JP2803214B2 - Liquid crystal resin composite, active matrix liquid crystal display element, and projection type active matrix liquid crystal display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an active matrix liquid crystal display device and a projection type active matrix liquid crystal display device.

[Prior Art] In recent years, liquid crystal displays have been utilizing personal word processors,
Widely used in handheld computers, pocket TVs, etc. Among them, an active matrix liquid crystal display element in which an active element is arranged for each pixel electrode has attracted attention and is being actively developed.

Initially, such liquid crystal display devices were DSM (dynamic scattering)
A liquid crystal display device using a liquid crystal of the liquid crystal type has been proposed.
The M type has a drawback that the current flowing through the liquid crystal is high, so that the current consumption is large. Currently, TN (twisted nematic) type liquid crystal is mainly used, and it appears on the market as a pocket TV. The TN type liquid crystal has a very small leakage current and low power consumption, and thus is suitable for a battery-powered application.

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

In the TN mode, since the leakage current of the liquid crystal itself is extremely small, it is not necessary to add a large storage capacity, and the power consumption of the liquid crystal display element itself can be reduced.

However, since the TN mode requires two polarizing plates, there is a problem that light transmittance is small.

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

In order to solve the problem of the TN mode, a mode using a scattering-transmission characteristic of a liquid crystal resin composite in which a nematic liquid crystal is dispersed and held in a resin matrix has been proposed.

However, there were problems that a sufficient luminance and contrast ratio could not be obtained at a low voltage, and that it was difficult to achieve color balance.

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and has a plurality of color light sources, a plurality of active matrix liquid crystal display elements to which light from each color light source is incident, and In a projection type active matrix liquid crystal display device having a projection optical system for synthesizing and projecting light emitted from the active matrix liquid crystal display element, the active matrix liquid crystal display element faces an active matrix substrate provided with an active element for each pixel electrode. A liquid crystal resin composite in which nematic liquid crystal with positive dielectric anisotropy is dispersed and held in a resin matrix is sandwiched between a counter electrode substrate provided with electrodes, and the refractive index of the resin matrix uses the ordinary light of the liquid crystal. The refractive index (n _o ) is made to substantially coincide with the refractive index (n _o ).
0.18 or more, the average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, and the electrode gap d _X (μm) for each color.
m), 0.3 <R · Δn <0.7 (1) for the gap d _G (μm) between the two electrodes when the main wavelength λ _X of the color of each light source is the main wavelength λ _G = 540 nm of the green light source. 4 R <d _G <8R (2) And a projection type active matrix liquid crystal display device characterized by satisfying the following relationship: the projection type active matrix liquid crystal display device is provided with a light source of three colors RGB and three active matrix liquid crystal display elements, The two electrode gaps d _R , d _G , and d _{B of} the liquid crystal display element, and the main wavelengths λ _R , λ _G , and λ _B of the colors of each light source are The projection type active matrix liquid crystal display device characterized by satisfying the relationship, and the resin used for the liquid crystal resin composite of the active matrix liquid crystal display element is a photocurable vinyl resin, the liquid crystal and the liquid crystal A projection type active matrix liquid crystal display device characterized by using a liquid crystal resin composite obtained by irradiating a solution in which a resin is uniformly dissolved with light and curing the resin, and
In an active matrix liquid crystal display device having a plurality of color filters, a nematic liquid crystal having a positive dielectric anisotropy is provided between an active matrix substrate provided with an active element for each pixel electrode and a counter electrode substrate provided with a counter electrode. Sandwiches a liquid crystal resin composite dispersed and held in a resin matrix, so that the refractive index of the resin matrix substantially matches the ordinary refractive index (n _o ) of the liquid crystal used. The anisotropy Δn is 0.18 or more, and the average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, the gap d _X (μm) between both electrodes of each color, and the main wavelength λ _X of the transmitted light of each color filter are 0.3 <R · Δn <0.7 (1) 4 R <d _G <8R (2) for the gap d _G (μm) between the two electrodes when the main wavelength λ _G = 540 nm of the green light source. An active matrix liquid crystal display element characterized by satisfying the following relationship; and the active matrix liquid crystal display element has a color filter of three colors of RGB, and both electrodes of the liquid crystal display element corresponding to the three color filter portions. The gaps d _R , d _G , and d _B , and the main wavelengths λ _R , λ _G , and λ _B of the transmitted light of each color filter are Active matrix liquid crystal display element characterized by satisfying the relationship, and the resin used in the liquid crystal resin composite of those active matrix liquid crystal display element is a photo-curable vinyl resin, the liquid crystal and the resin Matrix liquid crystal display element characterized by using a liquid crystal resin composite obtained by irradiating a solution in which is uniformly dissolved with light and curing the resin, the active matrix liquid crystal display element, the light source for projection and the projection A projection type active matrix liquid crystal display device having an optical system, an active matrix substrate provided with an active element for each pixel electrode,
A liquid crystal resin composite in which nematic liquid crystal having positive dielectric anisotropy is dispersed and held in a resin matrix is sandwiched between a counter electrode substrate provided with a counter electrode, and the refractive index of the resin matrix is used for the liquid crystal used. ordinary is refractive index (n _o) in roughly matches the refractive index anisotropy Δn of the liquid crystal used is not less 0.18 or more, the resin matrix is 2-ethylhexyl acrylate, hydroxyethyl acrylate, acrylic oligomer, photo-curing initiator An active matrix liquid crystal display element characterized by being formed by curing a melt containing
A liquid crystal resin composite in which nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a resin matrix, and is sandwiched between a pair of substrates with electrodes. ordinary is refractive index (n _o) in roughly matches the refractive index anisotropy Δn of the liquid crystal used is not less 0.18 or more, and the average of the liquid crystal is dispersed and held in a resin matrix particle diameter R ([mu] m), The gap d _X (μm) between the two electrodes and the main wavelength λ _X of the color of the light source are equal to the main wavelength λ _G = 540n of the green light source.
For both electrode gap d _G (μm) in the case of a m, 0.3 <R · Δn < 0.7 (1) 4 R <d G <8 R (2) Is to provide a liquid crystal resin composite satisfying the following relationship.

