JP6492397B2 - Light control element and in-vehicle liquid crystal display device - Google Patents

Description

  The present invention relates to a light control element and an in-vehicle liquid crystal display device including the same.

  In recent years, many vehicles are provided with a car navigation system. Liquid crystal display devices are widely used as display devices for car navigation systems. This liquid crystal display device is generally installed between the driver's seat and the passenger seat on the dashboard of the vehicle.

  The liquid crystal display device is required to be able to see the screen when viewed from any of the driver's seat, the passenger seat, and the rear seat. Therefore, generally, the screen of the liquid crystal display device is required to be bright and clear. However, if the screen of the liquid crystal display device is bright, reflection on a window such as a windshield may occur during night driving. The image of the liquid crystal display device reflected on the windshield may interfere with driving when entering the driver's field of view.

  Therefore, various techniques have been developed in the past to prevent the reflection of the screen of the liquid crystal display device on the windshield. If the example is given, the technique of the following patent documents 1-9 will be mentioned.

JP 2004-245918 A JP 2005-275262 A JP 2006-208606 A JP 2010-060674 A JP-A-1-302383 Japanese Patent No. 2561483 JP-T-2004-514167 Japanese Patent No. 4856805 JP 2004-245918 A

  However, the conventional techniques as described in Patent Documents 1 to 9 have limitations on cost or installation mode. Therefore, it has been required to suppress the reflection of the screen of the in-vehicle liquid crystal display device on the windshield by a technique different from the conventional one.

  The present invention was devised in view of the above-mentioned problems, and can be manufactured relatively easily and can suppress reflection on the windshield without significantly impairing the visibility of the screen of the in-vehicle liquid crystal display device. It is an object of the present invention to provide a light control element; and an in-vehicle liquid crystal display device that can be manufactured relatively easily and can suppress the reflection on the windshield without significantly impairing the visibility of the screen.

As a result of intensive studies to solve the above problems, the present inventor made a comparison by providing a light control element including a cholesteric resin layer having a light transmittance in a predetermined range in the visible light region on the screen of the liquid crystal display element for vehicle use. The present invention has been completed by finding that it can be configured easily and easily, and that reflection on the windshield can be prevented without significantly impairing the visibility when the screen is directly viewed.
That is, the present invention is as follows.

[1] A light control element for being provided on a screen of an in-vehicle liquid crystal display element provided with a light source side polarizing plate and a viewing side polarizing plate,
The said light control element is provided with the cholesteric resin layer whose average value of the light transmittance in visible region is 60%-75%.
[2] A retardation layer is provided on the viewing side polarizing plate side of the cholesteric resin layer,
The light control element according to [1], wherein the retardation layer has an in-plane retardation of ¼ wavelength.
[3] The light control element according to [2], wherein an angle formed between a transmission axis of the viewing side polarizing plate and a slow axis of the retardation layer is approximately 45 °.
[4] The light control element according to any one of [1] to [3], further including an antireflection layer on the opposite side of the cholesteric resin layer from the viewing-side polarizing plate.
[5] In-vehicle liquid crystal comprising a light source, a light source side polarizing plate, a liquid crystal cell, a viewing side polarizing plate, and the light control element according to any one of [1] to [4] in this order. Display device.

The light control element of the present invention can be manufactured relatively easily and can suppress the reflection on the windshield without significantly impairing the visibility of the screen of the in-vehicle liquid crystal display device.
The in-vehicle liquid crystal display device of the present invention can be manufactured relatively easily and can suppress the reflection on the windshield without greatly impairing the visibility of the screen.

FIG. 1 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a schematic view schematically showing a state in which the liquid crystal display device according to the first embodiment of the present invention is provided in a vehicle. FIG. 3 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to the second embodiment of the present invention. FIG. 4 is a schematic view schematically showing a state in which the liquid crystal display device according to the second embodiment of the present invention is provided in a vehicle. FIG. 5 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to the third embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and exemplifications, and can be carried out by being arbitrarily changed without departing from the scope of the claims of the present invention and the equivalents thereof.

  In the following description, “long” means one having a length of at least 5 times the width, preferably 10 times or more, specifically a roll shape. It has a length enough to be wound up and stored or transported. Although the upper limit of the magnification of the length with respect to the width is not particularly limited, it may be usually 5000 times or less.

  The “polarizing plate” and the “¼ wavelength plate” include not only a rigid member but also a flexible member such as a resin film.

  The in-plane retardation of a film is a value represented by (nx−ny) × d unless otherwise specified. Here, nx represents a refractive index in a direction (in-plane direction) perpendicular to the thickness direction of the film and giving a maximum refractive index. Ny represents the refractive index in the in-plane direction of the film and perpendicular to the nx direction. Furthermore, d represents the thickness of the film. In-plane retardation can be measured using a commercially available phase difference measuring apparatus (for example, “WPA-micro” manufactured by Photonic Lattice) or the Senarmon method. The measurement wavelength of in-plane retardation is 543 nm unless otherwise specified.

  The term “(meth) acrylate” includes both “acrylate” and “methacrylate”. Furthermore, “(meth) acryl” includes both “acryl” and “methacryl”.

“Ultraviolet light” means light having a wavelength of 1 nm or more and 400 nm or less.
The “visible light region” represents a wavelength range of 450 nm to 700 nm.

  Further, the angles of the optical axis of the optical element, such as the transmission axis of the polarizing plate and the slow axis of the retardation layer, mean angles as viewed from the thickness direction unless otherwise specified.

  Further, unless the direction of the component is “parallel” or “vertical”, it may include an error within a range that does not impair the effect of the present invention, for example, within a range of ± 5 °, unless otherwise specified.

[1. First embodiment]
FIG. 1 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to a first embodiment of the present invention. In the mode of use, the members constituting the liquid crystal display device are normally in contact with each other, but in FIG.

  As shown in FIG. 1, an in-vehicle liquid crystal display device 10 according to the first embodiment of the present invention includes an in-vehicle liquid crystal display element 100 and a light control element provided on a screen 121 of the liquid crystal display element 100. The cholesteric resin layer 210 is provided. The liquid crystal display element 100 includes a light source 110 and a liquid crystal panel 120.

  The liquid crystal panel 120 includes a light source side polarizing plate 130, a liquid crystal cell 140, and a viewing side polarizing plate 150 in the order closer to the light source 110.

Light-source polarization plate 130 is a linear polarizer having a transmission axis in the direction indicated by arrow A _130, it is possible to transmit linearly polarized light having a vibration direction in the direction indicated by arrow A _130, blocks the other polarization It has a configuration. Here, the vibration direction of linearly polarized light means the vibration direction of the electric field of linearly polarized light.

  The liquid crystal cell 140 is an optical element that includes a liquid crystal compound whose orientation can be changed according to a voltage applied from an electrode (not shown), and rotates linearly polarized light transmitted through the light source side polarizing plate 130 according to the applied voltage. It has a configuration that can be made.

The viewing-side polarizing plate 150 is a linear polarizing plate having a transmission axis in the direction indicated by the arrow A ₁₅₀ , and can transmit linearly polarized light having the vibration direction in the direction indicated by the arrow A ₁₅₀ , and can block other polarized light. It has a configuration. In this embodiment, the direction of the transmission axis of the viewing side polarizing plate 150 indicated by the arrow A ₁₅₀ and the direction of the transmission axis of the light source side polarizing plate 130 indicated by the arrow A ₁₃₀ are perpendicular to each other.

