JPS6143702A - Optical filter and its production - Google Patents

Abstract

PURPOSE:To obtain an optical notch filter having excellent function by laminating a pair of solid polymer films having the cholesteric liquid crystal structures of the spiral structures opposite from each other in the winding direction in such a manner that the optical axes thereof are made approximately parallel with each other and that both films are held in direct contact with each other. CONSTITUTION:The solid polymer film 1 fixed with the cholesteric liquid crystal of the either right-handed or left-handed spiral structure having the spiral pitch to scatter selectively the light of the specific wavelength in a visible region is manufactured by subjecting the cholesteric liquid crystal consisting of a soln. mixture composed of a polypeptide compd. and radiation polymerizable monomer to planar orientation then to radiation polymn. The solid polymer film 2 fixed with the cholesteric liquid crystal of the spiral structure having the winding direction opposite from the above-mentioned winding direction is formed by using the soln. mixture consisting of the components or component ratio different from the above-mentioned soln. mixture and is laminated on the surface of the above-mentioned polymer film in such a manner that the optical axes of both films are made approximately parallel with each other and that both films are held in direct contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical filter used in color displays and the like.

2. Description of the Related Art Conventional Structure and Problems Conventional color displays generally use a red (R) filter (a filter that transmits only red light), a green (G) filter, and a blue (B) filter. For example, for full-color image display, a filter is used in which a large number of iR, G, and B fine filters are arranged as one pixel. In this case, the 01
This is desirable for widening the color reproduction range in a chromaticity diagram. However, in reality, KR, G,
Each of the H filters has a mutually overlapping portion in the spectral wavelength region. Therefore, a filter that cuts (does not transmit) light in the overlapping wavelength range between R and G, the overlapping wavelength range between G and B, or the noise wavelength from the light source.

In other words, an optical notch filter is required.

On the other hand, it has been well known that cholesteric liquid crystals exhibit optical properties such as selective light scattering, optical rotation, and circular dichroism. A technique for applying the optical properties of cholesteric liquid crystal to an optical notch filter has been invented (Japanese Patent Publication No. 53-2330).

In other words, a pair of liquid crystal films, a right-handed spiral cholesteric liquid crystal film and a left-handed spiral cholesteric liquid crystal film, cuts (does not transmit) light in a specific wavelength range of incident light, but blocks light outside the specific wavelength range. The principle of an optical notch filter using a so-called cholesteric liquid crystal that transmits light is disclosed. However, after dissolving the cholesteric liquid crystal composition in an organic solvent such as oo-form or petroleum ether and developing it into a film, the temperature at which the cholesteric liquid crystal component transforms into an isotropic liquid is normally set in this cholesteric liquid crystal film. By heating to 60'C or more to evaporate the organic solvent component and directly bond the cholesteric liquid crystal component, a film having a cholesteric liquid crystal structure can be obtained at a temperature around room temperature.

The helical pitch of this cholesteri ivy liquid crystal film essentially depends on temperature, pressure, electric field, magnetic field, and chemical vapor.

It changes due to external stimuli such as ultraviolet light. Therefore, in order to put this cholesteric liquid crystal film into practical use as a light filter, a constant temperature bath is required to keep the KHl holding temperature constant, and to protect the film from moisture, alcohol, and other chemical vapors in the atmosphere. This cholesteric liquid crystal film had the disadvantage of requiring a protective film such as a glass plate or Mylar sheet, and was not a practical cholesteric liquid crystal film as a stable optical notch filter. Additionally, this film is usually sticky, soft, viscous, glassy or liquid, and therefore
A protective film is required to protect the film from foreign substances such as dust and insects. In addition, an optical notch filter requires a pair of films, a right-handed cholesteric liquid crystal film and a left-handed cholesteric liquid crystal film, but conventional films require a transparent spacing member between the pair of films. Therefore, reflection loss and absorption loss of light occur, and the optical Norichi filter has the essential drawback that the light transmittance of the optical Norichi filter for light having wavelengths other than the specific wavelength range decreases accordingly.