In the active matrix liquid crystal display element and the projection type active matrix liquid crystal display device of the present invention, the liquid crystal material sandwiched between the active matrix substrate and the counter electrode substrate is a liquid crystal capable of electrically controlling a scattering state and a transmission state. Since an active matrix liquid crystal display element sandwiching a resin composite is used, a polarizing plate is not required, and light transmittance at the time of transmission can be greatly improved. Furthermore, since the average particle diameter R (μm) in the liquid crystal resin composite is optimized to be constant and the electrode gap d _X (μm) is optimized and set for each color, colors are mixed in display, especially in projection display. At this time, a display with good color balance, brightness, and good contrast ratio can be obtained.

In addition, since problems such as alignment treatment indispensable for the TN type liquid crystal display element and destruction of the active element due to generated static electricity can be avoided, the production yield of the active matrix liquid crystal display element can be greatly improved.

Further, since the liquid crystal resin composite is in the form of a film after curing, problems such as short-circuiting between substrates due to pressurization of the substrates and destruction of the active element due to movement of the spacer hardly occur.

In addition, this liquid crystal resin composite has the same specific resistance as that of the conventional TN mode, and does not require a large storage capacitor for each pixel electrode as in the DS mode. In addition, the power consumption of the liquid crystal display element can be kept low. Therefore, since the production can be performed by simply removing the alignment film forming step from the conventional TN mode liquid crystal display element production process, the production is easy.

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

Examples of the active element provided on the pixel electrode include a transistor, a diode, and a non-linear resistance element. Two or more active elements may be arranged in one pixel as needed. A liquid crystal display element is obtained by sandwiching the liquid crystal resin composite 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. When a color filter is used, a plurality of color filters are formed on one of the substrates.

A projection type active matrix liquid crystal display device using a liquid crystal display element for each color according to the present invention uses a plurality of color light sources and a projection optical system. As a projection type active matrix liquid crystal display device using a liquid crystal display element using a plurality of color filters, one light source for projection and one projection optical system are used. As the color light source, the projection light source, and the projection optical system, a conventionally known projection optical system such as a projection light source and a lens can be used.

As this color light source, a dedicated light source may be used for each color, or the light of one light source may be used by splitting. The light emitted from this color light source is made incident on an active matrix liquid crystal display device. In the present invention, the plurality of active matrix liquid crystal display elements are used in accordance with the characteristics of each light source color. Light emitted from these active matrix liquid crystal display elements is mixed and projected. As a result, a bright, well-balanced and high-contrast projected image can be obtained.

Also, in the case of a projection type active matrix liquid crystal display device using a liquid crystal display element using a color filter, usually, a single active matrix liquid crystal display device in which a substrate gap is adjusted in a color filter portion for each color from a white light source. Light enters the element and is projected by one projection optical system. As a result, a bright and well-balanced color image can be obtained without a troublesome adjustment such as adjustment of the optical axis of the projection optical system, and a projection image with a high contrast ratio can be obtained.

In the present invention, the liquid crystal resin composite is composed of a resin matrix in which a large number of fine holes are formed and a nematic liquid crystal having a positive dielectric anisotropy filled in the holes, and the refractive index of the resin matrix is used. A liquid crystal resin composite that is made to substantially match the ordinary refractive index (n _o ) of the liquid crystal and has a liquid crystal refractive index anisotropy Δn of 0.18 or more is used. This liquid crystal resin composite is sandwiched between an active matrix substrate and a counter electrode substrate to form a liquid crystal display element. Depending on the state of voltage application between the electrodes of the liquid crystal display element, the refractive index of the liquid crystal changes, and the relationship between the refractive index of the resin matrix and the refractive index of the liquid crystal changes. State, and when the refractive index is different, the state is a scattering state. In the present invention, the liquid crystal display element specifically refers to an active matrix liquid crystal display element. However, as long as a liquid crystal resin composite that transmits and scatters light is used, the configuration of the active matrix liquid crystal display element is used. Without being limited thereto, its good optical performance can be used.

The liquid crystal resin composite composed of the resin matrix in which a large number of fine holes are formed and the liquid crystal filled in the holes has a structure in which the liquid crystal is sealed in a liquid bubble such as a microcapsule. The individual microcapsules do not have to be completely independent, and liquid bubbles of individual liquid crystals may be communicated via the slits like a porous body.

The liquid crystal resin composite used in the liquid crystal display element of the present invention is prepared by mixing nematic liquid crystal and a material constituting a resin matrix into a solution or a latex, and curing the mixture by photocuring, heat curing, and solvent removal. The resin matrix may be separated by curing, reaction curing, or the like, so that the nematic liquid crystal is dispersed in the resin matrix.

It is preferable to use a photo-curing or heat-curing resin, because the resin can be cured in a closed system.

In particular, the use of a photo-curing type resin is preferable because it can be cured in a short time without being affected by heat.

As a specific manufacturing method, a cell is formed using a sealing material in the same manner as a conventional ordinary nematic liquid crystal, a mixture of an uncured nematic liquid crystal and a resin matrix is injected from an injection port, and the injection port is sealed. After that, it can be cured by irradiating light or heating.

In the case of the liquid crystal display element of the present invention, without using a sealing material, for example, a mixture of an uncured nematic liquid crystal and a resin matrix is supplied on a substrate provided with a transparent electrode as a counter electrode, and thereafter, An active matrix substrate provided with an active element for each pixel electrode may be stacked and cured 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, the mixture of the uncured nematic liquid crystal and the resin matrix may be simply supplied by roll coating, spin coating, printing, coating with a dispenser, or the like, so that the injection step is simple and the productivity is extremely high. Good.

In addition, the mixture of the uncured nematic liquid crystal and the resin matrix may have 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.

