JP6103108B1 - Light control film and method of manufacturing light control film - Google Patents

Abstract

Provided is a light control film capable of ensuring a sufficient amount of transmitted light by improving viewing angle characteristics by multi-domaining. In a light control film 1 in which a liquid crystal cell 4 is sandwiched between linearly polarizing plates 2 and 3, the liquid crystal cell 4 is formed by forming a transparent electrode 11 and an alignment layer 13 on a substrate 6 made of a transparent film material. It is sandwiched between the first laminate 5D, the second laminate 5U formed by forming the transparent electrode 16 and the alignment layer 17 on the base material 15 made of a transparent film material, and the first and second laminates 5D and 5U. The alignment layers 13 and 17 of the first and second stacked bodies 5D and 5U are photo-alignment layers, and a plurality of domains are formed by the alignment regulating force of the photo-alignment layer. In one laminate 5D, columnar spacers 12 are provided at the domain boundaries of the domains. [Selection] Figure 1

Description

  The present invention relates to a light control film that can be used for, for example, an electronic blind that is attached to a window to control the transmission of extraneous light.

  Conventionally, for example, various devices relating to a light control film that is attached to a window to control the transmission of external light have been proposed (Patent Documents 1 and 2). One such light control film uses liquid crystal. The light control film using the liquid crystal is prepared by sandwiching a liquid crystal material with a transparent film material having a transparent electrode and an alignment layer, and a liquid crystal cell between the linear polarizing plates. As a result, in this light control film, the orientation of the liquid crystal is changed by changing the electric field applied to the liquid crystal, thereby blocking or transmitting the extraneous light, and further changing the amount of transmitted light. To control.

  When such a light control film is used by being attached to a window or the like, when the incident light is not shielded, it is desired to transmit the external light with a sufficient transmittance.

  A liquid crystal display panel, which is one of image display panels, has a liquid crystal cell sandwiched between a pair of glass plates made of transparent electrodes and alignment films, and the liquid crystal cell is sandwiched between linear polarizing plates. Configured. The liquid crystal display panel displays a desired image by changing the electric field applied to the liquid crystal in units of pixels by patterning the transparent electrode.

  For such a liquid crystal display panel, various ideas for improving the viewing angle characteristics by multi-domaining have been proposed. In Patent Document 3, an alignment layer is formed by providing ribs such as linear protrusions and dotted protrusions. Thus, a multi-domain vertical alignment (MVA) method in the VA (Virtual Alignment) method has been proposed. Here, the VA method is a method of controlling the transmitted light by changing the alignment of the liquid crystal between vertical alignment and horizontal alignment. Generally, the liquid crystal layer is vertically aligned by vertically aligning the liquid crystal when no electric field is applied. A liquid crystal cell is formed by being sandwiched between layers, and the liquid crystal material is horizontally aligned by application of an electric field. Here, multi-domain means to provide a plurality of regions in which the behavior of liquid crystal molecules is different with respect to variable electric field. Generally, viewing angle characteristics are obtained by averaging (integrating) optical properties in a plurality of regions. Applied to improve.

  In addition, the liquid crystal display panel is configured such that a spacer is formed in a column shape using a photoresist, and the thickness of the liquid crystal layer is maintained by the spacer. In such a liquid crystal display panel, this type of spacer is disposed under a black matrix, which is a light-shielding portion between pixels, thereby effectively avoiding various effects caused by the spacer, and the thickness of the liquid crystal layer on a pixel basis. Is configured to hold.

  By the way, it is thought that the light control film can apply various liquid crystal drive systems utilized in the liquid crystal display panel by controlling the amount of transmitted light by controlling the polarization plane in the same manner as the liquid crystal display panel. Specifically, if a light control film is produced by applying the MVA method, it is considered that a light control film can be produced with improved viewing angle characteristics by multi-domaining.

  However, in the MVA image display panel, multi-domain is achieved by patterning the transparent electrode, forming ribs, etc., and the orientation of the liquid crystal material on the transparent electrode is locally deteriorated by patterning the transparent electrode. Or the ribs tend to reduce the transmittance during voltage application. Accordingly, when a light control film is produced simply by applying the MVA method related to a liquid crystal display panel, there is a problem that a sufficient amount of transmitted light cannot be secured.

JP 03-47392 A Japanese Patent Laid-Open No. 08-184273 Japanese Patent Laid-Open No. 11-242225

  The present invention has been made in view of such a situation, and an object of the present invention is to improve a viewing angle characteristic by multi-domaining and to secure a sufficient amount of transmitted light.

  In order to solve the above-mentioned problems, the present inventor has conducted intensive research and has made the multi-domain by the alignment regulating force of the photo-alignment layer, thereby improving the viewing angle characteristics and ensuring a sufficient amount of transmitted light. Furthermore, the idea of arranging a spacer at the domain boundary related to the multi-domain and further ensuring the amount of transmitted light has led to the completion of the present invention.

  Specifically, the present invention provides the following.

(1) In a light control film in which a liquid crystal cell is sandwiched between linear polarizing plates,
The liquid crystal cell is
A first laminate formed by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A second laminate formed by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A liquid crystal layer sandwiched between the first and second laminates,
The alignment layer of the first and / or second laminate is a photo-alignment layer;
A plurality of domains are formed by the alignment regulating force of the photo-alignment layer,
The light control film in which the said 1st laminated body was provided with the pillar-shaped spacer in the domain boundary of the said domain.

  According to (1), by providing columnar spacers at the domain boundaries, the regions where the transmittance is locally reduced are collected, and the area of the portion where the transmittance is reduced in the entire light control film is Can be reduced. As a result, the viewing angle characteristics can be improved by multi-domaining, and a sufficient amount of transmitted light can be secured.