On the other hand, by polymerizing a lyotropic liquid crystal consisting of a mixed solution of a cholesteric liquid crystal component and a compound with a polymerizable unsaturated group, the cholesteric liquid crystal structure is fixed, and its helical pitch changes at a certain temperature.

A technique for producing solid polymer films that are extremely stable against external stimuli such as light, electric fields, and magnetic fields has been invented (Japanese Patent Application Laid-Open No. 139506/1983). This cholesteric liquid crystal
It can be said that the invention of polymer composites has paved the way for the practical application of passive optical elements that utilize the optical properties of cholesteric liquid crystals. However, the present invention does not disclose a technique in which at least one pair of cholesteric liquid crystal films necessary for the optical filter is laminated by aligning the optical axes of both films in parallel and bringing the two films into direct contact. do not have.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a stable optical filter that is based on the invention of a cholesteric liquid crystal/polymer composite and exhibits excellent functionality as an optical notch filter. To be more specific, it is possible to freely select the wavelength range of the light to be cut, and also to control the width of the wavelength range of the light to be cut, and also to control the transmission within the wavelength range of the light to be cut. It is an object of the present invention to provide an optical notch filter that can almost completely cut out light and can also almost completely transmit transmitted light outside the wavelength range of the light to be cut.

Components of the Invention The optical filter of the present invention has a cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer in a planar orientation, and selectively scatters light of a specific wavelength in the visible region that undergoes radiation polymerization. with a circular pitch,
A solid polymer film having a cholesteric liquid crystal structure with either a right-handed or left-handed helical structure, and a polypeptide compound and a radiation-polymerizable monomer having chemical components whose ratios are different from those of the mixed solution. A cholesteric liquid crystal consisting of a mixed solution of In this method, a solid polymer film having a cholesteric liquid crystal structure with a helical structure and a solid polymer film having a helical structure wound in the opposite direction are made so that the optical axes of both films (the direction in which the cholesteric liquid crystal is laid) are almost parallel to each other, and the two films are brought into direct contact with each other. It consists of a laminated structure. When white light is incident on this filter, the right-handed circularly polarized light component (by the right-handed helical cholesteric liquid crystal film layer) and the left-handed circularly polarized light component (by the left-handed helical cholesteric liquid crystal film layer) of the specific wavelength are separated by both layers. Since it is reflected, the light of the specific wavelength is ultimately cut out from the transmitted light. Furthermore, since both layers of the filter σ of the present invention are directly laminated, and the average refractive index of light in both layers can be easily made equal, the reflection loss of light transmitted through the filter is rrf! ＜The characteristic is that the transmittance of light having wavelengths other than the specific wavelength is extremely high.

Next, in the method for producing an optical filter of the present invention, a cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer is applied in a planar orientation, and then, while maintaining the holding temperature at a predetermined constant temperature, the cholesteric liquid crystal is By polymerization, we create a solid polymer film fixed with a cholesteric liquid crystal with either a right-handed or left-handed helical structure that has a helical group pinch that selectively scatters light of a specific wavelength in the visible region, and A cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer, which has a different chemical component or component ratio from the mixed solution, is planarly oriented on the surface of a cholesteric liquid crystal having a helical structure in a winding direction opposite to the helical winding direction, having a helical group pinch that selectively scatters light of the same wavelength as the specific wavelength by radiation polymerization while maintaining the temperature at a constant temperature; The method consists of the step of laminating solid polymer films with fixed polymers such that the optical axes of both films are substantially parallel and the two films are in direct contact with each other.

