TWI383373B - Liquid crystal display device - Google Patents

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device.

The liquid crystal display device has the characteristics of small size, low power consumption and low radiation, and is widely used in the fields of monitors, LCD TVs, mobile phones, and notebook computers, and has gradually become the mainstream of the market. However, the liquid crystal itself is a viscous coefficient substance, and the reaction speed of the liquid crystal display device cannot compete with the CRT display. When the screen is quickly switched, the reaction speed of the liquid crystal is too slow, resulting in an image that is too late to be converted to display a grayscale image, that is, a residual image phenomenon.

Please refer to FIG. 1 , which is a schematic diagram of a dynamic image response curve (MPRC) of a prior art liquid crystal display panel. The vertical axis of the dynamic image response graph represents the brightness value after the regularization. The horizontal axis represents the relative position between the pixels. For example, the symbol 600 is the pixel on the left side of the liquid crystal display panel, the reference numeral 1000 is the pixel on the right side of the liquid crystal display panel, and the indicator 800 is the pixel in the middle of the liquid crystal display panel. The dynamic image response curve is a simulated curve drawn by reference light generation time, liquid crystal reaction time, and human visual response time. The dynamic image response curve represents an afterimage phenomenon caused by the moving object moving from the horizontal axis 600 to the horizontal axis 1000 in the background brightness environment. The pixel on the left shows the background, and the pixel on the right shows the object after the movement, whereby it can be found that there is a sloped area between the pixel 700 and the pixel 900. The oblique curve area displays a gray level which is lighter than the object due to the brightness value being between the background and the object, which indicates that there is a blurred area between the background and the object, that is, an afterimage phenomenon. Therefore, due to the slow reaction speed of the liquid crystal, the middle portion still shows a light gray scale, and the brightness is between Between 0~1.

Please refer to FIG. 2, which is a block diagram of a prior art liquid crystal display device. The liquid crystal display device 1 includes a microprocessor (MCU) 11, an overdrive circuit 12, and a liquid crystal display panel 13. The microprocessor 11 is connected to the overdrive circuit 12, and the overdrive circuit 12 is connected to the liquid crystal display panel 13.

The overdrive circuit 12 includes a Look Up Tables (LUTs), each of which stores a complex original gray scale and a complex corrected gray scale corresponding to the original gray scale. The complex lookup table is stored in a hardware medium. The microprocessor 11 is configured to receive a gray scale display signal and generate an original gray scale. The overdrive circuit 12 receives the original gray scale, finds a corrected gray scale corresponding to the original gray scale in the lookup table, and outputs the corrected gray scale to the liquid crystal display panel 13. The liquid crystal display panel 13 displays a corresponding image based on the received grayscale correction. For example, the microprocessor 11 receives a grayscale display signal of a luminance value 192 that produces a corresponding original grayscale. The original gray scale is input to the overdrive circuit, and a corrected gray scale signal of a luminance value 202 is output. Therefore, the reaction speed of the liquid crystal is enhanced by increasing the voltage to enhance the display effect.

However, the complex lookup table of the overdrive circuit 12 stores a complex original gray scale and a complex corrected gray scale corresponding to the original gray scale in each lookup table, and the complex corrected gray scales are all preset values are not adjustable, The factors such as the reference light generation time and the human visual response time make the output image of the liquid crystal display panel 13 fail to achieve the best effect. In addition, the complex lookup table is stored in a hardware medium, which also increases circuit design complexity and increases cost.

In view of this, it is necessary to provide a liquid crystal display device with more accurate display, simple circuit design, and lower cost.

A liquid crystal display device includes an image signal output terminal, a frame buffer, a microprocessor and a liquid crystal display panel. The image signal output end is used for sequentially outputting a plurality of frame image signals. The frame buffer is configured to sequentially receive the plurality of frame image signals transmitted by the image signal output end, and sequentially store the plurality of frame image signals for one frame time before outputting. The microprocessor is configured to receive an image signal output by the frame buffer and an image signal transmitted by the image signal output end, and obtain a difference signal of the adjacent two frame image signals, and the difference signal is Multiplying a predetermined coefficient produces an output signal that is added to the image signal transmitted by the image signal output to generate a display signal. The liquid crystal display panel is configured to receive display signals and implement image display.

A liquid crystal display device includes an image signal output terminal, a first frame buffer, a second frame buffer, a microprocessor and a liquid crystal display panel. The image signal output end is used for sequentially outputting a plurality of frame image signals. The second frame buffer is configured to sequentially receive the plurality of frame image signals transmitted by the image signal output end, and sequentially store the plurality of frame image signals for one frame time before outputting. The first frame buffer is configured to sequentially receive the plurality of frame image signals transmitted by the second frame buffer, and sequentially store the plurality of frame image signals for one frame time before outputting. The microprocessor is configured to receive an image signal transmitted by the second frame buffer and an image signal transmitted by the first frame buffer, and obtain a difference signal of the adjacent two frame image signals, and the difference is The signal is multiplied by a predetermined coefficient to generate an output signal, and the output signal is added to the image signal transmitted by the second frame buffer to generate a display signal. The liquid crystal display panel is used for connection Receive the display signal and realize the image display.

