JPH07230101A - Liquid crystal display element and projection display device using the same - Google Patents

Abstract

PURPOSE:To obtain a reflection type liquid crystal light valve with high contrast and high luminance. CONSTITUTION:This element is a reflection type liquid crystal display element in which nematic liquid crystal is held by scattering in a caking matrix and equipped with a liquid crystal caking complex, and a third electrode 6 is provided on an insulating dielectric film on a wiring part 3 and an active element part 2. The potential of the electrode is kept at low potential so as to always hold the liquid caking complex 7 between picture elements in a scattered state, and also, reflected light from the wiring part 3 can be suppressed, and a satisfactory image can be obtained. In this way, it is possible to obtain a high numerical aperture and a liquid crystal projector with high performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal display device having a liquid crystal electro-optical medium that operates in a transmission / scattering mode.

[0002]

2. Description of the Related Art Projection type display elements using liquid crystal display elements as light valves have been actively developed as a strong candidate for small and lightweight large screen display, and have already been sold as products from NTSC level to HDTV level. Has reached the end. All of the products that have been commercialized so far use a liquid crystal light valve of twisted nematic (TN) system, and the display mode thereof is also transmissive.

If the normally white mode is adopted, a contrast ratio of 100 or more can be easily obtained, and a clear projected image can be realized. On the other hand, as a method that does not use a polarizing plate, a liquid crystal solidified substance composite display element utilizing a transmission-scattering mode has been actively developed.

[0004]

The conventional TN type transmission type light valve has the following drawbacks.

First, in the TN system, a polarizing plate must be used in principle, and at least 50% of the light incident there is lost. As a result, the white brightness of the projected image becomes low, and a clear image can be obtained in a room where the surroundings are kept dark, but in a general environment where there is illumination or outside light enters. Below, the contrast was remarkably reduced, and it was difficult to obtain a bright and clear display image.

In the light valve, the area ratio of the wiring and the active element portion in the pixel increases as the definition of the display becomes higher, and the aperture ratio of the display tends to decrease. Therefore, the projection type display device using the transmissive light valve has a problem that the white luminance of the projected image is reduced as the resolution is increased.

In order to solve this point, a projection type display device using a reflection type display element has been proposed (see the Autumn National Convention of the Institute of Electronics, Information and Communication Engineers 1989, C-30 and C-31). However, it is quite difficult to obtain high brightness because the TN liquid crystal light valve is used. Further, the manufacturing process itself for forming an aluminum electrode having a high reflectance through a liquid crystal cell process accompanied by heat treatment is generally difficult, and sufficient brightness cannot be obtained.

Further, the projection optical system in which the dichroic mirror and the transmissive liquid crystal display light valve are combined has a drawback that the volume of the entire system becomes large.

[0009]

The present invention has been made in view of the above problems. First, as a first invention, in a liquid crystal display device having a liquid crystal electro-optical medium, for example, pixel gaps other than pixels are provided. As described above, there is provided a means for keeping the crystal electro-optic medium in an operation-free area that does not need to be turned on / off in an electrically stable state. Specifically, a plurality of row wirings and a plurality of column wirings are provided on a substrate, an active element is provided near an intersection of the row wirings and the column wirings, a gate electrode of the active element is connected to the row wiring, and a source is provided. The electrodes are connected to the column wirings, the drain electrodes are connected to the display electrodes, and the active matrix substrate is formed by forming the insulating layer so as to cover at least the row wirings, the column wirings, and the active elements, and the transparent electrodes are formed on the substrate. A liquid crystal solidified composite in which a nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a solidified matrix is sandwiched between the counter electrode substrate and the counter electrode substrate, and row wiring, column wiring, and A third electrode is formed so as to cover part or all of the active element, and the potential of the third electrode is kept below the threshold value of the liquid crystal solidified composite layer with respect to the potential of the counter electrode. To provide the first liquid crystal display element .

In a second aspect of the invention, in a liquid crystal display device provided with a liquid crystal electro-optical medium, the pixel electrode has a double structure in the thickness direction of the device, and a reflection function layer is provided between the pixel electrode and the upper electrode. A liquid crystal display device having a structure in which a liquid crystal electro-optical medium is driven and light is reflected by a reflective function layer. Specifically, a counter electrode substrate on which transparent electrodes are formed, row wirings, column wirings, and active elements are provided near the intersections of row wirings and column wirings on the substrate. An active matrix liquid crystal display element comprising a liquid crystal electro-optic medium whose scattering state changes according to an electric field applied state, and an active matrix liquid crystal display element having a reflection function layer formed so as to cover the pixel display electrode. Provides a second liquid crystal display element, which is a transparent electrode formed on or above the reflective functional layer. Further, there is provided a projection type liquid crystal display device comprising any one of the above liquid crystal display elements, a light source system, a color separation / combination optical system, and a projection optical system in combination.

The present invention and its operating principle will be outlined below. First, the first invention will be described.

In the liquid crystal display element of the first invention, an insulating dielectric film is formed on the active elements, the row wirings, the column wirings, and the pixel electrodes on the active matrix substrate, and the insulating film between the pixels is formed thereon. A third electrode is provided so as to cover part or all.

FIG. 1 shows a partial sectional view of the basic structure of this liquid crystal display element, and FIG. 2 shows a plan view thereof.

In these figures, the substrate 1 is a substrate such as glass, quartz, or a silicon wafer. Reference numeral 2 is an active element such as a thin film transistor (TFT), a diode or a MOS transistor. 3 is a column electrode or column wiring, 4 is ITO
Alternatively, a pixel electrode formed of metal is shown. Reference numeral 5 is a reflection function layer that covers these, and specifically, a dielectric multilayer thin film mirror is used. Reference numeral 6 is an inter-pixel electrode formed as a third electrode for a display electrode formed on the front substrate or the back substrate, and 7 is a liquid crystal solidified composite. Further, 8 is a counter electrode made of ITO or the like,
Reference numeral 9 indicates a transparent counter substrate.

As shown in FIG. 2, the third electrode 6 is
Areas other than the pixel electrode 4 are provided in a thick grid pattern.
Most of the row wirings (row electrodes), the column wirings (column electrodes), and the active elements are covered with the inter-pixel electrodes 6 and arranged below them.

Next, the optical function will be described. As shown in FIG. 1, the incident light 10 is emitted from the substrate 9 side at a predetermined angle with respect to the substrate vertical direction. Since the pixel is transparent when voltage is applied to the pixel part,
The incident light is reflected as it is by the reflection function layer 5 composed of a dielectric multilayer thin film mirror or the like, and becomes a white display state when visually recognized from the outside.

When no voltage is applied, the pixel is in a light scattering state, the incident light is not reflected in a predetermined direction, and black display is performed.

The liquid crystal electro-optical medium is not limited to the liquid crystal solidified substance composite in which the liquid crystal is dispersed and held in the solidified substance matrix such as a polymer, and the liquid crystal is operated by the electric field to change the scattering-transmission state. Any material can be used, and examples thereof include a cholesteric liquid crystal and a smectic liquid crystal in addition to the liquid crystal solidified substance complex. Among them, a liquid crystal solidified composite having excellent responsiveness and contrast is suitable as the liquid crystal electro-optical medium used in the present invention.

An example of a liquid crystal solidified substance composite in which a nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a solidified substance matrix and is in a scattered state in the absence of an electric field or in which the scattered state is weakened by the application of an electric field to be in a transmissive state is shown below. Explained.

