CN1936653A - Liquid crystal display and its driving method - Google Patents

Abstract

A driving method of a liquid crystal display includes the steps of: first, the frame data displayed by the LCD in each frame time is recorded. Then, the picture data displayed in each frame time is compared with the picture data displayed in the previous frame time. And then, adjusting the gray value difference between the maximum brightness and the minimum brightness displayed by the pixels of the liquid crystal display in the frame time according to the comparison result. The driving method of the liquid crystal display can improve the display quality of the liquid crystal display.

Description

Liquid crystal display and its driving method

technical field

The present invention relates to a display device and a driving method thereof, in particular to a liquid crystal display (Liquid Crystal Display, LCD) and a driving method thereof.

Background technique

Due to the advent of the information society, the demand for displays as an information transmission medium is also increasing day by day, so the industry is fully committed to the development of related displays. Among them, the cathode ray tube (Cathode Ray Tube, CRT) display has been monopolizing the display market for many years because of its good display quality and technological maturity. However, in recent years, high-tech products have gradually become thinner and smaller. Therefore, liquid crystal displays with superior characteristics such as high image quality, good space utilization efficiency, low power consumption, and no radiation have gradually replaced cathode ray tube displays and become the current display. the mainstream of the market.

Both of the above two displays have their advantages and disadvantages. In terms of display quality, the cathode ray tube display uses electron beams and is driven by an impulse type to emit light, that is to say, within one frame time, the cathode ray tube display After the pixel is excited by a short time pulse to emit light, it returns to the dark state immediately, so the brightness of the pixel will change with time, so it can have better display quality when displaying dynamic images. However, when a static picture is displayed with pulsed light, the problem of picture flickering is likely to occur, so that the viewer's eyes are prone to feel tired and uncomfortable after watching the static picture for a long time.

In liquid crystal displays, at present, most of them use a hold type to drive light emission. In other words, within each frame time of the liquid crystal display, the brightness of the backlight source maintains a constant value, and the brightness of the pixel is determined only by the rotation of the liquid crystal. In this way, the brightness of the pixel will maintain a constant value after being driven. Therefore, when the liquid crystal display displays a static picture, the problem of picture flickering does not occur, which can make the viewer's eyes more comfortable when watching the static picture. However, if the backlight of the liquid crystal display is used to display dynamic pictures, the problem of picture blurring (blurring) will occur due to the characteristics of human vision.

In order to make the liquid crystal display have better display quality when displaying dynamic pictures, the known technology is to use a type of pulsed backlight source, that is, the backlight source is switched periodically, so that the liquid crystal display can be connected to the cathode when displaying dynamic pictures. Ray tube monitors have the same display quality. Generally speaking, the luminous amplitude of this type of pulsed backlight maintains a constant value, that is, the brightness difference between the maximum brightness and the minimum brightness of the backlight is fixed. However, this approach will cause the liquid crystal display to have the shortcomings of the cathode ray tube display when displaying static images, thus losing its original advantages.

Contents of the invention

Therefore, the purpose of the present invention is to provide a liquid crystal display and its driving method, so that the liquid crystal display has better display quality when displaying dynamic images, and does not have flickering phenomenon when displaying static images.

Based on the above and other objectives, the present invention proposes a driving method of a liquid crystal display, which includes the following steps: first, record the picture data displayed by the liquid crystal display in each frame time. Next, compare the frame data displayed in each frame time with the frame data displayed in the previous frame time. Afterwards, the gray scale difference between the maximum brightness and the minimum brightness displayed by the pixels of the liquid crystal display is adjusted within the frame time according to the comparison result. Wherein, the method of comparing the frame data is, for example, comparing whether there is a similar pattern in the frame data displayed in each frame time and the frame data displayed in the previous frame time. When there is a similar pattern, calculate the moving amount of the pattern to judge whether the liquid crystal display is displaying a dynamic picture or a static picture, and adjust the luminous amplitude of the backlight according to the judgment result, that is, adjust the maximum brightness and the minimum brightness of the backlight Brightness is poor.

