JP7587769B2 - Light control device - Google Patents

Description

The present invention relates to a light control device that can adjust the light transmittance, and in particular to a light control device that includes a liquid crystal drive type light control cell that can be attached to a curved surface.

Dimmers capable of changing the light transmittance have been known for some time. For example, a suspended particle device (SPD) is known that uses suspended particles whose alignment state changes depending on whether an electric field is applied. Also known are electrochromic (EC) type dimming devices, dimming devices that use polymer dispersed liquid crystal (PDLC), gasochromic type dimming devices, thermochromic type dimming devices, and photochromic type dimming devices.

For example, Patent Document 1 discloses a laminate film used in SPDs. The SPD described in Patent Document 1 uses a suspension in which suspended particles are mixed into a liquid medium, and when the power is off and no electric field is applied, the particles are randomly arranged to block the transmission of light. On the other hand, when the power is on and an electric field is applied, the particles are aligned, and most of the light that enters the SPD (cell) passes through the SPD. Therefore, users can change the light transmittance of the SPD by controlling the electric field applied to the suspension.

JP 2011-189751 A

In addition to the SPD mentioned above, a method of adjusting the light transmittance using a dimming cell can be considered that uses liquid crystal and a polarizing plate. A dimming cell that uses liquid crystal and a polarizing plate can be simply constructed and can ensure very high light blocking performance.

For example, when applying a light control cell to a vehicle window, in order to properly block sunlight when shading, it is required to suppress the transmittance of light in the visible wavelength range (i.e. visible light) to less than 1%, and in some cases to 0.5% or less. However, the light control cell using the above-mentioned SPD has a visible light transmittance of about 1% to 5% when shading, so it is not necessarily suitable for use in vehicles and the like in terms of light blocking performance. On the other hand, a light control cell using a polarizing plate can suppress the visible light transmittance to 0.1% or less when shading, and has sufficient light blocking performance for practical use in vehicles and the like.

In addition, when comparing a dimming cell using an SPD with a dimming cell using a polarizing plate, the dimming cell using a polarizing plate is superior in various aspects such as design, cost, driving voltage, and driving speed. For example, the color of a dimming cell using an SPD when blocking light is "blue," whereas the color of a dimming cell using a polarizing plate when blocking light is "black." In general, black is easier to harmonize with other colors than blue, and from the standpoint of design, black is easier to select the color of other items to be placed around the dimming cell. Furthermore, dimming cells using SPDs have higher manufacturing costs, higher driving voltages, and slower driving speeds than dimming cells using polarizing plates.

As such, since light-control cells using polarizing plates have many advantages in terms of performance compared to light-control cells using SPDs, "light-control cells using polarizing plates" are extremely useful.

On the other hand, there is a growing need for light-control cells that can be applied to curved surfaces as well as flat surfaces, in order to enable the application of light-control cells to a variety of uses. Therefore, there is a demand for technology that allows "light-control cells using polarizing plates" that can ensure the desired light-transmitting and light-blocking properties to be appropriately applied to curved surfaces.

Generally, glass substrates are widely used as substrates for holding electrodes to control the orientation of liquid crystal components, but glass substrates are very hard and inflexible. Therefore, dimming cells equipped with glass substrates have a fixed shape, and the shape of the dimming cell cannot be changed after the dimming cell is manufactured. Therefore, dimming cells using glass substrates can be effectively applied to flat surfaces, but cannot necessarily be appropriately applied to curved surfaces that may have various curvatures. On the other hand, by using a flexible resin substrate instead of a glass substrate, the shape of the dimming cell can be changed even after the dimming cell is manufactured, and it is also possible to bend the dimming cell according to the curved surface to which it is to be attached.

However, it is not necessarily easy to properly attach a light-control cell, which is made up of multiple components with various rigidities and elasticities, to a curved surface, and wrinkles and other distortions may occur in sheet-shaped light-control cells when they are attached. Such wrinkles and other distortions not only affect the optical properties of the light-control cell and impair its original light-transmitting and light-blocking performance, but also undesirably impair the product design.

Although a dimming cell using an SPD as disclosed in the above-mentioned Patent Document 1 can be formed into a curved shape, it is not a type that is bonded to the object to be attached, so it must be made in a predetermined shape, making it difficult to flexibly accommodate various surface shapes.

The present invention was made in consideration of the above circumstances, and aims to provide a dimming device that can properly attach a dimming cell to a curved surface and has high light transmission and blocking performance.

One aspect of the present invention is a light control device comprising: a light-transmitting plate having a curved surface and containing an ultraviolet-blocking component that blocks the transmission of ultraviolet rays; a light control cell; and an optically transparent adhesive film disposed between the curved surface of the light-transmitting plate and the light control cell, and adhering one side of the light control cell to the curved surface of the light-transmitting plate. The light control cell comprises a first polarizing plate, a second polarizing plate disposed at a position farther away from the light-transmitting plate than the first polarizing plate, a hard coat layer disposed at a position farther away from the light-transmitting plate than the second polarizing plate, and a hard coat layer disposed between the first polarizing plate and the second polarizing plate, and the first polarizing plate. The light control device includes a first resin substrate arranged on the side of the first polarizer and a second resin substrate arranged on the side of the second polarizer, a first electrode layer arranged on the first resin substrate side and a second electrode layer arranged on the second resin substrate side, which are provided between the first resin substrate and the second resin substrate, a first alignment film arranged on the first electrode layer side and a second alignment film arranged on the second electrode layer side, which are provided between the first electrode layer and the second electrode layer, a sealant arranged between the first alignment film and the second alignment film, which divides a liquid crystal space between the first alignment film and the second alignment film, and a liquid crystal layer provided in the liquid crystal space.

The curved surface of the light-transmitting plate may be a three-dimensional curved surface.

