TWI479472B - A method for reducing the color separation of a liquid crystal display - Google Patents

Description

Display method for reducing color separation of liquid crystal display

The present invention relates to a display method for reducing color separation of a liquid crystal display, and more particularly to a display method for reducing color separation applied to a liquid crystal display.

In recent years, with the gradual development of the flat panel display industry, display technology has also been continuously updated, and liquid crystal displays (LCDs) that are small in size, light in weight, and have low electromagnetic radiation have become mainstream products of displays.

However, in the past, liquid crystal displays using spatial color filter (SCF) technology, each pixel in the liquid crystal module is composed of three sub-pixels, and each sub-pixel is separately composed of one A Field Effect Transistor (TFT) controls the electric field strength. Because each pixel requires at least three field-effect transistors and color filters, it not only consumes raw material costs, but also increases the complexity of manufacturing liquid crystal displays and greatly reduces light efficiency. Therefore, the field Sequential Color (FSC) display technology has been developed in the industry, and the light source of the three primary colors is switched in time series, and the transmittance of the liquid crystal pixels is synchronously controlled to adjust the relative light intensity of each color light source. The integral effect of the visual system on the light stimulus is then used to form the color to be displayed.

The field color sequential display technology can achieve color display without using color filters, and each pixel does not need to be divided into sub-pixels, and the field effect transistor required in a single pixel can be reduced, thereby saving raw materials. Costs can simplify process procedures. Under ideal imaging conditions, the three primary colors contained in a single color image should be projected to the corresponding position of each pixel on the retina of the human eye, and the color information of each pixel can be completely reproduced visually, but if it is a color image. The three primary color image colors included In the field, the corresponding pixels are projected onto different positions on the retina and then detected by the visual system. The observer will see the picture of the color field being separated from the misalignment. This is called the color separation phenomenon. Since the color separation phenomenon greatly degrades the display quality, the color separation phenomenon is an important problem that the field color sequential display technology must be improved.

At present, a monochrome image can be used to solve the phenomenon of color separation. For example, the red light emitting diode, the green light emitting diode, and the blue light emitting diode are used as backlights as disclosed in U.S. Patent No. 7,057,668. When the image signal is input, the input image signal is converted into a YCrCb color system. When the color separation phenomenon of the display content is slight, the field color sequence display technology is used to display the picture, but if the color separation phenomenon of the display content is serious, another monochrome picture is inserted, and the red light emitting diode is simultaneously turned on. The green light-emitting diode and the blue light-emitting diode make the backlight change to display the full-bright white light, so that the colored stripes generated by the color separation phenomenon are mixed with the inserted monochrome image, thereby reducing the color separation phenomenon by the visual system. The opportunity to know.

Although the above method can solve the phenomenon of partial color separation, when the liquid crystal display of the field color sequential display technology is viewed in the forward direction, since the liquid crystal still has light leakage in the positive direction, thereby reducing the contrast of the liquid crystal display, How to effectively solve the color separation phenomenon, but also improve the contrast of the liquid crystal display is currently the main research and development direction.

The invention provides a display method for reducing color separation of a liquid crystal display. By combining high dynamic contrast display technology and field color sequential display technology, the phenomenon of color separation of the liquid crystal display is reduced, and the liquid crystal display can simultaneously have high contrast and low Power consumption, high color saturation, low manufacturing cost, etc.

To achieve the above objective, the present invention provides a display method for reducing color separation of a liquid crystal display, comprising the steps of: generating a control signal for each sub-picture, the control signal comprising a plurality of second backlight control signals and a plurality of second liquid crystals The method of controlling the signal and generating the control signal includes the following steps: analyzing an input The image signal is used to obtain a first liquid crystal control signal and a first backlight control signal for each color of each pixel; the divided sub-picture is a plurality of display areas; and the second color of each color in each display area is generated. a backlight control signal generated by the first liquid crystal control signals; generating a second liquid crystal control signal for each color of each pixel in each display area, which is generated according to the second backlight control signal; Generating a third liquid crystal control signal for each display area; and sequentially displaying the sub-pictures, including the steps of: displaying a colorful sub-picture, which is simultaneously controlled according to a second backlight of each color light in each display area The signal is matched with the third liquid crystal control signal display; and each color photon picture is sequentially displayed, and each color photon picture is matched with the second liquid crystal control signal of each pixel according to the second backlight control signal of the color light in each display area. The result of the operation with one of the third liquid crystal control signals is displayed.

