JP2023164856A - Partial optical rotator and partial optical rotation film using the same, intermediate film laminate, functional glass, and head-up display - Google Patents

Abstract

To provide a partial optical rotator capable of suppressing generation of double reflection in an image display region and achieving a windshield having good appearance in which a boundary line between the image display region and other region is hardly recognized, and a partial optical rotation film using the same, an intermediate film laminate, a functional glass, and a head-up display.SOLUTION: A partial optical rotator includes at least one layer of a liquid crystal layer including a first region that expresses optical rotation and a second region that expresses no optical rotation with respect to a normal direction. The first region and the second region are present in the same liquid crystal layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a partial optical rotator suitable for use in, for example, a head-up display, as well as a partial optical rotator film, an interlayer film laminate, a functional glass, and a head-up display using the same.

2. Description of the Related Art Navigation systems, head-up displays (hereinafter also referred to as "HUD"), and the like are used as methods for displaying information to drivers of automobiles, airplanes, and the like. A HUD is a system that projects an image projected from an image display means such as a liquid crystal display (hereinafter referred to as "LCD") onto, for example, a windshield of an automobile.

Display light emitted from the image display means is reflected by a reflecting mirror, further reflected by a windshield, and then reaches the viewer. The viewer sees the displayed image projected onto the windshield, but the displayed image appears to be a virtual image located further away than the windshield. With this method, the driver can obtain a variety of information without having to move his/her line of sight while keeping his/her gaze fixed on the front of the windshield, making it safer than traditional car navigation systems that require the driver to move his or her line of sight. be.

Windshields are usually constructed as laminated glass. The projected image reflected on the windshield is reflected and displayed on each of the glass on the viewer's side inside the vehicle and the glass on the outside of the vehicle, resulting in a double image in which the two reflected projected images overlap. Such a phenomenon is called a ghost phenomenon, and significantly reduces image visibility for an observer. Various countermeasures have been considered for this problem.

Patent Document 1 discloses a technique that uses a wedge-shaped interlayer film to make the reflected image of the glass on the viewer's side match the reflected image of the glass on the outside of the vehicle, thereby suppressing the occurrence of double images. Furthermore, in Patent Document 2 and Patent Document 3, an optical rotator made of a 1/2 wavelength film or a twisted nematic liquid crystal is placed in a laminated glass, and the projected image is S-polarized and incident at the Brewster angle. A technique has been disclosed that eliminates reflections on the outside glass and projects images only on the glass on the viewer's side to suppress the occurrence of double images. Furthermore, in Patent Document 4, a light control film that combines a quarter-wave plate and a light reflection layer made of cholesteric liquid crystal is placed inside a laminated glass, and a projected image of P-polarized light is projected onto this light control film by Brewster. A technique has been disclosed for suppressing the occurrence of double images by making the light incident at an angle.

Patent No. 2815693 Japanese Unexamined Patent Publication No. 2-141720 Patent No. 2958418 Patent No. 5973109

Sunglasses are sometimes used to reduce glare caused by light reflected from road surfaces and the like. Generally, light reflected from a road surface has the property of becoming polarized light, so it is effective to use polarized sunglasses to protect against this reflected light. On the other hand, for example, with the technologies disclosed in Patent Documents 2 and 3, although the occurrence of double images is suppressed, the S-polarized light reflected from the road surface becomes P-polarized light when it enters the car through the windshield. It will be converted. Polarized sunglasses have a polarizer arranged to absorb S-polarized light reflected from the road surface, so even if you use polarized sunglasses while driving during the day, you will not be able to obtain a light blocking effect. Therefore, when using the techniques disclosed in Patent Documents 2 and 3, it is necessary to arrange an optical rotator made of a 1/2 wavelength plate or twisted nematic liquid crystal only in the image projection area, not on the entire surface of the windshield. Ta. However, in an actual windshield, if these optical rotators are placed only in the image projection area, the boundary line of the area where the optical rotators are placed can be easily seen with the naked eye, resulting in a poor appearance. was there.

The present invention provides a partial optical rotator that suppresses the occurrence of double reflection in an image display area and makes it possible to realize a windshield with a good appearance in which the border line between the image display area and other areas is difficult to see; The object of the present invention is to provide a partial optical rotation film, an interlayer film laminate, a functional glass, and a head-up display using the same.

As a result of intensive studies to solve the above problems, the inventors of the present invention have devised a structure in which a region that exhibits optical rotation and a region that does not exhibit optical rotation in the normal direction are formed as one seamless layer. A new discovery has been made that by reducing the visibility of the boundary line between the image display area and the image non-display area, it is possible to significantly improve the appearance of the windshield while suppressing the occurrence of double images in the image display area. This led to the completion of the present invention.

That is, the present invention relates to [1] to [9].
[1] At least one liquid crystal layer including a first region that exhibits optical rotation and a second region that does not exhibit optical rotation in the normal direction,
A partial optical rotator, wherein the first region and the second region are present in the same liquid crystal layer.
[2] The partial optical rotator according to [1], wherein the liquid crystal layer is a liquid crystal alignment layer formed from a composition for forming a liquid crystal layer containing a polymerizable liquid crystal monomer or a liquid crystal polymer.
[3] The partial optical rotator according to [1] or [2], wherein the first region is a half-wave plate or a twisted nematic liquid crystal layer.
[4] The partial optical rotator according to any one of [1] to [3], wherein the first region provides a phase difference of 0.8π or more and 1.2π or less to the polarization plane of the incident light.
[5] Plastic film and
A partial optical rotation film comprising: the partial optical rotator according to any one of [1] to [4] formed on the plastic film.
[6] The partial optical rotator according to any one of [1] to [4] or the partial optical rotation film according to [5],
an interlayer film disposed on one or both sides of the partial optical rotator or the partial optical rotation film.
[7] The partial optical rotator according to any one of [1] to [4], the partial optical rotation film according to [5], or the interlayer film laminate according to [6],
A functional glass comprising two glass plates provided on both sides of the partial optical rotator, the partial optical rotator, or the intermediate film laminate.
[8] The partial optical rotator according to any one of [1] to [4], the partial optical rotation film according to [5], the interlayer film laminate according to [6], or the functional glass according to [7] Head-up display with.
[9] By changing a part of the liquid crystal layer that exhibits optical rotation into an oriented state or an isotropic state that does not exhibit optical rotation in the normal direction, the first region that exhibits optical rotation and the method The method for producing a partial optical rotator according to any one of [1] to [4], wherein the second region that does not exhibit optical rotation in the linear direction is formed in the same liquid crystal layer.

The present invention provides a partial optical rotator that prevents the occurrence of double reflection in an image display area, and that makes it possible to realize a windshield with good appearance in which the border line between the image display area and other areas is difficult to see; A partially optically rotating film, an interlayer laminate, a functional glass, and a head-up display using this can be provided. Furthermore, since the partial optical rotator according to the present invention does not exhibit optical rotation except in the area where optical rotation is expressed (image display area), the glare of light incident on the partial optical rotator from the outside can be reduced by using polarized sunglasses. The effect can be maintained.

FIG. 2 is a schematic diagram showing a partial optical rotator according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a partially optically rotating film according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing an interlayer film laminate according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing functional glass according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a HUD according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below merely illustrate some typical embodiments of the present invention, and various changes can be made within the scope of the present invention. Furthermore, the (meth)acryloyl group described below represents an acryloyl group or a methacryloyl group, and means that they exist independently of each other in the molecule, and (meth)acrylate means acrylate or methacrylate.