The optically transparent adhesive film has a thickness in the direction in which the optically transparent adhesive film and the light control cell are laminated of 50 μm or more and 500 μm or less, preferably 200 μm or more and 300 μm or less, and the storage modulus in a room temperature environment (e.g., 1 to 30° C. (particularly 15 to 25° C.)) is more preferably 1×10 ⁷ Pa or more and 1×10 ⁸ Pa or less. The loss tangent (tan δ) of the optically transparent adhesive film is preferably 0.5 to 1.5, more preferably 0.7 to 1.2. The "loss tangent" here is expressed as the ratio of the storage shear modulus (G') and the loss shear modulus (G'') (i.e., "G''/G'").

At least one of the first resin substrate and the second resin substrate may contain polycarbonate or cycloolefin polymer.

The length of the sealing material in a direction perpendicular to the direction in which the first alignment film, the sealing material, and the second alignment film are stacked may be 1 mm or more and 5 mm or less.

It is preferable that the liquid crystal layer is at the same pressure as atmospheric pressure, but it is even more preferable that the liquid crystal layer be at a negative pressure relative to atmospheric pressure.

The light control device may further include a phase difference compensation film provided at least either between the first polarizer and the first electrode layer or between the second polarizer and the second electrode layer.

The liquid crystal layer may be a VA type, TN type, IPS type, or FFS type liquid crystal layer.

The optical axis of the first resin substrate may be perpendicular to the optical axis of the second resin substrate, the optical axis of the first resin substrate may be parallel to the absorption axis of the first polarizer, and the optical axis of the second resin substrate may be parallel to the absorption axis of the second polarizer.

The optical axis of the first resin substrate and the optical axis of the second resin substrate may be parallel, the optical axis of the first resin substrate may be perpendicular to the absorption axis of the first polarizer, and the optical axis of the second resin substrate may be parallel to the absorption axis of the second polarizer.

The light control device may further include a retardation compensation film provided between the first resin substrate and the first polarizing plate, the absorption axis of the first polarizing plate may be perpendicular to the absorption axis of the second polarizing plate, the retardation compensation film may function as an A plate, and the slow axis direction of the retardation compensation film may be parallel to the optical axis of the first resin substrate, the optical axis of the second resin substrate, and the absorption axis of the second polarizing plate. The light control device may further include a retardation compensation film provided between the second resin substrate and the second polarizing plate, the absorption axis of the first polarizing plate may be perpendicular to the absorption axis of the second polarizing plate, the retardation compensation film may function as an A plate, and the slow axis direction of the retardation compensation film may be parallel to the optical axis of the first resin substrate, the optical axis of the second resin substrate, and the absorption axis of the first polarizing plate.

The light control device may further include a plurality of spacers disposed at least in the liquid crystal space and supporting the first alignment film and the second alignment film, and when the Vickers hardness value of each of the plurality of spacers is represented by Xs and the Vickers hardness value of the portion of the first alignment film where the tip of each of the plurality of spacers abuts is represented by Xf, 16.9≦Xs≦40.2 is satisfied, and 11.8≦Xf≦35.9 may also be satisfied.

Another aspect of the present invention relates to a light control device that includes a light-transmitting plate having a curved surface, a light control cell, and an optically transparent adhesive film that is disposed between the curved surface of the light-transmitting plate and the light control cell and adheres one side of the light control cell to the curved surface of the light-transmitting plate, the light control cell having a liquid crystal layer that includes a dichroic dye.

Another aspect of the present invention relates to a dimming device that includes a light-transmitting plate having a curved surface, a dimming cell, and an optically transparent adhesive film that is disposed between the curved surface of the light-transmitting plate and the dimming cell and adheres one side of the dimming cell to the curved surface of the light-transmitting plate, in which the dimming cell includes a first laminate including a first substrate, a first transparent electrode and a first alignment film provided on the first substrate, a second laminate including a second substrate, and a second alignment film provided on the second substrate, and a liquid crystal layer provided between the first laminate and the second laminate, and each of the first laminate and the second laminate includes an E-type linear polarizer.

The linear polarizer of the first laminate may be provided on the liquid crystal layer side of the first substrate, and the linear polarizer of the second laminate may be provided on the liquid crystal layer side of the second substrate.

The first laminate may have a first transparent electrode, a linear polarizer, a negative C plate layer, and a first alignment film provided in that order on a first substrate, and the second laminate may have a linear polarizer and a second alignment film provided in that order on a second substrate.

The first laminate may have a linear polarizer, a negative C plate layer, a first transparent electrode, and a first alignment film provided in that order on a first substrate, and the second laminate may have a linear polarizer and a second alignment film provided in that order on a second substrate.

In the first laminate, a negative C plate layer may be laminated on the adhesive layer.

Another aspect of the present invention relates to a dimming device including a first light-transmitting plate having a curved surface, a second light-transmitting plate, a dimming cell disposed between the first light-transmitting plate and the second light-transmitting plate, and an optically transparent adhesive film disposed between the curved surface of the first light-transmitting plate and the dimming cell, and adhering one side of the dimming cell to the curved surface of the first light-transmitting plate.

The second light-transmitting plate may be positioned away from the dimming cell.

The second light-transmitting plate may be attached to the dimming cell via an adhesive layer.

The space between the second light-transmitting plate and the dimming cell may be sealed with a sealant.

Silicone may be disposed between the second light-transmitting plate and the dimming cell, which are sealed with a sealant.

There may be a vacuum between the second light-transmitting plate and the dimming cell, which are sealed with a sealing material.

The light-transmitting plate may have a higher bending stiffness than the dimming cell.

The first light-transmitting plate may have a higher bending stiffness than the dimming cell.

The light control device may further include an anti-reflective layer.

The dimming device may further include an anti-reflection layer, which may be provided on at least one of the dimming cell and the light-transmitting plate.

The dimming device may further include an anti-reflection layer, which may be provided on at least one of the dimming cell and the second light-transmitting plate.