Furthermore, in this embodiment, the surface on the viewing side polarizing plate 150 side of the liquid crystal panel 120 forms the screen 121. Therefore, in the liquid crystal display element 100, light emitted from the light source 110 passes through the light source side polarizing plate 130, the liquid crystal cell 140, and the viewing side polarizing plate 150 in this order, and an image is displayed on the screen 121 by the transmitted light. It has the composition which is. Further, the liquid crystal display element 100 has a configuration capable of displaying an image displayed on the screen 121 by linearly polarized light having a vibration direction in a direction indicated by an arrow A ₁₅₀ .

  The cholesteric resin layer 210 as the light control element is a resin layer having cholesteric regularity. The cholesteric regularity of the cholesteric resin layer 210 means that the molecular axes are aligned in a certain direction on one plane, but the direction of the molecular axis is shifted at an angle in the next plane that overlaps it, and the next plane Then, as the angle is further shifted, the angle of the molecular axis in the plane is shifted (twisted) as it sequentially transmits through the overlapping planes. Thus, the structure in which the direction of the molecular axis is twisted becomes an optically chiral structure.

  The cholesteric resin layer 210 has a circularly polarized light separation function. That is, the cholesteric resin layer 210 has a property of transmitting one circularly polarized light of right circularly polarized light and left circularly polarized light and reflecting a part or all of the other circularly polarized light.

  The wavelength at which the cholesteric resin layer 210 exhibits the circularly polarized light separating function depends on the pitch of the helical structure in the cholesteric resin layer 210. The pitch of the helical structure is the distance in the plane normal direction until the angle of the molecular axis in the helical structure gradually shifts as it advances along the plane and then returns to the original molecular axis direction again. By changing the pitch of the helical structure, the wavelength at which the circularly polarized light separating function is exhibited can be changed. The cholesteric resin layer 210 capable of exhibiting a circularly polarized light separation function in a wide wavelength range includes, for example, (i) a cholesteric resin layer in which the pitch of the helical structure is changed stepwise, and (ii) a large pitch of the helical structure. Examples thereof include a cholesteric resin layer whose thickness is continuously changed. In the present embodiment, an example in which the cholesteric resin layer 210 has the circularly polarized light separation function in the visible light region will be described.

  In the cholesteric resin layer 210, the average value of the light transmittance in the visible light region falls within a predetermined range. That is, when non-polarized light enters the cholesteric resin layer 210 perpendicularly, the average value of the light transmittance in the non-polarized visible light region falls within a predetermined range. The specific range of the average value of the light transmittance in the visible light region is usually 60% or more, preferably 62% or more, more preferably 65% or more, and usually 75% or less, preferably 73% or less. Preferably it is 70% or less. The average value of the light transmittance in the visible light region of the cholesteric resin layer 210 can be adjusted by the thickness of the cholesteric resin layer 210, for example.

Since the cholesteric resin layer 210 has the average value of the light transmittance in the visible light region as described above, the light L that displays an image on the screen 121 of the liquid crystal display element 100 is perpendicular or perpendicular to the cholesteric resin layer 210. light L _F that passes in a direction close to the cholesteric resin layer 210, can be transmitted at a high average transmittance as the range. However, among the light L that displays an image on the screen 121 of the liquid crystal display element 100, the light L _{S that} is transmitted in an oblique direction with respect to the cholesteric resin layer 210 is cholesteric only with an average transmittance lower than the light L _F. The resin layer 210 cannot be transmitted. Such a difference in light transmittance depending on the transmission direction is considered to be caused by a shift in the reflection band, a change in polarization state, an increase in apparent thickness, and the like due to a difference in the light transmission direction.

FIG. 2 is a schematic diagram schematically showing a state in which the liquid crystal display device 10 according to the first embodiment of the present invention is provided in the vehicle 300.
As shown in FIG. 2, the liquid crystal display device 10 is usually provided on an instrument panel (not shown) of the vehicle 300. In this case, a user 310 such as a driver views the image displayed on the screen 121 by directly looking at the liquid crystal display device 10. Normally, the user 310 views the screen 121 from the front. Therefore, the user 310, of the light transmitted through the cholesteric resin layer 210 out of the screen 121, to visually recognize the light L _F that passes through in a direction nearly perpendicular or perpendicular to the cholesteric resin layer 210. Since the light L _F can transmit cholesteric resin layer 210 at a high average transmittance, the user 310 can clearly visually recognize the image displayed on a screen 121. Therefore, the visibility of the screen 121 is good.

In addition, out of the light that exits from the screen 121 and passes through the cholesteric resin layer 210, the light L _{S that} is transmitted in an oblique direction with respect to the cholesteric resin layer 210 is incident on the windshield 320 of the vehicle 300. reflect. If the intensity of the reflected light L _S is strong, this light L _S may cause reflection on the windshield 320. However, in the present embodiment, since the light L _S can only transmit through the cholesteric resin layer 210 with a low average transmittance, the user 310 cannot clearly see the image displayed by the light L _S. Therefore, the reflection of the video displayed on the screen 121 on the windshield 320 is suppressed.

  As described above, the liquid crystal display device 10 according to the first embodiment of the present invention has a relatively simple configuration in which the light transmittance is controlled within an appropriate range by adjusting the thickness of the cholesteric resin layer 210 or the like. The reflection on the windshield 320 can be suppressed without significantly impairing the visibility of the screen 121. Therefore, the user 310 is not hindered by the image reflected on the windshield 320 and can perform comfortable driving.

[2. Second embodiment]
In the first embodiment described above, the light control element is configured by only the cholesteric resin layer, but the light control element may be provided with a layer other than the cholesteric resin layer. For example, a retardation layer may be combined with the cholesteric resin layer. Hereinafter, such an example will be described as a second embodiment.

  FIG. 3 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to the second embodiment of the present invention. In the mode of use, the members constituting the liquid crystal display device are normally in contact with each other, but are shown in an exploded manner in FIG.

  As shown in FIG. 3, the in-vehicle liquid crystal display device 20 according to the second embodiment of the present invention has a retardation layer 420 provided on the viewing-side polarizing plate 150 side of the cholesteric resin layer 210, This is the same as the liquid crystal display device 10 according to the first embodiment. Therefore, the liquid crystal display device 20 includes the retardation layer 420 and the cholesteric resin layer 210 in this order from the side closer to the viewing-side polarizing plate 150 instead of using the cholesteric resin layer 210 alone as a light control element. It has the structure using.

  The retardation layer 420 is a layer having in-plane retardation that is uniform in the plane. The specific in-plane retardation of the retardation layer 420 according to this embodiment is a quarter wavelength. Here, the retardation layer 420 has an in-plane retardation of ¼ wavelength, and the in-plane retardation of the retardation layer 420 is usually ± from a value of ¼ of 543 nm which is the measurement wavelength. 65 nm, preferably ± 30 nm, more preferably ± 10 nm, or 3/4 of the central value, usually ± 65 nm, preferably ± 30 nm, more preferably ± 10 nm .

The retardation layer 420 is provided such that the transmission axis of the viewing-side polarizing plate 150 and the slow axis of the retardation layer 420 form an angle of approximately 45 °, as indicated by an arrow A ₄₂₀ . In the present embodiment, the slow axis of the retardation layer 420 forms the transmission axis of the viewing-side polarizing plate 150 when viewed in the direction in which the viewing-side polarizing plate 150 is in the back and the retardation layer 420 is in front. The angle is approximately 45 ° counterclockwise. Here, approximately 45 ° usually means 45 ° ± 5 °.