To achieve the above object, the present invention further provides a display method for reducing color separation of a liquid crystal display, comprising the steps of: generating a control signal for each sub-picture, the control signal comprising a plurality of second backlight control signals and a plurality of second The liquid crystal control signal and the method for generating the control signal include the following steps: analyzing an input image signal to obtain a first liquid crystal control signal and a first backlight control signal for each color of each pixel; dividing the sub-picture a plurality of display areas; generating a second backlight control signal for each color light in each display area, which is generated by the first liquid crystal control signals; generating each color of each display area for each pixel a second liquid crystal control signal generated according to the second backlight control signal; and generating a third liquid crystal control signal for each display area; and sequentially displaying the sub-pictures, the method comprising the steps of: displaying a colorful sub-picture Selecting a first color light and a second color light from the color lights, and controlling the second color and the second color by the second color light of the first color light The second backlight control signal is displayed in conjunction with the third liquid crystal control signal; displaying a first color photon image, which is matched with the second color light of the first color light to match the first color light to the second liquid crystal of each pixel Displaying a result of the operation of one of the control signal and the third liquid crystal control signal; displaying a second color photon image, wherein the second backlight control signal of the second color light is matched with the second liquid crystal control signal of the second color light for each pixel Displaying the result of the operation with the third liquid crystal control signal; and displaying a third color The photon picture is displayed according to a second backlight control signal of a third color light and a third color light is displayed on the second liquid crystal control signal of each pixel.

With the implementation of the present invention, at least the following advancements can be achieved:

1. By reducing the contribution of each color photon picture to the displayed picture, the generation of color separation can be reduced.

Second, adjust the size of the backlight signal in different display areas in each sub-picture, thereby improving the contrast of the liquid crystal display and reducing power consumption.

In order to make those skilled in the art understand the technical content of the present invention and implement it, and according to the disclosure, the patent scope and the drawings, the related objects and advantages of the present invention can be easily understood by those skilled in the art. The detailed features and advantages of the present invention will be described in detail in the embodiments.

S100‧‧‧Reducing the display method of color separation of liquid crystal display

S110‧‧‧ generates control signals for each sub-picture

S111‧‧‧Analysis of input image signals

S112‧‧‧Separated sub-pictures are multiple display areas

S113‧‧‧ generating a second backlight control signal for each color of light in each display area

S114‧‧‧ generating a second liquid crystal control signal for each color of light in each display area

S115‧‧‧ generates a third liquid crystal control signal for each display area

S120, S120'‧‧‧Sequence display sub-screen

S121, S121'‧‧‧ display colorful sprites

S122‧‧‧ Display each color photon screen in sequence

S123‧‧‧Displays the first color photon screen

S124‧‧‧Display second color photon screen

S125‧‧‧Displays the third color photon screen

12‧‧‧First LCD Control Signal

11‧‧‧First backlight control signal

21‧‧‧Second backlight control signal

22‧‧‧Second LCD control signal

23‧‧‧ Third LCD Control Signal

24‧‧‧Operation results

FIG. 1 is a view showing a flow chart of a method for reducing color separation display of a liquid crystal display according to the present invention.

FIG. 2 is a diagram showing an embodiment of a process for generating a control signal for each sub-picture according to the present invention.

Figure 3 is a diagram of an embodiment of a color image to be displayed.

FIG. 4A is a first embodiment of a flow chart for displaying each sub-picture according to the present invention.

FIG. 4B is a first timing diagram showing an embodiment of each sub-picture according to the present invention.

Figure 5A is a flow chart 2 showing each sub-picture of the present invention.

FIG. 5B is a timing diagram 2 for displaying each sub-picture according to the present invention.

Fig. 6A is a flow chart showing the generation of a control signal in a display area in Fig. 3.

Figure 6B is a flow chart showing the sub-pictures sequentially displayed according to the control signals generated in Figure 6A.

