CN107221296B - Overdrive method, timing controller and display - Google Patents

Abstract

An over-driving method, timing controller and display. The over-driving method is suitable for displays. This over-driving method includes the following steps: compare the content of the current frame and the next frame of the image to obtain the gray-scale change of one pixel of the image; find out the gray-scale change corresponding to the first over-driving gray-scale comparison table the first over-driven gray scale, and find the second over-driven gray scale corresponding to the gray scale change from the second over-driven gray scale comparison table; and based on the first over-driven gray scale and the second over-driven gray scale, The interpolation method calculates the third over-driven gray level corresponding to the current update rate, which is used as the target over-driven gray level of the pixel in the next frame. The invention also discloses a timing controller and a display.

Description

Overdrive method, timing controller and display

technical field

The invention relates to related technologies in the display field, in particular to an overdrive method, a timing controller and a display.

Background technique

Due to the slow response time of liquid crystals, afterimages will occur under dynamic images, resulting in blurred images in the visual sense. Therefore, overdrive (Over Drive, OD) technology is applied to the drive of liquid crystals. This technology It is used to increase the liquid crystal cross-voltage to speed up its response time, thereby reducing dynamic afterimage. The traditional overdrive technology selects an appropriate overdrive grayscale intensity according to an overdrive grayscale look-up table (OD Look-Up Table, ODLUT) corresponding to a single frame rate. Since the size of the grayscale value is positively correlated with the size of the liquid crystal cross-voltage, increasing the gray-scale value means increasing the liquid crystal cross-voltage, thereby speeding up the response time of the liquid crystal.

However, limited by the storage space of the hardware, the traditional method only uses a few overdrive grayscale comparison tables, which makes the monitor prone to overdrive when the frame rate changes continuously. On the other hand, if a large number of overdrive grayscale comparison tables are used to correspond to different frame update rates, the large number of overdrive grayscale comparison tables will not only consume hardware storage space, but also increase the timing controller (Timing controller). ) The number of logic gates increases the cost.

Contents of the invention

The technical problem to be solved by the present invention is to provide an overdrive method, which can select an appropriate overdrive grayscale intensity under continuous changes in the frame update rate without requiring a large number of overdrive grayscale comparison tables.

Another object of the present invention is to provide a timing controller using the above-mentioned overdrive method.

Another object of the present invention is to provide a display device corresponding to the above overdriving method.

In order to achieve the above purpose, the present invention provides an overdrive method suitable for displays. The overdrive method includes the following steps: receiving an image; obtaining the current update rate of the image; comparing the content of the current frame and the next frame of the image to obtain the grayscale change of one pixel of the image; comparing the grayscale from the first overdrive Look up the first overdrive gray scale corresponding to the above gray scale change, and find out the second overdrive gray scale corresponding to the above gray scale change from the second overdrive gray scale comparison table, wherein the first overdrive gray scale The comparison table records the multiple overdrive gray levels corresponding to various gray scale changes at the first frame update rate, and the second overdrive gray scale comparison table records the multiple gray scale changes corresponding to the second frame update rate. Corresponding to a plurality of overdrive gray levels, and the first frame update rate and the second frame update rate are different from the current update rate; and according to the first overdrive gray level and the second overdrive gray level, calculate the current The third overdrive gray scale corresponding to the update rate is used as the target overdrive gray scale of the pixel in the next frame.

The invention also provides a timing controller suitable for a display. The timing controller includes a data comparison unit and an overdrive gray scale calculation unit. The data comparing unit is used for comparing the contents of the current frame and the next frame of the image, so as to obtain the gray scale change of one pixel of the image. The overdrive grayscale calculation unit is used to find out the first overdrive grayscale corresponding to the above grayscale change from the first overdrive grayscale comparison table, and find out the above grayscale change from the second overdrive grayscale comparison table. The corresponding second overdrive grayscale, and then calculate the third overdrive grayscale corresponding to the current update rate of the image by interpolation method according to the first overdrive grayscale and the second overdrive grayscale, as the above pixel The target for the next frame overdrives the gray scale. The first overdrive grayscale comparison table records multiple overdrive grayscales corresponding to various grayscale changes at the first frame update rate, and the second overdrive grayscale comparison table records at the second frame update rate , a plurality of overdrive gray levels corresponding to various gray level changes, and both the first frame update rate and the second frame update rate are different from the current update rate.

