KR100937709B1 - Method for illuminating of liquid crystal display device and liquid crystal display device using the same - Google Patents

Abstract

A lighting method in a liquid crystal display device for improving display quality and a liquid crystal display device using the same are disclosed. The illumination method in the liquid crystal display device divides the effective display area in which an image is displayed into a plurality of display areas, and emits light with differential luminance according to the gradation value for each display area. Accordingly, the liquid crystal display may adjust the brightness of light in response to various color distributions of the image, and may improve the brightness and contrast ratio.

Contrast Ratio, Brightness, Light Control

Description

Lighting method in liquid crystal display device and liquid crystal display device using the same {METHOD FOR ILLUMINATING OF LIQUID CRYSTAL DISPLAY DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME}

1 is a flowchart illustrating a light control process of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a plan view illustrating the liquid crystal display panel illustrated in FIG. 2.

4 is a cross-sectional view taken along the line A-A of FIG. 2.

FIG. 5 is a plan view illustrating the lamp illustrated in FIG. 2.

6 is an exploded perspective view illustrating a liquid crystal display according to another exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along the cutting line B-B shown in FIG. 6.

<Description of the symbols for the main parts of the drawings>

100: liquid crystal display panel assembly 200, 600: backlight assembly

210, 610: lamp 620: luminance control member

300: mold frame 400: top chassis

The present invention relates to an illumination method in a liquid crystal display device and a liquid crystal display device using the same, and more particularly, to an illumination method and a liquid crystal display device using the same for improving the contrast ratio.

In general, a liquid crystal display device includes a liquid crystal display panel for displaying an image using light and a backlight assembly for generating light.

The backlight assembly is designed primarily for uniformly providing light to an effective display area in which an image of a liquid crystal display panel is displayed.

Recently, the development direction of the liquid crystal display device has been a variety of ways to secure high brightness to improve the display quality. Due to this trend, the luminance of the liquid crystal display is improved, but there is a limit to increasing the contrast ratio (C / R).

That is, in the case of a high brightness liquid crystal display device, the backlight assembly provides uniform high brightness light to the effective display area. Accordingly, the high brightness liquid crystal display device may display a vivid color as the gray scale value is closer to white. However, a high brightness liquid crystal display device exhibits a bluish color as the grayscale value is closer to black due to high brightness, and thus cannot display a clear color. For example, black belonging to the low gradation may be expressed as a color close to gray.                         

Accordingly, when a high brightness liquid crystal display displays an image in which a color belonging to a low gradation and a color belonging to a high gradation coexist, the color of the high gradation is clearly displayed, but the color belonging to the low gradation is not clearly displayed. The contrast ratio is reduced and the display quality is degraded.

It is an object of the present invention to provide an illumination method in a liquid crystal display device for improving display quality.

It is also an object of the present invention to provide a liquid crystal display device using the above-described illumination method.

In the liquid crystal display device according to one aspect for realizing the above object of the present invention, an illumination method divides an effective display area for displaying an image into a plurality of display areas. Image data corresponding to the image is received to extract grayscale values corresponding to the display area, respectively. The luminance value of light provided to the effective display area is set for each unit display area according to the gray scale value. Light having luminance values corresponding to each unit display area is emitted to the effective display area.

In addition, a liquid crystal display device according to one feature for realizing the above object of the present invention comprises a liquid crystal display panel and a light supply unit for displaying an image. The liquid crystal display panel is composed of a plurality of display areas for displaying an image corresponding to image data, and displays an image by using first light having a differential brightness according to a gray scale value corresponding to each unit display area. The light supply unit provides first light to the liquid crystal display panel.                     

According to the illumination method of the liquid crystal display device and the liquid crystal display device using the same, the brightness and the contrast ratio can be improved by adjusting the brightness of the light corresponding to various color distributions of the image, thereby improving the display quality.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

1 is a flowchart illustrating a light control process of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to Fig. 1, first, an effective display area in which an image is displayed is divided into a plurality of display areas (step S100).

Image data corresponding to an image is received from the outside (step S200), and a gray value of an image corresponding to each display area is extracted using the image data (step S300). In this case, the range of the gray scale value is formed differently according to the specification of the liquid crystal display.

