JPH03228024A - Project liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection type liquid crystal display device using a transmission-scattering type liquid crystal display element.

[Prior Art] In recent years, a projection type liquid crystal display device using a transmission type liquid crystal display element has attracted attention as an alternative to a projection type display device using a CRT.

Conventionally, such projection-type liquid crystal display devices have mainly used a TN (twisted nematic) type liquid crystal, which has features such as low power consumption and low voltage driving.

Since this TN type liquid crystal display element requires two polarizing plates, it has the problem of low light transmittance and a dark projected image.

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

Therefore, in order to solve the problems of TN type liquid crystal display elements, we used a liquid crystal composite in which a liquid crystal material was dispersed and held in a cured matrix. Transmission-scattering type liquid crystal display elements have been proposed that utilize this transmission-scattering characteristic to take on a transmission state and a scattering state depending on whether the refractive index of the material and the cured material matrix match or differ.

In the case of a transmission-scattering type liquid crystal display element using a liquid crystal composite whose operating principle is the matching of refractive indexes, there is no need for two polarizing plates unlike a TN type liquid crystal display element, and there is no need for a projection light source. The emitted randomly polarized light can be used as direct incident light. Therefore, the transmission-scattering type liquid crystal display element can provide a transmitted image that is twice as bright as the TN type liquid crystal display element even if the same light source is used.

[Problem to be solved by the invention] A practical high-brightness light source used in a projection type liquid crystal display device is
It is not an ideal point light source but has a finite emission length, and due to factors such as aberrations in the condensing and collimating optical system, the light source optical system should be completely perpendicular to the liquid crystal display element surface (1 piece of parallel light). That was difficult.

If there is a distribution in the incident angle of the light incident on the liquid crystal display element, the scattered light component will be superimposed on the transmitted light (directly traveling light) image. For this reason, the light transmitted through the liquid crystal display element is focused by a convex lens, and an aperture with a small hole is placed near the focal point to remove unnecessary light scattered by the liquid crystal display element. Even if a light removal optical system is used, there is a problem in that the scattered light cannot be removed sufficiently, resulting in a decrease in the contrast ratio of the projected image.

Also, if you use an optical system that removes such scattered light,
As the device becomes larger, there is also a problem in that the quality of the projected image deteriorates due to aberrations caused by the lens.

Furthermore, in order to remove much of this unnecessary scattered light,
It is necessary to make the diameter of this aperture hole small. If the diameter of the aperture hole is made small, some of the originally necessary straight light that has passed through will be removed, making the projected image darker. It also had some problems.

Therefore, a projection type liquid crystal display device that uses a practical high-intensity light source, has a high contrast ratio, and can provide a bright projected image has been desired.

[Means for Solving the Problems J] The present invention has been made to solve the above-mentioned problems, and provides a projection light source, a liquid crystal display element that modulates light from the projection light source, and a liquid crystal display element that and a projection optical system that projects the transmitted light onto a projection screen, and as the liquid crystal display element, a liquid crystal substance is dispersed and held in a cured material matrix between electrode-attached substrates, and the refractive index of the cured material matrix is used. In a projection type liquid crystal display device using a liquid crystal display element sandwiching a liquid crystal composite whose index of refraction almost matches the ordinary refractive index (no) of a liquid crystal substance, at least the light incident side and the light output side of the liquid crystal display element are A projection type liquid crystal display device characterized in that an optical fiber plate is arranged in one optical path.
and a projection type liquid crystal display device characterized in that the liquid crystal display element is an active Mado Jx liquid crystal display element; A projection type liquid crystal display device characterized in that the critical angle θc of the incident angle is 4° or less, and the core fiber portion of each optical fiber of the optical fiber plate of the projection type liquid crystal display device is
The present invention provides a projection type liquid crystal display device characterized in that a cladding material portion is disposed corresponding to the ri pole portion and corresponding to a gap portion between adjacent pixel electrodes.

In the projection type liquid crystal display device of the present invention, instead of a TN type liquid crystal display element, a liquid crystal material is held in a fraction in a cured material matrix, and the refractive index (n,) of the cured material matrix is the ordinary light refraction of the liquid crystal material used. Electrically scattered depending on whether it matches or does not match the rate (no)! By using a transmissive-permanent instrument display panel sandwiching a liquid crystal composite that defines the annotation and the transmissive state, a polarizing plate is not necessary and a bright projected image can be obtained.

