JP4286385B2 - Method for manufacturing polarization diffraction element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a polarization diffraction element capable of generating diffracted light having polarization.
[0002]
[Prior art]
A diffractive element is a general-purpose optical element that is widely used in the field of spectroscopic optics and the like for the purpose of spectrally dividing light or splitting a light beam. Diffraction elements are classified into several types according to their shapes. Amplitude-type diffractive elements in which light transmitting parts and non-transmitting parts are arranged periodically, phase type in which periodic grooves are formed in highly transmissive materials Usually classified as a diffraction element. In some cases, the diffractive light is classified as a transmissive diffractive element or a reflective diffractive element depending on the direction in which the diffracted light is generated.
[0003]
In the conventional diffractive element as described above, the diffracted light obtained when natural light (unpolarized light) is incident can only obtain non-polarized light. Polarized optical instruments such as ellipsometers frequently used in the field of spectroscopic optics, etc. can only obtain unpolarized light as diffracted light. In order to use only the polarized light component, a method of using diffracted light through a polarizer is generally performed. This method has a problem that the amount of light is reduced by half because about 50% or more of the obtained diffracted light is absorbed by the polarizer. For this reason, it is necessary to prepare a highly sensitive detector and a light source with a large amount of light, and there has been a demand for the development of a diffractive element in which the diffracted light itself becomes specific polarized light such as circularly polarized light or linearly polarized light.
[0004]
[Problems to be solved by the invention]
This invention solves the said subject, and succeeded in providing diffraction power to the one part area | region of a cholesteric alignment film by controlling a liquid crystal layer structure. More specifically, the present inventors finally found a method for easily imparting a new characteristic called diffraction ability to a cholesteric alignment film in addition to selective reflection characteristics and circular polarization characteristics peculiar to cholesteric liquid crystals.
[0005]
[Means for Solving the Problems]
That is, in the present invention, the weight average molecular weight Mw measured by GPC (polystyrene conversion) on the oriented support substrate is 1,000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity is 0.00. 05 to 2.0 (concentration 0.5 g / dl (temperature 30 ° C.) in a mixed solvent of phenol / tetrachloroethane (weight ratio 60/40)), glass transition temperature (Tg) 200 ° C. or less, and isotropic from liquid crystal phase Phase transition temperature (Ti) is 40 ° C. or higher Liquid crystalline polyester A first step of forming a cholesteric alignment film comprising: a second step of transferring a diffraction pattern of a diffractive element substrate onto the surface of the cholesteric alignment film; an adhesive layer 1 comprising the cholesteric alignment film surface having the diffraction pattern transferred thereon and the support substrate 1 The third step of laminating via the first layer, the fourth step of removing the alignment support substrate used in the first step from the cholesteric alignment film, and the cholesteric alignment film surface from which the alignment support substrate has been removed and the support substrate 2 are bonded to the adhesive layer 2. A fifth step of laminating via a polarization diffraction element.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described. In the first step of the present invention, the weight average molecular weight Mw measured by GPC (polystyrene conversion) on the oriented support substrate is 1,000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity 0.05 to 2.0 (concentration 0.5 g / dl (temperature 30 ° C.) in a mixed solvent of phenol / tetrachloroethane (weight ratio 60/40)), glass transition temperature (Tg) 200 ° C. or less, and liquid crystal phase Liquid crystal having a transition temperature (Ti) from isotropic phase to isotropic phase of 40 ° C. or higher (Liquid crystal polyester) Is a step of forming a cholesteric alignment film.
[0007]
Liquid crystalline polyester When the weight average molecular weight (Mw) measured by GPC (polystyrene conversion) is less than 1000, the resulting cholesteric alignment film has low mechanical strength, which is undesirable in various post-treatment steps and practical performance. Further, when transferring the diffraction pattern described in the second step, there is a possibility that transfer that can withstand practicality cannot be performed. On the other hand, if it exceeds 100,000, the fluidity of the liquid crystal deteriorates and the orientation may be adversely affected, and the film may be cracked or cracked when the diffraction pattern is transferred in the second step. On the other hand, when the molecular weight distribution exceeds 5, the meltability and solubility in the solution at the time of preparing the cholesteric alignment film are deteriorated, and it is difficult to obtain uniform alignment in the cholesteric phase, which may cause a practical problem. In addition, when transferring the diffraction pattern in the second step, the film may be cracked or cracked. On the other hand, when the logarithmic viscosity is less than 0.05, the mechanical strength of the cholesteric oriented film may be lowered, which is not desirable in terms of various post-processes and practical performance. In addition, when transferring the diffraction pattern in the second step, there is a possibility that the transfer cannot withstand the practicality. On the other hand, if it exceeds 2.0, the fluidity of the liquid crystal deteriorates and it may be difficult to obtain a uniform orientation to the cholesteric phase, and the film is cracked or cracked when transferring the diffraction pattern described in the second step. There is a risk of entering. Further, when the glass transition temperature (Tg) is higher than 200 ° C., there is a possibility that the liquid crystal state has poor fluidity and it is difficult to obtain uniform alignment, and it is difficult to select an alignment support substrate used during alignment if necessary. Problems can also arise. Furthermore, if the transition temperature (Ti) from the liquid crystal phase to the isotropic phase is lower than 40 ° C., the alignment stability of the cholesteric alignment film near room temperature may be deteriorated, and the transferred diffraction in the cholesteric alignment film after transferring the diffraction pattern It is not desirable because the pattern may be damaged.
[0008]
The polymer liquid crystal used in the present invention satisfies the above various physical properties. Liquid Crystalline polyester is desirable. Preferred examples of the structural unit of the polymer include aromatic or aliphatic diol units, aromatic or aliphatic dicarboxylic acid units, and aromatic or aliphatic hydroxycarboxylic acid units.
[0009]
In addition, in order to improve the heat resistance of the finally obtained cholesteric alignment film, a crosslinking agent such as a bisazide compound or glycidyl methacrylate can be added in a range that does not interfere with the expression of the cholesteric phase in the film material, By adding these crosslinking agents, crosslinking can be performed in a state where a cholesteric phase is expressed. Furthermore, various additives such as dichroic dyes, dyes, and pigments can be appropriately added to the film material as long as the effects of the present invention are not impaired.
[0010]
In the first step of the present invention, the film material as described above is arranged on an oriented support substrate to obtain a cholesteric oriented film. Examples of the orientation support substrate that can be used in the first step include a glass substrate, a plastic substrate such as a plastic film, and a plastic sheet. As the glass substrate, for example, soda glass, silica-coated soda glass, borosilicate glass substrate, or the like can be used. Plastic substrates include olefinic resins such as polypropylene, 4-methylpentene-1 resin, amorphous polyolefin, polyamide, polyimide, polyamideimide, polyetherimide, polyetherketone, polyetheretherketone, polyethersulfone, polyketonesulfide. And cellulose-based plastics such as polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyacetal, polycarbonate, polyvinyl alcohol, and triacetyl cellulose. These alignment support substrates can be appropriately subjected to a uniaxial or biaxial stretching operation as necessary. Further, the substrate can be subjected to a surface treatment such as a hydrophilic treatment, a hydrophobic treatment, or an easily peelable treatment. Further, as the alignment support substrate, one type alone or a laminate of two or more types of substrates can be used as the alignment support substrate.
[0011]
Moreover, what formed the alignment film on each said alignment support substrate is also included in an alignment support substrate in this invention. As the alignment film, a rubbed polyimide film is preferably used, but other alignment films known in the field can also be used as appropriate. Further, a plastic substrate or the like obtained by imparting alignment ability by direct rubbing treatment without applying polyimide or the like can also be used as an alignment support substrate for obtaining a cholesteric alignment film. The alignment treatment method is not particularly limited as long as it aligns liquid crystal molecules uniformly and parallel to the alignment treatment interface.
