LCD improving color shift at large viewing angle

An LCD includes a backlight module, an array substrate, and a color filter layer. The color filter layer includes a first filter unit, a second filter unit and a black matrix unit. A transmittance rate of the second filter unit is larger than that of the first filter unit. The black matrix layer is connected between the first filter unit and second filter unit. The width of the black matrix unit is larger than that of the third black matrix unit. The width of the black matrix unit facing the first filter unit is larger than that of the black matrix unit facing the second filter unit. This kind of asymmetrical black matrix layer not only best prevents lowering the pixel aperture ratio, but also improves color shift of images when light goes through pixels of low transmittance as pixels of high transmittance are turned off.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Stage of International Application No. PCT/CN2015/095130, filed Nov. 20, 2015, which in turn claims the benefit of China Patent Application No. 201510777556.6, filed Nov. 12, 2015.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display (LCD), and more specifically, to a LCD that improves color shift at large viewing angle by adjusting the width of black matrix layers.

2. Description of the Prior Art

As display technology advances, people pay more and more attention to the display quality of display devices, which are developing wider viewing angles. However, a liquid crystal display (LCD) with a wide viewing angle usually has a problem: color shift at large viewing angles. It is mainly because of light leakage of adjacent pixels that affects color purity shown by pixels. For example, when the LCD shows a red image, the light goes through red pixels and adjacent green pixels are turned off. But some light still goes through the green pixels and thus the red image, when seen from a large viewing angle, has a yellowish color.

In addition, the resolution of LCDs gets higher and higher, and the area of pixels becomes smaller and smaller. To maintain a specific transmittance rate of pixels and prevent energy consumption increase or brightness reduction, the width of a black matrix between two pixels of LCDs has become narrower and narrower. However, during the process of manufacturing a LCD, a minor mismatch of a color filter substrate and array substrate will result in the shifting of black matrixes. Therefore, from a large viewing angle, viewers will still see color shift resulted from the light leakage of adjacent pixels.

SUMMARY OF THE INVENTION

An object of the present invention is mainly to solve the technical problem of color shift of images at a large viewing angle resulted from the light leakage of adjacent pixels.

According to the present invention, a liquid crystal display (LCD), comprises: a backlight module for emitting light; an array substrate disposed on the backlight module, comprising a plurality of data lines, comprising a first data line, a second data line and a third data line for transmitting data signals; a black matrix layer for preventing light leakage; a liquid crystal layer, disposed between the black matrix layer and the array substrate, comprising liquid crystal molecules for controlling the twist of liquid crystal molecules based on the data signals; and a color filter layer. The color filter layer comprises: a first filter unit for producing light of a first color when light passes through, a second filter unit for producing light of a second color when light passes through, of transmittance rate larger than that of the first filter unit, and a third filter unit, for producing light of a third color when light passes through, of transmittance rate larger than that of the first filter unit. The black matrix layer comprises: a first black matrix unit, corresponding to the joint of the first and second filter units; a second black matrix unit, corresponding to the joint of the second and third filter units; a third black matrix unit, corresponding to the joint of the first and third filter units; the width of the first black matrix unit is larger than that of the third black matrix unit. The width of the second black matrix unit is larger than that of the third black matrix unit, and the width of the first black matrix unit is larger than that of the second black matrix unit.

In one aspect of the present invention, the first black matrix unit aligns to a first data line and bases on the center line of the first data line, and the width of the first black matrix unit facing the second filter unit is larger than that facing the first filter unit.

In another aspect of the present invention, the second black matrix unit aligns to a second data line and bases on the center line of the second data line, and the width of the second black matrix unit facing the second filter unit is larger than that facing the third filter unit.

In another aspect of the present invention, the first black matrix unit connects between the first and second filter units, the second black matrix unit connects between the second and third filter units, and the third black matrix unit connects the first and third filter units.

In still another aspect of the present invention, the first black matrix unit faces but does not contact the joint of the first and second filter units, the second black matrix unit faces but does not contact the joint of the second and third filter units, and the third black matrix unit faces but does not contact the joint of the first and third filter units.

In yet another aspect of the present invention, the first filter unit is a red filter unit, the second filter unit is a green or white filter unit, and the third filter unit is a blue filter unit.