When the chemical composition of the mixed solution of a polypeptide compound and a radiation-polymerizable monomer is fixed, the helical pitch of the cholesteric liquid crystal corresponding to the selective scattering of light at the specific wavelength is determined by the holding temperature during radiation polymerization. therefore,
It is necessary to maintain the cholesteric liquid crystal at a predetermined constant temperature until the radiation polymerization process is completed. After radiation polymerization is completed, Vci is fixed to the helical pitch of the cholesteric liquid crystal by the three-dimensional network structure of the polymer, so even if the environmental temperature changes, the helical pitch hardly changes, and it is determined during radiation polymerization. If it is, the magnitude of the rotational pitch is maintained. Furthermore, in the manufacturing method of the present invention, another cholesteric liquid crystal solution is directly applied onto the surface of the polymer film on which the cholesteric liquid crystal, which has already been planarly oriented and whose spiral glaze direction is perpendicular to the film surface, is fixed by radiation polymerization. Regardless of whether the spiral is right-handed or left-handed, the coated cholesteric liquid crystal tends to have a planar orientation (the spiral glaze is oriented extremely perpendicular to the underlying film surface). Therefore, it is easy to stack and integrate the right-handed spiral cholesteric liquid crystal film by making the direction of the spiral glaze (optical axis) parallel to the direction of the spiral glaze (optical axis) of the left-handed spiral cholesteric liquid crystal film. This is one of the features of the manufacturing method of the present invention.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows an optical notch filter according to an embodiment of the present invention. This example is a configuration for cutting a single wavelength region. This is a right-handed helical liquid crystal film, which is a solid polymer film on which cholesteric liquid crystal with a right-handed helical structure is fixed. The cholesteric liquid crystal spiral glaze is oriented in the direction perpendicular to the film surface. A left-handed spiral liquid crystal film 2 is directly laminated on a right-handed spiral liquid crystal film 1. This is a solid polymer film in which a cholesteric liquid crystal with a left-handed spiral structure is fixed to a left-handed spiral liquid crystal film 2, and the liquid crystal spiral glaze is oriented in a direction perpendicular to the film surface. When the above laminated film is irradiated with white light almost perpendicularly to the film surface from the side of the right-handed helical liquid crystal film 1, only the right-handed circularly polarized light component 4 with a specific wavelength λo3 of the white light is emitted from the right-handed helical liquid crystal film. 1 and then transmitted through the right-handed helical liquid crystal film 1. Of the light, only the left-handed circularly polarized light component 6 with a specific wavelength λ0 is reflected by the left-handed helical liquid crystal film 2, and the reflected light of the left-handed circularly polarized light is As a result, by the optical filter of the present invention, only lights 4 and 6 with a specific wavelength λ0 are reflected by the optical filter of the present invention, and light θ other than λ0 is transmitted through the right-handed helical liquid crystal film 1. It turns out. In other words, it functions as an optical notch filter that inputs only light having a specific wavelength λ0 to the optical filter of the present invention.

Here, if the helical pitch of the cholesteric liquid crystal fixed as a solid polymer film is p, the average optical refractive index is n, and the birefringence of the cholesteric layer is Δn, then an optical filter (optical notch filter) is used to cuff) The wavelength of the emitted light essentially has a width of Δλ centered at λ0. Here, λ(Irrp” is equal to the product ΔλH2p・Δn/π (if the film thickness is sufficiently large). If the incident light is deviated from the direction perpendicular to the film surface by an angle θ, then λG=1 )@ncO8θ.Actually, since there is a distribution in the degree of orientation of the helical axis, the degree of twist of the helix, the helical pitch, etc., there is a spectroscopic distribution in λ0.In other words, the width of the distribution of λ0 This can be controlled by adjusting the degree of orientation of the helical axis of the cholesteric liquid crystal (for example, the degree of orientation in the direction perpendicular to the film plane) and the width of the distribution of the helical axis and Sochi. An important point in the configuration is that [1] the condition r-nr=pI''g must be satisfied. Here, pr is the helical pitch of the right-handed cholesteric liquid crystal, nru is its average refractive index, p6rz is the helical pitch of the left-handed coccosteric liquid crystal, and ng is its average refractive index. Furthermore, it can be determined that the desirable configuration of the optical filter of the present invention satisfies the condition rx nr = n6 (therefore, pr = pl). At this time, reflection loss can be eliminated when light other than the specific wavelength λ0 passes through the filter. The average refractive index of each film layer can be adjusted by adjusting the chemical composition of the liquid crystal solution, and the size of the helical pitch can be adjusted by setting the holding temperature during photopolymerization.

