TW202001834A - Display device and method for displaying the same - Google Patents

Abstract

A method for displaying a display device is provided. The method includes receiving an input image signal including plural pixel signals; determining first to third color frame brightness values by calculating first to third color initial brightness values of each of the pixel signals; generating a backlight signal group by calculating the first to third color frame brightness values; generating a sub-pixel signal group corresponding to each of the pixel signals by calculating the first to third color frame brightness values and the first to third color initial brightness values of each of the pixel signals; controlling first to fourth color light sources of a backlight module according to the backlight signal group; and controlling first to fourth color sub-pixels of a liquid crystal unit according to the sub-pixel signal group

Description

Display device and display method

The invention relates to a display device and a display method thereof.

Generally, a liquid crystal display panel includes a plurality of sub-pixels for displaying different colors. For example, an RGB display has three sub-pixels of red, green, and blue; a CMY (cyan, magenta, yellow) display has cyan, magenta, and yellow sub-pixels. In addition to the basic three-primary-color display, a wide-color gamut liquid crystal display also came into being. For example, an RGBW display has red, green, blue, and blank sub-pixels.

However, due to the small red, green and blue sub-pixel area of the wide color gamut LCD, the brightness of the solid color is dimmed and the brightness of the white screen is too high, resulting in poor image quality. To supplement the brightness of solid colors, the brightness of the backlight needs to be increased, which also increases power consumption. Therefore, how to improve the image quality of the display device and avoid excessive power consumption is the goal of continuous efforts of those skilled in the art.

In various embodiments of the present invention, the input three-color signal is converted to a four-color signal, so that the image quality can be achieved in a wide color gamut (such as RGBW) LCD display and even better than a solid color (such as RGB) LCD display. effect. The signal conversion process is combined with digital dynamic backlight operation, so that a wide color gamut (such as RGBW) LCD signal can be matched with a multi-primary color backlight signal. In addition to improving the problem of darker solid colors and brighter white images, the color gamut is improved. It can achieve a more power-saving effect than ordinary solid color (such as RGB) liquid crystal displays, and can take into account the requirements for image quality and power saving.

According to some embodiments of the present invention, a display method of a display device includes receiving an input image signal, wherein the input image signal includes a plurality of pixel signals; calculating the initial brightness value of the first color and the second brightness value of each pixel signal And the initial brightness value of the third color to determine the brightness value of the first color screen, the brightness value of the second color screen and the brightness value of the third color screen; calculate the brightness value of the first color screen, the brightness value of the second color screen and the third color screen Brightness value to generate the backlight signal group; calculate the brightness value of the first color screen, the brightness value of the second color screen, the brightness value of the third color screen and the initial brightness value of the first color and the initial brightness value of the second color for each pixel signal And the initial brightness value of the third color to generate the sub-pixel signal group of each pixel signal; the first color light source, the second color light source, the third color light source and the fourth color of the backlight module are controlled by the backlight signal group A light source; and the first dichroic pixel, the second dichroic pixel, the third dichroic pixel and the fourth dichroic pixel of the liquid crystal cell are controlled by the sub-pixel signal group.

In some embodiments, the process of determining the luminance value of the first color picture, the luminance value of the second color picture and the luminance value of the third color picture includes calculating the initial luminance value of the first color and the initial luminance value of the second color for each pixel signal And the initial brightness value of the third color to generate the first-color background brightness value, the second-color background brightness value, and the third-color background brightness value of each pixel signal; and extract the first-color background brightness value of the pixel signal The largest, the largest of the second-color background luminance values, and the third of the third-color background luminance values, respectively, as the first-color image luminance value, the second-color image luminance value, and the third-color image luminance value .

In some embodiments, the display method of the display device further includes reducing the brightness value of the first color screen, the brightness value of the second color screen, and the brightness value of the third color screen before generating the backlight signal group.

In some embodiments, the display method of the display device further includes adjusting the reduction levels of the first-color image brightness value, the second-color image brightness value, and the third-color image brightness value according to the color difference tolerance value.

In some embodiments, the process of generating the backlight signal group includes using the smallest of the first-color image brightness value, the second-color image brightness value, and the third-color image brightness value as the fourth-color backlight brightness signal of the backlight signal group ; Enlarge the first-color screen brightness value, the second-color screen brightness value and the third-color screen brightness value; and the enlarged first-color screen brightness value, the enlarged second-color screen brightness value and the enlarged third-color screen brightness value; The value is subtracted from the fourth color backlight brightness signal to obtain the first color backlight brightness signal, the second color backlight brightness signal and the third color backlight brightness signal of the backlight signal group, respectively.

In some embodiments, the luminance value of the first color picture, the luminance value of the second color picture, and the luminance value of the third color picture are amplified at the same ratio.

In some embodiments, the fourth color backlight brightness signal is a white light backlight signal.

In some embodiments, the sub-pixel signal group includes a first color pixel gray level signal, a second color pixel gray level signal, a third color pixel gray level signal, and a fourth color pixel gray level signal Signal.

In some embodiments, the generation process of the sub-pixel signal group includes obtaining the first liquid crystal compensation value and the second liquid crystal with the reciprocal of the first-color image brightness value, the second-color image brightness value and the third-color image brightness value, respectively Compensation value and third color liquid crystal compensation value; calculate the minimum of the first color initial brightness value, the second color initial brightness value and the third color initial brightness value of the pixel signal, and the first liquid crystal compensation value and the second liquid crystal compensation The smallest of the value and the third color liquid crystal compensation value to generate the four-color sub-pixel brightness value; and calculate the first color initial brightness value, the second color initial brightness value, the third color initial brightness value, the first color liquid crystal compensation Value, second color liquid crystal compensation value, third color liquid crystal compensation value, and fourth color sub-pixel signal to generate a first color sub-pixel luminance value, a second color sub-pixel luminance value, and a third color sub-pixel pixel Brightness value.