According to the present invention, a liquid crystal display (LCD), comprises: a backlight module for emitting light; an array substrate disposed on the backlight module, comprising a plurality of data lines, comprising a first data line, a second data line and a third data line for transmitting data signals; a black matrix layer for preventing light leakage; a liquid crystal layer, comprising liquid crystal molecules, for controlling the twist of liquid crystal molecules based on the data signals; and a color filter layer. The color filter layer comprises: a first filter unit for producing light of a first color when light passes through, a second filter unit for producing light of a second color when light passes through, of transmittance rate larger than that of the first filter unit, a third filter unit for producing light of a third color when light passes through, of transmittance rate larger than that of the first filter unit. The black matrix layer comprises: a first black matrix unit, corresponding to the joint of the first and second filter units; a second black matrix unit, corresponding to the joint of the second and third filter units; a third black matrix unit, corresponding to the joint of the first and third filter units; the width of the first black matrix unit is larger than that of the third black matrix unit.

In one aspect of the present invention, the width of the second black matrix unit is larger than that of the third black matrix unit.

In another aspect of the present invention, the width of the first black matrix unit is larger than that of the second black matrix unit.

In another aspect of the present invention, the liquid crystal layer is disposed between the black matrix layer and the array substrate.

In another aspect of the present invention, the first black matrix unit aligns to a first data line and bases on the center line of the first data line, and the width of the first black matrix unit facing the second filter unit is larger than that facing the first filter unit.

In another aspect of the present invention, the second black matrix unit aligns to a second data line and bases on the center line of the second data line, and the width of the second black matrix unit facing the second filter unit is larger than that facing the third filter unit.

In another aspect of the present invention, the first black matrix unit connects between the first and second filter units, the second black matrix unit connects between the second and third filter units, and the third black matrix unit connects the first and third filter units.

In another aspect of the present invention, the first black matrix unit faces but does not contact the joint of the first and second filter units, the second black matrix unit faces but does not contact the joint of the second and third filter units, and the third black matrix unit faces but does not contact the joint of the first and third filter units.

In still another aspect of the present invention, the black matrix layer is disposed between the liquid crystal layer and the array substrate.

In yet another aspect of the present invention, the first filter unit is a red filter unit, the second filter unit is a green or white filter unit, and the third filter unit is a blue filter unit.

Comparing to current technology, the present invention provides a LCD with an asymmetrical black matrix layer. The width of the black matrix unit on both sides of the filter unit of high transmittance rate (e.g. green or white filter unit) is larger than that of the black matrix unit between two filter unit of low transmittance rate (e.g. red or blue filter unit). More specifically, when the asymmetrical black matrix layer locates on the side that is away from the backlight module (i.e. close to viewers), the width of the black matrix unit facing the filter unit of high transmittance rate is larger than that of the black matrix unit facing the filter unit of low transmittance rate. When the asymmetrical black matrix layer locates on the side that is closer to the backlight module (i.e. away from viewers), the width of the black matrix unit facing the filter unit of low transmittance rate is larger than that of the black matrix unit facing the filter unit of high transmittance rate. This kind of asymmetrical black matrix layer not only best prevents lowering the pixel aperture ratio, but also improves color shift of images when light goes through pixels of low transmittance as pixels of high transmittance are turned off.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer toFIG. 1andFIG. 2.FIG. 1is a schematic diagram of a LCD100of the present invention.FIG. 2is a cross-sectional view of the LCD100of a first embodiment of the present invention. The LCD100of the present invention comprises a LCD panel106and a backlight module108. The LCD panel106comprises an array substrate120, a color filter layer122and a liquid crystal layer124. The liquid crystal layer124locates between the array substrate120and color filter layer122. The color filter layer122comprises a black matrix layer125and a color film layer126. The LCD panel106, through the color film layer126, separates the light into three primary colors, red, green and blue, so to show color images. The black matrix layer125is for preventing light leakage. The array substrate120comprises a plurality of data lines102, scan lines104and pixel units110arranged in arrays. Each pixel unit110electrically connects to one data line102and one scan line104. The backlight module108comprises a substrate111and a plurality of backlight sources112, which are disposed on the substrate111. The plurality of backlight sources112can be light-emitting diodes (LED), organic LED (OLED) or quantum dots (QD). The LCD of the present invention can be applied to flat or curved display device. When the LCD100applies to a curved display device, the LCD panel106and backlight module108appear in a curved shape, with the former being disposed on the latter.

A method for driving the LCD panel106is as follows: a scan signal is outputted by the gate driver22and inputs through scan line104, so that a pixel unit110connected to the scan line104receives data signals outputted by the source driver24, thus is charged with necessary voltage. Liquid crystals above the pixel unit110twist according to the data signal, and further display different grey-scale images. The gate driver22outputs scan signals line by line through a plurality of scan lines104, and then the gate driver24charges or discharges pixel units110of each line. Following the sequence, a full display of the LCD panel106can be completed.