By arranging an optical fiber plate in the optical path on the light incidence side of this liquid crystal display element, it is possible to reduce the component that is incident obliquely among the light incident on the rear height display element.
Of the transmitted light (light that travels straight without being scattered) after passing through the liquid crystal display element, the transmitted light component that exits i↓ can be reduced, and a decrease in contrast ratio can be prevented.

In addition, by placing an optical fiber plate in the optical path on the light output side of this liquid crystal display element, part of the transmitted light (light that travels straight without being scattered) after passing through the liquid crystal display element is emitted obliquely. In addition to reducing the amount of light components, it is also possible to remove scattered light without using an optical system such as a lens or a scattered light removal optical system such as an aperture, making the device more compact and reducing the negative effects caused by aberrations caused by lenses, etc. can do.

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

Furthermore, after curing, this liquid crystal composite becomes a film with the liquid crystal substance dispersed in the cured material matrix, so there are problems such as short circuits between substrates due to pressurization of the substrates and destruction of active elements due to movement of spacers. Spots are also less likely to occur.

In addition, this liquid crystal composite has a specific resistance equivalent to that of the conventional TN mode, a small drive current, and a large accumulation like the DS (dynamic scattering) mode when using an active element for each pixel electrode. It is not necessary to provide a capacitor for each pixel electrode, which simplifies the design of the active element and allows the power consumption of the liquid crystal display element to be kept low.

Therefore, production is easy because the alignment film forming process can be removed from the manufacturing process of conventional TN mode liquid crystal display elements.

The specific resistance of the liquid crystal composite is preferably 5×10 9 Ωcm or more. Furthermore, in order to minimize the voltage drop due to leakage current etc., it is more preferable that the resistance is 1010 Ωcm or more, and in this case, it is not necessary to provide a large storage capacitance for each pixel electrode.

Since the transmission-scattering type liquid crystal display element of the present invention has inferior dynamic drive characteristics as compared to the TN type liquid crystal display element, it is preferable to provide an active element for each pixel electrode and use it as an active matrix liquid crystal display element. Examples of the active element include a transistor, a diode, a nonlinear resistance element, and the like, and two or more active elements may be arranged in one pixel as necessary. The liquid crystal composite is sandwiched between an active matrix substrate provided with such an active element and a pixel electrode connected thereto, and a counter electrode substrate provided with a counter electrode to form a liquid crystal display element.

The projection type liquid crystal display device of the present invention includes a projection light source, a transmission-scattering type liquid crystal display element using a liquid crystal composite in which a liquid crystal substance for light modulation is dispersed and held in a cured material matrix, and an image on a projection screen. The optical fiber plate is provided in an optical path on at least one of the light input side and the light output side of the projection optical system.

This optical fiber plate is a plate-like or block-like structure in which a large number of optical fibers, each consisting of a core fiber with a relatively high refractive index and a core fiber with a relatively low refractive index or covered with a rad material, are bundled two-dimensionally and bonded to each other. Any device that can transfer a planar image incident from one surface to the other surface is sufficient.

Both sides of this optical fiber plate are optically polished before use, but if necessary, one side can also be polished into a curved surface to serve as a lens-like function.

In an optical fiber such as this, in which a core fiber with a relatively large refractive index is covered with a relatively small refractive index or a rad material, light below a certain angle of incidence is totally reflected on the inner surface of the core fiber. Light that passes through the core fiber and exceeds a certain angle of incidence is not reflected by the inner surface of the core fiber, but instead leaks to the cladding material.

The numerical aperture (N
A), i.e., the maximum allowable angle of incidence of the striking power to be reversed qI! Ilf is decided. Therefore, by appropriately selecting the refractive index 〇 of the core fiber of the optical fiber and the refractive index n2 of the cladding material, the effect is that only the light below the desired incident angle θ is transmitted, and the light exceeding θ is not transmitted. is obtained.

Therefore, if the thickness of the optical fiber plate (the length of the optical fiber) is sufficient, light exceeding a desired angle of incidence can be removed. Further, it is preferable to use an optical fiber plate in which a layer for absorbing light is formed between the individual optical fibers of the optical fiber plate, since even if the plate is thin, light exceeding a desired angle of incidence can be removed.