The anti-reflective layer may include at least one of an anti-glare layer, an anti-reflection layer, and a low-reflection layer.

The surface may be a three-dimensional surface.

The optically transparent adhesive film may have a thickness of 50 μm or more and 500 μm or less in the direction in which the optically transparent adhesive film and the light control cell are laminated, and a storage modulus of 1×10 ⁷ Pa or more and 1×10 ⁸ Pa or less in a room temperature environment.

The optically transparent adhesive film may have a loss tangent of 0.5 or more and 1.5 or less.

According to the present invention, the light-controlling cell is properly attached to the curved surface of the light-transmitting plate via an optically transparent adhesive film, and the light-controlling cell exhibits high light-transmitting and light-blocking performance.

FIG. 1 is a schematic cross-sectional view showing an example of a light control device. FIG. 2 is a diagram for explaining a three-dimensional curved surface. FIG. 3 is a schematic cross-sectional view for explaining the layer structure of the optically transparent adhesive film and the light control cell. FIG. 4A is a schematic cross-sectional view for explaining the layer structure of the first electrode alignment layer. FIG. 4B is a schematic cross-sectional view for explaining the layer structure of the second electrode alignment layer. FIG. 5 is a schematic cross-sectional view showing a modified example of the second polarizing plate (protective layer) and the hard coat layer. FIG. 6 is a diagram illustrating a first resin base material, a second resin base material, a polarizing layer of a first polarizing plate, and a polarizing layer of a second polarizing plate, for explaining the first arrangement mode. FIG. 7 is a diagram showing a first resin base material, a second resin base material, a polarizing layer of a first polarizing plate, and a polarizing layer of a second polarizing plate, illustrating a comparative arrangement to the first arrangement. FIG. 8 shows the viewing angle characteristics of the dimming cell for the first arrangement shown in FIG. 6 (see symbol "L1" in FIG. 8) and the viewing angle characteristics of the dimming cell for the comparative arrangement shown in FIG. 7 (see symbol "L2" in FIG. 8). FIG. 9 is a diagram showing a first resin base material, a second resin base material, a polarizing layer of a first polarizing plate, a polarizing layer of a second polarizing plate, and a retardation compensation film for explaining the second arrangement mode. FIG. 10 is a diagram showing a first resin substrate, a second resin substrate, a polarizing layer of a first polarizing plate, a polarizing layer of a second polarizing plate, and a retardation compensation film, illustrating a comparative arrangement to the second arrangement. Figure 11 shows the viewing angle characteristics of the dimming cell for the second arrangement shown in Figure 9 (see symbol "L3" in Figure 11) and the viewing angle characteristics of the dimming cell for the comparative arrangement shown in Figure 10 (see symbol "L4" in Figure 11). FIG. 12 is a table showing the evaluation of the state of bonding of the light-controlling cell (Examples 1 to 3) to the curved surface of the light-transmitting plate. FIG. 13 is a table showing the evaluation of the state of bonding of the light-controlling cell (Examples 4 to 9) to the curved surface of the light-transmitting plate. FIG. 14 is a table showing the evaluation of the state of bonding of the light-controlling cell (Examples 10 to 12) to the curved surface of the light-transmitting plate. FIG. 15 is a flow chart showing an outline of the manufacturing process of the light-control cell. FIG. 16 is a chart showing the test results used to confirm the spacer configuration. FIG. 17 is a chart showing the test results used to confirm the spacer configuration. FIG. 18 is a table showing the manufacturing conditions of the spacer. FIG. 19 is a table showing the manufacturing conditions of the alignment film. Figure 20 is a conceptual diagram to explain an example of a light-control cell using a guest-host type liquid crystal (light-blocking state), where Figure 20(a) is a cross-sectional view of the light-control cell, and Figure 20(b) is a plan view of the first polarizing plate with the absorption axis direction indicated by arrow "A". Figure 21 is a conceptual diagram for explaining the same dimming cell (light transmitting state) as Figure 20, where Figure 21(a) is a cross-sectional view of the dimming cell, and Figure 21(b) is a plan view of the first polarizing plate with the absorption axis direction indicated by arrow "A". FIG. 22 is a conceptual diagram for explaining another example (light blocking state) of a light control cell using a guest-host type liquid crystal, and shows a cross section of the light control cell. FIG. 23 is a conceptual diagram for explaining the same light control cell (light transmitting state) as in FIG. 22, and shows a cross section of the light control cell. FIG. 24 is a cross-sectional view illustrating the basic structure of a light-control cell. FIG. 25 is a cross-sectional view showing a light-controlling cell according to the first mode. FIG. 26 is a flow chart showing the manufacturing process of the light-control cell of FIG. FIG. 27 is a flow chart showing the upper laminate fabricating process in the manufacturing process of FIG. FIG. 28 is a flow chart showing the lower laminate fabricating process in the manufacturing process of FIG. FIG. 29 is a cross-sectional view showing a light-controlling cell according to the second mode of the present invention. FIG. 30 is a cross-sectional view showing a light-controlling cell according to the third mode of the present invention. FIG. 31 is a cross-sectional view showing a light-controlling cell according to the fourth mode of the present invention. FIG. 32 is a cross-sectional view showing a light-controlling cell according to the fifth mode of the present invention. FIG. 33 is a schematic cross-sectional view showing another example of a light control device. FIG. 34 is a schematic cross-sectional view showing another example of a light control device. FIG. 35 is a schematic cross-sectional view showing another example of a light control device. FIG. 36 is a schematic cross-sectional view showing an example of a light control device including an anti-reflection layer. FIG. 37 is a schematic cross-sectional view showing another example of a light control device including an antireflection layer.

Below, one embodiment of the present invention will be described with reference to the drawings.