(2) In (1),
The alignment layer is
A light control film in which an alignment regulating force is set so that the liquid crystal molecules are aligned such that a direction perpendicular to an extending direction of the domain boundary is a major axis direction of the liquid crystal molecules of the liquid crystal layer.

  According to (2), the part of the spacer where the transmittance decreases due to the disclination can be efficiently placed in the domain boundary where the transmittance decreases due to the disclination, thereby further improving the transmittance. can do.

(3) In (1) or (2),
A light control film in which the width of the domain is randomly changed in the direction in which the domains are continuous in a range of at least 100 mm arbitrarily selected in the repeating direction of the domains.

  According to (3), by changing the domain width at random, the outdoor scenery can be clearly seen through the light control film, and the viewing angle characteristics are improved by the multi-domain. In addition, a sufficient amount of transmitted light can be secured.

(4) In any one of (1), (2) and (3),
The spacer has a Vickers hardness value Xs of 16.9 or more and 40.2 or less,
The light control film whose Vickers hardness value Xf of the site | part of the said 2nd laminated body which the front-end | tip of the said spacer contacts is 11.8 or more and 35.9 or less.

  According to (4), the Vickers hardness value Xs of the spacer is 16.9 or more and 40.2 or less, and the Vickers hardness value Xf of the portion of the second laminated body with which the tip of the spacer contacts is 11.8 or more and 35. .9 or less reduces the situation in which the tip of the spacer penetrates into the opposite surface due to the pressing force during use, etc., reducing the occurrence of nonuniform cell gaps and local alignment failure In addition, leakage of the liquid crystal material can be effectively avoided. Further, it is possible to reduce the damage to the base material and to reduce the occurrence of cracks when the whole is bent. By these, the reliability regarding a spacer can be improved further compared with the past.

(5) a first laminate production step of producing a first laminate by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A second laminate production step of producing a second laminate by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A liquid crystal cell by sandwiching a liquid crystal layer between the first and second laminates,
The first laminate manufacturing step includes
A step of disposing a columnar spacer on the transparent electrode or on the alignment layer;
The first and / or second lamination step includes
A coating process in which a coating liquid is applied to the substrate to prepare a material layer of the photo-alignment layer;
Exposure for producing the alignment layer so that a plurality of domains are formed in the liquid crystal cell by repeatedly irradiating the material layer of the photo-alignment layer produced by the coating process with ultraviolet rays to set the alignment regulating force. A process,
The manufacturing method of the light control film which arrange | positions the said spacer in the domain boundary of the said domain.

  According to (5), by providing columnar spacers at the domain boundary, the regions where the transmittance is locally reduced are collected, and the area of the portion where the transmittance is reduced in the entire light control film is Can be reduced. As a result, the viewing angle characteristics can be improved by multi-domaining, and a sufficient amount of transmitted light can be secured.

  According to the present invention, a sufficient amount of transmitted light can be ensured by improving the viewing angle characteristics by multi-domaining.

It is sectional drawing which shows the light control film which concerns on 1st Embodiment of this invention. It is a figure where it uses for description of the orientation layer in the light control film of FIG. It is a figure where it uses for description of the other example of the orientation layer in the light control film of FIG. It is a figure where it uses for description of arrangement | positioning of the spacer in the light control film of FIG. It is a figure where it uses for description of the relationship between a spacer and orientation control force. FIG. 6 is a diagram for explaining the continuation of FIG. 5. It is a flowchart which shows the manufacturing process of the light control film of FIG. It is a figure where it uses for description of the detail of the manufacturing process of FIG. It is a figure where it uses for description of the exposure process in the manufacturing process of FIG. It is a figure where it uses for description of the light control film which concerns on 2nd Embodiment of this invention. It is a figure where it uses for description of the light control film which concerns on 3rd Embodiment of this invention.

[First Embodiment]
[Light control film]
FIG. 1 is a cross-sectional view showing a light control film according to the first embodiment of the present invention. This light control film 1 is used by being attached to an area for light control such as a window glass of a building, a showcase, an indoor transparent partition, etc. with an adhesive layer or the like, and the amount of transmitted light can be reduced by changing the applied voltage. Control.

  This light control film 1 is a film material that controls transmitted light using liquid crystal, and is configured by sandwiching a liquid crystal cell 4 for light control film between linear polarizing plates 2 and 3. Here, the linear polarizing plates 2 and 3 are formed by impregnating polyvinyl alcohol (PVA) with iodine or the like, and then stretched to form an optical functional layer that performs an optical function as a linear polarizing plate. TAC (triacetyl cellulose) The optical functional layer is sandwiched between base materials made of a transparent film material such as the above. The linearly polarizing plates 2 and 3 are arranged in the liquid crystal cell 4 by an adhesive layer made of an ultraviolet curable resin or the like in a crossed Nicol arrangement. The linear polarizing plates 2 and 3 are provided with retardation films 2A and 3A for optical compensation on the liquid crystal cell 4 side, respectively, but the retardation films 2A and 3A may be omitted as necessary.

  The liquid crystal cell 4 controls the polarization plane of transmitted light by an applied voltage to a transparent electrode described later. Thereby, the light control film 1 is comprised so that transmitted light can be controlled and various light control can be aimed at.

[Liquid crystal cell]
The liquid crystal cell 4 is configured by sandwiching a liquid crystal layer 8 between a lower laminate 5D and an upper laminate 5U which are first and second laminates in the form of a film. The lower laminate 5D is formed by producing a transparent electrode 11, a spacer 12, and an alignment layer 13 on a base 6 made of a transparent film material. The upper laminate 5U is formed by laminating a transparent electrode 16 and an alignment layer 17 on a base material 15 made of a transparent film material. The liquid crystal cell 4 is provided in the liquid crystal layer 8 by the MVA method that is a multi-domain method in the VA (Virtual Alignment) method by driving the transparent electrodes 11 and 16 provided in the upper stacked body 5U and the lower stacked body 5D. The orientation of the obtained liquid crystal material is controlled, thereby controlling the polarization plane of the transmitted light.

