JPH0358021A - Active matrix liquid crystal display element and projection type active matrix liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminate the need for polarizing plates and to allow the display of a high luminance and high contrast by specifying the refractive index anisotropy of a nematic liquid crystal and satisfying a specific relation between the average grain size, inter-electrode spacing and the max. impressed voltage. CONSTITUTION:A liquid crystal resin composite is packed between a substrate 2 and a counter electrode 6 and the refractive index anisotropy n of the nematic liquid crystal is specified to >=0.18. The following relation is satisfied when the average grain size of the liquid crystal is designated as Rmum, the spacing between both electrodes as dmum and the max. effective impressed volt age to be impressed to the liquid crystal resin composite as V: 0.3 < R. n < 0.7, 4R < d < 8R, 0.5R.V<d<R.V. Since the liquid crystal resin composite which can electrically control the scattering state and transmission state is used in such a manner, there is no need for the polarizing plates and the trans mittance at the time of transmission is greatly improved and, therefore, the display of the high luminance and high contrast is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active matrix liquid crystal display element and a projection type active matrix liquid crystal display device in which an active element is arranged for each pixel electrode.

[Prior Art] In recent years, liquid crystal displays have been widely used in personal word processors, handheld computers, pocket TVs, etc., taking advantage of their low power consumption, low voltage drive, and other features. Among them, active matrix liquid crystal display elements, in which an active element is arranged for each pixel electrode, are attracting attention and being actively developed.

Such liquid crystal display elements were initially developed using DSM (dynamic scattering).
A liquid crystal display element using a type of liquid crystal was also proposed, but
The SM type has the disadvantage of high current consumption due to the high current flowing through the liquid crystal, and currently, TN (twisted nematic) type liquid crystals are the mainstream and are appearing on the market as pocket TVs. TN-type liquid crystals have extremely low leakage current and low power consumption, so they are suitable for applications that use batteries as a power source.

[Problems to be Solved by the Invention] When an active matrix liquid crystal display element is used in DS mode, the leakage current of the liquid crystal itself is large. Therefore, a large storage capacitor must be provided in parallel with each pixel, which poses a problem in that the power consumption of the liquid crystal display element itself increases.

In the TN mode, the leakage current of the liquid crystal itself is extremely small, so there is no need to add a large storage capacity, and the power consumption of the liquid crystal display element itself can be reduced.

However, since the TN mode requires two polarizing plates, it has a problem of low light transmittance. In particular, when color display is performed using a color filter, only a few percent of the incident light can be used, requiring a strong light source, which results in an increase in power consumption.

Further, when projecting an image, an extremely strong light source is required, and there are problems in that it is difficult to obtain high contrast on the projection screen, and the heat generated by the light source affects the liquid crystal display element.

Therefore, in order to solve the problems of the TN mode, a mode has been proposed that uses a liquid crystal resin composite in which nematic liquid crystal is dispersed in a resin matrix and utilizes its scattering and transmission characteristics.

However, there was a problem in that sufficient brightness and contrast ratio could not be obtained at low voltage.

[Means for Solving the Problems] The present invention was made to solve the above-mentioned problems, and includes an active matrix substrate in which an active element is provided for each pixel electrode, a counter electrode substrate in which a counter electrode is provided, and During this process, a nematic liquid crystal with positive dielectric anisotropy is dispersed and held in a resin matrix, and the refractive index of the resin matrix is made to almost match the ordinary refractive index (n0) of the liquid crystal used. In an active matrix liquid crystal display element formed by sandwiching a body, the refractive index anisotropy Δn of the nematic liquid crystal used is 0.18 or more, and the average particle diameter R (μm) of the liquid crystal dispersed in the resin matrix, both Electrode gap d(μ
m), maximum effective applied voltage V applied to the liquid crystal resin composite
(V) is 0.3 < R- Δ n <
0.7 (1) 4R<d<8R
(2) 0.5R・V < d
<R-V An active matrix liquid crystal display element characterized by satisfying the relationship (3) and a resin used for the liquid crystal resin composite are photocurable vinyl resins, and the liquid crystal and the resin are An active matrix liquid crystal display element characterized by using a liquid crystal resin composite obtained by irradiating a solution in which a homogeneous solution of The present invention provides a projection type active matrix liquid crystal display device characterized by combining a light source and a projection optical system.

In the active matrix liquid crystal display element of the present invention, a liquid crystal resin composite whose scattering state and transmission state are electrically controlled is used as the liquid crystal material sandwiched between the active matrix substrate and the counter electrode substrate. , there is no need for a polarizing plate, and the transmittance of light during transmission can be greatly improved.

