JPH116999A - Manufacturing method of liquid crystal substrate, liquid crystal display element and projection type liquid crystal display device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To remove unnecessary light from a projection display. A transparent electrode having a sawtooth surface with a pitch of P and a height of d is formed on a front electrode substrate, and a reflective functional layer having a pixel length of a is formed on a back electrode substrate. G liquid crystal / resin composite 155 is sandwiched (a> P,
a> G), assuming that the average value of the angle θ (x) between the sawtooth surface and the flat surface in the effective dimension length is θ _AV , the light collection angle δ of the projection optical system (effective numerical aperture F = sin ⁻¹ δ) Satisfy θ _AV ≧ δ / 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal substrate and a projection type liquid crystal display device using a liquid crystal display element having a transmission scattering type operation mode in a reflection type configuration.

[0002]

2. Description of the Related Art As a conventional liquid crystal display device, a dynamic scattering type liquid crystal display device, a TN type liquid crystal display device and an STN type liquid crystal display device are known. However, a TN type using a polarizing plate,
The STN type has a drawback that the display becomes dark because a polarizing plate is used on the principle of operation.

Further, in recent years, a liquid crystal display device in which a liquid crystal / resin composite in which a liquid crystal and a resin are combined is sandwiched between opposed electrodes has been developed. The light scattering state and the light transmission state are controlled by providing the resin so that the refractive index of the resin substantially matches the refractive index of the liquid crystal in either the state where the voltage is applied or the state where the voltage is not applied.

The transmission-scattering type liquid crystal display element is called a dispersion type liquid crystal element, a polymer dispersion type liquid crystal element, or the like. Since a polarizing plate is not used, a bright display can be basically performed. For this reason, a bright and large projection screen can be obtained particularly when used in a projection display device.

[0005] When this transmission-scattering type liquid crystal display element is used as a reflection-type element by forming a light reflection layer on one side of the element, light travels back and forth through the modulation material layer as compared with the case of using it as a transmission-type element. Is approximately twice as long as the transmission type. As a result, a display element having high scattering ability at the time of scattering is obtained. Therefore, when this transmission-scattering type liquid crystal display element is used in a reflection type configuration, a significant difference between the transmission state and the scattering state occurs, and a high-contrast display is possible as compared with the case where the transmission type liquid crystal display element is used.

In addition, it is preferable that the light-scattering layer has the same scattering power with respect to the transmissive display element, since the light modulation layer can be formed relatively thin, and as a result, the driving voltage applied between the opposing electrodes can be reduced. Further, this transmission-scattering type liquid crystal display element is TF
When the T-active matrix driving method is adopted and an active element and a storage capacitor are formed for each pixel, the reduction in the pixel aperture ratio due to the formation of the storage capacitor is reduced by adopting a reflection type configuration, and the transmission type configuration is adopted. Compared with this, a high aperture ratio is easily obtained, and the degree of freedom in designing an active element is greatly increased.

In addition, because of the reflection type configuration, a single crystal MOS transistor formed on a Si wafer can be used as an active element and used as a reflection active matrix array substrate. That is, a display element is formed by using a Si wafer as one substrate and combining it with a transparent counter substrate.

The prior art of a reflection type liquid crystal display device using a single crystal Si-MOS transistor as an active matrix or a projection type liquid crystal display device using the same is disclosed in Li.
liquid Crystals: application
s and uses Vol. 1 (Edited b
y Birendra Bahadur: WorldS
scientific Publishing Co. R
te. Ltd. 1990, pp. 455-468), which have already been prototyped in the 1980's and are known technologies. However, the transmission scattering type liquid crystal display element at that time was of the DSM type.

Further, a liquid crystal / resin composite and a single crystal MOS-
Regarding the technology of a reflection type liquid crystal display element configured by combining an active matrix of a transistor, see, for example, JP-A-6-194690 and JP-A-8-32.
No. 8034.

As described above, when a transmission-scattering type liquid crystal display element is used in a reflection type in a projection type liquid crystal display device, higher performance can be expected as compared with a transmission type configuration. However, when used as a reflection type liquid crystal display device, device interfaces parallel to the light reflection layer exist in the optical path, and Fresnel reflected light (unwanted light component) at those interfaces is reflected by the reflection layer (display light). Component), which in particular causes an increase in dark level. As a result, the contrast ratio is degraded, so that some measure for reducing the Fresnel reflected light is required.

In particular, the influence of the residual Fresnel reflected light is remarkable at the transparent electrode interface of the front electrode substrate on the light incident side in contact with the liquid crystal / resin composite. As a measure to reduce such interface reflection, an antireflection film in which a dielectric film having a different refractive index from that of the transparent electrode film is provided at the transparent electrode interface of the front electrode substrate on the light incident side in contact with the liquid crystal / resin composite. This is described in JP-A-3-223680.

In addition, instead of forming an anti-reflection film, fine irregularities are formed at the interface of the transparent electrode to diffuse the interface reflection light and prevent the interface reflection light from being incident on the aperture stop of the projection lens, thereby causing the interface image to have an interface reflection. A configuration in which light does not overlap is described in JP-A-4-253860.

When a transmission scattering type liquid crystal display element is used as a transmission type element, one or two surfaces of a substrate sandwiching a liquid crystal layer are interposed in order to increase the backscattered light component at the time of scattering and improve the contrast ratio. Japanese Patent Laid-Open No. Hei 4
No. 318518. However, the effect of the unevenness in this conventional example is different from that in the above-described reflection mode.

However, in the conventional example employing the reflection type liquid crystal display device, there is no mention of the residual interface reflection when the projection type liquid crystal display device is constructed. Further, in the description of the examples and drawings, since only a flat transparent electrode layer is formed on a flat substrate surface, the reflected light at the interface between the substrate and the transparent electrode is superimposed on the projected image, and the contrast ratio is improved. Was not achieved.

For the same purpose as in JP-A-4-318518, when a transmission-scattering type liquid crystal display element is used, when the liquid crystal layer is scattered, scattering at the interface with the substrate is increased to improve the contrast ratio. For example, Japanese Patent Laid-Open No. 5-2721 discloses an example of a diffraction type liquid crystal panel in which a rectangular cross section is formed with an isotropic medium on at least one of the substrates facing each other with the liquid crystal layer interposed therebetween.
No. 3 publication.

[0016]

When a transmission / scattering type liquid crystal display element is used in a reflection configuration, it is necessary to cut off unnecessary reflected light to further improve display quality. In particular, in the case of the example described in JP-A-4-318518, a diffraction grating having a rectangular cross section is formed so that the zero-order light diffraction (normally reflected light) at the liquid crystal layer interface becomes maximum when the liquid crystal display element is in a scattering state. ing. Therefore, when used as a reflective liquid crystal display element in a projection display device, the regular reflection light component at the interface of the diffraction grating at the time of scattering is maximized and superimposed on the projected image, and the improvement of the contrast ratio cannot be achieved.

Therefore, in a projection type display device using a reflection type liquid crystal display device, by optimizing the configuration of the transparent electrode interface of the front electrode substrate of the liquid crystal display device, unnecessary light components superimposed on the projected image can be substantially reduced. And realizing a projected image with a high contrast ratio has been a major issue. Further, it has been difficult to achieve both high-quality projected images with good display uniformity and visibility. Further, it has been expected to realize a reflection-type liquid crystal display element which has a structure which is easy to manufacture suitable for mass production and which can be manufactured by a stable and high-yield manufacturing method.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a projection type liquid crystal optical device having a high contrast ratio and a liquid crystal display element used therefor.

That is, a liquid crystal / resin composite is sandwiched between a light source system, a front electrode substrate having a transparent electrode, and a back electrode substrate having a reflective function layer. A projection type liquid crystal display device provided with a liquid crystal display element having an uneven surface and an optically flat surface on a reflection function layer, and a projection optical system having at least one lens and one stop. Then, when the liquid crystal / resin composite is in a transparent state, after entering the liquid crystal display element from the front electrode substrate side,
The light regularly reflected by the reflection function layer passes through the aperture of the stop of the projection optical system, a display image of the liquid crystal display element is formed at a desired spatial position by a lens, and the liquid crystal / resin composite is scattered. At this time, of the light incident on the liquid crystal display element from the front electrode substrate side, a component that is reflected in the vicinity of the uneven surface and passes through the aperture of the stop of the projection optical system is 1% or less of the total incident light. And a projection type liquid crystal display device characterized by the following.