In a typical example of the production process of the polymer film of the present invention, first, a polypeptide compound as a liquid crystal raw material and a monomer having a radiation-polymerizable unsaturated group as a solvent are sufficiently mixed to form a cholesteric liquid crystal solution (lyotropic liquid crystal state). The concentration is adjusted so that a predetermined helical pitch is achieved, the temperature is adjusted, and radiation polymerization is carried out while maintaining this temperature. By changing the concentration C and temperature T when preparing the cholesteric liquid crystal solution, as well as the types of polypeptide compounds and radiation-polymerizable monomers used, the cholesterol fixed in the finished VoIJmer film can be adjusted. It is possible to easily control the visibility of a liquid crystal, and also to change the direction of right-handed or left-handed.

Therefore, we create a polymer film fixed with a right-handed cholesteric liquid crystal whose pr-nr product is controlled so that it is equal to the specific wavelength λ0 in the visible region that we want to cut, and further on the film surface, the pl”nll product becomes equal to λ0. By creating a polymer film fixed with a left-handed coccholesteric liquid crystal controlled as follows (preferably so that pl=pr and n1=nr), a laminated film having an excellent function as an optical notch filter can be obtained. .

Another important point here is to align the directions of the helical axes (optical axes) of each cholesteric liquid crystal part fixed in the polymer film, and to align the directions of the helical axes of the right-handed cholesteric liquid crystal and the directions of the helical axes of the left-handed cholesteric liquid crystal. It is necessary to make the directions of the helical axes parallel to each other, and it is desirable to orient the helical axes perpendicularly to the plane of the polymer film in order to obtain a sharp optical notch filter. In general, a cholesteric liquid crystal solution (lyotropic liquid crystal state) is held between glass plates with a pure surface or glass plates whose surfaces have been subjected to alignment treatment to make the cholesteric liquid crystal planarly aligned (the helical axis is aligned perpendicular to the glass surface). I can do it. Furthermore, when another cholesteric liquid crystal solution is applied onto the surface of a polymer film containing cholesteric liquid crystals that have already been planarly oriented, the helical axis will align with the underlying film surface, regardless of the right-handed or left-handed helical direction. Very easy to align vertically (planar alignment of cholesteric liquid crystal). Therefore, it is easy and advantageous to laminate and integrate a polymer film containing oriented cholesteric liquid crystal with a right-handed helical structure and a polymer film containing oriented cholesteric liquid crystal with a left-handed helical structure. This is one of the features of the present invention.

In addition, the optical filter of the present invention includes a helical pitch that selectively scatters light with the same wavelength λ0 as a right-handed cholesteric liquid crystal (refractive index nr) polymer film with a helical pitch 1) r that selectively scatters light with a specific wavelength λ0; Left-handed Coreste with Sochi Tel January Tsuku liquid crystal (refraction thread ng) and right-handed with a two-layered polymer film and a group pitch pr' that selectively scatters light with another specific wavelength λ0' different from λ0. Adding two layers of a cholesteric liquid crystal (refractive index nr') polymer film and a left-handed cholesteric liquid crystal (refractive index ne') polymer film with selective scattering of light of the same wavelength λ0' and a pitch pe', It is also possible to have a structure in which the optical axes are made substantially parallel to each other and stacked. Here, when the helical axis (optical axis) of the cholesteric liquid crystal is aligned perpendicularly to each film surface and white light is irradiated parallel to the helical axis, λ0=pr'' ``r=1) l
"n l*λo' = 1) r"nr' = pe'
.