As shown inFIG. 2, the color filter layer122and color film layer126can comprise red filter unit126R, green filter unit126G and blue filter unit126B. The LCD panel106separates the light into red, green and blue colors through the red filter unit126R, green filter unit126G and blue filter unit126B, and shows color images. Generally speaking, the transmittance rate of the red filter unit126R is smaller than that of the green filter unit126G but larger than that of the blue filter unit126B. The transmittance ratio of the green filter unit126G, red filter unit126R and blue filter unit126B of one of the display device is approximately 3.7:1.4:1. Therefore, the present embodiment takes the red filter unit126R as first filter unit of low transmittance rate, the green filter unit126G as second filter unit of high transmittance rate, and blue filter unit126B as third filter unit of low transmittance. However, the transmittance rate of the third filter unit is still lower than that of the first filter unit. InFIG. 2, the green filter unit126G is disposed between the red filter unit126R and the blue filter unit126B.

The black matrix layer125comprises a plurality of black matrix units comprising black matrix units125a,125b, and125c. The black matrix unit125aconnects between the green filter unit126G and red filter unit126R and aligns to a data line102a; the black matrix unit125bconnects between the green filter unit126G and the blue filter unit126B and aligns to a data line102b; the black matrix unit125cconnects between the red filter unit126R and blue filter unit126B and aligns to a data line102c. The width d12of the black matrix unit125ais larger than the width d13of the black matrix unit125c. More specifically, the black matrix unit125abases on the center line of the data line102ato which it aligns to. The width d2of the black matrix unit125afacing the green filter unit126G is larger than the width d1of the black matrix unit125afacing the red filter unit126R. Given that the width d2is larger than width d1, the light leaked from the green filter unit126G is less when viewers see from the right large viewing angle. For example, when a red image is displayed, liquid crystal molecules under the red filter unit126R twist because of data voltage of the data line102a, so that light can go through the red filter unit126R which filters red light. At the same time, part of the light going through the liquid crystal molecules under the red filter unit126R is blocked by the black matrix unit125aand cannot pass the green filter unit126G. Given that the width d2of the black matrix unit125ais larger, it can easily block the light going through the liquid crystal molecules under the red filter unit126R and beaming to the green filter unit126G by the large viewing angle, stopping the light from passing the green filter unit126G. Therefore, from the large viewing angle, viewers see red image that are purely red with no green light involved.

Please refer toFIG. 3.FIG. 3is a cross-sectional view of the LCD100of the second embodiment of the present invention. The color filter layer126can comprise a white filter unit126W, a red filter unit126R and a blue filter unit126B. The transmittance rate of the white filter unit126W that filters the white light is larger than the red filter unit126R and blue filter unit126B. Therefore, the white filter unit126W and green filter unit126G can serve as the second filter unit of high transmittance rate. The white filter unit126W is between the red filter unit126R and blue filter unit126B.

The black matrix layer125comprises a plurality of black matrix units comprising black matrix units125a,125b, and125c. The black matrix unit125aconnects between the white filter unit126W and blue filter unit126B and aligns to a data line102a; the black matrix unit125bconnects between the white filter unit126W and the red filter unit126R and aligns to a data line102b; the black matrix unit125cconnects between the blue filter unit126B and red filter unit126R and aligns to a data line102c. The width d12of the black matrix unit125ais larger than the width d13of the black matrix unit125c. More specifically, the black matrix unit125abases on the center line of the data line102ato which it aligns to. The width d2of the black matrix unit125afacing the white filter unit126W is larger than the width d1of the black matrix unit125afacing the blue filter unit126B. Given that the width d2is larger than width d1, the light leaked from the white filter unit126W is less when viewers see from the right large viewing angle. For example, when a blue image is displayed, liquid crystal molecules under the blue filter unit126B twist because of data voltage of the data line102a, so that light can go through the blue filter unit126B which filters red light. At the same time, part of the light going through the liquid crystal molecules under the blue filter unit126B is blocked by the black matrix unit125aand cannot pass the white filter unit126W. Given that the width d2of the black matrix unit125ais larger, it can easily block the light going through the liquid crystal molecules under the blue filter unit126B and beaming to the white filter unit126W by the large viewing angle, stopping the light from passing the white filter unit126W. Therefore, from the large viewing angle, viewers see blue image that are purely blue with no white light involved.