[Partial optical rotator]
As shown in FIG. 1, a partial optical rotator 7 according to an embodiment of the present invention has a first region 8 that exhibits optical rotation, and a second region 9 that does not exhibit optical rotation in the normal direction. The liquid crystal layer includes at least one liquid crystal layer. The partial optical rotator 7 may be the liquid crystal layer itself, which includes a first region 8 that exhibits optical rotation and a second region 9 that does not exhibit optical rotation. Here, the term "partial optical rotator" means an optical rotator that has a region that partially exhibits optical rotation. Moreover, "normal direction" means a direction perpendicular to the surface of the partial optical rotator.

The first region 8 that exhibits optical rotation and the second region 9 that does not exhibit optical rotation in the normal direction exist in the same liquid crystal layer. Therefore, the first region 8 and the second region 9 constitute one continuous element. Therefore, the boundary line 10 between the first region 8 and the second region 9 is difficult to distinguish by normal observation with the naked eye, and the appearance characteristics are improved.

The liquid crystal layer is preferably a liquid crystal alignment layer formed from a composition for forming a liquid crystal layer containing a polymerizable liquid crystal monomer or a liquid crystal polymer. The composition for forming a liquid crystal layer contains a polymerizable liquid crystal monomer or a liquid crystal polymer, and may optionally further contain a photopolymerization initiator, an auxiliary agent, and the like. Moreover, the composition for forming a liquid crystal layer may further contain a chiral agent that imparts twist to liquid crystal molecules. On the other hand, even if polymer films such as polycarbonate, which is commonly used for half-wave plates, and cycloolefin polymer, which is used for uniaxially stretched films, are used as materials for the liquid crystal layer, the same liquid crystal These materials cannot be used as materials constituting the partial optical rotator 7 because it is not possible to create a region that exhibits optical rotation and a region that does not exhibit optical rotation in the layer.

Since the partial optical rotator 7 is provided with a liquid crystal layer, the liquid crystal molecules present in the first region 8 are aligned so that the first region 8 corresponding to the image display region acts as a 1/2 wavelength plate. , the liquid crystal molecules present in the second region 9 corresponding to the region other than the image display region are brought into an oriented or isotropic state to the extent that optical rotation is not substantially expressed, and the liquid crystal molecules in each region are hardened by polymerization or the like.・Can be fixed. Further, when chirality is imparted to the polymerizable liquid crystal monomer molecules or a chiral agent is added to the composition for forming a liquid crystal layer, a region containing twisted nematic liquid crystal can be obtained. For this reason, the liquid crystal molecules present in the first region are twisted and oriented, and the liquid crystal molecules present in the second region are fixed in an oriented or isotropic state that does not exhibit optical rotation. , a first region 8 that exhibits optical rotation and a second region 9 that does not exhibit optical rotation can be divided.

When liquid crystal molecules are oriented in the first region 8 that exhibits optical rotation, the first region 8 is preferably a half-wave plate or a twisted nematic liquid crystal layer. In this case, the first region 8 that exhibits optical rotation has the property of giving a phase difference of preferably 0.8π to 1.2π, more preferably π (=λ/2) to the polarization plane of the incident light. It has the function of converting S-polarized light to P-polarized light or converting P-polarized light to S-polarized light. When the first region 8 functions as a half-wave plate, the phase difference is preferably 0.8/2 or more and 1.2/2 or less, more preferably 0.9/2 or more and 1.1/2 or less. It is as follows. When the first region 8 is a twisted nematic liquid crystal layer, the optical rotation angle is preferably 160° or more and 200° or less, more preferably 170° or more and 190° or less, and even more preferably 175° or more and 185° or less.

The second region 9, which does not exhibit optical rotation in the normal direction, is in an oriented or isotropic state in which the liquid crystal molecules do not exhibit optical rotation in the normal direction, and is transparent. Here, "exhibits optical rotation" means that the retardation value exceeds 50 nm at least with respect to the wavelength of the target light, and "does not exhibit optical rotation" means that the retardation value exceeds 50 nm. is 0 nm or more and 50 nm or less, preferably 0 nm or more and 30 nm or less, more preferably 0 nm or more and 20 nm or less, and still more preferably optically isotropic, which means that the retardation value is 0 nm. It is preferable that the second region 9 has no optical rotation not only in the normal direction but in all directions.

The boundary line 10 between the first region 8 that exhibits optical rotation and the second region 9 that does not exhibit optical rotation in the normal direction is difficult to distinguish by normal observation with the naked eye, and as a result, It does not spoil the appearance of the windshield. The visibility of the boundary line 10 can be reduced in this way, unlike the conventional technique in which an optical rotator is separately arranged only in the image display area. This is achieved by forming each region within a layer only with differences in the orientation of liquid crystal molecules.

The partial optical rotator 7 may be a laminate of two or more liquid crystal layers. For example, when the partial optical rotator 7 is a stack of two liquid crystal layers, one of the two liquid crystal layers has a polarization plane of 3π/2 (=3λ/4) of the incident light as a region that exhibits optical rotation. A liquid crystal layer (hereinafter also referred to as "first liquid crystal layer") has a region that provides a phase difference of It is preferable that it is a liquid crystal layer (hereinafter also referred to as "second liquid crystal layer") having a region that gives a phase difference of π/2 (=λ/4) to the plane of polarization and a region that functions as a quarter wavelength plate. . Alternatively, the first liquid crystal layer that provides a phase difference of π with respect to the polarization axis of the incident light is arranged so that the slow axis is 22.5°, and the other liquid crystal layer has a phase difference of π with respect to the polarization plane of the incident light. The second liquid crystal layer may have a laminated structure such that the slow axis of the second liquid crystal layer is 67.5°. It is preferable that the region in the first liquid crystal layer that exhibits optical rotation and the region in the second liquid crystal layer that exhibits optical rotation have similar wavelength dependencies. Here, "similar wavelength dependence" means that the ratio of the retardation value at a wavelength of 400 nm to the retardation value at a wavelength of 550 nm is approximately 1, and the ratio of the retardation values is 0.9 or more and 1. It is preferably .1 or less, more preferably 0.95 or more and 1.05 or less, and even more preferably 0.97 or more and 1.03 or less. The angles formed by the slow axes of the region functioning as a 3/4 wavelength plate in the first liquid crystal layer and the region functioning as a 1/4 wavelength plate in the second liquid crystal layer are relative to the direction of the incident angle of light. It is preferable that the first liquid crystal layer and the second liquid crystal layer are arranged so as to be perpendicular to each other. The angle can be adjusted according to the incident angle of light, as will be described later. By using such a laminate of the first liquid crystal layer and the second liquid crystal layer as the partial optical rotator 7, the quality of the projected image can be improved and the occurrence of double images can be further suppressed.

A partial optical rotator is a liquid crystal layer that exhibits optical rotation by changing a part of the liquid crystal layer that exhibits optical rotation into an oriented state or an isotropic state that does not exhibit optical rotation with respect to the normal direction. It can be manufactured by forming the first region and the second region, which does not exhibit optical rotation in the normal direction, in the same liquid crystal layer.

The specific steps of the method for producing a partial optical rotator include, for example, (1) obtaining a liquid crystal layer on a supporting substrate in which liquid crystal molecules are oriented so as to have a desired optical rotation; (2) step (1). heating a partial region of the liquid crystal layer on the obtained support substrate to form a heated region corresponding to a second region that does not exhibit optical rotation; and (3) heating the heated region. In this state, a step of fixing the orientation of liquid crystal molecules present in the liquid crystal layer is performed.