The material is designed to satisfy the condition n6' (where λ0\λo'). When the four-layer film is irradiated with white light, only the light with a specific wavelength λ0 and another specific wavelength λ0' are selectively reflected, and all the light with other wavelengths is transmitted through the four-layer film. Therefore, it functions as a multi-notch filter that can simultaneously filter the light of λG and the light of λ0'. In this way, the right-handed spiral beam corresponding to the wavelength λ of the light to be cut1. H1) Having r; Making a pair of Lestelink liquid crystal film and a cholesteric liquid crystal film with left-handed spiral bi-nochipe, and increasing the number of film layers in the pair while changing the wavelength λ of the light to be cut. Thus, a desired multi-notch filter can be obtained. More preferably, nr=no-nr'=ne'
Materials can be designed to meet these conditions.

The optical filter of the present invention also includes a transparent film and a transparent plate.

Color filters, multicolor color filters, polarizing plates.

It can also be laminated or integrated with one or more types of films and plates such as a color polarizing plate, a V4 wavelength plate, and an A wavelength plate. Generally, LCD display.

Transparent plates (glass substrates, etc.) and transparent films (transparent organic protective films, transparent organic alignment films, transparent electrodes, etc.) are used in displays such as electrochromic displays, electroluminescent displays, and cathode ray tube displays, depending on the purpose.
, color filters, multicolor color filters, polarizing plates (linear polarizing plates, 9 circularly polarizing plates), color polarizing plates, quarter-wave plates, double-wave plates, and the like are used. In the process of manufacturing the cholesteric liquid crystal polymer film of the present invention, by laminating and integrating the above films and plates, it is possible to improve workability and reduce costs.

Further, by providing a transparent protective film on the surface of the optical filter film of the present invention, moisture resistance, light resistance, gas resistance, etc. can be improved.

The liquid crystal raw material used in the optical filter of the present invention may basically be any material that can form a cholesteric liquid crystal (provided that the solvent is a monomer having a radiation-polymerizable unsaturated group). Polymers are well known as substances that can form lyotropic liquid crystals in organic solvents, and among them, polymers with peptide bonds (rod-like molecules with a helical structure) tend to form stable cholesteric liquid crystal solutions. Furthermore, among polypeptide compounds, polymer frames of acidic amino acids and their ester derivatives, as well as monomers with unsaturated groups as solvents, are radiation-polymerized to maintain an extremely stable cholesteric liquid crystal structure even after they are fixed in a polymer film. I can do it. There are three types of acidic amino acids: aspartic acid, glutamic acid, and oxyglutamic acid. In addition, these ester derivatives include many substances such as methyl ester, ethyl ester, 7"a hill ester, butyl ester, pentyl ester, hexyl ester, cyclohexyl ester, benzyl ester, and chlorobenzyl ester of acidic amino acids. Polymeric amino acids and polymeric amino acid derivatives obtained by polymerizing acidic amino acids and their derivatives are used as liquid crystal raw materials, and acrylic, methacrylic, or methacrylic monomers having at least one unsaturated group are used as radiation polymerizable monomers. Allyl-based compounds are preferable, including acrylic and methacrylic-based aliphatic polyols.

Poly(meth)acrylate, alkylene oxide (
Uses meth)acrylic esters, (meth)acrylic esters of polyols with alkylene oxide added to phenols, cyclopentadiene (meth)acrylates, di(meth)ketarylates of bisphenols and ethylene oxide adducts, etc. However, polyethylene glycol dimethacrylate such as triethylene glycol dimethacrylate or tetraethylene glycol dimethacrylate is preferred because of its low viscosity and ease of radiation polymerization. When ultraviolet rays are used in radiation polymerization, benzophenone, benzoin, and acetophenone polymerization initiators can be used as photosensitizers.