Therefore, a bright display is possible, and especially when used in a projection type display, a bright and high contrast projection type display can be obtained.

Furthermore, problems such as alignment treatment essential for TN-type liquid crystal display elements and destruction of active elements due to generated static electricity can be avoided, so that the manufacturing yield of liquid crystal display elements can be greatly improved.

Furthermore, since this liquid crystal resin composite is in the form of a film after curing, problems such as short circuits between substrates due to pressurization of the substrates and destruction of active elements due to movement of spacers are less likely to occur.

In addition, this liquid crystal resin composite has a resistivity equivalent to that of the conventional TN mode, and there is no need to provide a large storage capacitance for each pixel electrode as in the DS mode, making it easy to design active elements. Moreover, it is possible to keep the power consumption of the liquid crystal display element low. Therefore, production is easy because the alignment film forming process can be removed from the manufacturing process of conventional TN mode liquid crystal display elements.

The specific resistance of the liquid crystal resin composite is 5X 10”Ωc
m or more is preferred. Furthermore, in order to minimize the voltage drop due to leakage current, etc., it is more preferable that the voltage is 1010 Ωcm or more, and in this case, it is not necessary to provide a large storage capacitance for each pixel electrode.

Active elements provided in the pixel electrode include transistors, diodes, nonlinear resistance elements, etc., and two or more active elements may be arranged in each pixel as necessary. The liquid crystal resin composite is sandwiched between an active matrix substrate provided with such an active element and a pixel electrode connected thereto, and a counter electrode substrate provided with a counter electrode to form a liquid crystal display element.

The projection light source and projection optical system are conventionally known projection light sources,
A projection optical system such as a lens can be used, and usually the liquid crystal display element may be placed between the projection light source and the projection lens.

As a result, in the present invention, as a liquid crystal display element, an active matrix substrate in which an active element is provided for each pixel electrode,
A nematic liquid crystal with positive dielectric anisotropy is dispersed and held in a resin matrix between the counter electrode substrate provided with the counter electrode, and the refractive index of the resin matrix is approximately equal to the ordinary refractive index (n0) of the liquid crystal used. Since it uses a liquid crystal display element sandwiching a transparent-permeable liquid-crystal resin composite that is made to match, it has the advantage that brightness and high contrast can be easily obtained.

Specifically, in the present invention, as a liquid crystal display element, a liquid crystal resin composite consisting of a resin matrix with a large number of fine pores and nematic liquid crystal filled in the pores is used as an active matrix substrate and a counter electrode. The refractive index of the liquid crystal changes depending on the voltage applied between the electrodes held between the substrate and the resin matrix, and the relationship between the refractive index of the resin matrix and the liquid crystal changes, and the refractive index of both changes. A liquid crystal display element can be used that is in a transmitting state when the refractive indexes match, and is in a scattering state when the refractive indexes are different.

The liquid crystal resin composite consists of a resin matrix with many fine pores and liquid crystal filled in the pores.
It has a structure in which liquid crystal is sealed inside liquid bubbles like microcapsules, but individual microcapsules do not have to be completely independent; individual liquid crystal bubbles can fill pores like in a porous material. They may communicate through the

The liquid crystal resin composite used in the liquid crystal display element of the present invention is prepared by mixing a nematic liquid crystal and a material constituting the resin matrix to form a solution or latex, and then applying photocuring, thermosetting, and solvent treatment. The resin matrix may be separated by curing by removal, reaction curing, etc., and the nematic liquid crystals may be dispersed in the resin matrix.

It is preferable to use a photocuring or thermosetting resin as the resin used, since it can be cured in a closed system.

In particular, it is preferable to use a photocurable resin because it can be cured in a short time without being affected by heat.

The specific manufacturing method is to form a cell using a sealing material in the same way as conventional nematic liquid crystals, inject a mixture of uncured nematic liquid crystal and resin matrix through the injection port, and seal the injection port. After that, it can be cured by irradiation with light or by heating.

In the case of the liquid crystal display element of the present invention, a mixture of uncured nematic liquid crystal and a resin matrix is supplied onto a substrate provided with a transparent electrode as a counter electrode, for example, without using a sealing material, and then, It is also possible to stack active matrix substrates in which active elements are provided for each pixel electrode and harden them by irradiating light or the like.

Of course, after that, a sealing material may be applied to the periphery to seal the periphery. According to this manufacturing method, the mixture of uncured nematic liquid crystal and resin matrix can be simply supplied by roll coating, spin coating, printing, application with a dispenser, etc., so the injection process is simple and productivity is extremely high. .