By curing this element in a state where a sufficiently high voltage is applied only to a specific part at the time of this curing step, that part can always be in a light transmitting state, so if there is something to be fixedly displayed, May form such a normally transparent portion.

The response time of such a liquid crystal display device using the liquid crystal resin composite of the present invention is such that the rise of the voltage application is 3 to 50 msec.
The voltage drop is about 10 to 80 msec, which is faster than the conventional TN mode liquid crystal display device.

Further, the electro-optical characteristics of the voltage-transmittance are the same as those of the conventional TN
Compared to the liquid crystal display element in the mode, the mode is relatively gentle, and driving for gradation display is easy.

The transmittance of the liquid crystal display device using the liquid crystal resin composite in the transmission state is preferably as high as possible, and the haze value in the scattering state is preferably 80% or more.

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

Accordingly, light is transmitted when the refractive index of the resin matrix and the refractive index of the liquid crystal match, and the light is scattered (white turbid) when they do not match. The scattering properties of this element
A display having a higher contrast ratio and higher than that of the liquid crystal display element of the DS mode can be obtained.

An object of the present invention is to provide an optimal configuration of a projection type active matrix liquid crystal display device using an active matrix liquid crystal display element sandwiching the liquid crystal resin composite.

That is, an object of the present invention is to provide a projection type active matrix liquid crystal display device which has a high transmittance at the time of transmission and a high scattering property (light shielding property) at the time of scattering, has a good color balance, and has a large contrast ratio.

The factors for determining the electro-optical characteristic of the active matrix liquid crystal display device using the liquid crystal polymer composite material, the refractive index of the liquid crystal used (ordinary refractive index n _o, the extraordinary refractive index n _e),
Relative permittivity (ε, ⊥, and ⊥ indicate parallel and perpendicular to the liquid crystal molecular axis, respectively), viscosity, elastic constant, refractive index n _p , relative permittivity ε _p , elastic modulus, and resin matrix of the resin used. The average particle diameter R of the liquid crystal dispersed and held therein, the volume fraction Φ, the gap between both electrode substrates (thickness of the liquid crystal resin composite) d, the maximum effective applied voltage applied to the liquid crystal resin composite in the pixel portion by the active element V and the like. Here, the liquid crystal average particle diameter R indicates a diameter of the liquid crystal when the liquid crystal forms a substantially spherical liquid bubble, and a region where the directors of the liquid crystal have a correlation with each other when the liquid crystal has a porous communication structure. Means the diameter of

The electro-optical characteristics of the active matrix liquid crystal display device using the liquid crystal resin composite of the present invention include a high scattering property in the absence of an electric field, and a high transmittance in the application of an electric field, that is, a high display contrast ratio. It is desirable to have. When projection display is performed using such a liquid crystal display element, a display with high luminance and a high contrast ratio can be obtained.

In order to obtain such a display, it is necessary that the above factors have an optimal relationship.

Particularly important factor that determines the electro-optical characteristic of the active matrix liquid crystal display element among these factors are the refractive index of the liquid crystal used (refractive index anisotropy [Delta] n = extraordinary refractive index n _e -
It is the ordinary light refractive index n _o ), the average particle diameter R of the liquid crystal, and the gap d between both electrode substrates. The gap d _X between both electrode substrates is optimized for each liquid crystal display element according to the main wavelength λ _X of the color light source. I do.

In the present invention, since the average particle diameter R of the liquid crystal is not changed depending on the color, the production is easy, and a plurality of colors can be displayed by using a color filter in one liquid crystal display element.

Liquid crystal refractive index anisotropy Δn of using (= n _e -n _o) contributes to scattering at the time of no electric field, to obtain a high scattering property, preferably more than a certain large, specifically Δ
n ≧ 0.18 is a preferable condition. Further, the ordinary refractive index n _o of the liquid crystal used is preferably substantially matches the refractive index n _p of the resin matrix, high transparency is obtained during this time an electric field is applied. Specifically, it is preferable to satisfy the relationship of _{n o -0.03 <n p <n} o +0.05.

The average particle size R of the liquid crystal dispersed and held in the resin matrix is a very important factor, and contributes to the scattering property in the absence of an electric field and the operation characteristics of the liquid crystal in the presence of an electric field. The scattering property in the absence of an electric field varies depending on the relationship between the refractive index anisotropy Δn of the liquid crystal used, the wavelength λ of light, and the average particle diameter R of the liquid crystal. Therefore, depending on the dominant wavelength lambda _X of each light source, for maximum scattering per unit operation amount of the liquid crystal, the average particle diameter R of liquid crystal, the two electrode substrates gap d _X below for each liquid crystal display element It is necessary to set as follows.

When the main wavelength of the green light source is λ _G = 540 nm, the average particle diameter of the liquid crystal is R (μm), and the gap between the electrode substrates is d _G.

0.3 <R · Δn <0.7 (1) 4 R <d _G <8R (2) In particular, since the color of the light source is green, 0.4 <R · Δn <0.6
It is preferable that when Δn = 0.25, R is 2.
It becomes about 0 μm. Further, it is preferable that Δn is 0.2 or more in order to obtain strong scattering.

When the average particle diameter R of the liquid crystal display element with respect to the green light source is smaller than the range of the expression (1), the scattering property has a wavelength dependency that the shorter wavelength side is stronger, and the operation of the liquid crystal is increased. Since a high electric field is required, there is also a problem that power consumption increases. On the other hand, when the average particle diameter R is larger than the range of the formula (1), the wavelength dependence of the scattering property is small, but the scattering property is weak over the entire visible light range, the contrast ratio is reduced, and the scattering from the time of transmission is started. There is also a problem that the response to the sexual response is slow. Therefore, the above range is set.

