecules is very low, typically lower than the image refresh rate. Therefore, images become blurry when scenes change rapidly. To compensate for this, an overdrive mechanism accelerates the rotation of the liquid crystals by delivering a higher voltage (instead of the required voltage) to each pixel.

[0003] However, in traditional overdrive systems, image compression can cause overdrive errors (such as flickering), thus significantly degrading image quality. In particular, still images are susceptible to overdrive errors due to image compression.

[0004] Therefore, there is an urgent need to propose a novel mechanism suitable for liquid crystal displays to overcome the shortcomings of traditional overdrive systems. Summary of the Invention

[0005] In view of the above, one of the objectives of this invention is to provide an overdrive system suitable for liquid crystal displays, which effectively avoids or reduces overdrive error response caused by image compression, thereby substantially improving image quality and maintaining the image quality of still images.

[0006] According to an embodiment of the present invention, an overdrive system includes a compressor, a weighting device, a determination device, and an overdrive driver. The compressor compresses the input signal to generate a compressed signal. The weighting device generates a weighted sum of the current compressed signal and the current input signal, thus obtaining a weighted current signal. The weighting operation performed by the weighting device is represented as follows: Current_weight = Cmp_Cur * (XCError_weight) + Cur * (1 - XCError_weight), where 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. The determination device determines whether an overdrive operation has been performed based on the previous compressed signal and the weighted current signal. The overdrive driver performs the overdrive operation based on the previous compressed signal and the weighted current signal.

[0007] According to the present invention, a liquid crystal display is also provided, 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 the pixels of the turned-on column of the display panel; and a timing controller for coordinating the scan driver and the data driver, the timing controller including an overdrive system comprising: a compressor for compressing an input signal to generate a compressed signal; a weighting device for generating a weighted sum of the current compressed signal and the current input signal to obtain a weighted current signal, wherein the weighting operation performed by the weighting device is represented as follows: Current_weight = Cmp_Cur * (XCError_weight) + Cur * (1 - XCError_weight), where 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; a determining device for determining whether an overdrive operation has been performed based on the previous compressed signal and the weighted current signal; and an overdrive driver for performing an overdrive operation based on the previous compressed signal and the weighted current signal. Attached Figure Description

[0008] Figure 1 A system block diagram of a liquid crystal display according to an embodiment of the present invention is shown.

[0009] Figure 2 This invention demonstrates that embodiments are applicable to ( ) Figure 1 System block diagram of the overdrive system of the timing controller.

[0010] Figure 3 The operation of the embodiment of the present invention is shown in ( Figure 1 A flowchart of the overdrive method for a timing controller.

[0011] Figure 4A show Figure 3 The detailed flowchart for step 24.

[0012] Figure 4B Example of a driven lookup table.

[0013] Figure 5 A schematic diagram illustrating a still image, where the previous input signal is the same as the current input signal.

[0014] Explanation of reference numerals in the attached figures:

[0015] 10: LCD monitor

[0016] 101: Display Panel

[0017] 102: Scan Driver

[0018] 103: Data Driver

[0019] 104: Timing Controller

[0020] 100: Overdrive system

[0021] 11: Compressor

[0022] 12: Storage device

[0023] 13: Weighting device

[0024] 14: Through driver

[0025] 141: Judgment device Detailed Implementation

[0026] Figure 1 This diagram shows a system block diagram of a liquid crystal display 10 according to an embodiment of the present invention. The liquid crystal display 10 of this embodiment may include a display panel 101, which includes a plurality of pixels arranged in a matrix. The liquid crystal display 10 of this embodiment may include a scan driver 102 (or a gate driver) for sequentially turning on at least one column of pixels in the display panel 101. The liquid crystal display 10 of this embodiment may include a data driver 103 (or a source driver) for providing image signals to the pixels in the turned-on column of the display panel 101. The liquid crystal display 10 of this embodiment may include a timing controller 104 for coordinating the scan driver 102 and the data driver 103.

[0027] Figure 2 This invention demonstrates that embodiments are applicable to ( ) Figure 1 System block diagram of the overdrive system 100 of the timing controller 104. Figure 3 The operation of the embodiment of the present invention is shown in ( Figure 1 The flowchart of the overdrive method 200 of the timing controller 104. Figure 2 The square and Figure 3 The steps can be implemented using hardware, software, or a combination thereof, such as by an image signal processor.

[0028] In this embodiment, the overdrive system 100 may include a (data) compressor 11 for compressing the (current) input signal (step 21) to generate a compressed signal, thereby reducing the data amount of the input signal, wherein the input signal represents the data displayed on (…). Figure 1 The image on the display panel 101 can be displayed. Image processing operations (such as smoothing) can be used to achieve spatial continuity, which is beneficial for subsequent overdrive operations.

[0029] The overdrive system 100 of this embodiment may include a storage device 12 (or a buffer) for temporarily storing the compressed signal as a previous (viewframe) compressed signal for subsequent overdrive operations (step 22).

[0030] The overdrive system 100 of this embodiment may include a weighting device 13 for generating a weighted sum of the current compressed signal (of the current view frame) and the current input signal (of the current view frame), thereby obtaining a weighted current signal (step 23). The weighting operation of the weighting device 13 can be represented as follows:

[0031] Current_weight=Cmp_Cur*(XCError_weight)+

[0032] Cur*(1-XCError_weight)

[0033] Where Current_weight represents the weighted current signal, Cmp_Cur represents the current compressed signal, Cur represents the current input signal, and XCError_weight represents the preset weight, the value of which is between 0 and 1.