Usually, in a TN liquid crystal device, a black mask is formed on the counter electrode substrate with an opaque metal or the like to eliminate unnecessary light and prevent the contrast of the displayed image from being lowered. However, in the case of the transmission / scattering type optical element as in the present invention, the metal film on the counter substrate causes reflection at the interface between the counter substrate and the metal, resulting in a reduction in contrast.

On the other hand, as shown in FIG.
That is, on the dielectric multilayer thin film mirror or so as to cover all or part of the column electrodes and / or the row electrodes, or
An inter-pixel electrode should be formed as a third electrode on the upper side of the underlying layer, and it should be kept below the threshold value of the liquid crystal solidified composite with respect to the potential of the transparent electrode on the counter substrate. For example, since the liquid crystal solidified composite on the inter-pixel electrode shown by the region 20 in FIG. 1 is kept in the light scattering state, this part stably displays black.

On the other hand, when the inter-pixel electrode is not provided, the liquid crystal solidified composite in the region other than the pixel display electrode becomes transparent under the influence of the potential of the column electrode or the row electrode which originally does not directly affect the display, The light reflected from the area significantly deteriorates the contrast of the image.

According to the first aspect of the present invention, a dielectric thin film multilayer mirror and a pixel as a third electrode for preventing contrast reduction on the mirror are provided on an active matrix type substrate designed for a normal transmission type optical element. A reflection type panel can be obtained only by forming additional inter-electrodes, and there is no need to specially design the pixel electrode structure and process also serving as the reflection mirror.

The inter-pixel electrode can be easily driven by inputting the same signal as the signal applied to the counter electrode, and the liquid crystal-solidified composite on the inter-pixel electrode (region 2).
0) can always be in the off state (the strongest scattering state). A metal electrode, a transparent electrode, or the like can be used as the inter-pixel electrode, but in the structure of the present invention, it also serves as a light-shielding film of the active element, and therefore it is preferable to use a metal film.

As a result, the active element is protected from the incident light by both the metal film and the dielectric multilayer film mirror, and the occurrence of problems such as light leakage can be suppressed even when an extremely strong light is incident. From the viewpoint of improving contrast, it is preferable that the inter-pixel electrodes cover all of the pixels,
It suffices to cover at least a part of the wiring and the active element.

Up to this point, the case has been described where a dielectric multilayer mirror is used as the reflection function layer and a third electrode for preventing contrast reduction is provided thereon, but the pixel electrode itself can also be used as the reflection mirror electrode. Is. A metal electrode can be used as the mirror / pixel electrode. In this case, the insulating film on the pixel electrode may have a high transparency. Even in this case, as an insulating film,
It is also possible to use a dielectric multilayer film mirror.

FIG. 3 further illustrates a structure suitable for a reflective display device. FIG. 3 is a partial cross-sectional view of an active matrix substrate used in the liquid crystal display element of the first invention.

In the figure, 11 is a substrate such as glass, quartz or silicon wafer, 12 is an active element such as TFT, diode, MOS transistor, 13 is a column electrode or column wiring, 1
Reference numeral 4 denotes a pixel electrode formed of ITO or metal. 1
Reference numeral 5 is a first insulating film formed on the active element, 16 is a second insulating film formed on the pixel electrode, and 17 is an inter-pixel electrode used as a third electrode. An insulating dielectric film is specifically used as the insulating film. In this example, the insulating film has a double structure.

As in the case of the example of FIG. 1, a voltage is applied to the inter-pixel electrode so that the potential of the counter electrode is less than or equal to the threshold potential of the liquid crystal solidified composite. In this way, the liquid crystal solidified composite on the inter-pixel electrode is in a light scattering state, and the incident light is not reflected in a predetermined direction, resulting in black display.

In the case of FIG. 3, compared with the case of the example of FIG. 1, the structure of the active matrix substrate is slightly complicated, but since the wiring and a part of the active element can be covered with the pixel electrode, the aperture ratio is increased. Can be further increased. In this case, it is preferable that one of the first insulating film 15 and the second insulating film 16 be a reflection function layer such as a dielectric multilayer film mirror.

When the first insulating film 15 on the active element is a dielectric multilayer film mirror, the pixel electrode 14 is a transparent electrode such as ITO, and the second insulating film 16 is the pixel electrode and the third electrode ( The film is made of a film (for example, silicon oxide) that has high transparency while maintaining insulation with the inter-pixel electrode). On the other hand, when the second insulating film 16 is a dielectric multilayer film mirror, the pixel electrode 14 does not need to be transparent, and a metal electrode other than ITO can be used.

When a scattering type element such as a liquid crystal solidified substance composite is used as a light valve, it is highly integrated with a projection optical system, unlike a transmission-absorption type element such as a TN type which utilizes absorption by a polarizing plate. Contrast etc. are achieved. In this projection optical system, the transmitted light in the transmitted state is projected and the diffused light in the scattered state is not projected,
Devices that reduce diffused light, such as Schlieren optics, for example
The display contrast can be increased by installing a kind of aperture such as an aperture or a spot.

The F number (F) of the projection optical system using such a scattering type display device is defined by the focal length f of the projection lens system and the diameter d of the diaphragm, and F = f / 2d, Diffused light scattered at an angle θ = arctan (d / f) or more is removed by this projection optical system.

In the projection display device of the present invention, generally, 4 ≦ F ≦ 12, especially 5 ≦ F ≦ 10.

As the F-number increases, the diaphragm is closed and the contrast increases, but the amount of light transmission in the transmission state decreases. Although the F number is determined by this balance, it is possible to achieve this balance within the above range.

As described above, since the liquid crystal solidified composite is an angle modulation type element that changes the traveling direction (angle) of light by voltage, the traveling direction of light is very different from the absorption type element such as TN type. It has a big meaning.

In this sense, when a metallic reflection mirror such as aluminum is used as the reflection mirror of the scattering type liquid crystal optical element as in the prior art, unless the surface condition is almost perfect mirror surface, the contrast etc. The characteristics are greatly deteriorated.

If the surface of the reflecting mirror has irregularities of about the wavelength order or more, diffused light is generated by the mirror surface even in the transmissive state of the liquid crystal, and the light that should originally be transmitted is removed by the diffused light removing optical system. Since the scattering properties in the scattering state are governed by the scattering properties of the liquid crystal, the unevenness present on the mirror surface lowers not only the light utilization efficiency but also the contrast.

In a light-absorption optical element such as a TN liquid crystal optical element, the contrast is determined by the absorption by the polarizing plate. Therefore, the presence of such diffused light does not cause a large decrease in the contrast, and conventionally, the metal mirror such as aluminum is used. Has been used. On the other hand, in the case of the scattering type liquid crystal optical element, the shape of the mirror surface is a very important factor, so that the pixel electrode easily reacts with a silicon-based insulating film like aluminum to form unevenness. The materials are not suitable, and refractory metals are preferred.

In the liquid crystal solidified substance complex, a scatterer called liquid crystal is positionally fixed by a solidified substance matrix such as a polymer. This effectively works to prevent deterioration of spatial information due to distortion of an electric field between pixels. In other scattering-type liquid crystal elements, scattering occurs at the boundary between the micro domains formed by the liquid crystal, but this is not fixed positionally and is determined by the state of the electric field at that time. .