In some embodiments, the generation process of the sub-pixel signal group further includes the first-color sub-pixel brightness value, the second-color sub-pixel brightness value, the third-color sub-pixel brightness value, and the fourth-color sub-pixel brightness value Luminance value, inverse gray scale conversion, to obtain the first color pixel gray level signal, the second color pixel gray level signal, the third color pixel gray level signal and the fourth color pixel gray level signal .

In some embodiments, the grayscale signal of the fourth sub-pixel is a white sub-pixel signal.

In some embodiments, each pixel signal includes a first color initial grayscale signal, a second color initial grayscale signal, and a third color initial grayscale signal. The display method of the display device includes performing grayscale conversion to convert the first color initial grayscale signal, the second color initial grayscale signal and the third color initial grayscale signal of each pixel signal into each pixel signal The initial luminance value of the first color, the initial luminance value of the second color, and the initial luminance value of the third color.

According to some embodiments of the present invention, the display device includes a backlight module, a liquid crystal unit, a signal processing unit, a backlight signal generating unit, a sub-pixel signal generating unit, and a backlight control unit. The backlight module includes a first color light source, a second color light source, a third color light source, and a fourth color light source. The liquid crystal cell is used to display an output image, wherein the liquid crystal cell includes a plurality of pixels, and each pixel includes a first color sub-pixel, a second color sub-pixel, a third color sub-pixel, and a fourth color sub-pixel. The signal processing unit is used to determine the brightness value of the first color screen, the brightness value of the second color screen, and the brightness value of the third color screen according to the plurality of pixel signals of the input image signal. The backlight signal generating unit is used to calculate the luminance value of the first color image, the luminance value of the second color image and the luminance value of the third color image to generate a backlight signal group. The sub-pixel signal generating unit is used for generating a sub-pixel signal group according to the input image signal and the luminance value of the first color picture, the luminance value of the second color picture and the luminance value of the third color picture. The backlight control unit is used to control the backlight module according to the backlight signal group. The liquid crystal control unit is used to control the liquid crystal unit according to the sub-pixel signal group.

In some embodiments, the signal processing unit includes a background brightness calculation unit and a picture brightness determination unit. The background brightness calculation unit is used to receive and process the pixel signal of the input image signal to generate each picture according to the first color initial brightness value, the second color initial brightness value and the third color initial brightness value of each pixel signal The first signal background luminance value, the second color background luminance value and the third color background luminance value of the pixel signal. The picture brightness determining unit is used to extract the largest one of the first color background brightness value of the pixel signal, the largest one of the second color background brightness value of the pixel signal, and the largest one of the third color background brightness value of the pixel signal, Let the brightness values of the first-color picture, the second-color picture and the third-color picture be respectively.

In some embodiments, the sub-pixel signal generating unit is based on the first-color image brightness value, the second-color image brightness value, the third-color image brightness, and the first-color initial brightness value and the second color of each pixel signal The initial luminance value and the initial luminance value of the third color generate a sub-pixel signal group.

In some embodiments, the picture brightness determination unit is further used to perform the following steps: reduce the brightness value of the first color picture, the brightness value of the second color picture, and the brightness value of the third color picture.

In some embodiments, the fourth color light source is a white light source.

In some embodiments, the fourth color sub-pixel is a white sub-pixel.

100‧‧‧Display device

110‧‧‧Backlight module

112a‧‧‧First color light source

112b‧‧‧Second color light source

112c‧‧‧ Third color light source

112d‧‧‧ fourth color light source

120‧‧‧LCD unit

122‧‧‧ pixels

122a‧‧‧ First color pixel

122b‧‧‧Second color pixel

122c‧‧‧ third color pixel

122d‧‧‧ fourth color pixel

130‧‧‧ processor

132‧‧‧ Gray scale processing unit

132G‧‧‧Gray scale conversion unit

132B‧‧‧Background brightness calculation unit

132P‧‧‧Picture brightness determination unit

134‧‧‧Backlight signal generation unit

136‧‧‧ Sub-pixel signal generation unit

136C‧‧‧Calculation unit

136G‧‧‧Inverse Grayscale Conversion Unit

140‧‧‧register

150‧‧‧Backlight control unit

160‧‧‧LCD control unit

LUT‧‧‧Lookup Table

300‧‧‧Method

302~324‧‧‧Step

SI‧‧‧ Input video signal

DIG _ia ‧‧‧ first color grayscale signal

DIG _i ‧‧‧Second color initial grayscale signal

DIG _ic ‧‧‧ third color initial grayscale signal

DIB _ia ‧‧‧ initial brightness value of the first color

DIB _ib ‧‧‧ initial brightness value of the second color

DIB _ic ‧‧‧The initial brightness value of the third color

KB _ia ‧‧‧ First color background brightness value

KB _ib ‧‧‧ Second color background brightness value

KB _ic ‧‧‧The brightness value of the third color background

KB _maxa ‧‧‧ First-color screen brightness value

KB _maxb ‧‧‧ Second-color screen brightness value

KB _maxc ‧‧‧ Brightness value of the third color screen

BLB _w ‧‧‧White backlight brightness signal

BLB _a ‧‧‧ First color backlight brightness signal

BLB _b ‧‧‧ Second color backlight brightness signal

BLB _c ‧‧‧ third color backlight brightness signal

α _a ‧‧‧ First color LCD compensation value

α _b ‧‧‧ Compensation value of the second color LCD

α _c ‧‧‧ Compensation value of the third color LCD

DOB _iw ‧‧‧ White sub-pixel brightness value

DOB _ia ‧‧‧ brightness value of the first dice pixel

DOB _ib ‧‧‧ brightness value of the second color pixel

DOB _ic ‧‧‧ Brightness value of the third color pixel

DOG _iw ‧‧‧White sub-pixel grayscale signal

DOG _ia ‧‧‧ First dice pixel grayscale signal

DOG _ib ‧‧‧ Second color pixel grayscale signal

DOG _ic ‧‧‧ third color pixel grayscale signal

DPG‧‧‧Sub-pixel signal group

BLG‧‧‧Backlight signal group

FIG. 1 is a schematic diagram of a display device according to some embodiments of the present invention.