Example 1 60% by weight of poly-L-glutamic acid n-butyl ester as a liquid crystal raw material, 60% by weight of triethylene glycol dimethacrylate as a solvent and photopolymerizable monomer,
Each was weighed, and both were thoroughly stirred and mixed while maintaining the temperature at 40 to 60°C. To the thus obtained homogeneous liquid crystal solution, 1 g of benzophenol was further added as a photosensitizer. This mixed solution was sandwiched between two clean glass plates, and while the temperature of the plates was maintained at a constant temperature of 30"C, ultraviolet rays were applied to the mixture using an ultra-high pressure mercury lamp.
The monomer was polymerized by irradiation for a period of time to obtain a polymer film with a thickness of 0.2 m on which cholesteric liquid crystal was fixed. As a result of optical measurements on this film, it was found that this film has strong selective reflection (reflectance of 46%) at the center wavelength of 490 nm.
), and it was confirmed that the light reflected right-handed circularly polarized light.

Next, as a raw material for liquid crystal, poly-D-glutamic acid n-butyl ester (70,000 mol.
Fifty grams of triethylene glycol dimethacrylate as a solvent and a photopolymerizable monomer were each weighed out, and the two were sufficiently stirred and mixed while maintaining the temperature at 4°C to 60°C.

To the homogeneous liquid crystal solution thus obtained was further added 1 g of benzophenone as a photosensitizer. This mixed solution B
was sandwiched between the stone-wrapped cholesteric liquid crystal polymer film and a glass plate, and while maintaining the temperature of both at a constant temperature of 30°C, UV rays were irradiated for 6 hours to polymerize the monomer, thereby forming cholesteric liquid crystal. Fixed thickness 0
．． 2 m of polymer films were newly laminated to create a two-layer laminated film. On the other hand, as a result of measuring the mechanical properties of this polymer film alone, it was confirmed that it exhibited strong selective reflection (reflectance of 46%) at a center wavelength of 490 nm and exhibited left-handed circularly polarized light reflection. Next, as a result of optical measurement of the two-layer laminated film, this laminated film showed strong selective reflection (reflectance 90%) at a center wavelength of 490 nll.
It was confirmed that it exhibits right-handed circularly polarized light reflection and left-handed circularly polarized light reflection. In other words, this laminated film is used as an optical filter that has the function of an optical notch filter that almost (90%) cant light with a specific wavelength of 490 nm or 15 nm in the visible region, and transmits almost (88%) light other than 490 nm ± 151 m. be able to.

Example 2 On top of the two-layer laminated film obtained in Example 1, m layers of another polymer film were formed.

First, the mixed solution prepared in Example 1 was sandwiched between the laminated film obtained in Example 1 and a glass plate, and an ultra-high pressure mercury lamp was used while keeping the temperature of both at a constant temperature of 43°C. The monomer was polymerized by irradiating ultraviolet rays for 6 hours using a cholesteri 9. A 3-layer laminated film was created by newly laminating a polymer film with a thickness of 0.2 mm on which the liquid crystal was fixed.

On the other hand, as a result of measuring the optical properties of this polymer film alone, we found that there was strong selective reflection at the center wavelength of 5801u (reflectance of 43
%) and was confirmed to exhibit right-handed circularly polarized light reflection.

Next, the mixed solution B prepared in Example 1 was sandwiched between the three-layer laminated film and the glass plate, and irradiated with ultraviolet rays for 5 hours while maintaining the temperature of both at a constant temperature of 43°C. The monomers were polymerized, and a 0.2 nm thick polymer film on which cholesteric liquid crystal was fixed was newly laminated to create a four-layer laminated film. On the other hand, as a result of measuring the optical properties of this polymer film alone, the center wavelength was 5.
It was confirmed that strong selective reflection (reflectance of 44 cm) was observed at 801 m, and counterclockwise circularly polarized light was reflected.

Next, as a result of optical measurement of the above four-layer laminated film, as shown in the spectral characteristics in Figure 3, the center wavelength was 490.
It was confirmed that strong selective reflection was observed at two locations at nm and 580 nm (reflectance at each wavelength was 90 cm and 87 cm, respectively), and clockwise circularly polarized light reflection and counterclockwise circularly polarized light reflection were exhibited at each wavelength. Ta.

In other words, this four-layer laminated film has a multi-notch that simultaneously cuts light with a specific wavelength of 4901 m ± 15 nm in the visible region and light with a wavelength of ssonm ± 151 m, and allows light other than those specific wavelengths to pass through almost (8 ends). It can be used as an optical filter with a filter function.