1 is a diagram of reducing color separation display of a liquid crystal display according to the present invention A schematic diagram of a process embodiment of method S100. FIG. 2 is a schematic diagram of a flow of a control signal S110 for generating each sub-picture according to the present invention. Figure 3 is a diagram of an embodiment of a color image to be displayed. FIG. 4A is a first embodiment of a flow chart for displaying each sub-picture S120 according to the present invention. FIG. 4B is a first timing diagram showing an embodiment of each sub-picture S120 of the present invention. Fig. 5A is a flow chart 2 showing the display of each sub-picture S120' according to the present invention. Fig. 5B is a timing chart 2 showing the display of each sub-picture S120' according to the present invention. Fig. 6A is a flow chart showing the generation of a control signal in a display area in Fig. 3. Figure 6B is a flow chart showing the sub-pictures sequentially displayed according to the control signals generated in Figure 6A.

As shown in FIG. 1, the embodiment is a display method S100 for reducing color separation of a liquid crystal display, which comprises the steps of: generating a control signal S110 for each sub-picture; and sequentially displaying the sub-picture S120.

The control signal of each sub-picture includes a plurality of second backlight control signals, a plurality of second liquid crystal control signals and a third liquid crystal control signal, the second backlight control signal is used to control the backlight brightness of the backlight module, and the second The liquid crystal control signal is used to control the transmittance of the liquid crystal. The larger the second liquid crystal control signal, the higher the transmittance of the liquid crystal, that is, the brighter the brightness of the picture. In this embodiment, the backlight brightness is grayed out. The step value and the liquid crystal gray scale value indicate the size of the second backlight control signal and the second liquid crystal control signal.

As shown in FIG. 2, the method for generating the control signal S110 of each sub-picture includes the following steps: analyzing the input image signal S111; dividing the sub-picture into a plurality of display areas S112; generating the first color of each color in each display area a backlight control signal S113; generating a second liquid crystal control signal S114 for each color in each display area; and generating a third liquid crystal control signal S115 for each display area.

The input image signal S111 is analyzed; as shown in FIG. 3, if the color image to be displayed is shown in FIG. 3, the input image signal includes information such as a first backlight control signal and a first liquid crystal control signal, for example, if the backlight The brightness is fully bright, that is, the first backlight control signal is the maximum value of the backlight brightness grayscale value, for example Said, if the 8-bit control signal is used, the first backlight control signal is 255.

In the case that the backlight is fully lit, the liquid crystal display needs to control the transmittance of the liquid crystal in each pixel by the first liquid crystal control signal, so that the color of the display is divided into light and dark, so that the input image signal can be analyzed. And obtaining the first liquid crystal control signal and the first backlight control signal of each color in each pixel separately.

The divided sub-picture is a plurality of display areas S112; since some of the color images may be brighter and some of the pictures are darker, the sub-picture may be divided into a plurality of display areas, according to the brightness of each display area. The degree of backlight brightness of each display area is controlled separately. For example, as shown in FIG. 3, the sub-picture can be divided into 4×4 display areas.

a second backlight control signal S113 is generated for each color in each display area; in each display area, a value is generated from the first liquid crystal control signal of each color light as a second backlight control signal, and the user can The demand selection may be, for example, selecting the maximum value, the average value of the first liquid crystal control signal, or dividing the average value of the first liquid crystal control signal by the total order value of the first liquid crystal control signal, and opening the root of the first liquid crystal control signal , normalize it, and multiply by the total order value as the second backlight control signal.

For example, if the maximum value of the first liquid crystal control signal in the display area is selected as the second backlight control signal, for example, the maximum value of the first liquid crystal control signal in the display area is 95, the second backlight control signal is also 95. Since the pixel having the maximum value of the first liquid crystal control signal also represents the brightest pixel in the display area, if the brightness of the backlight can be directly adjusted to the brightest brightness in the display area, the backlight module can be reduced. The power consumed.

That is, by adjusting the backlight of each display area, using a weaker backlight directly in the originally darker display area, or even turning off the backlight of the display area, using a brighter backlight in the brighter display area, and Then, the transmittance of the liquid crystal is changed by the first liquid crystal control signal to achieve the color image to be displayed, thereby achieving the goal of low power consumption and improved picture contrast.