  Such a retardation layer 420 has a function of converting the polarization state of the light L transmitted through the viewing side polarizing plate 150 from linearly polarized light to circularly polarized light. The cholesteric resin layer 210 according to the present embodiment has a circularly polarized light separating function capable of transmitting the circularly polarized light transmitted through the retardation layer 420 and reflecting part or all of the circularly polarized light in the opposite direction. Is provided.

Thus, among the light L for displaying the image on the screen 121 of the liquid crystal display device 100, light L _F that passes through in a direction nearly perpendicular or perpendicular to the cholesteric resin layer 210 is a circle which can transmit cholesteric resin layer 210 Since it is polarized light or elliptically polarized light close thereto, it can be transmitted with a higher average transmittance than in the first embodiment. However, among the light L that displays an image on the screen 121 of the liquid crystal display element 100, the light L _{S that} is transmitted in an oblique direction with respect to the cholesteric resin layer 210 is cholesteric only with an average transmittance lower than the light L _F. The resin layer 210 cannot be transmitted. The difference in the light transmittance depending on the transmission direction is that the angle formed by the transmission axis of the viewing-side polarizing plate 150 and the slow axis of the retardation layer 420 apparently is approximately 45 ° in the light L _S transmitted in the oblique direction. This is probably because the polarization state of the light L _S transmitted through the retardation layer 420 is greatly separated from the circularly polarized light.

FIG. 4 is a schematic view schematically showing a state in which the liquid crystal display device 20 according to the second embodiment of the present invention is provided in the vehicle 300.
As shown in FIG. 4, the liquid crystal display device 20 is usually provided on an instrument panel (not shown) of the vehicle 300. In this case, as in the first embodiment, the user 310 sees the light L _F that passes through the light control element 400 in a direction nearly perpendicular or perpendicular to the cholesteric resin layer 210, the image displayed on the screen 121 Visually check. In the present embodiment, since the light L _F is transmitted through the cholesteric resin layer 210 with a high average transmittance than the embodiment, the user 310 can particularly clearly visible image on the screen 121, screen 121 The visibility of is good.

Further, similarly to the first embodiment, the light L _S transmitted through the light control element 400 in an oblique direction with respect to the cholesteric resin layer 210 may cause reflection on the windshield 320. However, in the present embodiment, since the light L _S can pass through the cholesteric resin layer 210 only with a low average transmittance, the user 310 cannot clearly see the image displayed by the light L _S , and the screen 121 The reflection of the image displayed on the windshield 320 is suppressed.

As described above, the liquid crystal display device 20 according to the second embodiment of the present invention can suppress the reflection on the windshield 320 without greatly impairing the visibility of the screen 121 while having a relatively simple configuration. . In particular, since it is improved than that of the liquid crystal display device 10 according to the intensity of the light L _F that passes through the light control element 400 in a vertical or almost vertical direction to the first embodiment, the user 310 is directly viewed LCD device 20 In particular, the visibility of the video can be improved.
Moreover, according to the liquid crystal display device 20 which concerns on 2nd embodiment of this invention, the same advantage as the liquid crystal display device 10 which concerns on 1st embodiment of this invention can be acquired.

[3. Third embodiment]
The light control element may include an arbitrary layer on the side (viewer side) opposite to the viewing side polarizing plate of the cholesteric resin layer. Examples of the optional layer include an antireflection layer and a hard coat layer. Hereinafter, such an example will be described as a third embodiment.

  FIG. 5 is an exploded perspective view schematically showing an in-vehicle liquid crystal display device according to the third embodiment of the present invention. In the mode of use, the members constituting the liquid crystal display device are usually in contact with each other, but are shown in an exploded manner in FIG.

  As shown in FIG. 5, the liquid crystal display device 30 shown in this example has a hard coat layer 530 and an antireflection layer 540 provided on the opposite side of the cholesteric resin layer 210 from the viewing side polarizing plate 150, This is the same as the liquid crystal display device 20 according to the second embodiment. Therefore, the liquid crystal display device 30 includes a retardation layer 420, a cholesteric resin layer 210, a hard coat layer 530, and an antireflection layer 540 instead of the light control element 400 in this order from the side closer to the viewing side polarizing plate 150. The control element 500 is used.

  The hard coat layer 530 is a layer having high hardness. Specifically, the hard coat layer 530 preferably exhibits a hardness of 1H or higher, preferably 4H or higher, in a pencil hardness test (test plate is a glass plate) shown in JIS K5600-5-4. Thereby, damage to the light control element 500 can be prevented.

  The antireflection layer 540 is a layer for preventing reflection of external light. In order to prevent reflection of external light, the antireflection layer 540 preferably has a refractive index smaller than that of the hard coat layer 530. Specifically, the hard coat layer 530 preferably has a refractive index of 1.60 to 1.70, and the antireflection layer 540 preferably has a refractive index of less than 1.40. More specifically, the refractive index of the antireflection layer 540 is preferably 1.25 or more, more preferably 1.30 or more, preferably 1.39 or less, more preferably 1.38 or less.

Although the liquid crystal display device 30 according to the third embodiment of the present invention has a relatively simple configuration, the antireflection layer 540 can prevent reflection of external light, so that reflection of external light on the screen 121 can be prevented. . Therefore, since the user of the vehicle can visually recognize the image on the screen 121 without hindering the reflection of external light, the visibility can be further improved.
Further, according to the liquid crystal display device 30 according to the third embodiment of the present invention, the same advantages as those of the liquid crystal display device 20 according to the second embodiment of the present invention can be obtained.

[4. Modified example]
The present invention is not limited to the embodiment described above, and may be further modified.
For example, an arbitrary layer other than those described above may be provided on the liquid crystal display element and the light control element. Specific examples of such an arbitrary layer include an adhesive layer, an antifouling layer, and a gas barrier layer.
Further, as long as a desired image can be appropriately displayed, the direction of the optical axis such as the slow axis and the transmission axis of each optical element may be changed.

  Further, when the slow axis of the retardation layer forms an angle of about 45 ° clockwise or counterclockwise with respect to the transmission axis of the viewing side polarizing plate, the linearly polarized light transmitted through the viewing side polarizing plate becomes circularly polarized light. Can be converted. Therefore, there is a case where the slow axis of the retardation layer forms an angle of about 45 ° in the opposite direction to the slow axis of the retardation layer 420 according to the above embodiment with respect to the transmission axis of the viewing side polarizing plate. By passing through the retardation layer, linearly polarized light can be converted into circularly polarized light. In this case, the direction of the circularly polarized light that can be reflected by the cholesteric resin layer can be appropriately set so that the average value of the light transmittance in the visible light region of the light control element is within the above-described range.

[5. Material etc.]
Hereinafter, the material and manufacturing method of the layer provided in the light control element described above will be described.

[5.1. Cholesteric resin layer]
The cholesteric resin layer can be obtained, for example, by providing a film of a photocurable liquid crystal composition on a substrate film and curing the film of the liquid crystal composition. In this case, as the liquid crystal composition, for example, a composition containing a liquid crystal compound and capable of exhibiting a cholesteric liquid crystal phase when a film is formed on the base film can be used.

  Here, as the liquid crystal compound contained in the liquid crystal composition, a polymerizable liquid crystal compound can be used. A non-liquid crystalline cholesteric resin layer cured by polymerizing the liquid crystalline compound having such polymerizability in a state exhibiting cholesteric regularity to cure the film of the liquid crystal composition and exhibiting cholesteric regularity. Can be obtained.