In addition, the mixture of these uncured nematic liquid crystals and resin matrix may contain ceramic particles for substrate gap control, plastic particles, spacers such as glass fibers, pigments, dyes, viscosity modifiers, and other materials that may be used to improve the performance of the present invention. Additives may be added that do not have an adverse effect.

By curing this element with a sufficiently high voltage applied only to a specific part during the curing process, that part can always be in a light-transmitting state, so if there is something you want to display in a fixed manner, may form such a normally transparent portion.

The response time of a liquid crystal display element using such a liquid crystal resin composite of the present invention is that the rise of voltage application is 3 to 50 ms.
ec level, voltage removal fall 10-801lsec
This is about the same speed as that of conventional TN mode liquid crystal display elements.

In addition, its voltage-transmittance electro-optical characteristics are similar to that of conventional TN.
The mode is relatively gentler than that of a liquid crystal display element, and it is easier to drive for gradation display.

Note that the higher the transmittance of a liquid crystal display element using this liquid crystal resin composite in a transmission state, the better, and the haze value in a scattering state is preferably 80% or more.

In the present invention, while a voltage is applied, the refractive index of the resin matrix (after curing) is made to match the ordinary refractive index (n0) of the liquid crystal used.

As a result, when the refractive index of the resin matrix and the refractive index of the liquid crystal match, light is transmitted, and when they do not match, light is scattered (
cloudy). The scattering property of this element is higher than that of the conventional D
A display with a higher contrast ratio than that of an S-mode liquid crystal display element can be obtained.

An object of the present invention is to provide an optimal configuration of an active matrix liquid crystal display element using this liquid crystal resin composite.

That is, the present invention provides an active matrix liquid crystal display element that has high transmittance during transmission, high scattering property (light-shielding property) during scattering, and a high contrast ratio.

The factors that determine the electro-optical characteristics of an active matrix liquid crystal display element using the above liquid crystal resin composite include the refractive index (ordinary refractive index n0, extraordinary refractive index n.) of the liquid crystal used.
, relative dielectric constant (ε//, above ε, // and above indicate parallel and perpendicular to the liquid crystal molecule axis, respectively), viscosity, elastic constant, and refractive index n of the resin used. , relative dielectric constant ε, elastic modulus, and average particle diameter R of liquid crystal dispersed and held in the resin matrix.
, the volume distribution ratio Φ, the gap between both electrodes and substrates (thickness of the liquid crystal resin composite) d, and the maximum effective applied voltage V applied to the liquid crystal resin composite in the pixel portion by the active element. Here, the liquid crystal average particle diameter R refers to the diameter when the liquid crystal forms approximately spherical liquid bubbles, and when the liquid crystal has a porous interconnected structure, it refers to the area where the directors of the liquid crystal are correlated with each other. means the diameter of

The electro-optical properties of the active matrix liquid crystal display element using the liquid crystal resin composite of the present invention include high scattering properties in the absence of an electric field and high transparency when an electric field is applied, that is, a high display contrast ratio. It is desirable to have When projection-type display is performed using such a liquid crystal display element, a display with high brightness and high contrast ratio can be obtained.

In order to obtain such an indication, it is necessary that the above factors have an optimal relationship. Among these factors, a particularly important factor that determines the electro-optical characteristics of an active matrix liquid crystal display element is the refractive index of the liquid crystal used (refractive index anisotropy Δn = extraordinary light refractive index n; ordinary light refractive index n). >, the average particle diameter R of the liquid crystal, and the gap d between the two electrodes and substrates, which are optimized using the maximum effective voltage applied to the pixel.

The refractive index anisotropy Δn (=n.-n0) of the liquid crystal used is
In order to contribute to scattering properties in the absence of an electric field and to obtain high scattering properties, it is preferable that the value be larger than a certain level. Specifically, Δ
n>0. 18 is the preferred condition. Also, the ordinary refractive index n0 of the liquid crystal used is the refractive index n0 of the resin matrix.
, is preferable, and in this case, high transparency can be obtained when an electric field is applied. Specifically, nO−0.03<n
．． <n. It is preferable to satisfy the relationship of +0.05.

