The method of a kind of CSTN LCD of high chroma and realization high chroma thereof
[technical field]
The present invention relates to a kind of CSTN (coler Super Twisted Nematic, be the colorful ultra-twist nematic phase) LCD, particularly relate to and can realize NTSC (NTSC's standard) than the CSTN LCD greater than 45% high chroma, the color rendering scope can compare favourably with TFT.
[background technology]
In order to attract the consumer, increasing mobile phone manufacturer begins to make colour screen handset, and the mobile phone color screen of usefulness is TFT LCD or CSTN LCD usually.TFT dichroic liquid crystal display and CSTN LCD respectively have relative merits.The TFT colour liquid crystal display device is well received by consumers with its outstanding image quality and response speed, but expensive price and huge power consumption also make many consumers hang back.Though CSTN LCD image quality and response speed are poorer than the TFT LCD, it is cheap, power consumption is less, if improve the image quality of CSTN LCD, will make the CSTN LCD become the very strong competitor of TFT LCD.
The image quality of LCD depends primarily on colourity (being saturation degree), brightness, contrast and the resolution of color, wherein the color of the light launched by the red, green, blue pixel of the color rendering scope of colour liquid crystal display device decides, each pixel is respectively (XR at the chroma point of CIE-XYZ colorimetric system, YR), (XG, YG), (XB, YB) time, the leg-of-mutton cartographic represenation of area that the color rendering scope surrounds with these three points on the x-y chromatic diagram.That is to say that this leg-of-mutton area is big more, can reproduce distinct colour element more.Normally with the three primary colors-red (0.67 of NTSC (NTSC) specified standard form, 0.33), green (0.21,0.71) and blue (0.14,0.08) 3 formed triangles are the basis, to represent described leg-of-mutton area than (% of unit is designated hereinafter simply as " NTSC ratio ") with respect to this leg-of-mutton area.The NTSC of TFT LCD is higher than 45% than generally, and the colourity NTSC ratio of CSTN LCD is about 30% usually, and image quality is more far short of what is expected than TFT LCD.Through research, with backlight (Backlight), liquid crystal (Liquid Crystal) and polaroid (Polarizer) and their matching structure, promptly the Yan look of the light that sends from LCD is compared by the NTSC of emission wavelength backlight, three kinds of pixels of colored filter red, green, blue and the retardation and the offset of the optical system that liquid crystal and polaroid are formed are determined the colourity NTSC that finds LCD than the colored filter that is decided by to have three kinds of pixels of red, green, blue (Color Filter), transillumination.Experiment showed, under the identical situation of other condition that if the colourity NTSC of the used colored filter of CSTN LCD is big than more, the NTSC of the shown Yan look of this CSTN LCD is than just big more so through a large amount of production.But in order to improve the NTSC ratio of colored filter, again following problem can appear: the NTSC ratio that 1) improves colored filter, the color saturation that is colored filter is higher, just need to increase thickness, this just needs a large amount of pigment, because the original just not sharp-pointed characteristic of the curve of spectrum of pigment, increase pigment, being equivalent to also can increase the absorption of main light emission portion, thereby the transmitance of main light emission portion is reduced, and causes pixel to shade on the whole.2) concentration that increases pigment in each pixel of colored filter causes the performance of photoetching material to descend, for example cause development time elongated, to the control of the pattern form problem that difficulty and quality descend that becomes.3) owing to increase the thickness of colored filter, be easy to generate the situation of the manufacturing process that is not suitable for LCD, and then increased the manufacturing cost of LCD.4) even adopt NTSC,, still can not obtain NTSC than higher CSTN LCD if do not have backlight, liquid crystal and the polaroid of coupling than high colored filter.For example adopt NTSC than greater than 65% colored filter, if there not be the backlight of coupling, the NTSC of CSTN LCD can reach 40% than the highest, still not as good as the TFT LCD.
[summary of the invention]
Fundamental purpose of the present invention is exactly in order to solve prior art problems, and a kind of CSTN LCD of high chroma and the method for realization high chroma thereof are provided, and improves the NTSC ratio of CSTN LCD, thereby improves the image quality of CSTN LCD.