In the above driving method of the liquid crystal display, the liquid crystal display has, for example, a backlight source, and the method for making the liquid crystal display have better display quality within this frame time is, for example, to first determine whether the movement amount is greater than a reference value. When the movement amount is greater than the reference value, we can judge that the LCD is displaying a dynamic picture, then adjust the luminous amplitude of the backlight within this frame time to A1; when the movement amount is less than the reference value, we can judge that the LCD display is in To display a static picture, adjust the luminous amplitude of the backlight within the frame time to A2, where A1>A2. In addition, when the movement amount is equal to the reference value, the lighting amplitude of the backlight within the frame time can be between A1 and A2.

In the above-mentioned driving method of the liquid crystal display, the backlight includes, for example, a plurality of cold cathode fluorescent lamps, and the method of adjusting the luminous amplitude of the backlight, for example, is to adjust the magnitude of the current passing through the cold cathode fluorescent lamps.

In the driving method of the above-mentioned liquid crystal display, the backlight source also includes an inverter circuit, and this inverter circuit is suitable for applying a voltage waveform to the cold cathode fluorescent lamp to adjust the luminous amplitude of the backlight source, and the voltage waveform is divided into multiple A positive half cycle and a plurality of negative half cycles, and the method of adjusting the luminous amplitude of the backlight includes adjusting the voltage waveform of the inverter circuit. In one embodiment, the method for adjusting the voltage waveform includes keeping the maximum voltage amplitude value and the minimum voltage amplitude value of the voltage waveform unchanged, and generating a plurality of negative voltage pulses in the positive half cycle of the voltage waveform, and generating a plurality of negative voltage pulses in the negative half cycle of the voltage waveform. Multiple positive voltage pulses. In another embodiment, the method for adjusting the voltage waveform includes keeping the maximum voltage amplitude value and the minimum voltage amplitude value of the voltage waveform unchanged, and generating a plurality of negative pulses in the positive half cycle of the voltage waveform, and generating a plurality of negative pulses in the negative half cycle of the voltage waveform. Generates multiple positive going pulses.

In the driving method of the above-mentioned liquid crystal display, the backlight source includes, for example, a plurality of light emitting diode arrays, and the method of adjusting the luminous amplitude of the backlight source is, for example, adjusting the magnitude of the current passing through these light emitting diode arrays or adjusting the light emitting diodes of these light emitting diode arrays. number of glows.

In the driving method of the above-mentioned liquid crystal display, the liquid crystal display has, for example, a scanning backlight source, which includes a plurality of sub-light sources corresponding to different sections of the liquid crystal display, and these sub-light sources are switched periodically, and within the frame time A method for making the liquid crystal display have a better display quality is, for example, first to determine whether the liquid crystal display displays a dynamic pattern or a static pattern in each block. When the liquid crystal display is displaying a dynamic pattern, the light-emitting amplitude of the sub-light source of the scanning backlight corresponding to the block where the dynamic pattern is located is adjusted to A1 within the frame time. When the liquid crystal display is displaying a static pattern, the luminous amplitude of the sub-light sources of the scanning backlight corresponding to the block where the static pattern is located is adjusted to A2 within the frame time, wherein A1>A2.

In the above-mentioned driving method of the liquid crystal display, each sub-light source is, for example, a cold cathode fluorescent lamp, and the method for adjusting the luminous amplitude of the scanning backlight includes adjusting the magnitude of the current passing through the cold cathode fluorescent lamps.

In the driving method of the above-mentioned liquid crystal display, the backlight source further includes an inverter circuit, and the inverter circuit is suitable for applying a voltage waveform to the cold cathode fluorescent lamp to adjust the luminous amplitude of the scanning backlight source, and the voltage waveform is divided into multiple One positive half cycle and multiple negative half cycles, and the method of adjusting the light emission amplitude of the scanning backlight includes adjusting the voltage waveform of the inverter circuit. In one embodiment, the method for adjusting the voltage waveform of the inverter circuit includes keeping the maximum voltage amplitude value and the minimum voltage amplitude value of the voltage waveform unchanged, and generating a plurality of negative voltage pulses in the positive half cycle of the voltage waveform, and then The negative half cycle of the voltage waveform produces multiple positive voltage pulses. In another embodiment, the method for adjusting the voltage waveform includes keeping the maximum voltage amplitude value and the minimum voltage amplitude value of the voltage waveform unchanged, and generating a plurality of negative pulses in the positive half cycle of the voltage waveform, and generating a plurality of negative pulses in the negative half cycle of the voltage waveform. Generates multiple positive going pulses.

