JPH11142823A - Liquid crystal shutter and color image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal color shutter of high transmittance, high- speed response and wide visual field angle, a color image display device using the same and more particularly a color image display device of a field sequential system. SOLUTION: Liquid crystal molecules are stabilized by the intermolecular force with a polymeric substance or the plural states larger than a spiral pitch P0 of a natural state are made to cause transition, by which an electro-optic response speed and more particularly a response speed in a relaxation process are speeded up. For example, the electric field to be impressed on the liquid crystal layer (13) is so controlled that the plural states (for example, Pi=P1 , Pi=P2 , etc.), larger than the natural spiral pitch of the liquid crystal molecules 13a correspond to the wavelength of the light which is transmitted through the liquid crystal layer (13) or selectively reflected by the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal shutter such as a liquid crystal color shutter. The invention also relates to a color image display device that displays a color image using a liquid crystal shutter.

[0002]

2. Description of the Related Art With the advancement of multimedia information, research and development of a new thin and large screen display has been actively pursued in order to realize a wall-mounted TV, a home theater, and the like. Typical examples of such a display include a plasma display (ΡDΡ) and a plasma addressing liquid crystal display (ΡALC), and the former is already commercially available. However, display devices such as PDP, PALC, etc.
In terms of manufacturing cost, resolution, brightness, etc., conventional fluorescent tubes (CR
At present, it does not reach T).

On the other hand, as a large-screen display using fluorescent tubes, a display device has been proposed which realizes a large-screen display by arranging a plurality of small fluorescent tubes side by side. When a color fluorescent tube is used in such a display device, color shift occurs, the resolution is limited by the arrangement pitch of the phosphors,
There are problems such as individual differences in hue, and an increase in manufacturing costs due to high-precision members such as shadow masks and three electron guns. In the black-and-white fluorescent tube, a display method of performing color display by combining the black-and-white fluorescent tube and a liquid crystal color shutter has been proposed because the above-described problems with the color fluorescent tube do not occur. This display method is called a field sequential method, and the display colors (for example, red, green, blue, etc.) of the entire screen are switched at high speed by a liquid crystal color shutter, and each display is synchronized with the switching of the display color of the liquid crystal color shutter. An image having a gradation corresponding to a color is displayed by a black-and-white fluorescent tube (for example, Proc. SID2).
6, 157 (1985)). A small color display using a single black-and-white fluorescent tube and a liquid crystal color shutter has been partially commercialized.

The performance required of the liquid crystal color shutter used in the field sequential system is high transmittance, high speed response, and wide viewing angle. Conventionally, a liquid crystal color shutter used in a field sequential system is composed of a plurality of color polarizers (three in the case of RGB color polarizers and five in the case of CMY color polarizers) and two liquid crystal shutters. ing. For this reason, the theoretical maximum value of the transmittance is at most 1
6.7% and less than about 6% in actual prototypes (Proc. SID26,
157 (1985)). As the liquid crystal shutter, a π-cell type nematic liquid crystal, a ferroelectric liquid crystal (FLCD), an antiferroelectric liquid crystal (AFLCD), and the like are used. The response speed of a π-cell type nematic liquid crystal is about 1.7 ms (Pro
c. SID 26, 157 (1985)), which is insufficient from the viewpoint of suppressing color flicker. Although (anti) ferroelectric liquid crystals are high-speed, alignment breakdown is likely to occur, and measures must be taken to prevent this. There is a problem.

In order to ensure high transmittance, a method without using a color polarizing plate may be adopted, but in this case, the liquid crystal shutter itself needs to control the color. Such systems include a guest-host liquid crystal system and a cholesteric liquid crystal system. In the guest-host liquid crystal system, color control is performed by controlling the orientation of a dichroic dye by using liquid crystal. However, there are problems in response speed, light resistance of the dye, two-color ratio of the dye, and the like.
The cholesteric liquid crystal system utilizes a selective reflection phenomenon in a planar structure. The selective reflection phenomenon, in the wavelength range around the wavelength lambda defined by the cholesteric λ = n × Ρ ₀ and the average refractive index n is a natural helical pitch length [rho ₀ of the liquid crystal, the circularly polarized light component of the spiral in the same direction It is reflective.

[0006] Among the cholesteric liquid crystal systems, a system for switching between a planar structure in a selective reflection state and a homeotropic structure in a transmission state has a low transition speed of about 100 ms from the homeotropic structure to the planar structure (SID95DIGEST 351 (1995)). Therefore, there is a problem in using it for a liquid crystal shutter of a field sequential type color display device.

In the method of controlling the selective reflection wavelength region by controlling the helical pitch length of the planar structure of the cholesteric liquid crystal, a higher-speed response can be expected because the process of the slow structural change is not performed. With respect to a method of controlling the helical pitch length of a cholesteric liquid crystal by an electric field, a method applied to a reflection type color liquid crystal display device is proposed in Japanese Patent Application Laid-Open No. 7-209662. Among them, there is an example of realizing a reflective color display by switching three primary colors of light at high speed. However, as a result of studies by the present inventors, at the driving frequency described in the embodiment of this document, color flicker is reduced. Then, it was found that there was an extremely large problem in display quality. As a result of further study, it is necessary to switch display colors in about 1 ms or less in order to suppress color flicker and obtain high display performance.
It has been found that such a fast response cannot be realized by the method disclosed in 209662. The relaxation process from a planar structure with a longer pitch length to a planar structure with a shorter pitch length is a process that cannot be controlled by voltage, so the transition speed is slower than the reverse process. Must be taken.

In considering the application to a field sequential type color display device, it has been found that the method disclosed in JP-A-7-209662 further has the following problem. In other words, in this method, the color selection in transmitted light is the three primary colors of subtractive color mixture, the color reproducibility in additive color mixture is narrow, and the right-handed and left-handed liquid crystal layers are used to increase light use efficiency. However, it is difficult to obtain dextrorotatory and levorotatory optical isomers with chiral agents, and the flexibility of material selection is low, and different liquid crystal layers, right-handed and left-handed, are prepared. The cost is high, the temperature dependence of the pitch length is large, and the display color changes depending on the operating temperature, and unnecessary light is not specified because the spectrum of the incident light and the wavelength region of the selective reflection are not specified. However, there is a problem that the color purity is lowered due to the transmission of light.

Finally, regarding the viewing angle. The selective reflection of the cholesteric liquid crystal has a large dependence of the polar angle on the viewing angle, but has no dependence on the azimuth angle. Therefore, there is an advantage that viewing angle compensation can be easily performed as compared with the case where a color polarizing plate and a π-cell type nematic liquid crystal are used.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a liquid crystal shutter having a high transmittance, a high response speed, and a wide viewing angle, and a color image display device using the same. Further, the present invention provides a liquid crystal shutter having high color reproducibility in additive color mixture, a large degree of freedom in material selection, low cost, stable display colors, and high color purity, and a color image display device using the same. The purpose is to do.

[0011]

In order to solve such a problem, the present invention has the following arrangement. A liquid crystal shutter according to the present invention includes a liquid crystal layer exhibiting a cholesteric phase sandwiched between a first substrate and a second substrate, and a liquid crystal layer provided on the liquid crystal layer in a plane direction of the first substrate and the second substrate. Between the first substrate and the second substrate, and an intermolecular force acting between the liquid crystal molecules forming the liquid crystal layer. And a polymer composition disposed so as to be the largest at a helical pitch P ₀ . In order to stabilize the helical pitch P ₀ of the liquid crystal molecules constituting the liquid crystal layer, for example, in a state where the helical pitch of the liquid crystal molecules Ρ ₀ ,
By polymerizing a polymerizable substance coexisting with the liquid crystal layer,
A polymer (polymeric substance) may be dispersed in the liquid crystal layer.

Further, the liquid crystal shutter of the present invention comprises: a liquid crystal layer exhibiting a cholesteric phase sandwiched between a first substrate and a second substrate; and a spiral of liquid crystal molecules constituting the liquid crystal layer is provided on the liquid crystal layer. means pitch applying a first electric field such that the helical pitch P ₁ larger first than the natural helical pitch P _0, the liquid crystal layer, the helical pitch of the first helical pitch P of the liquid crystal molecules Means for applying a second electric field so as to have a _second helical pitch P2 larger than _one .

Further, the liquid crystal shutter of the present invention is characterized in that a liquid crystal layer exhibiting a cholesteric phase in which the wavelength of the selectively reflected light is in the ultraviolet region is sandwiched between the first substrate and the second substrate. For example, the liquid crystal shutter of the present invention has the first
A liquid crystal layer exhibiting a cholesteric phase sandwiched between the first and second substrates, and means for applying an electric field to the liquid crystal layer in a direction parallel to a plane direction of the first substrate and the second substrate. And the arrangement may be such that when the electric field is not applied, the wavelength of the selectively reflected light of the liquid crystal layer is in an ultraviolet region.

Further, the liquid crystal shutter of the present invention comprises a liquid crystal layer exhibiting a cholesteric phase sandwiched between a first substrate and a second substrate, and a spiral of liquid crystal molecules constituting the liquid crystal layer is provided on the liquid crystal layer. means pitch applying a first electric field such that the helical pitch P ₁ larger first than the natural helical pitch P _0, the liquid crystal layer, the helical pitch of the first helical pitch P of the liquid crystal molecules means for applying a second electric field such that the helical pitch P ₂ of the larger second than _1, between the first substrate and the second substrate,
A polymer composition disposed such that an intermolecular force acting between the liquid crystal molecules and the liquid crystal molecules is maximized in a region of a natural helical pitch P ₀ or less.