2 is a block diagram of a display method of a display device according to some embodiments of the present invention.

3A and 3B are flowcharts of the display method of the display device according to some embodiments of the present invention.

4A to 4C are schematic top views of pixels in some embodiments of the present invention.

In the following, a plurality of embodiments of the present invention will be disclosed in the form of diagrams. For the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is to say, in some embodiments of the present invention, these practical details are unnecessary. In addition, for the sake of simplifying the drawings, some conventional structures and elements will be shown in a simple schematic manner in the drawings.

FIG. 1 is a schematic diagram of a display device 100 according to some embodiments of the present invention. 2 is a block diagram of a display method of the display device 100 according to some embodiments of the present invention. The display device 100 includes a backlight module 110, a liquid crystal unit 120, a processor 130, a register 140, a backlight control unit 150, and a liquid crystal control unit 160.

The backlight module 110 is used to provide light L1. The liquid crystal unit 120 is used to display the output image. The processor 130 is coupled to the register 140, the backlight control unit 150, and the liquid crystal control unit 160. The processor 130 is used to receive the input image signal SI to generate the backlight signal group BLG and the sub-pixel signal group DPG according to the input image signal SI, and send the two to the backlight control unit 150 and the liquid crystal control unit 160, respectively. The backlight control unit 150 and the liquid crystal control unit 160 are respectively coupled to the backlight module 110 and the liquid crystal unit 120, so that the backlight control unit 150 controls the backlight module 110 to emit and change the light L1 according to the backlight signal group BLG, and the liquid crystal control unit 160 according to the sub-picture The pixel signal group DPG controls the liquid crystal unit 120 to adjust the transmittance of the light L. The register 140 stores a plurality of look-up tables (Look Up Table; LUT) for the processor 130 to use. In this embodiment, the processor 130 includes a signal processing unit 132, a backlight signal generating unit 134, and a sub-pixel signal generating unit 136 to process the input image signal SI, and its function will be described in detail later.

In this embodiment, the backlight module 110 includes first to fourth color light sources 112a to 112d. For example, the first to fourth color light sources 112a to 112d are red, green, blue, and white light sources, respectively.

In this embodiment, the liquid crystal cell 120 includes a plurality of pixels 122, and each pixel 122 includes first to fourth dichroic pixels 122a to 122d. For example, the first to fourth color sub-pixels 122a-122d are red, green, blue, and white sub-pixels, respectively.

3A and 3B are flowcharts of a display method 300 of a display device according to some embodiments of the present invention. The method 300 includes steps 302-320, where the first to fourth colors are exemplified as red, green, blue, and white (RGBW). Please refer to FIG. 2 in conjunction with FIGS. 3A and 3B to understand the concept of this embodiment.

In this embodiment, an external processing system (such as a computer, not shown) provides an input image signal SI in each frame. The input signal SI is associated with, for example, the gray level value of each pixel in at least one frame of the picture, for example, in the form of a data stream. The input image signal SI includes a plurality of pixel signals DI ₁ to DI _n , which are respectively supplied to the pixels 122 of the liquid crystal unit 120. Here, each pixel signal DI ₁ ~DI _n includes a first color initial grayscale signal DIG _1a ~DIG _na , a second color initial grayscale signal DIG _1b ~DIG _b and a third color initial grayscale signal DIG _1c ~ DIG _nc . In some embodiments, n is the number of pixels 122 of the liquid crystal cell 120, and n is a positive integer greater than 1. For example, if the resolution of the liquid crystal cell 120 of the display device 100 is 1920x1080, n is equal to 2073600. If the resolution of the liquid crystal cell 120 of the display device 100 is 1024 x 768, n is equal to 786432.

First, in step 302, the signal processing unit 132 of the processor 130 receives the input image signal SI, and a gray-scale conversion unit 132G of the signal processing unit 132 is the first for each pixel signal DI ₁ ~DI _n of the input image signal SI The initial gray-scale signal DIG _1a ~DIG _na , the initial gray-scale signal DIG _1b ~DIG _nb of the second color and the initial gray-scale signal DIG _1c ~DIG _{nc of the} third color are converted into gray scales according to "Formula 1" to obtain each The first color initial brightness values DIB _1a to DIB _na of the first pixel signals DI ₁ to DI _n , the second color initial brightness values DIB _1b to DIB _nb, and the third color initial brightness values DIB _1c to DIB _nc . In other words, the first to third color initial gray-scale signals (DIG _ia , DIG _ib , DIG _ic ) of each pixel signal DI _i will be converted into gamma according to "Formula 1", and the gray-scale value will be converted from the signal field Converted to the brightness domain, after conversion will get the initial brightness value of the first to third colors [DIB _ia , DIB _ib , DIB _ic ] between 0~1, where i is a positive integer, and 1≦i≦n. Taking 255 gray levels as an example, adopt "Formula 1" as follows:

Where i is a positive integer and 1≦i≦n.

In practice, the initial brightness value may be obtained by modulating the gray-scale signal in any manner, which is not limited to "Formula 1" here.

Next, in step 304, the background brightness calculation unit 132B of the signal processing unit 132 receives and calculates the initial brightness values of the first color DIB _1a to DIB _na and the second color of each pixel signal DI ₁ to DI _n according to “Formula 2” The initial brightness values DIB _1b ~DIB _nb and the third color initial brightness values DIB _1c ~DIB _nc to generate the corresponding first-color background brightness values KB _1a ~KB _na and the first for each pixel signal DI ₁ ~DI _n The two-color background brightness value KB _1b ~KB _nb and the third-color background brightness value KB _1c ~KB _nc . In other words, through this step 304, the first to third color initial brightness values of each pixel signal DI _i [DIB _ia , DIB _ib , DIB _ic ] are calculated to obtain the first value of each pixel signal DI _i To the third color background brightness value [KB _ia , KB _ib , KB _ic ]. Among them, "Formula 2" is as follows: KB _ia = DIB _ia -p*min( DIB _ib ,DIB _ic ); if KB _ia <0 ,KB _ia = DIB _ia

KB _ib = DIB _ib -p*min( DIB _ia ,DIB _ic ); if KB _ib <0 ,KB _ib = DIB _ib

KB _ic = DIB _ic -p*min( DIB _ia ,DIB _ib ); if KB _ic <0 ,KB _ic = DIB _ic

Where p is a constant. In some embodiments, p is 0.5.