The dimming device 10 described below can be applied to various technical fields that require adjustment of light transmittance, and the scope of application is not particularly limited. For example, the dimming device 10 according to the present invention can be used as any device that requires switching between light transmission and light blocking, such as windows (including skylights) of vehicles and other vehicles and buildings, showcases, and partitions placed indoors. Furthermore, each element that constitutes the dimming device 10 can be manufactured by known methods, and is manufactured using any lamination technology, photolithography technology, and/or bonding technology.

The dimming device 10 (dimming cell 22, etc.) described below merely illustrates one embodiment of the present invention. Therefore, for example, some of the elements listed below as components of the dimming device 10 may be replaced with other elements or may not be included. Elements not listed below may also be included as components of the dimming device 10. In addition, for the convenience of illustration and ease of understanding, some parts of the drawings have been appropriately altered or exaggerated from those of the actual objects in terms of scale and dimensional ratios.

Figure 1 is a schematic cross-sectional view showing an example of a dimming device 10.

The dimming device 10 of this embodiment includes a light-transmitting plate 21 having a curved surface 20, a dimming cell 22 with variable transmittance of light (particularly visible light), and an optically clear adhesive film (OCA) 24 disposed between the curved surface 20 of the light-transmitting plate 21 and one side of the dimming cell 22.

The light-transmitting plate 21 contains an ultraviolet-ray-blocking component and blocks the transmission of ultraviolet rays while transmitting visible light. The light-transmitting plate 21 has a curved surface 20 and includes one or more glass plates. The light-transmitting plate 21 does not necessarily need to contain an ultraviolet-ray-blocking component, and the light-control cell 22 and the optically transparent adhesive film 24 described below can be applied to a light-transmitting plate 21 that does not contain an ultraviolet-ray-blocking component. The light-transmitting plate 21 may have, for example, glass plates (two glass plates in total) arranged on the front side and the back side, or may have one glass plate such as reinforced glass. The light-transmitting plate 21 may also include a member other than a glass plate, and any functional layer such as a high-rigidity film (e.g., a COP (Cyclo Olefin Polymer) resin layer, etc.) or a heat-reflecting film may be provided on the light-transmitting plate 21.

The curved surface 20 of the light-transmitting plate 21 is typically a two-dimensional or three-dimensional curved surface, but is not particularly limited thereto, and the curved surface 20 of the illustrated light-transmitting plate 21 is a three-dimensional curved surface. In general, it is not easy to attach a thin-film dimming cell 22 to a three-dimensional curved surface without causing wrinkles, but according to the "attachment technique for the dimming cell 22 to the light-transmitting plate 21" described below, it is easy to attach a thin-film dimming cell 22 to a three-dimensional curved surface without causing wrinkles.

Figure 2 is a diagram for explaining the three-dimensional curved surface 20a. The three-dimensional curved surface 20a is to be distinguished from a two-dimensional curved surface that is curved two-dimensionally around a single axis, or a two-dimensional curved surface that is curved two-dimensionally with different curvatures around multiple parallel axes. In other words, the three-dimensional curved surface 20a means a surface that is partially or entirely curved around each of multiple axes that are inclined relative to one another.

One surface of the illustrated light-transmitting plate 21 (i.e., the curved surface 20 to which the optically transparent adhesive film 24 is attached) is curved as a whole as shown in FIG. 2, bending in a first direction d1 around a first axis A1 and also bending in a second direction d2 around a second axis A2. In the illustrated example, both the first axis A1 and the second axis A2 are inclined with respect to the X and Y directions shown in FIG. 2, and the first axis A1 is perpendicular to the second axis A2.

One side of the dimming cell 22 is adhered to the curved surface 20 of the light-transmitting plate 21 via an optically transparent adhesive film 24.

Figure 3 is a schematic cross-sectional view for explaining the layer structure of the optically transparent adhesive film 24 and the dimming cell 22. As described above, the optically transparent adhesive film 24 is provided on one side of the dimming cell 22. In addition, a hard coat layer 26 is provided on the other side of the dimming cell 22.

The optically transparent adhesive film 24 of this embodiment is composed of a transparent adhesive sheet called OCA, does not include a substrate, and can be composed only of an adhesive with a nearly constant thickness, for example, an acrylic adhesive with excellent transparency. The optically transparent adhesive film 24 (OCA) is manufactured by sandwiching the adhesive between sheets (separators (peeling materials)) with excellent peeling properties, and the laminate of the adhesive and separator is cut into the desired shape, and the adhesive (optically transparent adhesive film 24) can be attached to the desired location by removing the separator. The optically transparent adhesive film 24 can be formed, for example, by applying a transparent adhesive resin called OCR (Optical Clear Resin).

The light control cell 22 has a multi-layer structure, and as shown in FIG. 3, from the optically transparent adhesive film 24 side toward the outside (i.e., in the direction away from the light-transmitting plate 21), "protective layer 47, polarizing layer 48, protective layer 47, adhesive layer 46, first electrode alignment layer 43, liquid crystal layer 49, second electrode alignment layer 44, adhesive layer 46, retardation compensation film 45, adhesive layer 46, protective layer 47, polarizing layer 48, protective layer 47, adhesive layer 46, and hard coat layer 26" are sequentially arranged in layers. These layers form a laminated structure of "polarizing plate-electrode layer-alignment film-liquid crystal layer-alignment film-electrode layer-polarizing plate-hard coat layer".

That is, the first polarizing plate 41 is formed by the "protective layer 47, polarizing layer 48, and protective layer 47" arranged on the light-transmitting plate 21 side, and the second polarizing plate 42 is formed by another "protective layer 47, polarizing layer 48, and protective layer 47" arranged on the hard coat layer 26 side. The first polarizing plate 41 in this embodiment is attached to the curved surface 20 of the light-transmitting plate 21 via the optically transparent adhesive film 24, and the second polarizing plate 42 is arranged at a position farther away from the light-transmitting plate 21 than the first polarizing plate 41.