[0012]
Next, as means for applying the film material on the orientation support substrate, melt coating and solution coating can be mentioned, but solution coating is desirable in the process.
[0013]
In solution application, the film material is dissolved in a solvent at a predetermined ratio to prepare a solution having a predetermined concentration. As a solvent, although it varies depending on the type of film material to be used, usually hydrocarbons such as toluene, xylene, butylbenzene, tetrahydronaphthalene, decahydronaphthalene, ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol dimethyl ether, tetrahydrofuran, Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl lactate, ester such as γ-butyrolactone, N-methyl-2-pyrrolidone, dimethyl Amides such as formamide and dimethylacetamide, dichloromethane, carbon tetrachloride, tetrachloro Tan, a halogenated hydrocarbon such as chlorobenzene, butyl alcohol, triethylene glycol, diacetone alcohol, or an alcohol-based such as hexylene glycol. These solvents can be used by appropriately mixing two or more kinds as necessary. The concentration of the solution varies depending on the molecular weight and solubility of the polymer liquid crystal used, and finally the film thickness of the target film. However, it cannot be generally stated, but is usually 1 to 60% by weight, preferably 3 to 40%. % By weight.
[0014]
Further, a surfactant or the like may be added to the solution in order to facilitate application. Surfactants include, for example, cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides, polyamine derivatives, polyoxyethylene-polyoxypropylene condensates, primary or secondary alcohol ethoxylates. , Alkylphenol ethoxylates, polyethylene glycol and esters thereof, sodium lauryl sulfate, ammonium lauryl sulfate, amines of lauryl sulfate, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonic acid formalin condensates, etc. Surfactants, amphoteric surfactants such as laurylamidopropyl betaine, laurylaminoacetic acid betaine, non-ionic surfactants such as polyethylene glycol fatty acid esters, polyoxyethylene alkylamine, etc. Perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl group / hydrophilic group-containing oligomer, perfluoroalkyl / lipophilic group-containing oligomer par Fluorosurfactants such as fluoroalkyl group-containing urethane can be used. The addition amount of the surfactant depends on the kind of the surfactant, the solvent, or the supporting substrate to be applied, but is usually 10 ppm to 10%, preferably 50 ppm to 5% as a ratio to the weight of the polymer liquid crystal. Preferably it is 0.01 to 1% of range.
[0015]
The film material solution prepared as described above is applied onto an oriented support substrate. As the coating method, for example, a roll coating method, a die coating method, a bar coating method, a gravure roll coating method, a spray coating method, a dip coating method, a spin coating method, or the like can be employed.
[0016]
After coating, the solvent is removed by drying, and a cholesteric alignment is completed by heat treatment at a predetermined temperature and for a predetermined time to exhibit a cholesteric liquid crystal phase. Next, the cholesteric alignment film in which the cholesteric alignment is fixed can be obtained by rapidly cooling the cholesteric alignment formed in the liquid crystal state to a temperature below the glass transition point of the polymer liquid crystal.
[0017]
The thickness of the cholesteric alignment film is not particularly limited, but is usually 0.3 to 20 μm, preferably 0.5 to 10 μm, more preferably 0.7 to 3 μm from the viewpoint of mass productivity and manufacturing process. It is desirable to be. Further, the number of spiral turns of cholesteric orientation is usually 2 or more and 10 or less, preferably 2 or more and 6 or less. When the number of spiral turns is less than 2 turns or more than 10 turns, the effect as a polarization diffraction element may not be exhibited.
[0018]
The second step of the present invention is a step of transferring the diffraction pattern of the diffraction element substrate onto the cholesteric alignment film surface obtained in the first step. The material of the diffractive element substrate used when transferring the diffraction pattern to the cholesteric alignment film may be a material such as metal or resin, or a film having a diffractive function, or a diffractive function on the film. Any material may be used as long as it has a diffractive function, such as a transfer of a thin film including Among these, when considering ease of handling and mass productivity, a film or a film laminate having a diffraction function is more desirable.
[0019]
In addition, the term “diffraction element” as used herein includes, as its definition, all diffraction elements that generate diffracted light such as a flat hologram master. Also, the type may be a diffractive element derived from the surface shape, a so-called film thickness modulation hologram type, or a phase element that does not depend on the surface shape or the surface shape is converted into a refractive index distribution, so-called refraction. It may be a rate modulation hologram type. In the present invention, the type of film thickness modulation hologram is more preferably used because the diffraction pattern information of the diffraction element can be more easily imparted to the liquid crystal. Moreover, even if it is a type of refractive index modulation, if it has the undulation which produces diffraction on a surface shape, it can be used suitably for this invention.
[0020]
The conditions for transferring the diffraction pattern to the cholesteric alignment film vary depending on the physical properties of the cholesteric alignment film, the material of the diffractive element substrate, etc., but cannot generally be said, but the temperature is usually 40 to 300 ° C., preferably 70 to The heating and / or pressurizing conditions can be performed at 180 ° C. and pressure of 0.05 to 80 MPa, preferably 0.1 to 20 MPa. When the temperature is lower than 40 ° C., the transfer of the diffraction pattern may be insufficient in the cholesteric alignment film having a sufficiently stable alignment state at room temperature. Moreover, when it exceeds 300 degreeC, there exists a possibility that decomposition | disassembly and deterioration of a cholesteric alignment film may occur. On the other hand, when the pressure is lower than 0.05 MPa, the transfer of the diffraction pattern may be insufficient. Further, if it is higher than 80 MPa, the cholesteric alignment film or other base material may be destroyed, which is not desirable.
[0021]
Further, the time required for the transfer cannot be said unconditionally because it differs depending on the type of film material forming the cholesteric alignment film, the film form, the diffraction pattern type, the material of the diffraction element substrate, etc., but usually 0.01 seconds or more, Preferably it is 0.05 second-1 minute. When the processing time is shorter than 0.01 seconds, there is a possibility that the transfer of the diffraction pattern becomes insufficient. Also, a processing time exceeding 1 minute is not desirable from the viewpoint of productivity.
[0022]
As a specific method for transferring the diffraction pattern to the cholesteric alignment film, for example, a general compression molding machine, a rolling mill, a calender roller, a heat roller, a laminator, a hot stamp, an electric heating plate, a thermal head, etc. that satisfy the above-mentioned conditions are used. The diffraction pattern of the diffraction element substrate can be transferred to the cholesteric alignment film by using a molding machine or the like with the liquid crystal surface of the cholesteric alignment film in contact with the diffraction pattern surface. The transfer of the diffraction pattern is not limited to only one side of the cholesteric alignment film, and the diffraction pattern can be transferred to both sides of the cholesteric alignment film by the same method.
[0023]
After transferring the diffraction pattern of the diffraction element substrate to the cholesteric alignment film by the method and conditions as described above, the diffraction element substrate is removed from the cholesteric alignment film.