Next, in step 306, according to "Formula 3", the screen brightness determination unit 132P of the signal processing unit 132 receives the color background brightness value and finds the maximum value of the first color background brightness value KB _1a ~ KB _na as the first color screen Brightness value KB _maxa ; find the maximum value of the second color background brightness value KB _1b ~ KB _nb , as the second color screen brightness value KB _maxb ; find the third color background brightness value KB _1c ~ KB _nc , as The brightness value of the third color picture KB _maxc . Among them, "Formula 3" is as follows: KB _maxa =max( KB _{1 a} : KB _na )

KB _maxb =max( KB _{1 b} : KB _nb )

KB _maxc =max( KB _{1 c} : KB _nc )

In step 308, it is determined whether to adopt the power saving mode according to the user's selection. If the power saving mode is to be adopted, go to step 310. If the power saving mode is not to be adopted, go directly to step 312.

In step 310, the screen brightness determination unit 132P of the signal processing unit 132 reduces the first-color screen brightness value KB _maxa , the second-color screen brightness value KB _maxb and the third-color screen brightness value KB _maxc according to the lookup table LUT. Specifically, the look-up table LUT has predicted brightness values KB _maxa ′, KB _maxb ′, and KB _maxc ′ corresponding to the allowable color difference values for each color difference, and when setting a certain color difference allowable value, that the first to third color screen brightness value _{KB maxa,} KB maxb _KB maxc and degree of reduction, and the first to third color screen brightness value _{KB maxa,} KB maxb _KB maxc and were adjusted to a first color is expected to The third-color screen brightness values KB _maxa ', KB _maxb ', and KB _maxc '. For example, refer to Table 1:

The above table 1 depends on the light source design type of each display device 100, which calculates the number of closed pixels and measures the corresponding signal value/brightness value. Among them, the color difference allowable value refers to the ratio of the number of closed pixels to the total number of pixels. It should be understood that the above Table 1 is only an example of the display device 100, and the scope of the present invention should not be limited by the above Table 1.

According to this, through steps 306 to 310, the color gamut of the backlight of each frame can be determined.

Next, in step 312, the backlight signal generating unit 134 receives the first to third color image brightness values KB _maxa , KB _maxb and KB _maxc (if reduced to the first to third color image brightness values KB _maxa if in power saving mode) ', KB _maxb 'and KB _maxc '), and according to the "Formula 4", with the first to third color screen brightness values KB _maxa , KB _maxb and KB _maxc (if the power saving mode is reduced to the first to third The minimum values of the color screen brightness values KB _maxa ', KB _maxb ', and KB _maxc ') determine a white backlight brightness signal BLB _w . In detail, since the first color to the third color are mixed and white light is formed, the smallest brightness value among the three colors can be taken as the white backlight brightness value. Among them "Formula 4" is as follows: BLB _w = MIN ( KB _maxa , KB _maxb , KB _maxc )

In step 314, according to "Formula 5," the backlight signal generating unit 134 amplifies the brightness values KB _maxa , KB _maxb, and KB _{maxc of the} first to third color images at an enlargement ratio (if the power saving mode is reduced to the first to The brightness values of the third-color screens KB _maxa ', KB _maxb ', and KB _maxc '), and the amplified first to third-color screen brightness values KB _maxa , KB _maxb, and KB _maxc (if reduced to The brightness values of the first to third colors KB _maxa ', KB _maxb 'and KB _maxc ') deduct the white backlight brightness signal BLB _w to obtain the first color backlight brightness signal BLB _a and the second color backlight brightness signal BLB _b 3. The third color backlight brightness signal BLB _c . Among them, "Formula 5" is as follows: BLB _a = a* KB _maxa - BLB _W

BLB _b =a＊ KB _maxb - BLB _W

BLB _c = a * KB _maxc - BLB _W where a is the magnification ratio. In some embodiments, a is approximately the reciprocal of the area ratio of the first to third dichroic pixels 122a-122c to the entire pixel 122. For example, the first to third dichroic pixels 122a-122c occupy a total area ratio of the pixel 122 is 0.75, and a can be designed to be between 1.3 and 1.5, such as 1.4.

In detail, here, first calculate the backlight intensity of the wide color gamut panel without reducing the brightness of the panel (in this embodiment, because of the pixel design relationship, it is 1.4 times the brightness value of the original color screen), and then With this backlight intensity minus the calculated white light backlight brightness value, the solid color backlight brightness value is obtained. At this point, the backlight signal group BLG is obtained, which includes the white backlight luminance signal BLB _w and the first to third color backlight luminance signals BLB _a , BLB _b , and BLB _c . The backlight signal group BLG can adjust the brightness of the pure color according to the input image signal SI received at the time sequence, to achieve the backlight effect of the color change (such as red, green, yellow, blue, etc.) of the time sequence change, thereby expanding the color gamut of the display device 100.

On the other hand, in step 316, the screen brightness determination unit 132P of the signal processing unit 132 uses the reciprocal of the first-color screen brightness value KB _maxa (decreased to the first-color screen brightness value KB _maxa 'in the power saving mode) as The first-color liquid crystal compensation value α _a , the _{reciprocal of the} second-color screen brightness value KB _maxb (if reduced to the second-color screen brightness value KB _maxb ′ in the power saving mode) is used as the second-color liquid crystal compensation value α _b , to The _{reciprocal of the} third-color screen brightness value KB _maxc (decreased to the third-color screen brightness value KB _maxc 'in the power saving mode) is used as the third-color liquid crystal compensation value α _c .

In steps 318 and 320, the sub-pixel signal generating unit 136 is used to generate a pixel signal for display. Here, in the process of converting the three-color pixel signal into the four-color pixel signal, the sub-pixel signal generating unit 136 corrects the pixel signal used for display with the liquid crystal compensation value to respond to the backlight signal group BLG’s The backlight brightness signal adjusts the pixel signal used for display.