[0034] In one embodiment, the greater the difference between the current compressed signal Cmp_Cur and the current input signal Cur, the larger the preset weight (close to 1). Therefore, 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 (close to 0). Therefore, the weighted current signal Current_weight is closer to the current input signal Cur.

[0035] The overdrive system 100 of this embodiment may include an overdrive 14, which performs an overdrive operation (step 24) based on a previously compressed signal (of storage device 12) and a weighted current signal (of weighting device 13).

[0036] In this embodiment, the overdrive 14 may include a determination device 141, which determines whether an overdrive operation has been performed based on the previous compression signal (of the previous view frame) and the weighted current signal (of the current view frame).

[0037] Figure 4A show Figure 3The detailed flowchart for step 24 is as follows: In step 241, the determining device 141 determines the difference between the previously compressed signal (of the previous view frame) and the weighted current signal (of the current view frame). Next, in step 242, the determining device 141 compares the difference with a preset threshold. If the difference is greater than the preset threshold, then (the determining device 141) initiates an overdrive operation to perform the overdrive operation (step 243); then, in step 244, the overdrive value is output to (…). Figure 1 Data driver 103. In this embodiment, the overdrive operation (step 243) can be implemented using a lookup table. Figure 4B An example of an overdrive lookup table is provided, which obtains the overdrive value based on the previously compressed signal (of the previous view frame) and the weighted current signal (of the current view frame). On the other hand, if the difference is not greater than a 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).

[0038] According to the above embodiments, overdrive errors (such as flickering) caused by image compression can be effectively avoided or reduced, thereby substantially improving image quality. In particular, still images are not subject to overdrive errors due to image compression, thus maintaining the image quality of still images.

[0039] Figure 5 A schematic diagram illustrating a still image, where the previous input signal is the same as the current input signal. For example... Figure 5 As illustrated, the (grayscale) value of the previously compressed signal is 64, while the value of the weighted current signal is 66. Since the difference between the previously compressed signal and the weighted current signal is not greater than a preset threshold (step 242), overdrive operation is not performed. Conversely, if the weighting operation of this embodiment is not performed, an overdrive value of 140 will be used for overdrive operation, which will cause flickering (i.e., an overdrive error response caused by image compression), thus substantially reducing image quality.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of patent protection of the present invention; all equivalent changes or modifications made without departing from the spirit disclosed in the invention should be included within the scope of protection of the present invention.

Claims

1. An overdrive system, characterized in that, The overdrive system includes: A compressor is used to compress an input signal to produce a compressed signal; A weighting device is used to generate a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal. The weighting operation performed by the weighting device is represented as follows: Current_weight = Cmp_Cur * (XCError_weight) + Cur * (1 - XCError_weight), where 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. The determining device determines whether a drive operation has been performed based on a previously compressed signal and the weighted current signal; and The overdrive driver performs the overdrive operation based on the previously compressed signal and the weighted current signal.

2. The overdrive system according to claim 1, characterized in that, The overdrive system further includes: A storage device that stores the compressed signal as the previously compressed signal.

3. The overdrive system according to claim 1, characterized in that, The greater the difference between the current compressed signal and the current input signal, the greater the preset weight; the smaller the difference between the current compressed signal and the current input signal, the smaller the preset weight.

4. The overdrive system according to claim 1, characterized in that, If the difference between the previously compressed signal and the weighted current signal is greater than a preset threshold, the judgment device initiates the overdrive operation and then outputs the overdrive value; otherwise, the judgment device does not initiate the overdrive operation and outputs the current input signal.

5. The overdrive system according to claim 4, characterized in that, The overdrive value is obtained by using an overdrive lookup table based on the previous compressed signal and the weighted current signal.

6. A liquid crystal display, characterized in that, The liquid crystal display includes: The display panel contains multiple pixels; A scan driver for sequentially activating at least one column of pixels on the display panel; A data driver for providing image signals to the pixels of the open column of the display panel; and A timing controller is used to coordinate the scan driver and the data driver, the timing controller including an overdrive system comprising: A compressor is used to compress an input signal to produce a compressed signal; A weighting device is used to generate a weighted sum of the current compressed signal and the current input signal, thereby obtaining a weighted current signal. The weighting operation performed by the weighting device is represented as follows: Current_weight = Cmp_Cur * (XCError_weight) + Cur * (1 - XCError_weight), where 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. The determining device determines whether a drive operation has been performed based on a previously compressed signal and the weighted current signal; and The overdrive driver performs the overdrive operation based on the previously compressed signal and the weighted current signal.

7. The liquid crystal display according to claim 6, characterized in that, The overdrive system further includes: A storage device that stores the compressed signal as the previously compressed signal.

8. The liquid crystal display according to claim 6, characterized in that, The greater the difference between the previous compressed signal and the current input signal, the greater the preset weight; the smaller the difference between the current compressed signal and the current input signal, the smaller the preset weight.

9. The liquid crystal display according to claim 6, characterized in that, If the difference between the previously compressed signal and the weighted current signal is greater than a preset threshold, the determination device initiates the overdrive operation and then outputs the overdrive value to the data driver; otherwise, the determination device does not initiate the overdrive operation and outputs the current input signal to the data driver.

10. The liquid crystal display according to claim 9, characterized in that, The overdrive value is obtained by using an overdrive lookup table based on the previous compressed signal and the weighted current signal.

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