(1) In the step of obtaining a liquid crystal layer in which liquid crystal molecules are oriented to have a desired optical rotation on a support substrate, a composition for forming a liquid crystal layer is coated on the support substrate so that the thickness is as uniform as possible, and By heating to remove the solvent in the composition for forming a liquid crystal layer, liquid crystal molecules contained in the coating film formed on the support substrate are aligned. The heating temperature and time can be adjusted as appropriate depending on the type of liquid crystal. The amount of the composition for forming a liquid crystal layer applied onto the support substrate can be adjusted as appropriate so that the first region of the partial optical rotator has a desired optical rotation after the coating film is cured.

(2) In the step of heating a part of the liquid crystal layer on the support substrate obtained in (1) to form a heated region corresponding to a second region that does not exhibit optical rotation, the optical rotation is A region where the second region that does not develop is desired to be formed is heated with a hot plate or the like. Heating is preferably carried out to a temperature at which the liquid crystal undergoes an isotropic phase transition, but since the phase transition temperature varies depending on the type of liquid crystal, the heating temperature is adjusted depending on the type of liquid crystal. The heating time can be adjusted as appropriate depending on the fluidity of the liquid crystal. At this time, in order to prevent the liquid crystal orientation of the first region functioning as an optical rotator from changing, it is preferable to maintain the temperature of regions other than the heated region so as not to rise.

(3) In the step of fixing the orientation of liquid crystal molecules present in the liquid crystal layer while the region to be heated is heated, the support is The entire liquid crystal layer on the substrate is irradiated with ultraviolet light using a high-pressure mercury lamp or the like to fix the orientation of the liquid crystal molecules contained within the liquid crystal layer. This makes it possible to obtain a liquid crystal layer in which a region having optical rotation is partially formed. By peeling off the transparent plastic film used as a supporting substrate from the liquid crystal layer thus obtained, a partial optical rotator, which is a cured film of polymerizable liquid crystal, is obtained.

When the partial optical rotator comprises a stack of two or more liquid crystal layers, the position at which each liquid crystal layer is superimposed is determined in advance, and each liquid crystal layer is manufactured according to the steps (1) to (3) above, and then A partial optical rotator can be manufactured by overlapping each liquid crystal layer. It is preferable that the liquid crystal layers are superimposed so that the positions of the regions exhibiting optical rotation of each liquid crystal layer overlap, and the positions of the regions exhibiting optical rotation are coincident.

[Partial optical rotation film]
The partial optical rotation film includes a plastic film as a supporting substrate and a partial optical polarizer formed on the plastic film, and the supporting substrate is not peeled off from the liquid crystal layer prepared as described above, and the state is maintained as it is. It can be made with FIG. 2 shows a partial optical rotation film 17 according to one embodiment of the invention. The partial optical rotator 7 is provided on a plastic film 16. The plastic film 16 serving as the supporting substrate is, for example, a plastic film such as triacetyl cellulose (TAC) or polyethylene terephthalate (PET) film, and is preferably a plastic film that has been subjected to orientation treatment such as rubbing or stretching in advance. The partial optical rotation film 17 may include a plastic film that is uniaxially stretched in the same direction as the orientation direction of the first region that exhibits optical rotation, and the retardation value of the plastic film 16 that is the supporting substrate is as small as possible. preferable. In addition, when the partially optically rotating film 17 is used for a HUD, in order to maintain the visibility of the displayed image, the plastic film 16 serving as the support substrate is preferably transparent in the visible light region, and specifically, it is preferable that the plastic film 16 is transparent in the visible light region. The following visible light transmittance is preferably 50% or more, more preferably 70% or more, and even more preferably 85% or more.

(Composition for forming liquid crystal layer)
The composition for forming a liquid crystal layer contains a polymerizable liquid crystal monomer or a liquid crystal polymer, a photopolymerization initiator, a solvent, and optionally various auxiliary agents. Such a composition for forming a liquid crystal layer is prepared by dissolving a liquid crystal component such as a polymerizable liquid crystal monomer or a liquid crystal polymer in a solvent, and adding a photopolymerization initiator and optionally an auxiliary agent to the resulting solution. can do. The composition for forming a liquid crystal layer may further contain a chiral agent. Further, by imparting chirality to the polymerizable liquid crystal monomer molecules or adding a chiral agent, the liquid crystal contained in the coating film can be converted to twisted nematic liquid crystal. The composition for forming a liquid crystal layer may further include a polymerizable compound having no liquid crystallinity that can react with the polymerizable nematic liquid crystal monomer. The solvent contained in the composition for forming a liquid crystal layer is not particularly limited as long as it can dissolve the liquid crystal monomer, chiral agent, etc. used, but cyclopentanone is preferable.

A polymerizable liquid crystal monomer is a compound that has a polymerizable group in its molecule and exhibits liquid crystallinity within a predetermined temperature range or concentration range. Examples of the polymerizable group include (meth)acryloyl group, vinyl group, chalcone group, cinnamoyl group, and epoxy group. In addition, in order to exhibit liquid crystallinity, it is preferable that there is a mesogenic group in the molecule, and the mesogenic group is, for example, a biphenyl group, a terphenyl group, a (poly)benzoic acid phenyl ester group, a (poly)ether group, or a benzylideneaniline group. , or a rod-like or plate-like substituent such as an acenaphthoquinoxaline group, or a disc-like substituent such as a triphenylene group, a phthalocyanine group, or an azacrown group, that is, a group having the ability to induce liquid crystal phase behavior. Liquid crystal compounds with rod-like or plate-like groups are known in the art as calamitic liquid crystals. Examples of such polymerizable liquid crystal monomers include, specifically, the polymerizable liquid crystals described in JP-A No. 2003-315556, JP-A No. 2004-29824, and Patent No. 5463666, Paliocolor series (manufactured by BASF), Examples include polymerizable nematic liquid crystal monomers such as RMM series (manufactured by Merck). Further, the liquid crystal polymer is preferably a polyester-based or polyether-based liquid crystal polymer. The polymerizable liquid crystal monomer and the liquid crystal polymer can be used alone or in combination.

The chiral agent is preferably a compound that can twist orient the polymerizable liquid crystal monomer in a right-handed or left-handed manner and has a polymerizable group like the polymerizable liquid crystal monomer. Examples of such chiral agents include Paliocolor LC756 (manufactured by BASF) and the compound described in JP-A No. 2002-179668. The amount of the chiral agent added to the composition for forming a liquid crystal layer is, for example, preferably from 0.1 to 15 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal monomer and the liquid crystal polymer. Depending on the HTP value, it can be adjusted as appropriate to obtain a desired pitch.