In a second aspect of the present invention, the converging angle of the projection optical system is δ (effective numerical aperture F = sin ⁻¹ δ), and the cross-sectional curve of the uneven surface that appears in the vertical cross section of the substrate surface of the liquid crystal display element is If the inclination angle of the flat surface appearing in the cross section with respect to the intersection straight line is a function of position θ (x) and the average value of θ (x) in at least the effective dimension length is θ _AV , the relationship θ _AV ≧ δ / 2 is satisfied. Is satisfied, the average value R _FR (%) of the interface Fresnel reflectance between the uneven surface and the liquid crystal / resin composite, and the inclination angle component ratio Q = 100 · [frequency (0 ≦ θ (x ) ≦ δ /
2)] / [frequency (0 ≦ θ (x) ≦ 90 °)] (%) satisfies the relationship of R _FR × Q ≦ 1%. Provide equipment.

Here, the frequency (0 ≦ θ (x) ≦ δ / 2) refers to one of the reference surfaces (the flat surface of the back electrode substrate) when measuring a surface shape exhibiting a subtle change. This is an index indicating the degree of the angle relationship of the minute area. In the case of a surface having an almost constant inclination and a steep change, for example, a saw-tooth unevenness, the numerical value of Q becomes small. Ideally, it will be zero. Conversely, in the case of a curved surface having a derivative close to a flat surface, the numerical value of Q becomes large. In the present invention, the saw-toothed uneven surface includes a curved shape having few flat portions, and includes, for example, a sine wave shape, a semicircular arc shape, and a trapezoidal shape.

The third aspect of the present invention relates to an average value R of the interfacial Fresnel reflectance between the transparent electrode of the front electrode substrate and the liquid crystal / resin composite.
_FR (%) is 5% of the wavelength of the light incident on the liquid crystal display
The projection type liquid crystal display device according to claim 1 or 2, wherein:

Further, the converging angle of the projection optical system is set to δ (effective numerical aperture F = sin ⁻¹ δ), and the cross-sectional curve of the uneven surface appearing in the vertical cross section of the substrate surface of the liquid crystal display element is defined as The average angle R _FR (%) of the interfacial Fresnel reflectance between the uneven surface of the front electrode substrate and the liquid crystal / resin composite, where the inclination angle of the flat surface appearing in the cross section with respect to the intersection straight line is defined as a function of position θ (x).
And the inclination angle component ratio Q = 100 ·
[Frequency (0 ≦ θ (x) ≦ δ / 2)] / [frequency (0 ≦ θ
(X) ≦ 90 °), wherein Q ≦ 50% is satisfied. The projection type liquid crystal display device according to claim 1, 2 or 3, is provided.

According to a fifth aspect of the present invention, the projection type liquid crystal display according to the first, second, third or fourth aspect is characterized in that the cross-sectional curve of the uneven surface appearing in the cross section perpendicular to the substrate surface is substantially saw-toothed. Provide equipment.

According to a sixth aspect of the present invention, the unevenness of the master substrate on which the fine saw-toothed unevenness is formed is transferred to the original substrate of the front electrode substrate or a component to be attached to the original substrate. Provided is a method for manufacturing a liquid crystal substrate for forming a transparent electrode film having a shape substantially correlated with a surface shape.

In a seventh aspect, the liquid crystal substrate manufactured by the manufacturing method according to the sixth aspect is used as a front electrode substrate,
An active matrix substrate is used for the back electrode substrate,
A liquid crystal display device in which a liquid crystal / resin composite is sandwiched between both electrode substrates, wherein a transparent electrode of a front electrode substrate is provided with a saw-toothed uneven surface, and a pitch P of the unevenness is a size of a pixel of a back electrode substrate. The present invention provides a liquid crystal display element which is smaller than a and the average thickness G of the liquid crystal / resin composite is smaller than the pixel size a.

In the above-mentioned invention, the pitch P of the fine irregularities on the transparent electrode surface of the front electrode substrate is smaller than the pixel size a of the back electrode substrate, and the average of the liquid crystal / resin composite is small. It is preferable that the thickness G is smaller than the pixel size a.

Further, in the invention of each of the above claims, the average pitch P and the average depth d of the fine irregularities on the transparent electrode surface of the front electrode substrate satisfy a relationship of 0.5 μm ≦ P ≦ 30 × d, The average thickness G (μm) of the liquid crystal / resin composite and the average depth d (μm) of fine irregularities on the transparent electrode surface are 20 ≦ G / d
It is preferable to satisfy the relationship of ≦ 300.

Further, in the above-mentioned inventions, the transparent electrode film formed on the fine unevenness formed on the front electrode substrate is an ITO film, and is used for transmitting incident light or projected light to the liquid crystal display element. Optical film thickness of ITO film = center wavelength λ =
It is preferable that the refractive index is n ₁ × the thickness d ₁ ≒ λ / 2.

In each of the above-mentioned inventions, the transparent electrode film formed on the fine unevenness formed on the front electrode substrate is a laminated film of a dielectric film and an ITO film having different refractive indexes. First, a dielectric film is formed on the fine irregularities,
Further comprising a structure in which the ITO film is laminated thereon, the refractive index n ₂ of the dielectric film, when the refractive index of the substrate material of the front electrode substrate was n _g, of n _1> n _2> n _g It is preferable to satisfy the relationship.

At this time, the optical film thickness of the ITO film is n ₁ × with respect to the center wavelength of the incident light or the outgoing light to the liquid crystal display element.
d ₁ ≒ λ / 2, and the optical thickness of the dielectric film = n ₂ × d ₂
It is preferable that ≒ λ / 4 or n ₂ × d ₂ ≒ 3 · λ / 4.

In the above-mentioned invention, the fine irregularities on the transparent electrode surface of the front electrode substrate are preferably in a sawtooth shape having a sharp change in shape, and are preferably formed on the back electrode substrate side. It is particularly preferable that there is almost no minute region parallel to the flat reflecting surface. It is particularly preferable that a transparent resin layer is formed on a glass substrate, and a saw-tooth shape is transferred to the transparent resin layer.

In the above-mentioned invention, a master substrate having fine saw-toothed irregularities is prepared, and a dielectric film having substantially the same refractive index as that of the front electrode substrate is formed by a CVD method. After transferring this fine saw-tooth unevenness to the resin layer of the original substrate of the front electrode substrate on which the molding resin layer is applied, a fine saw-tooth unevenness on the surface is formed by ion etching. It is preferable that the resin layer and the dielectric film layer are etched until the resin layer is exhausted while maintaining the above conditions, fine saw-tooth irregularities are formed on the dielectric film layer, and a transparent electrode film is further formed thereon.

In the invention according to claim 6 or 7, the saw-tooth unevenness on the transparent electrode surface of the front electrode substrate corresponds to the pitch of the saw-tooth unevenness after applying photoresist on the original substrate of the front electrode substrate. A mask is formed by exposing and developing the photoresist so as to have openings at the pitch, and a mask is formed. By penetrating the etching solution for dissolving the original substrate for a long time, serrated irregularities are formed on the original substrate at the photoresist interface. Then, it is preferable to form a transparent electrode film thereon after removing the remaining photoresist.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a projection type liquid crystal display device of the present invention, a liquid crystal display element having a transmission and scattering operation mode is used as a light modulating means. Then, a reflective projection type liquid crystal display device is configured by combining with other optical elements.

In this case, in the pixels in the scattering state, the light that has reached the back side without being scattered is reflected by the reflection function layer, and passes through the scattering portion in the cell of the liquid crystal display element again when returning to the optical path. Scattering results in a high light scattering rate with a thin light modulating layer.

Specifically, it is preferable to employ a liquid crystal display device using the above liquid crystal / resin composite. Because
This is because an electrically scattering state and a transmission state can be directly controlled, a bright light source can be used, and the transmittance of light during transmission can be greatly improved, so that a display with a high contrast ratio can be easily obtained.

The specific resistance of the liquid crystal / resin composite layer used in the present invention is preferably 5 × 10 ¹⁰ Ωcm or more.
Further, in order to minimize a voltage drop due to a leak current or the like and to obtain a high-definition display, it is more preferably 10 ¹¹ Ωcm or more. In this case, it is not necessary to provide a large storage capacitance for each pixel electrode.