[0024]
The cholesteric alignment film from which the diffractive element substrate has been removed has a region exhibiting diffractive power on the film surface onto which the diffraction pattern has been transferred. Here, the region exhibiting diffractive power means a region that produces an effect such that light transmitted through the region or light reflected by the region wraps around a geometrically shadowed portion. The presence or absence of a diffractive area is confirmed by, for example, the presence or absence of light (high-order light) that is emitted at a certain angle in addition to light that is incident on the area and that is transmitted or reflected linearly (zero-order light). can do. As another method, it is possible to confirm whether or not a region exhibiting diffractive power is formed by observing the surface shape or cross-sectional shape of the liquid crystal layer with an atomic force microscope or a transmission electron microscope. Moreover, the area | region which shows diffraction power can also be formed in the multiple area | region of a cholesteric oriented film, for example, film front and back, respectively. Further, the region showing the diffractive power is not necessarily required to be formed as a layered state having a uniform thickness on the film surface, for example, and the region showing the diffractive power is formed on at least a part of the film surface. Thus, the effect as a polarization diffraction element can be exhibited. In addition, the region exhibiting diffractive power can be formed so as to have a shape such as a desired figure, pictograph, number or the like. Further, when a plurality of regions exhibiting diffractive power are provided, it is not necessary for all the regions to exhibit the same diffractive power, and the regions may exhibit different diffractive abilities.
[0025]
When the region exhibiting diffractive power is formed in a layered state, the thickness of the layer (region) exhibiting diffractive power is usually 50% or less, preferably 30% or less, preferably with respect to the film thickness of the cholesteric alignment film. Preferably, it is formed in a layer state having a thickness of 10% or less. If the thickness of the layer (region) exhibiting diffractive power exceeds 50%, the effects such as selective reflection characteristics and circular polarization characteristics due to the cholesteric liquid crystal phase are lowered, and the effect as a polarization diffraction element may not be obtained. There is.
[0026]
Furthermore, in the second step which is a constituent element of the present invention, the cholesteric alignment film to which the diffraction pattern of the diffraction element substrate has been transferred is the alignment state on the film surface to which the diffraction pattern is transferred, that is, the alignment state of the region exhibiting diffraction power However, the cholesteric orientation in which the spiral axis orientation is not uniformly parallel to the film thickness direction, preferably the spiral axis orientation is not uniformly parallel to the film thickness direction, and the spiral pitch is uniformly spaced in the film thickness direction. It is desirable to have no cholesteric orientation. In other regions, the same orientation state as the normal cholesteric orientation, that is, a spiral structure in which the spiral axis orientation is uniformly parallel to the film thickness direction and the spiral pitch is uniformly spaced in the film thickness direction. It is desirable to form.
[0027]
Moreover, in the cholesteric alignment film of the present invention, when the region exhibiting diffractive power has one film surface region, the front and back of the film, that is, the film surface having the region exhibiting diffractive power and the film surface opposite to the surface are It shows slightly different optical effects, color effects and the like. Therefore, it is desirable to select the arrangement position of the film surface of the cholesteric alignment film according to the application and the intended function.
[0028]
In the third step of the present invention, the diffraction pattern transfer surface of the cholesteric alignment film obtained after the transfer of the diffraction pattern obtained in the second step and the support substrate 1 are laminated via the adhesive layer 1. The support substrate 1 used in the third step is not particularly limited as long as it is a substrate having self-supporting properties such as a sheet-like material, a film-like material, and a plate-like material. In addition, when it is necessary to remove the support substrate 1 in the 6th process mentioned later, it is necessary to have removability with a shape and self-supporting property. As such a support substrate 1, a plastic film having usually peelability can be desirably used. Here, the removability means that the film can be peeled at the interface between the adhesive and the support substrate 1 in a state where the cholesteric alignment film and the support substrate 1 are bonded via the adhesive, and preferably supported via the adhesive. It is desirable that the air side surface of the cholesteric alignment film transferred to the substrate 1 and a support substrate 2 to be described later face each other through an adhesive and can be peeled off at the interface with the adhesive that directly contacts the support substrate 1. The above-mentioned support substrate 1 used in the third step of the present invention usually has a peel strength (180 ° peel test, peel rate of 30 cm / min) at the interface with the adhesive (after curing), usually 0. Those having a peel strength of 5 to 80 gf / 25 mm, preferably 2 to 50 gf / 25 mm are desirably used. Specific examples of the plastic film suitable as the support substrate 1 include olefin resins such as polyethylene, polypropylene, 4-methylpentene-1 resin, polyamide, polyimide, polyamideimide, polyetherimide, polyetherketone, Examples include polyether ether ketone, polyether sulfone, polyketone sulfide, polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyacetal, polycarbonate, polyvinyl alcohol, and cellulose-based plastics. These plastic films themselves may be used, or the surface of these plastic films coated with a silicone coating, organic thin film or inorganic thin film, chemical treatment to give appropriate removability Or those subjected to physical treatment can be used. As the support substrate 1 used in the third step of the present invention, polypropylene, polyetheretherketone, polyethylene terephthalate, polycarbonate, and a plastic film obtained by silicone-treating these film surfaces have an adhesive and appropriate adhesiveness and peelability. It is desirable because it has both.
[0029]
The adhesive layer 1 interposed between the cholesteric alignment film and the support substrate 1 is not particularly limited, and various conventionally known adhesives such as light or electron beam curable reactive adhesives are used. An agent, a hot-melt adhesive, or the like can be used as appropriate.
Examples of reactive adhesives include prepolymers and / or monomers having light or electron beam polymerizability, and other monofunctional, polyfunctional monomers, various polymers, stabilizers, photopolymerization initiators, and sensitizers as necessary. Etc. can be used.
[0030]
Specific examples of the prepolymer having light or electron beam polymerizability include polyester acrylate, polyester methacrylate, polyurethane acrylate, polyurethane methacrylate, epoxy acrylate, epoxy methacrylate, polyol acrylate, and polyol methacrylate. Examples of the monomer having light or electron beam polymerizability include monofunctional acrylate, monofunctional methacrylate, bifunctional acrylate, bifunctional methacrylate, trifunctional or higher polyfunctional acrylate, and polyfunctional methacrylate. Moreover, these can also use a commercial item, for example, using Aronix (acrylic special monomer, oligomer; made by Toagosei Co., Ltd.), light ester (made by Kyoeisha Chemical Co., Ltd.), biscoat (made by Osaka Organic Chemical Industry Co., Ltd.), etc. it can.
[0031]
Examples of photopolymerization initiators that can be used include benzophenone derivatives, acetophenone derivatives, benzoin derivatives, thioxanthones, Michler ketone, benzyl derivatives, triazine derivatives, acylphosphine oxides, and azo compounds.
[0032]
The viscosity of the light or electron beam curable reactive adhesive is appropriately selected depending on the processing temperature of the adhesive and cannot be generally specified, but is usually 10 to 2000 mPa · s at 25 ° C., preferably 50 to 1000 mPa. · S, more preferably 100 to 500 mPa · s. When the viscosity is lower than 10 mPa · s, it is difficult to obtain a desired thickness. Moreover, when higher than 2000 mPa * s, workability | operativity may fall and it is not desirable. When the viscosity is out of the above range, it is preferable to adjust the solvent and monomer ratio to a desired viscosity as appropriate.
[0033]
When a photo-curable reactive adhesive is used, a known curing means such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, or a xenon lamp can be used as a method for curing the adhesive. . The exposure amount varies depending on the type of the reactive adhesive to be used, so it cannot be generally stated, but usually 50 to 2000 mJ / cm. ² , Preferably 100 to 1000 mJ / cm ² It is.
[0034]
In addition, when an electron beam curable reactive adhesive is used, the method of curing the adhesive is appropriately selected according to the transmission power and curing power of the electron beam and cannot be generally specified. It can be cured by irradiation under a condition of a voltage of 50 to 1000 kV, preferably 100 to 500 kV.