Furthermore, it is also possible to add a polymerizable compound that is capable of reacting with the polymerizable liquid crystal monomer and the liquid crystal polymer and does not have liquid crystallinity. Examples of such compounds include ultraviolet curable resins and the like. Examples of UV-curable resins include dipentaerythritol hexa(meth)acrylate, reaction products of dipentaerythritol penta(meth)acrylate and 1,6-hexamethylene di-isocyanate, and triisocyanate having an isocyanuric ring and pentaerythritol. Reaction product of erythritol tri(meth)acrylate, reaction product of pentaerythritol tri(meth)acrylate and isophorone-di-isocyanate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate Erythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tris(acryloxyethyl)isocyanurate, tris(methacryloxyethyl)isocyanurate Nurate, reaction product of glycerol triglycidyl ether and (meth)acrylic acid, caprolactone-modified tris(acryloxyethyl)isocyanurate, reaction product of trimethylolpropane triglycidyl ether and (meth)acrylic acid, triglycerol- Di-(meth)acrylate, reaction product of propylene glycol-di-glycidyl ether and (meth)acrylic acid, polypropylene glycol-di-(meth)acrylate, tripropylene glycol-di-(meth)acrylate, polyethylene glycol- Di-(meth)acrylate, tetraethylene glycol-di-(meth)acrylate, triethylene glycol-di-(meth)acrylate, pentaerythritol-di-(meth)acrylate, 1,6-hexanediol-di-glycidyl ether and (meth)acrylic acid, 1,6-hexanediol-di-(meth)acrylate, glycerol-di-(meth)acrylate, ethylene glycol-di-glycidyl ether and (meth)acrylic acid Reaction product, reaction product of diethylene glycol di-glycidyl ether and (meth)acrylic acid, bis(acryloxyethyl)hydroxyethyl isocyanurate, bis(methacryloxyethyl)hydroxyethyl isocyanurate, bisphenol A-di- Reaction product of glycidyl ether and (meth)acrylic acid, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, Polypropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, phenoxyhydroxypropyl (meth)acrylate, acryloylmorpholine, methoxypolyethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate , methoxyethylene glycol (meth)acrylate, methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, glycerol (meth)acrylate, ethyl carbitol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, N,N-dimethyl Examples include aminoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, reaction product of butyl glycidyl ether and (meth)acrylic acid, butoxytriethylene glycol (meth)acrylate, and butanediol mono(meth)acrylate. These can be used alone or in combination. These ultraviolet curable resins without liquid crystallinity must be added to the extent that the liquid crystal layer forming composition does not lose its liquid crystallinity, and is preferably added in an amount of 0.1 parts by mass per 100 parts by mass of polymerizable liquid crystal monomer. The amount added is 1.0 parts or more and 10 parts by mass or less, more preferably 1.0 parts or more and 10 parts by mass or less.

When the polymerizable liquid crystal monomer and other polymerizable compounds are ultraviolet curable, a photopolymerization initiator is added in order to cure the composition containing them with ultraviolet rays. Examples of photopolymerization initiators include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1 (Irgacure 907, manufactured by BASF), 1-hydroxycyclohexyl phenyl ketone (Irgacure, manufactured by BASF) 184), 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone (Irgacure 2959 manufactured by BASF), 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropane- 1-one (Merck Darocur 953), 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one (Merck Darocur 1116), 2-hydroxy-2-methyl-1- Acetophenone compounds such as phenylpropan-1-one (Irgacure 1173 manufactured by BASF), diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651 manufactured by BASF); benzoin, benzoin methyl ether, benzoin Benzoin compounds such as ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl Benzophenone compounds such as -4-methoxybenzophenone (Kayacure MBP manufactured by Nippon Kayaku Co., Ltd.); as well as thioxanthone, 2-chlorothioxanthone (Kayacure CTX manufactured by Nippon Kayaku Co., Ltd.), 2-methylthioxanthone, 2,4-dimethylthioxanthone ( Kayacure RTX), isopropylthioxanthone, 2,4-dichlorothioxanthone (Nippon Kayaku Co., Ltd. Kayacure CTX), 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd. Kayacure DETX), 2,4-diisopropylthioxanthone (Nippon Kayaku Co., Ltd.) Examples include thioxanthone compounds such as Kayacure DITX). Preferably, for example, Irgacure TPO, Irgacure TPO-L, Irgacure OXE01, Irgacure OXE02, Irgacure 1300, Irgacure 184, Irgacure 369, Irgacure 379, Irgacure ure 819, Irgacure 127, Irgacure 907 and Irgacure 1173 (all manufactured by BASF), Particularly preferred are Irgacure TPO, Irgacure TPO-L, Irgacure OXE01, Irgacure OXE02, Irgacure 1300, Irgacure 369 and Irgacure 907. These photopolymerization initiators can be used alone or in a mixture of two or more in any ratio.

When using a benzophenone compound or a thioxanthone compound as a photopolymerization initiator, it is also possible to use an auxiliary agent in order to accelerate the photopolymerization reaction. Such auxiliaries include, for example, triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine, N-methyldiethanolamine, diethylaminoethyl methacrylate, Michler's ketone, 4,4'-diethylaminopropiophenone, 4-dimethyl Examples include amine compounds such as ethyl aminobenzoate, (n-butoxy)ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate.

The amount of the photopolymerization initiator and auxiliary agent added is preferably within a range that does not affect the liquid crystallinity of the composition for forming a liquid crystal layer, and is preferably used in an amount that does not affect the liquid crystallinity of the composition for forming a liquid crystal layer. , preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 8 parts by mass or less. Further, the amount of the auxiliary agent added is preferably 0.5 times or more and 2 times or less based on the mass of the photopolymerization initiator.

(block layer)
It is also possible to provide a blocking layer on the partial optical rotator 7 if necessary. The block layer is a layer provided on one or both sides of the partial optical rotator 7, and is a cured film obtained by drying or curing a coating film formed from a resin composition. When a blocking layer is provided on a partially optically rotating film including a plastic film, it is preferable to provide the blocking layer on a surface opposite to the surface of the partially optically rotating film including the plastic film. The partial optical rotator 7 changes the phase difference value of the first region 8 that exhibits optical rotation by being placed in a high-temperature environment, such as an environment in which an automobile windshield is used, while in contact with an in-vehicle interlayer film. may decrease. This is thought to be due to the influence of the plasticizer, etc. contained in the vehicle-mounted interlayer film. The blocking layer is preferably placed between the partial optical rotator 7 and the vehicle-mounted intermediate film. By using the block layer, it is possible to prevent the partial optical rotator 7 from coming into direct contact with a layer that may cause deterioration of an in-vehicle interlayer film, etc., and as a result, a decrease in the phase difference value of the partial optical rotator 7 can be suppressed. I can do it.

The resin composition for forming the block layer contains, for example, one or more resins selected from the group consisting of polyvinyl alcohol resin, polyester resin, polyurethane resin, polyamide resin, polyimide resin, and acrylic resin, and A block layer can be formed by applying and drying a resin composition. Further, when the resin composition for forming the block layer is, for example, an ultraviolet curable resin composition, a thermosetting resin composition, or a mixture thereof, the block layer can be formed by applying and curing the resin composition. Obtainable. From the viewpoints of transparency, applicability, production cost, etc., the resin composition for forming the block layer is preferably an ultraviolet curable resin composition.

The ultraviolet curable resin composition contains at least an ultraviolet curable resin and a photopolymerization initiator, and optionally contains further components. As the ultraviolet curable resin, resins having at least two (meth)acryloyl groups in the molecule are preferable, such as polyfunctional (meth)acrylates, polyfunctional urethane (meth)acrylates, and polyfunctional epoxy (meth)acrylates. , polyfunctional polyester acrylate, etc. These may be used alone or in combination of two or more. By using these ultraviolet curable resins, it is possible to prevent the phase difference value of the partial optical rotator 7 from decreasing due to the intrusion of plasticizers.

Among ultraviolet curable resins, it is preferable that the resin composition contains a resin having at least three (meth)acryloyl groups in the molecule in a proportion of 10% by mass or more and 90% by mass or less, and 30% by mass or more and 70% by mass or less. % mass or less is more preferable. By using such a resin, it is possible to further enhance the effect of preventing a decrease in the retardation value of the partial optical rotator 7 due to the intrusion of a plasticizer.