Average particle diameter R of liquid crystal dispersed and held in the resin matrix
is a very important factor, contributing to the scattering properties in the absence of an electric field and the operating characteristics of the liquid crystal when an electric field is applied. The scattering property in the absence of an electric field varies depending on the relationship between the refractive index anisotropy Δn of the liquid crystal used, the wavelength circle of the light, and the average particle diameter R of the liquid crystal, but in the visible light range, the scattering property per unit operating amount of liquid crystal changes. The scattering property becomes maximum when the average particle diameter R (μm) is 0.3 <
R-Δn<0.7
This is when the relationship (1) is satisfied. Within this range, the scattering property has little wavelength dependence, and strong scattering is obtained over the entire visible light range, so a display with a high contrast ratio can be obtained. If the average particle diameter R is smaller than the range of formula (1), the scattering property will have a wavelength dependence that is stronger on the short wavelength side, and a higher electric field will be required for the operation of the liquid crystal. There also arises the problem of increased power consumption. On the other hand, if the average particle diameter R is larger than the range expressed by equation (1), the wavelength dependence of the scattering property is small, but the scattering property becomes weak over the entire visible light range, the contrast ratio decreases, and the scattering occurs from the time of transmission. There is also the problem that responsiveness to time is slow. The electrode substrate gap d is also an important factor. Increasing d improves the scattering properties in the absence of an electric field. However, if d is too large, a high voltage will be required to achieve sufficient transparency when applying an electric field, resulting in increased power consumption and conventional TN
A problem arises in that active elements and driving ICs cannot be used. Furthermore, when d is made small, high transparency can be obtained at low voltage, but the scattering property in the absence of an electric field decreases. Therefore, in order to achieve both scattering properties when no electric field is applied and high transparency when an electric field is applied, d (μm) must satisfy 4R<d<8R (2), and when applied to the liquid crystal resin composite. The maximum effective applied voltage V (V) is 0.5R-V < d < R-V
It is necessary to satisfy the relationship (3). Within this range, display with a high contrast ratio is possible using conventional TN active elements and driving ICs.

The setting of d within the range of equation (2) can be appropriately set depending on the relationship between the relative permittivity anisotropy Δε (=ε↓−ε//) and the elastic constant of the liquid crystal used. Generally, it is preferable to use a liquid crystal with a large Δε (Δε>10) and to maximize d within a range such that sufficient transparency can be obtained at the maximum effective applied voltage.

As described above, in an active matrix liquid crystal display element using a liquid crystal resin composite that becomes transparent when a voltage is applied and becomes a scattering state when no electric field is applied, the formula (1). (2), (3)
A liquid crystal display element that satisfies all of the following conditions can provide a bright display with a high contrast ratio using conventional TN active elements and driving ICs. Specifically, display with a contrast ratio of 100 or more and a transmittance of 70% or more when an electric field is applied is possible. Furthermore, since the dynamic range is wide, an excellent element capable of displaying fine intermediate tones can be obtained.

In addition, in order to improve the scattering property in the absence of an electric field, it is effective to increase the volume fraction Φ of the operable liquid crystal in the liquid crystal resin composite, and it is preferable that Φ>20%, which has higher scattering property. It is preferable that Φ>35%. On the other hand, if Φ becomes too large, the structural stability of the liquid crystal resin composite deteriorates, so Φ<70% is preferable.

When no electric field is applied, the liquid crystal display element of the present invention exhibits a scattering state (that is, a cloudy state) due to the difference in refractive index between the unaligned liquid crystal and the resin matrix. Therefore, when used as a projection display device as in the present invention, light is scattered in areas without electrodes, and even if no light-shielding film is provided in areas other than pixel areas, the light will not reach the projection screen. , it looks black. This eliminates the need to shield parts other than the pixel electrode with a light-shielding film, etc. in order to prevent light leakage from parts other than the pixel electrode, and has the advantage of eliminating the need for the process of forming a light-shielding film. have

An electric field is then applied to the desired pixel. In the pixel area to which this electric field is applied, the liquid crystal is aligned, and the ordinary refractive index of the liquid crystal (
n. ) matches the refractive index (n, ) of the resin matrix, indicating a transmission state, and light is transmitted through the desired pixel, resulting in a bright display on the projection screen.

By curing this element while applying a sufficiently high voltage only to a specific part during the curing process, that part can always be in a light transmitting state.
If there is something that you want to display in a fixed manner, you may form such a normally transparent part.

Further, the active matrix liquid crystal display element of the present invention includes:
Color display can be performed by providing a color filter. These color filters may be provided in three colors on one liquid crystal display element, or one color filter may be provided on one liquid crystal display element.
You may provide different colors or combine three of these. This color? The filter may be provided on the electrode surface side of the substrate, or may be provided on the outside.

Furthermore, color display may be performed by mixing dyes, pigments, etc. into the liquid crystal resin composite.