[0035]
In addition, when a hot melt type adhesive is used as the adhesive, the adhesive is not particularly limited, but the hot melt working temperature is 80 to 200 ° C., preferably about 100 to 160 ° C. from the viewpoint of workability and the like. Desirably used. Specifically, polyvinyl acetal resins such as ethylene / vinyl acetate copolymer resins, polyester resins, polyurethane resins, polyamide resins, thermoplastic rubber resins, polyacrylic resins, polyvinyl alcohol resins, polyvinyl butyral, etc. , Petroleum resins, terpene resins, rosin resins and the like are used as base resins.
[0036]
Furthermore, the case where a pressure-sensitive adhesive is used as the adhesive is not particularly limited, and for example, a rubber-based, acrylic-based, silicone-based, or polyvinyl ether-based pressure-sensitive adhesive can be used.
The thickness of the adhesive varies depending on the application used and its workability, but cannot be generally specified, but is usually 0.5 to 50 μm, preferably 1 to 10 μm.
[0037]
Further, the method for forming the adhesive is not particularly limited. For example, a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, a gravure roll coating method, a spray coating method, a spin coating method. It can form on both the support substrate or the film surface to which the diffraction pattern of the cholesteric alignment film was transferred, or both the support substrate 1 and the cholesteric alignment film using a known method such as the method.
[0038]
In the adhesive layer 1 used in the third step, an ultraviolet light inhibitor and a hard coat agent can be blended. The ultraviolet absorber is not particularly limited as long as it is compatible or dispersible with the adhesive component as described above. For example, a benzophenone compound, a salicylate compound, a benzotriazole compound, an oxalic acid anilide compound, a cyanoacrylate compound. Organic ultraviolet absorbers such as compounds and inorganic ultraviolet absorbers such as cesium oxide, titanium oxide, and zinc oxide can be used. Of these, benzophenone compounds having high ultraviolet absorption efficiency are preferably used. Moreover, the ultraviolet absorber can be added individually by 1 type or in multiple types. Also, the hard coat agent is not particularly limited as long as it is compatible or dispersible with the adhesive component. For example, organopolysiloxane type, photocurable resin type acrylic oligomer type, urethane acrylate type, epoxy acrylate type, polyester An acrylate-based, thermosetting resin-based acrylic-silicon-based, or an inorganic compound such as ceramics can be used. Of these, organopolysiloxane-based and photo-curable resin-based acrylic oligomer-based hard coating agents are preferably used.
[0039]
The blending ratio of the ultraviolet absorber and / or hard coat agent in the adhesive layer 1 used in the third step varies depending on the adhesive component used, but is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight.
Furthermore, in the adhesive layer 1 used for adhesion between the cholesteric alignment film used in the third step and the support substrate 1, a light stabilizer such as a hindered amine or a quenching agent is necessary in addition to the ultraviolet absorber and the hard coat agent. Various additives such as an agent, an antistatic agent, a slipping improver, a dye, a pigment, a surfactant, and a filler such as fine silica and zirconia can also be blended. The mixing ratio of these various additives is not particularly limited as long as the effects of the present invention are not impaired, but is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight.
[0040]
The method of laminating the film surface on which the diffraction pattern of the cholesteric alignment film is transferred in the third step and the support substrate 1 through the adhesive layer 1 is not particularly limited. It can laminate | stack by selecting suitably from the various apparatuses illustrated by the method.
[0041]
Next, the alignment support substrate used in the first step as the fourth step is removed from the laminate configured in the order of the alignment support substrate / cholesteric alignment film / adhesive layer 1 / support substrate 1 obtained in the previous steps. Perform the process.
The method for removing the alignment support substrate from the cholesteric alignment film is not particularly limited, and examples thereof include a method of peeling off the alignment support substrate or dissolving the alignment support substrate. Examples of the peeling and removing method include, for example, a method in which an adhesive tape is applied to the corner end portion of the orientation support substrate to artificially peel off, a method in which mechanical peeling is performed using a roll, etc., after immersion in a poor solvent for all structural materials. A method of mechanically peeling, a method of peeling by applying ultrasonic waves in a poor solvent, a method of peeling by applying a temperature change using a difference in thermal expansion coefficient between an alignment support substrate and a cholesteric alignment film, an alignment support substrate Examples thereof include a method for dissolving and removing the alignment film on the alignment supporting substrate itself. Since the peelability varies depending on the physical properties of the film material forming the cholesteric alignment film and the adhesion to the alignment support substrate, a method most suitable for the system should be adopted.
[0042]
In this invention, after removing an orientation support substrate in a 4th process, the process of laminating | stacking the cholesteric orientation film surface which removed the orientation support substrate and the support substrate 2 through the adhesive layer 2 as a 5th process is performed. The supporting substrate 2 used in the fifth step is not particularly limited as long as it has a sheet-like material, a film-like material, a plate-like material, etc., for example, polyimide, polyamideimide, polyamide, polyether Imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyvinyl chloride, polystyrene, polypropylene, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, Sheets of polycarbonate, polyvinyl alcohol, polyacetal, polyarylate, cellulosic plastics, epoxy resin, phenol resin, etc. Beam or the substrate or paper, paper such as synthetic paper, metal foil, can be appropriately selected from a glass plate or the like. Moreover, as a support substrate, the unevenness | corrugation may be given to the surface.
[0043]
The adhesive layer 2 interposed between the cholesteric alignment film and the support substrate 2 is not particularly limited, and various conventionally known adhesives and adhesives described as the adhesive layer 1 in the third step, For example, a light or electron beam curable reactive adhesive, a hot melt adhesive, etc. are used as appropriate, for example, a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, a gravure roll coating method, It can be formed on the cholesteric alignment film surface from which the support substrate 2 or the alignment support substrate is removed or both the support substrate 2 and the cholesteric alignment film surface using a known method such as a spray coating method or a spin coating method.
[0044]
The present invention manufactures a polarization diffraction element constructed in the order of support substrate 2 / adhesive layer 2 / cholesteric alignment film / adhesive layer 1 / support substrate 1 through the first to fifth steps described above. be able to. Here, when the support substrate 1 used in the third step is a substrate that is not optically transparent, if the support substrate 1 exhibits undesirable optical characteristics in the intended application, the support substrate 1 serves as a polarization diffraction element. In the case where the effect disappears, or when a support substrate 1 having removability is used, the support substrate 1 used in the third step as the sixth step is removed from the cholesteric alignment film, and the support substrate is removed. The polarizing diffraction element comprised in order of 2 / adhesive layer 2 / cholesteric alignment film / adhesive layer 1 can be manufactured. Here, a function as a protective layer can be imparted to the adhesive layer 1 by blending an ultraviolet absorber and / or a hard coat agent into the adhesive layer 1 in the third step.
[0045]
The method for removing the support substrate 1 in the sixth step is, for example, a method of peeling and removing only the support substrate 1 or dissolving the support substrate 1 in the same manner as the method for removing the alignment support substrate in the fourth step. It is done. Examples of the peeling and removing method include, for example, a method in which an adhesive tape is applied to the corner end of the support substrate 1 to artificially peel off, a method in which mechanical peeling is performed using a roll or the like, and after immersion in a poor solvent for all structural materials. A method of mechanically peeling, a method of peeling by applying ultrasonic waves in a poor solvent, a method of peeling by giving a temperature change using a difference in thermal expansion coefficient between the support substrate 1 and the adhesive layer 1, a support substrate Examples thereof include a method for dissolving and removing 1 itself. About peelability, since it changes with various physical properties of the adhesive bond layer 1, and adhesiveness with the support substrate 1, the method most suitable for the system should be employ | adopted.