Generating a second liquid crystal control signal S114 for each color in each display area; since the color image displayed last is equal to the intensity of the color image generated according to the input image signal, it can be based on the known The second backlight control signal generates a second liquid crystal control signal, and the second liquid crystal control signal can be calculated according to the following equation: GL _HDR = GL _Full × (BL _Full / BL _HDR ) ^{1 / r} --- (1)

Wherein GL _HDR is the second liquid crystal control signal, BL _Full is the first backlight control signal, BL _HDR is the second backlight control signal, r is a gamma factor, and GL _Full is the first liquid crystal control signal. In addition, since the backlight sources of each display area may affect each other, the BL _Full in the equation (1) may be changed to the light intensity value of the first backlight control signal, and the BL _{HDR is} changed to the second backlight control signal. The light intensity value, thereby obtaining a more accurate and appropriate second liquid crystal control signal.

Generating a third liquid crystal control signal S115 for each display area; the third liquid crystal control signal is generated by all the second liquid crystal control signals of each color light, and the third liquid crystal control signal may be less than or equal to all the first of each color light The minimum value in the two LCD control signals.

As shown in FIG. 4A, the sub-picture S120 is sequentially displayed, including the steps of: displaying the colorful sub-picture S121; and sequentially displaying each color photo sub-picture S122.

Displaying a colorful sub-picture S121; as shown in FIG. 4B, the colorful sub-picture is formed by simultaneously displaying each color photon picture, and simultaneously matching the third liquid crystal according to the second backlight control signal of each color light in each display area. The control signal is displayed. The colorful sub-picture can be a picture composed of three colors of red light, green light and blue light, and the backlight brightness of each color light is separately controlled by the second backlight control signal of each color light, and matched with the third liquid crystal control signal. Control the transmittance of the liquid crystal.

Each color photon picture S122 is sequentially displayed; each color photon picture is based on a second backlight control signal of the color light in each display area, and one of the second liquid crystal control signal and the third liquid crystal control signal of each pixel is used. The calculation result may be the difference between the second liquid crystal control signal and the third liquid crystal control signal, but the method for generating the operation result is not limited thereto, and the user can adjust the picture quality according to the desired display.

As shown in FIG. 4B, each color image can complete a colorful sub-picture and a display of each color photon picture in a time period T, so that a complete color image can be formed by the visual effect of the human eye. A color image can display a complete color image by the visual effect of the human eye by displaying a colorful sub-picture and each color photon picture in a time period T, and the display of the colorful sub-picture can be, for example, FIG. 4B. As shown in the figure, a red photon picture, a green photon picture, and a blue photon picture are simultaneously displayed, and the second backlight control signal and the second liquid crystal control signal of each color photon picture are matched as described above.

In addition, the colorful sub-picture of the embodiment may display only two of the three primary colors at the same time. As shown in FIG. 5A, another method for sequentially displaying the sub-picture S120′ in this embodiment includes the following steps: displaying colorful Sub-picture S121'; display first color photo sub-picture S123; display second color photo sub-picture S124; and display third color photo sub-picture S125.

A colorful sub-picture S121' is displayed; as shown in FIG. 5B, a first color light and a second color light may be selected from the three different color lights, and the second backlight control signal and the second color light second by the first color light The backlight control signal cooperates with the third liquid crystal control signal to display a colorful sub-picture, and the first color light and the second color light are selected from the group consisting of red light, green light and blue light, and the third liquid crystal control signal can be less than or equal to the first The minimum of the second liquid crystal control signals of the color light and the second color light. For example, if the first color light is red light and the second color light is green light, the colorful sub-picture is actually a yellow photon picture, which is based on the second backlight control signal of red light and the green light The second backlight control signal is displayed in conjunction with the third liquid crystal control signal.

Displaying a first color photon screen S123; the second backlight control signal according to the first color light is matched with the operation result of the second liquid crystal control signal and the third liquid crystal control signal of the first color light for each pixel, wherein The calculation result may be the difference between the second liquid crystal control signal and the third liquid crystal control signal, but the method for generating the same operation result is not limited thereto, and the user can adjust the picture quality according to the desired display. Since the colorful sub-picture has displayed part of the first color light, the second liquid crystal control signal After the number is calculated with the third liquid crystal control signal, the first color photon screen is displayed by the operation result of the second backlight control signal and the liquid crystal control signal.