That is, the spatial resolution changes depending on the state. In the case of a liquid crystal-solidified composite, the spatial resolution is determined by the size of the immobilized liquid crystal (particles or a spatial structure equivalent to it), so the spatial resolution depends on the image information at that time. There is almost nothing.

Usually, the size of the liquid crystal dispersed and held in the matrix is about 0.5 to 5 μm, more preferably about 1.5 to 4 μm. This means that in the pixel size of an ordinary active matrix liquid crystal element (usually about 10 to 200 μm), it is possible to sufficiently display each pixel information with almost no deterioration.

From this, it can be said that the use of the liquid crystal solidified composite in the electrode constitution of the present invention is most suitable for high definition, high contrast and high brightness display. As described above, in the structure of the present invention using the liquid crystal solidified composite, it is possible to simultaneously achieve high definition, high brightness and high contrast without impairing other properties.

Next, the second invention will be described. Figure 1
FIG. 0 shows a partial cross-sectional view of the liquid crystal display element. Reference numeral 1 is a substrate such as glass, quartz, or silicon wafer, 2 is an active element such as TFT, diode, MOS transistor, 3 is a column electrode or column wiring, and 4 is a pixel electrode formed of ITO or metal. Reference numeral 5 is a reflection function layer using a dielectric multilayer thin film mirror, 15 is a contact hole or a through hole for connecting an electrode for driving an active element and the pixel electrode 4 on the reflection function layer 5, and 7 is a liquid crystal solidified compound composite. It is a scattering type liquid crystal electro-optic medium such as a body. Further, 8 is a counter electrode made of ITO or the like, and 9 is a transparent counter substrate.

As shown in FIG. 10, the incident light 10 is emitted from the counter electrode 8 side at a predetermined angle with respect to the substrate vertical direction. When the liquid crystal electro-optical medium is in a transparent state, the incident light is reflected as it is by the reflection function layer 5 to provide white display. When the liquid crystal electro-optical medium is in the scattering state, the pixel is in the light scattering state, and the incident light is not reflected in a predetermined direction, and black display is performed.

The liquid crystal electro-optical medium may be any one as long as the liquid crystal operates by an electric field to change the scattering-transmission state, and a liquid crystal solidified substance composite in which the liquid crystal is dispersed and held in a solidified substance matrix such as a polymer, a cholesteric liquid crystal. , Smectic liquid crystals, and the like. Among them, the liquid crystal solidified substance composite having excellent responsiveness and contrast is suitable as the liquid crystal electro-optical medium used in the second invention.

An example of a liquid crystal solidified substance composite in which nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a solidified substance matrix and is in a scattered state in the absence of an electric field, and is weakened in a scattered state by application of an electric field, is shown below. Explained.

Usually, in a TN liquid crystal element, a black mask is formed of an opaque metal or the like on the counter electrode substrate to eliminate unnecessary light and prevent a reduction in contrast of a display image. However, in the case of the scattering type display element as in the present invention, the metal film on the counter substrate causes reflection at the interface between the counter substrate and the metal, resulting in a reduction in contrast. On the other hand, if the black mask on the counter substrate is simply removed, the liquid crystal solidified composite becomes transparent due to the voltage between the row wiring, the column wiring, and the counter electrode, and the incident light is reflected on the surface of the row wiring and the column wiring. Since the light reaches and is reflected, unnecessary reflected light is increased and the contrast of the image is deteriorated.

In order to prevent this, pixel electrodes using a metal film of aluminum or the like are formed on the interlayer insulating film by row wiring, column wiring,
Although it has been attempted to form the active element so as to cover it as much as possible, it is generally difficult to obtain an aluminum surface having a good reflectance.

Therefore, in the present invention, in order to achieve a high aperture ratio and a high light utilization efficiency without lowering the contrast, the dielectric multilayer thin film mirror is used as described above, and the display electrode is formed of a transparent electrode such as ITO. With this configuration, the reflectance is not deteriorated and stable characteristics can be obtained at about the heat treatment temperature in the liquid crystal cell assembling process.

Further, the dielectric multilayer thin film mirror usually has a larger film thickness than various films constituting the thin film active element, and when connecting the electrode of the active element and the display electrode on the mirror, the through hole opened in the mirror is used. Hole coverage is a problem, but I
A transparent electrode such as TO is excellent in covering property and is advantageous.

On the other hand, since the thickness of the mirror is large, the overlapping capacitance is small even when the display electrodes are overlapped with the row wirings or the column wirings. If they are not overlapped, the liquid crystal solidified composite is interposed between the display electrodes and the counter electrode. Since the capacitance is approximately the same as that of the capacitor formed, it is possible to avoid a large drive problem such as a rounded waveform.

The structure according to the second aspect of the invention is particularly effective in the scattering type liquid crystal display element and can exhibit excellent characteristics. When a scattering type element such as a liquid crystal solidified compound composite is used as a light valve, it is very different from a transmission-absorption type element such as a TN type which utilizes absorption by a polarizing plate, and it is possible to obtain a high contrast when integrated with a projection optical system. To be achieved.

In this projection optical system, a device for reducing diffused light such as a schlieren optical system, for example, a kind of aperture such as an aperture or a spot, so that transmitted light in a transmitted state is projected and diffused light in a scattered state is not projected. By installing, the display contrast can be increased.

The F-number of the projection optical system using such a scattering type display element has already been described in the first invention.

In the second invention of the present application, since the dielectric multi-layer film mirror is used as the reflecting mirror, a good mirror surface is provided even after the thermal process, and the scattering type element has high contrast and high light. Achieve utilization efficiency. A high reflectance can be achieved only by forming a dielectric multilayer mirror on a pixel electrode of a conventional transmissive display element, but it cannot be said to be excellent in terms of aperture ratio and driving voltage.

In such a structure, the aperture ratio is only equal to that of the transmissive display element, and the aperture ratio is extremely lowered as the resolution becomes higher. Further, since both the liquid crystal medium and the reflection mirror are sandwiched between the pixel electrode and the counter electrode, a part of the voltage is lost by the reflection mirror layer, resulting in an increase in drive voltage.

In the second invention, since the transparent electrode is arranged as the pixel electrode on the dielectric multilayer film mirror,
There are few factors that limit the aperture ratio, and a large aperture ratio can be achieved. Further, since there is no mirror between the pixel electrode and the counter electrode, the applied voltage is used only for driving the liquid crystal optical medium, and the driving voltage hardly rises.

Therefore, forming the pixel electrode with the transparent electrode on the dielectric multilayer thin film mirror is an excellent means for preventing the deterioration of the electrical characteristics while improving the aperture ratio and the contrast.

As the scattering type element to be used, an element which is in a scattering state when no voltage is applied is most suitable. In this case, since the portion of the gap between the pixel electrodes is always in a scattering state, that portion is projected as black even if no special light shielding means such as a black mask is provided on the counter substrate side. For this reason,
There is no decrease in aperture ratio due to the black mask, and in principle 1
It is possible to achieve an aperture ratio close to 00%.