Secondary objective of the present invention is exactly in order to solve prior art problems, and a kind of CSTN LCD of high chroma and the method for realization high chroma thereof are provided, and the NTSC that makes the CSTN LCD can match in excellence or beauty it with the TFT LCD than greater than 45%.
For achieving the above object, the CSTN LCD of a kind of high chroma that the present invention proposes, comprise first transparency carrier, second transparency carrier of facing with first transparency carrier, be sealed in the liquid crystal between first transparency carrier and second transparency carrier, colored filter, polaroid and backlight up and down, described colored filter is attached to the medial surface of first transparency carrier or second transparency carrier, described upper polarizer is attached to the lateral surface of first transparency carrier, described polaroid down is attached to the lateral surface of second transparency carrier, described backlight is positioned at the lateral surface of polaroid down, the colourity NTSC ratio of described colored filter is more than or equal to 60%, have two main light emission wavelength peaks in the light wave that described backlight sends, and the first main light emission wavelength peak position is in the blue light wavelength scope, and the second main light emission wavelength peak position is in the wavelength coverage of the intermediate light of ruddiness and green glow.
Preferably, the colourity NTSC of described colored filter ratio is 65%.The second main light emission wavelength peak position is the gold-tinted zone of 530nm~610nm in wavelength coverage.
Further improvement of the present invention is: the determined retardation of the composition proportion of described liquid crystal and up and down the offset of polaroid make the first main light emission wavelength peak of backlight at the wavelength place of the blue pixel of colored filter, the second main light emission wavelength peak is at the wavelength place at the line center of the red pixel wavelength of colored filter and green pixel wavelength.
For achieving the above object, the CSTN LCD of the present invention's proposition realizes that the method for high chroma may further comprise the steps:
The colourity NTSC ratio that makes colored filter is more than or equal to 60%;
Have two main light emission wavelength peaks in the light wave that backlight is sent, and the first main light emission wavelength peak position is in the blue light wavelength scope, the second main light emission wavelength peak position is in the wavelength coverage of the intermediate light of ruddiness and green glow.
Preferably, the colourity NTSC of described colored filter ratio is 65%.The second main light emission wavelength peak position is the gold-tinted zone of centre of the red-green glow of 530nm~610nm in wavelength coverage.
Further improvement of the present invention is: also comprise optical wavelength peak match regulating step, described optical wavelength peak match regulating step comprise the retardation of regulating liquid crystal and up and down the offset of polaroid make the first main light emission wavelength peak of backlight at the wavelength place of the blue pixel of colored filter, the second main light emission wavelength peak is at the wavelength place at the line center of the red pixel wavelength of colored filter and green pixel wavelength.
The white light that sends backlight is made up of red, orange, yellow, green, blue, blue, purple, and have only three kinds of colors of red, green, blue on the colored filter usually, when the white light that sends backlight passes through three kinds of pixels of red, green, blue of colored filter respectively, have only ruddiness, green glow, blue light to pass through respectively, other light is absorbed fully.Realize redness, green, the blue demonstration of high color purity, then require the purity of ruddiness composition, green glow composition and blue light ingredient of the light that sends backlight the highest, have two main light emission wavelength peaks in the light wave that sends backlight of the present invention, realize that backlight to have two main light emission wavelength peaks be mature technology, one at two main light emission wavelength peaks of backlight of the present invention are at blue region, can realize that the purity of blue light ingredient is the highest by the blue pixel of colored filter.And another is arranged according to wavelength of visible light in the wavelength coverage of the intermediate light of red and green light, the only orange or yellow of the centre of ruddiness and green glow, among the present invention the light of the centre of ruddiness and green glow preferably with the crossing gold-tinted of the wavelength coverage of ruddiness and green glow.Gold-tinted can resolve into ruddiness and green glow, respectively by the red pixel and the green pixel of colored filter, can realize that then the purity of ruddiness composition and green glow composition is high as far as possible.The colourity of colored filter is good more simultaneously, the attainable chromaticity range of CSTN LCD is just big more, but improve the NTSC ratio of colored filter, just need to increase thickness, the experiment proved that, the NTSC ratio is 65% to be that colored filter is not change attainable maximum color saturation under the ink thickness situation, improves color saturation again and just need correspondingly increase certain thickness.So adopting the NTSC ratio is 65% to be that colored filter both can not increase thickness, the adjusting at the luminous predominant wavelength peak by backlight can improve the NTSC ratio of CSTN LCD again.By the retardation of adjusting liquid crystal and the offset of polaroid, can make the first main light emission wavelength peak of backlight at the wavelength place of the blue pixel of colored filter, the second main light emission wavelength peak is at the wavelength place at the line center of the red pixel wavelength of colored filter and green pixel wavelength, in this case, the NTSC ratio of CSTN LCD can reach 45%, compare quite with the NTSC of TFT LCD, improved the image quality of CSTN LCD greatly.