  Preferred examples of such a liquid crystal composition include a liquid crystal composition containing a compound represented by the following formula (1) and a specific rod-like liquid crystal compound.

R ¹ -A ¹ -BA ² -R ² (1)
In the formula (1), R ¹ and R ² are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, or a straight chain having 1 to 20 carbon atoms. Or a branched alkylene oxide group, a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, which may have an arbitrary linking group interposed, And a group selected from the group consisting of a cyano group.

  The alkyl group and alkylene oxide group may be unsubstituted or substituted with one or more halogen atoms. Furthermore, the halogen atom, hydroxyl group, carboxyl group, (meth) acryl group, epoxy group, mercapto group, isocyanate group, amino group, and cyano group are alkyl groups having 1 to 2 carbon atoms, and alkylene oxide. It may be bonded to a group.

Preferred examples of R ¹ and R ² include a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

Moreover, it is preferable that at least one of R ¹ and R ² is a reactive group. By having a reactive group as at least one of R ¹ and R ^2, the compound represented by the formula (1) is fixed in the cholesteric resin layer at the time of curing, and a stronger layer can be formed. Here, examples of the reactive group include a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group.

In the formula (1), A ¹ and A ² are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4, It represents a group selected from the group consisting of a 4′-bicyclohexylene group and a 2,6-naphthylene group. The 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4,4′-bicyclohexylene group, and 2,6-naphthylene group are Are not substituted, or are substituted with one or more substituents such as a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkyl group having 1 to 10 carbon atoms, and a halogenated alkyl group. May be. In each of A ¹ and A ² , when two or more substituents are present, they may be the same or different.

Particularly preferred examples of A ¹ and A ² include groups selected from the group consisting of 1,4-phenylene group, 4,4′-biphenylene group, and 2,6-naphthylene group. These aromatic ring skeletons are relatively rigid as compared with the alicyclic skeletons, have high affinity with the mesogen of the rod-like liquid crystal compound, and higher alignment uniformity.

In the formula (1), B represents a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH. = N-N = CH -, - NHCO -, - O- (C = O) -O -, - CH 2 - (C = O) -O-, and _{-CH 2 O- (C = O)} - from the Selected from the group consisting of
Particularly preferable examples of B include a single bond, —O— (C═O) —, and —CH═N—N═CH—.

  At least one of the compounds represented by the formula (1) preferably has liquid crystallinity, and preferably has chirality. In addition, the compound represented by the formula (1) is preferably used in combination of a plurality of optical isomers. For example, a mixture of a plurality of types of enantiomers, a mixture of a plurality of types of diastereomers, or a mixture of enantiomers and diastereomers may be used. At least one of the compounds represented by formula (1) preferably has a melting point in the range of 50 ° C to 150 ° C.

  When the compound represented by the formula (1) has liquid crystallinity, the refractive index anisotropy Δn is preferably high. By using a liquid crystalline compound having a high refractive index anisotropy Δn as the compound represented by the formula (1), the refractive index anisotropy Δn of a liquid crystal composition containing the compound can be improved, and circularly polarized light is reflected. A cholesteric resin layer having a wide possible wavelength range can be produced. The refractive index anisotropy Δn of the compound represented by the formula (1) is preferably 0.18 or more, more preferably 0.22 or more. Here, the refractive index anisotropy Δn can be measured by the Senarmon method. For example, the cured resin layer is extinguished using an optical microscope (ECLIPSE E600POL (transmission / reflection type) with a sensitive color plate, quarter wavelength plate, Senarmon compensator, GIF filter 546 nm, manufactured by Nikon Corporation). In-plane retardation (Re) is calculated from the equation of Re = λ (546 nm) × θ / 180, and Δn is calculated from the thickness (d) of the liquid crystal layer obtained separately by the equation Δn = Re / d. It can be calculated.

  Specific examples of particularly preferred compounds represented by the formula (1) include the following compounds (A1) to (A9). Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  In the compound (A3), “*” represents a chiral center.

As the rod-like liquid crystalline compound that can be used in combination with the compound represented by the formula (1), a rod-like liquid crystalline compound having at least two or more reactive groups in one molecule can be used. An example of such a rod-like liquid crystalline compound is a compound represented by the formula (2).
^{R 3 -C 3 -D 3 -C 5} -M-C 6 -D 4 -C 4 -R 4 Formula (2)

In the formula (2), R ³ and R ⁴ are reactive groups, each independently (meth) acryl group, (thio) epoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, vinyl group. , An allyl group, a fumarate group, a cinnamoyl group, an oxazoline group, a mercapto group, an iso (thio) cyanate group, an amino group, a hydroxyl group, a carboxyl group, and an alkoxysilyl group. By having these reactive groups, a cured product having a film strength that can withstand practical use can be obtained when the liquid crystal composition is cured. Here, the film strength that can withstand practical use is pencil hardness (JIS K5400), which is usually HB or higher, preferably H or higher. By increasing the film strength in this way, it is difficult to damage the film, so that handling properties can be improved.

In Formula (2), D ³ and D ⁴ are a single bond, a linear or branched alkyl group having 1 to 20 carbon atoms, and a linear or branched chain group having 1 to 20 carbon atoms, or Represents a group selected from the group consisting of branched alkylene oxide groups.

In the formula (2), C ^{3 to} C ⁶ are a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH _2. -, - CH = N-N = CH -, - NHCO -, - O- (C = O) -O -, - CH 2 - (C = O) -O-, and -CH ₂ O- (C = Represents a group selected from the group consisting of O)-.

In the formula (2), M represents a mesogenic group. Specifically, M is an azomethine group, azoxy group, phenyl group, biphenyl group, terphenyl group, naphthalene group, anthracene group, benzoic acid ester group, cyclohexanecarboxyl group, which may be unsubstituted or substituted. 2-4 skeletons selected from the group of acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles, O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH═N—N═CH—, —NHCO—, — O- (C = O) -O - , - CH 2 - (C = O) -O-, and _{-CH 2 O- (C = O)} - represents a group bonded through by a linking group such as

Examples of the substituent that the mesogenic group M may have include a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, —O—R ⁵ , — O—C (═O) —R ⁵ , —C (═O) —O—R ⁵ , —O—C (═O) —O—R ⁵ , —NR ⁵ —C (═O) —R ⁵ , -C (= O) -NR < ⁵ > R < ⁷ > or -O-C (= O) -NR < ⁵ > R < ⁷ > is mentioned. Wherein, R ⁵ and ^{R 7} represents a hydrogen atom or a C 1 to 10 alkyl group carbon. When R ⁵ and R ⁷ are alkyl groups, the alkyl groups include —O—, —S—, —O—C (═O) —, —C (═O) —O—, —O—C. (═O) —O—, —NR ⁶ —C (═O) —, —C (═O) —NR ⁶ —, —NR ⁶ —, or —C (═O) — may be present. (However, the case where two or more of -O- and -S- are adjacent to each other is excluded). Here, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

  Examples of the substituent in the “optionally substituted alkyl group having 1 to 10 carbon atoms” include, for example, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, and a carbon atom number of 1 to 6 alkoxy groups, alkoxyalkoxy groups having 2 to 8 carbon atoms, alkoxyalkoxyalkoxy groups having 3 to 15 carbon atoms, alkoxycarbonyl groups having 2 to 7 carbon atoms, and 2 carbon atoms A 7 to 7 alkylcarbonyloxy group, an alkoxycarbonyloxy group having 2 to 7 carbon atoms, and the like.