Therefore, by arranging such an optical fiber plate in the optical path on the light incidence side of the liquid crystal display element, it is possible to prevent the incident light from the projection light source to the liquid crystal display element from being incident obliquely at an angle exceeding a certain incident angle. This allows the component to be removed, making it possible to make the incident light nearly parallel. This results in
Of the transmitted light (directly traveling light) after passing through the liquid crystal display element, the transmitted light component that is emitted obliquely can be reduced, and a decrease in contrast ratio can be prevented.

In addition, by arranging such an optical fiber plate in the optical path on the light output side of this liquid crystal display element, out of the transmitted light (straight light) that passes through the liquid crystal display element, the component that exits obliquely can be eliminated. In addition to preventing a decrease in contrast ratio, it is also possible to remove scattered light without using a scattered light removal optical system such as a lens or aperture, making it possible to miniaturize the device and reducing the adverse effects caused by aberrations caused by lenses, etc. can be reduced.

The projection light source of the present invention may consist of an ordinary light source and an optical system such as a reflecting means or lens for converting the light from the light source into parallel light beams.

Further, when the light is passed through the liquid crystal display element in RGBa colors, a dedicated light source may be used for each color, or the light from one light source may be separated and used by color separation means.

In the transmission-scattering type liquid crystal display element used in the present invention, a liquid crystal substance is dispersed and held in a cured matrix between electrode-attached substrates, and the refractive index (n,) of the cured substance matrix is the same as that of the liquid crystal substance used. This is a liquid crystal display element that sandwiches a liquid crystal composite whose refractive index almost matches the refractive index of ordinary light (fno), and transmits light when the refractive index of the cured matrix almost matches the refractive index of the liquid crystal material depending on the voltage applied state. You can use one that becomes a scattered state when they do not match.

By using an active matrix substrate in which an active element such as TPT is provided on one of the electrode-attached substrates, a high-definition liquid crystal display element can be realized.

This liquid crystal composite consists of a cured matrix with many fine pores and liquid crystal filled in the pores (liquid crystal is sealed in liquid bubbles like microcapsules). The individual microcapsules may not be completely independent, or the individual liquid crystal bubbles may be connected through slits as in a porous material. good.

The liquid crystal composite used in the liquid crystal display element of the present invention is prepared by mixing a liquid crystal substance and a material constituting a cured product matrix, and subjecting the mixture to photocuring, thermosetting, curing by solvent removal, reaction curing, etc. The cured product matrix may be separated and the liquid crystal substance may be dispersed in the cured product matrix.

Specifically, if a resin is used for the cured material matrix (,
What is necessary is just to polymerize or crosslink the resin raw materials such as mercury, oligomer, etc., to solidify the dissolved material by cooling, or to solidify by removing the solvent. Note that a material that becomes inorganic after curing may be used. However, it is preferable to use a resin for the cured material matrix because it is easy to manufacture.

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

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

Furthermore, by using a liquid crystal substance as a solvent in the liquid crystal composite and curing the photocurable resin by light exposure,
There is no need to simply evaporate solvents or water that are not needed during curing. Therefore, since it can be cured in a closed system, the conventional manufacturing method of injection into cells can be used as is, making it highly reliable.It also has the effect of bonding two substrates together with photocurable resin, making it even more reliable. becomes more sexual.

The specific manufacturing method is to form a cell using a sealing material and inject an uncured mixture of a liquid crystal material and a cured material matrix through an injection port, in the same way as a conventional normal TN type liquid crystal display element. After the entrance is sealed, it can be cured by irradiation with light or by heating.

Further, in the case of the liquid crystal display element of the present invention, without using a sealant, for example, an uncured mixture of a liquid crystal substance and a cured material matrix is supplied onto a substrate provided with a transparent electrode as a counter electrode, and then It is also possible to stack other substrates on top of each other and harden them by light irradiation or the like.

Of course, after that, a sealing material may be applied to the periphery to seal the periphery. According to this manufacturing method, simply roll-coating an uncured mixture of a liquid crystal material and a cured material matrix;
The injection process is simple and the productivity is extremely high, since it is sufficient to supply the material by spin code, printing, coating with a dispenser, etc.

In addition, the uncured mixture of these liquid crystal substances and the cured matrix may contain spacers such as ceramic particles, plastic particles, glass fibers, etc. for controlling the gap between the substrates, pigments, dyes, viscosity modifiers, and others that may affect the performance of the present invention. Additives that do not have any adverse effects may be added.

The response time of a liquid crystal display element using such a liquid crystal composite of the present invention is 3 to 50 m5 ec after the rise of voltage application.
The fall of voltage removal is about 10 to 80 m5 ec, which is faster than a conventional TN type liquid crystal display element.