In the case of the TN type element, since light leakage occurs at the end portion of the pixel electrode due to the distortion of the electric field, a black mask is indispensable even if the electrode structure of the present invention is adopted, and the aperture ratio is Be hindered. Therefore, in the device of the present invention, the utilization efficiency can be increased more than the improvement of the light utilization efficiency by not using the polarizing plate. In this case, it is desirable that the pixel electrode be configured to cover the row wiring (row electrode) and the column wiring (column electrode) as much as possible. In the row wirings and column wirings in the gaps between the pixel electrodes, the voltage between the wirings and the counter electrodes causes the liquid crystal solidified substance complex to be in a transparent state, increasing unnecessary reflected light and degrading image contrast. Is.

Regarding the overlap between the pixel electrode and the wiring portion, it is desirable to arrange the pixel electrode so that the area of 80% or more of the wiring portion is hidden, and more desirably 90%.
That is all. By doing so, a special light shielding means between pixels can be unnecessary. Of course, in this case
It is also possible to provide a black mask on the counter substrate so as to cover minute wiring portions remaining between pixels. Even in this case, it is not necessary to cover the entire inter-pixel region with a black mask as in a normal TN type element. As described above, with the structure of the present invention, it is possible to achieve a very high aperture ratio, which has been extremely difficult in the past.

Next, the liquid crystal solidified composite used as the electro-optical medium will be described.

As the liquid crystal solidified substance complex used in the present invention, a liquid crystal solidified substance complex composed of a solidified substance having a large number of fine pores formed therein and a nematic liquid crystal filled in the pores is used. When no voltage is applied between the electrodes,
The refractive index of the solidified substance and the refractive index of the liquid crystal become inconsistent,
Scattered. On the contrary, when a voltage sufficiently higher than the threshold voltage is applied, the refractive index of the solidified substance and the refractive index of the liquid crystal become the same, and the liquid crystal becomes in the transmissive state. The term "refractive index of the solidified product" as used herein means the refractive index of the solidified product when it is swollen by the liquid crystal.

A liquid crystal solidified substance composite consisting of a solidified product having a large number of fine pores formed therein and a liquid crystal filled in the pores has a structure such that the liquid crystal is enclosed in a liquid bubble such as a microcapsule. However, individual microcapsules do not have to be completely independent, and liquid bubbles of individual liquid crystals may communicate with each other through a slit like a porous body.

The liquid crystal optical element of the present invention has a structure in which a nematic liquid crystal is dispersed and held in a solidified material. This liquid crystal optical element may be manufactured by impregnating a nematic liquid crystal into a solidified product having holes, but in view of productivity, uniformity, scattering properties, etc., a mixture of a nematic liquid crystal and a curable compound is used as a raw material. It is preferable that the compound is produced by a production method in which the nematic liquid crystal is separated when the curable compound is cured.

Specifically, a uniform solution of a nematic liquid crystal and a curable compound is used, and when the curable compound is cured,
A method of producing a liquid crystal solidified substance complex in which a nematic liquid crystal is dispersed in a solidified substance matrix by causing phase separation is preferable. According to this manufacturing method, a uniform liquid crystal solidified product composite can be manufactured with high productivity. Here, the hardening to form a solidified product includes hardening such that a monomer or oligomer is polymerized, hardening by crosslinking, and solidification by cooling from a molten state by heat.

Further, an emulsion is formed from the nematic liquid crystal and the curable compound, and the nematic liquid crystal and the curable compound are previously separated into a fine dispersion state, and the curable compound is cured to fix the dispersion. A manufacturing method is also possible.

Particularly preferred in the present invention is a method of producing a nematic liquid crystal and a curable compound by phase separation from a uniform solution. Therefore, it is preferable to use a photocurable compound as the curable compound from the viewpoint of productivity. That is, since it is not necessary to remove the solvent, it can be cured in a closed system, and the conventional T
Since the method of injecting into the cell like the N-type liquid crystal display element can be used, the productivity is good. Further, since it can be cured by irradiation with light, the curing step is short and the control of the liquid crystal particle size is easy, which is preferable.

In this case, it is preferable to use a photocurable vinyl compound. Specifically, a photocurable acrylic compound is exemplified, and a compound containing an acrylic oligomer that is polymerized and cured by light irradiation is particularly preferable.

Further, in the present invention, since there is no black mask on the counter substrate side, uniform photopolymerization and curing by ultraviolet rays can be easily performed.

The nematic liquid crystal used in the present invention is a liquid crystal in which the refractive index of the solidified product matches the refractive index of the liquid crystal when a voltage is applied or not applied, and is used alone. Although the composition may be used, it can be said that the composition is more advantageous for satisfying various performance requirements such as operating temperature range and operating voltage. In particular, it has a positive dielectric anisotropy, the refractive index of the solidified is, use of liquid crystal, such as to match the ordinary refractive index n _O of the liquid crystal is preferred.

When a photocurable compound is used in the liquid crystal used in the liquid crystal solidified substance composite, it is preferable that the photocurable compound is uniformly dissolved, and the cured product after photoexposure is not dissolved. Alternatively, when the composition is used, it is desirable that the solubility of each liquid crystal be as close as possible.

In the case of producing a liquid crystal solidified composite, like a conventional ordinary liquid crystal optical element, a substrate with a pair of electrodes is arranged so that the electrode surfaces face each other, and the periphery is sealed with a sealing material. The liquid mixture for uncured liquid crystal solidified composite may be injected from the injection port to seal the injection port, or the uncured mixture of the curable compound and the liquid crystal is supplied on one substrate. Alternatively, the other substrate may be manufactured by stacking the other substrates so that the electrode surfaces face each other.

A dichroic dye, a simple dye or a pigment may be added to the liquid crystal of the liquid crystal solidified composite used in the present invention, or a colored curable compound may be used. In addition, a viscosity modifier, a spacer for adjusting the gap between the electrodes, a non-liquid crystal additive, and the like may be added.

In the present invention, liquid crystal is used as a solvent in the liquid crystal solidified substance complex, and the photocurable compound is cured by photoexposure, so that there is no need to evaporate a simple solvent or water which is unnecessary at the time of curing. Therefore, since it can be cured in a closed system, the conventional manufacturing method of injecting into a cell can be adopted as it is, it is highly reliable, and it also has the effect of adhering two substrates with a photocurable compound. Will be more likely.

By thus forming the liquid crystal solidified composite, the risk of short circuit between the upper and lower transparent electrodes is low, and
Unlike the normal TN type display element, it is not necessary to strictly control the orientation and the substrate gap, and a liquid crystal optical element capable of controlling the transmission state and the scattering state can be manufactured with extremely high productivity.

The optimum configuration of the liquid crystal solidified composite element used in the present invention may be optimized by the following factors depending on the application. The factors that determine the electro-optical characteristics of the liquid crystal optical element using the liquid crystal solidified substance complex are the refractive index of the liquid crystal used (ordinary light refractive index n _O , extraordinary light refractive index n _e ), viscosity η, and the solidified product refractive index. n _M , the average particle diameter R of the liquid crystal dispersed and held in the solidified matrix, and the gap between the substrates with electrodes (thickness of the liquid crystal solidified composite) d.

In addition to the above, the relative permittivity of the liquid crystal, the elastic constant, the relative permittivity ε _M of the solidified material used, the elastic modulus, and the volume distribution rate Φ of the liquid crystal dispersed and held in the solidified matrix, It is preferable to optimize the maximum effective applied voltage V and the like for driving.

The liquid crystal average particle diameter R of the present invention means that when the liquid crystal is independent particles or particles in which some of them are connected,
It means the maximum diameter of the particles, and in the case of a structure in which most of the liquid crystals are in communication, it means the maximum diameter of the region where the directions of the directors of the liquid crystals correlate with each other.