In the above-mentioned driving method of a liquid crystal display, each sub-light source is, for example, an array of light emitting diodes, and the method for adjusting the luminous amplitude of the scanning backlight includes adjusting the magnitude of the current passed into these arrays of LEDs or adjusting the current of these arrays of LEDs. The number of LEDs to emit light.

In the above-mentioned driving method of the liquid crystal display, the method for making the liquid crystal display have better display quality within the frame time is, for example, inserting a black frame into the frame data displayed within the frame time. Wherein, the so-called inserting a black picture refers to inputting a low-grayscale picture data during a certain period within a frame time.

In the above-mentioned driving method of the liquid crystal display, the method for making the liquid crystal display have better display quality within the frame time is, for example, first to determine whether the liquid crystal display displays dynamic patterns or static patterns. When the liquid crystal display is displaying a dynamic pattern, a first black frame is inserted within this frame time, and when the liquid crystal display is displaying a static pattern, a second black frame is inserted within this frame time, wherein the second The grayscale value of the black picture is higher than the grayscale value of the first black picture, that is, the brightness of the second black picture is higher than the brightness of the first black picture.

In the above-mentioned driving method of the liquid crystal display, when inserting the first black frame or the second black frame, for example, the first black frame or the second black frame is inserted into the entire frame data.

In the above driving method of the liquid crystal display, when inserting the first black frame or the second black frame, for example, the first black frame or the second black frame is inserted into the partial frame data displaying the pattern.

In the above-mentioned driving method of the liquid crystal display, before inserting the first black frame or the second black frame, for example, it further includes increasing the grayscale value of the frame data displayed within this frame time.

In the above-mentioned driving method of the liquid crystal display, the liquid crystal display has a backlight source, and before inserting the first black frame or the second black frame, for example, it further includes increasing the luminance of the backlight source within the frame time.

The present invention also provides a liquid crystal display, which has a display panel and a backlight that can be switched on and off periodically. Wherein, the brightness difference between the maximum brightness and the minimum brightness of the backlight source in each cycle can be adjusted according to the characteristics of the display screen.

In the above-mentioned liquid crystal display, the picture characteristic refers to, for example, a dynamic picture or a static picture.

In the above-mentioned liquid crystal display, the screen characteristics refer to, for example, a complex screen or a monotonous screen.

The invention can make the liquid crystal display change the luminous amplitude of the backlight source within the frame time of displaying dynamic pictures, so as to achieve the effect similar to the pulsed luminous display of a cathode ray tube display, and make the display of static pictures within the frame time. The brightness of the backlight is fixed. Therefore, whether the liquid crystal display is displaying a dynamic image or a static image, it can have better display quality.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 shows a flow chart of the steps of a method for driving a liquid crystal display in a preferred embodiment of the present invention.

FIG. 2A shows the image data displayed by the liquid crystal display in the M-1th frame time.

FIG. 2B shows the image data displayed by the liquid crystal display in the Mth frame time.

FIG. 3 is a graph showing the relationship between the luminance of the backlight source of the liquid crystal display and time.

FIG. 4 is a graph showing the relationship between the luminance of the backlight source of the liquid crystal display and time.

5A to 5F are graphs showing the comparison of the light emission amplitude of the backlight source of the liquid crystal display and the voltage waveform of the inverter circuit.

Description of reference symbols

50, 60: screen data

100, 200, 300: curve

E: pattern

L1, L2, L3, L4: Lines

S110: record the picture data displayed by the liquid crystal display in each frame time

S120: Compare the picture data displayed in each frame time with the picture data displayed in the previous frame time

S130: adjust the gray value difference between the maximum brightness and the minimum brightness displayed by the pixels of the liquid crystal display within the frame time according to the comparison result

Detailed ways

The present invention first judges that the picture to be displayed by the liquid crystal display is a static or dynamic picture, and then selects a more appropriate driving method to drive the backlight according to the judgment result or decides whether to insert a black picture into the picture to be displayed according to the judgment result, so as to improve the performance of the liquid crystal display. The display quality of the monitor. The following examples will be given to illustrate the present invention, but they are not intended to limit the present invention. Those skilled in the art may slightly modify the following examples according to the spirit of the present invention, but they still belong to the scope of the present invention.