The electrode substrate gap d _G of the liquid crystal display element for a green light source is also an important factor. When d _G is increased, the scattering property in the absence of an electric field is improved. However, if d _G is too large, and requires a high voltage in order to achieve sufficient transparency when an electric field is applied, increase in the power consumption, the active element for a conventional TN, drive
The problem that an IC cannot be used arises. D _G
When is small, high transparency can be obtained at a low voltage, but the scattering in the absence of an electric field decreases. For this reason, in order to achieve both scattering when no electric field is applied and high transparency when applying an electric field,
d _G (μm) is set so as to satisfy the above equation (2).

In the present invention, even in the case of displaying a plurality of colors, the average particle diameter R of the liquid crystal does not need to be changed depending on the color, so that the production is easy. While color display is possible, dominant wavelength λ _X
And the relationship between the two electrode gap d _X is allowable width is narrowed.

For this reason, in order to make the characteristics for each color uniform, all the liquid crystal display elements or their color filter parts must be And almost as follows.

The expression (3) is for optimizing the scattering property of the liquid crystal and for matching the voltage-transmittance characteristics of each color.

Therefore, by simultaneously satisfying these conditions, it is possible to obtain a display device having a high luminance, a high contrast ratio and a good color balance with a uniform voltage-transmittance characteristic, in particular, a projection type liquid crystal display device.

In particular, each of a plurality of liquid crystal display elements or a liquid crystal display element with a color filter It is optimal to match with.

For this reason, when three color light sources or color filters of RGB (red, green, blue) are used, d _X and λ _{X of} three liquid crystal display elements or a liquid crystal display element with a color filter are used.
Align almost with the relationship. Specifically, the following is performed.

The absolute value of the electrode substrates gap d _X, depending on the applied voltage to be used, the display brightness may be selected so that the contrast ratio is optimal. If a rectangular wave at 0-V _MAX is applied, the effective applied voltage is the same as the applied voltage.
It is preferable to set the following range.

0.5R · V _MAX <d _G <R · V _MAX (5) In particular, it is preferable to be 0.8R · V _MAX or less. TFT like a normal TN type active matrix liquid crystal display
In the case where is used, the effective applied voltage is preferably set to 10 V or less. For example, when V _MAX = 8 V, d _G is approximately 8 to
It may be about 13 μm.

For example, when d _G = 10 μm, d _R ≒ 11 μm and d _B ≒
By setting the thickness to 9 μm, it is possible to obtain a color-balanced display while keeping the average particle diameter R of the liquid crystal constant.

In the case of a liquid crystal display element for each of the three colors, a liquid crystal display element in which the gap between the two electrodes is set as described above may be manufactured for each color, and in the case of a liquid crystal display element using a color filter, The gap between both electrodes of the pixel may be changed as described above for each color of the color filter.

As a result, even if the driving voltage or the like is not adjusted for each color on the driving circuit side, it is possible to obtain a display with a uniform characteristic of each color, that is, a color balance and a high contrast ratio.

The liquid crystal used must have a refractive index anisotropy Δn of 0.18 or more. Above all, it is preferably at least 0.20, particularly preferably at least 0.23. The relative dielectric anisotropy Δε (= ε ＝ −ε) is preferably 10 or more, and particularly preferably 13 or more.

The color balance by a plurality of liquid crystal display elements can be improved to some extent by modulating the drive signal, but when there is no electric field, the balance of the characteristics on the low voltage side by gradation display is
It is difficult to improve only by modulating the drive signal.

One major advantage of the present invention is that the voltage-transmittance characteristics for each color are aligned without strongly depending on the modulation of the drive signal.
That is, a display with a well-balanced color can be obtained.

As described above, using a plurality of active matrix liquid crystal display elements using a liquid crystal resin composite which is in a transparent state when a voltage is applied and in a scattering state when no electric field is applied, each liquid crystal display element corresponding to each color light source is represented by the above formula. (1), (2),
By satisfying all of the conditions (3) and (4), a bright display having a good color balance and a high contrast ratio can be achieved by using the conventional active elements and driving ICs for TN. . More specifically, a display with a contrast ratio of several tens or more and a transmittance when an electric field is applied of 70% or more is also possible. Further, since the dynamic range is wide, an excellent element capable of displaying fine halftones can be obtained.

Further, in order to improve the scattering property in the absence of an electric field, it is effective to increase the volume fraction Φ of the operable liquid crystal in the liquid crystal resin composite, and Φ> 20% is preferable. To have Φ> 35% is preferred. On the other hand, if Φ is too large, the structural stability of the liquid crystal resin composite deteriorates, so Φ <70% is preferable.

When no electric field is applied, the liquid crystal display element of the present invention shows a scattering state (that is, a cloudy state) due to a difference in refractive index between the liquid crystal that is not aligned and the resin matrix. For this reason, when used as a projection display device as in the present invention, light is scattered in portions without electrodes, and light does not reach the screen without providing a light-shielding film in portions other than the pixel portion, Looks black. This eliminates the need to shield portions other than the pixel electrodes with a light shielding film or the like in order to prevent light leakage from portions other than the pixel electrodes.
Another advantage is that the step of forming the light-shielding film is not required.

Then, an electric field is applied to a desired pixel. In the pixel portion to which the electric field is applied, the liquid crystal is aligned, and the ordinary light refractive index (n _o ) of the liquid crystal matches the refractive index (n _p ) of the resin matrix to indicate a transmissive state. Light is transmitted, and the image is displayed brightly on the screen.

By curing this element in a state where a sufficiently high voltage is applied only to a specific portion during the curing step,
Since the portion can always be in a light transmitting state, if there is something to be fixedly displayed, such a normally transmitting portion may be formed.

Further, a dye, a pigment, and the like may be mixed in the liquid crystal resin composite.

FIG. 1 is a schematic diagram of an example using a dichroic prism of a projection type active matrix liquid crystal display device of the present invention.

In FIG. 1, 1 is a light source, 2 is a concave mirror, 3 is a condenser lens, 4 is a dichroic prism for spectrum, 5
A, 5B, 5C, and 5D are mirrors, and constitute a color light source with 1 to 5D. 6A, 6B, 6C are active matrix liquid crystal display elements sandwiching a liquid crystal resin composite corresponding to each color, 7 is a dichroic prism for synthesis, 8 is a projection lens, 9 is an aperture for removing light other than straight light, and 10 is projection Screen. 7 to 9 constitute a projection optical system.