The liquid crystal shutter of the present invention is not limited to a single liquid crystal layer, but is used by laminating a plurality of liquid crystal layers, for example, by laminating a plurality of liquid crystal layers having different helical directions of a cholesteric phase. You may do so. For example, when the liquid crystal layers to be combined have the same helical orientation, λ
A / 2 plate (phase difference plate) may be used in combination. Also, for example, when the spiral directions of the liquid crystal layers to be combined are the same, a polarization conversion sheet that converts non-polarized light into right-handed circularly polarized light or left-handed circularly polarized light has the same helical direction as the converted circularly polarized light direction and the cholesteric liquid crystal phase. What is necessary is just to combine so that it may become.

[0016] The color image display device of the present invention comprises: means for displaying an image having a gradation corresponding to color information on a display screen;
A liquid crystal shutter according to any one of claims 1, 2, 3, and 4 provided on the display screen. That is, the color image display device of the present invention includes a means for displaying an image having a gradation corresponding to color information on a display screen, and a means for disposing the first substrate and the second substrate on the display screen. A liquid crystal layer presenting a cholesteric phase sandwiched therebetween, means for applying an electric field to the liquid crystal layer in a direction parallel to the first substrate and the second substrate, the first substrate and the second between the substrate, and a polymer composition disposed as best becomes large when the natural helical pitch P ₀ of the intermolecular forces the liquid crystal molecules acting between the liquid crystal molecules constituting the liquid crystal layer And a liquid crystal shutter. Further, the color image display device of the present invention is a device for displaying, on a display screen, an image having a gradation corresponding to color information, and provided between the first substrate and the second substrate provided on the display screen. A liquid crystal layer exhibiting a cholesteric phase and a first helical pitch P in which the helical pitch of liquid crystal molecules constituting the liquid crystal layer is larger than the natural helical pitch P _0.
Means for applying a first electric field to be _1, the liquid crystal layer, the said as the helical pitch of the liquid crystal molecules is the helical pitch P ₂ of the larger second than the first helical pitch P ₁ And a liquid crystal shutter having means for applying an electric field. Further, the color image display device of the present invention is a device for displaying, on a display screen, an image having a gradation corresponding to color information, and provided between the first substrate and the second substrate provided on the display screen. And a liquid crystal shutter sandwiching a liquid crystal layer exhibiting a cholesteric phase in which the wavelength of the selectively reflected light is in the ultraviolet region.

Further, the color image display device of the present invention comprises a means for displaying an image having a gradation corresponding to color information on a display screen, a first substrate and a second substrate provided on the display screen. a liquid crystal layer exhibiting a cholesteric phase that is sandwiched between, on the liquid crystal layer, so that the helical pitch of the liquid crystal molecules constituting the liquid crystal layer becomes great first helical pitch P ₁ than the natural helical pitch P ₀ a means for applying a first electric field to the liquid crystal layer, a second electric field to the helical pitch is the helical pitch P ₂ of the larger second than the first helical pitch P ₁ of the liquid crystal molecules An application means, and an intermolecular force acting between the liquid crystal molecules and the first substrate being arranged between the first substrate and the second substrate so that the intermolecular force acting on the liquid crystal molecules becomes maximum at a natural helical pitch P ₀ of the liquid crystal molecules. Liquid crystal panel comprising the polymer composition And a jitter.

Further, it is preferable that the spectrum of the light emitted from the display screen corresponds to the selective reflection spectrum of the liquid crystal layer constituting the liquid crystal shutter.

The display means may be any means capable of performing gradation display on a display screen, and for example, a CRT or the like can be used. By synchronizing the timing of changing the display color of the liquid crystal shutter with the modulation timing of the color information (color gradation information) of the image displayed on the display screen, for example, a monochrome or gray scale CRT is used to produce a color image. Can be displayed. Further, in order to obtain a larger display screen, a plurality of display screens may be used in combination. For example, not only a single CRT but also a plurality of CRTs may be combined to form a continuous display screen.

In any case, it is preferable that the emission spectrum of the display means such as a fluorescent tube and the selective reflection spectrum of the liquid crystal layer constituting the liquid crystal shutter are combined and arranged so as to overlap.

That is, the liquid crystal shutter of the present invention applies an electric field (transverse electric field) in a direction parallel to the substrate surface to the liquid crystal layer exhibiting a cholesteric phase sandwiched between the substrates, so that the liquid crystal molecules constituting the liquid crystal layer are formed. The color image display device of the present invention controls the wavelength of transmitted light or (selectively) reflected light by changing the helical pitch, and realizes high transmittance, high-speed response, and a wide viewing angle. Is a display device for displaying a color image using such a liquid crystal shutter of the present invention. The liquid crystal shutter of the present invention includes, for example, a pair of substrates arranged opposite to each other, a liquid crystal layer exhibiting a cholesteric phase sandwiched between the substrates, and a means for applying an electric field parallel to the substrate to the liquid crystal layer. Have,
By modulating the helical pitch length of the liquid crystal molecules constituting the liquid crystal layer at a high speed of about 1 ms or less by the electric field, the wavelength of the selectively reflected light of the liquid crystal layer or the transmitted light of the liquid crystal layer (for example, 3 wavelengths such as red, green, and blue). (Primary colors) can be switched at high speed.

For this reason, in the liquid crystal shutter of the present invention, by stabilizing the helical pitch of the cholesteric liquid crystal or the chiral nematic liquid crystal in the natural state, a state in which the helical pitch is longer than P ₀ (P ₁ > P ₀ ).
The speed of the relaxation process has been increased. For example, by coexisting a liquid crystal layer and a polymer substance so that the liquid crystal molecules are most stable when the liquid crystal molecules have a helical pitch length P ₀ , the energy difference from a state where the helical pitch is longer than P ₀ is increased. The helical pitch length P from the state of the helical pitch length P _1
Since the relaxation time to the state of ₀ is inversely proportional to the energy difference between the two states having different pitch lengths, stabilizing the state of the helical pitch length P ₀ increases the relaxation speed, thereby increasing the operation speed of the liquid crystal shutter. Can be speeded up.

[0023] In the liquid crystal shutter of the present invention, cholesteric liquid crystal or between the chiral nematic liquid crystal of natural helical pitch than the helical pitch P ₀ in the state is long plurality of states (e.g., the helical pitch P ₁ anthracene pitch P ₂
, The wavelengths of the transmitted light and the reflected light are controlled by transitioning P ₀ <P ₁ <P ₂ ). The elastic energy of the liquid crystal molecules is the smallest in the natural state P ₀ , and has a greater elastic energy in a state where the pitch is longer than this. Thus, for example, from a large second helical pitch P ₂ than the helical pitch P ₀ of the natural state, the relaxation rate in the first helical pitch P ₁ (P ₁ <P ₂₎ to speed, shorten the time required for transition can do.

In the liquid crystal shutter of the present invention having such a configuration, for example, a plurality of states larger than the natural helical pitch of the liquid crystal molecules are made to correspond to the wavelength of transmission or selective reflection (for example, B (blue) is changed to P ₁ ). , G (green) to P ₂ ,
Let R (red) correspond to P ₃ , P ₁ , P ₂ , P ₃ is P ₀
Therefore, the state of the helical pitch P ₀ corresponds to the shorter wavelength side (violet outside) than blue. Therefore, in the liquid crystal shutter of the present invention, for example, the wavelength of the selectively reflected light in the state where no voltage is applied is shifted to the ultraviolet outside of the visible region. By configuring the cell in this way, the wavelength control of the transmitted light and the selectively reflected light can be actually performed by transitioning between states having higher elastic energy than the natural state.

Further, in the present invention, the above two structures, namely, a structure in which the relaxation process is accelerated by stabilizing the liquid crystal molecules by the intermolecular force with the polymer substance, and a structure in which the spiral pitch P _{0 in the} natural state is used. The liquid crystal shutter may be configured in combination with a configuration in which the relaxation speed is increased by transiting a plurality of large states. For example, the helical pitch of the liquid crystal molecules when controlling the wavelengths of the transmitted light and the selectively reflected light is made longer than P ₀ so that the elastic energy in the liquid crystal molecules is larger (in this case, the spiral of the natural state of the liquid crystal molecules) The wavelength of the selectively reflected light corresponding to the pitch P ₀ is shifted to the ultraviolet side from the visible region), and the state of the helical pitch P ₀ is stabilized by dispersing a polymer substance or the like. You may make it. By doing so, the relaxation time of the helical pitch of the liquid crystal molecules when controlling the wavelengths of the transmitted light and the selectively reflected light is further shortened, and the electro-optical response can be made faster.

A color image display device according to the present invention comprises a liquid crystal shutter according to the present invention having the above-described configuration, and a liquid crystal shutter for displaying an image having a gradation corresponding to color information on a display screen.
It is a display device combining RT and the like. For example, by disposing the liquid crystal shutter of the present invention on the display screen of a CRT for displaying black and white (gray scale) and synchronizing the timing of luminance modulation with the timing of switching the display color of the liquid crystal shutter, the liquid crystal shutter is displayed on the display screen. Image can be displayed as a color image.

As the material constituting the liquid crystal layer of the liquid crystal shutter of the present invention, any material can be used as long as a liquid crystal layer exhibiting a cholesteric phase can be obtained. Further, the liquid crystal material is not limited to a single liquid crystal material, and two or more liquid crystal materials may be used in combination, or a mixture containing a material other than liquid crystal may be used. Examples of a constituent material of such a liquid crystal layer include a cholesteric liquid crystal and a mixture of a nematic liquid crystal and a chiral agent. Further, the liquid crystal isotropic phase transition temperature of the liquid crystal layer to be used needs to be higher than the maximum temperature at the time of operating the liquid crystal shutter of the present invention and the color image display device using the same. Therefore, the liquid crystal isotropic phase transition temperature of the liquid crystal layer is preferably set to, for example, about 60 ° C. or more, more preferably about 85 ° C.
What is necessary is just to set more than about. On the other hand, the crystal-liquid crystal transition temperature of the liquid crystal layer needs to be lower than the minimum temperature at which the liquid crystal shutter of the present invention and the color image display device using the same operate. Therefore, the crystal-liquid crystal transition temperature of the liquid crystal layer is preferably set to, for example, about −10 ° C. or less, and more preferably about −40 ° C. or less.