[0046]
The polarization diffraction element of the present invention thus obtained has a unique effect that diffracted light has circular polarization, which is not found in conventional optical members. Due to this effect, the use efficiency of light can be made extremely high by using it in a spectroscopic instrument that requires polarized light such as an ellipsometer. In a conventional spectroscopic optical device that requires polarized light, the light emitted from the light source is dispersed for each wavelength using a spectral element such as a diffraction grating or a prism, and then transmitted through the polarizer, or after being transmitted through the polarizer. A polarizer was essential. This polarizer absorbs about 50% of the incident light and has a problem that the light utilization efficiency is extremely poor due to reflection at the interface. However, the polarization obtained by the production method of the present invention The use efficiency of light is extremely high by using the diffraction element, and it is theoretically possible to use about 100%. Further, the polarization diffraction element obtained by the production method of the present invention can easily control the transmission and blocking of diffracted light by using a normal polarizing plate. Usually, diffracted light having no polarization cannot be completely blocked by any polarizing plate. That is, in the polarization diffraction element obtained by the manufacturing method of the present invention, for example, diffracted light having right polarization can be completely blocked only when the left circularly polarizing plate is used, and other polarizing plates can be used. It is not possible to achieve complete interruption. Because of this effect, for example, in an environment where the observer observes the diffraction image through the polarizing plate, the diffraction image suddenly emerges from the dark field or disappears suddenly by changing the state of the polarizing plate. It becomes possible to do.
[0047]
As described above, the polarization diffraction element obtained by the production method of the present invention has a very wide application range as a new diffraction function element, and is used as various optical elements, optoelectronic elements, decorative members, anti-counterfeiting elements, etc. can do.
[0048]
Specifically, as an optical element or an optoelectronic element, for example, a transparent and isotropic film, for example, a triacetyl cellulose film such as Fujitac (Fuji Photo Film Co., Ltd.), Konicatak (Konica Inc.), or a TPX film (Mitsui Chemicals). ), Arton film (manufactured by Nippon Synthetic Rubber Co., Ltd.), Zeonex film (manufactured by Nippon Zeon Co., Ltd.), acrylprene film (manufactured by Mitsubishi Rayon Co., Ltd.), etc. Development for various optical applications. For example, the polarization diffraction element may be TN (twisted nematic) -LCD (Liquid Crystal Display), STN (Super Twisted Nematic) -LCD, ECB (Electrically Controlled Birefringence), LCD (Electrically Controlled Birefringence), LCD. Various LCDs with improved color compensation and / or improved viewing angle can be obtained by providing for liquid crystal displays such as Birefringence (LCD), HAN (Hybrid Aligned Nematic) -LCD, IPS (In Plane Switching) -LCD. In addition, the polarization diffraction element can be used as a spectroscopic optical device that requires the polarized light separated as described above, a polarization optical element that obtains a specific wavelength by a diffraction phenomenon, an optical filter, a circularly polarizing plate, a light diffusion plate, and the like. In addition, it is possible to provide a variety of optical members that can exhibit an optical effect that is unprecedented as an optical element or an optoelectronic element, such as being able to obtain a linearly polarizing plate by combining with a quarter wavelength plate. .
[0049]
As a decorative member, various designable molding materials such as a new designable film having both a rainbow-colored coloring effect by diffractive power and a colorful coloring effect by cholesteric liquid crystal can be obtained. In addition, since it can be made thin, it can be expected to greatly contribute to differentiation from other similar products by attaching or integrating with existing products. For example, by attaching a polarization diffraction element incorporating a design diffraction pattern to a glass window or the like, or using a glass window or the like as a support substrate in the third step, the diffraction pattern is accompanied by the viewing angle from the outside. The selective reflection peculiar to cholesteric liquid crystals looks different colors and is excellent in fashion. Moreover, it is difficult to see the inside from a bright outside, and it is nevertheless possible to make a window with good external visibility from the inside.
[0050]
As an anti-counterfeiting element, it can be used as a new anti-counterfeiting film, a seal, a label or the like having both the anti-counterfeiting effects of the diffraction element and the cholesteric liquid crystal. Specifically, as the support substrate in the third step of the present invention, for example, an automobile driver's license, an identification card, a passport, a credit card, a prepaid card, various cash vouchers, a gift card, a card substrate for securities, a mount, etc. are used. Accordingly, the polarization diffraction element can be integrated with a card substrate, a mount, or the like, or provided on a part, specifically, pasted, embedded, or woven into paper. The polarizing diffraction element obtained by the production method of the present invention has a region exhibiting diffractive power on the surface of the cholesteric alignment film, and the film surface is covered with an adhesive layer, and further, wavelength selective reflection of cholesteric liquid crystal. , Circularly polarized light selective reflectivity, color viewing angle dependency, and beautiful cholesteric color. Therefore, when the polarizing diffraction element obtained by the production method of the present invention is used as an anti-counterfeiting element, it is difficult to forge the polarizing diffraction element, and more specifically, a region exhibiting diffractive power is formed on the film surface. It can be said that forgery of the cholesteric alignment film is extremely difficult. In addition to the anti-counterfeiting effect, the rainbow-colored coloring effect of the diffractive element and the colorful coloring effect of the cholesteric liquid crystal have excellent design properties. For these reasons, the polarization diffraction element obtained by the production method of the present invention is very suitable as an anti-counterfeiting element.
[0051]
These uses are only examples, and the polarization diffraction element obtained by the manufacturing method of the present invention has been conventionally used in various applications in which a single diffractive element, a cholesteric alignment film with a fixed normal cholesteric orientation is used, and new applications. Therefore, it can be applied to various uses other than the above-mentioned uses.
[0052]
【Example】
Examples will be described below, but the present invention is not limited thereto.
Various measurement methods used in the present invention will be described.
[0053]
(GPC measurement method)
Tosoh GPC (CP8000, CO8000, UV8000) was connected to a column having a structure of TSKG3000HXL, G2000HXL, G1000HXL, and measurement was performed at 25 ° C. with a tetrahydrofuran (THF) solvent at a flow rate of 0.7 ml / min. A calibration curve was separately prepared using standard polystyrene under the same conditions, and the weight average molecular weight Mw, number average molecular weight Mn, and molecular weight distribution Mw / Mn in terms of polystyrene were determined.
(Measurement of glass transition temperature (Tg))
Measurement was performed with a DSC990 manufactured by Du Pont.
(Measurement of transition temperature (Ti) from liquid crystal phase to isotropic phase)
The measurement was carried out with a polarizing microscope BX50 manufactured by Olympus Corp. equipped with a hot stage.
[0054]
Example 1
On a polyphenylene sulfide film having a rubbing treatment of a liquid crystalline polyester (containing an R-form optically active compound) having Mw of 3000, Mw / Mn of 2.0, logarithmic viscosity of 0.124 dl / g, Tg of 80 ° C., and Ti of 230 ° C. A film was formed by spin coating. Subsequently, when heat-treated at 180 ° C. for 5 minutes, a film exhibiting a gold specular reflection was obtained.
When the transmission spectrum of the obtained film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, it showed selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a cholesteric alignment film having a fixed cholesteric alignment was obtained.
[0055]
Next, the diffracting surface of the engraved diffraction grating film (900 lines / mm) manufactured by Edmund Scientific Japan Co., Ltd. and the liquid crystal surface of the cholesteric liquid crystal film face each other, and a laminator DX-350 manufactured by Tokyo Laminex Co. is used. Heating and pressing were performed under the conditions of ° C, 0.3 MPa, and roll contact time of 0.5 seconds. After cooling to room temperature, the diffraction grating film was removed.