FIG. 2 is a schematic view of an example of the projection type active matrix liquid crystal display device of the present invention in which a dichroic prism is not used.

In FIG. 2, 11 is a light source, 12 is a concave mirror, 13 is a condenser lens, 15A, 15B and 15C are dichroic mirrors, and 11 to 15C constitute a color light source. 16A, 16B, 16C are active matrix liquid crystal display elements sandwiching a liquid crystal resin composite corresponding to each color, 18A, 18B, 18C are projection lenses provided for each color, 19A, 19B, 19C are provided for each color An aperture for removing light other than straight light, 20 is a projection screen. The projection optical system is composed of 18A to 19C.

FIG. 3 is a sectional view of an active matrix liquid crystal display element used in the projection type active matrix liquid crystal display device of the present invention, and shows an example in which the liquid crystal display element is changed for each color.

In FIG. 3, reference numeral 21 denotes an active matrix liquid crystal display element; 22, a substrate made of glass or plastic for an active matrix substrate; 23, a pixel electrode such as ITO (In ₂ O ₃ —SnO ₂ ) and SnO _2; , A diode, a non-linear resistance element, etc., 25 is a glass or plastic substrate for a counter electrode substrate, 26 is a counter electrode such as ITO or SnO ₂ and 27 is a liquid crystal resin composite sandwiched between both substrates. Is shown.

FIG. 4 is a sectional view of an example in which a color filter is provided.

In FIG. 4, 31 is an active matrix liquid crystal display element, 32 is a substrate for an active matrix substrate, 33 is a pixel electrode, 34 is an active element, 35 is a substrate of a counter electrode substrate, 36 is a counter electrode, and 37 is a liquid crystal resin composite. Body, 38 is the counter electrode 36 and the substrate
35 shows a color filter arranged between the color filter 35 and the color filter.
The electrode gap is changed for each pixel by the main wavelength of the color filter.

When a three-terminal element such as a TFT (thin film transistor) is used as the active element of the present invention, the counter electrode substrate may be provided with a solid electrode common to all pixels, but when a two-terminal element such as a MIM element or a PIN diode is used. In this method, the counter electrode substrate is patterned in a stripe shape.

When a TFT is used as an active element, silicon is suitable as a semiconductor material. In particular, polycrystalline silicon is not as photosensitive as amorphous silicon,
Even if the light from the light source is not blocked by the light-blocking film, no malfunction occurs, which is preferable. 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.

When amorphous silicon is used as a semiconductor material, a light-shielding film is formed in a TFT portion, so that the semiconductor device can be used for a projection-type liquid crystal display device.

In the case of a conventional TN-type liquid crystal display device, a light-shielding film is often formed between pixels in order to suppress light leakage from between the pixels. The formation of the light-shielding film in the active element portion does not significantly affect the entire process. That is, even if polycrystalline silicon is used as an active element and a light-shielding film is not formed in an active element portion, the number of steps cannot be reduced if a light-shielding film needs to be formed between pixels.

In contrast, in the present invention, as described above, due to the use of liquid crystal ordinary refractive index (n _o) and liquid crystal polymer composite material which is adapted substantially to match that used by the refractive index of the resin matrix, an electric field Since light is scattered and blackened on a projected screen in a portion where is not applied, a light-shielding film need not be formed between pixels. For this reason, when polycrystalline silicon is used as the active element, a light-shielding film need not be formed in the active element part, so that the step of forming the light-shielding film can be eliminated, and the number of steps can be reduced, and productivity can be reduced. Is improved.

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

When the active matrix liquid crystal display element of the present invention is used in a reflection type, compared to the case of using a transmission type,
A high contrast ratio can be obtained in the same electrode substrate gap. Therefore, when it is sufficient to obtain the same contrast ratio as that of the transmission type, the gap between the electrode substrates can be made slightly smaller within the range of the present invention, and the driving voltage can be reduced.

The liquid crystal display element and the liquid crystal display device of the present invention may be further laminated with an infrared cut filter, an ultraviolet cut filter, etc., or may print characters, figures, or the like,
A plurality of liquid crystal display elements may be used.

Further, in the present invention, a protective plate such as a glass plate or a plastic plate may be laminated outside the liquid crystal display element. Thereby, even if the surface is pressurized, the risk of breakage is reduced, and safety is improved.

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

Specifically, a photocurable acrylic resin is exemplified, and a resin containing an acrylic oligomer which is polymerized and cured by light irradiation is particularly preferable.

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

When a photocurable resin is used as the liquid crystal used in the liquid crystal resin composite, it is preferable that the photocurable resin is uniformly dissolved, and the cured product after light exposure does not dissolve. Alternatively, when the composition is used, it is desirable that the solubility of each liquid crystal is as close as possible.

When manufacturing a liquid crystal resin composite, an active matrix substrate and a counter electrode substrate are arranged so that the electrode surfaces face each other as in a conventional ordinary liquid crystal display element, the periphery is sealed with a sealing material, and an injection port is formed. A liquid mixture for an uncured liquid crystal resin composite may be injected from above to seal the injection port, or a mixture of a curable compound and liquid crystal may be supplied on a substrate, and the opposing substrates may be overlapped. May be manufactured.

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

In the present invention, the liquid crystal is used as a solvent as the liquid crystal resin composite, and the photocurable resin is cured by light exposure, so that there is no need to evaporate a mere solvent or water that is unnecessary at the time of curing. For this reason, since it can be cured in a closed system, the conventional manufacturing method of injection into a cell can be employed as it is, and it has high reliability and also has an effect of bonding two substrates with a photocurable resin. The nature becomes high.