In addition, its voltage-transmittance electro-optical characteristics are different from that of conventional TN.
It has a relatively gentler slope than that of a type liquid crystal display element, and it is easy to drive for gradation display. The haze value in this state is preferably 80% or more. In this liquid crystal display element, while a voltage is applied, the refractive index fn-) of the cured material matrix (after curing) is made to match the ordinary refractive index (no) of the liquid crystal material used.

As a result, when the refractive index of the cured material matrix and the refractive index of the liquid crystal material match, light is transmitted, and when they do not match, light is scattered (cloudy). The scattering properties of this element are higher than those of conventional DS mode liquid crystal display elements, and a projection display with a high contrast ratio can be obtained.

The volume fraction of operable liquid crystal material in the liquid crystal complex, Φ, is Φ
〉20% is preferable, and for higher scattering properties Φ〉
35% is preferred. On the other hand, if Φ is too thick (otherwise, the structural stability of the liquid crystal composite will deteriorate, Φ<70% is preferable. Nematic liquid crystal with positive dielectric anisotropy is used, and the refractive index (n□) of the cured material matrix is When no electric field is applied, scattering occurs due to the difference in refractive index between the unaligned liquid crystal and the cured material matrix. state (that is, a cloudy state).For this reason, when used as a projection type display device as in the present invention, light is scattered in the part without the i-pole, and there is no need to provide a light-shielding film in the part outside the pixel part kJ. Even if the light does not reach the 9 inch ring screen,
Satokumiku. By this, in order to prevent light from reaching the parts other than the pixel electrode, continuous light is applied to the parts outside the pixel electrode. It also has the advantage of eliminating the need for light shielding with a second grade, and eliminating the need for the process of forming a light shielding film.

In this case, the core fiber portions of the individual optical fibers of the original fiber plate are arranged in correspondence with each pixel electrode portion, and the cladding material portions are arranged in correspondence with each adjacent pixel electrode center portion. This reduces the amount of light in the pixel portion that is wasted and makes it easier to remove unnecessary light from each pixel r, jl 51.

2) Apply an electric field to the desired pixel in step 1. In the pixel area to which this electric field is applied, the liquid crystals are aligned, and the ordinary refractive index (no) of the liquid crystal material matches the refractive index (nm) of the cured material matrix, indicating a transparent state, and the desired pixel is Light will pass through, resulting in a bright display on the projection screen.

FIG. 1 is a schematic diagram of an example of a projection type liquid crystal display device of the present invention.

In Fig. 1, l is a projection light source, 2 is an optical fiber plate placed on the incident side, 3 is a transmission-scattering type liquid crystal display element in which a liquid crystal substance is dispersed in a cured material matrix, and 4 is on the output side. Fiber optic plate arranged,
5 is a projection optical system, and 6 is a projection screen for projecting an image.

In this example, the optical fiber plate is placed on the incident side and the output side of the liquid crystal display element, but even if it is placed only on one side, it has the effect of improving the contrast ratio of the projected image by removing light traveling diagonally. .

If the optical fiber plate is placed only on the input side, the scattered light in the output light cannot be removed without using a conventional scattered light removal optical system such as a lens or aperture. It is preferable to use an optical fiber plate on the output side because it produces the effect of removing both obliquely traveling light and scattered light.

However, it is preferable to arrange the optical fiber plates on both sides because it has a large effect of improving the contrast ratio.

In the transmission-scattering liquid crystal display element of the present invention, a liquid crystal substance is dispersed and held in a cured matrix between electrode-attached substrates, and the refractive index (n,) of the cured substance matrix is the ordinary refractive index (n,) of the liquid crystal substance used. A liquid crystal composite which is almost the same as that of (no) is sandwiched between the two.

This substrate with electrodes is In20a-SnO□(I
A substrate of glass, plastic, etc., on which a transparent electrode such as TO) or SnO□ is formed and patterned as necessary, can be prepared.

Although the electrode is usually a transparent electrode, a metal electrode such as chromium or aluminum may be used in combination to provide a low-resistance lead.

Furthermore, when the number of pixels is large, it is preferable to provide an active element in each pixel to form an active matrix liquid crystal display element. When using a three-terminal element such as a TPT (thin film transistor) as this active element, it is sufficient to provide a solid electrode common to all pixels on the counter electrode substrate.
When using a two-terminal element such as an N diode, the counter electrode substrate is patterned in a stripe shape.