When the surface of the cholesteric alignment film on which the diffraction grating film was overlaid was observed, iridescent colors resulting from the diffraction pattern and selective reflection specific to the cholesteric liquid crystal were clearly recognized. In addition, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed with a polarizing microscope and a transmission electron microscope with a cross section of the liquid crystal layer, the spiral axis direction in the cholesteric phase was not uniformly parallel to the film thickness direction. In addition, it was confirmed that cholesteric alignment in which the helical pitch is not uniformly spaced in the film thickness direction is formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that the cholesteric orientation in which the spiral axis direction is uniformly parallel to the film thickness direction and the spiral pitch is uniformly spaced in the film thickness direction is formed. The number of spiral turns of cholesteric orientation in this region was 3. Further, when a He—Ne laser (wavelength 632.8 nm) was incident perpendicularly into the plane of the cholesteric alignment film, laser light was observed at an emission angle of 0 ° and about ± 35 °. Furthermore, in order to confirm the polarization characteristics, when the film obtained under normal indoor lighting was placed and observed through a right circularly polarizing plate (transmitting only the right circularly polarized light), iridescent reflected diffracted light was observed, It was almost the same as the brightness when observed without a polarizing plate. On the other hand, when observed through the left circularly polarizing plate (only the left circularly polarized light was transmitted), it became a dark field and no iridescent reflected diffracted light was observed. From these facts, in the cholesteric alignment film, it was confirmed that a region exhibiting diffractive power was formed in the film surface region, and that the diffracted light was right circularly polarized light.
[0056]
Dilute the trial UV curable adhesive (Aronix UV-3630 manufactured by Toagosei Co., Ltd. with N-vinyl-2-pyrrolidone so that the viscosity is 100 mPa · s on the surface of the cholesteric alignment film on which the diffraction pattern is transferred. ; Adhesive layer 1) is applied with a bar coater to a thickness of 5 μm, and a triacetyl cellulose film (supporting substrate 1) is laminated thereon with a laminator and cured by UV irradiation. The polyphenylene sulfide film used as the alignment support substrate was held by hand, and the polyphenylene sulfide film was peeled off at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer in the 180 ° direction. Next, the above-mentioned trial UV curable adhesive (becomes the adhesive layer 2) is applied to the cholesteric liquid crystal layer surface with a bar coater so as to have a thickness of 5 μm, and a triacetyl cellulose film (becomes the support substrate 2) thereon. Were laminated with a laminator and cured by irradiation with ultraviolet rays to obtain a polarization diffraction element. The alignment state of the cholesteric alignment film portion of the obtained polarization diffraction element was not different from the above-mentioned various observations.
[0057]
(Example 2)
Spin on polyphenylene sulfide with rubbing treatment of liquid crystalline polyester (containing R-form optically active compound) with Mw of 7000, Mw / Mn of 2.0, logarithmic viscosity of 0.144 dl / g, Tg of 85 ° C. and Ti of 230 ° C. A film was formed by a coating method. Subsequently, when heat-treated at 200 ° C. for 5 minutes, a film exhibiting a golden specular reflection was obtained. When the transmission spectrum of the obtained film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, it showed selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a film having a fixed cholesteric orientation was formed.
[0058]
The laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. is laminated so that the diffraction surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Was used and heated and pressurized under the conditions of 120 ° C., 0.3 MPa, and roll contact time of 0.5 seconds. After cooling to room temperature, the engraved diffraction grating film was removed.
[0059]
When the surface of the cholesteric alignment film on which the diffraction grating film was overlaid was observed, iridescent colors resulting from the diffraction pattern and selective reflection specific to the cholesteric liquid crystal were clearly recognized. In addition, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed with a polarizing microscope and a transmission electron microscope with a cross section of the liquid crystal layer, the spiral axis direction in the cholesteric phase was not uniformly parallel to the film thickness direction. In addition, it was confirmed that cholesteric alignment in which the helical pitch is not uniformly spaced in the film thickness direction is formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that the cholesteric orientation in which the spiral axis direction is uniformly parallel to the film thickness direction and the spiral pitch is uniformly spaced in the film thickness direction is formed. The number of spiral turns of cholesteric orientation in this region was 5. Further, when a He—Ne laser (wavelength 632.8 nm) was incident perpendicularly into the plane of the cholesteric alignment film, laser light was observed at an emission angle of 0 ° and about ± 35 °. Furthermore, in order to confirm the polarization characteristics, a cholesteric alignment film obtained under normal room illumination was placed and observed through a right circularly polarizing plate (only the right circularly polarized light was transmitted). It was almost the same as the brightness when observed without a polarizing plate. On the other hand, when observed through the left circularly polarizing plate (only the left circularly polarized light was transmitted), it became a dark field and no iridescent reflected diffracted light was observed. From these facts, in the cholesteric alignment film, it was confirmed that a region exhibiting diffractive power was formed in the film surface region, and that the diffracted light was right circularly polarized light.
[0060]
Next, on the surface on which the diffraction pattern of the cholesteric alignment film is transferred, 5 wt. Of fine silica (Nippon Aerosil, Aerosil R812 (trade name)) is added to Lipoxy SP-1509 (trade name made by Showa Polymer) using a bar coater. %, A 20 wt% solution of isopropyl alcohol (adhesive layer 1) mixed with 5 wt% of UV absorber CyasorbUV-24 (manufactured by Cytec) and 4 wt% of lucillin TPO (trade name of BASF) with a bar coater After coating and drying to a thickness of 5 μm, a polyethylene terephthalate film (support substrate 1) is bonded to the coated surface using a table laminator, irradiated with ultraviolet rays to cure the adhesive, and then polyphenylene used as an orientation support substrate Hold the end of the sulfide film by hand, and polyphenylenesulfur in the 180 ° direction. The film was peeled off at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer. Further, a commercially available acrylic photo-curing adhesive (adhesive layer 2) was applied to the exposed cholesteric liquid crystal layer surface with a bar coater to a thickness of 5 μm, and a triacetyl cellulose film (supporting substrate 2) was applied thereon. After laminating with a laminator, the film was cured by irradiation with ultraviolet rays, and then the polyethylene terephthalate film was peeled off in the 180 ° direction to obtain a polarization diffraction element.
[0061]
The alignment state of the cholesteric alignment film portion of the obtained polarization diffraction element was not different from the above-mentioned various observations.
[0062]
(Example 3)
Spin on polyphenylene sulfide with rubbing treatment of liquid crystalline polyester (containing R-form optically active compound) with Mw of 7000, Mw / Mn of 2.0, logarithmic viscosity of 0.144 dl / g, Tg of 85 ° C. and Ti of 230 ° C. A film was formed by a coating method. Subsequently, when heat-treated at 200 ° C. for 5 minutes, a film exhibiting a golden specular reflection was obtained. When the transmission spectrum of the obtained film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, it showed selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a film having a fixed cholesteric orientation was formed.
[0063]
Laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. is laminated so that the diffraction surface of the engraved diffraction element film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Was used and heated and pressurized under the conditions of 120 ° C., 0.1 MPa, and roll contact time of 0.5 seconds. After cooling to room temperature, the engraved diffraction grating film was removed.