Compared with the prior art, the liquid crystal display device receives the current adjacent frame and the previous frame image signal by the microprocessor, and obtains a difference signal of the adjacent two frame image signals, and the difference signal is Multiplying a predetermined coefficient produces an output signal that is added to the current frame image signal of the external input and produces a display signal to make the image display more accurate. In addition, the elimination of a hard medium makes the circuit design simple and low cost.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of a module of a first embodiment of a liquid crystal display device of the present invention. The liquid crystal display device 3 includes an image signal output terminal (not shown), a first frame buffer (Frame Buffer) 32, a second frame buffer 31, a subtractor 33, a multiplier 34, and an adder. 35 and a liquid crystal display panel 36. The subtractor 33, the multiplier 34 and the adder 35 constitute a microprocessor (not shown).

The image signal output end is used to sequentially output the first, second, third, ... (n≧1) image signal image signals. The second frame buffer 31 is configured to sequentially receive the first, second, third, ... n frame image signals transmitted by the image signal output end, and sequentially store the plurality of frame image signals for one frame time. Thereafter, it is sequentially transmitted to the first frame buffer 32. The first frame buffer 32 is configured to sequentially receive the first, second, third, ... n frame image signals transmitted by the second frame buffer 31, and sequentially perform the frame time signal on the plurality of frame image signals. After the temporary storage, it is sequentially transmitted to the subtractor 33. The subtracter 33 is configured to receive an image signal of the nth frame transmitted by the second frame buffer 31 and an image signal of the n-1th frame transmitted by the first frame buffer 32, and generate a difference between the two. Value signal. The multiplier 34 Receiving the difference signal and multiplying the difference signal by a predetermined coefficient to generate an output signal. The adder 35 receives the output signal of the multiplier 34 and the image signal of the nth frame output by the second frame buffer 31, performs an addition operation on the two signals, and generates a display signal. The liquid crystal display panel 36 is configured to receive display signals and implement image display.

It is assumed that the human eye can see each frame image of the liquid crystal display panel 36, En indicates that the human eye sees the image signal displayed in the nth frame of the liquid crystal display panel 36, and Fn represents the image of the liquid crystal display panel 36 in the nth frame. The signal, Fn-1, represents the image signal of the liquid crystal display panel 36 in the n-1th frame. When the liquid crystal display panel 36 displays the image of the nth frame, the human eye does not perceive the image of the nth frame, but feels the weight average of the images of the nth frame and the n-1th frame. The relationship between En and Fn and Fn-1 is as follows: En=aFn+bFn-1, where 0≦a≦1, 0≦b≦1, and a+b=1.

The equation indicates that the image seen by the human eye is the weight average of the image of the liquid crystal display panel 36 in the nth frame and the image of the liquid crystal display panel 36 in the n-1th frame.

According to the above reasoning, if the human eye is not affected by the image displayed in the previous frame, the image Fn displayed on the liquid crystal display panel 36 needs to be changed to Fn' so that the image perceived by the human eye is Fn. That is: En=aFn'+bFn-1, and En=Fn.

Finished, Fn' = Fn + (Fn - Fn-1) b / a.

It can be seen that if the image of the nth frame is not affected by the image of the previous frame n-1, the image Fn' displayed in the nth frame of the liquid crystal display panel 36 is required to be the original image. The image displayed in the nth frame plus the sum of the difference between the nth frame image and the n-1th frame image and the coefficient value. The preferred range of the coefficient b/a is between 0.5 and 19. For example, a is 0.6, b is 0.4, and b/a is 2/3, and Fn'=Fn+2(Fn-Fn-1)/3 is obtained.

The two frame buffers 31 and 32 respectively transmit the nth frame and the n-1th frame image signal to the subtractor 33 to obtain a difference Fn-Fn-1. The multiplier 34 receives the difference and multiplies the result by the ratio b/a, and the result is transmitted to the adder 35. At this time, the adder 35 also receives the nth frame image signal of the second frame buffer 31. The received two signals are added and transmitted to the liquid crystal display panel 36 to realize screen display.

Compared with the prior art, the liquid crystal display device 3 receives the n-1th and nth frame image signals of the two adjacent frames by the microprocessor, and obtains the difference signal of the adjacent two frames of image signals, and The difference signal is multiplied by a predetermined coefficient b/a to generate an output signal, and the output signal is added to the nth frame image signal input by the image signal output terminal to generate a display signal, so that the image display is further displayed. accurate. In addition, the elimination of a hard medium makes the circuit design simple and low cost.

Please refer to FIG. 4, which is a schematic diagram of a second embodiment of a liquid crystal display device of the present invention. The liquid crystal display device 4 is substantially the same as the liquid crystal display device 3 of the first embodiment, and the main difference is that the liquid crystal display device 4 includes an on screen display (OSD) 47, and the screen display control system 47 Connected to the multiplier 44 for adjusting the coefficient b/a. The user can adjust the screen display control system 47 under certain screens to make the liquid crystal display panel 46 output a picture to achieve the best effect.