By using the liquid crystal resin composite in this way, the risk of short circuit between the upper and lower transparent electrodes is low, and there is no need to strictly control the orientation and the substrate gap as in a normal TN type display element, so that transmission is possible. A liquid crystal display element capable of controlling the state and the scattering state can be manufactured with extremely high productivity.

In this liquid crystal display element, when the substrate is made of plastic or thin glass, a protective plate made of plastic, glass, or the like is preferably laminated on the outside for further protection.

In the liquid crystal display device of the present invention, when a voltage is applied for driving, the maximum effective voltage equal to or less than the maximum effective voltage of the above formula (5), usually the maximum effective voltage described above, is applied to the liquid crystal resin composite between the electrodes of the pixel. It may be driven so that:

As the color light source of the present invention, the projection optical system, the projection screen for projection, etc., a conventional light source, projection optical system, projection screen can be used, and the active matrix liquid crystal display element of the present invention is provided between the color light source and the projection optical system. It should just be arranged. In this case, the projection optical system may combine the images of a plurality of active matrix liquid crystal display elements using the optical system as shown in FIG. 1 and then project the images, or as shown in FIG. The images of the matrix liquid crystal display elements may be individually projected onto a projection screen and synthesized on the projection screen. In these cases, the color light source is also 1 in the above example.
Although the light is separated from one light source, a plurality of light sources of a plurality of colors may be separately provided in advance to be incident on the liquid crystal display element.

In the case of projecting with one liquid crystal display element using a color filter, light from one projection light source is made incident on the liquid crystal display element, and the emitted light is projected on a projection screen by a projection optical system. What should be done is.

Light sources used for these projection light sources include a halogen lamp, a metal halide lamp, a xenon lamp, and the like, and light utilization efficiency can be increased by combining a concave mirror, a condenser lens, and the like.

Further, a cooling system may be added thereto, an infrared cut filter or an ultraviolet cut filter may be used in combination, or a channel display such as an LED may be added.

In particular, in the case of this projection type display, a device for reducing the diffused light on the optical path, for example, 9, 19A, 19 in FIGS.
By providing apertures and spots as shown in B and 19C, the display contrast can be increased.

That is, as a device for reducing diffused light, of light that has passed through a liquid crystal display element, light that goes straight to incident light (light that passes through a portion where a pixel portion is in a transmission state) is extracted, and light that does not go straight (liquid crystal resin composite). Light scattered in the part where the body is in the scattering state)
It is preferable to use a material that reduces the contrast in order to improve the contrast ratio. In particular, it is preferable to reduce the light that does not go straight (scattered light, in other words, the diffused light) without reducing the light that goes straight.

The device for reducing the diffused light may be provided between the projection optical system and the projection screen as shown in FIGS. 1 and 2, or the projection optical system may include a plurality of projection optical systems. When it is composed of lenses, it may be arranged between the lenses.

The device for reducing the diffused light is not limited to the aperture and the spot as described above, and may be, for example, a small-area mirror arranged on the optical path.

The ratio between the straight component and the scattering component reaching the projection screen can be controlled by the diameter of a spot, a mirror or the like and the focal length of a lens, and may be set so as to obtain desired display contrast and display luminance.

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

[Operation] According to the present invention, a display having a good color balance, a high display luminance, and a high contrast ratio, in particular, a projection type display can be obtained.

Particularly, in the present invention, since the active matrix liquid crystal display element sandwiching the liquid crystal resin composite having specific characteristics corresponding to the color of the light source as described above is used, the balance of each color is good, and a special correction is required for the driving circuit. Conventional TN technology enables beautiful gradation display of colors without incorporating a circuit, and the applied maximum effective applied voltage can be reduced to 10 V or less.
Active devices and driving ICs used for the active matrix liquid crystal display device of the type can be easily used.

[Examples] Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 Chromium on a glass substrate (Corning 7059 substrate)
60 nm was deposited and patterned to form a gate electrode. Subsequently, a silicon oxynitride film and an amorphous silicon film were deposited by a plasma CVD apparatus. This was annealed using a laser and then patterned to obtain polycrystalline silicon. Then, phosphorus-doped amorphous silicon and chromium were deposited using plasma CVD and a vapor deposition apparatus, respectively, and were patterned so as to cover the polycrystalline silicon, thereby forming a first layer source electrode and drain electrode. Further, after depositing ITO, patterning was performed to form a pixel electrode. Subsequently, chromium and aluminum were continuously vapor-deposited and patterned so as to connect the pixel electrode with the first-layer source electrode and drain electrode, thereby forming a second-layer source electrode and drain electrode. Thereafter, the silicon oxynitride film is again plasma-treated.
An active matrix substrate was prepared by depositing a protective film using a CVD apparatus.

A counter electrode substrate made of the same glass substrate with a solid ITO electrode formed on the entire surface and an active matrix substrate manufactured earlier are placed so that the electrode surfaces face each other, and a spacer with a diameter of about 11.0 μm is scattered inside. except inlet section and its vicinity, and sealed with a sealant of epoxy, substrate gap d _G was prepared empty cell of approximately 11.0 .mu.m.

6 parts of 2-ethylhexyl acrylate, 18 parts of hydroxyethyl acrylate, 20 parts of an acrylic oligomer (“M-1200” manufactured by Toa Gosei Chemical Co., Ltd.), 0.4 parts of “Darocur 1116” manufactured by Merck as a photocuring initiator, and liquid crystal And 62 parts of "E-8" manufactured by BDH were uniformly dissolved.

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

This was irradiated with ultraviolet rays for 60 seconds to cure the liquid crystal resin composite, thereby producing an active matrix liquid crystal display element for green display.

The average particle diameter R of the liquid crystal in the liquid crystal resin composite of the liquid crystal display element thus prepared is about 1.9 μm, and the refractive index anisotropy Δn of the liquid crystal.
Was about 0.24 and the dielectric anisotropy Δε was about 15.6.

Similarly, an active matrix liquid crystal display element for red display was produced. The average particle size R of this liquid crystal is about 1.9 μm.
m, the substrate gap d _R was about 12.0 .mu.m.