The present invention also provides a display, which includes a display panel, a data driving unit and a timing controller. The display panel has one pixel. The data driving unit is electrically coupled to the pixels. As for the timing controller, it is used to provide different overdrive voltages for the above-mentioned pixels through the data driving unit at different frame refresh rates, wherein the provided overdrive voltage has a linear relationship with the frame refresh rate.

Technical effect of the present invention is:

Because the present invention uses the interpolation method to calculate the overdrive gray level corresponding to the current update rate based on the first overdrive gray level corresponding to the first frame update rate and the second overdrive gray level corresponding to the second frame update rate. Therefore, in the best case, the present invention only needs two overdrive grayscale comparison tables corresponding to two different picture update rates, so that the appropriate overdrive grayscale strength can be selected under the continuously changing picture update rate. , and can achieve the effect of saving hardware cost.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

Figure 1 is a relationship curve between liquid crystal transvoltage variation and liquid crystal rotation rate;

Fig. 2 is the relationship curve between liquid crystal cross voltage and liquid crystal reaction time;

FIG. 3 is one of the linear interpolation operations used to illustrate the overdrive grayscale;

FIG. 4 is another linear interpolation operation used to illustrate the overdrive gray scale;

Fig. 5 is another relationship curve between liquid crystal cross voltage and liquid crystal reaction time;

FIG. 6 is a flowchart of an overdrive method according to an embodiment of the present invention;

FIG. 7 is a block diagram of an internal circuit of a timing controller according to an embodiment of the invention.

Among them, reference signs

S61～S65: steps

10: Timing controller

11: Data input processing unit

12: Frame buffer

13: Data comparison unit

14: Update rate detection unit

15: Overdrive grayscale calculation unit

16: Overdrive processing unit

17: Output processing unit

In: video

Out: output

Detailed ways

Below in conjunction with accompanying drawing, structural principle and working principle of the present invention are specifically described:

FIG. 1 is a relationship curve between liquid crystal transvoltage variation and liquid crystal rotation rate. As shown in FIG. 1 , the abscissa of FIG. 1 refers to the amount of liquid crystal transvoltage change in percentage, and the ordinate refers to the slew rate of the liquid crystal. The so-called liquid crystal rotation rate is pixel brightness change/liquid crystal response time, wherein the unit of liquid crystal response time is millisecond (ms). In addition, the point P1 shown in Figure 1 represents the gray scale change from gray scale value L64 to gray scale value L96, the point P2 represents the gray scale change from gray scale value L64 to gray scale value L128, and the point P3 represents the gray scale change from The gray scale value L64 is raised to the gray scale value L160, the P4 point represents the gray scale change from the gray scale value L64 to the gray scale value L192, the P5 point represents the gray scale change from the gray scale value L64 to the gray scale value L224, and the P6 point It represents the change of the gray scale from the gray scale value L64 to the gray scale value L255. As can be seen from FIG. 1 , since the liquid crystal has a characteristic of relatively slow response speed, there is a moderate relationship between the liquid crystal transvoltage change and the liquid crystal rotation rate. As shown in Figure 1, it can be seen that a straight line can be seen between P1 and P2, and between P2 and P3, P3 and P4, P4 and P5, P5 and P6 are also straight lines. Can be regarded as a straight line. That is to say, between any of the above two points, the amount of change in the voltage across the liquid crystal is in a linear relationship with the change in the rotation rate of the liquid crystal. The values of liquid crystal transvoltage change and liquid crystal rotation rate at points P1, P2, P3, P4, P5, and P6 in FIG. 1 can be obtained by measurement.