A luminance value of light incident on the display area is set according to the gray scale value (step S400). In this case, the luminance value of the light increases as the gray value approaches the high gray.

The light having the differential luminance is emitted to the effective display area according to the luminance value set for each display area (step S500). Therefore, the light incident on the effective display area has a different luminance value for each display area.

As described above, the light adjusting method in the liquid crystal display according to the present invention sets the brightness of the light incident on the effective display area differently according to the gradation values corresponding to the respective display areas, thereby directing the high brightness liquid crystal display. The device can also clearly display low gradation colors. Accordingly, the liquid crystal display device can improve the brightness and the contrast ratio at the same time, thereby improving the display quality.

2 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 3 is a plan view illustrating the liquid crystal display panel shown in FIG. 2.

2 and 3, the liquid crystal display device 500 according to the present invention includes a liquid crystal display panel assembly 100 for displaying an image using light, and generates the light to generate the liquid crystal display panel assembly 100. The backlight assembly 200 includes a mold frame 300 for accommodating the liquid crystal display panel assembly 100, and a top chassis 500 facing the mold frame 300 to face each other.

More specifically, the liquid crystal display panel assembly 100 may include a liquid crystal display panel 110 displaying a plurality of images, a plurality of data side and gate side tape carrier packages (TCP) 120 and 125, and The data side and the gate side printed circuit boards 130 and 135 are included.

As shown in FIG. 3, the liquid crystal display panel 110 has an effective display area DP in which the image is displayed. The effective display area DP includes a plurality of display areas US, and the plurality of display areas US are arranged in a matrix. In this case, the plurality of display areas US may be formed to correspond to the plurality of unit pixels, respectively, and one display area may include a predetermined number of unit pixels.

Specifically, the liquid crystal display panel 110 includes a thin film transistor substrate (TFT) 111, a color filter substrate 112 and a TFT substrate 111 that are coupled to face the TFT substrate 111. ) And a first liquid crystal layer (not shown) injected between the color filter substrate 112.

The TFT substrate 111 is a transparent substrate on which a switching element TFT (not shown) is arranged in a matrix form. In this case, the TFT is located in each of the unit pixels. The color filter substrate 112 provided to face the TFT substrate 111 is a transparent substrate in which RGB pixels, which are color pixels expressing a predetermined color using the light, are formed by a thin film process.

The source side of the TFT substrate 111 is connected with the plurality of data side TCPs 120, and the gate side of the TFT substrate 111 is connected with the plurality of gate side TCPs 125. The data side and gate side TCPs 120 and 125 apply a driving signal for driving the liquid crystal display panel 110 and a timing signal for controlling the driving timing to the liquid crystal display panel 110.

The plurality of data side and gate side TCPs 120 and 125 are connected to the data side and gate side printed circuit boards 130 and 135, respectively. The data side and gate side printed circuit boards 130 and 135 receive image signals from the outside, generate the driving signals and timing signals, and apply the driving signals and timing signals to the plurality of data side and gate side TCPs 120 and 125.

The backlight assembly 200 is provided below the liquid crystal display panel assembly 100 to provide the light to the liquid crystal display panel 110.

The backlight assembly 200 includes a plurality of lamps 210 for generating light, a diffusion plate 220 for diffusing the light, a diffusion sheet 230, and a bottom chassis 240 that is a storage container.

Specifically, the plurality of lamps 210 are positioned to correspond to the plurality of display areas US, respectively. The plurality of lamps 210 includes a light emitting diode. The plurality of lamps 210 emits light having differential luminance according to the grayscale value corresponding to each display area.

That is, each lamp has a brightness that varies depending on the gradation value for displaying an image corresponding to the display area among the images displayed in the effective display area DP. Accordingly, each of the lamps emits light having different luminance values according to the gray scale value of the display area. In addition, the luminance of the plurality of lamps 210 appears differently every time the image changes.

The diffusion plate 220 and the diffusion sheet 230 are provided on the plurality of lamps 210. The diffusion plate 220 and the diffusion sheet 230 diffuse the light incident from the plurality of lamps 210 and provide the diffusion plate 220 to the liquid crystal display panel 110.

The bottom chassis 240 is provided below the plurality of lamps 210. The bottom chassis 240 sequentially receives the plurality of lamps 210, the diffusion plate 220, and the diffusion sheet 230.

The mold frame 300 is provided on the diffusion sheet 230. The mold frame 300 is coupled to the bottom chassis 240 so as to face each other to fix the plurality of lamps 210, the diffusion plate 220, and the diffusion sheet 230 to the bottom chassis 240. . The mold frame 300 accommodates the liquid crystal display panel 110 and is coupled to the top chassis 400 to face each other.

The top chassis 400 is coupled to the mold frame 300 and the bottom chassis 240 to cover the liquid crystal display panel 110 so that the effective display area DP opens. It is fixed to the mold frame 300.

4 is a cross-sectional view taken along the line A-A of FIG. 2.

Referring to FIG. 4, the plurality of lamps 210 are disposed to correspond to the plurality of display areas US, respectively. The plurality of display areas US includes first to fourth display areas US1, US2, US3, and US4. The plurality of lamps 210 includes first to fourth lamps 211, 212, 213, and 214.

In this case, the first lamp 211 is positioned to correspond to the first display area US1, and the second lamp 212 is located to correspond to the second display area US2. The third lamp 213 is positioned to correspond to the third display area US3, and the fourth lamp 214 is located to correspond to the fourth display area US4.

5 is a plan view illustrating the lamp unit illustrated in FIG. 2.

Referring to FIG. 5, the plurality of lamps 210 are connected to the light control unit 250 that controls the brightness of each lamp and provides power. In this case, the plurality of lamps 210 and the light control unit 250 are connected by power supply lines 51 and 52 for applying the power applied from the light control unit 250 to the plurality of lamps 210. do.

The light controller 250 receives an image signal corresponding to the image from the outside and extracts a gray value corresponding to each of the display areas US1, US2, US3, and US4. The light controller 250 adjusts the brightness of each of the lamps 211, 212, 213, and 214 according to the grayscale values corresponding to the display areas US1, US2, US3, and US4.

That is, the luminance of the first to fourth lamps 211, 212, 213, and 214 is determined according to respective grayscale values corresponding to the first to fourth display areas US1, US2, US3, and US4. In this case, since the gradation value changes according to the image, the luminance of the plurality of lamps 210 also appears differently according to the image.

Each of the lamps 211, 212, 213, and 214 increases in brightness as the gray level value increases, and decreases in brightness as the gray level value is low. For example, when the gray value of the first display area US1 is 1 and the gray value of the second display area US2 is 10, the brightness of the first lamp 211 is the second lamp ( 212) is lower than the luminance. In this case, the luminance of each of the lamps 211, 212, 213, and 214 may be different for each gray value represented by the LCD 500, or for each group of gray values grouped in a specific unit. It may appear different.

As the gray level value is higher, the color to be expressed is clearly and clearly displayed when the luminance of incident light is higher, and the color to be expressed is accurately and vividly displayed when the brightness of the incident light is lower as the gray level value is lower. Accordingly, the liquid crystal display device 500 differentially forms the luminance of the plurality of lamps 210 according to the grayscale values of the plurality of display regions US by using the light controller 250, thereby providing one screen. Colors with a low gradation value and colors with a high gradation value can be displayed clearly.                     

6 is an exploded perspective view illustrating a liquid crystal display according to another exemplary embodiment of the present invention. In the present exemplary embodiment, the liquid crystal display 700 has the same configuration as the liquid crystal display 500 shown in FIG. 2 except for the backlight assembly 600. Therefore, in the description of this embodiment, the same reference numerals are assigned to the same components as those of the liquid crystal display device 500, and the description thereof will be omitted.

Referring to FIG. 6, a liquid crystal display device 700 according to the present invention includes a liquid crystal display panel assembly 100 for displaying an image using light, a backlight assembly 600 generating the light, and the liquid crystal display panel assembly. A mold frame 300 for accommodating the 100 and a top chassis 500 coupled to the mold frame 300 so as to face each other.

In more detail, the liquid crystal display panel assembly 100 displays an image corresponding to an image signal using light provided from the backlight assembly 600.

The backlight assembly 600 is provided under the liquid crystal display panel assembly 100. The backlight assembly 600 may include a plurality of lamps 610 for generating the light, a diffusion plate 220 and a diffusion sheet 230 for diffusing the light, and a luminance value corresponding to each display area of the luminance of the light. The brightness control member 620, the reflecting plate 630 and the bottom chassis 240 to be changed according to.

Specifically, the plurality of lamps 610 are disposed on the reflector plate 640 to generate the light.                     

The diffusion plate 220 and the diffusion sheet 230 for diffusing the light are provided on the plurality of lamps 610.

The luminance adjusting member 620 is interposed between the liquid crystal display panel 110 and the diffusion sheet 230. The brightness adjusting member 620 adjusts the brightness of the light incident from the diffusion sheet 230 according to the gray value of each display area and emits the light. Therefore, the luminance adjusting member 620 has a different luminance of light emitted for each region corresponding to each display region.

The source side of the brightness adjusting member 620 is connected to a plurality of data side TCPs 625a, and the gate side is connected to a plurality of gate side TCPs 625b.

The plurality of data side and gate side TCPs 625a and 625b apply a driving signal for driving the luminance adjusting member 620 and a timing signal for controlling driving timing to the luminance adjusting member 620.

The luminance adjusting member 620 determines an arrangement angle of the liquid crystal corresponding to each display area according to the driving signal and the timing signal applied from the data side and the gate side TCPs 625a and 625b. Since the brightness of the light incident on the brightness adjusting member 620 varies according to the arrangement angle of the liquid crystal, light having a differential brightness for each display area is emitted.

The plurality of data side and gate side TCPs 625a and 625b are connected to the data side and gate side printed circuit boards 626a and 626b, respectively. The data side and gate side printed circuit boards 626a and 626b receive the image signals from the outside, generate the driving signals and timing signals, and apply them to the plurality of data side and gate side TCPs 120 and 125.

The reflector 630 is provided under the plurality of lamps 610. The reflection plate 630 reflects the light leaked from the plurality of lamps 610 back into the diffusion plate 220 to improve the efficiency of the light.

The bottom chassis 240, which is a storage container, is provided under the reflective plate 630, and sequentially accommodates the reflective plate 630, the plurality of lamps 610, the diffusion plate 220, and the diffusion sheet 230. do.

The mold frame 300 is provided on the diffusion sheet 230. The mold frame 300 sequentially receives the brightness adjusting member 620 and the liquid crystal display panel 110.

The top chassis 400 is provided on the liquid crystal display panel 110. The top chassis 400 is coupled to the mold frame 300 and the bottom chassis 240 to cover the liquid crystal display panel 110 so that the effective display area DP is opened. And fix the liquid crystal display panel 110 to the mold frame 300.

As described above, the luminance adjusting member 620 according to the present invention provides the liquid crystal display panel 110 with light having differential luminance according to the gray level value of each display area. Accordingly, the liquid crystal display device 700 may improve contrast while maintaining high brightness, thereby improving display quality.

FIG. 7 is a cross-sectional view taken along the cutting line B-B of FIG. 6 and illustrates only the liquid crystal display panel 100 and the luminance adjusting member 620 in order to more clearly show the luminance adjusting member 620.

Referring to FIG. 7, the liquid crystal display panel 110 is interposed between a TFT substrate 111, a color filter substrate 112 on which color pixels are formed, and the TFT substrate 111 and the color filter substrate 112. And a first liquid crystal layer 113.

The TFT substrate 111 is a substrate on which a first array layer 12 for applying a pixel voltage to the liquid crystal layer 113 is formed on the first insulating substrate 11. The first array layer 12 includes a TFT 13 as a switching element. The TFT 13 is positioned on the first insulating substrate 11 in a matrix form and is located for each unit pixel.

The color filter substrate 112 is a material for applying a common voltage to the color filter layer 22 and the first liquid crystal layer 113 expressing a predetermined color by using light on the second insulating substrate 21. 1 is a substrate on which a common electrode 23 is formed.