From the viewpoint of realizing color switching within about 1 ms or less, which is essential for suppressing color flicker, it is preferable to set the torsional elasticity coefficient K ₂₂ of the liquid crystal to about 5 pN or more. More preferably, it is set to about 6 pN or more. Similarly, the rotational viscosity coefficient γ of the liquid crystal
Is preferably set smaller than about 200 mPa · s, and more preferably set smaller than about 150 mPa · s. Further, the average refractive index n of the liquid crystal is preferably set to be larger than about 1.5, and more preferably set to be larger than about 1.55.

The half width Δλ of the selective reflection spectrum of the liquid crystal layer
Is represented by Δλ = Δn × P. When a color image display device is configured by combining the liquid crystal shutter of the present invention with a black-and-white fluorescent tube, red, green,
Since each color of blue is selected, it is preferable to set Δn so that the selective reflection spectrum of the liquid crystal shutter sufficiently covers the spectrum width of the emission spectrum of the phosphor.

Further, from the viewpoint of suppressing the shift of the display color due to the temperature change, it is preferable to use a liquid crystal material having high stability with respect to the temperature change of the display color, that is, a material having a small dependence of the helical pitch length on the temperature change. preferable. When it is difficult to suppress the temperature dependence of the display color with a single liquid crystal material, a plurality of chiral agents having different temperature dependences such as positive and negative temperature dependence of the display color may be used.

In the liquid crystal shutter according to the present invention, the polymer substance dispersed and contained in the liquid crystal layer may be disposed so that the cholesteric liquid crystal is most stabilized at its natural pitch length P ₀ . For example, by causing a polymerizable substance to coexist with the liquid crystal layer and causing the cholesteric liquid crystal to polymerize in a state having its natural pitch length P ₀ , the intermolecular force between the liquid crystal molecules in the state of polymerization and the polymer substance is large. It can be. The constituent material of such a polymeric substance is not particularly limited, and for example, a composition represented by the general formula R ₁ -S ₁ -MS ₂ -R ₂ may be used.

[0032]

Embedded image Further, it is preferable that the compatibility with the liquid crystal material to be mixed is good. From this point, a polymer of a polymerizable substance exhibiting liquid crystallinity by binding a mesogen site in the molecule may be used. As the mesogen site of the polymeric substance,
For example, phenyl, biphenyl, terphenyl,
Examples include a phenylcyclohexyl group, a biphenylcyclohexyl group, a phenyldicyclohexyl group, an azobenzene group, an azoxybenzene group, a benzylideneaniline group, a stilbene group, and a tolan group.

The polymerizable substance may be a polymerizable monomer, or an oligomer derived from the monomer, or a mixture of the oligomer and the monomer in terms of reactivity and viscosity. Then, a polymer may be obtained by using a polymer. From the viewpoint of easy polymerization control, it is more preferable to use a polymer of a material having photocurability. As the polymerizable monomer or oligomer, for example, a monoacrylic monomer or oligomer, a diacrylic monomer or an oligomer which is polymerized and cured by irradiation with ultraviolet light can be mentioned as a suitable material.

The hydrogen at the α-position and / or β-position of the vinyl group may be substituted with a phenyl group, an alkyl group, a halogen group, a cyano group, or the like. Examples of the polymerizable monomer serving as the material of the polymer substance include substances having the structural formulas shown in Table 1. Examples of commercially available and easily available products include, for example, Kayarad {DD}, Kayarad MAND, and Kayarad.
-220, Kayarad HX-620, Kayarad R-5
51, Kayarad R-712, Kayarad R-604,
Kayarad R-167 (Nippon Kayaku Co., Ltd.), Acryester BZ, Acryester ク リ, AcryesterΗ
P (all manufactured by Mitsubishi Rayon Co., Ltd.) and the like can also be used.

Further, when forming a polymeric substance to be disposed together with liquid crystal molecules in order to stabilize the helical pitch of the liquid crystal layer, a polymerization initiator may be used in order to promptly carry out polymerization. Any photopolymerization initiator may be used as long as it is suitable for the selected monomers and oligomers. Examples of commercially available photopolymerization initiators include Darocur 1173 (manufactured by Merck) and Darocur 11
16 (Merck), Irgacure 184 (Cib
a Geigy), Irgacure 651 (Ciba
Geigy), Irgacure 907 (Ciba
Geigy), Kayacure DETX (Nippon Kayaku), Kayacure EPA (Nippon Kayaku) and the like. The amount of the photopolymerization initiator to be added is preferably, for example, about 5% by weight or less based on the monomers and oligomers from the viewpoint of maintaining a high liquid crystal retention. Further, the polymerizable monomer or oligomer may contain a modifier such as a crosslinking agent, a surfactant, a polymerization accelerator, a chain transfer agent, or a photosensitizer, if necessary.

As a method for producing a liquid crystal layer containing a polymer substance in the liquid crystal shutter of the present invention, for example, as described above, the natural helical pitch length P
_{At 0} , the polymerizable substance may be polymerized.
At this time, it is preferable to carry out photopolymerization after sandwiching a mixture of a polymerizable monomer or oligomer and a liquid crystal material between substrates. At this time, by controlling the light irradiation intensity and light irradiation time, the medium is not in a light scattering state,
It can be in a transparent state. Further, by controlling the temperature of the medium during the polymerization, the structure of the medium can be more precisely controlled. The method of sandwiching the transparent medium between the substrates is not particularly limited, and may be performed by a method such as vacuum injection, suction injection, or application.

In the liquid crystal shutter according to the present invention, any type of electrode for applying a voltage to the liquid crystal layer may be used as long as an electric field in a direction parallel to the substrate (in-plane direction of the liquid crystal layer) can be applied. It may be used. As the light-transmitting electrode, for example, a thin film of ITO (indium tin oxide) can be used by being formed by a sputtering method or the like. For electrodes that do not require transparency, such as reflective electrodes, aluminum, nickel, copper, silver,
Various electrode materials such as gold and platinum can be used. Further, the electrodes may be formed on the substrate by a usual method such as vapor deposition, sputtering, or photolithography. Further, the electrodes may be provided only on one of the pair of substrates sandwiching the liquid crystal layer, or may be provided on both substrates. Arranging electrodes on both substrates can apply a more uniform electric field. If further uniformity of the electric field is desired, a columnar electrode may be arranged between the substrates sandwiching the liquid crystal layer. At this time, as described later, the columnar electrode may also have a function of a spacer for defining the size of the substrate gap.

The substrate constituting the liquid crystal shutter of the present invention, which sandwiches the liquid crystal layer, may be any substrate having sufficient strength, insulation and transparency.
Plastic, ceramic, or the like can be used.
Also, the thickness is not particularly limited as long as the strength is not impaired.

In the liquid crystal shutter of the present invention, an insulating thin film may be formed on the surface of the electrode for applying an electric field to the liquid crystal layer. The material of the insulating thin film is not particularly limited as long as it has no reactivity or solubility with respect to the liquid crystal material and is electrically insulating. Further, such an insulating thin film may be provided not only on the electrode surface but also on the entire surface of the substrate where the liquid crystal layer is sandwiched. Further, such an insulating film may be used as an alignment film.

As the constituent material of the insulating film, for example, an organic substance such as polyimide, polyamide, polyvinyl alcohol, polyacrylamide, cyclized rubber, novolak resin, polyester, polyurethane, acrylic resin, bisphenol resin or gelatin; Examples thereof include inorganic substances such as silicon nitride. The orientation film is formed by a method such as Langmuir-Blodgett method (L) in which a monomolecular film formed on a water surface is transferred onto an electrode substrate and laminated to form a thin film.
B), a vapor deposition method, or the like may be used, and a method suitable for the constituent material of the insulating film may be selected. The thickness of the insulating thin film is not particularly limited as long as voltage can be sufficiently applied to the liquid crystal layer. However, the thickness of the insulating thin film may be set as thin as possible without impairing the insulating property from the viewpoint of low voltage driving. preferable. In general, the alignment treatment for the insulating thin film may be performed substantially in parallel to the voltage application direction, and may be performed, for example, by rubbing, optical alignment, oblique deposition, or the like. In the present invention, the size of the gap between the substrates sandwiching the liquid crystal layer, in order to more accurately control the uniformity,
Various spacers may be used. As the spacer, for example, a spherical spacer or a rod-shaped spacer may be sprayed on the liquid crystal layer sandwiching surface of the substrate by an electrostatic spraying method or the like. In addition, when the substrates are combined, it is difficult to make the distribution density uniform because the spacers come close to each other, so that columnar insulators may be provided at regular intervals on the substrate. The spacer material to be sprayed on the substrate is not particularly limited as long as it is insulative and does not react or dissolve with the liquid crystal molecules to be used and is stably dispersed on the substrate.For example, divinyl benzene, polystyrene And inorganic oxides such as alumina and silica. It is preferable that the particle size distribution of the spacer used is as narrow as possible. As a method for forming the columnar bodies on the electrode substrate at regular intervals, the columns may be formed by a photolithography method or the like, or may be formed by printing or the like.
As the material thereof, a positive or negative photosensitive resin having no reactivity or solubility with respect to the liquid crystal material and electrically insulating can be used. For example, polyimide,
Polyamide, polyvinyl alcohol, polyacrylamide, cyclized rubber, novolak resin, polyester, polyurethane, acrylic resin, bisphenol resin or gelatin can be mentioned as a photosensitive resin,
Generally, a negative photosensitive polyimide is preferable.