The liquid crystal dispersed and held in the solidified matrix is preferably independent particles or particles in which some of them are in communication. This is effective in that it can be driven at a low voltage and has both high scattering ability and high transparency.

The electro-optical properties of the liquid crystal optical element using the liquid crystal solidified composite of the present invention have a high scattering property when a voltage is applied or not applied, and a high transmission property when the other is applied. It is desired to have a high contrast ratio. When a projection type display device is configured using such a liquid crystal optical element, a projection device having a high transmittance (effective use of the light amount of a light source) and a high contrast ratio can be obtained.

The most important object of the present invention is to obtain a liquid crystal optical element using a liquid crystal solidified composite which exhibits a high contrast ratio (on / off ratio). In the following description, a liquid crystal optical element in which the refractive index n _M of the solidified substance is made to match the ordinary refractive index n _O of the liquid crystal used and which is in a transmissive state when a voltage is applied will be described as an example.

The refractive index anisotropy Δn of the liquid crystal used contributes to the scattering property when no voltage is applied, and in order to obtain high scattering property,
It is preferable that it is larger than a certain level, specifically, Δn ≧
0.18, and Δn ≧ 0.20 is a particularly preferable condition. On the other hand, if Δn is too large, it is disadvantageous in terms of transparency, threshold value characteristics, and temperature characteristics at the time of turning on. Therefore, Δn ≦ 0.29 is preferable.

Further, it is preferable that the ordinary refractive index n _O of the liquid crystal used is substantially the same as the refractive index n _M of the solidified product, and at this time, high transparency is obtained when a voltage is applied. Specifically, n _O
It is preferable that the relationship of −0.03 <n _M <n _O +0.05 is satisfied.

The average particle diameter R of the liquid crystal dispersed and held in the solidified matrix is a very important factor and contributes to the scattering property when no voltage is applied and the operating characteristics of the liquid crystal when a voltage is applied. The scattering property at the time of no voltage changes depending on the relationship among the refractive index anisotropy Δn of the liquid crystal used, the wavelength λ of light, and the average particle diameter R of the liquid crystal. The maximum scattering property is that the average particle diameter R (μm) is

It is when the relation of 0.3 <Δn · R <0.8 (1) is satisfied.

When the average particle diameter R is smaller than the range of the formula (1), the response speed becomes faster, but the scattering ability per unit operation liquid crystal amount becomes lower and the voltage required for driving becomes higher. On the other hand, when the average particle diameter R is larger than the range of the formula (1), it can be driven at a low voltage, but the scattering ability per unit operation liquid crystal amount is lowered and the response speed becomes slow.

The particle size of the liquid crystal is preferably uniform. When the particle diameters are distributed, large liquid crystal particles lead to a decrease in scattering ability, and small liquid crystal particles lead to an increase in drive voltage, resulting in an increase in drive voltage and a decrease in contrast. The dispersion σ of the particle diameter is preferably within 0.25 times the average particle diameter, more preferably within 0.15 times. The average particle diameter and the dispersion are the weighted average and dispersion.

The thickness of the liquid crystal solidified composite, that is, the gap d (μm) between the electrodes is also an important factor. When d is increased, the scattering property in the absence of voltage is improved and the threshold characteristics are sharpened. However, if d is too large, a high voltage is required to achieve sufficient transparency when a voltage is applied, which leads to an increase in power consumption and a driving I of a conventional TN liquid crystal display device.
There arise problems that C cannot be used and that the threshold characteristics deteriorate. Further, if d is made small, high transparency can be obtained at a low voltage, but the scattering property at the time of no voltage decreases. For this reason,

It is preferable that the relationship of 3R <d <8R (2) is satisfied. By satisfying the relation of the expression (2), it is possible to obtain a high scattering property at the time of off, a high transparency at the time of on, and a good threshold characteristic.

In the projection type display device using the display element of the present invention, a high contrast can be exhibited by using a device for reducing diffused light in the projection optical system. A device that reduces diffused light is a light that does not go straight (liquid crystal resin composite) out of the light that has passed through the liquid crystal display element The light that is scattered in the scattered state) may be reduced. In particular, it is preferable that the light that goes straight does not decrease, and the light that does not go straight decreases the diffused light.

As another example, instead of an aperture or a spot, a mirror having a small area may be obliquely arranged at the same position, reflected and projected through a projection lens arranged on its optical axis. it can. Further, a spot, a mirror or the like may be installed at a position where the light beam is focused by the projection lens without using such a condenser lens. Further, the focal length and aperture of the projection lens may be selected so as to remove scattered light without using a special aperture or the like.

A microlens system or the like can also be used. Specifically, by disposing a microlens array and a spot array in which fine holes are arrayed on the projection optical system side of the liquid crystal display element, unnecessary scattered light can be removed. In this case, since the optical path length required for removing scattered light can be made extremely short, there is an advantage that the entire projection display device can be made compact. In order to shorten the optical path length, it is also effective to incorporate a scattering elimination system in the projection optical system. In this case, the size of the optical system can be reduced and the size of the optical system can be simplified as compared with the case where the projection optical system and the scattering elimination system are independently installed.

These optical systems can be combined with a mirror, a dichroic mirror, a prism, a dichroic prism, a lens, etc. to synthesize images and colorize them. Also,
Images can be colored by combining with a color filter. The ratio of the straight component and the scattered component reaching the projection screen can be controlled by the diameter of the spot, the mirror or the like and the focal length of the lens, and may be set so that desired display contrast and display brightness can be obtained.

When a device for reducing diffused light is used, it is preferable that the light incident on the liquid crystal display element from the projection light source is more parallel in order to increase the display brightness. For that purpose, a light source with high brightness and as close to a point light source as possible,
It is preferable to configure a projection light source by combining a concave mirror, a condenser lens, and the like.

[0097]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the first invention of the present application will be described below with reference to the drawings.

(Embodiment 1) FIG. 4 is a cross-sectional view of the vicinity of one pixel of a liquid crystal display element when the basic structure shown in FIG. 1 is applied to a TFT array. And FIG. 5 is a plan view.

The TFT array of this embodiment has a semiconductor layer 103, a gate insulating film 104, and a gate electrode 10 formed on a base film 102 formed on an insulating substrate 101.
5, storage capacitor 105A (see FIG. 5), interlayer insulating film 10
6, source / drain electrodes 107 and 108, a dielectric multilayer mirror 109 formed so as to cover them, and a black matrix 110 formed on the dielectric multilayer mirror.

Further, in the liquid crystal display element of the present embodiment, the liquid crystal solidified composite 130 is sandwiched between the transparent counter substrate 121 on which the transparent electrode 122 is formed and the substrate 101 on which the TFT array is formed.

The manufacturing process of the TFT array will be described below. Base film 1 on glass substrate 101 by plasma CVD method
Silicon oxide to be 02, amorphous silicon, and silicon nitride are sequentially stacked. After hydrogen in the film is released by heat treatment, the amorphous silicon layer is polycrystallized using a laser.

The entire surface of the silicon nitride layer is removed by etching, and the polycrystalline silicon film 103 is formed by patterning into a predetermined shape by photolithography.
The silicon nitride layer can be omitted. Although glass was used for the substrate, quartz, ceramics, or the like can be used as long as it is insulating.