The rod-like liquid crystalline compound preferably has an asymmetric structure. Here, the asymmetric structure is a structure in which R ³ -C ³ -D ³ -C ⁵ -and -C ⁶ -D ⁴ -C ⁴ -R ⁴ are different in the formula (2) with the mesogenic group M as the center. Say. By using a rod-shaped liquid crystalline compound having an asymmetric structure, alignment uniformity can be further improved.

  The refractive index anisotropy Δn of the rod-like liquid crystal compound is preferably 0.18 or more, more preferably 0.22 or more. When a rod-like liquid crystalline compound having a refractive index anisotropy Δn of 0.30 or more is used, the absorption edge on the long wavelength side of the ultraviolet absorption spectrum of the rod-like liquid crystalline compound may extend to the visible region. Can be used as long as they do not adversely affect the desired optical performance even in the visible range. By using such a rod-like liquid crystalline compound having a high refractive index anisotropy Δn, a cholesteric resin layer having high optical performance (for example, selective reflection performance of circularly polarized light) can be obtained.

  Preferable specific examples of the rod-like liquid crystalline compound include the following compounds (B1) to (B9). Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  The weight ratio represented by (total weight of compounds represented by formula (1)) / (total weight of rod-like liquid crystalline compounds) is preferably 0.05 or more, more preferably 0.1 or more, and particularly preferably 0. .15 or more, preferably 1 or less, more preferably 0.65 or less, and particularly preferably 0.45 or less. By setting the weight ratio to be equal to or higher than the lower limit of the range, it is possible to improve alignment uniformity in the liquid crystal composition film. Further, by setting the upper limit value or less, the alignment uniformity can be increased. In addition, the stability of the liquid crystal phase of the liquid crystal composition can be increased. Furthermore, since the refractive index anisotropy Δn of the liquid crystal composition can be increased, a cholesteric resin layer having desired optical performance (for example, selective reflection performance of circularly polarized light) can be stably obtained. Here, the total weight indicates the weight when one type is used, and indicates the total weight when two or more types are used.

  Moreover, when using the compound represented by Formula (1) and a rod-shaped liquid crystalline compound in combination, it is preferable that the molecular weight of the compound represented by Formula (1) is less than 600, and the molecular weight of a rod-shaped liquid crystalline compound is It is preferable that it is 600 or more. Thereby, since the compound represented by Formula (1) can enter into the gaps between the rod-like liquid crystal compounds having a higher molecular weight than that, the alignment uniformity can be improved.

  The liquid crystal composition may contain a crosslinking agent in order to improve the mechanical strength and durability of the cured product film. The cross-linking agent increases the cross-linking density of the cured product film, for example, by reacting when the film of the liquid crystal composition is cured, promoting the reaction by heat treatment after curing, or allowing the reaction to proceed spontaneously due to moisture. be able to. As a crosslinking agent, what can react with an ultraviolet-ray, a heat | fever, humidity, etc. can be used, for example. Among these, as the crosslinking agent, those that do not deteriorate the alignment uniformity are preferable.

  Examples of the crosslinking agent include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2- (2-vinyloxyethoxy). Polyfunctional acrylate compounds such as ethyl acrylate; Epoxy compounds such as glycidyl (meth) acrylate, ethylene glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether; 2,2-bishydroxymethylbutanol-tris [3- ( 1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane, trimethylolpropane-tri-β-aziridinylpropionate Aziridine compounds such as onate; Isocyanurate type isocyanate derived from hexamethylene diisocyanate, hexamethylene diisocyanate, biuret type isocyanate, adduct type isocyanate, etc .; Polyoxazoline compound having an oxazoline group in the side chain; Vinyltrimethoxysilane; N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, N- (1 , 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine and the like alkoxysilane compounds. Moreover, a crosslinking agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Furthermore, you may use a well-known catalyst according to the reactivity of a crosslinking agent. By using the catalyst, productivity can be improved in addition to the improvement of the film strength and durability of the cholesteric resin layer.

  The amount of the crosslinking agent is preferably such that the amount of the crosslinking agent in the cholesteric resin layer obtained by curing the film of the liquid crystal composition is 0.1% by weight to 15% by weight. By setting the amount of the crosslinking agent to be not less than the lower limit of the above range, the crosslinking density can be effectively increased. Moreover, the stability of the film | membrane of a liquid-crystal composition can be improved by making it into an upper limit or less.

  Moreover, since a liquid crystal composition has photocurability, it usually contains a photoinitiator. As a photoinitiator, the well-known compound which generate | occur | produces a radical or an acid with an ultraviolet-ray or visible light can be used, for example. Specific examples of the photoinitiator include benzoin, benzylmethyl ketal, benzophenone, biacetyl, acetophenone, Michler's ketone, benzyl, benzylisobutyl ether, tetramethylthiuram mono (di) sulfide, 2,2-azobisisobutyronitrile, 2 , 2-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, di-tert-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, methylbenzoylformate, , 2-diethoxyacetophenone, β-ionone, β-bromostyrene, diazoaminobenzene, α-amylcinnackaldehyde, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, pp′-dichloro Benzophenone, pp'-bisdiethylaminobenzophenone, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin n-butyl ether, diphenyl sulfide, bis (2,6-methoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide 2-Methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, anthracene Benzophenone, α-chloroanthraquinone, diphenyl disulfide, hexachlorobutadiene, pentachlorobutadiene, octachlorobutene, 1-chloromethylnaphthalene, 1,2-octanedione-1- [4- (phenylthio) -2- (o-benzoyl) Oxime)] or 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (o-acetyloxime), (4-methylphenyl) [ 4- (2-Methylpropyl) phenyl] iodonium hexafluorophor Feto, 3-methyl-2-butynyl tetramethyl hexafluoroantimonate, diphenyl - (p-phenylthiophenyl) sulfonium hexafluoroantimonate, and the like. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Furthermore, you may control sclerosis | hardenability using the tertiary amine compound as a well-known photosensitizer or a polymerization accelerator as needed.

  The amount of the photoinitiator is preferably 0.03% to 7% by weight in the liquid crystal composition. By setting the amount of the photoinitiator to be equal to or higher than the lower limit of the above range, the degree of polymerization can be increased, so that the film strength of the cholesteric resin layer can be increased. Moreover, since the orientation of a liquid crystalline compound can be made favorable by setting it to the upper limit value or less, the liquid crystal phase of the liquid crystal composition can be stabilized.

  The liquid crystal composition can optionally contain a surfactant. As the surfactant, for example, one that does not inhibit the orientation can be appropriately selected and used. As such a surfactant, for example, a nonionic surfactant containing a siloxane or a fluorinated alkyl group in the hydrophobic group portion is preferably exemplified. Of these, oligomers having two or more hydrophobic group moieties in one molecule are particularly suitable. Specific examples of these surfactants include PolyFox PF-151N, PF-636, PF-6320, PF-656, PF-6520, PF-3320, PF-651, PF-652 from OMNOVA; Neos FTX-209F, FTX-208G, FTX-204D of Surfacton, KH-40 of Surflon of Seimi Chemical Co., etc. can be used. Moreover, surfactant may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  The amount of the surfactant is preferably such that the amount of the surfactant in the cholesteric resin layer obtained by curing the liquid crystal composition is 0.05% by weight to 3% by weight. By setting the amount of the surfactant to be equal to or higher than the lower limit of the above range, the alignment regulating force at the air interface can be increased, so that alignment defects can be prevented. Moreover, by making it into the upper limit value or less, it is possible to prevent a decrease in alignment uniformity due to excessive surfactant entering between liquid crystal molecules.