As described above, in the liquid crystal shutter of the present invention, a plurality of liquid crystal layers each having two liquid crystal layers having the same helical orientation as a unit and a λ / 2 plate may be used in combination. As the λ / 2 plate to be used, it is preferable to use a retardation plate whose wavelength λ matches the center wavelength of the selective reflection of the cholesteric phase and has high transmittance.

As described above, in the liquid crystal shutter of the present invention, a plurality of liquid crystal layers having the same helical direction, a polarization conversion sheet, and a λ / 4 plate may be used in combination. The sheet for converting non-polarized light into right or left circularly polarized light may be, for example, a combination of a commercially available linearly polarized light conversion sheet and a λ / 4 plate, or red, green, and blue having the same helical orientation. May be used in combination with three cholesteric liquid crystal optical elements that selectively reflect light.

As the display means in the display device of the present invention, for example, a black and white fluorescent tube may be used. Red,
There is no particular limitation as long as it is a so-called black-and-white type having a mixed phosphor of green and blue. Further, a plurality of electron beam fluorescent tubes may be used in combination for a large screen display device. In the display device of the present invention, if there is a wavelength component that cannot be covered by the red, green, and blue selective reflection spectra of the liquid crystal shutter in the red, green, and blue emission spectra of the black-and-white fluorescent tubes, the color purity of the display screen is reduced. Will be. Therefore, in order to ensure color purity, it is preferable to make the selective reflection spectrum of the liquid crystal shutter correspond to the emission spectrum of the fluorescent tube. Alternatively, a wavelength component that cannot be covered by the selective reflection spectrum of the liquid crystal shutter in the blue emission spectrum may contain a dye having absorption. Further, a transparent substrate coated with a dye may be combined with a liquid crystal shutter.

In order to secure a wide viewing angle in the liquid crystal shutter and the display device of the present invention, means for making incident light to the liquid crystal shutter parallel and means for making light emitted from the liquid crystal shutter wide angle. May be combined.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

(Embodiment 1) Here, the basic structure and operation of the liquid crystal color shutter of the present invention will be described.
FIG. 1 is a diagram schematically showing an example of the configuration of the liquid crystal color shutter of the present invention. FIG. 1A shows a state where a driving voltage is not applied to the liquid crystal layer, and FIG. 1B shows a state where a driving voltage is applied to the liquid crystal layer.

This liquid crystal color shutter has a liquid crystal layer 13 exhibiting a cholesteric phase sandwiched between a first substrate 11 and a second substrate 12. In addition, a comb-shaped electrode 14 arranged to form an electric field in a direction parallel to a plane direction of the first substrate 11 and the second substrate 12 is provided. FIG. 2 is a view schematically showing an example of a pattern of the liquid crystal molecules of the comb-shaped electrode viewed from the helical axis direction. FIG. 2 is an enlarged view of a part of the electrode pattern in which the conductor layer 14a is arranged in an interdigital shape. Is shown. The voltage applying means 15 is applied to the comb-shaped electrode 14.
A driving voltage is applied to apply a horizontal electric field to the liquid crystal layer 14 to change the helical pitch of the liquid crystal molecules constituting the liquid crystal layer 13, thereby changing the wavelength of light transmitted through the liquid crystal layer 13 or selectively reflecting the liquid crystal layer 13. The wavelength of the light is controlled.

As shown in FIG. 1A, when no drive voltage is applied, the liquid crystal layer 13 has a helical pitch length P in a natural state.
_{It has} a planar structure of ₀ . At this time, assuming that the average refractive index of the liquid crystal is n, the liquid crystal layer 13 reflects light having a wavelength in the selective reflection region centered on the wavelength λ defined by λ = n × P ₀ . When the driving voltage of the liquid crystal layer 13 is applied, as shown in FIG. 1B, the helical pitch length of the liquid crystal molecules is extended to form a planar structure having a helical pitch length Pi, and the wavelength of the selectively reflected light shifts to the longer wavelength side. Therefore, by controlling the applied voltage, the selectively reflected light can be set to the three primary colors of additive color mixture, that is, red, green, and blue. For example, the helical pitch of the liquid crystal molecules corresponding to the driving voltage Vi is P
Since Pi changes according to Vi, the wavelength nxPi of the selectively reflected light at the helical pitch Pi is set to the three primary colors of the additive color mixture, that is, red, green, and blue. The wavelength of the selectively reflected light can be changed to red, green, and blue, so that the liquid crystal color shutter can be operated.

When the wavelength of the reflected light (for example, three primary colors) is switched to form a liquid crystal color shutter, the selectively reflected light can be used as it is. On the other hand, for example, when the three primary colors of the transmitted light are switched and used as in the color image display device of the present invention, the left and right circularly polarized light components of two of the three primary colors are incident on the liquid crystal layer 13 as selectively reflected light. Must be removed from light.

(Embodiment 2) In the liquid crystal color shutter of the present invention, the arrangement of the electrodes for forming an electric field in the liquid crystal layer is such that a more uniform electric field is applied to the liquid crystal layer in the vertical direction of the substrate holding the liquid crystal layer 13 therebetween. Therefore, instead of the comb-shaped electrode as shown in FIG. 2, for example, a columnar electrode 16 as shown in FIG.
May be used. FIG. 3 is a diagram schematically showing another example of the configuration of the liquid crystal color shutter of the present invention. FIG. 3A shows a state in which no drive voltage is applied to the liquid crystal layer.
FIG. 3B shows a state where a driving voltage is applied to the liquid crystal layer. When the comb-shaped electrode 14 is used, it is difficult to obtain a uniform electric field in the normal direction of the substrate.
In the region 3 far from the electrode, the strength of the electric field formed is smaller than that in the region close to the electrode, such as the surface of the electrode. For this reason, the helical pitch length of the liquid crystal molecules is shorter than that near the electrodes, and the spectrum of the selectively reflected light is broadened to the shorter wavelength side. On the other hand, when the columnar electrode 16 is used, a uniform electric field can be formed in the normal direction of the substrate, so that the spectrum of the selectively reflected light does not become broad. However, the reflection / transmission of the emission spectrum of the fluorescent tube may be efficiently controlled by utilizing the phenomenon that the spectrum of the selective reflection light becomes broad as described later.

(Embodiment 3) Next, the operation of the liquid crystal color shutter of the present invention will be schematically described. In the liquid crystal color shutter of the present invention, the wavelength of the transmitted light or the selectively reflected light is controlled by transitioning between planar structures having different helical pitch lengths. Of these, the change to a structure having a shorter helical pitch length is performed by an electric field. This is a relaxation process that cannot be performed, and it is this process that is rate-determining for realizing a high-speed response.

In the liquid crystal color shutter of the present invention, the above-mentioned two constitutions, namely, a constitution in which the relaxation process is accelerated by stabilizing the liquid crystal molecules by an intermolecular force with the polymeric substance, or a helical pitch in a natural state P
_A high-speed electro-optical response is realized by adopting a configuration in which the relaxation rate is increased by transitioning a plurality of states larger than ₀ .

[0053] Figure 4 so that the liquid crystal molecules constituting the cholesteric phase is stabilized in a state of natural helical pitch length [rho _0, an example which is disposed between the substrates of polymeric material 17 with the liquid crystal layer 13 schematically FIG.

In order for the polymer obtained by polymerizing the polymerizable substance to be dispersed and contained in the liquid crystal layer, for example, the polymerizable substance is added to the first material together with the material constituting the liquid crystal layer 13 such as a liquid crystal material.
Between the first substrate 11 and the second substrate 12. At this time, the gap between the substrates and the length of the helical pitch are selected so that the liquid crystal layer 13 is arranged in a planar manner. As the polymerizable substance, when a material having high compatibility with the liquid crystal material, for example, a polymerizable substance having liquid crystallinity is used, a planar structure in which the polymerizable polymer substance 17 is dispersed at a micro level in the liquid crystal material or the chiral agent is obtained. be able to. At this time,
For example, as the polymerizing a polymerizable material, such as by light irradiation illustrated in FIG. 4 (a), the polymeric material 17 formed by the polymerization, while planar array of liquid crystal molecules 13a in a natural helical pitch length [rho ₀ Stabilize. This is because the interaction intermolecular force or the like of the liquid crystal molecules 13a and the polymer material 17 is larger in the natural helical pitch length [rho _0.

When the polymer is provided as described above, the elastic energy in the state of P ₀ of the liquid crystal molecules 13 a constituting the liquid crystal layer 13 is reduced, and the liquid crystal layer 13 is further stabilized. Therefore, it is possible to increase the energy difference from the planar structure (Ρ ₀ <Ρ i) in which the helical pitch length Pi is increased by the voltage application. Spiral pitch length て i (Ρ ₀ <Ρi) from the voltage applied state when the voltage is turned off.
The relaxation time to the _zero state is inversely proportional to the energy difference between the two states with different helical pitch lengths. Therefore, the transition speed from the state where the helical pitch of the liquid crystal molecules is long to the state where the helical pitch is short is increased, and the operation speed of the liquid crystal color shutter can be increased.

[0056] (Embodiment 4) Next, description will be given of a liquid crystal color shutter of the present invention where the configuration to speed up the relaxation rate by transitioning a large plurality of states than the helical pitch P ₀ of the natural state.