Specifically, in step 318, the calculation unit 136C of the sub-pixel signal generation unit 136 first performs calculation according to "Formula 6". With the smallest of the first to third color liquid crystal compensation values α _a ~α _c and the first color initial brightness value DIB _1a ~DIB _na and the second color initial brightness value DIB of each pixel signal DI ₁ ~DI _{n 1b} ~ DIB _nb and the minimum value of the third color initial brightness value DIB _1c ~ DIB _nc are multiplied and multiplied by a certain ratio to generate the white sub-pixel brightness value DOB _{1w of} each pixel signal DI ₁ ~ DI _n ~DOB _nw . Among them, "Formula 6" is as follows:

Among them 0.5≦q≦0.75.

Next, in step 320, the calculation unit 136C of the sub-pixel signal generation unit 136 performs calculation according to "Formula 7". Multiply the first to third color LCD compensation values by the first to third color initial brightness values DIB _1a to DIB _na , DIB _1b to DIB _nb, and DIB _1c to DIB _{nc of} each pixel signal DI ₁ to DI _n α _a ~α _c , and then subtract the _weights of the first to third colors in the white sub-pixel brightness values DOB _1w ~DOB _nw (here, the first to third color liquid crystal compensation values α _a ~α _c Multiply by DOB _1w ~DOB _nw and then multiply by 0.5), and then generate the first color subpixel brightness value DOB _1a ~DOB _na , the second color subpixel brightness value DOB _1b ~DOB _nb and the third color subpixel brightness Values DOB _1c ~DOB _nc . In other words, the initial brightness values of the first to third colors [DIB _ia , DIB _ib , DIB _ic ] of each pixel signal DI _i are converted to the brightness values of the first to third color sub-pixels by calculation [DOB _ia , DOB _ib , DOB _ic ]. Among them, "Formula 7" is as follows: DOB _ia =α _a * DIB _ia -α _a *0.5*min( DIB _ia ,DIB _ib ,DIB _ic )

DOB _ib =α _b ＊ DIB _ib -α _b ＊0.5＊min( DIB _ia ,DIB _ib ,DIB _ic )

DOB _ic =α _c ＊ DIB _ic -α _c ＊0.5＊min( DIB _ia ,DIB _ib ,DIB _ic )

In detail, here, according to the brightness signal of the backlight, the initial brightness value of the pixel is adjusted correspondingly, and then the portion provided by the white brightness value is deducted from the adjusted initial brightness value, the pure color of the wide color gamut panel can be obtained Brightness value.

In step 322, an inverse gray-scale conversion unit 136G of the sub-pixel signal generating unit 136 performs an inverse gray-scale conversion to convert the white sub-pixel brightness values DOB _1w to DOB _nw and the first to third color sub-pixel brightness The values DOB _1a ~DOB _na , DOB _1b ~DOB _nb and DOB _1c ~DOB _{nc are} converted into white subpixel grayscale signals DOG _1w ~DOG _nw and the first to third subpixel grayscale signals DOG _1a ~DOG _na , DOG _1b ~DOG _nb and DOG _1c ~DOG _nc . In other words, the first to third colors of each pixel signal DI _i and the brightness value of the white sub-pixels [DOB _ia , DOB _ib , DOB _ic , DOB _iw ] are calculated and converted into the first to third colors and White sub-pixel grayscale signals [DOG _ia , DOG _ib , DOG _ic , DOG _iw ].

Here, the sub-pixel signal generating unit 136 is used to determine the initial brightness values of the first to third colors DIB _1a to DIB _na and DIB _1b of the first to third colors of the input image signal SI (different pixel signals DI ₁ to DI _n derived) DIB _nb and DIB _1c ~DIB _nc ) and the first-color screen brightness value KB _maxa , the second-color screen brightness value KB _maxb and the third-color screen brightness value KB _maxc (the first to third-color liquid crystal compensation value α _a ~ reciprocal of α _c ) to generate the sub-pixel signal group DPG. The sub-pixel signal group DPG includes white sub-pixel gray-scale signals DOG _1w ~ DOG _nw and first to third sub-pixel gray-scale signals DOG _1a ~ DOG _na , DOG _1b ~ DOG _nb and DOG _1c ~ DOG _nc .

In step 324, the backlight control unit 150 controls the first to the third of the backlight module 110 according to the white backlight luminance signal BLB _{w of the} backlight signal group BLG and the first to third color backlight luminance signals BLB _a , BLB _b , and BLB _c , respectively. Four-color light sources 112a~112d.

The liquid crystal control unit 160 is based on the white sub-pixel gray scale signals DOG _1w ~ DOG _{nw of the} sub-pixel signal group DPG and the first to third sub-pixel gray scale signals DOG _1a ~ DOG _na , DOG _1b ~ DOG _nb and DOG _1c ~ DOG _nc , respectively control the first to fourth dichroic pixels 122a ~ 122d of the liquid crystal cell 120. Here, the first to fourth dichroic pixels 122a to 122d each occupy a quarter of the overall pixel area, of course, this should not be used to limit the scope of the invention, and in other embodiments, other configurations are possible , And then adjust the parameter a of the aforementioned "Formula 5".

In some embodiments of the present invention, as described above, the backlight signal group BLG can adjust the brightness of the pure color according to the input image signal SI received at the time sequence to achieve the color-shifted backlight effect of the time sequence change, thereby expanding the color gamut of the display device 100. Furthermore, in view of the fact that the generation of the backlight signal group BLG and the sub-pixel signal group DPG are all related to the first to third color picture brightness values KB _maxa , KB _maxb and KB _maxc (the first to third color liquid crystal compensation values α ₍ Reciprocal of _a ~ α _c ) is related, the sub-pixel signal group DPG is also adjusted with the backlight signal group BLG. So far, the image quality of the panel and the best power saving performance can be improved.