[0064]
When the surface of the cholesteric alignment film on which the diffraction grating film was overlaid was observed, iridescent colors resulting from the diffraction pattern and selective reflection specific to the cholesteric liquid crystal were clearly recognized. In addition, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed with a polarizing microscope and a transmission electron microscope with a cross section of the liquid crystal layer, the spiral axis direction in the cholesteric phase was not uniformly parallel to the film thickness direction. In addition, it was confirmed that cholesteric alignment in which the helical pitch is not uniformly spaced in the film thickness direction is formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that the cholesteric orientation in which the spiral axis direction is uniformly parallel to the film thickness direction and the spiral pitch is uniformly spaced in the film thickness direction is formed. Further, when a He—Ne laser (wavelength 632.8 nm) was incident perpendicularly into the plane of the cholesteric alignment film, laser light was observed at an emission angle of 0 ° and about ± 35 °. Furthermore, in order to confirm the polarization characteristics, when the film obtained under normal indoor lighting was placed and observed through a right circularly polarizing plate (transmitting only the right circularly polarized light), iridescent reflected diffracted light was observed, It was almost the same as the brightness when observed without a polarizing plate. On the other hand, when observed through the left circularly polarizing plate (only the left circularly polarized light was transmitted), it became a dark field and no iridescent reflected diffracted light was observed. From these facts, in the cholesteric alignment film, it was confirmed that a region exhibiting diffractive power was formed in the film surface region, and that the diffracted light was right circularly polarized light.
[0065]
A commercially available adhesive made of a photocurable acrylic oligomer was applied to the cholesteric liquid crystal surface of the obtained cholesteric alignment film using a bar coater so as to have a thickness of 5 μm. Next, a triacetyl cellulose film is bonded to the coated surface using a table laminator, irradiated with ultraviolet rays, and the adhesive is cured, and then the end of the polyphenylene sulfide film used as an orientation support substrate is held by hand, and the 180 ° direction The polyphenylene sulfide film was peeled off at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer. Next, the above-mentioned commercially available acrylic photo-curing adhesive is applied to the surface of the cholesteric liquid crystal layer with a bar coater to a thickness of 5 μm, and a triacetyl cellulose film is laminated thereon with a laminator and cured by irradiation with ultraviolet rays. Thus, a polarization diffraction element was obtained. The alignment state of the cholesteric alignment film portion of the obtained polarization diffraction element was not different from the above-mentioned various observations.
[0066]
(Example 4)
Spin on polyphenylene sulfide with a rubbing treatment of a liquid crystalline polyester (containing R-type optically active compound) with Mw of 20000, Mw / Mn2.2, logarithmic viscosity of 0.344 dl / g, Tg of 102 ° C, and Ti of 250 ° C. A film was formed by a coating method. Subsequently, when heat-treated at 220 ° C. for 5 minutes, a film exhibiting a golden specular reflection was obtained. When the transmission spectrum of the obtained film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, it showed selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a film having a fixed cholesteric orientation was formed.
[0067]
The diffraction surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan Co., Ltd. and the liquid crystal surface of the cholesteric alignment film obtained above are stacked so as to face each other. After heating and pressurizing for 30 seconds, cooling with water and cooling to room temperature, the engraved diffraction grating film was removed.
[0068]
When the surface of the cholesteric alignment film on which the diffraction grating film was overlaid was observed, iridescent colors resulting from the diffraction pattern and selective reflection specific to the cholesteric liquid crystal were clearly recognized. In addition, when the orientation state of the cholesteric alignment film surface from which the diffraction grating film was removed was observed with a polarizing microscope and a transmission electron microscope with a cross section of the liquid crystal layer, the spiral axis direction in the cholesteric phase was not uniformly parallel to the film thickness direction. In addition, it was confirmed that cholesteric alignment in which the helical pitch is not uniformly spaced in the film thickness direction is formed in the surface region of the liquid crystal layer. In other regions, it was confirmed that the cholesteric orientation in which the spiral axis direction is uniformly parallel to the film thickness direction and the spiral pitch is uniformly spaced in the film thickness direction is formed. The number of spiral turns of cholesteric orientation in this region was 6. Further, when a He—Ne laser (wavelength 632.8 nm) was incident perpendicularly into the plane of the cholesteric alignment film, laser light was observed at an emission angle of 0 ° and about ± 35 °. Furthermore, in order to confirm the polarization characteristics, when the film obtained under normal indoor lighting was placed and observed through a right circularly polarizing plate (transmitting only the right circularly polarized light), iridescent reflected diffracted light was observed, It was almost the same as the brightness when observed without a polarizing plate. On the other hand, when observed through the left circularly polarizing plate (only the left circularly polarized light was transmitted), it became a dark field and no iridescent reflected diffracted light was observed. From these facts, in the cholesteric alignment film, it was confirmed that a region exhibiting diffractive power was formed in the film surface region, and that the diffracted light was right circularly polarized light.
[0069]
Using a bar coater on the cholesteric liquid crystal surface having the diffractive power of the obtained cholesteric alignment film, the trial UV curable adhesive used in Example 1 was applied to a thickness of 5 μm with the bar coater, A triacetyl cellulose film is bonded to the coated surface using a desktop laminator, irradiated with ultraviolet rays, and the adhesive is cured. Then, the end of the polyphenylene sulfide film used as an orientation support substrate is held by hand, and the polyphenylene is oriented in the 180 ° direction. The sulfide film was peeled off at the interface between the polyphenylene sulfide film and the cholesteric liquid crystal layer.
[0070]
Next, the cholesteric liquid crystal layer from which the polyphenylene sulfide film has been peeled is bonded to the acrylate resin (trade name, manufactured by Mitsubishi Rayon) via the UV curable adhesive, using a table laminator, and irradiated with ultraviolet rays to cure the adhesive. Thus, a polarization diffraction element was obtained. The alignment state of the cholesteric alignment film portion of the obtained polarization diffraction element was not different from the above-mentioned various observations.
[0071]
(Comparative Example 1)
Spin coating method on polyphenylene sulfide obtained by rubbing liquid crystalline polyester (containing R-form optically active compound) having Mw of 950, Mw / Mn2, logarithmic viscosity of 0.06 dl / g, Tg of 60 ° C. and Ti of 220 ° C. To form a film. Subsequently, when heat-treated at 180 ° C. for 5 minutes, a film exhibiting a gold specular reflection was obtained. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, a cholesteric alignment showing selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a film in which was fixed was formed.
[0072]
Laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. is laminated so that the diffraction surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Was used and heated and pressurized under the conditions of 120 ° C., 0.3 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction grating film was removed.
In the obtained film, cracks occurred in a part of the film, and the cholesteric alignment was disturbed, resulting in uneven alignment. In addition, no rainbow color due to the diffraction pattern was exhibited.
[0073]
(Comparative Example 2)
Liquid crystalline polyester having an Mw (weight average molecular weight) of about 120,000, an Mw / Mn of 4.0, a logarithmic viscosity of 2.0 dl / g, a Tg of 150 ° C., and a Ti of 240 ° C. (containing an R-form optically active compound) Was rubbed onto a polyphenylene sulfide by spin coating and heat treated at 220 ° C. for 20 minutes to obtain a pale yellow film showing weak selective reflection. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm, and the selective reflection wavelength band was broad. It showed a weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, many alignment defects were observed in the liquid crystal layer.
[0074]
Next, the diffracting surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan Co., Ltd. and the liquid crystal surface of the film obtained above are stacked so that the laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. It was used and heated and pressurized under the conditions of 120 ° C., 0.05 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction grating film was removed. The liquid crystal surface from which the diffraction grating film was removed had more alignment defects, and did not exhibit any iridescence due to the diffraction pattern.
[0075]
(Comparative Example 3)
On a polyphenylene sulfide obtained by rubbing a liquid crystalline polyester (containing an R-form optically active compound) having an Mw of 95,000, an Mw / Mn of 6.0, a logarithmic viscosity of 1.5 dl / g, a Tg of 145 ° C., and a Ti of 240 ° C. When a film was formed by spin coating and heat-treated at 220 ° C. for 20 minutes, a pale yellow film showing weak selective reflection was obtained. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm, and the selective reflection wavelength band was broad. It showed a weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, many alignment defects were observed in the liquid crystal layer.