FIG. 1 is a cross-sectional view of an active matrix liquid crystal display element of the present invention.

In FIG. 1, l is a liquid crystal display element, 2 is a substrate made of glass, plastic, etc. for an active matrix substrate,
3 is ITO' (IniOa-Sn02), SnO
pixel electrodes such as (2), 4 active elements such as transistors, diodes, non-linear resistance elements, 5 a substrate made of glass, plastic, etc. for the counter electrode substrate, 6 ITO. Sno
Counter electrodes such as w and 7 indicate a liquid crystal resin composite sandwiched between both substrates.

FIG. 2 is a schematic diagram of a projection type active matrix liquid crystal display device using the active matrix liquid crystal display element of FIG.

In FIG. 2, 1l is a projection light source, 2l is a liquid crystal display element, 13 is a projection optical system including lenses, apertures, etc.
Reference numeral 14 indicates a projection screen for projecting images. In this example, the projection optical system includes an aperture or spot 15, which is a plate with holes, a condensing lens l6, and a projection lens 17.

TPT (thin film transistor) as an active element of the present invention
When using a three-terminal element such as -M I M element,
When using a two-terminal element such as a PIN diode,
The counter electrode substrate is patterned into stripes.

Furthermore, when TPT is used as the active element, silicon is suitable as the semiconductor material. In particular, polycrystalline silicon is not as photosensitive as amorphous silicon, so
It is preferable that the light from the light source is not blocked by the light shielding film because malfunction does not occur. When this polycrystalline silicon is used as a projection type liquid crystal display device as in the present invention, a strong projection light source can be used and a bright display can be obtained.

Furthermore, in the case of conventional TN-type liquid crystal display elements, a light-shielding film is often formed between the pixels in order to prevent light leakage from between the pixels, and at the same time, a light-shielding film is also formed on the active element part at the same time. Forming a light shielding film on the active element portion does not significantly affect the overall process. That is, even if polycrystalline silicon is used as the active element and no light shielding film is formed in the active element portion, if it is necessary to form a light shielding film between pixels, the number of steps cannot be reduced.

In contrast, in the present invention, as mentioned above, a liquid crystal resin composite is used in which the refractive index of the resin matrix almost matches the ordinary refractive index (n0) of the liquid crystal used. Since light is scattered in areas where no voltage is applied and becomes black on the projection screen, there is no need to form a light-shielding film between the pixels. Therefore, when polycrystalline silicon is used as an active element, there is no need to form a light-shielding film on the active element, which eliminates the process of forming a light-shielding film, reducing the number of steps and improving productivity. will improve.

Further, the electrode is usually a transparent electrode, but when used as a reflective liquid crystal display device, it may be a reflective electrode made of chromium, aluminum, or the like.

In addition, the liquid crystal display element and liquid crystal display device of the present invention may be laminated with infrared cut filters, ultraviolet cut filters, etc., or printed with characters, figures, etc., or may use a plurality of liquid crystal display elements. You may also do so.

Furthermore, in the present invention, a protective plate such as a glass plate or a plastic plate may be laminated on the outside of this liquid crystal display element. This reduces the risk of damage even if the surface is pressurized, improving safety.

In the present invention, when a photocurable resin is used as the uncured resin constituting the liquid crystal resin composite described above, it is preferable to use a photocurable vinyl resin.

Specifically, photocurable acrylic resins are exemplified, and those containing acrylic oligomers that are polymerized and cured by light irradiation are particularly preferred.

The liquid crystal used in the present invention is a nematic liquid crystal having positive dielectric anisotropy, and is a liquid crystal in which the refractive index of the resin matrix matches the ordinary refractive index (n0) of the liquid crystal,
Although they may be used alone or in combination, it is more advantageous to use a composition in order to satisfy various required performances such as operating temperature range and operating voltage.

In addition, when a photocurable resin is used for the liquid crystal used in the liquid crystal resin composite, it is preferable to uniformly dissolve the photocurable resin, and the cured product after light exposure does not dissolve or is difficult to dissolve. When using a composition, it is desirable that the solubility of each liquid crystal be as close as possible.

When manufacturing a liquid crystal resin composite, the active matrix substrate and the counter electrode substrate are arranged so that the electrode surfaces face each other, and the periphery is sealed with a sealing material, and the injection port is closed. Alternatively, the injection port may be sealed by injecting an uncured liquid crystal mixture for the liquid crystal resin composite, or by supplying a mixture of the curable compound and liquid crystal onto the substrate and stacking the opposing substrates. It may also be manufactured by

In the liquid crystal display element of the present invention, a dichroic dye, a simple dye, or a pigment may be added to the liquid crystal, or a colored curable compound may be used.