Similarly, an active matrix liquid crystal display element for blue display was produced. The average particle size R of this liquid crystal is about 1.9 μm.
m, the substrate gap d _B was about 10.0 [mu] m.

When the voltage-transmittance characteristics of these liquid crystal display elements were measured for each color, the characteristics were almost the same.

Using these three liquid crystal display elements, a projection type display device is configured with the configuration shown in FIG. 1, a video signal is input to a drive circuit, and the voltage applied to the liquid crystal resin composite is 8 V in effective value. And a projection image was projected on a projection screen.

As a result, a full-color moving image display image without an afterimage is obtained, the display is almost color-balanced at each gradation, and the contrast ratio on the projection screen is 80%.
The above bright display was obtained.

The contrast ratio of the image projected on the projection screen was about 40 when no aperture as a device for reducing diffused light was used.

Comparative Example 1 Three liquid crystal display elements for green of Example 1 were prepared, and they were combined with a three-color light source of RGB to construct a projection display device similar to that of Example 1.

The display obtained by this projection type display device was a reddish image as a whole, and the tendency was particularly remarkable in halftone display. When no electric field was applied to any of the three liquid crystal display elements, the projection screen turned dark red instead of black. This is thought to be due to the difference in the threshold voltage characteristics of the liquid crystal depending on the RGB.
Investigation of the applied voltage-transmittance characteristics for each B revealed that in the halftone region, at the same applied voltage, R had the highest transmittance and B had the lowest.

Substrate gap d _R of the Comparative Example 2 three liquid crystal display elements, d _G, carrying out the d _B Example 1
The average particle diameter R of the liquid crystal was set to 3.0 μm in the same manner as described above.
These were combined with RGB three-color light sources to construct a projection display device similar to that of Example 1.

The display obtained by this projection display device was bright, but only a display having a low contrast ratio of about 10 was obtained.

Example 2 Using the same liquid crystal display element as in Example 1, a projection type display device having the configuration shown in FIG. 2 was formed. This projection type display device also had a good color balance similar to that of Example 1, and a bright display having a high contrast ratio was obtained.

Example 3 Three color filters of RGB were formed on a counter electrode substrate, and a counter electrode of ITO was formed thereon. At this time, when the thickness of the color filter is changed and combined with the active matrix substrate, 1
The electrode gap was set to 2.0 μm, the electrode gap for green pixels was set to 11.0 μm, and the electrode gap for blue pixels was set to 10.0 μm. The average particle size R of the liquid crystal was 1.9 μm, which was almost uniform.

When a video signal was input to the drive circuit of the liquid crystal display element and the liquid crystal resin composite was driven so that the voltage applied to the liquid crystal resin composite became an effective value of 8 V, a bright display with good color balance was obtained.

The liquid crystal display element, the white light source, the projection optical system, and the aperture are combined to form a projection display device, and when a projected image is projected on a projection screen, a bright, high contrast ratio, color-balanced display is obtained. Was done.

Example 4 The TFT was a TFT using an inverted stagger type amorphous (amorphous) silicon, the substrate side was shielded from light by a gate electrode, and the liquid crystal side was shielded from light by providing a light-shielding film via an insulating film.
Three types of active matrix liquid crystal display elements were manufactured in the same manner as in Example 1.

When a projection type display was constructed using these liquid crystal display elements, the same display as in Example 1 was obtained. However, the liquid crystal display element of this embodiment requires an extra step of forming a light shielding film. Further, if the light shielding film has a defect, the display is affected.

[Effects of the Invention] In the active matrix liquid crystal display device of the present invention, the display color balance is good, and the drive circuit does not need to correct the drive waveform for each color, and the drive becomes easy.

Further, since the average particle diameter R of the liquid crystal in the liquid crystal resin composite may be kept constant, the productivity is good, and color display can be performed with one liquid crystal display element by using a color filter together. Since the liquid crystal resin composite and the active matrix liquid crystal display element of the present invention can control the separation state of the resin matrix and the dispersed liquid crystal with high accuracy, the optical characteristics of the scattering state and the transmission state can be improved, and excellent display can be obtained. Was done.

In the projection type active matrix liquid crystal display device of the present invention, as a liquid crystal material sandwiched between the active matrix substrate and the counter electrode substrate, a liquid crystal resin composite capable of controlling an electrically scattering state and a transmission state is sandwiched. Since a liquid crystal display element is used, a polarizing plate is not required, the light transmittance at the time of transmission can be greatly improved, and a bright projected image can be obtained.

The liquid crystal display element of the present invention has a high scattering property in a state where no electric field is applied, and has a high transparency in a state where an electric field is applied by an active element. Even in driving using an IC, a display having a high contrast ratio and high luminance can be performed.

Further, in the present invention, since the characteristics of the liquid crystal display element are optimized for each color of the color light source, a display with good color balance can be obtained even in a halftone.

In addition, since it is not necessary to use a polarizing plate, there is an advantage that the wavelength dependence of optical characteristics is small, and color correction of a light source is almost unnecessary.

In addition, since problems such as alignment treatment such as rubbing, which is indispensable for a TN type liquid crystal display element, and destruction of an active element due to generation of static electricity accompanying the rubbing can be avoided, the production yield of the liquid crystal display element can be greatly improved.

Further, since the liquid crystal resin composite is in the form of a film after curing, problems such as short-circuiting between substrates due to pressurization of the substrates and destruction of the active element due to movement of the spacer hardly occur.

In addition, this liquid crystal resin composite has the same specific resistance as that of the conventional TN mode, and does not require a large storage capacitor for each pixel electrode as in the conventional DS mode, making it easy to design active elements. Thus, the ratio of the effective pixel electrode area can be easily increased, and the power consumption of the liquid crystal display element can be kept low.

Further, since the manufacturing process of the conventional TN mode liquid crystal display element can be performed only by removing the alignment film forming step, the production is easy.