In some embodiments of the invention, the first to third colors in the above display method are exemplified by red, green, and blue. The following describes in detail the embodiment when the above display method is applied to a red, green and blue (RGB) signal.

Here, an embodiment in which the power saving mode is not used is introduced first. In the following embodiments, the input image signal SI includes pixel signals DI ₁ to DI ₄ as an example, that is, n=4.

First, the RGB initial grayscale signals (DIG _1a , DIG _1b , DIG _1c ) of the pixel signal DI ₁ in the input image signal SI are (255,0,0), and the RGB initial gray scale signals of the pixel signal DI ₂ ( _{DIG 2a, DIG 2b, DIG 2c} ) is (255,255,255), the original gray scale pixel signal DI RGB signal _{3 (DIG 3a, DIG 3b, DIG} 3c) to (0,250,0), the original pixel signal DI RGB ₄ The grayscale signals (DIG _4a , DIG _4b , DIG _4c ) are (0, 0, 224).

In step 302, the RGB initial gray-scale signals of the pixel signals DI ₁ to DI ₄ are gamma-converted into RGB initial brightness values according to “Formula 1”. In this example, the signal DI RGB pixel value initial luminance _{1 [DIB 1a, DIB 1b, DIB} 1c] is [1,0,0], DI RGB pixel signal value of the initial _luminance of [DIB _2a, DIB _2b , DIB _2c ] is [1,1,1], the initial RGB brightness value of pixel signal DI ₃ [DIB _3a , DIB _3b , DIB _3c ] is [0,0.96,0], RGB of pixel signal DI ₄ The initial brightness values [DIB _4a , DIB _4b , DIB _4c ] are [0, 0, 0.75].

Next, in step 304, according to "Formula 2," the RGB background brightness value of the pixel signal DI ₁ [KB _1a , KB _1b , KB _1c ] is [1,0,0], and the RGB of the pixel signal DI ₂ The background brightness value [KB _2a , KB _2b , KB _2c ] is [0.5,0.5,0.5], and the RGB background brightness value of the pixel signal DI ₃ [KB _3a ,KB _3b ,KB _3c ] is [0,0.96,0] , The RGB background brightness value [KB _4a , KB _4b , KB _4c ] of pixel signal DI ₄ is [0,0,0.75].

Next, in step 306, according to "Formula 3", the brightness values of the first to third colors of the pixel signals DI ₁ to DI ₄ [KB _maxa , KB _maxb , KB _maxc ] are [ 1,0.96,0.75].

In step 308, it is decided not to adopt the power saving mode, and directly go to step 312. In step 312, according to "Formula 4," the white backlight brightness signal BLB _w is 0.75.

In step 314, according to "Formula 5," assuming that a is 1.4, the first to third color backlight luminance signals BLB _a , BLB _b , and BLB _c are 0.65, 0.59, and 0.3. At this point, the backlight signal group BLG is obtained.

In step 316, the RGB liquid crystal compensation values α _a , α _b , and α _c are obtained as 1, 1.04, and 1.33, respectively.

In step 318, according to "Formula 6," assuming that q is equal to 0.5, the brightness value DOB _1w of the white sub-pixel of the pixel signal DI ₁ is 0, and the brightness value DOB _2w of the white sub-pixel of the pixel signal DI ₂ is 0.5, the white sub-pixel pixel signal DI ₃ DOB _3w luminance value is 0, the pixel signal DI white sub-pixel luminance value of 0 DOB ₄ is _4w.

In step 320, according to "Formula 7," the sub-pixel brightness values of the pixel signal DI ₁ [DOB _1a , DOB _1b , DOB _1c , DOB _1w ] are [1,0,0,0], the pixel signal The subpixel brightness values of DI ₂ [DOB _2a , DOB _2b , DOB _2c , DOB _2w ] are [0.5, 0.52, 0.67, 0.5], and the subpixel brightness values of the pixel signal DI ₃ [DOB _3a , DOB _3b , DOB _3c , DOB _3w ] is [0,1,0,0], the sub-pixel brightness value of pixel signal DI ₄ [DOB _4a , DOB _4b , DOB _4c , DOB _4w ] is [0,0,1,0 ].

In step 322, an inverse grayscale conversion is performed to obtain the subpixel grayscale signals (DOG _1a , DOG _1b , DOG _1c , DOG _1w ) of the pixel signal DI ₁ as (255,0,0,0), the pixel signal DI subpixel gray signal _{(DOG 2a, DOG 2b, DOG} 2c, DOG 2w) 2 is (186,189,213,186), the sub-pixel gray scale pixel signal DI signal ₃ (DOG _3a, DOG _3b, DOG _3c , DOG _3w ) is (0,255,0,0), and the sub-pixel grayscale signals (DOG _4a , DOG _4b , DOG _4c , DOG _4w ) of the pixel signal DI ₄ are (0,0,255,0). At this point, the sub-pixel signal group DPG is obtained.

So far, the backlight module 110 and the liquid crystal control unit 160 can be controlled in step 324.

Hereinafter, another embodiment adopting the power saving mode will be described.

For convenience of description, following step 306 in the previous example, and adopting the power saving mode in step 308, proceed to step 310.

In step 310, according to "Formula 4," if the power saving mode with a color difference tolerance of 1% is adopted, the original RGB color screen brightness values KB _maxa , KB _maxb , KB _maxc [1,0.95,0.75] can be adjusted to RGB color screen brightness values KB _maxa ', KB _maxb ', KB _maxc '[0.99, 0.67, 0.58].

In step 312, according to "Formula 4," the white backlight luminance signal BLB _w is 0.58.

In step 314, according to "Formula 5," assuming that a is 1.4, the first to third color backlight luminance signals BLB _a , BLB _b , and BLB _c are 0.80, 0.36, and 0.23.

In step 316, the RGB liquid crystal compensation values α _a , α _b , and α _c are 1.01, 1.49, and 1.73, respectively. At this point, the backlight signal group BLG is obtained.

In step 318, according to "Formula 6," assuming that q is equal to 0.5, the brightness value DOB _2w of the white sub-pixel of the pixel signal DI ₂ is 0.505.