Although there are various structures of the liquid crystal / resin composite, in the present invention, the three-dimensional network is contained in the continuous phase liquid crystal.
In particular, a structure in which a resin in the form of a hoop is formed is preferable, but the effect of the present invention can be exerted even in a structure in which a large number of liquid crystal particles are contained in the resin in the continuous phase. Liquid crystal and the resin phase is the ordinary refractive index of the liquid crystal used is the refractive index of the resin in any state at the time is applied or when no voltage is applied (n _o) or the extraordinary refractive index (n _e) and so as substantially to match Is provided.

[0040] In particular, the refractive index of the liquid crystal n _o resin (n _p)
It is preferable that these values substantially coincide with the above, and at this time, high transparency can be obtained when an electric field is applied. More specifically, n _o -0.03 <n
it is preferable to satisfy the relationship of _p <n _o +0.05.

A voltage is applied between the electrodes of the desired pixel. In this voltage applied pixel portions, the liquid crystal is arranged in parallel to the electric field direction, shows the transmission state by the n _p of the liquid crystal n _o and resin coincide, the light is transmitted in the desired pixel And it is displayed brightly on the projection screen.

[0042] The liquid crystal of the refractive index anisotropy Δn (= n _e -n _o)
Is preferably larger than a certain level in order to contribute to the scattering property and obtain a high scattering property. Specifically, Δn ≧ 0.18
Is particularly preferable, and Δn ≧ 0.20 is particularly preferable.

It is preferable to use a nematic liquid crystal having a positive dielectric anisotropy. Further, the volume fraction Φ of the liquid crystal is more preferably about 60 to 75%, particularly preferably 65 to 70%. In addition, the operating temperature range required for liquid crystals,
It is more advantageous to use the composition to satisfy various required performances such as operating voltage.

The liquid crystal / resin composite is sandwiched between a front electrode substrate and a back electrode substrate having a reflection film to form a reflection type liquid crystal display device. The effective refractive index of the liquid crystal changes according to the state of voltage application between the electrodes of the reflective liquid crystal display element, and the relationship between the refractive index of the resin phase and the refractive index of the liquid crystal phase changes. When the refractive indices are almost the same, a transmissive state (light is emitted after regular reflection) is obtained, and when the refractive indices are different, a scattering state (diffused light is emitted from the liquid crystal display element) is obtained.

The liquid crystal / resin composite used in the present invention is prepared by a photo-induced polymerization phase separation method (Photo Induced Phase).
e Separation: Abbreviated as PIPS. )
It is preferable to form with. As the material of the resin phase constituting the liquid crystal / resin composite, use of a photocurable compound as an uncured curable compound is preferable, and use of a photocurable vinyl compound containing an oligomer is particularly preferable. For example, JP-A-63-271233, 63-2780
No. 35, JP-A-3-98022.

A liquid crystal / resin composite by another method can be basically employed. In addition, the uncured mixture of the liquid crystal and the curable compound may include ceramic particles for controlling the substrate gap, plastic particles, spacers such as glass fibers, pigments, dyes, viscosity modifiers, and other adverse effects on the performance of the present invention. May be added. The higher the transmittance in the transmission state of the reflection type liquid crystal display device using the liquid crystal / resin composite, the better, and the haze value in the scattering state is 80.
% Is preferable.

When a TFT is used as an active element in the present invention, silicon is suitable as a semiconductor material. In particular, polycrystalline silicon can operate at a higher speed than amorphous silicon, can operate with a TFT having a small area, can achieve a high aperture ratio, and can provide a bright display. Also, a MOS semiconductor substrate can be used as the back electrode substrate. In this case, the driving voltage can be set higher than that of the TFT, and the cell gap can be increased to about 15 μm when driving at 15 V.

The basic configuration is as follows.
The light source system includes a light source, a condensing unit, and a first aperture stop,
The divergent light emitted from the light source is condensed on the opening of the first aperture stop by the light condensing means, and the light passing through the first aperture stop is made incident on the reflection type light modulation means, thereby forming a projection optical system. The light is condensed on the liquid crystal display element by the convex lens which is an element.

When the liquid crystal display element is in a transparent state, the light regularly reflected by the reflection function layer is again condensed by the same convex lens, and the projection optical system uses the convex lens to convert the conjugate image of the aperture of the first stop into the first. And a projection lens having a second stop having the same opening shape as the conjugate image is arranged near the conjugate image at the opening of the first stop.

FIG. 1 is a block diagram showing a basic configuration of a projection type liquid crystal display device of the present invention. Lamp 1 for light source system 1
1, a condenser mirror 12 and a first stop 13 are provided, and the projection optical system 2 is provided with a condenser lens 14, a second stop 16 and a projection lens 17.

In the configuration shown in FIG. 1, the light emitted from the lamp 11 is condensed by the condenser mirror 12, and then the divergent light that has passed through the first aperture 13 arranged near the focal point is collected. The light is condensed by the lens 14 and enters the reflection type liquid crystal display element 15, is reflected by the reflection function layer on the back side, exits to the incident side, passes through the condenser lens 14 again, and is passed through the second stop of the projection optical system 2. The light condensed and transmitted through the opening 16 is projected on a screen (not shown) by the lens 17 of the projection optical system.

The optical axis AX of the incident light is incident at an angle γ / 2 with respect to the normal to the reflection function layer of the reflection type liquid crystal display element, and the optical axis BX of the outgoing light that is regularly reflected by the reflection function layer also has an angle γ. / 2. At this time, an uneven surface is formed on the front electrode substrate side of the liquid crystal display element, and at least a unit of effective length L _O画素 20 pixels,
The above conditions are satisfied. Actually, the transparent electrode 152
This uneven surface is formed on the second stop 1.
The optical path is deflected out of position 6.

FIG. 2 is a sectional view schematically showing the structure of a reflection type liquid crystal display element 15 used in the projection type liquid crystal display device of the present invention. The liquid crystal display element 15 has a transparent electrode 15 on the inner surface.
2 and the reflective electrode film 1 on the inner surface.
The liquid crystal / resin composite 155 is sealed in an element assembled into a cell by the back electrode substrate 153 on which the 54 is formed. The transparent electrode 152 and the reflective electrode film 154
And a liquid crystal / resin composite 1
The transmission characteristics (or scattering characteristics) of the 55 change. Halftone display for an intermediate potential is also possible.

Front electrode substrate 1 on which transparent electrode 152 is formed
On the surface of 51, for example, fine saw-tooth irregularities having a pitch P (μm) and a depth d (μm) are formed as shown in FIG. The reflective electrode film 154 formed on the back electrode substrate 153 has an optically flat surface, is divided into pixel electrodes as display units, and the length of the short side is a (μm).

At this time, the average thickness of the liquid crystal / resin composite 155 is represented by G, and the angle formed by the inclined surface of the fine unevenness having the pitch P and the depth d with the flat reflective electrode film 154 is represented by θ (x). . When the liquid crystal / resin composite layer 155 is in a transparent state, incident light having an incident angle α with respect to the reflective electrode film 154 is reflected by the reflective electrode film 15.
4 is regularly reflected at a reflection angle α.

On the other hand, the state of one section of the liquid crystal display element is shown in FIG.
It was shown to. The direction of the cut surface was x, and was parallel to one side of the rectangular pixel. Here, the angle of incidence is α-θ (x) with respect to the inclined surface of the uneven surface having an angle θ (x) with respect to the flat surface of the reflective electrode film 154 (in the figure, a long portion of one saw tooth). It is. The regular reflection light on this surface forms a reflection angle α-2θ (x) with respect to the normal to the reflection electrode film 154. Therefore, the regular reflection light from the reflection electrode film 154 and the regular reflection light from the inclined surface having fine irregularities are emitted while maintaining an angle difference of 2θ (x).

Assuming that the dispersion angle of the light incident on the liquid crystal display element is φ, the average θ _AV of the inclination angle θ (x) over the entire surface is:
If the relationship of θ _AV ≧ φ / 2 is satisfied, the regular reflection light of the reflection electrode film 154 and the regular reflection light by the inclined surface of the fine unevenness are the same even when the dispersed light enters the liquid crystal display element. They are distinguished without being mixed in the angle range.

As a result, the condenser lens 14 and the projection optical system 2
The light collection angle δ defined by the opening of the second stop 16
Is set equal to the dispersion angle φ (that is, θ _AV ≧
δ / 2), the regular reflection light of the reflection electrode film 154 passes through the opening of the second diaphragm 16 and is projected on a screen (not shown) by the lens 17 of the projection optical system. Is blocked and does not reach the screen.