Next, a full-color image display experiment was conducted using a liquid crystal cell equipped with a white light source and a three-primary mosaic color filter having the spectral characteristics shown in FIG.

At this time, the color reproduction range was measured in the case where only the white light source and the above color filter were used, and in the case where the No-Nochi filter of the present invention having the spectral characteristics shown in Fig. 3 was further placed between the white light source and the above color filter. As a result of comparison, in the former case (
Compared to the color reproduction range of the conventional example), the color reproduction range of the latter case (present invention example) is wider (approximately 12 inches in area of the chromaticity diagram).

Example 3 A horizontal alignment film of polyimide was formed on the surface of a transparent glass substrate, and the same mixed solution as used in Example 1 was applied onto the alignment film to a uniform thickness using a spinner, and heated at 30″C. The monomer was polymerized by irradiating ultraviolet rays for 1 hour while maintaining the temperature at The same mixed solution B was applied to a uniform thickness using a spinner, and the monomer was polymerized by irradiating it with ultraviolet rays for 1 hour while maintaining the temperature at 30°C.A left-handed cholesteric liquid crystal polymer film with a thickness of 20 μm was laminated. On top, the same mixed solution was applied to a uniform thickness, and the monomer was polymerized by irradiating it with ultraviolet rays for 1 hour while maintaining the temperature at 43°C, resulting in a 2-μm thick layer.
A right-handed cholesteric liquid crystal polymer film of
The monomers were polymerized by irradiation for a period of time, and a 20 μm thick kicholesteric liquid crystal polymer film was laminated thereon. That is, the optical filter of the present invention was obtained by laminating and integrating a glass substrate and four layers of films. As a result of measuring the spectral characteristics of this optical filter, the spectral characteristics shown in FIG. 4 were obtained. This optical filter uses 4 specific wavelengths in the visible region.
It is possible to almost completely cut out 90nm±1OnIn light and ssonm±1Onll light at the same time (98% and 96% reflectance at each wavelength, respectively), and almost completely cut out light other than those specific wavelengths (93%). ) Transmits light In addition to being used as a multi-notch filter, since it is integrated with a transparent glass substrate, it can also be used, for example, as a substrate for a liquid crystal display cell. The multi-notch filter of the third embodiment has a sharper reflection peak at a specific wavelength than the multi-notch filter of the second embodiment. That is, the half width G1 of the reflection peak is small and the height of the peak is large. The reason for this is that the degree of orientation of the individual cholesteric liquid crystals fixed in the polymer film (in the direction perpendicular to the film surface) has improved, and the distribution of the helical pitch has become narrower. Effects of the Invention As described above, according to the optical filter of the present invention, each polymer film contains orients right-handed and left-handed helical cholesteric liquid crystals in which the product of helical pitch and optical refractive index is constant. By stacking them as a pair,
It has excellent performance such as being able to freely select the wavelength range of the light to be focused and sorted, controlling the width of that wavelength range, and almost completely cutting out transmitted light within that wavelength range. A low-cost, lightweight optical filter can be obtained. By using these optical notch filters, for example, in full-color image display, the color purity is improved, and excellent color display with a wider color reproduction range becomes possible.

In addition, costs can be reduced by laminating and integrating the optical filter of the present invention with a polymer film fixed with a cholesteric liquid crystal that functions as an optical notch filter, and a film or plate widely used in display devices. 9. Improved workability, improved reliability, improved stability, etc. can be obtained, and it has high economic and technical value.