  Although various transparent film materials applicable to this kind of film material can be applied to the base materials 6 and 15, it is desirable to apply a film material having a small optical anisotropy. In this embodiment, although a polycarbonate film is applied to the base materials 6 and 15, a COP (cycloolefin polymer) film or the like may be applied.

  Various electrode materials applied to this kind of film material can be applied to the transparent electrodes 11 and 16, and in this embodiment, the transparent electrodes 11 and 16 are formed of a transparent electrode material made of ITO (Indium Tin Oxide).

  The spacer 12 is provided to define the thickness of the liquid crystal layer 8 and various resin materials can be widely applied. However, in this embodiment, the spacer 12 is made of a photoresist, and the transparent electrode 11 is made. A columnar shape such as a columnar shape is produced by applying a photoresist on 6 and exposing and developing. The spacer 12 may be provided on the upper laminate 5U, or may be provided on both the upper laminate 5U and the lower laminate 5D.

More specifically the spacer 12, the cylindrical shape due to 9μm or more cross-sectional circular diameter of less than 25 [mu] m, more preferably formed by a cylindrical shape by the above-sectional circular shape following 9μm diameter 12 [mu] m, 300 pieces 50 pieces / mm ² or more / although being disposed by the density of mm ² or less, it may be arranged by preferably 50 / mm ² or more 100 / mm ² or less of the density.

  The alignment layers 13 and 17 are formed of a photo-alignment layer. Here, as the material applicable to the photo-alignment layer, various materials to which the photo-alignment technique can be applied can be widely applied. However, in this embodiment, for example, a light dimerization type material is used. The light dimerization type material is described in “M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)”, “M. Schadt, H. Seiberle and A. Schuster: Nature, 381, 212 (1996).

  Various liquid crystal materials applicable to this type of light control film can be widely applied to the liquid crystal layer 8. Specifically, for the liquid crystal layer 8, for example, a liquid crystal compound described in JP-A No. 2003-366484 can be used. Moreover, as a marketed product, liquid crystal materials, such as Merck MLC2166, can be applied, for example. In the liquid crystal cell 4, a sealing material 19 is disposed so as to surround the liquid crystal layer 8, and the upper stacked body 5 </ b> U and the lower stacked body 5 </ b> D are integrally held by the sealing material 19, thereby preventing leakage of the liquid crystal material. .

[Multi-domain]
Here, the light control film 1 can be multi-domained by applying a photo-alignment layer to the alignment layers 13 and 17 and setting (patterning) the alignment regulating force of the photo-alignment layer. That is, the upper stacked body 5U and the lower stacked body 5D are formed in a rectangular shape in plan view, and the alignment layer 17 according to the upper stacked body 5U has a short side according to the rectangular shape as shown in FIG. First and second belt-like regions A and B extending along the direction are provided alternately and in close contact with each other in a direction perpendicular to the extending direction.

  The first and second regions A and B are regions related to the MVA type domains DA and DB, and are regions having different pretilt angles with respect to the liquid crystal material of the liquid crystal layer 8, thereby aligning them. It is produced so that the direction of the regulation force is different. More specifically, in this embodiment, the pretilt direction (indicated by arrows A and B) related to the pretilt angle is substantially vertical from the boundary between the first and second regions in the first and second regions. The direction is set to be the opposite direction. The direction of the pretilt related to the pretilt angle is set according to the direction of the light source used for exposure of the photo-alignment layer. Note that the first and second regions are produced so that the orientation regulating force is expressed in the same direction in the azimuth angle direction.

  Similarly, the alignment layer 13 according to the lower stacked body 5D is provided with the strip-like regions A and B alternately in order so as to correspond to the alignment layer 17 of the upper stacked body 5U. Thereby, in the liquid crystal cell 4, the first and second domains DA and DB by the band-like areas corresponding to the band-like areas A and B are provided alternately one by one, thereby being able to secure a sufficient viewing angle characteristic. The

  Here, in the example of FIG. 2A, on the premise that the directions of the pretilt angles related to the pretilt angles are different in the regions A and B, the reverse direction is a direction substantially perpendicular to the boundary between the first and second regions. Although the direction of the pretilt is set so as to be in the direction, the viewing angle characteristics can be sufficiently improved by setting the pretilt direction in the opposite directions in the first and second regions. As shown by (B), it may be an extension direction related to the band-like regions A and B, or may be inclined obliquely with respect to this extension direction.

  In addition, as shown in FIGS. 3A and 3B, the multi-domainization by the alignment regulating force of the photo-alignment layer is performed by patterning only one of the alignment layers 13 and 17, and the other alignment layer is The alignment regulating force may be set uniformly over the entire surface. In this case, the other alignment layer is a center that bisects the direction of the pretilt in the first and second regions A and B of the one alignment layer. It is desirable to set so that the direction is a pretilt direction. As described above, when only one of the alignment layers 13 and 17 is patterned and the alignment layer is uniformly set with respect to the other alignment layer, the upper stacked body 5U and the lower stacked body 5D The alignment at the time of lamination can be simplified.

  In the other alignment layer, a configuration in which a liquid crystal material in the vicinity is aligned with a tilt angle of 90 degrees when no electric field is applied can be applied. In addition, the configuration of such an alignment layer is, for example, a configuration in which the material layer of the photo-alignment layer is cured by non-polarized ultraviolet rays so as to function as a vertical alignment layer. It is possible to apply a configuration in which the material layer functions as a vertical alignment layer by keeping the layer just dried. Even if comprised in this way, the alignment at the time of lamination | stacking of the upper laminated body 5U and the lower laminated body 5D can be simplified.