  The liquid crystal composition can optionally contain a chiral agent. Usually, the twist direction of the cholesteric resin layer can be appropriately selected depending on the type and structure of the chiral agent to be used. This can be realized by using a chiral agent that imparts dextrorotability when the twist is in the right direction, and by using a chiral agent that imparts levorotation when the twist direction is in the left direction. Specific examples of the chiral agent include JP-A-2005-289881, JP-A-2004-115414, JP-A-2003-66214, JP-A-2003-313187, JP-A-2003-342219, JP-A-2003-342219. 2000-290315, JP-A-6-072962, U.S. Pat. No. 6,468,444, WO 98/00428, JP-A 2007-176870, etc. can be used as appropriate. For example, it is available as LC756 of BASF Corporation Paliocolor. Moreover, a chiral agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The amount of the chiral agent can be arbitrarily set within a range not deteriorating the desired optical performance. The specific amount of the chiral agent is usually 1% by weight to 60% by weight in the liquid crystal composition.

  The liquid crystal composition may further contain optional components as necessary. Examples of the optional component include a solvent, a polymerization inhibitor for improving pot life, an antioxidant for improving durability, an ultraviolet absorber, and a light stabilizer. Moreover, these arbitrary components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. The amount of these optional components can be arbitrarily set within a range that does not deteriorate the desired optical performance.

  The manufacturing method of a liquid crystal composition is not specifically limited, It can manufacture by mixing said each component.

  After preparing the photocurable liquid crystal composition, a film of the liquid crystal composition is provided on the base film. Usually, a film of a liquid crystal composition is provided by applying the liquid crystal composition to the surface of a base film.

  In addition, an alignment film may be provided on the base film before providing the liquid crystal composition film. The alignment film can be formed of a resin containing a polymer such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, polyetherimide, polyamide, and the like. Moreover, these polymers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. The alignment film can be produced, for example, by applying a solution containing the above polymer, drying, and performing a rubbing treatment. The thickness of the alignment film is preferably 0.01 μm or more, more preferably 0.05 μm or more, preferably 5 μm or less, more preferably 1 μm or less. When the base film has an alignment film, a liquid crystal composition film is usually provided on the alignment film.

  Furthermore, before applying the liquid crystal composition, a surface treatment such as a corona discharge treatment or a rubbing treatment may be applied to the surface of the base film as necessary.

  The liquid crystal composition can be applied by a known method such as extrusion coating, direct gravure coating, reverse gravure coating, die coating, or bar coating.

  After providing a film of the liquid crystal composition on the base film, an alignment treatment may be performed as necessary. The alignment treatment can be performed, for example, by heating a liquid crystal composition film at 50 to 150 ° C. for 0.5 to 10 minutes. By performing the alignment treatment, the liquid crystal composition in the film can be aligned well.

Thereafter, a curing process is performed to cure the film of the liquid crystal composition. The curing process can be performed, for example, by a combination of one or more light irradiations and a heating process.
The heating conditions are, for example, usually 40 ° C. or higher, preferably 50 ° C. or higher, and usually 200 ° C. or lower, preferably 140 ° C. or lower, usually 1 second or longer, preferably 5 seconds or longer, and usually 3 minutes. Hereinafter, the time may be preferably 120 seconds or less.
Moreover, the light used for light irradiation includes not only visible light but also ultraviolet rays and other electromagnetic waves. Light irradiation can be performed by, for example, irradiating light having a wavelength of 200 nm to 500 nm for 0.01 second to 3 minutes. At this time, the energy of light irradiated, for ^example, may be a ^{0.01mJ / cm 2 ~50mJ / cm 2} .

By repeating 0.01mJ ^/ cm ² ~50mJ / cm 2 of weak ultraviolet irradiation and heating Metropolitan several times alternately, the size of the pitch of the helical structure continuously largely changed, a wide circle of reflection band A cholesteric resin layer having a polarization separation function can be obtained. Further, after the extension of the reflection band by weak ultraviolet irradiation, or the like described ^above was irradiated with a relatively strong ultraviolet such ^{50mJ / cm 2 ~10,000mJ / cm 2} , by completely polymerizing the liquid crystalline compounds, A cholesteric resin layer having high mechanical strength can be obtained. The expansion of the reflection band and the irradiation with strong ultraviolet rays may be performed in the air, or a part or all of the process may be performed in an atmosphere in which the oxygen concentration is controlled (for example, in a nitrogen atmosphere).

  The steps of applying and curing the liquid crystal composition as described above are not limited to once, and application and curing may be repeated a plurality of times. Thereby, the cholesteric resin layer containing two or more layers can be formed. However, by using the liquid crystal composition described in the above example, a cholesteric resin layer containing a well-oriented rod-like liquid crystalline compound and having a thickness of 5 μm or more can be obtained by applying and curing the liquid crystal composition only once. Can be easily formed.

  The thickness of the cholesteric resin layer is preferably 5 μm or less from the viewpoint of keeping the average transmittance in the visible light range within the above range. More specifically, the thickness of the cholesteric resin layer is preferably 1.0 μm or more, more preferably 1.5 μm or more, particularly preferably 2.0 μm or more, preferably 5 μm or less, more preferably 4.7 μm or less, particularly Preferably it is 4.5 micrometers or less.

[5.2. Retardation layer]
For the retardation layer, for example, a stretched film formed of a resin can be used. Typically, the resin includes a polymer. Examples of the polymer contained in the resin that is the material of the retardation layer include chain olefin polymer, cycloolefin polymer, polycarbonate, polyester, polysulfone, polyethersulfone, polystyrene, polyvinyl alcohol, cellulose acetate polymer, polyvinyl chloride, Examples include polymethacrylate. Among these, a chain olefin polymer and a cycloolefin polymer are preferable, and a cycloolefin polymer is particularly preferable from the viewpoint of transparency, low hygroscopicity, dimensional stability, lightness, and the like. Moreover, what contains one type of polymer independently may be used for resin, and what contains combining 2 or more types of polymers by arbitrary ratios may be used for it.
Moreover, unless the effect of this invention is impaired remarkably, you may include arbitrary compounding agents in resin.
Furthermore, as the retardation layer, a single layer structure film or a multilayer structure film may be used.
When the example of a suitable phase difference layer is given, a commercially available long diagonally stretched film, a laterally stretched film, etc. will be mentioned. Specific examples thereof include the product names “obliquely stretched ZEONOR film” and “laterally stretched ZEONOR film” manufactured by ZEON Corporation.

[5.3. Antireflection layer]
Examples of the material for the antireflection layer include: a resin material such as an ultraviolet curable acrylic resin; a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin; a sol using a metal alkoxide such as tetraethoxysilane; Gel-based materials; and the like. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Further, as the antireflection layer, for example, those described in Japanese Patent No. 4556613, Japanese Patent No. 4300522 and Japanese Patent No. 4556664 may be used.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.
In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. Moreover, the following operation was performed in normal temperature normal pressure atmosphere unless otherwise indicated. Further, in the following description, an angle formed by the optical axis represents an angle in a direction in which the screen of the liquid crystal display element is viewed from the front unless otherwise specified.