Examples of polyfunctional (meth)acrylates having three or more (meth)acryloyl groups include: Examples of polyfunctional (meth)acrylates having three or more (meth)acryloyl groups include pentaerythritol tetra(meth)acrylate. , pentaerythritols such as pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate; Examples include methylols such as trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate; Isocyanurates such as trisacryloxyethyl isocyanurate and trisallyl isocyanurate. .

Examples of polyfunctional (meth)acrylates having two (meth)acryloyl groups include dipentaerythritol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polyethylene glycol di(meth)acrylate, and tripropylene glycol. Di(meth)acrylate, di(meth)acrylate of ε-caprolactone adduct of neopentyl glycol hydroxypivalate (for example, KAYARADHX-220, HX-620, manufactured by Nippon Kayaku Co., Ltd.), EO adduct of bisphenol A Examples include di(meth)acrylate.

Examples of the polyfunctional polyester acrylate include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, trimethylolpropane tri(meth)acrylate, and trimethylolpropane polyethoxy. Tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol octa(meth)acrylate, etc. can be mentioned.

Examples of polyfunctional urethane (meth)acrylates include polyols such as ethylene glycol, 1,4-butanediol, polytetramethylene glycol, neopentyl glycol, polycaprolactone polyol, polyester polyol, polycarbonate diol, and polytetramethylene glycol. , hexamethylene diisocyanate, alicyclic polyisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and other organic polyisocyanates; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate; Reactants of acrylate, 1,4-butanediol mono(meth)acrylate, ε-caprolactone adduct of 2-hydroxyethyl(meth)acrylate, and ethylenically unsaturated compounds containing hydroxyl groups such as pentaerythritol tri(meth)acrylate. etc. can be mentioned.

Examples of polyfunctional epoxy (meth)acrylates include polyglycidyl compounds (bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, trisphenolmethane epoxy resin, polyethylene glycol diglycidyl ether, glycerin polyglycidyl Examples include epoxy (meth)acrylates which are reaction products of (meth)acrylic acid and (meth)acrylic acid.

Examples of photopolymerization initiators include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone; 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, etc. acetophenones; anthraquinones such as 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; thioxanthones such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, phosphine oxides such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like. These may be used alone or in combination of two or more.

The photopolymerization initiator is preferably contained in the solid content of the block layer forming resin composition from 0.01% by mass to 10% by mass, more preferably from 1% by mass to 7% by mass.

The resin composition for forming the block layer further contains a solvent. Such a solvent is not particularly limited as long as it can dissolve the resin and photopolymerization activator used, and examples thereof include methyl ethyl ketone, methyl isobutyl ketone, isopropanol, cyclopentanone, water, etc., and preferably methyl ethyl ketone. , cyclopentanone, and water. Further, these solvents can be added in any proportion, and only one type of solvent may be added, or a plurality of solvents may be used in combination. These solvents are removed by drying in the drying process.

The block layer forming resin composition may further contain a curing accelerator. Examples of the curing accelerator include triethanolamine, diethanolamine, N-methyldiethanolamine, 2-methylaminoethylbenzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid isoamino ester, amines such as EPA, and 2-mercaptobenzothiazole. Hydrogen donors such as The amount of these curing accelerators used is preferably 0% by mass or more and 5% by mass or less in the solid content of the resin composition for forming a block layer.

Furthermore, leveling agents, antifoaming agents, ultraviolet absorbers, light stabilizers, antioxidants, polymerization inhibitors, crosslinking agents, etc. are added to the block layer forming resin composition as necessary to achieve the desired purpose. It is also possible to add functionality. Examples of the leveling agent include fluorine compounds, silicone compounds, and acrylic compounds. Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, and triazine compounds. Examples of the light stabilizer include hindered amine compounds and benzoate compounds. Examples of antioxidants include phenolic compounds. Examples of the polymerization inhibitor include methoquinone, methylhydroquinone, and hydroquinone. Examples of the crosslinking agent include the aforementioned polyisocyanates and melamine compounds. The amount of each of these components added can be determined as appropriate depending on the function to be provided.

The thickness of the block layer is preferably 0.1 μm or more and 50 μm or less, more preferably 1 μm or more and 20 μm or less. The block layer is formed by applying a resin composition for forming a block layer onto the surface of the partial optical rotator so that the film thickness after drying is in the above-mentioned preferred range, and after drying, curing by ultraviolet irradiation or heating to form a cured film. It can be obtained by forming. As a method for applying the resin composition for forming a block layer, for example, a known method such as bar coater coating can be used.

When the block layer forming resin composition is an ultraviolet curable type, ultraviolet rays are irradiated for curing, but electron beams or the like may also be used. When curing with ultraviolet rays, an ultraviolet irradiation device having a xenon lamp, a high-pressure mercury lamp, a metal halide lamp, an LED, etc. can be used as a light source, and the amount of light, arrangement of the light source, etc. are adjusted as necessary. When using a high-pressure mercury lamp, it is preferable to cure at a transport speed of 5 to 60 m/min for one lamp having an energy of 80 to 120 W/cm ² . On the other hand, when curing with an electron beam, it is preferable to use an electron beam accelerator having an energy of 100 to 500 eV, and in this case, it is not necessary to use a photopolymerization initiator.

[Intermediate film laminate]
The interlayer film laminate includes a partial optical rotation element or a partial optical rotation film, and an intermediate film disposed on one or both sides of the partial optical rotation element or partial optical rotation film. The interlayer film laminate can be obtained by laminating a partial optical rotator or a partial optical rotation film on one side with one interlayer film or on both sides with two interlayer films. FIG. 3 shows an interlayer film laminate 12 according to an embodiment of the present invention. In the interlayer film stack 12, the partial optical rotator 7 is laminated with two interlayer films 11. As the intermediate film 11, a commonly used vehicle-mounted intermediate film can be used. The intermediate film 11 is made of, for example, polyvinyl butyral resin (PVB), polyvinyl alcohol resin (PVA), or ethylene-vinyl acetate copolymer resin (EVA). Such an interlayer film is commonly used as an interlayer film for laminated glass.

The interlayer film may contain UV absorbers, antioxidants, antistatic agents, heat stabilizers, colorants, adhesion regulators, etc., as appropriate. The membrane is important in making high-performance thermally insulating laminated glass. Fine particles that absorb infrared rays include metals, oxides, and nitrides of Sn, Ti, Zn, Fe, Al, Co, Ce, Cs, In, Ni, Ag, Cu, Pt, Mn, Ta, W, V, and Mo. Ultrafine particles of conductive material such as Sb or F doped alone, or a composite containing at least two of these are used. When using heat-insulating laminated glass for architectural windows that require transparency and automobile windows such as windshields, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and fluorine are used, which are transparent in the visible light range. Particular preference is given to using doped tin oxide. The particle size of the fine particles that absorb infrared rays and are dispersed in the interlayer film is preferably 0.2 μm or less. If the particle size of the fine particles is 0.2 μm or less, it can absorb infrared rays while suppressing light scattering in the visible light range, does not generate haze, maintains radio wave transmittance and transparency, and has adhesive properties. It maintains physical properties such as transparency and durability equivalent to those of an unadded interlayer film, and furthermore, it can be laminated and vitrified using a normal laminated glass production line. Further, the intermediate film may be partially colored, or may have a structure in which a layer having a sound insulation function is sandwiched between two intermediate films.