Fig. 1 has shown the flow chart of the step of the driving method of liquid crystal display of a preferred embodiment of the present invention, and Fig. 2A has shown the picture data that liquid crystal display shows in M-1th frame time, and Fig. 2B shows The picture data displayed by the liquid crystal display in the Mth frame time is shown. In addition, FIG. 3 shows a graph showing the relationship between the luminous brightness of the backlight source of the liquid crystal display and time. Please refer to FIG. 1, FIG. 2A, FIG. 2B and FIG. 3, the driving method of the liquid crystal display in this embodiment includes the following steps:

First, as shown in step S110 , the frame data displayed by the liquid crystal display in each frame time is recorded, for example, the frame data 50 displayed in the M−1th frame time is recorded.

Next, as shown in step S120 , the frame data displayed in each frame time is compared with the frame data displayed in the previous frame time. For example, before the liquid crystal display displays the frame data 60 of the Mth frame time, it is compared with the frame data 50 of the M-1th frame time to detect whether the frame data 50 and 60 have similar patterns.

Afterwards, as shown in step S130 , the gray scale difference between the maximum brightness and the minimum brightness displayed by the pixels of the liquid crystal display is adjusted within the frame time according to the comparison result. For example, when there is a similar pattern (such as pattern E) in the frame data 50 and 60, the movement amount of the pattern E is calculated, and the luminous amplitude of the backlight of the liquid crystal display within the frame time is changed according to the movement amount. Wherein, the calculation method of the moving amount is, for example, calculating the distance in pixels between the pattern E of the screen data 50 and the pattern E of the screen data 60 . When the amount of movement of the pattern E is greater than zero, it means that the picture data 60 is a dynamic picture, and when the dynamic picture is displayed, the light-emitting amplitude of the backlight of the liquid crystal display in the Mth frame time is adjusted according to the amount of movement (such as shown by line L1). In this way, when displaying dynamic images, the liquid crystal display can achieve an effect similar to the pulsed light-emitting display of a cathode ray tube display, avoid blurring of the image, and further improve the display quality of the dynamic image.

In addition, when the moving amount of the pattern E in the picture data 50 and 60 is zero, or when the picture data 50 and 60 have no similar pattern, then the picture data 60 is classified as a static picture, and the Mth picture of the static picture is displayed. Within a frame time, the luminance of the backlight source of the liquid crystal display does not change (as shown by line L2 ). Therefore, when the liquid crystal display displays a static picture, the problem of picture flickering does not occur, which can make the viewer's eyes more comfortable when viewing the static picture.

It is worth noting that the method of judging whether the liquid crystal display displays dynamic patterns or static patterns can also use the comparison of the gray value difference between the image data in the same area at the Mth frame time and the M−1th frame time. When the gray value difference between the two frame times is large, the picture data is a dynamic picture; when the gray value difference between the two frame times is small, the picture data is a static picture.

In this embodiment, the method for improving the display quality of the liquid crystal display includes adjusting the luminous amplitude of the backlight source of the liquid crystal display, or inserting a black frame into the picture data displayed by the liquid crystal display. The following will describe the two methods respectively.

FIG. 4 is a graph showing the relationship between the luminance of the backlight source of the liquid crystal display and time. Please refer to FIG. 4 , in one embodiment, the method for improving the display quality of the liquid crystal display in the Mth frame time is, for example, adjusting the luminous amplitude of the backlight source. Wherein, since the larger the light-emitting amplitude of the backlight is, the better the performance of the dynamic picture is, so in this embodiment, the light-emitting amplitude of the backlight is positively correlated with the moving amount of the pattern E, for example. Specifically, the method for adjusting the light emitting amplitude of the backlight is, for example, to firstly determine whether the moving amount of the pattern E is greater than a reference value. This reference value can be determined according to requirements, for example, it can be set as a distance of several pixels. When the moving amount of the pattern E is greater than the reference value, the luminous amplitude of the backlight within this frame time is A1 (as shown by line L3), and when the moving amount is smaller than the reference value, the backlight is set at this frame time The luminous amplitude within is A2 (shown by line L4), where A1>A2. In addition, when the movement amount is equal to the reference value, the lighting amplitude of the backlight within the frame time can be between A1 and A2.