[Measurement method of light transmittance of cholesteric resin layer]
The light transmittance of the cholesteric resin layer was measured using a transmittance meter (“V-7200” manufactured by JASCO Corporation).

[Production Example 1]
(1-1. Production of liquid crystal composition)
Reagents were mixed in the proportions shown in Table 1 below to produce a liquid crystal composition for forming a cholesteric resin layer.

The contents of each reagent shown in Table 1 are as follows.
Chiral agent: “LC756” manufactured by BASF
Photopolymerization initiator: “Irgacure 907” manufactured by Ciba Japan
Surfactant: Neos "Factent 209F"

  Furthermore, the molecular structures of the photopolymerizable liquid crystal compound 1 and the photopolymerizable non-liquid crystal compound shown in Table 1 are as follows.

(1-2. Production of cholesteric resin layer)
A long polyethylene terephthalate film (“PET film A4100” manufactured by Toyobo Co., Ltd .; thickness 100 μm) having an in-plane refractive index isotropic and having an in-plane refractive index was prepared as a base film. One surface of this base film was rubbed. Next, the prepared liquid crystal composition was apply | coated to the surface which gave the rubbing process using the die-coater. Thereby, the film | membrane of the uncured liquid crystal composition was formed in the single side | surface of a base film.

The obtained liquid crystal composition film was subjected to an alignment treatment at 100 ° C. for 5 minutes. Thereafter, the film was cooled to 25 ° C., and the process consisting of irradiation treatment with weak ultraviolet rays of 10 mJ / cm ² and subsequent heating treatment at 100 ° C. for 1 minute was repeated twice in the air atmosphere. . Thereafter, the liquid crystal composition film was irradiated with ultraviolet rays of 800 mJ / cm ² in a nitrogen atmosphere to completely cure the liquid crystal composition film. As a result, a cholesteric resin layer having a thickness of 4.7 μm was formed on one surface of the base film to obtain a multilayer film including the base film and the cholesteric resin layer.
When the average value of the light transmittance of the cholesteric resin layer in the wavelength range of 450 nm to 700 nm was measured, it was about 61%.

[Production Example 2]
A multilayer film provided with a base film and a cholesteric resin layer was obtained in the same manner as in Production Example 1 except that the thickness of the cholesteric resin layer was 3.0 μm.
The average value of light transmittance in the wavelength range of 450 nm to 700 nm of this cholesteric resin layer was 73%.

[Production Example 3]
A multilayer film including a base film and a cholesteric resin layer was obtained in the same manner as in Production Example 1 except that the thickness of the cholesteric resin layer was set to 5.2 μm.
The average value of light transmittance in the wavelength range of 450 nm to 700 nm of this cholesteric resin layer was 55%.

[Example 1]
A liquid crystal display element having a light source, a light source side polarizing plate, a liquid crystal cell, and a viewing side polarizing plate in this order (“LCD-AD201XGB” manufactured by IO-DATA; TN type liquid crystal panel “MT200LW01” manufactured by Innolux) is provided). Prepared.

  An acrylic pressure-sensitive adhesive (“Non-Carrier TD06A” manufactured by Yodogawa Paper Co., Ltd.) with a thickness of 25 μm was applied to the surface of the prepared liquid crystal display element opposite to the liquid crystal cell of the viewing side polarizing plate to form an adhesive layer. After the multi-layer film produced in Production Example 1 was bonded to the adhesive layer on the surface on the cholesteric resin layer side, the base film was peeled from the cholesteric resin layer. Thereby, the liquid crystal display device provided with a light source, a light source side polarizing plate, a liquid crystal cell, a visual recognition side polarizing plate, and a cholesteric resin layer in this order was obtained.

This liquid crystal display device was arranged at the center of the instrument panel of the vehicle in such a direction that the transmission axis of the viewing side polarizing plate forms an angle of 135 ° counterclockwise with respect to the horizontal direction (0 ° direction).
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver's seat, front passenger seat and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was significantly reduced from any viewpoint. Further, when the screen of the liquid crystal display device was directly observed, there was almost no decrease in visibility.

[Example 2]
A liquid crystal display device was manufactured in the same manner as in Example 1 except that the multilayer film manufactured in Manufacturing Example 2 was used instead of the multilayer film manufactured in Manufacturing Example 1. Placed in the department.
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver's seat, front passenger seat and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was reduced from any viewpoint. Further, when the screen of the liquid crystal display device was directly observed, there was almost no decrease in visibility.

[Example 3]
A liquid crystal display element similar to that of Example 1 was prepared. An acrylic pressure-sensitive adhesive (“Non-Carrier TD06A” manufactured by Yodogawa Paper Co., Ltd.) with a thickness of 25 μm was applied to the surface of the prepared liquid crystal display element opposite to the liquid crystal cell of the viewing side polarizing plate to form an adhesive layer. A retardation film (“Horizontal stretched ZEONOR film” manufactured by Nippon Zeon Co., Ltd .; in-plane retardation 140 nm) was bonded to the adhesive layer as a retardation layer. At this time, the retardation axis of the retardation film was bonded in a direction that forms an angle of 45 ° counterclockwise with respect to the transmission axis of the viewing side polarizing plate. Furthermore, the said adhesive was apply | coated to the surface of this retardation film, and the adhesion layer was formed. The multilayer film produced in Production Example 2 was bonded to the adhesive layer on the surface on the cholesteric resin layer side, and then the base film was peeled from the cholesteric resin layer. Thereby, the liquid crystal display device provided with a light source, a light source side polarizing plate, a liquid crystal cell, a visual recognition side polarizing plate, a retardation film and a cholesteric resin layer in this order was obtained.

In this liquid crystal display device, the transmission axis of the viewing side polarizing plate forms an angle of 135 ° counterclockwise with respect to the horizontal direction (0 ° direction), and the slow axis of the retardation film is parallel to the horizontal direction. It was arranged in the center of the instrument panel of the vehicle.
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver's seat, front passenger seat and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was reduced from any viewpoint. Further, when the screen of the liquid crystal display device was directly observed, there was no degradation in visibility.

[Example 4]
(4-1. Production of hard coat layer forming material)
30 parts of a hexafunctional urethane acrylate oligomer, 40 parts of butyl acrylate, 30 parts of isoboronyl methacrylate, and 10 parts of 2,2-diphenylethane-1-one were mixed with a homogenizer to obtain a mixed solution. In this mixed solution, a 40% methyl isobutyl ketone solution of antimony pentoxide fine particles is mixed in an amount so that the weight of the antimony pentoxide fine particles is 50% by weight of the total solid content of the hard coat layer forming material, and the hard coat layer is mixed. A forming material was produced. The antimony pentoxide fine particles have an average particle diameter of 20 nm, and one hydroxyl group is bonded to each antimony atom appearing on the surface of the pyrochlore structure of antimony pentoxide.

(4-2. Production of material for forming low refractive index layer)
A solution was obtained by dissolving 70 parts by weight of vinylidene fluoride as a fluorine-containing monomer and 30 parts by weight of tetrafluoroethylene in methyl isobutyl ketone. Next, to this solution, 100 parts by weight of the solid content of the fluorine-containing monomer, isopropanol dispersion sol of hollow silica (manufactured by Catalyst Kasei Kogyo Co., Ltd., solid content of 20% by weight, average primary particle diameter of about 35 nm, outer shell thickness of about 8 nm) as a solid content of hollow silica, 30 parts by weight, 3 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Etsu Chemical Co., Ltd.), 5 parts by weight of a photo radical generator (“Irgacure 184” manufactured by Ciba Specialty Chemicals), Each was added to produce a material for forming a low refractive index layer.