FIG. 5 is a diagram for explaining a liquid crystal color shutter according to the present invention which transits a plurality of states larger than the helical pitch P ₀ in the natural state. Figure 5 (a) shows how the cells when the helical pitch Pi = P ₀ of the liquid crystal molecules,
Figure 5 (b) is state of the cells when the helical pitch Pi = P ₁ of the liquid crystal molecules, FIG. 5 (c) each schematically show the state of the cells when the helical pitch Pi = P ₂ of the liquid crystal molecules ing.

[0058] In the liquid crystal color shutter of the present invention, a natural helical pitch a large plurality of states than the liquid crystal molecules 13a (e.g. Pi = like _{P 1, Pi = P 2)} , the wavelength of the light transmitted through or reflection liquid crystal layer To correspond to. For example,
B at the time of the helical pitch P ₁ (blue), the helical pitch P ₂
G a (green), and although not shown may be as to correspond to R (red) when the helical pitch P ₃ at. The helical pitch Pi of the liquid crystal molecules is P _1, P _2,
By applying a drive voltage to the liquid crystal layer so as to reach P ₃ , the wavelength of light transmitted or selectively reflected by the liquid crystal layer can be controlled.

As described above, in the liquid crystal color shutter of the present invention, a plurality of states (for example, the helical pitch P ₁ , the helical pitch P ₁ , the helical pitch P ₁ , the helical pitch larger than the helical pitch P ₀ in the natural state of the cholesteric liquid crystal or the chiral nematic liquid crystal). P ₂ , between helical pitch P ₃ , P
_The transition of ₀ <P ₁ <P ₂ <P ₃ controls the wavelengths of the transmitted light and the reflected light. For example from a large helical pitch P ₂ than the helical pitch P ₀ of the natural state, the relaxation process of the helical pitch P _1, also for example from the helical pitch P _3, to speed the relaxation process of the helical pitch P _2, required for the state transition Time can be shortened.

Energy E at spiral pitch length Ρi
i can be expressed as: Εi = ｛K ₂₂ (2π / Ρ ₀ -2π / Ρi) ² } / 2. Therefore, for example, the helical pitch length Pi = Ρ
_{1, Pi = Ρ 2 (Ρ} 0 ≦ P 1 <Ρ 2) respectively lambda ₁ selective reflection wavelength in, lambda _2, also the average refractive index of the liquid crystal n
Then, the energy difference ΔE (= E ₂ −E ₁ ) between the two planar structures having different helical pitch lengths is as follows: ΔE = 2π ² K ₂₂ Ρ (1 / Ρ ₁ ) − (1 / Ρ ₂ )｝ × {(2 / P ₀ ) − (1 / P ₁ ) − (1 / P ₂ )} = 2π ² K ₂₂ n ² {(1 / λ ₁ ) − (1 / λ ₂ )} × {(2 / λ) − (1 / λ ₁ ) − (1 / λ ₂ )｝. Therefore, when configuring the liquid crystal color shutter of the present invention, the liquid crystal material and the chiral agent may be selected and the mixing ratio may be determined so that the natural helical pitch length 液晶₀ of the liquid crystal molecules takes a small value. . In this case, since the helical pitch length Pa at the shortest wavelength in the selective reflection area set by the cell of one liquid crystal color shutter is longer than the natural helical pitch length P ₀ , a voltage (bias voltage) is always applied. I just need. The lower limit of the natural helical pitch length P ₀ may be determined in consideration of the relationship between voltage and helical pitch length (Vi−Pi). In the liquid crystal color shutter of the present invention having such a configuration, the state of the helical pitch P ₀ is, for example, B
The cells of the liquid crystal color shutter in the state of the helical pitch P ₀ do not correspond to wavelengths such as (blue), G (green), and R (red), and correspond to the shorter wavelength side (violet outer side) than blue. become. In the liquid crystal color shutter of the present invention,
For example, by configuring the cell so that the wavelength of the selectively reflected light in the state where no voltage is applied shifts to the violet side outside the visible region, the wavelength control of the transmitted light or the selectively reflected light can be performed with more elastic energy than in the natural state. This can be performed by transitioning between a plurality of large states.

By adopting such a configuration, in the liquid crystal color shutter of the present invention, the wavelength control of the transmitted light or the selectively reflected light of the liquid crystal layer corresponding to the helical pitch of the liquid crystal molecules is accelerated to, for example, about 1 ms or less. be able to. Note that this method may be used in combination with the above-described method of containing a polymer substance.

(Embodiment 5) Next, a liquid crystal color shutter of the present invention including a plurality of liquid crystal layers having different helical directions of a cholesteric phase will be described.

First, a polymer substance is dispersed and Pi =
A case where the state of P ₀ is stabilized will be described. FIG.
FIG. 3 is a view schematically showing an example of the configuration of a liquid crystal color shutter of the present invention. This liquid crystal color shutter is formed by stacking a plurality of cells having different helical orientations of a cholesteric liquid crystal layer in order to control the wavelength of transmitted light. Here, cell 21 and cell 2 selectively reflect blue when no voltage is applied.
2, and an example in which a liquid crystal color shutter is composed of four cells, a cell 23 and a cell 24, which selectively reflects green when no voltage is applied. The cells 21 and 23 have a right-handed spiral orientation and reflect the right-handed circularly polarized light component.
The helical direction is left-handed and reflects the left-handed circularly polarized light component. When a voltage is applied, the applied voltage is controlled so that the cells 21 and 22 selectively reflect green, and the cells 23 and 24 selectively reflect red. Here, the cells 21, 22, 23, and 24 have the same configuration as the liquid crystal color shutter of the present invention as described above.

FIG. 7 is a diagram showing an example of the selective reflection spectrum of the liquid crystal color shutter illustrated in FIG. Cell 21
The selectively reflected light spectrum of the set of the cell 22 and the cell 22 has a profile 31 when no voltage is applied and a profile 32 when a voltage is applied.
Thus, the selectively reflected light spectrum of the set of the cell 23 and the cell 24 becomes the profile 32 when no voltage is applied and the profile 33 when the voltage is applied. These two sets of cells 21, 22,
One of the three primary colors of additive color mixture can be selected and displayed by a combination of application of voltage 23 and application of voltage 24.

FIG. 8 shows a set of a cell 21 and a cell 22, and a cell 23.
FIG. 9 is a diagram for explaining the color of transmitted light corresponding to a set of a cell and a cell 24 when voltage is applied and when voltage is not applied. FIG. 9 is a diagram showing transmitted light spectra corresponding to a set of cells constituting the liquid crystal color shutter according to the present invention when a voltage is applied and when no voltage is applied, and FIGS. 9 (a), 9 (b), and 9 ( c) is cell 2
1 shows a transmitted light spectrum corresponding to a pair of cell 22 and a pair of cell 23 and cell 24 when voltage is applied and when voltage is not applied. Note that the arrangement order of the cells is not particularly limited. Furthermore, for a total of four combinations when no voltage is applied / applied to each of the two sets of cells,
Regarding which color of the transmitted light is made to correspond, the helical pitch length Pi of the liquid crystal molecules and the applied voltage Ei are set so that at least one of the three primary colors of red, green and blue is included in each of the four combinations.
Is not particularly limited as long as is controlled. Next, a case where the transmitted light is controlled by changing a plurality of states in which the helical pitch is larger than P ₀ will be described. Cells In this case, the helical pitch selectively reflecting green cell 21 and the cell 22, also when the first voltage E ₁ is applied selectively reflecting blue upon larger such first voltage E ₁ is applied than P ₀ An example in which a liquid crystal color shutter is constituted by four cells 23 and 24 will be described. Cell 21, cell 2
Cell 3 has a right-handed helix and reflects the right-handed circularly polarized light component.
2 and the cell 24 have a left-handed helical orientation and reflect a left-handed circularly polarized light component. The cell 21 and the cell 22 at the time of the second voltage E ₂ is applied
Selectively reflects green, and when the second voltage E _{2 is} applied, the cell 23
And the cell 24 controls the applied voltage so as to selectively reflect red. In this case, the set of selective reflection light spectrum of the cell 21 and the cell 22, when the first voltage E ₁ applied profile 31, next to the profile 32 at the time of the second voltage E ₂ is applied, the cell 23 and the cell 24 pairs the selective reflection light spectrum, when a first voltage E ₁ applied profile 32, when the second voltage E ₂ is applied is a profile 33. By controlling the applied voltages of the two sets of cells 21, 22, 23, and 24, one of the three primary colors of additive color mixture can be selected and displayed. At this time, according to the present invention, it is possible to shorten the time of the state transition from the selection state of one color to the selection state of another color, and therefore to increase the response speed of the liquid crystal color shutter and improve the display quality. Can be.

(Embodiment 6) Next, an example in which the liquid crystal color shutter of the present invention is constituted by using three sets of cells having different helical orientations of the cholesteric phase will be described. FIG. 10 is a diagram schematically showing an example of the configuration of the liquid crystal color shutter of the present invention. Also in this case, all the cells constituting the liquid crystal color shutter adopt the same configuration as the above-described liquid crystal color shutter of the present invention.

First, a polymer substance is dispersed and Pi =
A case where the state of P ₀ is stabilized will be described. In this case, the liquid crystal color shutter is composed of cells 41 and 42,
The cells 43 and 44 and the cells 45 and 46 selectively reflect one of the three primary colors of additive mixture when no voltage is applied, and the wavelength region of the selectively reflected light corresponds to the infrared region side when a voltage is applied. Is set to

In this example, cells 41, 43, 45
Indicates that the helical direction of the cholesteric phase is set to clockwise,
In the cells 42, 44, and 46, the helical orientation of the cholesteric phase is set to the left-handed direction. When no voltage is applied, the cells 41 and 42 selectively reflect red light, the cells 43 and 44 selectively reflect green light, and the cells 45 and 46 select blue light. It is set so as to be reflected, and the wavelength region of the selectively reflected light of all cells is set to be in the infrared region when a voltage is applied. By adopting such a configuration, of the three sets of cells,
By applying a voltage to one set and not applying a voltage to the other two sets, a state in which the transmitted light is one of the three primary colors can be selected. Also in this case, the arrangement order of the cells is not particularly limited.