The polarizing layer 48 of the first polarizing plate 41 and the second polarizing plate 42 is composed of a material that performs the desired polarizing function, and is typically made by stretching PVA (polyvinyl alcohol) doped with an iodine compound. Typical arrangements of the polarizing layer 48 include a "parallel Nicol" arrangement in which the absorption axis of the polarizing layer 48 of the first polarizing plate 41 and the absorption axis of the polarizing layer 48 of the first polarizing plate 41 are parallel to each other, and a "crossed Nicol" arrangement (see Figures 6 and 9 below) in which the absorption axis of the polarizing layer 48 of the first polarizing plate 41 and the absorption axis of the polarizing layer 48 of the first polarizing plate 41 are perpendicular to each other.

The protective layer 47 serves to protect the adjacent layers and can be made of any material that is transparent to visible light, and is typically made of TAC (triacetylcellulose) or acrylic. The protective layers 47 formed at multiple locations on the first polarizing plate 41 and the second polarizing plate 42 may be made of different materials depending on the location, or may be made of the same material.

Between the first polarizer 41 and the second polarizer 42, a first electrode orientation layer 43 is disposed on the first polarizer 41 side, and a second electrode orientation layer 44 is disposed on the second polarizer 42 side, and the first electrode orientation layer 43 and the second electrode orientation layer 44 each form an "electrode layer and orientation film supported by a substrate."

Figure 4A is a schematic cross-sectional view for explaining the layer structure of the first electrode alignment layer 43. In this embodiment, the first electrode alignment layer 43 is formed by sequentially providing a hard coat layer 53, a first resin substrate 29, a hard coat layer 53, an index matching layer 55, a first electrode layer 31, and a first alignment film 33 in a layered form from the first polarizer 41 side toward the liquid crystal layer 49 side.

Figure 4B is a schematic cross-sectional view for explaining the layer structure of the second electrode alignment layer 44. In this embodiment, the second electrode alignment layer 44 is formed by sequentially providing a layered structure of the second alignment film 34, the second electrode layer 32, the index matching layer 55, the hard coat layer 53, the second resin substrate 30, and the hard coat layer 53 from the liquid crystal layer 49 side toward the second polarizer 42 side.

In this way, between the first resin film 29 and the second resin film 30, a first electrode layer 31 is disposed on the first resin film 29 side, and a second electrode layer 32 is disposed on the second resin film 30 side. The first electrode layer 31 and the second electrode layer 32 can be formed as transparent electrodes using various materials such as ITO (Indium Tin Oxide), and a power supply means such as FPC (Flexible Printed Circuits) is connected to apply a voltage. Depending on the voltage applied to the first electrode layer 31 and the second electrode layer 32, the electric field acting on the liquid crystal layer 49 disposed between the first electrode layer 31 and the second electrode layer 32 changes, and the orientation of the liquid crystal material constituting the liquid crystal layer 49 is adjusted.

Between the first electrode layer 31 and the second electrode layer 32, a first alignment film 33 is disposed on the first electrode layer 31 side, and a second alignment film 34 is disposed on the second electrode layer 32 side. The manufacturing method of the first alignment film 33 and the second alignment film 34 is not particularly limited, and the first alignment film 33 and the second alignment film 34 having liquid crystal alignment ability can be made by any method. For example, the first alignment film 33 and the second alignment film 34 may be made by performing a rubbing treatment on a resin layer such as polyimide, or the first alignment film 33 and the second alignment film 34 may be made based on a photo-alignment method in which a polymer film is irradiated with linearly polarized ultraviolet light to selectively react polymer chains in the polarization direction.

3, a spacer 52 and a sealant 36 are provided between the first alignment film 33 and the second alignment film 34 in addition to the liquid crystal layer 49. That is, a sealant 36 is provided between the first alignment film 33 and the second alignment film 34 to partition the liquid crystal space 35, and the liquid crystal layer 49 is formed by filling the liquid crystal space 35 with a liquid crystal material. A plurality of spacers 52 are arranged at least in the liquid crystal space 35 and are discretely arranged to support the first alignment film 33 and the second alignment film 34. Each spacer 52 can be composed of a single or multiple members, and may extend in the stacking direction only in the liquid crystal space 35, or may extend in the stacking direction so as to penetrate one alignment film (e.g., the second alignment film 34) and the liquid crystal space 35. The spacer 52 also has a core portion and a covering portion, and the covering portion may be in direct contact with the other alignment film (e.g., the first alignment film 33). Therefore, for example, the core portion of each spacer 52 may extend in the liquid crystal space 35 from above the second electrode layer 32, penetrating the second alignment film 34, until it reaches just before the first alignment film 33, and a covering portion made of the same components as the second alignment film 34 may be provided on the core portion, and the covering portion may come into direct contact with the first alignment film 33, thereby maintaining the distance (cell gap) between the first alignment film 33 and the second alignment film 34 by each spacer 52.

The sealant 36 prevents leakage of the liquid crystal material constituting the liquid crystal layer 49, and adheres to the first electrode alignment layer 43 (first alignment film 33) and the second electrode alignment layer 44 (second alignment film 34) to fix them to each other. The sealant 36 is generally made of a thermosetting epoxy resin, and when the liquid crystal material is filled into the liquid crystal space 35 by vacuum injection, the sealant 36 made of epoxy resin can be used. When the ODF (One Drop Fill) method is used as the filling method for the liquid crystal material, a hybrid type material having both thermosetting and UV curing properties (ultraviolet ray curing properties) can be used as the sealant 36. This is because liquid crystal touching the uncured sealant 36 induces defects in appearance. Therefore, it is preferable that the material constituting the sealant 36 (the compositional components of the sealant 36) contains, for example, an ultraviolet ray curing acrylic resin and an epoxy resin. From the viewpoint of fixing the first electrode alignment layer 43 (first alignment film 33) and the second electrode alignment layer 44 (second alignment film 34) to each other while preventing leakage of the liquid crystal material, the hardness (hardness) of the sealant 36 is preferably 20 to 90 at the maximum point measured with a durometer (type A in accordance with JIS K6253; 10N load), and more preferably 20 to 50. The glass transition point (glass transition temperature (Tg)) of the sealant 36 is preferably 0°C to 60°C, and more preferably 0°C to 40°C.