Since the luminous amplitude of the backlight can change with the movement of the pattern E, when the movement of the pattern E is greater than the reference value, the luminous amplitude of the backlight is higher, so blurring of the dynamic picture can be avoided, and the picture quality can be improved. In addition, because the movement of the pattern E is relatively large, the viewer will focus on the movement of the pattern E when watching, and thus it is less likely to feel flickering on the screen. On the other hand, when the moving amount of the pattern E is less than the reference value, the luminous amplitude of the backlight is relatively low. Although the animation performance is reduced at this time, the moving amount of the pattern E is not large, and the blurring is not easy to occur, and the viewer is watching It is not easy to feel the flickering of the screen.

In the above-mentioned driving method of the liquid crystal display, the backlight includes, for example, a plurality of sub-light sources, and when the sub-light sources are cold-cathode fluorescent tubes, then the method of adjusting the luminous amplitude of the backlight is to adjust the magnitude of the current passing through these cold-cathode fluorescent tubes.

The above-mentioned backlight source also includes an inverter circuit. The inverter circuit can apply a voltage waveform to the cold cathode fluorescent lamp to adjust the luminous amplitude of the backlight source. 5A to 5E are graphs showing the comparison of the light emission amplitude of the backlight source of the liquid crystal display and the voltage waveform of the inverter circuit. The significance of FIGS. 5A to 5E will be described below.

Please refer to Fig. 5A and Fig. 5B to Fig. 5F (a), where two curves 100 and 200 are respectively shown in each figure, one curve 100 represents the voltage waveform of the inverter circuit, and the other curve 200 is The glow amplitude of the backlight. 5B to 5F (b) also show two curves 100 and 300 respectively, wherein one curve 100 represents the voltage waveform of the inverter circuit, and the other curve 300 represents the luminous amplitude observed by human eyes. As illustrated in FIG. 5F , the luminous amplitude of the backlight source is different from the luminous amplitude observed by the human eye, which is because the human eye has the function of a low pass filter. However, the luminous amplitude of the backlight source in FIG. 5F(a) is low-pass filtered to form the luminous amplitude observed by human eyes in FIG. 5F(b). If this feature is utilized and the waveform of the inverter circuit is adjusted, the luminous amplitude of the backlight can be changed, thereby allowing the user to observe different light intensities.

Please refer to FIG. 5A to FIG. 5F again, the voltage waveform is divided into a plurality of positive half cycles and a plurality of negative half cycles. The voltage value of the positive half cycle is greater than zero, and the voltage value of the negative half cycle is less than zero. It is worth mentioning that the method for adjusting the luminous amplitude of the backlight source can be realized by adjusting the voltage waveform of the inverter circuit. For example, please refer to FIG. 5A , the method of adjusting the voltage waveform of the inverter circuit is, for example, to keep the maximum voltage amplitude value and the minimum voltage amplitude value of the voltage waveform unchanged, and to generate multiple negative phases in the positive half cycle of the voltage waveform. Pulse, generating multiple positive pulses in the negative half cycle of the voltage waveform. Here, a positive-going pulse refers to a pulse with a rising voltage, and a negative-going pulse refers to a pulse with a falling voltage. Of course, as shown in Fig. 5B to Fig. 5F, the method of adjusting the luminous amplitude of the backlight is to keep the maximum and minimum voltage amplitude values of the voltage waveform unchanged, and generate multiple negative voltage amplitudes in the positive half cycle of the voltage waveform. Voltage pulses, generating multiple positive voltage pulses in the negative half cycle of the voltage waveform. It should be noted that the voltage value of the positive voltage pulse mentioned here is greater than zero, and the voltage value of the negative voltage pulse is less than zero.