In addition, a liquid crystal display device using this liquid crystal resin composite
It also has the feature that the response time is short, and it is easy to display moving images. Furthermore, the electro-optical characteristics (voltage-transmittance) of this liquid crystal display element are comparatively gentle compared to the TN mode liquid crystal display element, so that application to gradation display is easy.

Further, in the liquid crystal display element of the present invention, since light is scattered in a portion where no electric field is applied, there is no light leakage at the time of projection even if a portion other than the pixel is not shielded by a light shielding film, and a gap between adjacent pixels is reduced. No need to shade. Therefore, in particular, by using an active element made of polycrystalline silicon as the active element, a high-brightness projection light source can be used without a light-shielding film in the active element portion, and a high-brightness projection type liquid crystal display device can be easily manufactured. Obtainable. Further, in this case, no light-shielding film needs to be provided, and the production process can be further simplified.

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]

1 and 2 are schematic views showing the configuration of a basic example of a projection type active matrix liquid crystal display device of the present invention. FIG. 3 is a sectional view showing a basic configuration of an active matrix liquid crystal display element used in the present invention. FIG. 4 is a sectional view showing a basic configuration of an active matrix liquid crystal display device provided with a color filter used in the present invention. Light source: 1,11 Concave mirror: 2, 12 Condenser lens: 3, 13 Dichroic prism for spectrum: 4 Mirror: 5A, 5B, 5C, 5D Active matrix liquid crystal display device: 6A, 6B, 6C, 16A,
16B, 16C, 21, 31 Dichroic prism for synthesis: 7 Projection lens: 8, 18A, 18B, 18C Aperture: 9, 19A, 19B, 19C Projection screen: 10, 20 Dichroic mirror: 15A, 15B, 15C Substrate: 22, 25, 32, 35 Pixel electrode: 23, 33 Active element: 24, 34 Counter electrode: 26, 36 Liquid crystal resin composite: 27, 37 Color filter: 38

Claims (6)

(57) [Claims] 1. A projection type having a plurality of color light sources, a plurality of active matrix liquid crystal display elements on which light from each color light source is incident, and a projection optical system for combining and projecting light emitted from the active matrix liquid crystal display elements. In an active matrix liquid crystal display device, a nematic liquid crystal having a positive dielectric anisotropy is provided between an active matrix liquid crystal display element provided with an active element for each pixel electrode and a counter electrode substrate provided with a counter electrode. A liquid crystal resin composite dispersed and held in a resin matrix is sandwiched, and the refractive index of the resin matrix is the ordinary light refractive index (n _o ) of the liquid crystal used.
The liquid crystal used has a refractive index anisotropy Δn of 0.18 or more, an average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, and a gap between both electrodes of each color.
d _X (μm), the gap d _G between both electrodes when the main wavelength λ _X of the color of each light source is the main wavelength λ _G = 540 nm of the green light source
0.3 <R · Δn <0.7 (1) 4 R <d _G <8R (2) A projection type active matrix liquid crystal display device characterized by satisfying the following relationship: Wherein RGB3 color light sources and three active matrix liquid crystal display device is provided, both electrode gap d _R of the liquid crystal display device of the three colors, d _G, d _B, the dominant wavelength λ of the color of each light source _R ,
λ _G and λ _B are 2. The projection type active matrix liquid crystal display device according to claim 1, wherein the following relationship is satisfied. 3. An active matrix liquid crystal display device having a plurality of color filters, wherein a dielectric anisotropy is provided between an active matrix substrate provided with an active element for each pixel electrode and a counter electrode substrate provided with a counter electrode. Is used to sandwich a liquid crystal resin composite in which a positive nematic liquid crystal is dispersed and held in a resin matrix, so that the refractive index of the resin matrix substantially matches the ordinary light refractive index (n _o ) of the liquid crystal used. The refractive index anisotropy Δn of the liquid crystal is 0.18 or more, the average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, the gap d _X (μm) between both electrodes of each color, and the transmission light of each color filter. 0.3 <R · Δn <0.7 (1) 4 R <d _G <8R (for the gap d _G (μm) between both electrodes when the main wavelength λ _X is the main wavelength λ _G = 540 nm of the green light source) 2) An active matrix liquid crystal display device characterized by satisfying the following relationship: 4. An active matrix liquid crystal display element having three color filters of RGB is provided, and the electrode gaps d _R , d _G , and d _{B of} the liquid crystal display element corresponding to the color filter parts of three colors are provided. Dominant wavelength λ of transmitted light
_R , λ _G , λ _B are 4. The active matrix liquid crystal display device according to claim 3, wherein the following relationship is satisfied. 5. A nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a resin matrix between an active matrix substrate provided with an active element for each pixel electrode and a counter electrode substrate provided with a counter electrode. The liquid crystal resin composite is sandwiched, the refractive index of the resin matrix is made to substantially match the ordinary refractive index (n _o ) of the liquid crystal used, and the refractive index anisotropy Δn of the liquid crystal used is 0.18 or more; The resin matrix is 2-
An active matrix liquid crystal display device formed by curing a solution containing ethylhexyl acrylate, hydroxyethyl acrylate, an acrylic oligomer, and a photo-curing initiator. 6. A liquid crystal resin composite in which a nematic liquid crystal having a positive dielectric anisotropy is dispersed and held in a resin matrix, and is sandwiched between a pair of substrates with electrodes. The refractive index anisotropy Δn of the liquid crystal used is made to substantially match the ordinary refractive index (n _o ) of the liquid crystal to be used.
0.18 or more, the average particle diameter R (μm) of the liquid crystal dispersed and held in the resin matrix, and the gap d _X (μm) between both electrodes
And the main wavelength λ _X of the color of the light source is the main wavelength λ of the green light source.
0.3 <R · Δn <0.7 (1) 4 R <d _G <8R (2) For the gap d _G (μm) between both electrodes when _G = 540 nm. Liquid crystal resin composite that satisfies the above relationship.