Next, a case where the transmitted light is controlled by making a transition between a plurality of states in which the helical pitch is larger than P ₀ will be described. In this case, liquid crystal color shutters, cell 41 and cell 42, cell 43 and cell 44, cell 45 and cell 46, each of the three primary colors of additive color mixture at the time of the first voltage E ₁ is applied that corresponds to Pi = P ₁ It is set so that one color is selectively reflected, and when the second voltage E ₂ corresponding to Pi = P ₂ is applied, the wavelength region of the selectively reflected light corresponds to the infrared region side.

In this example, cells 41, 43, 45
Indicates that the helical direction of the cholesteric phase is set to clockwise,
In the cells 42, 44, and 46, the helical orientation of the cholesteric phase is set to the left-handed direction. When the first voltage E _{1 is} applied, the cells 41 and 42 selectively reflect red light, the cells 43 and 44 selectively reflect green light, and the cells 45 and 46 are connected to each other. is configured to selectively reflects blue light, the wavelength region of selective reflection light of the second voltage E ₂ voltage applied sometimes to the all cells are set to be in the infrared region. By adopting such a configuration, by transmitting the second voltage to one of the three sets of cells and applying the first voltage to the remaining two sets, the transmitted light becomes 3
A state in which one of the primary colors is obtained can be selected.
Also in this case, the arrangement order of the cells is not particularly limited.

(Embodiment 7) Next, an example in which a liquid crystal color shutter of the present invention is constituted by combining a plurality of liquid crystal layers having the same helical orientation of the cholesteric phase with a λ / 2 plate will be described. FIG. 11 is a view schematically showing an example of the configuration of the liquid crystal color shutter of the present invention. In this liquid crystal color shutter, two cells 51 and 52 and a cell 53 and a cell 54 are simultaneously controlled to apply or not apply a voltage or to control the first voltage E ₁ and the second voltage E _2. On the other hand, λ / 2 retardation plates 55 and 56 are provided. Here, the cells 51 and 52 and the cell 5
The cell 3 and the cell 54 have the same configuration, and may be configured similarly to the liquid crystal color shutter of the present invention as described above.

Two identical cells and λ /
The pair composed of two plates corresponds to, for example, a pair composed of one cell each having a right-handed and left-handed spiral orientation in FIG.
The λ / 2 plate to be used may be selected in consideration of the wavelength of the selectively reflected light at the time of driving. Two sets of placement order,
The helix orientation is not particularly limited. In the present method using a λ / 2 plate, two identical cells can be used. Therefore, in comparison with the case where one cell is used for each of the right-handed and left-handed helical orientations, selection of a chiral agent, etc. This increases the degree of freedom in material selection and is advantageous in terms of manufacturing costs. This is because, in order to produce cells having the same natural helical pitch length and the same temperature characteristics for right-handed and left-handed windings, it is a general method to use a pair of dextrorotatory and levorotatory optical isomers. This is because one of the optically active optical isomers is usually more difficult to obtain than the other.

(Embodiment 8) FIG. 12 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention. This example shows a configuration in which one λ / 2 plate is used for the entire liquid crystal color shutter. In this liquid crystal color shutter, cells 61a, 61b, and 62
a and the cell 62b may be arranged one by one on each side of the λ / 2 plate 63, and the arrangement order of the cells is not particularly limited as long as this is satisfied.

FIGS. 11 and 12 show the case where two sets of cells are used as illustrated in FIG. 6, but three sets of cells as illustrated in FIG. 10 may be used.

(Embodiment 9) Next, the present invention comprises a polarization conversion sheet for converting non-polarized light into right circularly polarized light or left circularly polarized light, and a cell having the converted circularly polarized light direction and the same helical direction as the cholesteric phase. The liquid crystal color shutter will be described.

FIG. 13 is a diagram schematically showing an example of the configuration of the liquid crystal color shutter of the present invention. In this case, since the light whose wavelength is to be controlled by the liquid crystal color shutter is converted into one of the circularly polarized light components at the stage of entering the cell, the liquid crystal color shutter requires a smaller number of cells than the configuration described above. Can be configured. When a right-handed cholesteric phase is used, a polarization conversion sheet that converts non-polarized light into right-handed circularly polarized light is used.When a left-handed cholesteric phase is used, a polarization conversion sheet that converts left-handed cholesteric phase is used. I just need. As such a polarization conversion sheet, a polarization conversion sheet composed of an absorption type linear polarizing plate and a λ / 4 plate, or a non-polarized light by multiple reflection with a light source side in order to realize higher transmittance. A polarization conversion sheet that converts all the incident light into one circularly polarized light may be used.

Now, an example in which a polarization conversion sheet 73 in which all the transmitted light is right-handed circularly polarized light is used will be described. When all of the light transmitted through the polarization conversion sheet 73 becomes right-handed circularly polarized light, the two cells 71 and 72 both use right-handed cells with spiral orientations. Here, cell 71, cell 7
Reference numeral 2 corresponds to the cells 21 and 23 of the liquid crystal color shutter of the present invention illustrated in FIG. 6, respectively.

The liquid crystal color shutter having the structure shown in FIG. 13 corresponds to the liquid crystal color shutter of the present invention shown in FIG. 6. For example, the liquid crystal color shutter of the present invention shown in FIG. A corresponding cell configuration may be adopted. The cell arrangement order is not particularly limited.

(Embodiment 10) Here, a color image display device of the present invention will be described. The color image display device of the present invention includes the above-described liquid crystal color shutter of the present invention and one or more monochrome fluorescent tubes, and performs color image display.

FIG. 14 is a diagram schematically showing the configuration of a color image display device according to the present invention. A display device 80 in which a plurality of monochrome fluorescent tubes 81 are arranged vertically and horizontally to form an integrated display screen.
And four cells 21, 2 as exemplified in FIG.
An example is shown in which the liquid crystal color shutter 20 of the present invention composed of 2, 23, and 24 is combined. For the white light emitted from the display screen of the display device 80 and having a gradation corresponding to the color information, the color selection of the transmitted light is performed by the liquid crystal color shutter 20 in accordance with the color information, and among the three primary colors of the additive color mixture, One color is displayed. In this example, a synchronization circuit 82 is used to synchronize the display timing of the image having the gradation corresponding to the color information on the display screen with the switching timing of the liquid crystal color shutter for coloring the image. The synchronizing circuit 82 allows the raster generator 83 and the control circuit 84
Of the liquid crystal color shutter 20
And the display of a black-and-white (grayscale) image having gradation information corresponding to the display color can be performed in synchronization with each other. In the liquid crystal color shutter of the present invention that constitutes the display device of the present invention, by employing the above-described configuration, the switching of the transmitted light or the selectively reflected light is performed for about 1 ms.
Since the switching can be performed at a high speed equal to or less than the order, flicker can be reduced and a color image with high display quality can be displayed. The liquid crystal color shutter used in combination with the display device is not limited to the configuration illustrated in FIG.
For example, various types of liquid crystal color shutters of the present invention as exemplified in FIGS. 10, 11, 12, and 13 can be used.

(Embodiment 11) In the color display device of the present invention having a structure as exemplified in FIG. 10, for example, the emission spectrum of the fluorescent tube constituting the display device 80 must be kept high to ensure high color purity. It is preferable that the selective reflection spectrum of the liquid crystal color shutter be set to overlap.

FIG. 15 is a diagram for explaining the relationship between the spectrum of light emitted from the display screen of the display device and the selective reflection spectrum of the liquid crystal color shutter. In FIG. 15, an example of the emission spectrum of the black-and-white fluorescent tube is shown as a profile 91. Here, of the emission spectrum of the fluorescent tube, light in a wavelength region that is not covered by the selective reflection spectrum of the liquid crystal layer of the liquid crystal color shutter always transmits through the liquid crystal color shutter, so that it is difficult to ensure high color purity. is there.

By setting the natural helical pitch length, the selective reflection wavelength width, and the applied voltage so that the red, green, and blue selective reflection spectra at the liquid crystal color shutter are 94, 93, and 92, respectively, High color purity can be ensured. If there is an unnecessary wavelength component, such as an emission spectrum in a wavelength range that cannot be covered by the selective reflection spectrum, a dye that absorbs light in that wavelength range should be provided in the liquid crystal layer or the like to absorb it. You may. In this case, the dye may be mixed with the liquid crystal layer or applied to the substrate. Further, a pigment coated or sandwiched on another transparent sheet or the like may be used.

In the above description, color switching of transmitted light has been mainly described, but the present invention may be applied to color switching of reflected light.

(Embodiment 12) A more specific embodiment of the present invention will be described below.

A liquid crystal color shutter of the present invention having a structure in which a polymer substance coexists in the liquid crystal layer to stabilize the ground state of liquid crystal molecules was manufactured, and its characteristics were evaluated.

The first substrate 11 made of glass (having a thickness of 0.
7 mm), a comb-shaped electrode 14 made of MoW and having an electrode width of about 10 μm and an electrode interval of about 10 μm was formed by an ordinary method.
Next, polyimide (AL-1051: Nippon Synthetic Rubber Co., Ltd.)
Was cast to a thickness of about 70 nm on the surface on which the comb-shaped electrode 14 was formed by a spinner to form an insulating film. Similarly, another second substrate 1 made of a light-transmitting insulating material such as glass.
An insulating film was also formed on the liquid crystal sandwiching surface 2 (thickness: 0.7 mm).