In addition, a plurality of spacers 52 are arranged between the first electrode alignment layer 43 (first alignment film 33) and the second electrode alignment layer 44 (second alignment film 34) to determine the thickness of the liquid crystal layer 49 (i.e., the distance between the first electrode alignment layer 43 (first alignment film 33) and the second electrode alignment layer 44 (second alignment film 34)). Each spacer 52 can be made of various resin materials and may have a columnar shape such as a truncated cone, or a spherical bead shape. The columnar liquid crystal space 35 can be formed at the desired location based on photolithography technology, and the bead-shaped liquid crystal space 35 is made in advance and dispersed in the liquid crystal space 35.

The liquid crystal layer 49 of this embodiment has a negative pressure in the liquid crystal space 35 from the viewpoint of "improving the bonding property of the dimming cell 22 to the light-transmitting plate 21 (i.e., preventing distortion of the dimming cell 22)". For example, such a negative pressure can be realized by injecting a liquid crystal material into the liquid crystal space 35 so that the liquid crystal material constituting the liquid crystal layer 49 occupies "less than 100% (preferably about 99%) of the volume of the liquid crystal space 35". The dimming cell 22 of this embodiment is attached to the curved surface 20 of the light-transmitting plate 21 in a bent state, but if the liquid crystal space 35 is filled with an excess of liquid crystal material, the flexibility of the dimming cell 22 is impaired and the attachment property of the dimming cell 22 to the light-transmitting plate 21 is deteriorated. Therefore, it is preferable to inject a liquid crystal material into the liquid crystal space 35 so that the liquid crystal material constituting the liquid crystal layer 49 occupies "about 99% of the volume of the liquid crystal space 35" to ensure the flexibility of the dimming cell 22. Note that if the amount of liquid crystal material injected is too small compared to the volume of the liquid crystal space 35, air bubbles are induced in the liquid crystal space 35, which is not preferable.

The liquid crystal layer 49 in this embodiment is a VA (Vertical Alignment) type liquid crystal layer, and adopts a type called "normally black" in which a light-blocking state is achieved when no voltage is applied to the first electrode layer 31 and the second electrode layer 32. However, the liquid crystal layer 49 may adopt other driving methods, such as a TN (Twisted Nematic) type, an IPS (In Plane Switching) type, an FFS (Fringe Field Switching) type, or other types.

Between the second polarizer 42 and the second electrode layer 32 (second electrode alignment layer 44), a phase difference compensation film 45 having compensation performance according to the driving method of the liquid crystal layer 49 is provided, and in this embodiment, a phase difference compensation film 45 for eliminating the phase difference of the liquid crystal layer 49 of the VA method is provided. Since the phase difference change due to the angle is large in the VA method, the phase difference compensation film 45 of this embodiment has compensation performance that can effectively compensate for such phase difference change. On the other hand, when the liquid crystal layer 49 adopts the TN method, the phase difference compensation film 45 has compensation performance for compensating for the phase difference of the liquid crystal layer 49 of the TN method (for example, the angle dependency of the liquid crystal molecules). In the case of the IPS method liquid crystal layer 49, the phase difference is generally small and the phase difference change due to the angle is also small, so basically a phase difference compensation film is often not required, and the phase difference compensation film 45 does not need to be provided.

The retardation compensation film 45 is not necessarily an essential element and does not have to be provided in the dimming cell 22, and the installation position is not limited as long as the desired compensation performance can be achieved. Typically, the retardation compensation film 45 is provided at least one of "between the first polarizing plate 41 and the first electrode layer 31 (first electrode orientation layer 43)" and "between the second polarizing plate 42 and the second electrode layer 32 (second electrode orientation layer 44)". Therefore, the retardation compensation film 45 may be provided between the first polarizing plate 41 (protective layer 47) and the first electrode orientation layer 43 (hard coat layer 53) instead of the position shown in FIG. 3 (i.e., between the second electrode orientation layer 44 (hard coat layer 53) and the second polarizing plate 42 (protective layer 47)). The retardation compensation film 45 may be provided in two or more layers (i.e., in two or more places), and it is sufficient if the retardation compensation film 45 as a whole can compensate for the phase difference of the liquid crystal layer 49.

The hard coat layer 26 is provided at a position farther away from the light transmission plate 21 than the second polarizing plate 42, and forms the outermost layer of the dimming cell 22 of this embodiment. The illustrated hard coat layer 26 is fixed to the second polarizing plate 42 via an adhesive layer 46 and can contain any component. For example, the hard coat layer 26 can be formed of the same component as the protective layer 47 (e.g., TAC, etc.). The hard coat layer 26 may be formed directly on the surface of the second polarizing plate 42 (protective layer 47 in this embodiment) as shown in FIG. 5. For example, a cured film containing fine particles (e.g., titanium dioxide, etc.) may be formed on the surface of the second polarizing plate 42 (on the protective layer 47) using a silicone-based ultraviolet curing resin to function as the hard coat layer 26.