Displaying a second color photon picture S124; displaying the result of the second liquid crystal control signal and the third liquid crystal control signal of each pixel according to the second backlight control signal of the second color light, wherein the operation result is displayed It can be the difference between the second liquid crystal control signal and the third liquid crystal control signal. Similarly, since the colorful sub-picture has displayed part of the second color light, the second liquid crystal control signal needs to be operated with the third liquid crystal control signal, and then the second color photon is displayed by the operation result of the second backlight control signal and the liquid crystal control signal. Picture.

The third color photon screen S125 is displayed; and the second backlight control signal is matched with the third color light of the second liquid crystal control signal of each pixel according to the third color light. Because the colorful sub-picture does not display the third color light, the second liquid crystal control signal does not need to be operated with the third liquid crystal control signal, and can directly display the second backlight control signal of the third color light.

As shown in FIG. 5B, the colorful sub-picture can be changed to a yellow photon picture by displaying red light and green light, or can be changed to a cyan photon picture by displaying green light and blue light (Fig. Show), or display red and green light and turn into a magenta photon screen (not shown), then display the first, second, and third color photon screens sequentially, and the order of the color photon screens is displayed. Not limited.

Since the colorful sub-pictures have already displayed partial colors, it is possible to complement each of the color sub-pictures in order to complement the lack of colors in the colorful sub-pictures, and because more than one colorful sub-picture is inserted, the time of each color photo-sub-picture display is also Relatively shortened, and reduce the contribution of the original color light to the image, thereby reducing the occurrence of color separation.

In order to better understand the contents of the embodiment, the following describes the method flow of the embodiment. As shown in FIG. 6A, it is a flow S120 for generating a second backlight control signal 21, a second liquid crystal control signal 22, and a third liquid crystal control signal 23 in a display area in FIG.

As shown in FIG. 6A, by analyzing the input image signal S111, The first backlight control signal 11 of each color light and the first liquid crystal control signal 12 in each pixel are obtained. It can be seen from FIG. 6A that the first backlight control signal 11 of red light is 255, the first liquid crystal control signal 12 is 250, 248, 246, 246, etc., and the first backlight control signal 11 of green light is 255, first. The liquid crystal control signals 12 are 196, 195, 194, 194, etc., and the first backlight control signal 11 of blue light is 255, and the first liquid crystal control signals 12 are 92, 93, 93, 95, and the like.

The second backlight control signal S113 is generated according to the first liquid crystal control signal of each color light. For example, the maximum value of the first liquid crystal control signal 12 is used as the second backlight control signal 21 of each color light. Therefore, in this display area, the second backlight control signal 21 of the red light is 250, and the second backlight control of the green light is The signal 21 is 196, and the second backlight control signal 21 of blue light is 95.

Next, a second liquid crystal control signal S114 of each color light is generated. Since the color image displayed last is equal to the intensity of the color image light generated according to the input image signal, the second liquid crystal control signal 22 of each pixel can be generated according to the formula (1). If the gamma factor in the formula (1) is 2, after the calculation, the second liquid crystal control signal 22 of the red light is 252, 250, 248, 248, etc., and the second liquid crystal control signal 22 of the green light is 244. , 222, 221, 221, etc., and the second liquid crystal control signal 22 of blue light is 151, 152, 152, 156, etc.

Finally, a third liquid crystal control signal S115 is generated. It is assumed that the minimum value LCmin of the second liquid crystal control signal 22 of the red light, the green light and the blue light is set to the third liquid crystal control signal 23, so the third liquid crystal control signal 23 is 113, but the user can also display the image according to the image. The requirement is to select a value smaller than the minimum value LCmin of the second liquid crystal control signal 22 as the third liquid crystal control signal 23.

As shown in FIG. 6B, the sub-picture S120 is sequentially displayed according to the control signal of each color light. The second backlight control signal 21 according to the red light, the green light, and the blue light is simultaneously displayed with the third liquid crystal control signal 23 to display the colorful sub-picture S121. The third liquid crystal control signal 23 is the red light, the green light, and the blue light. The minimum value LCmin of the two liquid crystal control signals 22, so the colorful sub-picture shows the partial color of the color image to be displayed.

Then, each color photon screen S122 is sequentially displayed, and the red photon screen, the green photon screen, and the blue photon screen are sequentially displayed, but the order of the color photon screen display is not limited. In the order shown in FIG. 6B, the first color photon picture is a red photon picture, the second color photon picture is a green photon picture, and the third color photon picture is a blue photon picture.