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

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

On the other hand, in the present invention, as described above, the refractive index of the cured material matrix or the ordinary refractive index (no.
Since it uses a liquid crystal composite that is made to almost match the electric field, light is scattered in areas where the electric field is not applied, and the projected screen becomes black, so a light-shielding film is formed between the pixels. You don't have to. Therefore, when polycrystalline silicon is used as the active element, there is no need to form a light-shielding film on the active element part, so the process of forming the light-shielding film can be done, and the number of steps can be reduced. and improve productivity.

Such active elements are essential for high-definition display, but T
High voltage cannot be applied with PT etc. However, the transmission-scattering type liquid crystal display element used in the present invention for -M requires a relatively high voltage for driving in order to cause sufficient transmission and scattering. Therefore, in the case of driving with an active element that can only obtain a low driving voltage, the use of an optical fiber plate like the one of the present invention has a great advantage in that the contrast ratio of the projected image can be increased.

In addition to this, the projection type liquid crystal display device of the present invention may also include laminated infrared cut filters, ultraviolet cut filters, etc.
Characters, figures, etc. may be printed.

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

Specifically, photocurable acrylic resins are exemplified, and those containing acnol oligomers, which are polymerized and cured by exposure to light, are particularly preferred.

The liquid crystal material used in the present invention is a liquid crystal in which the refractive index (nl) of the cured matrix matches the ordinary refractive index (n.) of the liquid crystal material, and can be used alone or in a composition. However, in order to satisfy various performance requirements such as operating temperature range and operating voltage, it is more advantageous to use a composition.

By forming a night crystal composite in this way, there is a low risk of shorting between the upper and lower transparent electrodes, and there is no need to strictly control the orientation and substrate gap like in normal TN type display elements. Therefore, it is possible to manufacture liquid crystal display elements with extremely high productivity by controlling the transmission state and scattering state.

The projection light of the present invention (based on a conventional light source such as a halogen lamp, xenon lamp, or metal halide lamp), a reflective optical system such as a spherical reflector or a parabolic q1 plate, and a condensing optical system such as a condenser lens. A combination of projection light sources can be used.Furthermore, an infrared cut filter, an ultraviolet cut filter, a cooling means, etc. may be used in combination, if necessary.

As the projection optical system, a conventional projection optical system including lenses and the like can be used.

Furthermore, in cases where an optical fiber plate is placed only on the input side, a device to reduce the diffused light caused by scattering in the liquid crystal display element is installed on the optical path on the output side, such as an aperture or spot with a small opening at the focal point of the lens, so that the light can pass through. light(
It is also possible to increase the display contrast by removing scattered light other than straight forward light.

The projection type liquid crystal display device of the present invention may be used as a front projection type or a rear projection type.

[Function] In the projection type liquid crystal display device of the present invention, an optical fiber plate is disposed in the optical path on at least one of the light incident side and the light output side of a transmission-scattering type liquid crystal display element using a liquid crystal composite.

The optical fiber used in this optical fiber plate, in which a core fiber with a relatively high refractive index is covered with a rad material with a relatively low refractive index, completely reflects light below a certain angle of incidence on the inner surface of the core fiber. light passes through,
Light exceeding a certain angle of incidence is not reflected by the inner surface of the core fiber and leaks to the cladding material side.

The relationship between the incident angle θ of the transmitted light and the optical fiber plate when using an optical fiber in which the core fiber has a refractive index of n3 and the cladding material has a refractive index of n2 will be described with reference to FIG.

In FIG. 2, light +1 has an incident angle θ. and the refractive index n. enters the optical fiber plate 12 from a medium such as the atmosphere,
It is refracted at the core fiber interface at a refraction angle θ, and enters the interface with the crat material at an incident angle of 90° θ1.

, @+03 or more enters the cladding material as refracted light 13, and light less than that undergoes total internal reflection and is reflected into the core fiber as light 14.

Also, according to the 5nell's law, the relationship between θ0 and θ is no sin θ. = old sin θ1, so the light 14 propagating in the core fiber has an incident angle θ on the optical fiber plate. Light at an incident angle that satisfies equation (1) enters the cladding material without being totally reflected, and is absorbed by the light-absorbing layer between each optical fiber and disappears.
Do not touch the other end of the optical fiber plate.