Amorphous silicon may be formed by a low pressure CVD method or a sputtering method. A laser was used for polycrystallization, but a heat treatment method near 600 ° C. may be used, or a reduced pressure CV
Polycrystalline silicon may be directly deposited by the D method or the like. In that case, the silicon nitride layer is unnecessary.

Further, a silicon oxide film to be the gate insulating film 104 is formed by plasma CVD and Cr is formed by sputtering. Cr is patterned by the photolithography method to form the gate electrode 105 and the auxiliary capacitance electrode 105A. The silicon oxide layer is dry-etched using this Cr as a mask.

Impurities are implanted into the exposed polycrystalline silicon region by an ion implantation method to form source / drain regions. Heavy-doped polycrystalline silicon, A for the gate electrode
Well-known materials such as l and Ta can be used, and the gate insulating film may be formed by a low pressure CVD method, a sputtering method, or a thermal oxidation method. Further, not only silicon oxide but also silicon nitride, tantalum oxide, or a laminated film thereof may be used.

Next, a silicon nitride film is formed as an interlayer insulating layer by a plasma CVD method, a through hole is formed in the impurity region of the polycrystalline silicon 103 by dry etching, and Cr and Al are sequentially formed by a sputtering method. A source / drain electrode 10 formed by patterning Al and Cr by photolithography and laminated in a predetermined shape.
8 and 107 are formed. The Cr electrode 107 is the Al electrode 10
8 extends to form a pixel electrode.

As the interlayer insulating layer, silicon oxide, oxygen-doped silicon nitride or the like can be used, and low pressure CVD
Method, atmospheric pressure CVD method, sputtering method can also be used.
Known materials such as Mo, W, Ti, and ITO can be used for the source / drain electrodes, or a laminated film thereof may be used.

Next, a dielectric multilayer mirror is formed. An optical film thickness n of a silicon oxide film having a refractive index of 1.45 and a tantalum oxide film having a refractive index of 2.1 are alternately formed by vacuum deposition.
Twenty-three layers are laminated with d = λ / 4 (where λ is the wavelength of red, blue, and green) to form a dielectric multilayer mirror 109 having a reflectance of 98% or more in each wavelength band of red, blue, and green. At this time, the total film thickness of each dielectric multilayer mirror is 1.6 to 2.1.
μm. Here, titanium oxide or the like can be used instead of tantalum oxide.

Next, Cr is deposited by a sputtering method and patterned so as to cover the gaps between the pixel electrodes and the TFT elements to form inter-pixel electrodes 110.

Next, the peripheral terminal region is opened by dry etching to form a TFT array substrate.

Further, the manufacturing process of the liquid crystal display element of this embodiment will be described.

An antireflection treatment 123 for incident light is applied to one surface of the glass substrate 121. The other surface is subjected to antireflection treatment, and then ITO is deposited by a sputtering method to form the counter electrode 122, which is used as the counter electrode substrate.

The nematic liquid crystal, the bifunctional urethane acrylate oligomer, the acrylate monomer, and the photoreaction initiator are uniformly dissolved and injected into a panel having a gap of 12 μm between the electrodes, which is composed of the TFT array substrate and the counter electrode, and is exposed to ultraviolet rays. Polymerization and curing were performed by irradiation to prepare a liquid crystal optical element in which the liquid crystal solidified composite was sandwiched between the substrates. As the spacer, plastic beads having a diameter of about 12 μm were used.

The average particle diameter of the liquid crystal in the solidified matrix was about 2.5 μm. Also, the physical properties of the liquid crystal used are
The refractive index anisotropy Δn in visible light at room temperature was 0.21, the dielectric constant anisotropy Δε was 10.9, and the viscosity was about 35 (cSt). This panel is for green.

Similarly, panels for red and blue were prepared. The gap between electrodes is changed with the panel for green, and about 14μ for red.
m and for blue are about 11 μm. At this time, each dielectric multilayer mirror is adapted to each color.
These panels show a strong scattering state in the off state.
The scattering was reduced from about V, and the reflection mirror state (transmission state of liquid crystal) was almost complete at about 8V.

A projection type display device was constructed as shown in FIG. 6 (plan view) and FIG. 7 (side view). As a light source system, 1
50W metal halide lamp 211, elliptical mirror 212,
Using the light source system 201 including the diaphragm 213,
The parallelism of the light flux from the light source was about ± 4.5 degrees.

Two dichroic mirrors 221 and 222 are used for color separation / combination, and white light is separated into three colors of RGB, and a condenser lens 230 and each liquid crystal display element (liquid crystal panel) 231, 232, 233 are provided there. Was placed. The projection lens 242 used had a diaphragm 241 inside, and the diaphragm was adjusted so that the F number was about 6 (convergence half-angle 4, 8 degrees).

The drive system was set so that the maximum drive voltage was 8 V, and each liquid crystal display element was driven by a video signal.
The black matrix 110 of each liquid crystal display element described above.
Is set to be equal to the potential of the counter electrode 112. When a voltage of 8 V was applied to the entire surface of each panel, the amount of light projected from the projection lens was about 420 (lm). The light amount ratio between the voltage on state and the voltage off state was about 100: 1.

When this projection type display device was used to display a moving image by setting the image on the screen so as to have a diagonal of 100 inches, a moving image display with high brightness and high contrast was obtained, and a normal surrounding environment ( Even when a fluorescent lamp is turned on for indoor lighting), the contrast ratio of black and white is about 5
The ratio was 0: 1, which was comparable to the image in the dark room with the fluorescent lamp off.

As described above, in this embodiment, the conventional T
Since it is possible to obtain a projected image having a brightness far exceeding that of the N-system liquid crystal display element, it is extremely useful as a large-screen display device.

(Embodiment 2) FIG. 8 is a cross-sectional view of the vicinity of one pixel of a liquid crystal display element when the basic structure shown in FIG. 3 is applied to a TFT array. And FIG. 9 is a plan view.

In the TFT array of the second embodiment, the semiconductor layer 303, the gate insulating film 304, and the gate electrode 3 formed on the base film 302 formed on the insulating substrate 301.
05, auxiliary capacitance 305A (see FIG. 9), interlayer insulating film 30
6, source / drain electrodes 307 and 308, an insulating film 309 formed so as to cover these, a pixel electrode 310 formed on this insulating film, and a dielectric formed so as to cover this pixel electrode Multilayer film mirror 311 and black matrix 3 formed on the dielectric multilayer film mirror
It consists of 12.

Further, in the liquid crystal display element of this embodiment, the liquid crystal solidified composite 3 is provided between the transparent substrate 321 having the transparent electrode 322 formed thereon and the substrate 301 having the TFT array formed thereon.
30 is sandwiched.

The manufacturing process of the TFT array will be described below. The base film 3 is formed on the glass substrate 301 by the plasma CVD method.
Silicon oxide to be 02, amorphous silicon, and silicon nitride are sequentially stacked. After hydrogen in the film is released by heat treatment, the amorphous silicon layer is polycrystallized using a laser.

The entire surface of the silicon nitride layer is removed by etching, and the polycrystalline silicon film 303 is formed by patterning into a predetermined shape by photolithography.
Further, a silicon oxide film to be the gate insulating film 304 is formed by plasma CVD, and Cr is formed by sputtering. Cr is patterned by a photolithography method to form a gate electrode 305 and an auxiliary capacitance electrode 305A. The silicon oxide layer is dry-etched using this Cr as a mask. Impurities are implanted into the exposed polycrystalline silicon region by an ion implantation method to form source / drain regions.