Actually, in the case of an inclined surface having fine irregularities with a pitch P of 100 μm or less, it is difficult to stably produce a sawtooth shape having sharp edges as shown in FIG. 2, and θ (x) <δ
Many tilt angle components of / 2 occur. Therefore, the ratio A (%) of the interface reflection light of the transparent electrode 152 superimposed on the regular reflection light of the reflection electrode film 154, which is image information, to the light incident on the liquid crystal display element is represented by the interface reflectance R _FR of the transparent electrode 152. (%) And among the inclined surfaces having fine irregularities, θ (x) <δ
/ 2 with the inclination angle component ratio Q (%).

When the liquid crystal / resin composite layer 155 is in a scattering state, in order to reduce the interface reflection light other than the scattered light of the liquid crystal / resin composite layer 155 and improve the contrast ratio of the projected image, A = R It is important that the ratio of _FR × Q be 1% or less.

For example, when the condensing angle δ = 10 °, the reflectance of the display element when the liquid crystal / resin composite layer is transparent to the incident light (the aperture ratio of the pixel electrode, the reflectance of the reflective electrode, the reflectance of the front electrode) (The total value of the transmittance of the substrate and the transmittance of the liquid crystal / resin composite layer) is 50%, and the reflectance of the display element excluding A when the liquid crystal / resin composite layer is scattered is 0.5%. , The actual display contrast ratio CR is CR = 50 /
(0.5 + A), and when A = 1%, CR = 33,
When A = 0.5%, CR = 50, and when A = 0.05%, CR = 91.

The lower the value of the interface reflectance R _FR (%) of the transparent electrode 152 is, the smaller the ratio A is, and the higher the transmittance of the front electrode substrate when the liquid crystal / resin composite layer is transparent, the higher the value. The smaller the value of the interface reflectance R _FR (%), the better.
Therefore, the interface reflectance R _FR (%) for incident light is 5
% Or less, and more preferably 2% or less.

Further, since the thickness G of the liquid crystal / resin composite layer is distributed within the range of the pitch P according to the depth d of the inclined surface of the fine unevenness, the driving voltage of the liquid crystal / resin composite layer is increased. And scattering power differ within the pitch. As a result, when the liquid crystal display element is enlarged and projected, display unevenness occurs. Therefore, it is preferable that the pitch P be smaller than the short side length a of one pixel in order to prevent display unevenness across display pixels.

Since the inclination angle θ roughly defined by the depth d and the pitch P of the inclined surface of the fine unevenness is preferably 2 ° or more, it is preferable that the relationship of P ≦ 30 × d is satisfied. Further, it is preferable that the relationship of P ≦ 10 × d is satisfied.

When the depth d of the inclined surface of the fine unevenness is a relatively large value according to the thickness G of the liquid crystal / resin composite layer, the driving voltage of the liquid crystal / resin composite layer within the pitch P is reduced. A problem arises in that the display is distributed and non-uniform, and the slope of the applied voltage-reflectance characteristic becomes slow, so that the operating voltage width and the driving voltage are substantially increased. Therefore, G and d
Is preferably in the range of 20 ≦ G / d.
However, the thickness G of the liquid crystal / resin composite layer is usually 4 to 30 μm.
In the case of low voltage driving of about 4 to 15 V, G is preferably about 6 to 20 μm.

In particular, when the in-plane distribution of the thickness G of the liquid crystal / resin composite layer due to the variation in the depth d of the inclined surface of the fine unevenness is large, the liquid crystal / resin composite is used as the light modulating layer. Since the applied voltage-reflectance characteristic of the liquid crystal display element having a reflective function layer on the back surface is geometrically distributed, display unevenness is caused in a halftone gradation display. If so, the effect can be suppressed.

Further, in order to function as an inclined surface with respect to incident light, it is necessary that the pitch P of the fine uneven inclined surface is equal to or more than the wavelength of the incident light. Therefore, specifically, it is preferable that 0.5 μm ≦ P and 0.2 μm ≦ d.

In the above description, since the light beam inside the liquid crystal display device and the light beam outside the liquid crystal display device, that is, the light beam in the air, are refracted according to the refractive index of the front electrode substrate, the angle changes according to the Snell's law. The description of the difference is omitted for simplicity.

Since the back electrode substrate 153 has electrodes and has a reflecting function by means of a reflecting film, it may be made of any of glass, plastic, metal, ceramics, semiconductor and the like. Since this back electrode is used after being patterned as the pixel electrode 154, an active element such as a TFT, a thin film diode, a MIM, or a MOS transistor is provided and connected as necessary.

Instead of the reflective electrode film, a combination of a back electrode and a reflective film may be used. As the reflective film, a translucent dielectric thin film having a relatively high refractive index and a translucent dielectric film having a relatively low refractive index are used. A dielectric multilayer film in which a body thin film is laminated may be used. The dielectric multilayer film is made of a low-refractive-index translucent dielectric thin film such as SiO ₂ , MgF ₂ , Na ₃ AlF ₆ , and TiO ₂ , ZrO ₂ , T
a ₂ O ₅ , ZnS, ZnSe, ZnTe, Si, Ge,
It has a structure in which high-refractive-index translucent dielectric thin films such as Y ₂ O ₃ and Al ₂ O ₃ are alternately laminated, and the material, film thickness, The number of layers is different, and the design flexibility is wider than that of metal films.

When an active element is formed for each of the back electrodes, it also functions as a light shielding film so that light incident on the reflective liquid crystal display element does not directly reach the active element. As a result, even when an active element having a large photoconductive effect, such as amorphous silicon, is used, generation of a photoinduced current can be reduced without providing a separate light-shielding layer.

In the transmissive pixel portion of the reflection type liquid crystal display element, light is transmitted, and after being regularly reflected by the reflection film, is emitted to the air side. Since this straight light becomes light passing through the second aperture 16 which is a device for reducing diffused light, it is displayed brightly on the projection screen.

On the other hand, light is scattered in the scattered pixel portion and emitted as diffused light. Most of this light will not pass through the second stop 16, which is a device that reduces diffused light, and will appear dark on the projection screen.

In the present invention, since the reflection type liquid crystal display element is used, light that reaches the rear side without being scattered at the pixel portion in the scattering state is reflected and passes through the scattered portion again. As a result, a high scattering rate can be obtained in the thin liquid crystal / resin composite layer 155. In addition, when the same scattering power is used for the transmission type liquid crystal display element, the driving voltage can be reduced because the liquid crystal / resin composite layer can be made thin.

FIG. 3 shows a projection type liquid crystal display device 200 according to the present invention.
FIG. 3 is a schematic plan view of FIG. FIG. 4 is a schematic side view of the projection type liquid crystal display device 200 of the present invention. 3 and 4, the light emitting portion of the lamp 11 is disposed at the first focal position of the elliptical mirror 12, and the light emitted from the lamp 11
After the light is focused near the second focal point, the light that has passed through the first aperture stop 13 arranged at the second focal position is focused by the plano-convex lens 14 and enters the reflective liquid crystal optical element 15, The second device is a device that is reflected by the back side, exits to the incident side, passes through the plano-convex lens 14 again, is collected, and reduces diffused light.
And is projected on a screen (not shown) by a lens 17 of a projection optical system.

In FIG. 4, the conical prism 18 arranged near the second focal point of the elliptical mirror 12 is
5 has the effect of making the distribution of the light irradiated to 5 uniform and improving the light use efficiency (for the operation and configuration of the conical prism, refer to JP-A-7-134295).

The plane side of the plano-convex lens 14 is the liquid crystal display element 1
No interface reflection occurs because the plano-convex lens 14 and the coupling oil having substantially the same refractive index as the glass substrate are joined to the light incident side glass substrate No. 5. The material of the plano-convex lens 14 used here may be glass or plastic.
It is preferable that the refractive index is substantially equal to 51 in order not to cause Fresnel reflection at the bonding interface.

The shape of the convex surface is generally a spherical surface, but is preferably an aspherical surface in order to improve the resolution of the projected image and the aberration when combined with the projection lens.
In addition, the thickness of the plano-convex lens may be reduced by making it into a Fresnel shape, and the weight may be reduced.

The light source system of the present invention is shown in FIGS. 3 and 4 using an ellipsoidal mirror as a condensing mirror. However, a light source system appropriately combining a parabolic mirror, a spherical mirror, a lens, and the like may be used. Can be used as a system. Examples of the lamp include a halogen lamp, a metal halide lamp, a xenon lamp, and the like. Further, a cooling system is added to this light source system, or an infrared cut filter, an ultraviolet cut filter, or the like is used in combination.