Please refer toFIG. 4.FIG. 4is a cross-sectional view of the LCD100of a third embodiment of the present invention. Items inFIG. 4marked with numbers the same as those inFIG. 2have the same functions, so no further explanation is provided here. A width d13of the black matrix unit125cis smaller than not only a width d12of the black matrix unit125a, but also a width d23of the black matrix unit125b. A width d2of the black matric unit125afacing the green filter unit126G is larger than a width d1of the black matric unit125afacing the red filter unit126R. The black matrix unit125baligns to and bases on the center line of the data line102b, with a width d2′ facing the green filter unit126G larger than a width d3facing the blue filter unit126B. The width d2′ can equal to the width d2. Or, the proportion of d2′ to d2can be adjusted according to the transmittance ratio of the red filter unit126R to green filter unit126G, and the transmittance ratio of the blue filter unit126B to the green filter unit126G. For example, if the transmittance ratio of the red filter unit126R to green filter unit126G is larger than that of the blue filter unit126B to green filter unit126G, the width d2can be adjusted to be slightly smaller than the width d2′. Through the present embodiment, the width of the black matrix units125aand125bthat locate on the left and right side of the green filter unit126G respectively can be widened, and thus the problem of color shift at large viewing angles at the right and left viewing angles can be improved.

Please refer toFIG. 5.FIG. 5is a cross-sectional view of the LCD100of a fourth embodiment of the present invention. Items inFIG. 5marked with numbers the same as those inFIG. 2toFIG. 4have the same functions, so no further explanation is provided here. The width d2of the black matrix unit125afacing the green filter unit126G (or the white filter unit126W) is larger than the width d1of the black matrix unit125afacing the red filter unit126R. The width d2′ of the black matrix unit125bfacing the green filter unit126G (or the white filter unit126W) is larger than the width d3of the black matrix unit125bfacing the blue filter unit126B. In addition, in the fourth embodiment, the area of the green filter unit126G (or the white filter unit126W) is larger than that of the red filter unit126R (or the blue filter unit126B). More specifically, a distance Pg between the center line of the first data line102aand the center line of the second data line102bis larger than a distance Pb between the center line of the second data line102band the center line of the third data line102c. Or, the distance Pg between the center line of the first data line102aand the center line of the second data line102bis larger than a distance Pr between the center line of the first data line102aand the center line of the third data line102c. The present embodiment not only changes the width of the black matrix units125aor125bor both, which locate on either side of the green filter unit126G (or the white filter unit126w), but also increases the area of the green filter unit126G (or the white filter unit126W), so to maintain the aperture ratio of the green filter unit126G (or the white filter unit126W). In other words, the present invention not only improves color shift at large viewing angles, but also maintains the aperture ratio of the pixels.

Please refer toFIG. 6.FIG. 6shows a cross-sectional view of the LCD100of a fifth embodiment of the present invention. Items inFIG. 6marked with numbers the same as those inFIG. 2have the same functions, so no further explanation is provided here. The black matrix layer125is disposed between the array substrate120and liquid crystal layer124. The black matrix layer125comprises a plurality of black matrix units—black matrix units125a,125band125c. The black matrix unit125aconnects between the green filter unit126G and red filter unit126R and aligns to the data line102a. The black matrix unit125bconnects between the green filter unit126G and blue filter unit126B and aligns to the data line102b. The black matrix unit125cconnects between the red filter unit126R and blue filter unit126B and aligns to the data line102c. The width d12of the black matrix unit125ais larger than the width d13of the black matrix unit125c, or the width d23of the black matrix unit125bis larger than the width d13of the black matrix unit125c. In the present embodiment, the black matrix unit125abases on the center line of the data line102ato which it aligns to. The width d2of the black matrix unit125afacing the green filter unit126G is larger than the width d1of the black matrix unit125afacing the red filter unit126R. The back matrix unit125baligns to the center line of the data line102b. The width d2′ of the black matrix unit125bfacing the green filter unit126G is larger than the width d3of the black matrix unit125B facing the blue filter unit126B. The width d2of the black matrix unit125ais larger than the width d1, therefore it is easier for the black matrix unit125ato block the light that comes from the liquid crystal molecules above the red filter unit126R and to be output through the green filter unit126G from the large viewing angle, so that the light cannot pass through the green filter unit126G. At this moment, the red images viewers see at the large viewing angle are doped with little green light and are purely red images. Similarly, because the width d2′ of the black matrix unit125bis larger than the width d3, the light that passes through the green filter unit126G is less. Thus it is easier for the black matrix unit125bto block the light that comes from the liquid crystal molecules above the blue filter unit126B and to be output through the green filter unit126G from the large viewing angle, so that the light cannot pass through the green filter unit126G. Therefore, the blue images that viewers see at the large viewing angle are doped with little green light and are purely blue images.