The above-mentioned functional layers (the first polarizing plate 41, the first electrode alignment layer 43, the second electrode alignment layer 44, the retardation compensation film 45, the second polarizing plate 42, and the hard coat layer 26 shown in FIG. 3) are bonded to adjacent functional layers by an adhesive layer 46, and have an integrated laminated structure. The components constituting this adhesive layer 46 are not particularly limited, and the components of the adhesive layer 46 may be determined according to the characteristics of each layer to be bonded. In this embodiment, all adhesive layers 46 are made of the same material as the optically transparent adhesive film (i.e., OCA) 24, but an adhesive layer 46 containing other components such as an ultraviolet curing resin may be used, or an adhesive layer 46 containing a component different from that of the adhesive layer 46 at other locations may be used depending on the placement position and the adhesive target.

The layer structure of the light-transmitting plate 21, the optically transparent adhesive film 24, and the dimming cell 22 shown in FIG. 3 and the like is merely an example, and other functional layers may be provided as part of the dimming cell 22, or other functional parts may be additionally provided to the dimming cell 22. For example, although not shown, a seal protective material that functions as a protective material can be provided from the side of the dimming cell 22 and the optically transparent adhesive film 24 to a part of the curved surface 20 of the light-transmitting plate 21. This seal protective material can not only reinforce the adhesive strength of the dimming cell 22 and the optically transparent adhesive film 24 to the light-transmitting plate 21, but also reinforce the adhesive strength between adjacent layers of the dimming cell 22 and the optically transparent adhesive film 24.

As a result of extensive research, the inventors of the present invention have come to the conclusion that in order to bond a thin-film dimming cell 22 to a curved surface 20 (especially a three-dimensional curved surface) without wrinkles or other distortions, it is preferable to adjust the dimming cell 22 and the optically transparent adhesive film 24 so as to satisfy the following conditions.

That is, the optically transparent adhesive film 24 has a thickness in the direction in which the optically transparent adhesive film 24 and the dimming cell 22 are laminated of 50 μm or more and 500 μm or less, preferably 200 μm or more and 300 μm or less, and more preferably has a storage modulus in a room temperature environment of 1 × 10 ⁷ Pa or more and 1 × 10 ⁸ Pa or less. The loss tangent (tan δ) of the optically transparent adhesive film 24 is preferably 0.5 or more and 1.5 or less, more preferably 0.7 or more and 1.2 or less.

The optically transparent adhesive film 24 not only serves to bond the curved surface 20 of the light-transmitting plate 21 to the first polarizing plate 41 (protective layer 47), but also serves as a cushion to fill the difference in curvature between the curved surface 20 of the light-transmitting plate 21 and the first polarizing plate 41 (protective layer 47). Therefore, if the thickness of the optically transparent adhesive film 24 in the stacking direction is too small, it becomes difficult to properly fulfill its role as a cushion, while if the thickness in the stacking direction is too large, it becomes difficult to properly fix the first polarizing plate 41 (protective layer 47) to the curved surface of the light-transmitting plate 21. In addition, if the storage modulus of the optically transparent adhesive film 24 is too large, the rigidity of the entire light-controlling cell 22 increases, resulting in insufficient conformity to the curved surface whose shape changes three-dimensionally. On the other hand, if the storage modulus of the optically transparent adhesive film 24 is too small, the optically transparent adhesive film 24 becomes too fluid, making it difficult to properly fix the first polarizing plate 41 (protective layer 47) to the curved surface of the light-transmitting plate 21, and there is a concern that reliability such as heat resistance will be insufficient and foaming will occur even in normal usage environments. Furthermore, if the storage modulus of the optically transparent adhesive film 24 is too small, the processability of the optically transparent adhesive film 24 will be poor, and for example, unwanted separation of the optically transparent adhesive film 24 may occur due to glue overflow when the optically transparent adhesive film 24 is cut. Therefore, the present inventor has newly discovered that in order to properly attach the light control cell 22 to the curved surface 20 without causing distortion such as wrinkles, it is preferable that the thickness and storage modulus of the optically transparent adhesive film 24 in the lamination direction are within the above ranges.

The first resin substrate 29 and the second resin substrate 30 can be made of various transparent film materials, and are preferably made of a film material with small optical anisotropy, such as COP. In particular, from the viewpoint of appropriately attaching the dimming cell 22 to the curved surface 20, it is preferable that at least one of the first resin substrate 29 and the second resin substrate 30 contains polycarbonate. The constituent materials, shapes and/or sizes of the first resin substrate 29 and the second resin substrate 30 may be the same as or different from each other.

The length of the sealing material 36 in the direction perpendicular to the stacking direction (the direction in which the first alignment film 33, the sealing material 36, and the second alignment film 34 are stacked) (i.e., the width direction) is preferably 1 mm or more and 5 mm or less, and is particularly preferably 1.5 mm.

The smaller the widthwise length of the sealant 36, the lower the rigidity of the entire dimming cell 22, making it easier to bond the dimming cell 22 to the curved surface 20 without causing distortion such as wrinkles. On the other hand, if the widthwise length of the sealant 36 is too small, the original functions of the sealant 36, such as "sealing the liquid crystal layer 49 in the liquid crystal space 35" and "bonding the first electrode alignment layer 43 (first alignment film 33) and the second electrode alignment layer 44 (second alignment film 34)", are impaired. Taking all these factors into consideration, the present inventors have newly discovered that the widthwise length of the sealant 36 is preferably 1 mm or more and 5 mm or less (more preferably 1.5 mm) as described above.

Thus, generally speaking, the smaller the rigidity of the laminate constituting the dimming cell 22, the easier it is to deform in accordance with the curved surface 20 of the light-transmitting plate 21, and the easier it is to bond the dimming cell 22 to the curved surface 20 without causing distortion such as wrinkles. However, the present inventors have newly discovered that the dimming cell 22 cannot be properly bonded to the curved surface 20 of the light-transmitting plate 21 simply because the rigidity of the laminate is sufficiently small, and that suitable conditions exist for the optically transparent adhesive film 24 and the dimming cell 22.