(From equation 11, the critical angle θc can be changed by changing the values of n3 and n2. In the present invention, the critical angle θc is 10
It can be used if it is below °. However, in the present invention, it is preferable that only light from the perpendicular direction is transmitted as much as possible, so it is better to transmit a certain amount of light from an oblique direction, as is the case with conventional optical fiber plates.
It is preferable that this critical angle is small, and specifically, it is preferable to set it to 4° or less because it is efficient in removing light incident from an oblique direction. In particular, it is preferable that the angle is 2° or less.

Another feature of the optical fiber plate is that it transfers the image on the light input side of the optical fiber plate to the light output side at a resolution that corresponds to the aperture of the core fiber. It is known to act as a plate. This means that
It is also possible to use a collimated hole made by bundling hollow metal small-diameter vibrators, which has been known as a method of obtaining parallel light, but unlike an optical fiber plate, it is based on total internal reflection (the Since this is not a light propagation phenomenon, the amount of soil used is low and it does not function as a face plate with zero thickness, so it is not suitable for the projection type liquid crystal display device of the present invention.

[Example 1] In a projection type liquid crystal display device as shown in Fig. 1, a 150W metal halide lamp and a parabolic reflector are used as the projection light source 1, and an optical fiber plate 2 on the input side and an optical fiber plate 2 on the output side are used. An optical fiber plate 4 is provided with a TPT liquid crystal composite in which a liquid crystal substance is dispersed and held in a resin matrix on each pixel electrode.
A projection optical system 5 consisting of a lens is used, which is glued to both sides of a transmission-scattering active matrix type liquid crystal display element 3 sandwiched between an active matrix glass substrate provided with an ITO glass substrate and a glass substrate with ITO. was used to project onto the projection screen 6.

This optical fiber plate has a thickness of 2mm, a core fiber diameter of 12μm, a lead glass with a refractive index of 1.8, and a thickness of 1~
The material used was made of a light-absorbing cladding material with a thickness of 2 μm, and had a critical angle θc of the incident angle of light to the optical fiber plate for total reflection in the optical fiber of approximately 2″′.

The liquid crystal display element contains 6 parts of 2-ethylhexyl acrylate, 18 parts of hydroxyethyl acrylate, 20 parts of acrylic oligomer, 0.4 part of photocuring initiator, and BDH.
A solution prepared by mixing and dissolving 62 parts of liquid crystal rE-8J manufactured by Co., Ltd. was injected into an empty cell consisting of an active matrix glass substrate with TPT on each pixel electrode and a glass substrate with ITO, and irradiated with ultraviolet rays for 60 seconds. .

The gap between the substrates was 11 μm, the average diameter of the liquid crystal components in the resin 71 to liquid was 19 μm, the refractive index anisotropy Δn of the liquid crystal material was about 024, and the dielectric anisotropy Δε was about 15.6.

As a result, a high contrast ratio of 50 or more on the screen was obtained.

Example 2 Light from a light source is separated into three colors of RGB by a dichroic mirror, and then irradiated to three liquid crystal display elements using the product composite, and the transmitted light from the three liquid crystal display elements is The images were synthesized using a dichroic mirror and projected onto a projection screen using a projection optical system.

In this example, the optical fiber plate is placed between the projection light source and the first dichroic mirror on the input side,
On the output side, three panels were placed in close contact with the output side of each liquid crystal display element. The optical fiber plate disposed in close contact with the light output side was an optical fiber plate whose light output side (the side opposite to the liquid crystal display element) was processed into a convex lens shape. In addition, the core fiber diameter of these optical fiber bullets is 10 μm, the lead glass has a refractive index of 176, and the thickness is approximately ILL.
The optical fiber plate was made of a light-absorbing cladding material with a critical angle θc of about 1.5° for the incident angle of light to the optical fiber plate for total reflection of the light in the optical fiber.

As a result, the contrast ratio on the screen is 480n
m blue light is about 120, 520 nm green light is about 100
, a high value of about 80 was obtained with red light of 620 nm. Note that the contrast ratio differs depending on the color because the contrast ratio of each liquid crystal display element differs depending on the wavelength.

Note that the substrate/gap d of the liquid crystal display element and/or the average diameter R of the liquid crystal dispersion in the resin matrix are changed for each color, and dR
>dc>da, RR>Ra>Ra are preferred. In addition, the critical angle θ due to the color of the optical fiber plate
c may be set to OCR<θco<θcB.