In the present invention, by using liquid crystal as a solvent in the liquid crystal resin composite and curing the photocurable resin by exposure to light, there is no need to simply evaporate the solvent and water that are unnecessary during curing. Therefore, since it can be cured in a closed system, the conventional manufacturing method of injection into cells can be used as is, making it highly reliable.It also has the effect of bonding two substrates together with photocurable resin, making it even more reliable. becomes more sexual.

By using a liquid crystal resin composite in this way, there is a low risk of short circuiting between the upper and lower transparent electrodes, and there is no need to strictly control the orientation or substrate gap as with normal TN display elements, and the transparent It is possible to manufacture liquid crystal display elements with extremely high productivity by controlling the state and the scattering state.

When the substrate of this liquid crystal display element is made of plastic or thin glass, it is preferable to laminate a protective plate of plastic, glass, or the like on the outside for further protection.

In the liquid crystal display device of the present invention, when a voltage is applied for driving, the maximum effective voltage expressed by the above-mentioned formula (3) or less, usually the above-mentioned maximum effective voltage, is applied to the liquid crystal resin composite between the electrodes of the pixel. It suffices if it is driven so that the

Conventional projection light sources, projection optical systems, projection screens, etc. can be used as the projection light source, projection optical system, projection screen, etc., and the active matrix liquid crystal display element of the present invention is arranged between the projection light source and the projection optical system. do it. of course,
Images of a plurality of active matrix liquid crystal display elements may be combined and displayed using an optical system.

Further, a cooling system or a channel display such as an LED may be added to this.

In particular, when using this projection type display, display contrast can be increased by installing a device that reduces diffused light on the optical path, such as an aperture or spot as shown by l5 in Figure 2. .

In other words, a device that reduces diffused light extracts the light that travels straight to the incident light (the light that passes through the transparent portion of the pixel) out of the light that has passed through the liquid crystal display element, and reduces the light that does not travel straight (
Any material may be used as long as it reduces the amount of light scattered in the portion where the liquid crystal resin composite is in a scattering state. In particular, it is preferable that the light that travels straight is not reduced, and the light that does not travel straight is reduced as diffused light.

As shown in FIG. 2, the specific device is composed of a liquid crystal display element and a projection optical system, including a liquid crystal display element 12, a condensing lens 16, an aperture or spot 15 which is a plate with holes, and a projection lens. Some are equipped with l7. According to this example, among the light that comes out from the projection light source and passes through the liquid crystal display element l2, the light that travels straight with respect to the incident light is focused by the condenser lens 16, and the light that goes straight to the incident light is condensed by the condenser lens 16. and is projected through the projection lens l7. On the other hand, the light scattered by the liquid crystal display element 12 that does not travel straight does not pass through the aperture or the hole formed in the spot 15 even if it is focused by the condensing lens l6. Therefore, scattered light is not projected, improving the contrast ratio. As another example, instead of the aperture or the spot 15, a mirror having a small area may be placed obliquely at the same position, and the reflected light may be projected through a projection lens placed on its optical axis. Further, without using such a condensing lens, a spot, a mirror, etc. may be installed at a position where the light beam is focused by the projection lens. The ratio of the straight component to the scattered component that reaches the projection screen can be controlled by the diameter of the spot, mirror, etc., and focal length of the lens, and may be set so as to obtain desired display contrast and display brightness.

When using a device that reduces diffused light as shown in Figure 2, in order to increase the brightness of the display, it is preferable that the light incident on the liquid crystal display element from the projection light source be more parallel. A light source that is large and as close to a point light source as possible,
It is preferable to configure the projection light source by combining a concave mirror, a condenser lens, etc.

[Function] According to the present invention, a display with a high contrast ratio can be obtained,
When used in a projection type display, light passes through the transmission-scattering type liquid crystal display element and the projection screen displays brightly in the transmission state, and light is scattered in the scattering state, and the projection screen The display is dark, and a display with the desired high brightness and high contrast ratio can be obtained.