  Note that the first and second regions A and B may be formed by a rectangular shape, a square shape, a rhombus shape, or the like instead of such a belt-like shape. In these cases, the first and second regions are formed in a checkered pattern. And second regions A and B are arranged.

  By making multi-domains by patterning the photo-alignment layer in this way, it is possible to effectively avoid a decrease in transmittance as in the case of multi-domains by patterning transparent electrodes and forming ribs. A sufficient amount of transmitted light can be ensured by improving the viewing angle characteristics by multi-domaining.

  Here, the widths WA and WB of the first and second regions A and B relating to the first and second domains DA and DB produced in this way are 30 μm or more and 3000 μm or less, more preferably 100 μm or more and 2000 μm. It is produced as follows. Here, when the widths WA and WB are large, the first and second domains are visually recognized and it is difficult to ensure the effect of improving the viewing angle characteristics. However, when the widths WA and WB are small, the domains The transmittance decreases due to the increase in the boundary. As a result, this embodiment is configured to effectively avoid a decrease in transmittance and to reliably improve viewing angle characteristics.

[Spacer arrangement]
By the way, when the multi-domain is formed by the alignment regulating force of the photo-alignment layer in this way, the transmittance is reduced by disclination at the domain boundary.

  Specifically, FIG. 4 is a schematic diagram illustrating a state in which the light control film formed by the liquid crystal cell 4 is observed with a microscope, and is a diagram illustrating a state in which incident light is transmitted by application of an electric field. In the light control film, a portion having a low luminance level is formed linearly at the domain boundary BD by the domains DA and DB. In the configuration of the alignment layers 13 and 17 shown in FIG. Is formed at each boundary, whereas in the configuration of the alignment layers 13 and 17 according to FIG. 3, one linear portion is formed at each boundary.

  Further, in the spacer 12, the liquid crystal molecules are disturbed around the spacer 12, so that the transmittance is lowered around the spacer 12.

  Therefore, in this embodiment, as shown in FIG. 4, by arranging the spacer 12 at the domain boundary BD, the portion where the transmittance is decreased due to the domain boundary BD and the portion where the transmittance is decreased due to the spacer 12 are overlapped. The area of the portion where the transmittance is reduced in the entire light control film 1 is reduced, so that a sufficient amount of transmitted light can be secured.

  Here, from the viewpoint of ensuring a sufficient amount of transmitted light, it is desirable to arrange all the spacers 12 arranged in the liquid crystal cell 4 at the domain boundary BD. However, when all of them are arranged at the domain boundary BD, the spacers 12 are regularly arranged in the continuous direction of the domains DA and DB, so that diffracted light is generated. As a result, the light is seen through the light control film. May reduce the resolution of the landscape. Thereby, in this embodiment, all or a part of the spacers 12 arranged on the light control film 1 is arranged on the domain boundary BD. The spacers 12 that are not arranged at the domain boundary BD are arranged at random. Further, even in the spacer 12 arranged at the domain boundary DB, the extending direction of the domain boundary BD is randomly arranged.

  Here, it is assumed that the diameter of the spacer 12 is W, the portion having a small luminance level appearing at the domain boundary BD is one and a straight portion, and the width of the domain is WD. In this case, the probability that the spacers 12 are arranged at random and the spacers 12 overlap even a part of the linear portion with a small luminance level appearing in the domain boundary DB is expressed by 2W / WD. Thereby, in this embodiment, from the viewpoint of ensuring a sufficient amount of transmitted light, 20% or more, preferably 35% or more, more preferably 50% or more of the spacers 12 arranged on the light control film 1 are more at the domain boundary BD. Specifically, it is arranged in a linear portion having a low luminance level generated at the domain boundary BD.

[Setting the alignment regulating force for the spacer]
Here, as shown in FIG. 5A, the alignment regulating force of the alignment layer 13 causes the liquid crystal molecules 8A to be aligned such that the direction of the alignment regulating force (indicated by an arrow) is the major axis direction. On the other hand, around the spacer 12, as shown in FIG. 5B, the liquid crystal molecules 8A are aligned perpendicularly to the peripheral side surface of the spacer 12. As a result, as shown in FIG. 5C, the transmittance decreases due to disclination around the spacer 12 in a direction crossing the direction of the alignment regulating force of the alignment layer. Region AR occurs.

  As a result, as described above with reference to FIGS. 2B and 3B, the first and second regions A and B in the extending direction of the boundary between the first and second regions A and B related to the domain boundary BD. When the pretilt direction in the direction intersecting with B is set, as shown in FIG. 6A, the area AR in which the transmittance is reduced by the disclination by the spacer 12 is efficiently arranged on the domain boundary BD. Can not be. However, the direction perpendicular to the extending direction of the boundary between the first and second regions A and B relating to the domain boundary BD described above with reference to FIGS. 2A and 3A is the pretilt direction (direction of the alignment regulating force). As shown in FIG. 6B, the area AR in which the transmittance is reduced by the disclination by the spacer 12 can be efficiently arranged on the domain boundary BD. As a result, the direction perpendicular to the direction of the orientation regulating force can be set to be the extending direction of the domain boundary BD, and the transmittance can be further improved.

  Note that, as shown in FIG. 6C, for example, when the direction of the orientation regulating force is set to be orthogonal with the domain boundary BD interposed therebetween, it is orthogonal to the orthogonal orientation regulating force. The direction can be the direction of the area AR in which the transmittance is reduced, and this can be applied to the case of multi-domaining by, for example, four domains.