Next, rubbing was performed on both insulating films by an ordinary method. At this time, the rubbing direction was set so as to be substantially parallel to the direction of the electric field when a voltage was applied.

Next, an epoxy adhesive for bonding is applied to a predetermined position on the surface of the insulating film of the second substrate 12 on which the comb-shaped electrodes 14 are not disposed, and the comb-shaped electrodes 14 are disposed. A resin spacer ball having a diameter of about 5 μm was sprayed on the surface of the insulating film of the first substrate 11 by electrostatic spraying or the like.

Thereafter, the two substrates were bonded together so that the insulating films faced each other, and the periphery was sealed. Liquid crystal layer 13 sandwiched between first substrate 11 and second substrate 12
Nematic liquid crystal (E48: manufactured by Erck) 5
0 wt% and chiral agent (CB15: Merck) 5
0 wt% was mixed. Next, 95% by weight of this liquid crystal mixture, 5% by weight of polymerizable monomer-1,4-di (4- (6- (acryloyloxy) hexyloxy) benzoyloxy) -2-methylbenzene, and a polymerization initiator (Irgacure 651: Ciba) A mixture obtained by adding about 0.5 wt% of a polymerizable monomer (manufactured by Geigy Corporation) to a polymerizable monomer was injected by a standard method, and the injection portion was also sealed to produce a liquid crystal color shutter.

In this state, when blue selective reflection light by the cholesteric phase planar structure was measured, it was confirmed that the central wavelength was about 450 nm. The cell was irradiated with ultraviolet light using a high-pressure mercury lamp to polymerize the polymerizable monomer. The light irradiation intensity in this step is about 10
0 mW / cm ² , the wavelength was about 365 nm, and the irradiation time was about 1 minute. The selective reflection color of the liquid crystal layer sealed in the cell hardly changed before and after the irradiation of ultraviolet rays, and this was designated as a cell (right-handed) 21.

Next, an optical isomer with a chiral agent (CB15: manufactured by Merck) was used as a chiral agent, and
A cell 22 (left-handed) was produced in the same manner as in Example 1 and blue selective reflection (center wavelength: 450 nm) was confirmed.

Further, a nematic liquid crystal (E48: Mer)
ck15) and a chiral agent (CB15: Mer)
Cell 23 (right-handed) was prepared in the same manner as the cell 21 except that 41 wt% (manufactured by ck) was mixed, and green selectively reflected light (center wavelength: 550 nm) was confirmed.

Next, a nematic liquid crystal (E48: Merck)
59% by weight, chiral agent (CB15: Merck)
Cell (left-handed) 24 was prepared in the same manner as in Cell 21, except that 41 wt% of the optical isomer was manufactured, and green selectively reflected light (center wavelength: 550 nm) was confirmed.

The cells 21, 22, 2
The liquid crystal color shutter of the present invention was manufactured by laminating 3 and 24 in order.

The driving voltages of the cells 21 and 22 are set so that the selective reflection light becomes green when a voltage is applied, and the cells 23 and 24 are set such that the selection reflection light becomes red when a voltage is applied. When no voltage is applied to all the cells 21, 22, 23 and 24, the transmitted light of the liquid crystal color shutter becomes red, and when a driving voltage is applied only to the cells 23 and 24, the liquid crystal color shutter is turned off. Set the transmitted light of the liquid crystal color shutter to be blue when voltage is applied to all cells so that the transmitted light becomes green, and select one of the three primary colors of the additive color mixture as the transmitted light. I confirmed that I can do it.

The operation speed at the time of color switching of the liquid crystal color shutter of the present invention thus configured was measured. The response time was 0.6 ms from no voltage application to application and 0.9 ms from voltage application to non-application, and high-speed color switching of 1 ms or less could be performed. For comparison, a liquid crystal color shutter similar to the conventional one in which no polymer was contained in the liquid crystal layer was prepared, and the response time required for color switching was measured. 6 ms, and 1.9 ms when no voltage was applied. When a field-sequential color display device such as that shown in FIG. 14, for example, is manufactured using a conventional liquid crystal color shutter, a problem of color mixing or color flicker occurs.

As described above, in the liquid crystal color shutter of the present invention, the time required for changing the length of the helical pitch of the liquid crystal molecules constituting the liquid crystal layer exhibiting a cholesteric phase, in particular, a transition from a long helical pitch to a short state. By shortening the time, a high-speed electro-optical response can be realized. Further, in the display device of the present invention, by employing a liquid crystal color shutter that operates at high speed, color flicker can be significantly reduced, and display quality can be improved.

(Embodiment 13) A liquid crystal color shutter of the present invention having a configuration in which a plurality of states in which the elastic energy of liquid crystal molecules is larger is changed was manufactured, and its characteristics were evaluated.

First, as in the twelfth embodiment, the first substrate and the second substrate were arranged to face each other and the periphery was sealed.

Next, a nematic liquid crystal (E48: Merc)
k company) 44% by weight and a chiral agent (CB15: Merc)
A liquid crystal composition composed of 56 wt% (manufactured by K Company) was injected by a conventional method to obtain a cell 21 (right-handed). Further, 44 wt% of a nematic liquid crystal (E48: manufactured by Merck), 56 wt% of an optical isomer of CB15, and a nematic liquid crystal (E48: Merck) were used.
ck) (51 wt%) (CB15: Merck)
A cell in which 49 wt%, 51 wt% of a nematic liquid crystal (E48: manufactured by Merck) and 49 wt% of an optical isomer of CB15 were injected between the substrates as a liquid crystal composition was used as a cell 22 (left-handed), a cell 23 (right-handed), respectively. It was produced as a cell 24 (left-handed).

When no voltage is applied to the cell (Pi =
The central wavelength of the selectively reflected light at P ₀ ) is 375 nm for the cells 21 and 22, and 460 nm for the cells 23 and 24.
Met. The cells 21, 22, 23, and 24 were sequentially stacked to produce a liquid crystal color shutter having the same configuration as that of FIG.

When the first voltage is applied to each cell constituting such a liquid crystal color shutter, the selectively reflected light from the cells 21 and 22 becomes blue (the center wavelength is 450 nm).
m) The drive voltage was set so that the selectively reflected light from the cells 23 and 24 became green (550 nm in center wavelength). Also,
When a second voltage higher than the first voltage is applied,
The selective reflection light of the cells 21 and 22 is green (the center wavelength is 55
0 nm), and the drive voltage was controlled so that the selectively reflected light from the cells 23 and 24 became red (center wavelength: 650 nm).

As described above, by controlling the voltage applied to the liquid crystal layer constituting each cell, the wavelength of light transmitted through the liquid crystal color shutter can be selected from red, green and blue. . Further, the response time required for the transition between the selected states of the respective colors is 0.6 ms, 0 ms, respectively, when the first voltage is applied to the second voltage, and when the second voltage is applied to the first voltage. .9 ms, and 1
High-speed color switching in ms or less could be performed.

As described above, in the liquid crystal color shutter of the present invention, a plurality of states (for example, the helical pitch P _{1 and the} helical pitch P _{2) having a} helical pitch longer than the helical pitch P ₀ in the natural state of the cholesteric liquid crystal or the chiral nematic liquid crystal. The transition of P ₀ <P ₁ <P ₂ ) makes it possible to control the wavelengths of the transmitted light and the reflected light at high speed.

As in the case of the twelfth embodiment, when the above-mentioned liquid crystal color shutter constitutes a color image display device of the present invention as exemplified in FIG. 14, for example, a bright image with little color flicker and high display quality can be displayed on a large screen. Could be displayed.

(Embodiment 14) A liquid crystal color shutter of the present invention having a structure in which a polymer substance coexists in a liquid crystal layer to stabilize the ground state of liquid crystal molecules was manufactured, and its characteristics were evaluated. Here, an example in which a liquid crystal color shutter of the present invention as illustrated in FIG. 10 is manufactured using three sets of liquid crystal cells having different helical directions will be described.

The cells 21 and 22 manufactured in Embodiment 12
Similarly to 23 and 24, the cells 41, 42, 43 and 44 are produced, and the cell 45 (right-handed) whose selective reflection light is red (center wavelength 650 nm) when no voltage is applied.
And a cell 46 (left-handed).

As a liquid crystal mixture before adding a polymerizable monomer, a cell 45 is a nematic liquid crystal (E48: Merck).
66% by weight and a chiral agent (CB15: Merck)
The cell 46 is made of a nematic liquid crystal (E4
8: Merck) and 66 wt% of CB15 optical isomer. The cell 41 thus manufactured,
42, 43, 44, 45, and 46 are sequentially stacked and arranged,
A liquid crystal color shutter of the present invention was produced. Note that, in order to prevent reflection and scattering of the gap between the stacked cells, the cells may be stacked via an oil matching the refractive index of the liquid crystal layer.

All the cells 41, 42, 43, 44, 4
In 5 and 46, the drive voltage was controlled such that the wavelength of the selectively reflected light upon application of the voltage was in the infrared region. By applying a voltage to any one of the three sets of cells, cell 41 and cell 42, cell 43 and cell 44, and cell 45 and cell 46, to the liquid crystal color shutter of the present invention thus configured. The color of the transmitted light could be selected from three primary colors of red, green and blue. When the operation speed was measured, it was exactly the same as that in the twelfth embodiment, and color switching could be performed at a high speed of 1 ms or less.