FIG. 2 is a relationship curve between liquid crystal voltage and liquid crystal response time. Please refer to FIG. 1 and FIG. 2 at the same time. It can be seen from FIG. 1 that if the variation of the liquid crystal cross-voltage is within a certain range, then there will be a linear relationship between the variation of the liquid crystal cross-voltage and the rotation rate of the liquid crystal. This means that in the linear range, the rotation rate of the liquid crystal will increase with the increase of the voltage across the liquid crystal. According to the above conclusions, it can be seen that in Fig. 2, when the liquid crystal cross-voltage variation increases from D to A, the liquid crystal rotation rate also increases from D' to A'. Therefore, assuming that the frame update rate is 120 Hz, if the amount of change across the liquid crystal voltage is A, the liquid crystal can increase from the initial gray scale value LS to the target gray scale value LT within the time period of (t2-t1). And the rotation rate of the liquid crystal at this time is A'. And assuming that in the case of a frame update rate of 60 Hz, if the amount of change across the liquid crystal voltage is D, the liquid crystal can increase from the initial gray scale value LS to the target gray scale value LT within the time period of (t3-t1), and The liquid crystal rotation rate at this time is D'. If the above-mentioned 120Hz and 60Hz are the upper limit frame refresh rate and the lower limit frame refresh rate that the monitor can support respectively, then you can find out from the two overdrive grayscale comparison tables corresponding to the two frame refresh rates. The initial grayscale value LS is raised to the overdrive grayscale required by the target grayscale value LT, and then the overdrive grayscale required by the current update rate is calculated by interpolation based on the two found overdrive grayscales, Overdrive the gray level as the target of the corresponding pixel in the next frame. Take Figure 3 for further explanation.

FIG. 3 is used to illustrate the linear interpolation operation of the overdrive gray scale, please refer to FIG. 3 . For example, if a pixel needs to be raised from the grayscale value L64 to the grayscale value L160, after checking the overdrive grayscale comparison table corresponding to the lower limit frame update rate of 60Hz, it can be known that the required overdrive grayscale size of this pixel is The grayscale value is L164, and the overdrive grayscale comparison table corresponding to the upper limit frame update rate of 120Hz shows that the overdrive grayscale size required by this pixel is the grayscale value L183. When the update rate is 100Hz, an interpolation method can be used to obtain the size of the overdrive gray scale required by the pixel when the current update rate is 100Hz. There are two calculation formulas available for the above interpolation method, and the user can choose one to use. The two calculation formulas are as follows:

Among them, Y is the size of the overdrive gray scale required at the current refresh rate, OD _FR1 is the size of the overdrive gray scale required at the first frame refresh rate (in this example, the lower limit frame refresh rate), and X is the current refresh rate, FR1 is the first frame refresh rate (in this example, the lower limit frame refresh rate is 60Hz), and ΔOD is the ratio of the two overdrive gray levels required under the first frame refresh rate and the second frame refresh rate Difference, ΔFR is the difference between the first frame refresh rate and the second frame refresh rate, OD _FR2 is the size of the overdrive gray scale required under the second frame refresh rate (in this example, the upper limit frame refresh rate), As for FR2, it is the second frame refresh rate (in this example, the upper limit frame refresh rate is 120 Hz).

Although in the above description, the grayscale value of the pixel is raised as an example, this is not intended to limit the present invention. When the grayscale value of the pixel is lowered, the above-mentioned interpolation method can also be applied, as in As shown in FIG. 4, FIG. 4 is used to illustrate the linear interpolation operation of the overdrive gray scale in this case. Since the linear interpolation operation shown in FIG. 4 is similar to the linear interpolation operation shown in FIG. 3 , details will not be repeated here. Of course, in addition to the interpolation method, the extrapolation method can also be used to calculate the required overdrive gray scale. Taking Figure 3 again as an example, the display can first look up the table to obtain the two overdrive gray levels required at the screen update rate of 60Hz and 80Hz, and then use extrapolation to calculate the required overdrive gray level at the current update rate of 100Hz. Drive grayscale. In this case, the first frame refresh rate can be one of the minimum frame refresh rate and the maximum frame refresh rate supported by the above-mentioned monitor, and the second frame refresh rate is between the minimum frame refresh rate and the maximum frame refresh rate. rate between.

In addition, if the image is in the case of high resolution (Pixel Per Inch, PPI) and high update rate, the excessive overdrive can be moderately tolerated if the human eye is not easy to detect the phenomenon of overdrive due to the small blurred edge width Phenomenon, so that the elimination of dynamic afterimage can get better results. In this case, interpolation or extrapolation can be performed with reference to the relationship curve shown in FIG. 5 to obtain the desired overdrive gray scale. FIG. 5 is another relationship curve between liquid crystal cross voltage and liquid crystal response time.