The convex conical prism 18 may have its convex surface disposed on the light source side, or may use a concave conical prism instead. By using such an optical element, the illuminance uniformity and light use efficiency of the projection light are improved.
Further, optical elements such as a lens array integrator, a rod integrator, a single lens, and a diffusion plate may be arranged.

When the incident light separated into color light is made incident on a plurality of reflective display elements, a light source of three colors may be prepared from the beginning, or may be separated by a dichroic mirror, a dichroic prism or the like. Specifically, FIGS. 3 and 4
If applied to the device of the above, the reflection type liquid crystal display element 15
The color separation / combination system 4 is arranged between the light source system 1 and the lens 17 of the projection optical system, and three reflective display elements are arranged for each color light of RGB.

The projection type liquid crystal display device 3 configured as described above
FIG. 5 is a schematic plan view of FIG.
Shown in In this example, a dichroic mirror 41 transmitting R reflection and GB and a dichroic mirror 4 transmitting B reflection and G are used.
In the two-panel configuration, the incident white light from the light source system is color-separated into RGB, and each of the RGB liquid crystal display elements 15R, 15R.
The RGB reflected lights from G and 15B are color-combined. Note that R or Red indicates color light in a red region in the visible light region, G or Green indicates color light in a green region, and B or Red
Alternatively, Blue indicates color light in a blue region.

In FIG. 6 (the plano-convex lens 14G and the liquid crystal display element 15G are shown in the cross section of FIG. 6), the plano-convex lenses 14R, 14G, which are joined to the liquid crystal display elements 15R, 15G, 15B having a reflection type configuration. 14B has an eccentric lens configuration whose center of rotation is located outside the display surface of the reflective display element.

As a result, since the convex surface of the plano-convex lens parallel to the reflective function layer of the reflective display element does not exist in the display element, the residual interface reflected light on the convex surface is different in direction from the regular reflected light on the reflective functional layer. Differently, it does not pass through the opening of the second stop 16 of the projection lens. Therefore, even if there is residual reflection on the convex surface of the plano-convex lens, it does not overlap with the projected image.

When an image is projected on a screen by a display element having fine pixels as a liquid crystal display element, a projection lens having a resolution capable of decomposing display pixels to every corner of the display surface is required. It is composed of two lenses of different materials and shapes. In such a case, the second
The relative position of the stop 16 is a pupil position in the projection lens, that is, the first stop 1 formed by the plano-convex lens 14.
It is preferable that the aperture shape is set at the conjugate image position of 3 so as to substantially coincide with the conjugate image of the aperture shape of the first diaphragm 13.

[0086]

In the present invention, a reflection type liquid crystal display element is formed by using a liquid crystal / resin composite, so that a high scattering characteristic can be obtained even with a liquid crystal / resin composite having a small thickness, and a high contrast is obtained as a characteristic of the element itself. The ratio is obtained.

In addition, since optimized fine saw-toothed irregularities are formed on the surface of the front electrode substrate on which the transparent electrode is formed, and the interface reflectance around the transparent electrode is reduced, The influence of the interface reflection light superimposed on the projection image is slight, and a high contrast ratio can be obtained as a projection type liquid crystal display device.

[0088]

【Example】

(Embodiment 1) A sectional shape of a reflection type liquid crystal display element used in a projection type liquid crystal display device according to a first embodiment of the present invention will be described with reference to FIG. Pixel shape: one side length a = 40 μm
Is a reflection type liquid crystal display element having a display diagonal length of about 2 inches, which is composed of 768 pixels vertically and 1024 pixels horizontally. The cross section in FIG. 1 is parallel to one side of a rectangular pixel. The cutting direction is defined as _xo .

In the first embodiment, 768 square pixels × 1 horizontal pixel having a side length a = 40 μm are used as a reflection type liquid crystal display element.
The active matrix has a display diagonal length of about 2 inches using a polycrystalline Si TFT as an active matrix.

An active matrix substrate having a gate wiring, a source wiring, and a polycrystalline Si-TFT formed for each pixel on a glass substrate is coated with a flattening film, and a contact hole is formed in the flattening film. Is formed and patterned to make contact between the drain electrode of the TFT and the aluminum reflective electrode. At this time, the aperture ratio of the reflective electrode in the pixel is 80%.
It is.

In order to obtain a high reflectivity of 90% or more in the reflective electrode, a silver (Ag) film may be used in place of the aluminum film, and a dielectric film having a different refractive index is laminated on the aluminum film to increase reflection. It may be a film.

The front electrode substrate is made of glass, and has fine saw-toothed irregularities having a pitch P of about 2 to 6 μm and a depth d of about 0.3 to 1 μm on the surface. ITO is deposited.

Such fine irregularities are initially formed by using a diamond ultra-precision machining machine called a ruling engine, which is used when fabricating a blazed diffraction grating, and having a pitch P of irregularities and a sawtooth having a depth d. A master plate having irregularities is manufactured.

Unlike the case where a diffraction grating is manufactured, the unevenness does not need to be precisely the same shape processing at equal intervals, but may be within the range of the shape conditions described above. Further, the master substrate may be a flat plate having sawtooth-shaped irregularities formed thereon, or may be a cylindrical roller having a rotating surface having sawtooth-shaped irregularities formed thereon.

As a method of forming the irregularities on the front electrode substrate, a method of pressing the master substrate directly on the heated glass substrate to transfer the irregularities, or forming a thin film of a transparent resin on the glass substrate and forming the irregularities on the resin. A method of transferring, or a method of laminating a resin film on which unevenness is transferred on a glass substrate can be considered. This technique is shown in FIGS.

In consideration of productivity, it is preferable to form unevenness via a transparent resin that can be transferred at a lower temperature. At this time, the difference between the refractive index of the transparent resin used and the refractive index of the glass substrate is 0.1 or less. Preferably, there is. Examples of resins that can be used as optical materials include acrylic resins, polycarbonate resins, styrene resins, and polyolefin resins. FIG. 10 shows a master substrate 170, a front electrode substrate 151, and a transfer layer 160 made of an acrylic resin.

The glass substrate to which the resin is attached has a refractive index of 1.52. The difference in the refractive index of the resin with respect to the glass substrate is within about 0.15, preferably 0.10.
Set within. A desired refractive index value can be obtained by adjusting the composition of the resin. At this time, the smaller the difference in refractive index, the more the reflectance between the glass substrate and the resin film can be suppressed.

In order to form a thin film of a transparent resin on a glass substrate and transfer irregularities to the resin, a solution of a thermoplastic resin is applied to the glass substrate, the solvent is dried, and then heated to a temperature equal to or higher than the glass transition temperature of the applied resin. There is a method of transferring the concavities and convexities by pressing the prepared master substrate, and a method of injecting and curing an uncured resin composition curable by heat or light between the glass substrate and the master substrate to transfer the concavities and convexities.

As a method of transferring the irregularities to the resin film first, the irregularities are transferred between a cylindrical roller having irregularities formed by heating a thermoplastic resin film at a temperature higher than the glass transition temperature of the resin and a smooth roller. And a method in which an uncured resin composition curable by heat or light is applied to a master substrate having irregularities and cured to transfer the irregularities. Finally, an ITO film is formed on the surface of the resin to which the fine irregularities have been transferred to obtain a front electrode substrate.

At this time, in order to reduce the value of the reflectance R at the interface of the ITO film, it is necessary to make the ITO light center wavelength .lambda.
The optical thickness (refractive index × film thickness) of the film is preferably about λ / 2. For example, in the case of Green light of λ = 540 nm, since the ITO refractive index is about 1.8, the film thickness is about 150.
If it is assumed to be nm, it is 0.5 for light in the wavelength region of 540 nm.
% Or less.

The problem with this configuration is that, for example, a wavelength of 400 to 480 nm other than λ (Green wavelength range),
Since the antireflection condition is not satisfied in the Red wavelength region of 00 nm or more, the reflectance R increases and the transmittance of the front electrode substrate decreases. Therefore, when white light with a center wavelength λ of about 540 nm is incident, an ITO film having an optical film thickness of λ / 2 is formed, and when the incident light is separated into three colors of RGB, the center wavelength λ of each color is set to On the other hand, ITO having different optical film thicknesses may be separately formed.

As a configuration for reducing such wavelength dependence, a multilayer antireflection film having an ITO film as a component may be used. For example, the refractive index of a glass substrate,
_g, the refractive index of the ITO film when the n _1, its refractive index n ₂ as a dielectric film, a dielectric film satisfying the relation of n _g <n ₂ <n ₁ between the glass substrate and the ITO film Form.