In particular, since the present invention has the above configuration, the maximum effective applied voltage V applied to the liquid crystal resin composite is
OV or less, and active elements and driving ICs such as those used in conventional TN type active matrix liquid crystal display elements can be easily used.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Chromium was deposited to a thickness of 60 nm on a glass substrate (7059 substrate manufactured by Corning) and patterned to form a gate electrode. Subsequently, a silicon oxynitride film and an amorphous silicon film were deposited using a plasma CVD apparatus. This was annealed using a laser and then buttered to form polycrystalline silicon. On this, lindove amorphous silicon and chromium were deposited using plasma CVD and evaporation equipment, respectively.
It was patterned to cover the polycrystalline silicon to form a first layer source electrode and drain electrode. Furthermore, ITO
After vapor-depositing, patterning was performed to form a pixel electrode.

Subsequently, chromium and aluminum were successively deposited and patterned to connect the pixel electrode and the first layer source electrode and drain electrode to form the second layer source electrode and drain electrode. Thereafter, a silicon oxynitride film was again deposited using a plasma CVD apparatus to serve as a protective film, and an active matrix substrate was created.

A counter electrode substrate made of the same glass substrate with ITO electrodes formed on its entire surface and the previously manufactured active matrix substrate were arranged so that the electrode surfaces faced each other, and a spacer with a diameter of about 11.0 μm was formed inside. After spraying, seal the surrounding area with epoxy sealant except for the injection port.
An empty cell with a substrate gap of 11.0 μm was manufactured.

6 parts of 2-ethylhexyl acrylate and 18 parts of hydroxyethyl acrylate, acrylic oligomer (rM-1200J manufactured by Toago Kagaku Co., Ltd., viscosity 300.0
00 cps/50° C.), 0.4 parts of Darocure-11164 manufactured by Merck Co., Ltd. as a photocuring initiator, and 62 parts of rE-8J manufactured by BDH Corporation as a liquid crystal were uniformly dissolved.

This mixture was injected from the injection port into the empty cell manufactured by the above method, and the injection port was sealed.

This was irradiated with ultraviolet rays for 30 seconds to cure the liquid crystal resin composite, thereby producing an active matrix liquid crystal display element.

The average particle diameter R of the liquid crystal in the liquid crystal resin composite of this liquid crystal display element is approximately 2.0 μm, and the refractive index anisotropy Δn of the liquid crystal is approximately 2.0 μm.
was approximately 0.24, and dielectric anisotropy Δε was approximately 15.6.

When this device was driven using a conventional drive IC for a TN type liquid crystal display device so that the voltage applied to the liquid crystal resin composite was an effective value of 7V, the linear light transmittance was Transmittance is approximately 80% at time, transmittance is approximately 0.5 at OV
%, and a display with a contrast ratio of about 160 was obtained when driven at 7V. Also, when this was driven with a video signal,
A moving image display with halftones and no afterimage was obtained.

For this liquid crystal display element, a projection light source and a projection optical system were combined to form a projection type liquid crystal display device. When this was used in the same way as in the previous case, the voltage applied to the liquid crystal resin composite was driven to an effective value of 7.degree., and a bright display with a high contrast ratio was obtained on the projection screen.

The contrast ratio of the image projected onto the projection screen is
It was about 60 when no device was used to reduce the diffused light.

On the other hand, when a spot as shown in Figure 2 was used as a device to reduce diffused light, the number was about 120. Furthermore, when driven by video signals, it was possible to display moving images on a large screen of 50 inches or more.

Comparative Example 1 Instead of the liquid crystal resin composite of Example 1, ordinary nematic liquid crystal was injected to produce a projection type active matrix liquid crystal display element as a TN type liquid crystal display element.

When this liquid crystal display element was used in combination with the projection light source and projection optical system of Example 1 to form a projection type liquid crystal display device and driven in the same manner as in Example 1, the display brightness on the projection screen was as follows. The contrast ratio was only about 20, which was about 1/3 as dark as in the previous case.

Examples 2 to 4, Comparative Examples 2 to 4 Active matrix liquid crystal display elements were manufactured in substantially the same manner as in Example 1 by varying the average particle diameter R of the liquid crystal and the substrate gap d.

Transmittance T of the liquid crystal display element when a voltage of 7V is applied
vv, the contrast ratio C R o due to the linear light transmittance of the liquid crystal display element itself, and the contrast ratio C R p when projected onto the projection screen when a spot as shown in Figure 2 is used as a device for reducing diffused light. It was measured.

The results are shown in Table 1.

Example 4 When the liquid crystal display element of Comparative Example 3 was driven at a driving voltage of IOV, Tsv was about 77% and CRfl was about 150.
, CRP was approximately 110.

[Effects of the Invention] In the active matrix liquid crystal display element of the present invention, the active matrix liquid crystal display element is sandwiched between the active matrix substrate and the counter electrode substrate. As the d-crystal material uses a liquid crystal display element sandwiching a liquid crystal resin composite that electrically controls the scattering state and transmission state, there is no need for a polarizing plate, and the transmittance of light during transmission is greatly increased. can be improved.