Next, a silicon nitride film is formed as an interlayer insulating layer by the plasma CVD method, a through hole is formed in the impurity region of the polycrystalline silicon 303 by dry etching, and Cr and Al are sequentially formed by the sputtering method. A source / drain electrode 30 in which Al and Cr are patterned by a photolithography method and laminated in a predetermined shape.
8 and 307 are formed. The Cr electrode 307 is the Al electrode 30.
8 extends beyond 8 to form an auxiliary capacitance electrode.

Next, a silicon nitride film is formed by a plasma CVD method to form an insulating film 309, and through holes are formed in the portions of the source / drain electrodes 307 and 308 where Cr extends. Further, Cr is deposited by a sputtering method and patterned into a predetermined shape to form the pixel electrode 310.

Next, the dielectric multilayer film mirror 311 is formed by the same method as in the first embodiment. Next, a black matrix 312 is formed by forming a film of Cr by sputtering and patterning so as to cover the gaps between the pixel electrodes.

Next, the peripheral terminal region is opened by dry etching to form a TFT array substrate.

Hereinafter, the manufacturing process of the active matrix type liquid crystal display element is the same as that of the first embodiment. When incorporated in a projection optical system similar to that in Example 1, the projection image becomes brighter because the aperture ratio can be made higher than in Example 1 and 45
It was 0 (lm).

Although the top gate type polycrystalline silicon TFT array is used in the first and second embodiments, the present invention is not limited to this, and the TFT structure may be a bottom gate type and the semiconductor material is amorphous. It may be a high quality silicon or a compound semiconductor. Further, the effects of the present invention can be obtained similarly even in the case of a MOS transistor array formed on a crystalline silicon wafer. Further, a two-terminal element such as a PIN diode or MIM diode may be used as the active element.

An embodiment of the second invention of the present application will be described below with reference to the drawings.

(Embodiment 3) FIG. 11 is a cross-sectional view of the vicinity of one pixel of an active matrix type liquid crystal display element when the above-mentioned basic structure is applied to a TFT. 12 is a plan view.

In the TFT array of this embodiment, the semiconductor layer 403, the gate insulating film 404, and the gate electrode 40 formed on the base film 402 formed on the insulating substrate 401.
5, the auxiliary capacitance 405A, the interlayer insulating film 406, the source / drain electrodes 407 and 408, the dielectric multilayer film mirror 409 formed so as to cover these, and the through holes formed on the source / drain electrodes 407. TFT
And a pixel electrode 410 connected to the pixel electrode 410.

Further, in the active matrix type liquid crystal display element of this embodiment, the liquid crystal solidified composite 414 is sandwiched between the transparent substrate 411 on which the transparent electrode 412 is formed and the active element array.

The process of forming the TFT array will be described below. The base film 4 is formed on the glass substrate 401 by the plasma CVD method.
Silicon oxide to be 02, amorphous silicon, and silicon nitride are sequentially stacked. After hydrogen in the film is released by heat treatment, the amorphous silicon layer is polycrystallized using a laser. The entire surface of the silicon nitride layer is removed by etching, and the polycrystalline silicon film 403 is formed by patterning into a predetermined shape by photolithography.
The silicon nitride layer can be omitted.

Although glass is used as the substrate, quartz, ceramics or the like may be used as long as it has an insulating property. Amorphous silicon may be formed by a low pressure CVD method or a sputtering method. A laser was used for polycrystallization, but a heat treatment method at about 600 ° C. may be used, or polycrystalline silicon may be directly deposited by a low pressure CVD method or the like. In that case, the silicon nitride layer is unnecessary.

Further, a silicon oxide film to be the gate insulating film 404 is formed by plasma CVD and Cr is formed by sputtering. Cr is patterned by a photolithography method to form a gate electrode 405 and an auxiliary capacitance electrode 405A. The silicon oxide layer is dry-etched using this Cr as a mask. Impurities are implanted into the exposed polycrystalline silicon region by an ion implantation method to form source / drain regions. Heavy-doped polycrystalline silicon, A for the gate electrode
Well-known materials such as l and Ta can be used, and the gate insulating film may be formed by a low pressure CVD method, a sputtering method, or a thermal oxidation method.

Further, not only silicon oxide but also silicon nitride, tantalum oxide, or a laminated film of these may be used. Next, a silicon nitride film is formed as an interlayer insulating layer by a plasma CVD method, a through hole is formed in the impurity region of the polycrystalline silicon 403 by dry etching, and C
r and Al are sequentially formed by sputtering. Source / drain electrodes 408 and 40, which are formed by patterning Al and Cr by photolithography to form a predetermined shape.
Form 7.

As the interlayer insulating layer, silicon oxide, oxygen-doped silicon nitride, or the like can be used, and low pressure CVD
Method, atmospheric pressure CVD method, sputtering method can also be used.
A known material such as Mo, W, Ti, or ITO is used for the source / drain electrodes, or a laminated film of these may be used. Next, a dielectric multilayer mirror is formed.

A silicon oxide film having a refractive index of 1.45 and a tantalum oxide film having a refractive index of 2.1 are alternately formed by a vacuum vapor deposition method with an optical film thickness of nd = λ / 4 (λ is a wavelength of red, blue, and green) and 23. Layered and has a reflectance of 9 in each wavelength band of red, blue and green.
The dielectric multilayer mirror 409 is formed so as to be 8% or more. At this time, the total film thickness of each dielectric multilayer mirror is 1.6 to 2.1 μm. Here, titanium oxide or the like can be used instead of tantalum oxide.

Next, of the source / drain electrodes 407 made of Cr, the source / drain electrode 4 made of Al is used.
Dielectric multilayer mirror 409 over the portion extending from 08.
A through hole is formed in the film and an ITO film is formed by the sputtering method. This is patterned into a predetermined shape to form a pixel electrode. The pixel electrode covers adjacent row wirings (column electrodes) and column wirings (column electrodes) as much as possible, thereby improving the aperture ratio. Areas on both adjacent column wirings are made equal and parasitic capacitances between the column wirings and the pixel electrodes are made equal, but the present invention is not limited to this.

Next, the peripheral terminal region is opened by dry etching to form a TFT array substrate. Further, a process of manufacturing the active matrix type liquid crystal display device of this embodiment will be described. Antireflection treatment 413 for incident light is performed on one surface of the glass substrate 111. On the other surface, anti-reflection treatment is applied, and then ITO transparent electrode 412 is applied.
Is deposited by a sputtering method to form a counter electrode substrate.

The nematic liquid crystal, the bifunctional urethane acrylate oligomer, the acrylate monomer, and the photoreaction initiator are uniformly dissolved, and the resulting mixture is injected into a panel having an electrode gap of 12 μm, which is composed of the TFT array substrate and the counter electrode, and is exposed to ultraviolet rays. Polymerization and curing were performed by irradiation to prepare a liquid crystal optical element in which the liquid crystal solidified composite was sandwiched between the substrates. As the spacer, plastic beads having a diameter of about 12 μm were used.