[Detailed configuration of spacer]
Here, in this embodiment, as described above, the spacer 12 is formed in a cylindrical shape or a truncated cone shape using a photoresist. Thus, the spacer 12 is produced, and in this embodiment, the Vickers hardness value Xs of the spacer 12 is 16.9 or more and 40.2 or less, and the portion of the second laminated body 5U where the tip of the spacer 12 abuts. The Vickers hardness value Xf is set to be 11.8 or more and 35.9 or less, thereby further improving the reliability of the spacer as compared with the conventional case. In addition, the value of Vickers hardness is a measured value under the conditions described in the following examples.

  That is, when the Vickers hardness value Xf of the portion of the second laminate 5U with which the tip of the spacer 12 abuts is less than 11.8, the tip of the spacer 12 penetrates into the opposite surface due to the pressing force during use, and as a result In addition, the cell gap becomes non-uniform or local alignment failure occurs. Further, in this case, the base material 21A is scratched by contact or the like at the time of assembling the spacer 12, or a crack is generated when the whole is bent.

  In addition, when the Vickers hardness value Xs of the spacer 12 is less than 16.9, the spacer 12 is crushed by the external pressure, the cell gap is reduced, and a desired cell gap cannot be obtained. Even if the Vickers hardness value Xs of the spacer 12 exceeds 40.2, or the Vickers hardness value Xf of the portion of the second laminated body 5U with which the tip of the spacer 12 abuts exceeds 35.9, the cell The gap may be reduced, and scratches and cracks may occur.

  However, the Vickers hardness value Xs of the spacer 12 is 16.9 or more and 40.2 or less, and the Vickers hardness value Xf of the portion of the second laminate 5U with which the tip of the spacer 12 abuts is 11.8 or more and 35.9 or less. If it is set to be such that these problems can be solved at once, the reliability of the spacer can be further improved as compared with the conventional case.

〔Test results〕
Tables 1 and 2 are charts showing test results used for confirming the configuration related to the spacer. The examples and comparative examples in Tables 1 and 2 are configured identically except that the configurations related to the spacer and the alignment layer with which the spacer abuts are different. More specifically, in the light control films of these examples and comparative examples, the spacer 12 is provided only on the lower laminate 5D, and the Vickers hardness value Xs of the spacer 12 is changed depending on the heat treatment conditions related to the spacer 12. I let you. Further, the Vickers hardness value Xf of the portion of the second stacked body 5U with which the tip of the spacer 12 abuts was changed according to the conditions for producing the alignment layer 23A.

  In other words, the spacer 12 is coated with the coating liquid related to the spacer 12 and then dried, and then a portion where the spacer 12 is produced is selectively exposed by mask exposure using an exposure apparatus. Note that this is a case of a positive type photoresist. On the contrary, in the case of a negative type photoresist, a part other than the part for producing the spacer 12 is selectively exposed. Thereafter, the spacer 12 is selectively removed at the unexposed portion or the exposed portion by development processing, and processing such as rinsing is performed, and processing such as drying is performed as necessary.

  In this exposure process, exposure may be performed in a so-called half-cure state by heating in advance or in a heated environment. In the development process, after rinsing or the like is performed, the heat treatment is performed. May accelerate the reaction. The hardness Xs of the spacer 12 can be set by selecting a photoresist material related to the spacer 12, setting the heating temperature and time in the exposure process and the development process, and setting the exposure light amount and the exposure time.

  In this embodiment, the Vickers hardness value Xs of the spacer 12 is 14.8, 16.9, 22.2, 40.2, and 51.4 depending on the setting of the heating temperature and time in the exposure process and the development process, respectively. A lower laminate 5D was produced. The hardness is a measurement value obtained by setting the production conditions of the spacers 12 to produce the lower laminate 5D, and once producing the light control film 10 using the lower laminate 5D, and then disassembling and measuring. . In addition, this measurement is a measurement result based on an average value of 10 points which are obtained by measuring 12 points with each light control film and excluding the maximum value and the minimum value.

The spacer 12 was produced in a cylindrical shape having a diameter of 9 μm and a height of 6 μm. Further, they were regularly arranged at a pitch of 110 μm in two directions orthogonal to the in-plane direction of the base material 21B. Therefore, the ratio (occupation ratio) occupied by the spacers 12 on the base material 21B is 0.5% (= ((9/2) ² × 3) / (110) ² ).

  Increasing the occupation ratio reduces the stress applied to each spacer, thereby reducing the phenomenon that the spacer 12 is crushed or the tip penetrates. However, increasing the occupation ratio deteriorates the transmittance. Or the shading rate deteriorates. However, when the occupation ratio is small, optical characteristics such as transmittance and light blocking ratio can be secured, but it is unavoidable that the spacer 12 is crushed or the tip penetrates. Thus, the occupation ratio is desirably 0.5% or more and 10% or less.

  On the other hand, the alignment layer 23A of the upper laminate 12 on which the spacer abuts is manufactured by applying a coating liquid, drying, and heat-curing. Vickers hardness value Xf was set by setting temperature, heating time, and the like. Thereby, in the Example and the comparative example, the upper side laminated body 12 whose Vickers hardness value Xf is 10.2, 11.8, 24.8, 35.9, 38.5 was manufactured (Table 4). For the hardness Xf, the upper laminate 12 having different hardness is produced for the orientation layer 23A of the upper laminate 12 which is a surface with which the spacer contacts by setting the creation conditions of the orientation layer 23A. After the light control film 10 is once manufactured by the above, it is a measured value obtained by disassembling and measuring. This is a measurement result of an average value of 10 points that are measured at 12 points and remain except for the maximum and minimum values.

  The Vickers hardness values Xs and Xf were measured using a PICODETOR HM500 manufactured by Helmut Fischer. The measurement was performed under the measurement conditions of a maximum load of 100 mN with an indentation speed of 300 mN / 20 sec, a release speed of 300 mN / 20 sec, and a creep time of 5 seconds.