[Brief explanation of drawings]

FIG. 1 is a graph showing an example of the spectral characteristics of a mosaic color filter of three primary colors, which is generally used for full-color image display.
Fig. 2 is a cross-sectional view explaining the configuration of the optical filter of the present invention and its function as an optical norchi filter, and Figs. 3 and 4 show examples of spectral characteristics of the optical filter of the present invention having a function as a multi-notch filter. This is a graph showing. 11... Right-handed spiral liquid crystal film, 12...
...Left-handed helical liquid crystal film, 13...Incoming light with a specific wavelength λ0, 14...Right-handed circularly polarized reflected light with a specific wavelength λ0, 16...Specific wavelength λ0 Left circularly polarized reflected light, 16... Light other than the specific wavelength λ0. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 4 of vjs diagram

Claims (7)

[Claims] (1) A cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer is planarly oriented and radiation-polymerized, with a right-handed or left-handed helical pitch that selectively scatters light of a specific wavelength in the visible region. A cholesteric liquid crystal consisting of a solid polymer film having one of the helical cholesteric liquid crystal structures, and a mixed solution of a polypeptide compound and a radiation-polymerizable monomer, which have different chemical components or component ratios from the mixed solution. has a cholesteric liquid crystal structure with a helical pitch that selectively scatters light of the same wavelength as the specific wavelength and a spiral structure in a winding direction opposite to the winding direction of the spiral, which is obtained by planar orientation and radiation polymerization. 1. An optical filter comprising a pair of films formed by laminating a solid polymer film with the optical axes of both films substantially parallel and in direct contact with each other. (2) A patent claim comprising at least two pairs of films, each pair having a different specific wavelength for selective scattering, the optical axes of the films being substantially parallel to each other, and the films being laminated in direct contact with each other. The optical filter according to the range 1 above. (3) The optical filter according to claim 1 or 2, wherein the optical refractive index of each layer constituting the film pair is substantially equal to each other. (4) Claim 1 in which the polypeptide compound is a polyacidic amino acid or a polyacidic amino acid ester derivative
The optical filter according to item 1 or 2. (5) The optical filter according to claim 1 or 2, wherein the radiation polymerizable monomer is an acrylic compound, a methacrylic compound, or an allyl compound having at least one unsaturated group. (6) After planarly aligning a cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer, the cholesteric liquid crystal is subjected to radiation polymerization while maintaining its holding temperature at a predetermined constant temperature, thereby producing light of a specific wavelength in the visible region. A solid polymer film fixed with a cholesteric liquid crystal having either a right-handed or left-handed helical structure with a helical pitch that selectively scatters the Cholesteric liquid crystals made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer with different component ratios are planarly aligned and then subjected to radiation polymerization while maintaining the holding temperature at a predetermined constant temperature. A solid polymer film fixed with a cholesteric liquid crystal with a helical structure having a helical pitch that selectively scatters light of the same wavelength as the above-mentioned helical winding direction is opposite to the winding direction of the spiral, and the optical axes of both films are approximately aligned. A manufacturing method for optical filters in which both films are laminated in parallel and in direct contact. (7) Transparent film, transparent plate, color filter, multicolor color filter, polarizing plate, color polarizing plate, 1/4 wavelength plate or 1/4 wavelength plate
At least one of the two-wavelength plates is used as a substrate, and after a cholesteric liquid crystal made of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer is planarly aligned on the surface of the substrate, its holding temperature is maintained at a predetermined constant temperature. Solid polymer films fixed with cholesteric liquid crystals with either a right-handed or left-handed helical structure with a helical pitch that selectively scatters light of a specific wavelength in the visible region are laminated together by radiation polymerization while maintaining a constant temperature. Further, on the surface of the film, a cholesteric liquid crystal consisting of a mixed solution of a polypeptide compound and a radiation-polymerizable monomer, which has a different chemical composition or component ratio than the mixed solution, is planarly oriented, and then the holding temperature is Cholesteric cholesteric with a helical structure in a winding direction opposite to the winding direction of the helix, which has a helical pitch that selectively scatters light of the same wavelength as the specific wavelength by radiation polymerization while keeping it at a predetermined constant temperature. A method for manufacturing an optical filter, in which a solid polymer film on which a liquid crystal is fixed is laminated and integrated by making the optical axes of the right-handed cholesteric film and the left-handed cholesteric film substantially parallel, and by bringing the two films into direct contact.