From FIG. 5A to FIG. 5F one by one, it can be observed that after changing the voltage waveform of the inverter circuit, the luminous amplitude of the light source and the luminous amplitude observed by the human eye do change.

In the prior art, in order to adjust the luminous amplitude of the backlight, more than two inverter circuits are usually arranged in the backlight. By driving multiple inverter circuits to apply voltages with different maximum voltage amplitudes and minimum voltage amplitudes to the cold cathode fluorescent lamps, the luminous amplitude of the backlight can be changed. In this embodiment, since the method of adjusting the luminous amplitude of the backlight is to keep the maximum voltage amplitude and the minimum voltage amplitude of the voltage waveform unchanged, only one set of inverter circuits need to be arranged in the backlight, so the production The cost of the backlight is lower.

In addition, in the driving method of the above-mentioned liquid crystal display, when the sub-light source is an array of light-emitting diodes, the method of adjusting the light-emitting amplitude of the backlight module is to adjust the magnitude of the current passing through these light-emitting diodes or to adjust the light-emitting diodes of these light-emitting diode arrays. number.

In a preferred embodiment of the present invention, when the backlight source is a scanning backlight source, the multiple sub-light sources of the backlight source corresponding to different areas of the liquid crystal display are periodically switched on and off. At this time, the method of adjusting the light emitting amplitude of the backlight is not only adjusting the light emitting amplitude of all sub-light sources as described above, but also only adjusting the light emitting amplitude of the sub-light sources in the block where the pattern E is located. In other words, the method for adjusting the light emission amplitude of the backlight is, for example, to determine whether the moving amount of the pattern E is greater than the above-mentioned reference value. When the movement amount is greater than the reference value, the sub-light source of the block corresponding to the pattern E of the backlight source has a luminous amplitude of A1 in the Mth frame time; when the movement amount is smaller than the reference value, the backlight source corresponds to the pattern E The light emitting amplitude of the sub-light source in the block is A2 in the Mth frame time, where A1>A2. In addition, when the movement amount is equal to the reference value, the lighting amplitude of the backlight within the frame time can be between A1 and A2.

Similarly, if the sub-light sources are CCFLs and the backlight includes an inverter circuit, then the voltage waveform of the inverter circuit can also be adjusted to achieve the purpose of changing the luminous amplitude of the scanning backlight. Since the method and advantages of adjusting the luminous amplitude of the scanning backlight are similar to those mentioned above, those skilled in the art can extend it accordingly, so it is not repeated here.

In this embodiment, the method for improving the display quality of the liquid crystal display in the Mth frame time may also be to insert a black picture into the picture data displayed in the Mth frame time, that is, in the Mth frame time Input a low-gray-scale picture data during a certain period to obtain an effect similar to a pulsed light display. Wherein, the gray value of the inserted black frame is negatively correlated with the movement amount of the pattern E, for example. For example, the method of inserting a black frame is to first determine whether the movement amount is greater than the above-mentioned reference value. When the amount of movement is greater than the reference value, a first black frame is inserted, and when the amount of movement is smaller than the reference value, a second black frame is inserted, wherein the gray value of the second black frame is higher than that of the first black frame degree value. In addition, when the movement amount is equal to the reference value, the grayscale value of the inserted black frame may be between the grayscale values of the first black frame and the second black frame.

Because the grayscale value of the inserted black picture can change with the movement of the pattern E, when the movement of the pattern E is greater than the reference value, the grayscale value of the black picture is low, so the blurring of the dynamic picture can be avoided. And then improve the picture quality. In addition, because the movement of the pattern E is relatively large, the viewer will focus on the movement of the pattern E when watching, and thus it is less likely to feel flickering on the screen. On the other hand, when the moving amount of the pattern E is smaller than the reference value, the gray value of the black screen is higher. Although the animation performance is reduced at this time, because the moving amount of the pattern E is not large, blurring is not easy to occur, and the viewer It is not easy to feel the screen flicker when viewing. In addition, since the black frame is inserted through the scanning wiring of the liquid crystal display, the black frame can be inserted into the entire frame data, or only inserted into the partial frame data of the display pattern E.