Specifically, n _g = 1.5, n ₁ = 1.8
In the case of １1.9, n ₂ = approximately 1.6.
The film may be formed by the method D under the condition that the refractive index of the SiON film is about 1.6. Alternatively, Al ₂ O ₃ may be formed by a vacuum evaporation method or a sputtering method. The optical film thickness of each film thickness at this time is n ₁ × d _{1 with} respect to the center wavelength λ of the incident light.
= Λ / 2, n ₂ × d ₂ = λ / 4 or n ₂ × d ₂ =
It may be set to 3 · λ / 4. As a result, a relatively flat spectral reflectance characteristic of 0.5% or less can be obtained in the wavelength region of visible light, so that the same film configuration is used as an anti-reflection transparent electrode film in the case of white light incidence or RGB color light incidence. it can. The multilayer structure of the antireflection transparent electrode film is not limited to the above structure, and various combinations of the number of layers, the refractive index value, and the optical film thickness are used.

Using the front electrode substrate and the back electrode substrate thus prepared, empty cells having an average gap G = 10 μm were prepared, and the liquid crystal and the uncured resin composition (acrylic monomer and acrylic oligomer) were used. And then irradiating ultraviolet rays to form a liquid crystal / resin composite by a photoexcitation polymerization phase separation method. FIGS. 3 and 4 show the reflection type liquid crystal display element manufactured in this manner, which is combined with other optical members.
A projection display device having the configuration shown in (1) is prepared.

The plano-convex lens 14 used in this embodiment is a BK7 having a plano-convex spherical shape with a focal length f = 120 mm and a rectangular shape having a length of 40 mm and a width of 45 mm. A black paint is applied to the cut surface of the plano-convex lens so that light incident on the side surface is absorbed. Further, an antireflection film for a visible wavelength region is formed on the convex surface. The display side shape of the plano-convex lens 14 is 30.5 mm × 40.
The liquid crystal display element 15 is 6 mm long and has a diagonal length of 2 inches.

The conical prism 18 and the first stop 13 are installed at the second focal position of the elliptical mirror 12, and the above-mentioned optical components are arranged as shown in FIGS. The first stop 13 is an iris stop whose opening diameter is variable. Further, the reflected light of the liquid crystal display element is condensed by the plano-convex lens 14 and the second stop 1 is located at a position where an image of the opening of the first stop 13 is formed.
6 is set so that its opening coincides with the image of the opening of the first diaphragm 13. The light transmitted through the opening of the second stop 16 is projected on the screen through the projection lens 17.

The second stop 16 may be arranged separately from the projection lens 17, but is preferably arranged at the pupil position of the projection lens 17. Assuming that the aperture diameter of the first aperture 13 is a and the aperture diameter of the second aperture 16 is b, the dispersion angle Φ and the projection angle of the incident light on the liquid crystal display element are projected using the focal length f of the plano-convex lens 14. The converging angle δ indicating the directivity of light is defined by Equation 1. Here, the aperture diameters a and b of the first aperture stop 13 and the second aperture stop 16 are simultaneously adjusted so that φ = δ.

[0108]

Tan (φ) = a / f tan (δ) = b / f

As the light source 11, a discharge light emitting metal halide lamp is used. Table 1 summarizes the contrast ratios of the projected images in such a configuration with respect to the condensing angles δ = 5 ° and 10 °. The table also shows the driving voltage, the saturation reflectance, and the dark reflectance of the reflective display element.

In the first embodiment, a case is described in which a front electrode substrate in which an ITO film is formed to a thickness of about 150 nm as a transparent electrode on the fine sawtooth-shaped uneven surface is used. Comparative Example 1 describes the case where the transparent electrode surface of the front electrode substrate of the reflection type liquid crystal display element was flat and the front electrode substrate on which an ITO film was formed to a thickness of about 75 nm was used as the transparent electrode.

Further, after the transparent electrode surface of the front electrode substrate of the reflection type liquid crystal display element was polished with a # 500 alumina abrasive to form rough irregularities on the surface, an ITO film of about 150 nm was formed as a transparent electrode. The case where the front electrode substrate was used was described in Comparative Example 2.

The saturation reflectance R _ON is a reflectance in a transparent state by applying a sufficient electric field to the liquid crystal / resin composite layer, and the driving voltage V ₉₀ is 90% of the saturation reflectance R _ON . The drive voltage at which the reflectivity is obtained, and the dark reflectivity R _OFF is the reflectivity in a scattering state where no electric field is applied to the liquid crystal / resin composite layer,
The contrast ratio CR is calculated by R _ON / R _off .

[0113]

[Table 1]

Therefore, a high saturated reflectance R _ON and a low dark reflectance R _OFF can be obtained with the driving voltage maintained at a low voltage by the configuration of the first embodiment, so that a bright and high-contrast projected image is achieved.

Further, in the configuration of Comparative Example 2, in the halftone projected image, the liquid crystal / liquid crystal caused by the rough uneven shape of the front electrode substrate was used.
Irradiance unevenness corresponding to the gap unevenness of the resin composite occurs, which is a problem in gradation display.

In this embodiment, an example is shown in which a discharge light emitting metal halide lamp is used as a light source.
An ultra-high pressure mercury lamp, a xenon lamp, an electrodeless microwave discharge lamp, a filament light emitting halogen lamp, or the like may be used.

The transmission / scattering type display element used in the present invention is:
Any flat display element that can be in a transmission state or a scattering state depending on the voltage application state can be used. In particular,
A liquid crystal display element of DSM may be used, or another scattering type display element such as an element in which fine needle-like particles are dispersed in a solution and transmission scattering is controlled by a voltage application state may be used. Materials other than the liquid crystal element can be used. Also, the driving method is not limited to the active matrix method, and other methods such as passive driving and static driving may be used.

In a projection type liquid crystal display device, as described above, an image of a display element is usually projected and formed on a screen separately provided by a projection lens as described above. In this case, even if the front projection type (the observer is positioned on the projection type display device side with respect to the screen and sees), the rear projection type (the observer is positioned on the side opposite to the projection type display device with respect to the screen). To see).

The reflective electrode of this reflective display element can be a solid electrode on the entire surface, or a projection display apparatus that is a transmissive display element with simple electrode patterning, and can be used as an illumination device. For example, by arranging the apparatus shown in FIGS. 3 and 4 in such a configuration and embedding it in a wall, a ceiling, or the like, light can be adjusted at high speed without changing the color.

In this embodiment, in order to realize color display, an RGB mosaic color filter is formed for each pixel electrode of the transmission-scattering type liquid crystal display element 15 having a display surface composed of reflective display pixels. A color image may be formed by applying RGB image signal voltages to each color pixel electrode.

(Example 2) A method different from the method for forming fine unevenness of the front electrode substrate in Example 1 is employed in the following examples. Please refer to FIG. First, as a final transfer layer 161, a SiON film having a refractive index substantially equal to the glass substrate refractive index _ng = 1.5 is formed on the surface of the front electrode substrate glass substrate 151 having a flat surface by a CVD method. Form a 2 μm film. Since SiON has a composition in which SiO ₂ having a refractive index of about 1.46 and SiN having a refractive index of about 1.7 are mixed, CVD is performed.
An arbitrary refractive index film having a refractive index of 1.46 to 1.7 can be formed depending on the film forming conditions.

Next, a photoresist used for ordinary photo-etching is uniformly applied as a first transfer layer 162 on the SiON film to a thickness of about 1 to 2 μm, and then baked to a certain degree. Further, the master substrate 1 in which the same fine saw-tooth shape as in Example 1 was engraved on the photoresist layer.
By pressing using 70, the fine saw-tooth shape is transferred to the first transfer layer 162 which is a photoresist layer.

The substrate on which the SiON layer and the photoresist layer thus obtained are laminated is subjected to surface etching by an ion etching method. At this time, the etching rate of the SiON and the etching rate of the photoresist become substantially the same, and the etching is performed until the photoresist disappears under the etching conditions of strong anisotropy,
The fine saw-tooth shape imprinted on the master substrate is transferred to the final transfer layer 161 made of a SiON layer.

In this way, a fine sawtooth-shaped SiON layer is formed on a glass substrate, and a transparent electrode film is formed thereon, whereby a front electrode substrate can be manufactured. Since the uneven layer is not resin but SiON compared to the first embodiment,
High reliability can be maintained in terms of durability such as heat resistance.