The liquid crystal display element of the present invention has high scattering properties when no electric field is applied, and high transmittance when an electric field is applied by an active element, and is suitable for driving conventional TN type liquid crystal display elements. Even when driven using an IC, display with a high contrast ratio and high brightness is possible.

Therefore, the liquid crystal display element of the present invention is particularly effective for projection-type display, and can provide a bright and high-contrast projection-type display. Furthermore, the light source can also be downsized.

Furthermore, since there is no need to use a polarizing plate, there is also the advantage that the wavelength dependence of the optical characteristics is small and color correction of the light source is almost unnecessary.

Furthermore, problems such as alignment treatment such as rubbing, which is essential for TN-type liquid crystal display elements, and destruction of active elements due to generation of static electricity associated therewith can be avoided, so that the manufacturing yield of liquid crystal display elements can be significantly improved.

Furthermore, since this liquid crystal resin composite is in the form of a film after curing, problems such as short circuits between substrates due to pressurization of the substrates and destruction of active elements due to movement of spacers are less likely to occur.

In addition, the specific resistance of this liquid crystal resin composite is the same as that of the conventional TN mode, and there is no need to provide a large storage capacitance for each pixel electrode as in the conventional DS mode, making it easy to design active elements. Therefore, it is possible to easily increase the ratio of the effective pixel electrode area and to keep the power consumption of the liquid crystal display element low.

Furthermore, production is easy because it can be manufactured by simply removing the alignment film forming process from the manufacturing process of conventional TN mode liquid crystal display elements.

Furthermore, a liquid crystal display element using this liquid crystal resin composite has a short response time, and can easily display moving images. Furthermore, since the electroluminescent characteristic (voltage-transmittance) of this liquid crystal display element is relatively gentle compared to that of a TN mode liquid crystal display element, it can be easily applied to gradation display.

In addition, in the liquid crystal display element of the present invention, since light is scattered in parts where no electric field is applied, there is no leakage of light during projection even if parts other than pixels are not shielded by a light shielding film, and the gap between adjacent pixels can be reduced. No need to block light. For this reason, in particular, by using an active element made of polycrystalline silicon as an active element, a high-brightness projection light source can be used without a light-shielding film on the active element part, and a high-brightness projection-type liquid crystal display device can be easily manufactured. Obtainable. Furthermore, in this case, there is no need to provide a light shielding film at all, which further simplifies the production process.

In addition to this, the present invention can be applied in various other ways as long as the effects of the present invention are not impaired.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the basic structure of an active matrix liquid crystal display element of the present invention. FIG. 2 is a schematic diagram showing the basic configuration of a projection type active matrix liquid crystal display device of the present invention. Liquid crystal display element: 1, 12 Substrate: 2, 5 Pixel electrode: 3 Active element: 4 Counter electrode: 6 Liquid crystal resin composite: 7 Projection light source = 11 Projection optical system: 13 Projection screen spot condenser lens Projection lens = 14 :l5 :l6 :17 16: Yuen Lens Il: Provisional Intoxication Person Proceedings Amendment Heihei I5!2 September 4th

Claims (3)

[Claims] (1) Between an active matrix substrate in which an active element is provided for each pixel electrode and a counter electrode substrate in which a counter electrode is provided,
Nematic liquid crystals with positive dielectric anisotropy are dispersed and held in a resin matrix, and a liquid crystal resin composite is sandwiched in such a way that the refractive index of the resin matrix almost matches the ordinary refractive index (n_0) of the liquid crystal used. In the active matrix liquid crystal display element, the refractive index anisotropy Δn of the nematic liquid crystal used is 0.18 or more, the average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, the gap d between both electrodes ( μm), the maximum effective applied voltage V (V) applied to the liquid crystal resin composite is 0.3<R・Δn<0.7(1) 4R<d<8R(2) 0.5R・V<d An active matrix liquid crystal display element characterized by satisfying the relationship: <R.V(3). (2) The resin used in the liquid crystal resin composite of claim 1 is
An active matrix liquid crystal display element characterized by using a liquid crystal resin composite which is a photocurable vinyl resin and is obtained by irradiating a solution in which liquid crystal and the resin are uniformly dissolved and curing the resin. . (3) A projection type active matrix liquid crystal display device, characterized in that the active matrix liquid crystal display element according to claim 1 or 2 is combined with a projection light source and a projection optical system.