In addition, +68 for red, green, and blue are shown, respectively.

Example 3 The pitch between the core fiber and cladding material of each optical fiber of the optical fiber plate was made to be the same as the pixel pitch of the active matrix substrate, so that the core fiber portion almost corresponded to each pixel electrode portion, and the cladding material portion It is arranged so as to substantially correspond to the gap between adjacent pixel electrodes.

As a result, light from the pixel area effectively enters the core fiber and is less likely to be lost in the cladding material area, resulting in improved brightness.

In particular, when applied to an optical fiber plate placed on the input side, light does not emit to parts that require light shielding, such as the TPT part, so it is possible to omit or simplify the TPT's light shielding. Ji.

Example 4 The projection type liquid crystal display device of Example 1 was the same as Example 1 except that an optical fiber plate was provided only on the incident side of the liquid crystal display element, and a means for removing scattered light using a condenser lens and an aperture was added to the projection optical system. I did the same thing.

This projection type liquid crystal display device had a higher contrast ratio of a projected image than a projection type liquid crystal display device not provided with an optical fiber plate on the incident side.

However, without adding the scattered light removal means, the contrast ratio of the projected image was significantly reduced.

Example 5 The projection type liquid crystal display device of Example 1 was the same as Example 1 except that the optical fiber plate was provided only on the output side of the liquid crystal display element.

Although the contrast ratio of the projected image of this projection type liquid crystal display device was high, the contrast ratio of the projected image was lower than that of a projection type liquid crystal display device without optical fiber plates provided on both sides.

However, there is no need to add a means for removing scattered light, and there is also the advantage of miniaturization of the device.

[Effects of the Invention] In the projection type liquid crystal display device of the present invention, a liquid crystal display element in which a liquid crystal composite whose scattering state and transmission state are electrically controlled is sandwiched as a liquid crystal material sandwiched between substrates with electrodes is used. Because of this, there is no need for a polarizing plate, and the transmittance of light during transmission can be greatly improved, resulting in a bright projected image.

In the present invention, by arranging an optical fiber plate in the optical path on the light incidence side of the liquid crystal display element, out of the incident light from the light source for projection to the liquid crystal display element, oblique light that is not completely parallel is incident. Among the transmitted light (straight light) after passing through the liquid crystal display element,
It is possible to reduce the transmitted light component that is emitted obliquely, and it is possible to prevent a decrease in the contrast ratio of the projected image.

In addition, by placing an optical fiber plate in the optical path on the light output side of this liquid crystal display element, it is possible to reduce the components of the transmitted light (straight light) that are emitted obliquely after passing through the liquid crystal display element. , scattered light can be removed without using an optical system such as a lens or a scattered light removal optical system such as an aperture, and the device can be made smaller.
It is possible to reduce the negative effects caused by aberrations caused by lenses, etc.

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

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a basic example of a projection type liquid crystal display device of the present invention. FIG. 2 is a partially enlarged explanatory diagram for explaining the critical angle of the optical fiber plate. Projection light source: 1 Optical fiber plate = 2, 4 transmission-scattering type liquid crystal display element: 3 Projection optical system: 5 Projection screen: 6

Claims (4)

[Claims] (1) It has a projection light source, a liquid crystal display element that modulates the light from the projection light source, and a projection optical system that projects the light transmitted through the liquid crystal display element onto a projection screen, and as the liquid crystal display element. A liquid crystal composite in which a liquid crystal material is dispersed and held in a cured material matrix and the refractive index of the cured material matrix is made to almost match the ordinary refractive index (n_o) of the liquid crystal material used is sandwiched between the electrode-attached substrates. 1. A projection type liquid crystal display device using a liquid crystal display element, characterized in that an optical fiber plate is disposed in an optical path on at least one of a light input side and a light output side of the liquid crystal display element. (2) The projection type liquid crystal display device according to claim 1, wherein the liquid crystal display element is an active matrix liquid crystal display element. (3) The projection type liquid crystal display device according to claim 2, wherein the critical angle θc of the incident angle of light to the optical fiber plate for total reflection of the light in the optical fibers of the optical fiber plate is 4° or less. (4) In any one of claims 1 to 3, the core fiber portion of each optical fiber of the optical fiber plate corresponds to each pixel electrode portion, and the cladding material portion is arranged corresponding to each adjacent pixel electrode gap portion. A projection type liquid crystal display device characterized by: