JPS60163018A - Color liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain a display of a high luminance, a high contrast and a high picture quality by constituting a liquid crystal display element of a specified two layer structure which has added plural dichroic coloring matter mixtures being in a relation of a complementary color, to a separate liquid crystal, respectively. CONSTITUTION:Through a conductive through-hole 4 of an intermediate glass substrate 2, picture element electrode groups 12, 22 connected electrically so as to correspond to 1-to-1 are provided on both faces of the substrate 2, respectively, and on both sides of the substrate 2 containing the electrodes 12, 22, one of those which are obtained by dividing a constituent of a dichroic coloring matter mixture into two is added to a liquid crystal layer 13 in one side, and a constituent of the other coloring matter mixture is added to the other liquid crystal layer 23. Subsequently, common electrode layers 14, 15 connected to these two liquid crystal layers 13, 23 are provided on one surface, the two liquid crystal layers 13, 23 are covered with two transparent glass substrates 1, 3, provided so as to correspond to 1-to-1 to the picture element electrodes 12, 22 on a substrate 1, and a color film of plural colors for making an incident light transmit through selectively as a spectrum is provided. Also, two colors of two groups being a constituent of the dichroic coloring matter mixture are set to a complementary color relation. According to such a constitution, a large capacity display of a high luminance, a high contrast and a high picture quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a liquid crystal display element that is capable of high-brightness, high-contrast color display and has a large capacity display capacity.

(Prior Art) Display devices for displaying graphics and characters account for 1% of the total cost, and are used as display devices in office automation and various computer systems. For these display devices, there is an extremely strong demand for multi-color display and larger display capacity. So far, we have developed a display device that can meet these demands.

CRTs are commonly used. However, Cl-4T has many drawbacks, such as the device volume is large and hx, and the flickering of the screen eliminates eye strain.The emergence of a new type of thin display panel that does not have these drawbacks. I'm eager.

Plasma display panels (FDP) and electroluminescence (EL) have been developed for this purpose.
) panels, liquid crystal display (LCD) panels, etc., but the performance of these panels is extremely inadequate, and the situation is extremely unsatisfactory, especially when it comes to multicolor display. Among these new types of thin display panels, LCD is considered the most likely to replace RT.For example, regarding conventional LCD technology, see Tadashi Matsumoto
1. I am familiar with ``Latest Technology of Liquid Crystals'' (published by Kogyo Chogakai), co-authored by Ichiyoshi Kakuda. The large display capacity of LCD is realized by multiplying each display pixel with a switching element, and the L switching element is a polycrystalline s1. Amorphous Si, Te
Thin film transistors (TF'T) and the like are being used. In addition, as for the display coloring method, the background board is painted in all colors9.
Methods such as separating the pixels or attaching a color filter to each display pixel are used. That is, the liquid crystal layer operates as a light shutter in twisted nematic (TN) mode or black guest host (G) mode, and the color of the background plate or color filter is visible in the display pixels where the liquid crystal layer is on. This is why the display pixels of the liquid crystal 1m in the off state appear black. However, such a system has a dark display surface and is impractical in a reflective display, so it has to be used as a transmissive display. Even when used as a transmissive display, the current situation is that it is still insufficient in terms of achieving both high brightness and high contrast. In other words, when using the 5TN mode, the contrast is relatively good, but the brightness is insufficient. In the case of TN mode, it is necessary to insert two linear polarizing plates.9. This is because the light utilization rate of the light source typically drops to about 35%.

However, when using the GH mode, the brightness is better than when using the dTN mode, but the contrast generally deteriorates considerably. The main reason for this is that the dichroic ratio of the dichroic color scheme used in the GH mode is not sufficiently large. G
There are several methods for H mode, such as 2IIIi
The method called GH mode is 1C' and the brightness must be 1.
The contrast can be increased to a certain degree without reducing the contrast (r).The 21II type GH mode has a structure in which two nematic liquid crystal GH cells aligned in parallel are aligned so that their alignment directions are opposite to each other. Therefore, by using two cells with the above-mentioned layered switching element structure in each display pixel of the G GH nacelle, a display element with a high contrast that can display a large capacity and maintain high brightness can be obtained. You will get n.

However, in the case of a structure in which two cells are simply overlapped while 70≧.

A depth is created between the 21@ pixels that should be l, and when the display lfi is viewed from the diagonal direction, a pixel gap n occurs, resulting in a decrease in image quality. Even more problematic is the manufacturing cost, which is simply twice that of a normal LCD. In the case of an LCD in which switching elements are fully laminated on the buttock, even in a normal one-layer structure, high cost is a problem, and two-layer structure cells of switching element laminated LCDs are impractical in terms of cost and have been unsuccessful. Furthermore, even with a two-layer GH nacelle, it is currently difficult to obtain sufficient optical contrast. The main reason for this is, as mentioned above, the dichroic color complex.
The problem is that the color ratio is not large enough.

In particular, the black dichroic pigment required for the black GH mode, which operates as a single-light shutter, cannot be produced using a single pigment material; for example, three types of pigment materials, red, blue, and yellow, may be used as constituent components. A dichroic dye mixture is used. In this case, the blue dichroic pigment has a relatively large dichroic ratio, but the dichroic ratio of the red and yellow dichroic pigments is opaque, and as a result, as a black dichroic pigment mixture, it is not light. This results in the inconvenience that a sufficient two-color ratio cannot be obtained. 'Jt, single 6
- Even if a dichroic dye rarely has a component with a relatively good dichroic ratio, it has poor compatibility with other component color charts, making it difficult to dissolve the necessary amount when adding it to a liquid crystal as a dichroic dye mixture. There are many cases where this is not possible. In other words, 1. For example, even if a dichroic dye alone can dissolve 1% in a finished product, if it is dissolved in a liquid crystal, it will have 0.
．． At about 7%, there are many cases where only a little more than 1% of both are dissolved.

In this way, when using a dichroic dye mixture consisting of 1% and Enoki's number of components, there are many disadvantages to obtaining high contrast5.For example, with a black GH cell, sufficient contrast cannot be obtained. is rare under the current circumstances. Therefore, it has not been possible to obtain a liquid crystal cell with sufficient performance as a shutter, and conventional color liquid crystal display devices often have the drawback of not being able to provide high-brightness, high-contrast color display.

(Object of the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks and provide a color liquid crystal display element capable of high-brightness, high-contrast, high-quality color display.

(Structure of the Invention) The color liquid crystal display element of the present invention is arranged in accordance with one pixel.
A transparent intermediate glass substrate having conductive through-holes arranged on both sides of the intermediate glass substrate corresponding to each pixel is electrically connected in a l-to-l manner through the n# conductive through-holes. a group of pixel electrode pairs, one switching element connected to each of the pixel electrode pairs for controlling a potential applied to the pixel electrode pairs, and the intermediate glass substrate including the pixel electrodes. There are 10,000 holes on each surface.

And the constituent components of the dichroic color mixture are divided into two groups.

a liquid crystal layer to which one of the ten thousand sets of constituent components is added, and a dichroic dye mixture provided on the other surface of the intermediate glass substrate including the pixel electrode; It has a liquid crystal layer to which the other set of constituents is added, and a common electrode layer connected to the two liquid crystal layers on one side, and the liquid crystal layer 52 is connected from the outside of the two liquid crystal layers. A pair of transparent glass substrates, and 10,000 glass substrates are provided on either side of the two glass substrates in an l-to-l correspondence with the pixel electrodes to selectively transmit spectrally the n1 incident light. Here, if the two sets of dichroic pigments that make up the dichroic pigment mixture are complementary colors to each other, If you get a result, you can do it.

(Example) Next, five embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of one embodiment of the invention.

In FIG. 1, numerals 1, 2, and 3 are glass substrates constituting a two-layer OH liquid crystal display panel.
(in 0xide) 7 formed gr+, 1 of the pixel electrode 12
#υ and one group of pixel electrodes 22 are formed. These pixel electrodes are electrically connected one to one through through holes 4 formed in the intermediate glass substrate 2 to form a pixel electrode pair. Also.

Each pixel pole pair VC is provided with one switching element. In this embodiment, the switching element is amorphous silicon IFT;
It is configured as follows. 5 is M. Gate electric a,
6uSi, N, insulating film, 7 is an amorphous silicon layer,
8 is MO drain-pole, 9 is M. with a ground electrode. The ground electrode is connected to a pair of pixel electrodes formed by pixel electrodes 12 and 22. The TPT was also covered with an 81aN4 protective film 10. 13 and 23 are liquid crystal layers added to a black dichroic dye mixture (manufactured by Luz Co., Ltd.). That is, the liquid crystal layer 13 has rE43jK0.40X (
The liquid crystal layer added with DrG206J' is glazed and the liquid crystal 11i
i23 is [, i3J with 0.99% ND504'f
This is a liquid crystal layer containing r.

Common electrodes 14 and 15 are formed on the entire surface of the glass substrates 1.3 on both sides, and are electrically connected to the outside. For example, the color filter 11 corresponds l:1 to the pixel electrode pair consisting of the pixel electrodes 12 and 22.Here, the color filter 11 selectively transmits green light. death,
The color filter 21 selects red light.

Are the color filters 112 and 21 made of polyether sulfon resin? A mixture of Sumikalon E-40LJ and dye [Eastman Scarlet BQJ] was formed by staining with Eastman Scarlet BQJ. 2. The surface of each n substrate in contact with the liquid crystal is subjected to a normal parallel alignment process, but it is omitted in Figure i1 because it would be too complicated. The direction of the parallel alignment process is 2 in FIG. 1, which is the vertical direction of the circle on the paper for both sides of the liquid crystal 1Ii 130, and the direction perpendicular to the plane of the paper for both sides of the liquid crystal #23. In addition, the three glass substrates 1, 2 and 3 shown in Fig. 1 are adhesively fixed around the periphery with an adhesive containing spacer particles.
1 liquid constant layer 13? and 23 are both kept at about 10 μm by the effect of the spacer particles.

Next, the operation of this embodiment will be explained.

Both common electrodes 14 and 15 are kept at a potential of O■.

A full voltage of 25V or 0V is applied to the drain N-pole 8 depending on the image. Next, a pulse voltage of 30 V is periodically applied to the gate electrode 5, and the amorphous silicon TPT is turned on only while the voltage pulse is applied.
When a voltage of 25 V is applied to the drain pole 6, the pixel electrode 12j? and 22 to 2
A potential of 5V is generated, connecting the common electrode 14 and the pixel "1" to the pole 12.
A potential difference of 25 V is generated between the common electrode 15 and the pixel electrode 22 and between the common electrode 15 and the pixel electrode 22, respectively. As a result, the liquid crystal portions corresponding to the pixel '1 poles 122 and 22 are in the "on state". - Even if the amorphous 7 recon TPT is in the on state, if the voltage applied to the drain electrode is O There is no potential difference between n and tL.
The product will be in the "off state".

In this way, it is possible to create an "on state" and an "off state" of the liquid crystal depending on the image.

Up until now, we have described the period while the pulse voltage is being applied to the gate '1i pole V, but the potential difference between the 5th pixel electrode and the common electrode is also until the pulse voltage is applied at the 5th cycle. Amorphous silicon TPTp! Since the number of times of the discharging circuit formed by the liquid crystal and the liquid crystal is sufficiently large, the "on state" (p and "off state") of the liquid crystal is not maintained.

That is, by time-sharing the gate electrode array 2 and applying the image 1g to the drain electrode array in parallel to the gate electrode array 2 and the drain, a large-capacity dot matrix is displayed. is possible in the "off state" of the liquid crystal.

Liquid crystal molecule 2 of liquid crystal 11f 23 and liquid crystal l according to the
Dichroic dye 1'-ND50j containing lI2:llC is oriented in a direction perpendicular to the plane of the paper and absorbs linearly polarized light having a plane of polarization in this direction.

FIG. 2 is a characteristic curve diagram showing the absorption spectrum of the dichroic dye used in the example shown in FIG.

In Figure 2, curves 31 and 32 indicate the absorption spectra of dichroic dyes ND50J and rG206j, and curve 33 indicates the composite absorption spectrum of curves 31 and 32.The liquid crystal shown in Figure 1 The dichroic dye “G” contained in Iil#13
206'' is oriented vertically in the plane of the paper and absorbs linearly polarized light having a polarization plane in this direction. In this way, when the liquid crystal is in the OFF state, the two directly polarized components of the incident light are absorbed by the absorption spectra of curves 31 and 3.
L, as shown by a curve 33, which is a composite of 2, absorbs almost all wavelengths τ in the visible range. As a result, the pixel electrode pair region where the liquid crystal is in the "off state" appears almost entirely black. This is rU206
This is because the hues of J and "D50" are complementary to each other. -10,000, In the "on state" of the liquid crystal, the liquid crystal 1-
Both of the dichroic dyes added in 13 and 23 are oriented in a direction substantially perpendicular to the pixel electrode surface, and almost no longer absorb incident light. Therefore, the incident light is e.g. pixel electrode pair 122 and 2.
In the region 2, the light passes through the liquid crystal 1-, undergoes wavelength selection by the color filter 11, and is emitted as green light. Thus, a region of 1ffll cumulative electrode pairs in which the liquid crystal is in the "on" state Vc appears in colors selected by color filters arranged corresponding to that region.

In this way, a color display was realized. In the non-example color liquid crystal display element, when illuminated from behind with a fluorescent lamp having a brightness of 1500, a pixel in the 1-on state has a luminance of 450 nits. A pixel in the "off state" had a brightness of 28 nits. In other words, the color liquid crystal display element of the non-example is capable of displaying at a high brightness of 450 nits and a high contrast of 16:1, and because the intermediate glass substrate 2 is extremely thin with a thickness of approximately 0.1 mm. Even when the display surface is viewed from an oblique angle, the pixel electrode pairs do not appear out of alignment, and an extremely high-quality display can be obtained. Furthermore, the manufacturing process for the switching elements, which accounts for most of the cost in a display element in which all switching elements are stacked, has a structure in which one switching element slides a pair of pixel electrodes, so the switching elements are stacked on two sides of the substrate. There is no need to attach the switching element to the display element, and the structure is almost the same as that of the conventional switching element stacked display element, so it can be manufactured at low cost.

In addition, next to the comparison, dichroic color [G206J2 and [N
When both D50J and liquid crystal E43J were mixed at the same ratio of 0.40:0199 as in the example, the combined value of both was 1.IN, that is, [G206J was 0.
．． 32X, rND50J is 0.78Xl, is a commonly understood cutter.

In the conventional 01-layer structure GH cell using this dichroic color mixed sweet liquid crystal, the shape of the absorption spectrum is the same as that of track @33 in Figure 2, and although it is rare, the absorption rate is relatively reduced. , the contrast was 10:IL, and did not improve.

In the above embodiment, a case was described in which two types of dichroic dyes having a complementary color relationship were added to separate liquid crystals, but for example, a dichroic dye mixture consisting of five components was added to two
There are many examples of high-brightness and high-brightness VC and liquid crystal displays, including cases in which two sets of components and three components are added to separate liquid crystals to form a two-layer guest-host type liquid crystal display. It has been confirmed that a high-contrast, high-quality display can be obtained.
Ta.

(Effect of the invention) As explained in detail above, there is no invention.

A color liquid crystal display element capable of displaying a human figure with high brightness, high contrast, and high image quality is obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the invention, and FIG. 2 is a temporal curve diagram showing the absorption spectrum of the dichroic dye used in the embodiment shown in FIG. 1.2.3...Glass substrate, 4...Through hole, 5...Gate electrode, 6...
・Insulating film, 7...Amorphous silicon layer, 8
...Drain electrode, 9...Source electrode, 10...8 i, N4 protective film, 11...
... Color filter, 12 ... Pixel electrode, 13
...Liquid crystal layer, 14.15...Common electrode, 21...Color filter, 22...
Pixel 'pixel', 23...Liquid crystal layer, 31...
・Absorption spectrum of dichroic dye [ND50J. 32... Absorption spectrum of dichroic dye rG206J, 33... Synthetic absorption spectrum. 17- Figure 1≠ao kθθ 677ρ SirjL table (7th Figure Z

Claims (2)

[Claims] (1) A transparent intermediate glass substrate having conductive through holes arranged corresponding to the pixels, and conductive through holes arranged corresponding to the pixels on both sides of the intermediate glass substrate. a group of pixel electrode pairs electrically connected at lnl, and one pixel electrode connected to each of the pixel electrode pairs;
a switching element for controlling the voltage applied to one pole pair, and a dichroic dye mixture provided on the surface of the intermediate glass substrate including the pixel electrode; and a dichroic dye mixture. The components are divided into two groups, and one of the n or 10,000 groups of components is added to the liquid crystal layer and the pixel electrode is provided on the other surface of the intermediate glass substrate surface. A liquid crystal layer containing one set of constituents of the dichroic color mixture and a common electrode layer connected to each of the two liquid crystal layers on one side. , two transparent glass substrates from which the two crystal layers are exposed from the outside; & one of the two glass substrates is provided with an l-to-l correspondence with the pixel electrode on the surface of one of the ten thousand glass substrates; 1. A color liquid crystal display device comprising: a color film of a plurality of colors that spectrally selectively transmits incident light; (2) A color liquid crystal display element according to claim (1), wherein the two sets of dichroic dyes formed by all the constituent components of the dichroic dye mixture have complementary colors to each other.