For example, the second backlight control signal 21 of the red photon picture is 250, and is matched with the operation result 24 of the second liquid crystal control signal 22 and the third liquid crystal control signal 23 (ie, LC _{HDR_R} ), for example, 139, 137, 135, 135. ...the red photon picture is displayed, and the second backlight control signal 21 of the green photon picture is 196, and the second backlight control number of the blue photon picture is 95, which is respectively matched with the second liquid crystal control signal 22 and the third liquid crystal. The operation result 24 of the control signal 23 (ie, LC _{HDR_G} , LC _{HDR_B} ) displays a green photon picture and a blue photon picture. Displaying a color image by the above method can reduce the occurrence of color separation.

The embodiments are described to illustrate the features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the present invention and to implement the present invention without limiting the scope of the present invention. Equivalent modifications or modifications made by the spirit of the disclosure should still be included in the scope of the claims described below.

S100‧‧‧Reducing the display method of color separation of liquid crystal display

S110‧‧‧ generates control signals for each sub-picture

S120‧‧‧Sequence display sub-screen

Claims (10)

A liquid crystal display display method for driving a liquid crystal display having a backlight module and a plurality of pixels to display a color image, the display method comprising the steps of: displaying a colorful sub-picture according to an input image signal Displaying, according to the input image signal, a first color photon picture, a second color photo sub picture, and a third color photo sub picture; and rooting through the colorful sub picture, the first color photo sub picture, the second color photo sub picture, and The third color photon picture is blended into the color image. The display method of claim 1, wherein the color image comprises a first color light component, a second color light component, and a third color light component, wherein the backlight module is provided according to a first backlight control signal. Backlighting and respectively matching each pixel according to each color light to adjust the transmittance of each color of the first liquid crystal control signal of the pixel; displaying the first to third color photons according to the input image signal The screen includes a second backlight control signal according to one of the color lights in the at least one display area of the liquid crystal display, and the color light is operated on one of the second liquid crystal control signals and one third liquid crystal control signal of each of the pixels. The color photon screen is displayed, and the colorful sub-picture is displayed according to the input image signal, and the second liquid crystal control signal is displayed according to the second backlight control signal of each color light in each display area to display the colorful sub-picture; The second backlight control signal of each color light in each display area is responsive to the first liquid crystal control signals; in each display area Each of the second liquid crystal control signals for each of the pixels is responsive to the second backlight control signal; and the third liquid crystal control signal is responsive to a minimum of the second liquid crystal control signals . The display method of claim 2, wherein each display area is The second backlight control signal of the color light is the maximum of the first liquid crystal control signals. The display method of claim 2, wherein the second backlight control signal of each color light in each display area is an average of the first liquid crystal control signals. The display method of claim 2, wherein the second backlight control signal of each color light in each display area is an average of the first liquid crystal control signals divided by the first liquid crystal control One of the total order values of the signal, and the root of the root is multiplied by the total order value. The display method according to any one of claims 2 to 5, wherein each of the second liquid crystal control signals of each of the pixels in each of the display regions is calculated according to the following equation: GL _HDR = (BL _Full / BL _HDR ) ^{1 / r} * GL _Full where GL _{HDR is} the second liquid crystal control signal, BL _{Full is} the first backlight control signal, BL _{HDR is} the second backlight control signal, r is a Gamma factor, and GL _{Full is} the first liquid crystal control signal. The display method of claim 6, wherein the third liquid crystal control signal is less than or equal to a minimum of the second liquid crystal control signals. The display method of claim 6, wherein the operation result is a difference between the second liquid crystal control signal and the third liquid crystal control signal. The display method of claim 6, wherein the backlight module is configured according to the liquid crystal when the color sub-picture, the first color photo sub-picture, the second color photo sub-picture, and the third color photo sub-picture are displayed. Multiple display areas of the display provide different shades of light. The display method of claim 2, wherein the colorful sub-picture includes a first color light component, a second color light component, and a third color light component; the first color light component in the colorful sub-picture And the first color photon picture is used to display the first color light component in the color image; the second color light component and the second color photon picture in the colorful sub-picture are used to display the second color image. a color light component; and the third color light component and the third color photon screen in the colorful sub-picture are used to display the third color light component in the color image.