  In each example and comparative example of Table 1 and Display 2, a light control film was produced and tested using the upper laminate 5U and the lower laminate 5D thus produced. In the tests of Tables 1 and 2, with the light control film placed on a smooth surface having high hardness by a surface plate, a load corresponding to 0.8 MPa was applied, and then the cell gap was measured to reduce the cell gap. Judged. The weighting time is 24 hours. After weighting in this manner, the upper laminate and the lower laminate are peeled off, the spacer is observed with a microscope, the spacer is crushed, the cell gap is reduced, and the part where the spacer contacts is Observation of the tip of the spacer was observed with a microscope.

  Here, for observation with this microscope, a front view, a perspective view, and a cross-section are observed using a method such as SEM, and the deformation of the spacer is visually confirmed. When the deformation of the spacer is confirmed, according to the situation, “ The presence or absence of “cell gap reduction, spacer crushing” was judged as “Good”. Therefore, in Tables 1 and 2, “◯” indicates a case where no abnormality relating to the corresponding item is observed, and “X” indicates a case where abnormality relating to the corresponding item is observed.

  Similarly, when the part where the spacer abuts is perspective using a technique such as SEM, if a depression (recess) is confirmed, “film penetration” is determined as “x”, and if a recess is not recognized, “film” “Intrusion” was determined as “◯”.

  Further, in a state where the laminates 5U and 13 were laminated and a load corresponding to 0.1 MPa was applied, the relative positions of the laminates 5U and 13 were displaced by 0.1 cm / sec, and the occurrence of scratches was confirmed visually. Here, when scratches are confirmed in more than half of the multiple samples, “scratch (film)” is indicated by “x”, and conversely, scratches are not confirmed in more than half of the multiple samples. In this case, “scratches” are indicated by “◯”.

  Further, in the state of the light control film, it was wound around a cylindrical mandrel having a diameter of 2 mm in accordance with the bending test of JIS K5600-5-1 to confirm the occurrence of cracks. In this test, when cracks are confirmed in the substrate in more than half of the multiple samples, “crack (film)” is indicated by “x”, and conversely, in more than half of the multiple samples, the substrate In the case where no crack is confirmed, “crack” is indicated by “◯”.

  In the measurement results of Tables 1 and 2, when the Vickers hardness value Xs of the spacer 12 is less than 16.9 (Comparative Examples 5 and 7), a decrease in the cell gap is observed. Intrusion, scratches, and cracks at the spacer tips were observed. Further, when the Vickers hardness value Xf of the portion of the second laminate 5U with which the tip of the spacer 12 abuts is less than 11.8 (Comparative Example 1 and Comparative Example 3), scratches and cracks are observed, and Comparative Example In 3, the penetration of the spacer tip into the film was observed.

  When the Vickers hardness value Xs of the spacer 12 exceeds 40.2 (Comparative Example 6 and Comparative Example 8), in Comparative Example 6, a decrease in the cell gap and penetration of the spacer tip into the film are observed. Scratches were observed. Further, when the Vickers hardness value Xf of the portion of the second laminated body 5U with which the tip of the spacer 12 abuts exceeds 35.9 (Comparative Example 2 and Comparative Example 4), a decrease in cell gap and scratches are observed, and further comparison is made. In Example 4, cracks were observed.

  However, in Examples 1-13, in these phenomena, it was not observed and it was confirmed that the reliability regarding the spacer can be sufficiently secured.

〔Manufacturing process〕
FIG. 7 is a flowchart for explaining the manufacturing process of the light control film. In the manufacturing process of the light control film, the upper laminate 5U and the lower laminate 5D are produced in the upper laminate production step SP2 and the lower laminate production step SP3, respectively. Further, in the stacking step SP4, the upper stacked body 5U and the lower stacked body 5D are stacked with the liquid crystal layer 8 interposed therebetween, and then integrated by the sealing material 19 to manufacture a liquid crystal cell. In the manufacturing process of the light control film, the liquid crystal cell thus prepared is laminated and integrated with the linear polarizing plate to prepare a light control film.

  FIG. 8 is a flowchart showing manufacturing steps of the upper laminate 5U and the lower laminate 5D. In this manufacturing process, in the electrode manufacturing process SP12, a photolithography technique is applied to create the transparent electrodes 11 and 16 on the transparent substrates 6 and 15, respectively. Further, in the lower laminate 5D, in the spacer production step SP13, a photoresist film is produced on the transparent substrate 6 on which the transparent electrode 11 is produced, and then exposed and developed, whereby the spacer 12 is produced. To do. Subsequently, in the manufacturing process, the alignment layers 13 and 17 are formed on the base materials 6 and 15 in the alignment layer manufacturing process SP4.

  Here, in the alignment layer preparation step SP4, in the coating step SP4-1, after coating the coating liquid related to the photo-alignment layer on the substrates 6 and 15, respectively, in the subsequent drying step SP4-2, The solvent of this coating solution is scattered to dry the coating layer. Thereby, this manufacturing process produces the alignment layer 13 which concerns on a vertical alignment layer on the base-material 6 side.

  Further, in this manufacturing process, in the subsequent first exposure process SP4-3, the material layer of the alignment layer formed on the substrate 15 side is irradiated with ultraviolet rays, and the alignment regulating force related to the first or second region is entirely applied. In the subsequent second exposure step SP4-4, the alignment regulating force is reset for the second or first region by irradiation of ultraviolet rays using a mask, and thereby the alignment layer 17 is produced.