There is no particular restriction on the method of laminating the interlayer film and the partial optical rotation element or the partial optical rotation film, but examples include a method of simultaneously laminating the intermediate film, the partial optical rotation element, or the partial optical rotation film by pressure bonding using nip rolls. . If the nip rolls can be heated during lamination, it is also possible to press while heating. The heating temperature and compression pressure can be within normal ranges. Furthermore, if the adhesion between the interlayer film and the partial optical rotator or the partial optical rotation film is poor, the interlayer film may be surface-treated by corona treatment, plasma treatment, etc. before lamination.

[Functional glass]
The functional glass includes a partial optical rotator, a partial optical rotation film, or an interlayer laminate, and two glass plates provided on both sides of the partial optical rotator, partial optical rotation film, or interlayer laminate. As shown in FIG. 4, in the functional glass 14 according to one embodiment of the present invention, an interlayer film laminate 12 is sandwiched between two glass plates 13. The functional glass 14 can be obtained by pressing two glass plates on both sides of the interlayer film laminate 12 at high temperature and high pressure. The glass plate is not particularly limited as long as it has transparency that allows the scenery through the glass to be sufficiently visible even when functional glass is used as architectural windows or laminated glass for automobiles. Further, the thickness, shape, etc. of the glass plate are not particularly limited as long as they do not affect the reflection of display light, and can be appropriately designed depending on the purpose. When using functional glass as an automobile windshield, it is preferable to adjust the reflectance so that the visible light transmittance of the functional glass is 70% or more. In place of the glass plate, a transparent plastic plate without optical anisotropy can also be used.

As a specific example of a method for producing functional glass, first, two glass plates are prepared. When used as laminated glass for automobile windshields, it is preferable to use soda lime glass made by the float method. The glass may be transparent or colored green, and is not particularly limited. The thickness of these glass plates is usually about 2 mm, but in response to recent demands for lighter glass, glass plates with a slightly thinner thickness can also be used. Cut the glass plate into a predetermined shape, chamfer the glass edges, and clean. When a black frame-like or dot-like print is required, it is printed on a glass plate. When a curved surface shape is required, such as a windshield, the glass plates are heated to 650°C or higher, and then shaped by pressing with a mold or bending by their own weight so that the two sheets have the same surface shape. Cool the glass. At this time, if the cooling rate is made too fast, stress distribution will occur in the glass plate, resulting in a strengthened glass, so slow cooling is performed. One of the glass plates thus produced is placed horizontally, the interlayer film laminate is placed on top of it, and the other glass plate is placed on top of it. Alternatively, a method may be used in which an interlayer film, a partial optical rotator or a partial optical rotation film, and an interlayer film are stacked in order on a glass plate, and finally the other glass plate is placed. Next, the partial optical rotator, partial optical rotation film, or interlayer film protruding from the edge of the glass is cut and removed using a cutter. Thereafter, preliminary adhesion is performed by heating to a temperature of 80° C. to 100° C. while degassing the air present between the glass plates, interlayer film, partial optical rotator, or partial optical rotatory film laminated in a sandwich-like manner. There are two ways to degas the air: the bag method, in which a laminate of glass plate/interlayer film/partial optical rotator or partial optical rotator film/interlayer film/glass plate is wrapped in a rubber bag made of heat-resistant rubber, and There are two types of ring methods in which only the portion is covered with a rubber ring for sealing, and either method may be used. After the preliminary adhesion is completed, place the laminate of glass plate/interlayer film/partial optical rotator or partial optical rotation film/interlayer film/glass plate taken out from the rubber bag, or the laminate with the rubber ring removed, into an autoclave, and place the laminate in an autoclave to weigh 10 to 15 kg. The sample is heated to 120° C. to 150° C. under a high pressure of /cm ² , and heated and pressurized under these conditions for 20 minutes to 40 minutes. After the treatment, the pressure is removed after cooling to 50° C. or lower, and the functional glass having the configuration of glass plate/interlayer film/partial optical rotator or partial optical rotation film/interlayer film/glass plate is taken out from the autoclave.

Functional glass can be used as windshields, side glasses, rear glasses, and roof glasses of regular cars, small cars, light cars, large special cars, and small special cars. Additionally, functional glass can be used as windows for railroad vehicles, ships, and aircraft, as well as architectural and industrial window materials. Functional glass can also be used in a form in which a member having a UV cut function and a light control function is laminated or bonded on the surface.

[Heads up display]
The head-up display includes a partial optical rotator, a partial optical rotation film, an interlayer film laminate, or a functional glass. Preferably, the head-up display further includes, as a light source, an image display means that emits display light indicating a display image. It is preferable that the head-up display is configured such that the display light from the image display means is incident on the functional glass at an appropriate angle in an S-polarized state.

FIG. 5 shows a schematic diagram of a head-up display 20 according to an embodiment of the present invention. The head-up display 20 includes an image display means 2 that emits display light indicating a display image, a reflector 3 that reflects the display light emitted from the image display means 2, and a reflector 3 that reflects the display light emitted from the image display means. It includes a polarizing plate 15 that converts into polarized light, and a functional glass 4 into which the display light emitted from the image display means 2 enters. Display light emitted from the image display means 2 is reflected by a reflecting mirror 3, and the reflected display light passes through a polarizing plate 15 to become S-polarized light, and is made to enter functional glass 4. As a result, the S-polarized light reaches the observer 1 via the optical path 5, and the virtual image 6 of the displayed image can be visually recognized. Note that in the head-up display 20 shown in FIG. 5, the display light emitted from the image display means 2 enters the functional glass 4 via the reflecting mirror 3; If the display light emitted from the image display means 2 is S-polarized light, the display light from the image display means 2 may be inputted into the functional glass 4 from the means 2 without passing through the polarizing plate 15. The light may be directly incident on the transparent glass 4.

(functional glass)
As the functional glass 4, the above-mentioned functional glass can be used. When the first region of the partial optical rotator in the functional glass 4 functions as a half-wave plate, the functional glass 4 changes the optical rotation of the partial optical rotator 7 according to the incident angle of the incident S-polarized light. It is preferable that the first region to be developed be arranged so that the angle θ formed with the slow axis falls within the following range.

When the angle of incidence of the S-polarized light on the functional glass 4 is 45°, the range of the angle θ between the slow axis of the first region of the partial optical rotator and the polarization axis of the incident S-polarized light is preferably 35°. It is at least 44 degrees, more preferably at least 37 degrees, at most 44 degrees, even more preferably at least 40 degrees and at most 44 degrees, particularly preferably at least 41 degrees and at most 43 degrees. When the incident angle of S-polarized light is 50°, the range of θ is preferably 35° or more and 44° or less, more preferably 38° or more and 44° or less, and even more preferably 39° or more and 43° or less. The angle is particularly preferably 40° or more and 42° or less. Further, when the incident angle of S-polarized light is 56° or 60°, the range of θ is preferably 35° or more and 44° or less, more preferably 37° or more and 43° or less, and even more preferably 38°. The angle is not less than 42°, and particularly preferably not less than 39° and not more than 41°. Further, when the incident angle of S-polarized light is 65°, the range of θ is preferably 35° or more and 44° or less, more preferably 36° or more and 42° or less, and even more preferably 37° or more and 41°. The angle is preferably at least 38° and at most 40°. When using glass with a refractive index of 1.48 as the glass plate of the functional glass 4 and making S-polarized light incident on the glass plate at the Brewster angle (approximately 56°), the range of θ is preferably 35° or more and 44° or less. The angle is more preferably 37° or more and 43° or less, further preferably 38° or more and 42° or less, particularly preferably 39° or more and 41° or less.