The liquid crystal display device of the present invention may also have various other modifications, such as: the liquid crystal display device includes only one frame buffer. The frame buffer is used to sequentially connect Receiving the first, second, third, and nth (n≧1) image signals transmitted by the image signal output end, and sequentially storing the plurality of frame image signals for one frame time, and then sequentially transmitting the image signals to the image signal Subtractor. The subtracter receives the image signal of the nth frame transmitted by the image signal output end and the image signal of the n-1th frame of the frame buffer and generates a difference signal between the two.

In summary, the present invention has indeed met the requirements of the invention patent, 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 equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

Liquid crystal display device ‧‧3,4

Second frame buffer ‧‧31

First frame buffer ‧‧‧32

Subtractor ‧‧33

Multiplier ‧‧·34,44

Adder ‧‧35

LCD panel ‧‧‧36,46

Screen display control system ‧‧47

1 is a schematic diagram of a dynamic image response curve of a prior art liquid crystal display panel.

2 is a block diagram of a prior art liquid crystal display device.

3 is a schematic block diagram of a first embodiment of a liquid crystal display device of the present invention.

4 is a schematic block diagram of a second embodiment of a liquid crystal display device of the present invention.

Liquid crystal display device ‧‧3

Second frame buffer ‧‧31

First frame buffer ‧‧‧32

Subtractor ‧‧33

Multiplier ‧‧34

Adder ‧‧35

LCD panel ‧‧36

Claims (12)

A liquid crystal display device comprising: an image signal output end for sequentially outputting a plurality of frame image signals; a frame buffer for sequentially receiving a plurality of frame image signals transmitted by the image signal output end, and sequentially The plurality of frame image signals are temporarily stored for one frame time and then output; a microprocessor is configured to receive the image signal output by the frame buffer and the image signal transmitted by the image signal output end, and obtain a difference signal of the adjacent two frames of image signals, and multiplying the difference signal by a predetermined coefficient to generate an output signal, and the output signal is added to the image signal transmitted by the image signal output end to generate a Display signal; and a liquid crystal display panel for receiving display signals and realizing image display. The liquid crystal display device of claim 1, wherein the microprocessor further comprises a subtractor for receiving a current frame image signal transmitted by the image signal output end and the frame buffer output. The image signal of one frame before the current frame image signal and the difference signal of the two are generated. The liquid crystal display device of claim 2, wherein the microprocessor further comprises a multiplier, the multiplier receiving the difference signal and multiplying by a predetermined coefficient to generate an output signal, the predetermined coefficient The range is between 0.5 and 19. The liquid crystal display device of claim 3, further comprising a screen display control system, wherein the screen display control system is coupled to the multiplier to control the magnitude of the predetermined coefficient. The liquid crystal display device of claim 3, wherein the microprocessor further comprises an adder, wherein the adder receives the output signal of the multiplier and the current transmission of the image signal output end The frame image signal performs an addition operation on the two signals and generates a display signal. The liquid crystal display device of claim 3, wherein the predetermined coefficient is 2/3. A liquid crystal display device includes: an image signal output end for sequentially outputting a plurality of frame image signals; and a second frame buffer for sequentially receiving a plurality of frame image signals transmitted by the image signal output end, And sequentially outputting the plurality of frame image signals for one frame time and then outputting; a first frame buffer for sequentially receiving the plurality of frame image signals transmitted by the second frame buffer, and sequentially the plurality of frames The frame image signal is temporarily stored for one frame time and then output; a microprocessor is configured to receive the image signal transmitted by the second frame buffer and the image signal transmitted by the first frame buffer, to obtain the image signal a difference signal of the adjacent two frames of image signals, and multiplying the difference signal by a predetermined coefficient to generate an output signal, the output signal is added to the image signal transmitted by the second frame buffer to generate a display a signal; and a liquid crystal display panel for receiving display signals and realizing image display. The liquid crystal display device of claim 7, wherein the microprocessor further comprises a subtractor, configured to receive a current frame image signal transmitted by the second frame buffer and the first frame buffer Outputs the image signal of the previous frame of the current frame image signal and produces the difference between the two Signal. The liquid crystal display device of claim 8, wherein the microprocessor further comprises a multiplier, the multiplier receiving the difference signal and multiplying by a predetermined coefficient to generate an output signal, the predetermined coefficient The range is between 0.5 and 19. The liquid crystal display device of claim 9, further comprising a screen display control system, the screen display control system being coupled to the multiplier to control the magnitude of the predetermined coefficient. The liquid crystal display device of claim 9 or claim 10, wherein the microprocessor further comprises an adder, the adder receiving the output signal of the multiplier and the second frame buffer transmission diagram Like the signal, the addition operation is performed on the two signals and a display signal is generated. The liquid crystal display device of claim 9, wherein the predetermined coefficient is 2/3.