The average particle diameter of the liquid crystal in the solidified material matrix was about 2.5 μm. Also, the physical properties of the liquid crystal used are
The refractive index anisotropy Δn in visible light at room temperature was 0.21, the dielectric constant anisotropy Δε was 10.9, and the viscosity was about 35 (cSt). This panel is for green. Similarly, panels for red and blue were created. The gap between the electrodes for the green panel was changed to about 14 μm for the red panel and about 11 μm for the blue panel. At this time, each dielectric multilayer mirror is adapted to each color. These panels showed a strong scattering state in the off state, and the scattering was reduced from about 4V, and it became a nearly complete reflection mirror state (transmission state of liquid crystal) at about 7V.

As in the case of the first embodiment of the invention, FIG.
And a projection display device was constructed as shown in FIG. As a light source system, a 150W metal halide lamp 21
1, the light source system 201 including the elliptic mirror mirror 212 and the diaphragm 213 was used, and the parallelism of the light flux from the light source was about ± 4.5 degrees.

Two dichroic mirrors 221 and 222 are used for color separation / combination, and white light is separated into three colors of RGB, and there is a condenser lens 230 and each panel 231 and 23.
2, 233 were placed. The projection lens 242 used had a diaphragm 241 inside, and the diaphragm was adjusted so that the F number was about 6 (condensing half-angle 4.8 degrees).

The drive system was set so that the maximum drive voltage was 7 V, and each panel was driven by a video signal. When a voltage of 7 V was applied to the entire surface of each panel, the amount of light projected by the projection lens was about 600 (lm). The light amount ratio between the voltage on state and the voltage off state was about 100: 1.

Using this projection type display device, when a moving image was displayed by setting the image on the screen so as to have a diagonal of 100 inches, a moving image display with high brightness and high contrast was obtained, and a normal surrounding environment ( Even when a fluorescent lamp is turned on for indoor lighting), the contrast ratio of black and white is about 5
It was 0: 1, which was comparable to the image in the dark room state where the fluorescent lamp was turned off.

As described above, in the present embodiment, the conventional T
Since it is possible to obtain a projected image having a brightness far exceeding that of the N-system liquid crystal display element, it is extremely useful as a large-screen display device. Although the top gate type polycrystalline silicon TFT array is used in the present embodiment, the present invention is not limited to this, and the structure of the TFT may be a bottom gate type, and the semiconductor material is amorphous silicon or a compound semiconductor. But it's okay. Further, the effects of the present invention are the same even for a MOS transistor array formed on a crystalline silicon wafer. Further, a two-terminal element such as a PIN diode or MIM diode may be used as the active element.

Reference Example 1 A partial sectional view of an application example of the first invention is shown in FIG. The same reference numerals indicate the same components.
In this reference example, the transparent electrode of the counter substrate is formed with fine irregularities, which has an effect of removing unnecessary regular reflection light. It also has the effect of reducing the hysteresis phenomenon. The third electrode has a function as a light-shielding film for the active element, in addition to holding the electro-optical medium in an unnecessary area below the threshold value.

Reference Example 2 A partial sectional view of an application example of the second invention is shown in FIG. The same reference numerals indicate the same components.
7A is an encapsulated liquid crystal, and 7B is a solidified product, and a layer of the liquid crystal solidified composite 7 is formed by both. Also,
In this reference example, the transparent electrode of the counter substrate is formed with fine irregularities, which has an effect of removing unnecessary regular reflection light. It also has the effect of reducing the hysteresis phenomenon. And
The electro-optic medium is driven by the upper pixel electrode of the double electrode structure. The incident light is reflected by the reflection function layer 5 when the electro-optical medium in the transmission / scattering mode is in the transparent state.

In these reference examples, a light absorbing black paint is applied to the back surface of the substrate 1 in order to reduce back surface reflection of residual transmitted light.

[0154]

As described above, according to the present invention, a reflection type liquid crystal light valve having high brightness and high contrast can be realized.
At the same time, the entire system can be made lightweight and compact.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the basic structure of an active matrix type liquid crystal display device according to a first aspect of the invention.

FIG. 2 is a plan view schematically showing the basic structure of an active matrix type liquid crystal display device according to the first invention.

FIG. 3 is a cross-sectional view showing a structure in an application example of the first invention.

FIG. 4 is a cross-sectional view showing the vicinity of one pixel of the first embodiment.

FIG. 5 is a plan view showing the vicinity of one pixel of the first embodiment.

FIG. 6 is a plan view of a projection type display device using the liquid crystal display element of the present invention.

FIG. 7 is a side view of a projection type display device using the liquid crystal display element of the present invention.

FIG. 8 is a cross-sectional view showing the vicinity of one pixel of the liquid crystal display element of Example 2.

9 is a plan view showing the vicinity of one pixel of the liquid crystal display element of Example 2. FIG.

FIG. 10 is a cross-sectional view schematically showing the basic structure of the second invention.

FIG. 11 is a cross-sectional view showing the vicinity of one pixel of the liquid crystal display element of Example 3.

FIG. 12 is a plan view showing the vicinity of one pixel of the liquid crystal display element of Example 3.

13 is a partial cross-sectional view of Reference Example 1. FIG.

14 is a partial cross-sectional view of Reference Example 2. FIG.

[Explanation of symbols]

 1: Substrate 2: Active Element 3: Column Wiring (Column Electrode) 4: Pixel Electrode 5: Reflection Functional Layer 6: Third Electrode 7: Liquid Crystal Solidified Complex 8: Counter Electrode 9: Counter Substrate 10: Incident Light 102 : Base film 103: Semiconductor layer 104: Gate insulating film 105: Gate electrode 106: Interlayer insulating film 107, 108: Source / drain electrodes 309: Insulating film

Claims (4)

[Claims] 1. A plurality of row wirings and a plurality of column wirings are provided on a substrate, an active element is provided near an intersection of the row wirings and the column wirings, a gate electrode of the active element is connected to the row wiring, and a source is provided. The electrodes are connected to the column wirings, the drain electrodes are connected to the display electrodes, and the active matrix substrate is formed by forming the insulating layer so as to cover at least the row wirings, the column wirings, and the active elements, and the transparent electrodes are formed on the substrate. The liquid crystal solidified composite in which the nematic liquid crystal having positive dielectric anisotropy is dispersed and held in the solidified matrix is sandwiched between the counter electrode substrate and the counter electrode substrate,
A third electrode is formed on the insulator layer so as to cover a part or all of the row wiring, the column wiring, and the active element.
A liquid crystal display element, characterized in that the potential of the electrode is kept below the threshold of the liquid crystal solidified composite layer with respect to the potential of the counter electrode. 2. A counter electrode substrate on which a transparent electrode is formed, row wirings, column wirings, and active elements are provided near the intersections of row wirings and column wirings on the substrate, and row wirings, column wirings, active elements are provided. An active matrix liquid crystal display element comprising a liquid crystal electro-optic medium whose scattering state changes according to an electric field applied state, and an active matrix liquid crystal display element having a reflection function layer formed so as to cover the pixel display electrode. Is a transparent electrode formed on or above the reflective functional layer. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal electro-optic medium used is a nematic liquid crystal having a positive dielectric anisotropy dispersed and held in a solidified matrix, forming a scattering state in the absence of an electric field, and applying an electric field. A liquid crystal display device, which is a liquid crystal solidified composite having reduced scattering. 4. A projection type comprising the liquid crystal display device according to claim 1, a light source system, a color separation / synthesis optical system, and a projection optical system in combination. Liquid crystal display device.