In order to further improve the quality of projected images and the occurrence of double images, a first liquid crystal layer has a region that functions as a 3/4 wavelength plate, and a second liquid crystal layer has a region that functions as a 1/4 wavelength plate. A partial optical rotator in which a region functioning as a 3/4 wavelength plate of the first liquid crystal layer and a region functioning as a 1/4 wavelength plate of the second liquid crystal layer have similar wavelength dependence. It is preferable to use a partial optical rotator having . At that time, when the region functioning as a 3/4 wavelength plate and the region functioning as a 1/4 wavelength plate having similar wavelength dispersion properties are viewed from the direction of the incident angle of the light source, their respective slow axes are orthogonal. It is particularly preferable to use a partial optical rotator in which a first liquid crystal layer and a second liquid crystal layer are laminated in a crossing manner. By using such a partial optical rotator, when full-color display is performed using a white light source, it is possible to accurately convert the polarization axis from S-polarized light of each wavelength to P-polarized light, or from P-polarized light of each wavelength to S-polarized light. Therefore, the quality of the projected image can be improved and the occurrence of double images can be further suppressed.

The angle θ between the slow axis of the region that functions as a 3/4 wavelength plate, the slow axis of the region that functions as a 1/4 wavelength plate, and the optical axis of the incident S-polarized light is determined from the light source to the glass plate. It is preferable to adjust it as follows depending on the incident angle of .

When the incident angle of S-polarized light is 90° (incidence from the front), it is preferable that the slow axes of the 3/4 wavelength plate region and the 1/4 wavelength plate region are perpendicular to each other. On the other hand, for example, when the incident angle of S-polarized light is 45°, the polarization axis of the incident S-polarized light and the slow axis of one of the 3/4 wavelength plate region or the 1/4 wavelength plate region are The range of the angle θ is preferably 35° or more and 44° or less, more preferably 37° or more and 44° or less, even more preferably 40° or more and 44° or less, and particularly preferably 41° or more and 43° or less. It is. In this case, the slow axis of the 3/4 wavelength plate region or the other region of the 1/4 wavelength plate is the same as that of the 3/4 wavelength plate region or the 1/4 wavelength plate region whose θ range has been adjusted. It intersects with the slow axis preferably at -44° or more and -35° or less (hereinafter referred to as "intersection angle range"), more preferably -44° or more and -37° or less, and The angle is preferably -44° or more and -40° or less, particularly preferably -43° or more and -41° or less. That is, for example, if the range of the angle θ between the slow axis of the 3/4 wavelength plate region and the optical axis of S-polarized light is 40° or more and 44° or less, the slow axis of the 1/4 wavelength plate region means intersecting the slow axis of the region of the 3/4 wavelength plate at an angle of -44° or more and -40° or less. When the incident angle of S-polarized light is 50°, the relationship between the slow axis of the 3/4 wavelength plate region and the slow axis of the 1/4 wavelength plate region is preferably such that the range of θ is 35° or more. 44° or less, and the crossing angle range is -44° or more and -35° or less, more preferably, the range of θ is 38° or more and 44° or less, and the crossing angle range is -44° or more and -38°. More preferably, the range of θ is 39° or more and 43° or less, the intersection angle range is -43° or more and -39° or less, and particularly preferably the range of θ is 40° or more and 42° or less. The intersection angle range is -42° or more and -40° or less. Further, when the incident angle of S-polarized light is 56° or 60°, the relationship between the slow axis of the 3/4 wavelength plate region and the slow axis of the 1/4 wavelength plate region is preferably The range is 35° or more and 44° or less, the intersection angle range is -44° or more and -35° or less, and more preferably the θ range is 37° or more and 43° or less, and the intersection angle range is - 43° or more and -37° or less, more preferably the range of θ is 38° or more and 42° or less, and the range of the intersection angle is -42° or more and -38° or less, particularly preferably the range of θ is 39° or more and 41° or less, and the range of the intersection angle is -41° or more and -39° or less. Furthermore, when the incident angle of S-polarized light is 65°, the relationship between the slow axis of the 3/4 wavelength plate region and the slow axis of the 1/4 wavelength plate region is preferably 35°. The range of the crossing angle is -44° to -35°, more preferably the range of θ is 36° to 42°, and the range of the crossing angle is -42° to -42°. -36° or less, more preferably the range of θ is 37° or more and 41° or less, the range of the intersection angle is -41° or more and -37° or less, particularly preferably the range of θ is 38° The range of the intersection angle is -40° or more and -38° or less.

When S-polarized light is incident on the functional glass at the Brewster angle (approximately 56°), preferably the range of θ is 35° or more and 44° or less, and the intersection angle range is -44° or more and -35° or less. More preferably, the range of θ is 37° or more and 43° or less, the range of the intersection angle is -43° or more and -37° or less, and even more preferably the range of θ is 38° or more and 42° or less. Yes, the crossing angle range is -42° or more and -38° or less, particularly preferably the θ range is 39° or more and 41° or less, and the crossing angle range is -41° or more and -39° or less. .

A partial optical rotator in which the first liquid crystal layer and the second liquid crystal layer are laminated at the angles described above, when viewed from the incident angle of light, is aligned with the slow axis of the region of the 3/4 wavelength plate. The slow axes of the regions of the quarter-wave plate are approximately perpendicular to each other, and the first region substantially becomes a half-wave plate. Here, the "approximately orthogonal state" preferably ranges from orthogonal (90°) to ±5°. Further, the slow axis of the first region of the partial optical rotator can be regarded as the slow axis direction of the region of the 3/4 wavelength plate.

(Image display means)
The image display means 2 is not particularly limited as long as it can emit the desired S-polarized light before it finally reaches the functional glass 4, but for example, it may be a liquid crystal display device such as a liquid crystal projector. (LCD), organic EL display (OLED), etc. When the image display means 2 is a liquid crystal display device, the emitted light is usually linearly polarized light, so it can be used as is. On the other hand, when the image display means 2 is an organic EL display, the emitted light can be made into linearly polarized light by arranging a polarizing plate near the emitting port. In addition, when using a head-up display in a car, a liquid crystal display device or an organic EL display has an optical member such as a polarizing plate or a 1/2 wavelength plate placed at a light exit such as a dashboard to display images. It is also possible to adjust so that the means 2 can emit S-polarized light. Further, the light source used in the image display means 2 is not particularly limited, and a laser light source, an LED light source, etc. can be used.

(Polarizer)
The polarizing plate 15 is not particularly limited as long as it has the function of converting the display light emitted from the image display means 2 into S-polarized light. Further, the polarizing plate 15 may be placed at any position as long as the display light emitted from the image display means 2 reaches the functional glass 4, and the polarizing plate 15 may be placed at any position between the image display means 2 and the reflecting mirror 3. It may be placed in between. If the display light emitted from the image display means 2 is S-polarized light, the polarizing plate 15 may not be used.

In the head-up display 20, the projection light is projected only onto the first region 8 that functions as an optical rotator, and an image without double images is displayed in the first region 8. In addition, no image is projected onto the second region 9 which does not exhibit optical rotation in the normal direction, and since the second region 9 does not have optical rotation, it is This allows you to maintain the light-blocking effect of polarized sunglasses.

Hereinafter, the present invention will be illustrated in detail with reference to Examples. In the examples, parts refer to parts by weight.

[Example 1]
<Preparation of partial optical rotator>
A coating liquid (A), which is a liquid crystal composition having the composition shown in Table 1, was prepared.