The green filter unit126G in the present embodiment can be substituted by the white filter unit. The principle and deployment method is the same as that of the embodiment shown inFIG. 3, so no more explanation is provided here.

Similarly, the area of the green filter unit126G (or the white filter unit126W) is smaller than that of the red filter unit126R (or the blue filter unit126B). More specifically, a distance Pg between the center line of the first data line102aand the center line of the second data line102bis shorter than a distance Pb between the center line of the second data line102band the center line of the third data line102c. Or, the distance Pg between the center line of the first data line102aand the center line of the second data line102bis shorter than a distance Pr between the center line of the first data line102aand the center line of the third data line102c.

Please refer toFIG. 1andFIG. 7.FIG. 7is a cross-sectional view of the LCD100of a sixth embodiment of the present invention. Items inFIG. 7marked with numbers the same as those inFIG. 2have the same functions, so no further explanation is provided here. A color film layer326is disposed on an array substrate320, and a liquid crystal layer124is disposed on the color film layer326. A black matrix layer325is disposed on the liquid crystal layer124to prevent light leakage. The color film layer326can comprise a red filter unit326R, green filter unit326G and blue filter unit326B. The green filter unit326G connects between the red filter unit326R and blue filter unit326B. A LCD panel306separates the light into three primary colors—red, green and blue—through the red filter unit326R, green filter unit326G and blue filter unit326B, so to show color images. The black matrix layer325comprises a plurality of black matrix units, such as a first black matrix unit325a, a second black matrix unit325band a third black matrix unit325c. The first black matrix unit325alocates at the joint of the green filter unit326G and the red filter unit326R, and aligns to the data line102a. The second black matrix unit325blocates at the joint of the green filter unit326G and the blue filter unit326B, and aligns to the data line102b. The third black matrix unit325clocates at the joint of the red filter unit326R and the blue filter unit326B and aligns to the data line102c. The width d12of the first black matrix unit325aand the width d23of the second black matrix unit325bis larger than the width d13of the third black matrix unit325c. The width d2of the black matrix unit325afacing the green filter unit326G is larger than the width d3of the black matrix unit325afacing the red filter unit326R. The black matrix unit325bbases on the center line of the data line302bto which it aligns to. The width d2′ of the black matrix unit325bfacing the green filter unit326G is larger than the width d3of the black matrix unit325bfacing the blue filter unit326B. Given that the transmittance ratio of the red filter unit326R to green filter unit326G is larger than that of the blue filter unit326B to green filter unit326G, the width d2can be adjusted to be slightly smaller than the width d2′.

The green filter unit326G in the present embodiment can be substituted by the white filter unit. The principle and deployment method is the same as that of the embodiment shown inFIG. 3, so no more explanation is provided here.

The size of the green filter unit326G (or a white filter unit326W) shown inFIG. 7can be larger than that of the red filter unit326R (or the blue filter unit326B). More specifically, a distance Pg between the center line of the first data line102aand the center line of the second data line102bis larger than a distance Pb between the center line of the second data line102band the center line of the third data line102c. Or, the distance Pg between the center line of the first data line102aand the center line of the second data line102bis larger than a distance Pr between the center line of the first data line102aand the center line of the third data line102c.

In another embodiment, a top black matrix layer and bottom black matrix layer can be disposed respectively on the opposite sides of the liquid crystal layer124. The design of the black matrix layer shown inFIG. 7can be applied to the deployment of the top black matrix layer, and the design of the black matrix layer and color filter layer shown inFIG. 6can be applied to the deployment of the bottom black matrix layer.

Comparing to current technology, the present invention provides a LCD with an asymmetrical black matrix layer. The width of the black matrix unit on both sides of the filter unit of high transmittance rate (e.g. green or white filter unit) is larger than that of the black matrix unit between two filter unit of low transmittance rate (e.g. red or blue filter unit). More specifically, when the asymmetrical black matrix layer locates on the side that is away from the backlight module (i.e. close to viewers), the width of the black matrix unit facing the filter unit of high transmittance rate is larger than that of the black matrix unit facing the filter unit of low transmittance rate. When the asymmetrical black matrix layer locates on the side that is closer to the backlight module (i.e. away from viewers), the width of the black matrix unit facing the filter unit of low transmittance rate is larger than that of the black matrix unit facing the filter unit of high transmittance rate. This kind of asymmetrical black matrix layer not only best prevents lowering the pixel aperture ratio, but also improves color shift of images when light goes through pixels of low transmittance as pixels of high transmittance are turned off.