(4-3. Manufacture of liquid crystal display device)
In the multilayer film produced in Production Example 2, the base film was peeled from the cholesteric resin layer. Thereafter, the surface of the cholesteric resin layer was subjected to corona discharge treatment. On the surface subjected to the corona discharge treatment, a hard coat layer forming material was applied using a die coater in an environment of a temperature of 25 ° C. and a humidity of 60% RH, and dried in an oven at 80 ° C. for 5 minutes. A film was formed. The film was irradiated with ultraviolet rays at an integrated dose of 300 mJ / cm ² to form a hard coat layer having a thickness of 6 μm. The refractive index of this hard coat layer was 1.62. Further, the pencil hardness of the surface of the hard coat layer exceeded 4H.

  Next, the material for forming the low refractive index layer was applied to the surface of the hard coat layer using a wire bar coater in an environment of a temperature of 25 ° C. and a humidity of 60% RH, and left to dry for 1 hour to form a coating film. Formed. This film was heat-treated at 120 ° C. for 10 minutes in an oxygen atmosphere, and then irradiated with ultraviolet rays under the conditions of an output of 160 W / cm and an irradiation distance of 60 mm, and a low refractive index layer (refractive index having a thickness of 100 nm as an antireflection layer). 1.37) was formed. Thereby, the multilayer film provided with a cholesteric resin layer, a hard-coat layer, and a low-refractive-index layer in this order was obtained.

  A liquid crystal display element similar to that of Example 1 was prepared. An acrylic pressure-sensitive adhesive (“Non-Carrier TD06A” manufactured by Yodogawa Paper Co., Ltd.) with a thickness of 25 μm was applied to the surface of the prepared liquid crystal display element opposite to the liquid crystal cell of the viewing side polarizing plate to form an adhesive layer. The multilayer film produced in Example 4 was bonded to the adhesive layer on the cholesteric resin layer side, and the light source, light source side polarizing plate, liquid crystal cell, viewing side polarizing plate, cholesteric resin layer, hard coat layer and low A liquid crystal display device having a refractive index layer in this order was obtained.

This liquid crystal display device was arranged at the center of the instrument panel of the vehicle in such a direction that the transmission axis of the viewing side polarizing plate forms an angle of 135 ° counterclockwise with respect to the horizontal direction (0 ° direction).
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver seat, front passenger seat, and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was reduced from any viewpoint.
Further, the liquid crystal display device was displayed in a state where the external light was brightened, and reflection of external light on the screen of the liquid crystal display device from the driver's seat, the passenger seat, and the rear seat of the vehicle was observed. As a result, no external light was reflected on the screen of the liquid crystal display device from any viewpoint.
Further, when the screen of the liquid crystal display device was directly observed, there was no degradation in visibility.

[Example 5]
In the same manner as in Example 3, an adhesive layer, a retardation film, and an adhesive layer were provided in this order on the surface of the liquid crystal display element on the side opposite to the liquid crystal cell of the viewing side polarizing plate. Then, the multilayer film manufactured in Example 4 (including the cholesteric resin layer, the hard coat layer, and the low refractive index layer in this order) is bonded to the surface of the exposed adhesive layer on the cholesteric resin layer side. It was. Thus, a liquid crystal display device including a light source, a light source side polarizing plate, a liquid crystal cell, a viewing side polarizing plate, a retardation film, a cholesteric resin layer, a hard coat layer, and a low refractive index layer was obtained.

In this liquid crystal display device, the transmission axis of the viewing side polarizing plate forms an angle of 135 ° counterclockwise with respect to the horizontal direction (0 ° direction), and the slow axis of the retardation film is parallel to the horizontal direction. It was arranged in the center of the instrument panel of the vehicle.
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver seat, front passenger seat, and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was reduced from any viewpoint.
Further, the liquid crystal display device was displayed in a state where the external light was brightened, and reflection of external light on the screen of the liquid crystal display device from the driver's seat, the passenger seat, and the rear seat of the vehicle was observed. As a result, no external light was reflected on the screen of the liquid crystal display device from any viewpoint.
Further, when the screen of the liquid crystal display device was directly observed, there was almost no decrease in visibility.

[Comparative Example 1]
A liquid crystal display device was manufactured in the same manner as in Example 1 except that the multilayer film manufactured in Manufacturing Example 3 was used instead of the multilayer film manufactured in Manufacturing Example 1. Placed in the department.
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver's seat, front passenger seat and rear seat of the vehicle was observed. As a result, it was confirmed that the reflection on the windshield of the screen of the liquid crystal display device was somewhat reduced from any viewpoint. However, when the screen of the liquid crystal display device was directly observed, a decrease in visibility was observed.

[Comparative Example 2]
When laminating the phase difference film, the slow axis of the phase difference film was laminated with the angle of 45 ° clockwise with respect to the transmission axis of the viewing side polarizing plate. The slow axis of the retardation film was made perpendicular to the horizontal direction when the liquid crystal display device was disposed on the multilayer film, and the multilayer film produced in Production Example 3 instead of the multilayer film produced in Production Example 2 A liquid crystal display device was manufactured in the same manner as in Example 3 except that a film was used, and the liquid crystal display device was arranged at the center of the instrument panel of the vehicle.
The liquid crystal display device was displayed in the absence of external light, and the reflection on the windshield from the driver's seat, front passenger seat and rear seat of the vehicle was observed. As a result, light from the screen of the liquid crystal display device is suppressed and dark, and when the screen of the liquid crystal display device is directly observed, the visibility is greatly reduced.

10, 20 and 30 Liquid crystal display device 100 Liquid crystal display element 110 Light source 120 Liquid crystal panel 121 Screen 130 Light source side polarizing plate 140 Liquid crystal cell 150 Viewing side polarizing plate 210 Cholesteric resin layer 300 Vehicle 310 User 320 Windshield 400 Light control element 420 Phase difference Layer 500 Light control element 530 Hard coat layer 540 Antireflection layer

Claims (5)

A light control element for being provided on the screen of an in-vehicle liquid crystal display element provided with a light source side polarizing plate and a viewing side polarizing plate,
The light control element includes a cholesteric resin layer having an average light transmittance of 60% to 75% in the non-polarized visible light region when non-polarized light is incident vertically, and the viewing-side polarization of the cholesteric resin layer. With an antireflection layer on the opposite side of the plate ,
The cholesteric resin layer is a layer film of a liquid crystal composition containing a liquid crystal compound is cured, the liquid crystalline compound, the refractive index anisotropy Δn is Ru 0.18 or more rod-like liquid crystal compound der, Light control element. A retardation layer is provided on the viewing side polarizing plate side of the cholesteric resin layer,
The light control element according to claim 1, wherein the retardation layer has an in-plane retardation of ¼ wavelength.   The light control element according to claim 2, wherein an angle formed by a transmission axis of the viewing side polarizing plate and a slow axis of the retardation layer is approximately 45 °.   The light control element according to claim 1, wherein a thickness of the cholesteric resin layer is 1.0 μm or more and 5 μm or less. An in-vehicle liquid crystal display device comprising a light source, a light source side polarizing plate, a liquid crystal cell, a viewing side polarizing plate, and the light control element according to any one of claims 1 to 4 .

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