According to the above teachings, those skilled in the art should be able to summarize some basic operation steps of the above overdrive method, as shown in FIG. 6 . FIG. 6 is a flowchart of an overdriving method according to an embodiment of the invention. Please refer to Fig. 6, this overdrive method comprises the following steps: receive an image (as shown in step S61); Obtain the current update rate of this image (as shown in step S62), and the current update rate of this image can be provided by the system Relevant parameters, or obtain by calculating the interval time of the front and back frames; compare the content of the current frame and the next frame of the above-mentioned image to obtain the gray scale change of one pixel of the image (as shown in step S63); from the first Find out the first overdrive grayscale corresponding to the above-mentioned grayscale change from the overdrive grayscale comparison table, and find out the second overdrive grayscale corresponding to the above grayscale change from the second overdrive grayscale comparison table (as in step S64), wherein the first overdrive grayscale comparison table records a plurality of overdrive grayscales corresponding to various grayscale changes under the first frame update rate, and the second overdrive grayscale comparison table is recorded at Under the two picture update rates, multiple overdrive gray levels corresponding to various gray scale changes, and the first picture update rate and the second picture update rate are different from the current update rate; and according to the first overdrive gray level and the second picture update rate The second overdrive gray level is used to calculate the third overdrive gray level corresponding to the current update rate by an interpolation method as the target overdrive gray level of the pixel in the next frame (as shown in step S65 ).

FIG. 7 is a block diagram of an internal circuit of a timing controller according to an embodiment of the present invention, and the timing controller is suitable for a display. As shown in Figure 7, the timing controller 10 includes a data input processing unit 11, a frame buffer (framebuffer) 12, a data comparison unit 13, an update rate detection unit 14, an overdrive gray scale calculation unit 15, an overdrive processing unit 16 and an output processing unit 17. The data input processing unit 11 is used to receive the image In, and transmit the processed image In to the update rate detection unit 14 , the frame buffer 12 , the data comparison unit 13 and the overdrive processing unit 16 . The frame buffer 12 is used to store the current frame of the image In, and provide it to the data comparison unit 13, so that the data comparison unit 13 compares the content of the current frame of the image In with the next frame of the image In, and then obtains the content of the image In. The gray scale of one of the pixels changes. The update rate detection unit 14 is used to receive the relevant parameters of the current update rate provided by the data input processing unit 11 or to calculate the current update rate based on the interval time of the previous and subsequent frames.

The overdrive grayscale calculation unit 15 is used to receive the current update rate of the image In obtained by the update rate detection unit 14 and the grayscale change of the above-mentioned pixels obtained by the data comparison unit 13, and use the information from the first overdrive grayscale comparison table Find out the first overdrive gray scale corresponding to the above gray scale change, and find out the second overdrive gray scale corresponding to the above gray scale change from the second overdrive gray scale comparison table, and then according to the first overdrive gray scale Calculate the third overdrive gray level corresponding to the current update rate of the image by interpolation with the second overdrive gray level, as the target overdrive gray level of the pixel in the next frame, and use the calculated target overdrive The gray scale value is sent to the overdrive processing unit 16 . The overdrive processing unit 16 sets the overdrive grayscale of the pixel for the image In transmitted from the data input processing unit 11 according to the received value of the target overdrive grayscale, and then processes it through the output processing unit 17 as The output of the timing controller 10. In this way, the data driving unit (not shown) can generate an overdrive voltage of a corresponding magnitude according to the relevant information about the required overdrive gray scale of the pixel output by the timing controller 10, and the generated overdrive voltage A voltage is provided to the pixel so that the pixel has a corresponding voltage across the liquid crystal. The above-mentioned first overdrive grayscale comparison table records multiple overdrive grayscales corresponding to various grayscale changes at the first frame update rate, while the second overdrive grayscale comparison table records the multiple overdrive grayscales corresponding to the second frame update rate. In this case, a plurality of overdrive gray levels corresponding to various gray level changes, and both the first frame update rate and the second frame update rate are different from the current update rate. Of course, the overdrive grayscale calculation unit 15 can also use three overdrive grayscale comparison tables corresponding to three different frame refresh rates, for example, corresponding to the upper limit frame refresh rate, the lower limit frame refresh rate, and the range between the above two refresh rates. A picture update rate is used to calculate the overdrive gray scale required at the current update rate to achieve a more accurate effect.