Feature of the present invention and advantage will be elaborated in conjunction with the accompanying drawings by embodiment.
[description of drawings]
Fig. 1 is a kind of structural drawing of CSTN LCD;
Fig. 2 is the branch distribution curve flux of the colored filter of a kind of embodiment of the present invention;
Fig. 3 is the wavelength luminosity curve figure of the backlight of a kind of embodiment of the present invention;
Fig. 4 is the synoptic diagram that the colored filter of a kind of embodiment of the present invention divides light curve and backlight luminosity curve coupling.
[embodiment]
Specific embodiment one, as shown in Figure 1, the CSTN LCD comprises following structure by surround lighting to backlight usually successively: upper polarizer 1, first transparency carrier 2, transparency electrode 3, liquid crystal 4, transparency electrode 5, colored filter 6, second transparency carrier 7, polaroid 8 and backlight 9 down.First transparency carrier 2 and second transparency carrier 7 adopt transparent glass substrate usually, are pasted with upper polarizer 1 and following polaroid 8 respectively in its outside.Transparency electrode is the ITO electrode normally.
Colored filter 6 is objects of the trickle pixel of red, green, blue with regular pattern that forms on transparency carriers such as glass by decoration method, electrochemical plating, print process, pigment dispersing method etc., be formed with the black matrix" (BM) of shading between the trickle pixel of red, green, blue, in case leak-stopping light improves image quality.Colored filter (Color Filter) red, green, the chroma point of the CIE-XYZ colorimetric system of blue pixel is respectively (XR, YR), (XG, YG), (XB, YB) time, the leg-of-mutton area that three points of on the x-y chromatic diagram this surround is with respect to the three primary colors-red (0.67 of NTSC (NTSC) specified standard form, 0.33), green (0.21,0.71) and blue (0.14,0.08) ratio of 3 formed triangle areas is more than or equal to 60%, be preferably more than or equal 65%, the NTSC ratio can be made as 65%, be that colored filter 6 adopts NTSC than the colored filter that is 65%, also can adopt NTSC to compare colored filter greater than 65% or 70%.Different NTSC is than realizing by thickness that improves RGB printing ink or the material that improves printing ink, high chroma colored filter as Taiwan rhenium treasured is to realize by improving thickness, and the high chroma colored filter in Japanese light village is realized by improving ink material.The optical wavelength figure of red, green, blue three looks of colored filter 6 as shown in Figure 2, the wavelength coverage of ruddiness is 610-700nm, the wavelength coverage of green glow is 500-530nm, the wavelength coverage of blue light is 400-480nm.
Backlight 9 is a kind of multilayer shape area source, is configured in the back of LCDs, as the back side light source of full-transparency type and transflective type liquid crystal display.Backlight 9 generally includes transparent light guide plate, is installed in the linear light source of light guide plate one end, surrounds reflective mirror and some functional layers of linear light source substantially.Linear light source uses cathode-ray tube (CRT) usually, by adjusting the proportioning of each fluorophor in the light source, can send the light of different colours.The wavelength coverage of ruddiness is 610-700nm, and the wavelength coverage of green glow is 500-530nm, and the wavelength coverage of blue light is 400-480nm, and the wavelength coverage of gold-tinted is 530-610nm.Be the light that improves backlight transmittance by colored filter, backlight in the present embodiment has two main light emission wavelength peaks, adjust the proportioning of fluorophor, make first emission wavelength peak be positioned at wavelength (400-480nm) scope of blue light, make second emission wavelength peak be positioned at the wavelength of gold-tinted (530-610nm) scope, as shown in Figure 3.Thereby what blue light is not had substantially absorb on the blue pixel of colored filter sees through, and is all absorbed on red, green pixel, and the excitation of the blue light of Xian Shiing is best like this.Yellow wavelengths can be decomposed into ruddiness composition and green glow composition between ruddiness and green wavelength, ruddiness composition does not wherein have seeing through of absorbing substantially on the red pixel of colored filter, and is all absorbed on green, blue pixel.And the green glow composition does not have seeing through of absorbing substantially on the green pixel of colored filter, and is all absorbed on red, blue pixel.Though like this for red, green glow separately, its excitation be not best, red, green glow is comprehensive, excitation is best.The general anti-and precious bright existing production of such backlight.
When the wavelength of the red, green, blue pixel of colored filter just in time with two wavelength peak matches of backlight, a wavelength peak is at the blue pixel wavelength of colored filter place, another wavelength peak position is in the central wavelength of red pixel wavelength of colored filter and green pixel wavelength line, as shown in Figure 4, the composition maximum that sees through of ruddiness, green glow and blue light in this case, the excitation that just can realize redgreenblue is best, and the excitation of whole C stn liquid crystal display is best.
Specific embodiment two, different with specific embodiment one be the optical system (Optical System) that the present embodiment design has liquid crystal (LiquidCrystal) and polaroid (Polarizer) composition, above-mentioned colored filter (Color Filter) and backlight (Backlight) are complementary, realize that the excitation of light of each pixel is the highest.
Birefringent phenomenon can take place during by liquid crystal in light, the light of different wave length by the time can produce certain retardation, by regulating the composition proportion of liquid crystal, can change retardation.Be attached with compensate film on the polaroid up and down.By the retardation of adjusting liquid crystal and the offset of polaroid compensate film, the light that sends backlight is changed at each wavelength, be equivalent to make emission wavelength peak curve backlight to produce slight moving, to regulate the wavelength of emission wavelength peak-to-peak value correspondence, the wavelength corresponding with three kinds of pixels of red, green, blue of colored filter is the most approaching, as shown in Figure 4, can realize ruddiness, green glow, the blue light of high color purity.Retardation and offset will be decided on the wavelength of three kinds of pixel correspondences of colored filter and emission wavelength peak curve backlight, empirical value examination by the long-term production gained is irritated, the liquid crystal retardation amount is between 800-860nm, the polaroid offset is 430nm up and down, regulate the polaroid angle and reach optimal display result, add that backlight makes module, measure full frame redness with YC tester BM-7 or Other Instruments then, green, the chromaticity coordinate value of blue picture, corresponding triangle draws in the cie color coordinate axis, three primary colors-red (0.67 with NTSC (NTSC) specified standard form, 0.33), green (0.21,0.71) and blue (0.14,0.08) 3 formed standard triangles compare.If leg-of-mutton shape is on one side blue with respect to standard gable deflection, then need suitably reduce the retardation of liquid crystal or the offset of increase polaroid; On one side red as the fruit part deflection, as then to need suitably to increase the retardation of liquid crystal or reduce polaroid offset, similar to realize leg-of-mutton shape to the standard triangle, reach maximum area.Thereby the optical system that the compensate film that makes the retardation of liquid crystal and polaroid is formed makes the red of colored filter, green, the wavelength of blue pixel just in time reaches the coupling of the best with two predominant wavelength peaks of backlight, a wavelength peak is at the blue pixel wavelength of colored filter place, another wavelength peak position is in red pixel wavelength of colored filter and green pixel wavelengths centered place, realize that the light that backlight sends passes through red pixel respectively, when green pixel and blue pixel, the light of this pixel wavelength all almost completely by and the light of other pixel almost completely is absorbed, thereby the excitation that realizes each pixel light is the highest, compares greater than 45% with the NTSC that reaches the CSTN LCD.