In step 320, according to "Formula 7," the sub-pixel brightness values [DOB _2a , DOB _2b , DOB _2c , DOB _2w ] of the pixel signal DI ₂ are [0.505, 0.74, 0.87, 0.505].

In step 322, an inverse gray-scale conversion is performed, and the sub-pixel gray-scale signals (DOG _2a , DOG _2b , DOG _2c , DOG _2w ) of the pixel signal DI ₂ are (186, 189, 213, 186).

So far, the backlight module 110 and the liquid crystal control unit 160 can be controlled in step 324.

4A to 4C are schematic top views of pixels 122 in some embodiments of the invention. In the foregoing embodiment, the first to fourth dichroic pixels 122a to 122d of the pixel 122 are sequentially arranged in the horizontal direction. However, it should be understood that the first to fourth dichroic pixels 122a to 122d of the pixel 122 may have various arrangements.

In FIG. 4A, each pixel 122 includes 16 long sub-pixels. In FIG. 4B, each pixel 122 includes 16 square sub-pixels. In FIG. 4C, each pixel 122 includes 8 long sub-pixels. In these figures, the above parameters (eg, q, r) are designed based on the same area of each color sub-pixel, but it should be understood that this should not limit the scope of the present invention. In other embodiments, the area of each color sub-pixel can be different, and the above parameters should also be adjusted accordingly. In addition, although the first to fourth color sub-pixels 122a-122d are respectively represented by RGBW, it should be understood that the scope of the present invention should not be limited by any color or number of pixels.

In various embodiments of the present invention, the input three-color signal is converted to a four-color signal, so that the image quality can be achieved in a wide color gamut (such as RGBW) LCD display and even better than a solid color (such as RGB) LCD display. effect. The signal conversion process is combined with digital dynamic backlight operation, so that a wide color gamut (such as RGBW) LCD signal can be matched with a multi-primary color backlight signal. In addition to improving the problem of darker solid colors and brighter white images, the color gamut is improved. It can achieve a more power-saving effect than ordinary solid color (such as RGB) liquid crystal displays, and can take into account the requirements for image quality and power saving.

Although the present invention has been disclosed in various embodiments as above, it is not intended to limit the present invention. Anyone who is familiar with this skill can make various changes and modifications without departing from the spirit and scope of the present invention. The scope of protection shall be deemed as defined by the scope of the attached patent application.

100‧‧‧Display device

110‧‧‧Backlight module

120‧‧‧LCD unit

122‧‧‧ pixels

130‧‧‧ processor

132‧‧‧ Gray scale processing unit

132G‧‧‧Gray scale conversion unit

132B‧‧‧Background brightness calculation unit

132P‧‧‧Picture brightness determination unit

134‧‧‧Backlight signal generation unit

136‧‧‧ Sub-pixel signal generation unit

136C‧‧‧Calculation unit

136G‧‧‧Inverse Grayscale Conversion Unit

140‧‧‧register

150‧‧‧Backlight control unit

160‧‧‧LCD control unit

LUT‧‧‧Lookup Table

SI‧‧‧ Input video signal

DIG _ia ‧‧‧ first color grayscale signal

DIG _ib ‧‧‧Second color initial grayscale signal

DIG _ic ‧‧‧ third color initial grayscale signal

DIB _ia ‧‧‧ initial brightness value of the first color

DIB _ib ‧‧‧ initial brightness value of the second color

DIB _ic ‧‧‧The initial brightness value of the third color

KB _ia ‧‧‧ First color background brightness value

KB _ib ‧‧‧ Second color background brightness value

KB _ic ‧‧‧The brightness value of the third color background

KB _maxa ‧‧‧ First-color screen brightness value

KB _maxb ‧‧‧ Second-color screen brightness value

KB _maxc ‧‧‧ Brightness value of the third color screen

BLB _w ‧‧‧White backlight brightness signal

BLB _a ‧‧‧ First color backlight brightness signal

BLB _b ‧‧‧ Second color backlight brightness signal

BLB _c ‧‧‧ third color backlight brightness signal

α _a ‧‧‧ First color LCD compensation value

α _b ‧‧‧ Compensation value of the second color LCD

α _c ‧‧‧ Compensation value of the third color LCD

DOB _iw ‧‧‧ White sub-pixel brightness value

DOB _ia ‧‧‧ brightness value of the first dice pixel

DOB _ib ‧‧‧ brightness value of the second color pixel

DOB _ic ‧‧‧ Brightness value of the third color pixel

DOG _iw ‧‧‧White sub-pixel grayscale signal

DOG _ia ‧‧‧ First dice pixel grayscale signal

DOG _ib ‧‧‧ Second color pixel grayscale signal

DOG _ic ‧‧‧ third color pixel grayscale signal

DPG‧‧‧Sub-pixel signal group

BLG‧‧‧Backlight signal group

Claims (18)