It is worth mentioning that in this embodiment, in order to make up for the effect of the insertion of the black picture on the brightness of the picture displayed by the liquid crystal display, before inserting the black picture, for example, the gray level of the picture data displayed in the Mth frame time will be increased first. value. In addition, in this embodiment, it is also possible to increase the luminous intensity of the backlight in the Mth frame time to compensate for the effect of the insertion of the black screen on the brightness of the screen displayed by the liquid crystal display.

In terms of the spirit of the present invention, whether it is adjusting the luminous amplitude of the backlight source or inserting a black screen, the liquid crystal display can choose pulse-like driving or holding driving according to the nature of the picture displayed by the liquid crystal display. That is, when the picture data displayed by the LCD is a dynamic picture, choose to use the pulse-like driving method; and when the picture data displayed by the LCD is a static picture, choose to use the holding method to drive. Wherein, as the moving degree of the picture is different, the gray value difference between the maximum brightness and the minimum brightness displayed by the same pixel in each frame time will also be different accordingly. That is, the greater the movement degree of the picture, the greater the gray value difference between the maximum brightness and the minimum brightness displayed by the same pixel in each frame time; and when the picture is still, the gray value displayed by the same pixel in each frame time The maximum brightness is equal to the minimum brightness.

On the other hand, the judgment method of choosing pulse-like or hold-type to drive the liquid crystal display, in addition to whether the picture data is a dynamic picture or a static picture, can also be selected according to the monotony or complexity of the picture data. Drive the LCD display. The so-called monotony or complexity of the picture data refers to the relationship between the gray values displayed by each pixel in the same picture data. When the gray values displayed by the pixels of a picture data are similar, it means that the picture data is monotonous, and the liquid crystal display is driven by the hold mode; when the gray values displayed by the pixels of a picture data vary greatly, it means that If the picture data is complex, choose to drive the liquid crystal display in a pulse-like mode.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection is based on the claims of the present invention.

Claims (20)

1. the driving method of a LCD is suitable for driving a LCD, and the driving method of this LCD comprises:

Write down this LCD shown picture data in each frame time;

Compare shown picture data in picture data shown in each frame time and former frame time; And

In this frame time, adjust the shown high-high brightness of the pixel of this LCD and the gray value differences of minimum brightness according to comparative result.

2. the driving method of LCD as claimed in claim 1, wherein this LCD has a backlight, and the method for adjusting the gray value differences of shown high-high brightness of the pixel of this LCD and minimum brightness comprises the luminous amplitude of adjusting this backlight.

3. the driving method of LCD as claimed in claim 2, the method for wherein adjusting the luminous amplitude of this backlight comprises:

Judge that the picture data in this frame time is dynamic menu or tableaux; And

When if this picture data is dynamic menu, then adjusting this luminous amplitude that comes from this frame time backlight is A1, and when being tableaux as if this picture data, then adjusting this luminous amplitude that comes from this frame time backlight is A2, wherein A1＞A2.

4. the driving method of LCD as claimed in claim 2, the method for wherein adjusting the luminous amplitude of this backlight comprises:

Judge that the picture data in this frame time is complicated or dull; And

When if this picture data is complexity, then adjusting this luminous amplitude that comes from this frame time backlight is A1, and when being dullness as if this picture data, then adjusting this luminous amplitude that comes from this frame time backlight is A2, wherein A1＞A2.

5. the driving method of LCD as claimed in claim 2, wherein this backlight comprises a plurality of cathode fluorescent tubes, and the method for adjusting the luminous amplitude of this backlight comprises and adjusts the size of current that feeds described cathode fluorescent tube.

6. the driving method of LCD as claimed in claim 5, wherein this backlight also comprises an inverter circuit, be suitable for applying a voltage waveform in described cathode fluorescent tube to adjust the luminous amplitude of this backlight, this voltage waveform is divided into a plurality of positive half cycles and a plurality of negative half period, and the method for adjusting the luminous amplitude of this backlight comprises this voltage waveform of adjusting this inverter circuit.

7. the driving method of LCD as claimed in claim 6, the method of wherein adjusting this voltage waveform comprises that the maximum voltage amplitude and the minimum voltage amplitude that keep this voltage waveform are constant, and in the described positive half cycle of this voltage waveform, produce a plurality of negative voltage pulses, produce a plurality of positive voltage pulses in the described negative half period of this voltage waveform.