  Here, as shown in FIG. 9A, in this embodiment, the repeating direction of the first and second regions A and B (the left-right direction on the paper surface and the direction orthogonal to the boundary between the regions A and B). ) Is arranged on one side, and linearly polarized ultraviolet rays LA are obliquely incident on the base material 15 from the light source at a predetermined incident angle θA to execute the first exposure process. The orientation regulating force related to the region A or B is expressed in

  Subsequently, as shown in FIG. 9B, a mask 21 that selectively shields the region A or B is disposed, and the non-polarized light is incident on the incident angle θB from the light source disposed on the opposite side to the first exposure. The ultraviolet ray LB is obliquely incident and the second exposure process is executed, thereby resetting the alignment regulating force related to the region A or B. When resetting the orientation regulating force in this way, the second time for the irradiation of the ultraviolet ray LA related to the first setting of the orientation regulating force (this is the first ultraviolet ray irradiation according to FIG. 3A). It is desirable to set the irradiation light amount of the ultraviolet ray LB in the exposure processing of 2 times or more.

  In addition, although it is desirable that the light source according to the incident angles θA and θB has an angular interval of 180 degrees in the azimuth angle direction, if the angular interval related to the azimuth angle is within a range of 180 degrees ± 1 degree, it is practical. A sufficient pretilt angle can be set. Further, instead of the arrangement of the light source in the direction orthogonal to the boundary between the regions A and B, the light source may be arranged in a direction inclined obliquely from the orthogonal direction to perform the exposure processing. Further, from the viewpoint of efficiently producing the photo-alignment layer with a small amount of light, the incident angles θA and θB are desirably 45 degrees, but may be 40 degrees or more and 50 degrees or less.

  When exposure processing is performed using the mask 21 in this way, in this manufacturing process, the mask 21 is positioned and exposure processing is performed so that the spacer 12 overlaps the domain boundary, thereby ensuring sufficient transmittance.

  According to this embodiment, by providing a spacer at the domain boundary, it is possible to secure a sufficient amount of transmitted light so as to improve the viewing angle characteristics by multi-domaining.

〔Example〕
A COP film material having a thickness of 100 μm formed by forming hard coat layers on both sides was applied to the base materials 6 and 15, and a light control film was produced according to the configuration of the above-described embodiment. The first exposure process is performed by irradiating linearly polarized UV light with a light amount of 10 mJ / cm ^{2, and} the second exposure process is performed with mask exposure using linearly polarized UV light with a light intensity of 30 mJ / cm ^2. Thus, the alignment layer 17 according to the upper laminate 5U was produced. The alignment layer 13 according to the lower laminate 5D was formed of a vertical alignment layer by simply drying the photo-alignment layer material layer without performing an exposure process. In this example, the transmittance was 32.4%.

[Comparative Example]
In this comparative example, a light control film was produced in the same manner as in Example 1 except that the spacers were arranged at a constant pitch while ignoring the domain boundary. In this comparative example, the transmittance was 31.4%.

[Second Embodiment]
FIG. 10 is a diagram for explaining the light control film according to the second embodiment of the present invention in comparison with FIG. 4. In the light control film according to this embodiment, as in the first embodiment, the first and second domains DA and DB are sequentially and repeatedly repeated by the alignment regulating force of the photo-alignment layer, This improves viewing angle characteristics.

  In this light control film, the adjacent first and second domains DA and DB are sequentially formed as a domain pair DP. In each domain pair DP, the width WA of the first and second domains DA and DB and WB is set to be equal to each other, so that the first and second domains DA and DB in each domain pair mutually complement the viewing angle characteristics so that the viewing angle characteristics can be sufficiently improved as a whole. .

  In this way, the light control film 1 is formed such that the widths W1, W2, and W3 due to the domain pair DP change randomly in the domain DA and DB continuously. Thereby, in the light control film 1, the area | region width WA and WB of the 1st and 2nd area | regions A and B is formed so that it may change at random corresponding to the width W1, W2, and W3 of this domain pair DP. . Thereby, in the light control film 1, the regularity of the domains DA and DB related to the multi-domain is relaxed. Thereby, in the light control film 1, the diffracted light by the regularity of this domain DA and DB is reduced, and the fall of the resolution is avoided effectively by this diffracted light. Thereby, in this embodiment, an outdoor scenery etc. can be clearly seen through a light control film, without being amazed or stunned.

  Here, when the widths W1, W2, and W3 of the domain pair DP are changed randomly and continuously in the domains DA and DB, the widths WA and WB of the first and second regions A and B vary. Here, the variation of the widths WA and WB is set so that the standard deviation (σ) is 30 μm or more and 80 μm or less, more preferably 40 μm or more and 70 μm or less so that the regularity can be sufficiently relaxed by this variation.

  In addition, in this way, the first and second regions A and B (with substantially the same width) are set so that the regularity is not secured locally by the continuation of the domains DA and DB with the same width. The absolute value of the difference between the widths WA and WB is 20 μm or less).

  Here, in the relaxation of such regularity, it is possible to ensure that the outdoor scenery and the like can be clearly seen by ensuring the area within a certain range. As a result of various studies, it has been found that this certain range is a range of 100 mm or more in the domain continuous direction. As a result, in this embodiment, the domain pair D is produced so that the same pattern repeats at a repetition pitch of 100 mm or more, whereby patterning using the same mask related to random arrangement is used repeatedly or according to random arrangement The alignment layer can be formed by patterning using a large-area mask with repeated portions.

  Thus, in the light control film 1, in the range of at least 100 mm arbitrarily selected in the repeating direction of the first and second regions A and B, the first and second region widths are the same as those of the first and second regions. It is set to change randomly in a continuous direction, thereby sufficiently reducing the diffracted light due to the regularity of the domains DA and DB, so that the outdoor scenery etc. can be clearly seen without being fooled or stunned. it can.