A display method of a display device includes: receiving an input image signal, wherein the input image signal includes a plurality of pixel signals; calculating an initial brightness value of a first color and an initial brightness of a second color for each of the pixel signals Value and a third color initial brightness value to determine a first color picture brightness value, a second color picture brightness value and a third color picture brightness value; calculate the first color picture brightness value and the second color picture The brightness value and the brightness value of the third-color image to generate a backlight signal group; calculating the brightness value of the first-color image, the brightness value of the second-color image, the brightness value of the third-color image, and each of the pixel signals The initial luminance value of the first color, the initial luminance value of the second color, and the initial luminance value of the third color to generate a sub-pixel signal group for each of the pixel signals; the backlight signal group controls a A first color light source, a second color light source, a third color light source and a fourth color light source of the backlight module; and a first color sub-pixel of a liquid crystal cell controlled by the sub-pixel signal group, A second color sub-pixel, a third color sub-pixel and a fourth color sub-pixel. The display method of the display device according to claim 1, wherein the process of determining the luminance value of the first color picture, the luminance value of the second color picture and the luminance value of the third color picture comprises: calculating each of the pixels The first color initial brightness value of the signal, the second color initial brightness value and the third color initial brightness value to generate a first color background brightness value and a second color background brightness value for each of the pixel signals Value and a third-color background brightness value; and the largest of the first-color background brightness values of the pixel signals, the largest of the second-color background brightness values, and the third colors The largest of the background brightness values is respectively the brightness value of the first color screen, the brightness value of the second color screen, and the brightness value of the third color screen. The display method of the display device according to claim 1, further comprising: before generating the backlight signal group, reducing the brightness value of the first color frame, the brightness value of the second color frame, and the brightness value of the third color frame. The display method of the display device according to claim 3, further comprising: adjusting the reduction levels of the first-color screen brightness value, the second-color screen brightness value, and the third-color screen brightness value according to a color difference tolerance value. The display method of the display device according to claim 1, wherein the process of generating the backlight signal group includes: using the minimum of the brightness value of the first color picture, the brightness value of the second color picture and the brightness value of the third color picture As a fourth color backlight brightness signal of the backlight signal group; the first color picture brightness value, the second color picture brightness value and the third color picture brightness value are amplified; and the first color picture is amplified by the The brightness value, the brightness value of the amplified second-color picture and the brightness value of the amplified third-color picture minus the fourth-color backlight brightness signal to obtain a first-color backlight brightness signal and a first color of the backlight signal group, respectively Two-color backlight brightness signal and a third-color backlight brightness signal. The display method of the display device according to claim 5, wherein the brightness value of the first-color picture, the brightness value of the second-color picture, and the brightness value of the third-color picture are enlarged at the same scale. The display method of the display device according to claim 5, wherein the fourth color backlight brightness signal is a white light backlight signal. The display method of the display device according to claim 1, wherein the sub-pixel signal group includes a first color sub-pixel gray scale signal, a second color sub-pixel gray scale signal, and a third color sub-pixel The gray scale signal and a fourth dice pixel gray scale signal. The display method of the display device according to claim 8, wherein the generation process of the sub-pixel signal group includes: using the luminance value of the first color picture, the luminance value of the second color picture and the luminance value of the third color picture Reciprocal, obtain a first liquid crystal compensation value, a second liquid crystal compensation value and a third color liquid crystal compensation value; calculate the first color initial brightness value of the pixel signals, the second color initial brightness value and the The smallest of the initial brightness values of the third color and the smallest of the first liquid crystal compensation value, the second liquid crystal compensation value, and the third color liquid crystal compensation value to generate a fourth color subpixel brightness value; and calculation The first color initial brightness value, the second color initial brightness value, the third color initial brightness value, the first color liquid crystal compensation value, the second color liquid crystal compensation value, the third color liquid crystal compensation value, and the first The four-color sub-pixel brightness value is used to generate a first color sub-pixel brightness value, a second color sub-pixel brightness value, and a third color sub-pixel brightness value. The display method of the display device according to claim 9, wherein the generation process of the sub-pixel signal group further includes: the luminance value of the first sub-pixel, the luminance value of the second sub-pixel, the third Dimming pixel luminance value and the fourth dichroic pixel luminance value, performing an inverse grayscale conversion to obtain the first dichroic pixel grayscale signal, the second dichroic pixel grayscale signal, the first The three-color pixel gray-scale signal and the fourth color pixel gray-scale signal. The display method of the display device according to claim 8, wherein the grayscale signal of the fourth sub-pixel is a white sub-pixel signal. The display method of the display device according to claim 1, wherein each of the pixel signals includes a first-color initial grayscale signal, a second-color initial grayscale signal, and a third-color initial grayscale signal, the The method includes: performing a grayscale conversion to convert the first color initial grayscale signal, the second color initial grayscale signal and the third color initial grayscale signal of each of the pixel signals into each The initial luminance value of the first color, the initial luminance value of the second color, and the initial luminance value of the third color of the pixel signals. A display device includes: a backlight module including a first color light source, a second color light source, a third color light source and a fourth color light source; a liquid crystal unit for displaying an output image, wherein the liquid crystal The unit includes a plurality of pixels, and each of the pixels includes a first dichroic pixel, a second dichroic pixel, a third dichroic pixel, and a fourth dichroic pixel; a signal processing unit , Used to determine a first-color image brightness value, a second-color image brightness value, and a third-color image brightness value according to a plurality of pixel signals of an input image signal; a backlight signal generation unit is used to calculate the A first-color image brightness value, a second-color image brightness value and a third-color image brightness value to generate a backlight signal group; a sub-pixel signal generation unit for generating the backlight image signal and the first-color image according to the input image signal The brightness value, the brightness value of the second color picture and the brightness value of the third color picture generate a sub-pixel signal group; a backlight control unit for controlling the backlight module according to the backlight signal group; and a liquid crystal control unit To control the liquid crystal cell according to the sub-pixel signal group. The display device according to claim 13, wherein the signal processing unit includes: a background brightness calculation unit for receiving and processing the pixel signals of the input image signal, according to one of each of the pixel signals The first color initial brightness value, a second color initial brightness value, and a third color initial brightness value generate a first color background brightness value, a second color background brightness value, and a first color for each of the pixel signals Three-color background brightness value; and a picture brightness determination unit for taking out the largest of the first-color background brightness values of the pixel signals and the second-color background brightness values of the pixel signals And the largest of the third-color background luminance values of the pixel signals is used as the first-color image luminance value, the second-color image luminance value, and the third-color image luminance value, respectively. The display device according to claim 14, wherein the sub-pixel signal generation unit is based on the first-color image brightness value, the second-color image brightness value, the third-color image brightness, and each of the pixel signals The initial luminance value of the first color, the initial luminance value of the second color, and the initial luminance value of the third color generate the sub-pixel signal group. The display device according to claim 14, wherein the picture brightness determination unit is further used for performing the following steps: reducing the brightness value of the first color picture, the brightness value of the second color picture, and the brightness value of the third color picture. The display device according to claim 13, wherein the fourth color light source is a white light source. The display device according to claim 13, wherein the fourth color sub-pixel is a white sub-pixel.

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