[0076]
Next, the diffracting surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan Co., Ltd. and the liquid crystal surface of the film obtained above are stacked so that the laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. It was used and heated and pressurized under the conditions of 120 ° C., 0.05 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction grating film was removed. The liquid crystal surface from which the diffraction grating film was removed had more alignment defects, and did not exhibit any iridescence due to the diffraction pattern.
[0077]
(Comparative Example 4)
On a polyphenylene sulfide obtained by rubbing a liquid crystalline polyester (containing an R-form optically active compound) having an Mw of 98000, an Mw / Mn of 3.0, a logarithmic viscosity of 1.8 dl / g, a Tg of 205 ° C., and a Ti of 250 ° C. When a film was formed by spin coating and heat-treated at 230 ° C. for 20 minutes, a pale yellow film showing weak selective reflection was obtained. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm, and the selective reflection wavelength band was broad. It showed a weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, many alignment defects were observed in the liquid crystal layer.
[0078]
Next, the Laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. was placed so that the diffraction surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the film obtained above face each other. It was used and heated and pressurized under the conditions of 120 ° C., 3 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction grating film was removed. The liquid crystal surface from which the diffraction grating film was removed had more alignment defects, and did not exhibit any iridescence due to the diffraction pattern.
[0079]
(Comparative Example 5)
Rubbing liquid crystalline polyester (containing R-form optically active compound) with Mw (weight average molecular weight) of 1040, Mw / Mn of 2.1, logarithmic viscosity of 0.06 dl / g, Tg of 15 ° C, and Ti of 36 ° C When a film was formed on the treated polyphenylene sulfide by a spin coating method and heat-treated at 30 ° C. for 5 minutes, a film exhibiting a golden mirror reflection was obtained. When the transmission spectrum of this film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, a cholesteric liquid crystal exhibiting selective reflection having a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a layer was formed.
[0080]
Laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. is laminated so that the diffraction surface of the engraved diffraction element film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the cholesteric alignment film obtained above face each other. Was used and heated and pressurized under the conditions of 40 ° C., 0.05 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction element film was removed.
In the obtained film, a part of the cholesteric liquid crystal phase was transferred to the isotropic phase, and the cholesteric alignment was disturbed, resulting in alignment unevenness. In addition, no rainbow color due to the diffraction pattern was exhibited.
[0081]
(Comparative Example 6)
Rubbing liquid crystalline polyester (containing R-form optically active compound) having Mw (weight average molecular weight) of 1030, Mw / Mn of 2.2, logarithmic viscosity of 0.046 dl / g, Tg of 20 ° C. and Ti of 115 ° C. When a film was formed on the treated polyphenylene sulfide by a spin coating method and heat-treated at 100 ° C. for 5 minutes, a film exhibiting golden specular reflection was obtained. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, a cholesteric alignment showing selective reflection with a center wavelength of about 600 nm and a selective reflection wavelength bandwidth of about 100 nm. It was confirmed that a film in which was fixed was formed.
[0082]
The diffractive surface of the engraved diffraction element film (900 pieces / mm) manufactured by Edmund Scientific Japan Co., Ltd. and the liquid crystal surface of the cholesteric alignment film obtained above are stacked so as to face each other. , 80 MPa, and pressurization time was 30 seconds. Next, after cooling to room temperature, the engraved diffraction element film was removed. In the obtained film, cracks occurred in a part of the film, and the cholesteric alignment was disturbed, resulting in uneven alignment. In addition, no rainbow color due to the diffraction pattern was exhibited.
[0083]
(Comparative Example 7)
On a polyphenylene sulfide obtained by rubbing a liquid crystalline polyester (containing an R-type optically active compound) having a Mw of 98900, Mw / Mn of 4.0, logarithmic viscosity of 2.5 dl / g, Tg of 148 ° C., and Ti of 250 ° C. When a film was formed by spin coating and heat-treated at 220 ° C. for 20 minutes, a pale yellow film showing weak selective reflection was obtained. When the transmission spectrum of the film was measured with an ultraviolet-visible near-infrared spectrophotometer V-570 manufactured by JASCO Corporation, the center wavelength was not clearly specified at about 550 to 600 nm, and the selective reflection wavelength band was broad. It showed a weak selective reflection. When observed with a microscope BX50 manufactured by Olympus Corporation, many alignment defects were observed in the liquid crystal layer, and uniform cholesteric alignment was not obtained.
Next, the Laminator DX-350 manufactured by Tokyo Laminex Co., Ltd. was placed so that the diffraction surface of the engraved diffraction grating film (900 pieces / mm) manufactured by Edmund Scientific Japan and the liquid crystal surface of the film obtained above face each other. It was used and heated and pressurized under the conditions of 120 ° C., 3 MPa, and roll contact time of 0.5 seconds. Next, after cooling to room temperature, the engraved diffraction grating film was removed. The liquid crystal surface from which the diffraction grating film was removed had more alignment defects, and did not exhibit any iridescence due to the diffraction pattern.
[0084]
【The invention's effect】
In the present invention, by using a polymer liquid crystal having specific physical properties as a film material, the diffraction pattern of the diffractive element substrate can be easily aligned with the cholesteric alignment film obtained from the material without performing complicated processes or treatments. Can be transferred. As a result, it is possible to manufacture a polarization diffractive element having unique optical characteristics such that diffracted light not shown in the conventional optical element has circular polarization. Moreover, since the cholesteric alignment film surface to which the diffraction pattern is transferred is in contact with the outermost adhesive layer, the polarization diffraction element obtained by the production method of the present invention can express the diffraction effect more remarkably.
[0085]
Moreover, since it has such optical characteristics, the polarizing diffraction element obtained by the production method of the present invention has a very wide application range as a diffraction function element, for example, an optical element such as a liquid crystal display, an optoelectronic element, and a decoration material. It can be suitably used as an optical member such as an anti-counterfeiting element.

Claims (2)

The weight average molecular weight Mw measured by GPC (polystyrene conversion) on the orientation support substrate is 1,000 to 100,000, the molecular weight distribution (Mw / Mn; Mn is the number average molecular weight) is 5 or less, and the logarithmic viscosity is 0.05 to 2.0. (Concentration 0.5 g / dl (temperature 30 ° C.) in a mixed solvent of phenol / tetrachloroethane (weight ratio 60/40)), glass transition temperature (Tg) 200 ° C. or less, and transition temperature from liquid crystal phase to isotropic phase The first step of forming a cholesteric alignment film made of liquid crystalline polyester having (Ti) of 40 ° C. or higher, the second step of transferring the diffraction pattern of the diffraction element substrate to the surface of the cholesteric alignment film, and the cholesteric alignment in which the diffraction pattern is transferred The third step of laminating the film surface and the support substrate 1 via the adhesive layer 1 and the orientation support substrate used in the first step are cholesteric. Fourth step and fifth step method for producing a polarization diffraction element comprising, for laminated through an adhesive layer 2 of cholesteric orientation film surface removing the alignment supporting substrate and the supporting substrate 2 to be removed from oriented film. After a cholesteric orientation film surface removing the alignment supporting substrate and the supporting substrate 2 are laminated via an adhesive layer, according to claim 1 comprising a sixth step of removing the supporting substrate 1 used in the third step from the cholesteric alignment film serial mounting method for manufacturing a polarization diffraction element.