Specifically, the color filter layer 22 expresses a predetermined color by using light provided from the brightness adjusting member 620. The first common electrode 23 for applying a common voltage to the first liquid crystal layer 113 is deposited on the color filter layer 22.

Meanwhile, the luminance adjusting member 620 provided under the liquid crystal display panel 110 may be coupled to the lower substrate 621 and the lower substrate 621 on which the plurality of light control TFTs 43 are formed. And a second liquid crystal layer 623 interposed between the upper substrate 622 and the upper and lower substrates 621 and 622.                     

In detail, the lower substrate 621 includes a third insulating substrate 61 and a second array layer 62 formed on the third insulating substrate 61. The second array layer 62 includes the plurality of light control TFTs 63. The plurality of light control TFTs 63 are disposed in the form of a matrix and are respectively located in areas corresponding to the plurality of unit pixel areas US. The plurality of light control TFTs 63 vary the amount of voltage applied to the second liquid crystal layer 623 according to the grayscale values of the corresponding plurality of display regions US.

For example, when the plurality of light control TFTs 63 is formed of the first TFT 63a and the second TFT 63b, the first light control TFT 63a is selected from among the plurality of display areas US. The second light control TFT 63b is positioned to correspond to the first display area US1, and the second light control TFT 63b is positioned to correspond to the second display area US2.

The first light control TFT 63a applies a different voltage to the second liquid crystal layer 623 according to the grayscale value corresponding to the first display area US1. In this case, when the gray scale value of the first display area US1 is high, the first light control TFT 63a applies a high voltage to the second liquid crystal layer 623 to display light having high luminance. Exit to area US1. When the gray scale value of the first display area US1 is low, the first light control TFT 63a applies a low voltage to the second liquid crystal layer 623 to transmit light having low luminance to the first display area. Exit to US1).

 In the present embodiment, since the second light control TFT 63b has the same structure and performs the same function as the first light control TFT 63a, the description of the second light control TFT 63b is omitted. Let's do it.

The upper substrate 622 coupled to the lower substrate 621 opposite to each other includes a fourth insulating substrate 64 and a second common electrode 65 formed on the fourth insulating substrate 65.

As described above, the luminance adjusting member 620 according to the present invention arranges the plurality of light adjusting TFTs 63 corresponding to the plurality of display regions US, respectively. Accordingly, the luminance adjusting member 620 adjusts the luminance of light emitted to the display region according to the grayscale value corresponding to each of the display regions US1, US2, and US3. Thus, the liquid crystal display 700 may improve contrast while maintaining high brightness.

As described above, according to the present invention, the liquid crystal display device can improve the display quality by adjusting the brightness of the light corresponding to various color distributions of the image, thereby improving the display quality.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (7)

(a) dividing an effective display area for displaying an image into a plurality of display areas; (b) receiving image data corresponding to the image and extracting a gray value corresponding to each of the display areas; (c) changing the luminance value of the first light provided to the effective display area differentially for each of the display areas according to the grayscale value based on the second light generated from the light source; And and (d) emitting the first light having luminance corresponding to the display area to the effective display area, respectively. A liquid crystal display panel comprising a plurality of display areas for displaying an image corresponding to image data, the liquid crystal display panel for displaying the image using first light having a differential brightness according to a gray scale value corresponding to each display area; And A light source including a light source for generating a second light, and a brightness controller configured to change the second light into the first light having a differential brightness according to a gray value corresponding to the display area, and emit the light to the liquid crystal display panel; Liquid crystal display comprising a supply unit. The method of claim 2, wherein the light supply unit, And a light controller for controlling the luminance of each light source based on the gray value corresponding to each of the display areas using the image data. The liquid crystal display of claim 3, wherein the luminance of the light source is proportional to a gray value of a display area corresponding to the light source. The liquid crystal display of claim 3, wherein the plurality of light sources are formed of light emitting diodes. delete The method of claim 1, wherein the brightness control unit, A first substrate corresponding to the plurality of display areas, the first substrate having a plurality of thin film transistors for applying a voltage according to the gray scale value; A second substrate coupled to the first substrate so as to face each other; And And a liquid crystal layer interposed between the first and second substrates and changing the angle of the liquid crystal according to the voltage to change the second light into the first light.

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