In addition, based on the above teachings, the present invention also proposes a display, which mainly includes a display panel (not shown), a data driving unit (not shown) and the aforementioned timing controller 10 . The display panel has a pixel, and the data driving unit is electrically coupled to the pixel. As for the timing controller 10 , it is used to provide different overdrive voltages for the above-mentioned pixels through the data driving unit at different frame refresh rates, wherein the provided overdrive voltage has a linear relationship with the frame refresh rate.

To sum up, based on the linear relationship between liquid crystal transvoltage variation and liquid crystal rotation rate, the present invention can utilize the first overdrive gray level corresponding to the first frame update rate and the second frame rate corresponding to the second frame update rate. Overdrive grayscale and use interpolation method to calculate the overdrive grayscale corresponding to the current update rate, so that the present invention only needs two overdrive grayscale comparison tables corresponding to two different update rates in the best case. In this way, an appropriate overdrive grayscale intensity can be selected under continuous changes in the update rate, and the effect of saving hardware costs can also be achieved.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should all belong to the protection scope of the appended claims of the present invention.

Claims (7)

1. An overdrive method for a display, the overdrive method comprising:

receiving an image;

obtaining a current update rate of the image;

comparing the content of a current picture and the content of a next picture of the image to obtain a gray scale change of one pixel of the image;

finding out a first overdrive gray scale corresponding to the gray scale change from a first overdrive gray scale comparison table, and finding out a second overdrive gray scale corresponding to the gray scale change from a second overdrive gray scale comparison table, wherein the first overdrive gray scale comparison table is recorded under a first picture update rate, a plurality of overdrive gray scales corresponding to a plurality of gray scale changes, the second overdrive gray scale comparison table is recorded under a second picture update rate, a plurality of overdrive gray scales corresponding to a plurality of gray scale changes, and both the first picture update rate and the second picture update rate are different from the current update rate; and

and calculating a third overdrive gray scale corresponding to the current update rate by an interpolation method according to the first overdrive gray scale and the second overdrive gray scale to serve as a target overdrive gray scale of the pixel in the next picture.

2. The method as claimed in claim 1, wherein the first frame rate and the second frame rate are a lower limit frame rate and an upper limit frame rate respectively supported by the display.

3. The method as claimed in claim 1, wherein the first frame rate is one of a lower frame rate and an upper frame rate supported by the display, and the second frame rate is between the lower frame rate and the upper frame rate.

4. A timing controller for a display, the timing controller comprising:

a data comparing unit for comparing the content of a current frame and a next frame of an image to obtain a gray scale change of one pixel of the image; and

an overdrive gray scale calculation unit, for finding out a first overdrive gray scale corresponding to the gray scale change from a first overdrive gray scale comparison table, and finding out a second overdrive gray scale corresponding to the gray scale change from a second overdrive gray scale comparison table, and further calculating a third overdrive gray scale corresponding to a current update rate of the image by an interpolation method according to the first overdrive gray scale and the second overdrive gray scale, so as to be used as a target overdrive gray scale of the pixel in a next frame;

the first overdrive gray scale comparison table records a plurality of overdrive gray scales corresponding to a plurality of gray scale changes under a first picture update rate, the second overdrive gray scale comparison table records a plurality of overdrive gray scales corresponding to a plurality of gray scale changes under a second picture update rate, and both the first picture update rate and the second picture update rate are different from the current update rate.

5. The timing controller of claim 4, wherein the first frame rate and the second frame rate are a lower limit frame rate and an upper limit frame rate supported by the display, respectively.

6. The timing controller as claimed in claim 4, wherein the first frame rate is one of a lower frame rate and an upper frame rate supported by the display, and the second frame rate is between the lower frame rate and the upper frame rate.

7. A display, comprising:

a display panel having a pixel;

a data driving unit electrically coupled to the pixel; and

a timing controller as claimed in any one of the preceding claims 4 to 6, for providing different overdrive voltages for the pixel through the data driving unit at different frame update rates, wherein the overdrive voltages provided are in a linear relationship with the frame update rate.