In the above description, a photoresist is used as the first transfer layer 162 for first transferring the fine sawtooth shape of the master substrate. However, any material can be used as long as it can transfer the fine shape of the master substrate and perform ion etching. The final transfer layer 161 may be made of a material other than SiON as long as the material has a refractive index similar to that of the substrate glass and can be ion-etched.

The first transfer layer 162 and the final transfer layer 16
The ion etching rates of one need not be the same.
When the rate of the first transfer layer 162 is faster than that of the final transfer layer 162, the depth becomes shallower and the slope is gentler than that of the fine sawtooth shape of the master substrate. Has a deep and deep slope compared to the fine saw-tooth shape of the master substrate, so that the final transfer layer 161 and the first transfer layer 162 are finally adjusted by adjusting the difference between the etching rates. The required uneven shape can be arbitrarily adjusted.

(Embodiment 3) A forming method different from the method for forming fine unevenness of the front electrode substrate in the embodiment 1 and the embodiment 2 will be described in the following embodiment. After coating and curing a photoresist on the glass substrate plane of the front electrode substrate, a lattice pattern having a lattice unit pitch of about 6 μm and an opening of about 2 μm × 2 μm is formed by exposing and developing the photoresist.

Next, the glass is eroded from the opening of 2 μm × 2 μm by using the photoresist as a mask by penetrating the glass substrate for a long time into an HF etching solution that dissolves the glass substrate, and the lower surface of the photoresist is also eroded by overetching.
As a result, fine irregularities having a pitch corresponding to the lattice unit pitch are directly formed on the glass substrate. In this case, although a hemispherical uneven shape is formed, most of the shape is a fine inclined surface, so that it is effective as a diffuse reflection surface. Next, after removing the remaining photoresist, a transparent electrode film is formed thereon to complete the front electrode substrate.

(Embodiment 4) In Embodiment 1, an example in which the reflection type liquid crystal display element 15 is used alone has been described. However, full-color display is performed using a plurality of reflection type liquid crystal display elements 15 for each color. Can also. When a plurality of reflective liquid crystal display elements are provided for each color, a configuration may be made such that the colors are synthesized by a dichroic mirror or a dichroic prism and then projected, or the colors are synthesized individually on the screen. However, it is advantageous to project the image after combining the colors, since the number of optical axes becomes one, so that the device is small and needs to be carried.

FIG. 5 is a schematic plan view showing the configuration of the projection display apparatus 300 when three transmission / scattering display elements (15B, 15G, 15R) are used for each of the RGB colors, and FIG. As shown in FIG. Here, the red wavelength light is reflected and G
A flat dichroic mirror 41 that transmits light of blue and blue wavelengths and a green dichroic mirror 41 that reflects light of blue wavelengths
The flat dichroic mirror 42 transmitting the wavelength light is arranged so that the incident angle is 30 ° with respect to the optical axis of the incident light, and the dichroic mirrors 41 and 42 are arranged at an angle of 60 °. .

Then, the reflective liquid crystal display element 1 for Red
5R and eccentric plano-convex lens 14R are dichroic mirror 4
The reflection type liquid crystal display element 15B for blue and the eccentric plano-convex lens 14B are arranged at a plane symmetric position with respect to the reflection surface of the dichroic mirror 42. With such a configuration, the dichroic mirrors 41 and 42 can be commonly used as a color separation system and a color synthesis system, so that the size can be easily reduced.

By adopting an RGB three-plate reflective liquid crystal display device configuration using such a flat dichroic mirror, the color purity of RGB is maintained as compared with the single-plate reflective display device configuration of the first embodiment. A projection type color display device with high light use efficiency can be realized as it is.

Fifth Embodiment In the first to fourth embodiments, the side length a of the square pixel a = 40 μm, 768 × 10 pixels.
24, polycrystalline Si-TFT, display diagonal length about 2 inches, but in this example, as a reflection type liquid crystal display element,
A reflection type liquid crystal display element having a display diagonal length of about 1 inch, in which a square pixel having a side length of a = 20 μm is composed of 768 pixels vertically × 1024 pixels horizontally and using a single crystal Si MOS transistor as an active matrix. Used.

As for the reflective pixel electrode, an insulating film is formed on the active matrix substrate, a contact hole is formed in the insulating film, and then an aluminum film is formed and patterned. In order to make the aluminum reflective electrode an optical mirror surface, chemical polishing (CMP: chemical mechanical polishing) is performed. Alternatively, after the underlying insulating film is planarized by CMP, an aluminum reflective electrode is formed and patterned. Further, a dielectric film is laminated on the aluminum surface to form a reflection-enhancing film.

The aperture ratio of the reflective electrode manufactured in this way to the pixels is about 90%, and the reflective electrode can have a reflectance of 95% or more. A reflective liquid crystal display element is manufactured in the same manner as in Example 1 by combining the front electrode substrate and the back electrode substrate.

When the reflection type liquid crystal display elements 15R, 15G, and 15B manufactured as described above are used as a three-panel projection display apparatus using each of RGB wavelengths, the two sheets used in the third embodiment are used. In the flat-plate dichroic mirrors 41 and 42, it is difficult to match the 20 μm pixels of each of the RGB panels without a pixel shift due to the effect of astigmatism caused by the transmission through the glass substrate and the flatness accuracy of the mirror surface.

Therefore, in the case of such a display definition, a color separation / combination prism in which a prism having a plurality of dichroic mirror surfaces is bonded using an adhesive having the same refractive index as the prism material is used. In this embodiment, 4
The trapezoidal prisms are joined to form a projection display device 400 in which the color separation / combination prism 50 is arranged as shown in the plan view of FIG. 7 and the side view of FIG.

Here, the light of Blue wavelength is reflected and Gre
The dichroic mirror surface 41 transmitting the en and Red wavelength light and the dichroic mirror surface 42 reflecting the Red wavelength light and transmitting the Green wavelength light such that the incident angle with respect to the optical axis of the incident light is 30 °. The shapes of the prisms 51, 52, 53, 54 are processed so that the dichroic mirror surfaces 41 and 42 form an angle of 60 °,
A dichroic mirror is formed on the inclined surfaces of the prisms 51 and 53.

The prisms 52 and 54 are symmetrical with respect to the dichroic mirror surface 41,
And 54 are symmetrical with respect to the dichroic mirror surface 42. Further, an anti-reflection film having a residual reflectance of 0.1% or less at each wavelength is formed on the light entrance / exit surface of the prism corresponding to each of the RGB reflective display elements. With such a configuration using the color separation / combination prism 50, the plane accuracy of the dichroic mirror surface is maintained and there is no astigmatism.

When the incident angle on the dichroic mirror surface is 30
In the case of °, in the case of the prism-joined configuration of the present embodiment, the polarization dependence of the spectral characteristics of the dichroic mirror increases as compared with the flat dichroic mirror, and the RGB color purity tends to deteriorate.

As a countermeasure against this problem, a filter for reducing the wavelength of light between Blue and Green, for example, 495 to 510 nm, between the color separation / combination prism 50 and the light source system 1 or a filter between Green and Red is used. Wavelength light, for example, 5
This can be improved by arranging a filter for dimming 70 to 595 nm.

As another countermeasure, a λ / 4 retardation plate corresponding to each of the RGB main wavelengths λ is adhered to the light entrance / exit surface of the prism corresponding to each of the reflective display elements for RGB, and then the residual light at each wavelength is adhered. By forming an anti-reflection film having a reflectance of 0.1% or less on the surface of the retardation plate, the dichroic mirror spectral characteristics of any of the SP-polarized light is selected, so that the color purity is improved.

In this embodiment, a configuration is shown in which a plano-convex lens is joined to each of the RGB reflection type liquid crystal display elements.
The plane of the plano-convex lens is joined to the light entrance / exit surface of the prism corresponding to each of the reflective liquid crystal display devices for RGB, and the residual reflectance at each wavelength is 0.1 at the air interface of the front electrode substrate of the display device.
% Or less.

In this embodiment, the light emitted from the lamp condensed by the elliptical mirror 12 at the opening of the first aperture 13 is deflected at right angles by a cold mirror 19 disposed below the projection lens 17. ing. With such a configuration, the interference arrangement between the projection lens and the elliptical mirror is avoided.

(Embodiment 6) The color separation / combination prism 50 of Embodiment 5 has a configuration in which all four types of prisms 51, 52, 53 and 54 are adhered and no gap is provided in the air layer. An example of a prism configuration in which an air layer gap is provided on the dichroic mirror surface 41 of the separation / combination prism will be described below.