8. the driving method of LCD as claimed in claim 6, the method of wherein adjusting this voltage waveform comprises that the maximum voltage amplitude and the minimum voltage amplitude that keep this voltage waveform are constant, and in the described positive half cycle of this voltage waveform, produce a plurality of negative-going pulses, produce a plurality of direct impulses in the described negative half period of this voltage waveform.

9. the driving method of LCD as claimed in claim 2, wherein this backlight comprises a plurality of light emitting diode matrixs, and the method for adjusting the luminous amplitude of this backlight module comprises and adjusts size of current that feeds described light emitting diode or the number of adjusting the lumination of light emitting diode of described light emitting diode matrix.

10. the driving method of LCD as claimed in claim 1, wherein this LCD has one scan formula backlight, it comprises a plurality of sub-light sources, correspond respectively to this different blocks of LCD, and described sub-light source periodically is driven, and the method for adjusting the gray value differences of shown high-high brightness of the pixel of this LCD and minimum brightness in this frame time comprises:

The picture data of judging each block in this frame time is dynamic menu or tableaux; And

When if this picture data is dynamic menu, then making this scanning type backlight is A1 to the luminous amplitude of sub-light source in this frame time that should block, when if this picture data is tableaux, then making this scanning type backlight is A2, wherein A1＞A2 to the luminous amplitude of sub-light source in this frame time that should block.

11. the driving method of LCD as claimed in claim 1, wherein this LCD has one scan formula backlight, it comprises a plurality of sub-light sources, correspond respectively to this different blocks of LCD, and described sub-light source periodically is driven, and the method for adjusting the gray value differences of shown high-high brightness of the pixel of this LCD and minimum brightness in this frame time comprises:

The picture data of judging each block in this frame time is complicated or dull; And

When if this picture data is complexity, then making this scanning type backlight is A1 to the luminous amplitude of sub-light source in this frame time that should block, when if this picture data is dullness, then making this scanning type backlight is A2, wherein A1＞A2 to the luminous amplitude of sub-light source in this frame time that should block.

12. the driving method of LCD as claimed in claim 1, also be included in and insert black picture in the picture data shown in this frame time, and the method for adjusting the gray value differences of shown high-high brightness of the pixel of this LCD and minimum brightness comprises the gray-scale value of the black picture that adjustment is inserted.

13. the driving method of LCD as claimed in claim 12, the method for wherein inserting black picture comprises:

Judge that the picture data in this frame time is dynamic menu or tableaux; And

When if this picture data is dynamic menu, then insert one first black picture, when being tableaux, then insert one second black picture as if this picture data, wherein gray-scale value of this second black picture is higher than the gray-scale value of this first black picture.

14. the driving method of LCD as claimed in claim 12, the method for wherein inserting black picture comprises:

Judge that the picture data in this frame time is complicated or dull; And

When if this picture data is complexity, then insert one first black picture, when being dullness, then insert one second black picture as if this picture data, wherein gray-scale value of this second black picture is higher than the gray-scale value of this first black picture.

15. driving method as the described LCD of arbitrary claim in claim 13 or 14, wherein when inserting the black picture of this first black picture or this second, in the data of partial picture at least of display pattern, insert this first black picture or this second black picture.

16., wherein before inserting this first black picture or this second black picture, also comprise the gray-scale value that improves picture data shown in this frame time as the driving method of the described LCD of arbitrary claim in claim 13 or 14.

17. driving method as the described LCD of arbitrary claim in claim 13 or 14, wherein this LCD has a backlight, and also comprises this luminous intensity that comes from this frame time backlight of raising before inserting this first black picture or this second black picture.

18. a LCD has:

One display panel; And

But the backlight of a periodic switch, wherein, the luminance difference of the high-high brightness of this backlight and minimum brightness can be with the characteristic adjustment of display frame in each cycle.

19. LCD as claimed in claim 18, wherein this picture characteristic is meant dynamic menu or tableaux.

20. LCD as claimed in claim 18, wherein this picture characteristic is meant complicated picture or dull picture.

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