[Spacer arrangement]
In this embodiment, the spacers 12 are arranged on the domain boundaries formed by sufficiently relaxing the regularity of the domains DA and DB. Here, in this embodiment, since the regularity of the domain boundary is sufficiently relaxed in the first place, even if a much larger number of spacers 12 are arranged at the domain boundary as compared with the first embodiment, Even if all the spacers 12 are arranged at the domain boundary, the regularity related to the arrangement of the spacers 12 can be sufficiently relaxed. This ensures a sufficient amount of transmitted light, prevents diffracted light due to this regularity, and allows the outdoor scenery and the like to be clearly seen without being disturbed or stunned.

  According to this embodiment, in a range of at least 100 mm arbitrarily selected in the domain repeat direction, the width of the domain is randomly changed in the domain continuous direction so as to ensure a sufficient amount of transmitted light. The outdoor scenery can be seen clearly.

[Third Embodiment]
FIGS. 11 (A) and (B) serve to explain the light control film according to the second embodiment of the present invention by comparing with FIGS. 2 (A) and 2 (B) and FIGS. 3 (A) and 3 (B). FIG. In this embodiment, a photo-alignment layer is applied to the alignment layer 17 of the upper stacked body 5U and the alignment layer 13 of the lower stacked body 5D, and the first and second belt-shaped regions whose directions related to the pretilt angle are opposite to each other. AA and BA, BB and AB are formed, and the first and second belt-like regions AA and BA, BB and AB are arranged so as to be orthogonal to each other. Thus, in this embodiment, the multi-domain is formed by four domains. Thereby, in this embodiment, viewing angle characteristics are further improved.

  In this embodiment, spacers 12 are arranged at the domain boundaries related to these four domains. In this case, each domain may be formed with a constant width, and both the alignment layer 13 of the lower stacked body 5D and the alignment layer 17 of the upper stacked body 5U are both the same as described above for the second embodiment. Alternatively, one or the other may be set such that the domain width changes randomly in the domain continuous direction within a range of at least 100 mm arbitrarily selected in the domain repeat direction.

  Even in the case of multi-domaining by four domains as in this embodiment, the same effect as in the first embodiment or the second embodiment can be obtained.

[Other Embodiments]
The specific configuration suitable for the implementation of the present invention has been described in detail above, but the present invention can be variously combined and further modified in various ways within the scope of the present invention. Can do.

  That is, in the above-described embodiment, the case where the photo-alignment layer is produced by the close arrangement of the first and second regions by the selective exposure process using the mask after the entire surface is exposed is processed. Not limited to this, a portion of the first or second region is selectively exposed using a mask, and then an unexposed portion of the second or first region is exposed by ultraviolet irradiation. Thus, a photo-alignment layer having a close arrangement of the first and second regions may be produced. In this case, the amount of light used for the first exposure process and the second exposure process is set to be approximately equal, and more specifically, the amount of light related to the second exposure process is 1.25 times or less of the amount of light related to the first exposure process. When the ratio is 0.75 times or more, a photo-alignment layer can be produced by closely arranging the first and second regions. Alternatively, a photo-alignment layer having a close arrangement of the first and second regions may be produced by repeating an exposure process using a mask.

  Further, in the above-described embodiment, the case where the spacer is manufactured in a columnar shape has been described. However, the present invention is not limited to this, and can be widely applied to the case where the spacer is manufactured in a columnar shape with an elliptical cross section.

DESCRIPTION OF SYMBOLS 1 Light control film 2, 3 Linearly polarizing plate 2A, 3A Phase difference film 4 Liquid crystal cell 5D Lower laminated body (1st laminated body)
5U upper laminate (second laminate)
6, 15 Base material 8 Liquid crystal layer 8A Liquid crystal molecule 11, 16 Transparent electrode 12 Spacer 13, 17 Alignment layer 19 Sealing material 21 Mask

Claims (4)

In the light control film formed by sandwiching the liquid crystal cell with a linear polarizing plate,
The liquid crystal cell is
A first laminate formed by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A second laminate formed by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A liquid crystal layer sandwiched between the first and second laminates,
The alignment layer of the first and / or second laminate is a photo-alignment layer;
A plurality of domains are formed by the alignment regulating force of the photo-alignment layer,
Wherein the first laminate, the domain boundaries of the domain, the spacer pillars shape provided et al is,
A light control film in which the width of the domain is randomly changed in the direction in which the domains are continuous in a range of at least 100 mm arbitrarily selected in the repeating direction of the domains . The alignment layer is
The light control film according to claim 1, wherein the alignment regulating force is set so that the liquid crystal molecules are aligned such that a direction perpendicular to an extending direction of the domain boundary is a major axis direction of the liquid crystal molecules of the liquid crystal layer. . The spacer has a Vickers hardness value Xs of 16.9 or more and 40.2 or less,
3. The light control film according to claim 1, wherein a Vickers hardness value Xf of a portion of the second laminated body with which the tip of the spacer abuts is 11.8 or more and 35.9 or less. A first laminate production step of producing a first laminate by producing a transparent electrode and an orientation layer on a substrate made of a transparent film material;
A second laminate production step of producing a second laminate by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A liquid crystal cell by sandwiching a liquid crystal layer between the first and second laminates,
The first laminate manufacturing step includes
A step of disposing a columnar spacer on the transparent electrode or on the alignment layer;
The first and / or second lamination step includes
A coating process in which a coating liquid is applied to the substrate to prepare a material layer of the photo-alignment layer;
Exposure for producing the alignment layer so that a plurality of domains are formed in the liquid crystal cell by repeatedly irradiating the material layer of the photo-alignment layer produced by the coating process with ultraviolet rays to set the alignment regulating force. A process,
Placing the spacer at the domain boundary of the domain ;
The said domain is a manufacturing method of the light control film formed so that the width | variety of the said domain may change at random in the continuous direction of the said domain in the range of the at least 100 mm arbitrarily selected in the repeating direction of the said domain .

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