Further, as in the twelfth embodiment, when the above-mentioned liquid crystal color shutter constitutes a color image display device of the present invention as exemplified in FIG. 14, for example, a bright, high-quality image with little color flicker can be obtained. Could be displayed on the screen.

(Embodiment 15) Next, an example in which two sets of four cells having the same helical orientation and a λ / 2 plate are combined to produce a liquid crystal color shutter of the present invention as shown in FIG. 12, for example, will be described. I do.

Cell 21 and Cell 2 manufactured in Embodiment 12
Two cells 61 and 62 each having the same configuration as that of No. 3 were prepared. Then, the cells 61 and 62 having the same configuration
Cell 61, cell 62, λ / 2 plate, cell 61, cell 6
Each cell and a λ / 2 plate were arranged in the order of 2 to produce a liquid crystal color shutter.

The operation speed at the time of color switching of the liquid crystal color shutter of the present invention thus configured was measured. The response time was 0.6 ms from no voltage application to application and 0.9 ms from voltage application to non-application, and high-speed color switching of 1 ms or less could be performed.

As described above, in the liquid crystal color shutter of the present invention, the time required for changing the length of the helical pitch of the liquid crystal molecules constituting the liquid crystal layer exhibiting a cholesteric phase, in particular, transition from a long helical pitch to a short state. By shortening the time, a high-speed electro-optical response can be realized. Further, in the display device of the present invention, by employing a liquid crystal color shutter that operates at high speed, color flicker can be significantly reduced, and display quality can be improved.

[0116] (Embodiment 16) The polymeric material allowed to coexist in the liquid crystal layer, disposed on the display screen of the display device LCD color shutter of the present invention the structure for stabilizing the state of the helical pitch P ₀ of the liquid crystal molecules Then, its characteristics were evaluated. Here, a liquid crystal color shutter constructed using two sets of liquid crystal cells having different spiral orientations as illustrated in FIG.
The color image display device was constructed by disposing it on the display device 80 as illustrated in FIG.

The switching of red, green and blue colors of the liquid crystal color shutter is synchronized with the image displayed on the black and white fluorescent tube for 1 ms.
When the display was performed in the following manner (for example, 0.8 ms), color display with high display quality without color flicker could be performed. Further, since a color polarizing plate was not used, the transmittance of the light emitted from the display device to the liquid crystal color shutter could be greatly improved, and a bright and high-contrast display could be performed.

(Embodiment 17) Next, a color image display device according to the present invention having a configuration in which the liquid crystal color shutter according to the present invention and a display device in which a plurality of states in which the elastic energy of the liquid crystal molecules is larger transitions is combined. It was fabricated and its characteristics were evaluated.

A color display device was manufactured using the liquid crystal color shutter manufactured in the thirteenth embodiment and a plurality of black and white fluorescent tubes juxtaposed vertically and horizontally. 1m by synchronizing the switching of red, green and blue colors of the liquid crystal color shutter with the image displayed on the black and white fluorescent tube
s or less (for example, 0.9 ms), high-quality color display without color flicker could be performed. Further, in the liquid crystal color shutter and the color image display device of the present invention, since no color polarizing plate is used,
The transmittance of the light emitted from the display device to the liquid crystal color shutter was significantly improved, and a bright and high-contrast display was performed.

(Embodiment 18) Next, a color image display device of the present invention is manufactured using the liquid crystal color shutter (two sets of cells, four sheets) of the present invention constituted by using a polarization conversion sheet and a gray scale display device. Then, its characteristics were evaluated.

The liquid crystal color shutter was obtained by arranging the cell 21 (right-handed), the cell 23 (right-handed), and the circularly polarized light conversion sheet produced in Embodiment 13 in this order. Next, the liquid crystal color shutter was arranged so as to be in contact with the display screen of a display device 80 including a plurality of black-and-white fluorescent tubes 81 in which the sides of the circularly polarized light conversion sheet were juxtaposed vertically and horizontally to produce a color image display device.

When the switching of the red, green and blue colors of the liquid crystal color shutter is performed in 1 ms or less (for example, 0.9 ms) in synchronization with the image displayed on the black and white fluorescent tube, a color display with high display quality without color flicker is performed. Was able to do. Further, in the liquid crystal color shutter and the color image display device of the present invention, since the color polarizing plate is not used, the transmittance of the light emitted from the display device to the liquid crystal color shutter can be greatly improved, and a bright and high-contrast display can be achieved. Was able to do.

Each of the embodiments described above is an example of the present invention, and the examples described in the embodiments may be combined.

[0124]

As described above in detail, according to the liquid crystal color shutter of the present invention, by stabilizing the helical pitch in the natural state of the cholesteric liquid crystal or chiral nematic liquid crystal, the helical pitch is longer than P ₀ The relaxation process from the state P ₁ (> P ₀ ) can be accelerated, and the operation speed can be increased.

Further, according to the liquid crystal color shutter of the present invention, transition between a plurality of states having a helical pitch longer than the helical pitch P ₀ of the cholesteric liquid crystal or the chiral nematic liquid crystal in the natural state is performed, thereby transmitting transmitted light and reflected light. The wavelength can be controlled at a high speed, and the operating speed can be increased.

In the liquid crystal color shutter of the present invention,
Since it is not necessary to use a color polarizing plate that has limited the light use efficiency, a bright and high-quality liquid crystal color shutter can be provided.

According to the color image display device of the present invention, by employing the above-described liquid crystal color shutter of the present invention, it is possible to display a color image which is bright, has no color flicker, and has excellent display quality. it can.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 2 is a diagram schematically showing an example of a pattern of a comb-like electrode as viewed from a direction of a spiral axis of liquid crystal molecules.

FIG. 3 is a diagram schematically showing another example of the configuration of the liquid crystal color shutter of the present invention.

[4] As the liquid crystal molecules constituting the cholesteric phase is stabilized in a state of natural helical pitch length [rho _0, diagram schematically showing an example in which provided between the substrate polymeric material together with the liquid crystal layer.

FIG. 5 is a diagram for explaining a liquid crystal color shutter of the present invention in which a plurality of states larger than a helical pitch P _{0 in a} natural state are transited.

FIG. 6 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 7 is a view showing an example of a selective reflection spectrum of the liquid crystal color shutter illustrated in FIG. 6;

FIG. 8 is a view for explaining the color of transmitted light corresponding to a set of cells constituting a liquid crystal color shutter according to the present invention when voltage is applied and when voltage is not applied.

FIG. 9 is a diagram showing transmitted light spectra corresponding to a set of cells constituting a liquid crystal color shutter according to the present invention when voltage is applied and when voltage is not applied.

FIG. 10 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 11 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 12 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 13 is a diagram schematically showing an example of the configuration of a liquid crystal color shutter of the present invention.

FIG. 14 is a diagram schematically showing a configuration of a color image display device of the present invention.

FIG. 15 is a diagram illustrating a relationship between a spectrum of light emitted from a display screen of a display device and a selective reflection spectrum of a liquid crystal color shutter.

[Explanation of symbols]

 11 First substrate 12 Second substrate 13 Liquid crystal layer 13a Liquid crystal molecules 14 Comb-like electrode 15 Voltage applying means 16 ……… Pole-shaped electrode 17 ……… Polymer material 20 ……… Liquid crystal color shutter 21,22,23,24… Cell 41,42,43,44,45,46… Cell 51,52, 53, 54 cells 55, 56 λ / 2 plate 61a, 61b, 62a, 62b cell 63 λ / 2 plate 71, 72, cell 73 73 polarized light Conversion sheet 80 Display device 81 CRT 82 Synchronous circuit 83 Raster generator 84 Control circuit

Claims (6)

[Claims] A liquid crystal layer having a cholesteric phase sandwiched between a first substrate and a second substrate; and a liquid crystal layer parallel to a plane direction of the first substrate and the second substrate. Means for applying an electric field in different directions; and between the first substrate and the second substrate, an intermolecular force acting between liquid crystal molecules constituting the liquid crystal layer is a natural helical pitch of the liquid crystal molecules. A polymer composition disposed so as to be the largest at P ₀ . 2. A liquid crystal layer exhibiting a cholesteric phase sandwiched between a first substrate and a second substrate; and a helical pitch of liquid crystal molecules constituting the liquid crystal layer is set to a natural helical pitch P on the liquid crystal layer. Means for applying a first electric field so as to have a _first helical pitch P1 larger than _0;
The second helical pitch P larger than the helical pitch P ₁
Liquid crystal shutter, characterized in that at ₂ equipped with a means for applying a second electric field. 3. A liquid crystal shutter comprising a first substrate and a second substrate, wherein a liquid crystal layer exhibiting a cholesteric phase having a wavelength of selectively reflected light in an ultraviolet region is sandwiched between the first substrate and the second substrate. 4. A liquid crystal layer exhibiting a cholesteric phase sandwiched between a first substrate and a second substrate; and a helical pitch of liquid crystal molecules constituting the liquid crystal layer is set to a natural helical pitch P on the liquid crystal layer. Means for applying a first electric field so as to have a _first helical pitch P1 larger than _0;
The second helical pitch P larger than the helical pitch P ₁
Means for applying a second electric field so as to be ₂ , between the first substrate and the second substrate, an intermolecular force acting between the liquid crystal molecules and a natural helical pitch of the liquid crystal molecules. A liquid crystal shutter comprising a polymer composition disposed so as to be largest in a region of P ₀ or less. 5. A means for displaying an image having a gradation corresponding to color information on a display screen, and wherein the means is provided on the display screen. A color image display device, comprising: the liquid crystal shutter according to any one of the above. 6. The color image display device according to claim 5, wherein a spectrum of light emitted from the display screen corresponds to a selective reflection spectrum of a liquid crystal layer constituting the liquid crystal shutter.