Using the prepared coating liquid (A), a partially optically rotating film was produced according to the following procedure. As a supporting substrate, a TAC film (thickness: 80 μm) that had been rubbed by the method described in Example 1 of JP-A No. 2002-90743 was prepared in a 10 cm square so that the rubbing angle was 40 degrees with respect to the sides. I used the one cut out.

(1) The coating liquid (A) was applied at room temperature onto the rubbed surface of the TAC film using a wire bar so that the thickness of the coating film obtained after drying was 2 μm.
(2) The obtained coating film was heated at 50° C. for 2 minutes to remove the solvent and turn it into a liquid crystal phase.
(3) Next, using a hot plate, the outer peripheral portion of the film was heated to 140° C. up to a position approximately 2 cm from the end of each side of the film.
(4) While the outer periphery of the film is still heated to 140°C, UV irradiation is applied from above using a high-pressure mercury lamp (manufactured by Harrison Toshiba Lighting Co., Ltd.) at an output of 120 W for 5 to 10 seconds to fix the liquid crystal phase and make the TAC film. A partial optical rotator having a liquid crystal layer partially functioning as a 1/2 wavelength plate was formed thereon to produce a partial optical rotation film.

<Formation of block layer>
A coating liquid (B), which is a composition for forming a block layer, having the composition shown in Table 2 was prepared.

(1) On the liquid crystal layer prepared above, the coating liquid (B) was applied at room temperature using a wire bar so that the thickness of the block layer obtained after drying was 1.5 μm.
(2) The obtained coating film was heated at 40°C for 1 minute to remove the solvent, and then UV irradiated with a high-pressure mercury lamp (manufactured by Harrison Toshiba Lighting Co., Ltd.) at 120W output for 5 to 10 seconds to remove the resin. A partial optical rotator having a block layer was prepared by curing.

<Preparation of interlayer film laminate>
Two transparent polyvinyl butyral interlayer films each having a thickness of 0.38 mm and containing triethylene glycol di-2-ethylhexanoate as a plasticizer were used. A partial optical rotator having a blocking layer was disposed between two polyvinyl butyral interlayer films, and the interlayer films were then pressure-bonded using a laminator to produce an interlayer film laminate.

<Production of functional glass>
The interlayer film laminate produced above was stacked on a 10 cm square transparent glass plate with a thickness of 2 mm, and then another transparent glass plate of the same size was stacked on top. Next, the excess portion of the interlayer film laminate protruding from the edge of the glass plate was cut and removed using a razor. This was wrapped in a rubber bag, degassed for 10 minutes in an autoclave heated to 90°C, and preliminarily bonded. After cooling this to room temperature, it was taken out from the rubber bag and heated and pressurized again in an autoclave at 135° C. under a high pressure of 12 kg/cm ² for 30 minutes to produce a functional glass with an interlayer film laminate inserted therein.

When the obtained functional glass was observed, it had a good appearance, and the boundary line between the central portion that functions as an optical rotator and the outer peripheral portion that does not function as an optical rotator could not be visually confirmed. On the other hand, when functional glass was placed between the polarizing plates arranged in crossed Nicols, it was confirmed that there was a region approximately in the center where a phase difference of approximately 6 cm square was expressed. Next, using an automatic birefringence meter (Oji Scientific Instruments "KOBRA-21ADH"), we measured the retardation value between the center and outer circumference of the functional glass, and the retardation value at the center was 270 nm. On the other hand, the phase difference value at the outer periphery was 15 nm.

<Fabrication of head-up display and evaluation of displayed images>
A head-up display was fabricated with the arrangement shown in FIG. As the image display means 2, a commercially available liquid crystal projector was used. A polarizing plate 15 (SHC-13U, manufactured by Polatechno Co., Ltd.) was installed so that the display light emitted from the image display means 2 was emitted toward the functional glass 4 as S-polarized light. As the reflecting mirror 3, a commercially available mirror was used. The functional glass 4 was arranged so that the slow axis of the partial optical rotator was 40° with respect to the emitted S-polarized light. Next, the position of the functional glass 4 was adjusted so that the incident angle of the S-polarized light emitted from the image display means 2 via the polarizing plate 15 was the Brewster angle of the glass (approximately 56°).

When an image was projected onto the center of the functional glass 4 (within the area where the liquid crystal is oriented), no double reflection was observed in the displayed image, and the displayed image was extremely bright and clear without any color change. Projected. Furthermore, with respect to the reflected light from the outside that enters through the functional glass 4, the reflected light that passes through the outer peripheral region can be blocked by wearing polarized sunglasses.

[Comparative example 1]
In producing the above partial optical rotator, an optical rotator (1/2 wavelength plate) was produced in the same manner as in Example 1 except that the outer circumferential portion was not heated in step (3). The obtained optical rotator (1/2 wavelength plate) was cut into 6 cm square pieces and placed between two interlayer films in the same manner as in Example 1 to produce an interlayer film laminate. A laminated glass was produced in which the interlayer film laminate was inserted in the center between two glass plates.

When observing the obtained laminated glass, the outer boundary line of the optical rotator (1/2 wavelength plate) cut into a 6 cm square can be easily seen with the naked eye, making it possible to identify the location where the optical rotator is placed. The appearance characteristics were inferior to those of Example 1.

From the above results, by using the functional glass of Example 1, the deterioration of visibility at the boundary line between the central part that exhibits optical rotation and the outer peripheral part that does not exhibit optical rotation can be reduced, and it can be used as a windshield. It turns out that the appearance can be greatly improved.

1 Observer 2 Image display means 3 Reflector 4 Functional glass 5 Optical path 6 Virtual image 7 Partial optical rotator 8 First region 9 Second region 10 Boundary line 11 Intermediate film 12 Intermediate film laminate 13 Glass plate 14 Functional glass 15 Polarizing plate 20 Head-up display
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Claims (9)

At least one liquid crystal layer including a first region that exhibits optical rotation and a second region that does not exhibit optical rotation in the normal direction,
A partial optical rotator, wherein the first region and the second region are present in the same liquid crystal layer. The partial optical rotator according to claim 1, wherein the liquid crystal layer is a liquid crystal alignment layer formed from a composition for forming a liquid crystal layer containing a polymerizable liquid crystal monomer or a liquid crystal polymer. 3. The partial optical rotator according to claim 1, wherein the first region is a half-wave plate or a twisted nematic liquid crystal layer. The partial optical rotator according to any one of claims 1 to 3, wherein the first region provides a phase difference of 0.8π or more and 1.2π or less to the polarization plane of the incident light. plastic film and
The partial optical rotator according to any one of claims 1 to 4 formed on the plastic film;
A partially optically rotating film comprising: The partial optical rotator according to any one of claims 1 to 4 or the partial optical rotation film according to claim 5,
an intermediate film disposed on one or both sides of the partial optical rotator or the partial optical rotation film;
An interlayer film laminate comprising: The partial optical rotator according to any one of claims 1 to 4, the partial optical rotation film according to claim 5, or the interlayer film laminate according to claim 6,
two glass plates provided on both sides of the partial optical rotator, the partial optical rotation film, or the interlayer film laminate;
Functional glass with Comprising the partial optical rotator according to any one of claims 1 to 4, the partial optical rotation film according to claim 5, the interlayer film laminate according to claim 6, or the functional glass according to claim 7. Head-up display. By changing a part of the liquid crystal layer that exhibits optical rotation to an orientation state or an isotropic state that does not exhibit optical rotation in the normal direction, 5. The method for producing a partial optical rotator according to claim 1, wherein the second region that does not exhibit optical rotation is formed in the same liquid crystal layer.

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