A color separation / combination prism 60 different from that of the fifth embodiment
And the same plano-convex condensing lens 14B for RGB as in the fifth embodiment,
14G, 14R and reflective display elements 15R, 15G, 15
FIG. 9 is a partial plan view showing an arrangement state of the projection type liquid crystal display device 500 using B. Other configurations such as a light source system and a projection lens are the same as those in the fifth embodiment, and thus are not shown.

The dichroic mirror surface 41 reflects the blue wavelength light and transmits the green and red wavelength light, and the prisms 61 and 62 are processed so that the incident angle with respect to the optical axis of the incident light is 25 °. Rear prism 61
Is formed on one side.

The dichroic mirror surface 42 reflects the Red wavelength light and transmits the Green wavelength light, and after the prism 62 and the prism 63 are processed so that the incident angle with respect to the optical axis of the incident light becomes 13 °, A film is formed on one surface of the prism 62. Such three types of prisms 61, 62, 6
3 constitutes the color separation / combination prism of this embodiment.

The color separation / combination prisms of the fifth embodiment and the fifth embodiment take in an image of white natural light by a single image pickup lens, separate the colors into three colors of RGB, and detect them by three kinds of image pickup devices. The optical element has substantially the same function and configuration as a conventionally used color separation prism.

The prism 62 and the prism 63 are bonded by applying a sealing material mixed with a gap adjusting material to the prism surfaces facing each other so as to maintain a gap of about 5 to 50 μm on the dichroic mirror surface 41, thereby joining the air. A layer is formed. An anti-reflection film is formed on the interface between the prism 62 and the air layer. In addition, each RG
An anti-reflection film is formed on the prism surface through which the B wavelength light enters and exits, as in the fifth embodiment.

The prism 61 and the prism 63 are joined to each other using an adhesive having the same refractive index as in the fifth embodiment. With such a configuration, of the incident light, Blu reflected by the dichroic mirror surface 41
The e-wavelength light is totally reflected at the interface with the air on the light incident side of the prism 1 and condensed by the plano-convex lens 14B to the reflective display element 15B for blue. Of the light transmitted through the dichroic mirror surface 41, the dichroic mirror surface The Red wavelength light reflected at 42 is totally reflected at the interface between the prism 62 and the air layer formed between the prism 63 and is reflected by the plano-convex lens 14.
By R, the light is condensed on the reflective liquid crystal display element 15R for Red.

By introducing such a total reflection surface in the air layer, the prism shape can be devised so that the incident angle of the incident light on the dichroic mirror surface 41 and the dichroic mirror surface 42 becomes 30 ° or less. , 42 are reduced in polarization dependence. As a result, a color separation / combination prism having high RGB color purity and low light loss can be obtained.

Further, the color separation / combination prism is smaller than that of the fifth embodiment. The present invention is also applicable to various applications within a range that does not impair the effects of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first configuration example of a projection type liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of a reflective display element used in the projection type liquid crystal display device of the present invention.

FIG. 3 is a plan view showing a first configuration example of a projection type liquid crystal display device of the present invention.

FIG. 4 is a side view showing a first configuration example of the projection type liquid crystal display device of the present invention.

FIG. 5 is a plan view showing a second configuration example of the projection type liquid crystal display device of the present invention.

FIG. 6 is a side view showing a second configuration example of the projection type liquid crystal display device of the present invention.

FIG. 7 is a plan view showing a third configuration example of the projection type liquid crystal display device of the present invention.

FIG. 8 is a side view showing a third configuration example of the projection type liquid crystal display device of the present invention.

FIG. 9 is a plan view showing a part of a fourth configuration example of the projection type liquid crystal display device of the present invention.

FIG. 10 is an explanatory view showing the production of the uneven surface of the front electrode substrate by the first transfer method.

FIG. 11 is an explanatory view showing the manufacture of the uneven surface of the front electrode substrate by the second transfer method.

[Explanation of symbols]

1: Light source system 2: Projection optical system 4: Color separation / combination system 11: Light source 12: Elliptic mirror 13: First aperture stop 14, 14R, 14B, 14G: Condensing lens 15, 15B, 15G, 15R: Liquid crystal display Element 16: Second aperture stop 17: Projection lens 18: Conical prism 19: Cold mirror 41, 42: Dichroic mirror 50, 51, 52, 53, 54, 60, 61, 62, 6
3: prism 151: front electrode substrate 152: transparent electrode 153: back electrode substrate 154: reflective functional layer (reflective electrode) 155: liquid crystal / resin composite

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Shinya Tahara 1150 Hazawacho, Kanagawa-ku, Yokohama-shi

Claims (7)

[Claims] A liquid crystal / resin composite is sandwiched between a light source system, a front electrode substrate having a transparent electrode, and a back electrode substrate having a reflective function layer, and an uneven surface is formed on an inner surface side of the front electrode substrate. A liquid crystal display device comprising: a liquid crystal display element having a flat surface on a reflective function layer; and a projection optical system having at least one lens and one stop. When the body is in a transparent state, after the light enters the liquid crystal display element from the front electrode substrate side, the light that is regularly reflected by the reflection function layer passes through the aperture of the aperture of the projection optical system, and the liquid crystal is displayed at a desired spatial position. When the display image of the element is formed by a lens and the liquid crystal / resin composite is in a scattering state, of the light incident on the liquid crystal display element from the front electrode substrate side, the light is reflected in the vicinity of the uneven surface, and the projection optical system stops. Is 1 component for all incident light % Or less. 2. The light collecting angle of the projection optical system is δ (effective numerical aperture F =
sin ⁻¹ δ), and the inclination angle of the cross-sectional curve of the uneven surface appearing in the vertical cross section of the substrate surface of the liquid crystal display element with respect to the intersection straight line of the flat surface appearing in the cross section is defined as a position function θ (x). Assuming that the average value of θ (x) in the effective dimension length is θ _AV , the relationship θ _AV ≧ δ / 2 is satisfied, and the average value R _FR of the interfacial Fresnel reflectance between the uneven surface and the liquid crystal / resin composite.
(%) And the inclination angle component ratio Q = 1 indicating the inclination degree of the entire surface.
00 · [frequency (0 ≦ θ (x) ≦ δ / 2)] / [frequency (0
≤ θ (x) ≤ 90 °)] (%) satisfies the relationship of R _FR × Q ≤ 1%. 3. An average value R _FR (%) of interfacial Fresnel reflectance between the transparent electrode of the front electrode substrate and the liquid crystal / resin composite is 5% or less with respect to the wavelength of light incident on the liquid crystal display element. The projection type liquid crystal display device according to claim 1 or 2, wherein: 4. The light collecting angle of the projection optical system is δ (effective numerical aperture F =
sin ^-1 δ), the inclination angle of the cross-sectional curve of the uneven surface appearing in the vertical cross section of the substrate surface of the liquid crystal display element with respect to the intersection straight line of the flat surface appearing in the cross section is defined as a position function θ (x). The average value R _FR (%) of the interfacial Fresnel reflectance between the uneven surface of the electrode substrate and the liquid crystal / resin composite, and the inclination angle component ratio Q = 100 · [frequency (0 ≦ θ (x )
≦ δ / 2)] / [frequency (0 ≦ θ (x) ≦ 90 °)
4. The projection type liquid crystal display device according to claim 1, wherein Q ≦ 50% is satisfied. 5. The projection type liquid crystal display device according to claim 1, wherein the cross-sectional curve of the uneven surface appearing in the cross section perpendicular to the substrate surface has a substantially saw-tooth shape. 6. The transparent electrode is formed by transferring the saw-toothed irregularities formed in advance on the master substrate to the original substrate itself of the front electrode substrate or to a component to be attached to the original substrate, and further utilizing the transferred saw-tooth irregularities. A method for manufacturing a liquid crystal substrate for forming a substrate. 7. A liquid crystal substrate manufactured by the manufacturing method according to claim 6 is used as a front electrode substrate, an active matrix substrate is used as a back electrode substrate, and a liquid crystal / resin composite is sandwiched between the two electrode substrates. The transparent electrode of the front electrode substrate is provided with a saw-tooth uneven surface, the pitch P of the saw-tooth unevenness is smaller than the pixel size a of the back electrode substrate, and the liquid crystal / resin composite A liquid crystal display element whose average thickness G is smaller than the pixel size a.