The light transmittance (particularly the total light transmittance) of the dimming cell 22 is preferably 30% or more, and more preferably 35% or more. The "total light transmittance" here refers to the ratio of the total transmitted light flux to the parallel incident light flux of the test piece, and in the case of a diffusive sample, the "total transmitted light flux" includes the diffused transmitted light flux (diffused component). The details of the total light transmittance can be determined based on "JIS (Japanese Industrial Standards) 7375:2008". The total light transmittance can be calculated from the "proportion of light transmitted through the dimming cell 22" obtained based on the light intensity of a wavelength of 555 nm of the light before passing through the dimming cell 22. In addition, the color of the dimming cell 22 is preferably "black" in consideration of harmony with other surrounding components, but it is also preferable for it to be "achromatic color other than black".

In addition, distortions such as wrinkles of the dimming cell 22 caused by bonding to the curved surface 20 of the light-transmitting plate 21 are particularly likely to occur at the beginning of the bonding process (i.e., the bonding start area). Based on this knowledge, the dimming cell 22 is bonded to the curved surface 20 of the light-transmitting plate 21 at a location in the dimming device 10 (light-transmitting plate 21, optically transparent adhesive film 24, and dimming cell 22) that is not originally intended for optical use or that is difficult for the user to see, as the bonding start area, thereby reducing the substantial effect of distortion of the dimming cell 22. Therefore, for example, by setting the bonding start area to an area outside the seal material 36 where the liquid crystal layer 49 is not provided, the "effect of distortion occurring in the dimming cell 22" on the light passing through the liquid crystal layer 49 can be substantially reduced. Therefore, when the first electrode orientation layer 43 and the second electrode orientation layer 44 (particularly the first electrode layer 31 and the second electrode layer 32) are extended outside the seal material 36 and a "power supply means for the first electrode layer 31 and the second electrode layer 32" such as an FPC is connected to this extension, the "area where the power supply means is connected" can be used as a bonding start area, and the dimming cell 22 can be bonded to the curved surface 20 of the light-transmitting plate 21 from that area, thereby effectively hiding the distortion occurring in the dimming cell 22. In particular, the position where the power supply means such as an FPC is connected among the extended parts of the first electrode layer 31 and the second electrode layer 32 is relatively far from the area (active area) where the liquid crystal layer 49 is provided, so that the distortion of the dimming cell 22 occurring in the bonding start area can be easily contained within the range of the inactive area.

As described above, according to the dimming device 10 of this embodiment, the dimming cell 22 can be appropriately attached to the curved surface 20 of the light-transmitting plate 21 via the optically transparent adhesive film 24 without distortion. In particular, according to the dimming cell 22 of this embodiment, dimming control is performed by a combination of the polarizing plates (first polarizing plate 41 and second polarizing plate 42) and the orientation control of the liquid crystal layer 49, so that high-level light transmission and light blocking performance can be achieved with a simple configuration.

The dimming cell 22 of this embodiment does not include rigid elements such as glass, and is composed of a combination of flexible materials. Therefore, the dimming cell 22 of this embodiment can be precisely attached to the curved surface 20, which is difficult when glass is used as the base material supporting the first electrode layer 31 and the second electrode layer 32.

In general, the rigidity of a dimming cell using a resin substrate is low, and such a low-rigidity dimming cell is relatively easily deformed when an external force is applied directly, and the optical properties of the liquid crystal layer are disturbed. Therefore, if a dimming device is used in an environment where an external force such as vibration is applied suddenly or continuously to a low-rigidity dimming cell, the orientation of the liquid crystal material of the liquid crystal layer is disturbed and the original optical function cannot be fully exerted, and phenomena such as flickering may occur in the light observed through the dimming device. However, the dimming cell 22 (liquid crystal layer 49) of this embodiment is firmly supported by being attached to a light-transmitting plate 21 with a relatively high rigidity (i.e., a light-transmitting plate 21 with a higher bending rigidity than the dimming cell 22), so that the disturbance of the liquid crystal orientation caused by the external force can be effectively reduced, and phenomena such as flickering can be avoided.

As a mode of attaching the dimming cell 22 to the light-transmitting plate 21 having two or more glass plates, there are a mode in which the dimming cell 22 is arranged between two glass plates, and a mode in which the dimming cell 22 is arranged on the outside of the two glass plates. When the dimming cell 22 is arranged between two glass plates, it is possible to adjust the transmittance of light incident on the glass plate by the dimming cell 22 while protecting the dimming cell 22 with the glass plate. However, while a relatively large force (compressive force, shear force, etc.) may be applied between the two glass plates, the dimming cell 22 having the polarizing plate (first polarizing plate 41 and second polarizing plate 42) does not necessarily have high resistance to the force applied from the outside. In addition, the temperature between the glass plates may become very high depending on the usage environment, but the polarizing plate does not necessarily have excellent high temperature resistance. Therefore, when the dimming cell 22 having the polarizing plate is arranged between two glass plates, there is a concern that the dimming cell 22 may be crushed or deteriorated, and the dimming cell 22 may not be able to perform the desired dimming function.

On the other hand, in the embodiment shown in FIG. 1 and FIG. 3, in which the dimming cell 22 is attached to the outer surface of the light-transmitting plate 21, the strength and temperature resistance required for the dimming cell 22 are not high. Therefore, in the embodiment, the dimming cell 22 is equipped with polarizing plates (first polarizing plate 41 and second polarizing plate 42), but the dimming cell 22 can continuously perform the desired dimming function. In addition, by using a dimming cell 22 that satisfies the above-mentioned conditions that make it easy to attach the dimming cell 22 to the curved surface 20 without causing distortion such as wrinkles, the dimming cell 22 can be appropriately attached to the light-transmitting plate 21 according to the specific curvature of the curved surface 20, which may have various shapes, without excessively impairing the light-transmitting and light-shielding performance of the dimming cell 22.

<Directivity of absorption axis of polarizing plate and optical axis of substrate in VA mode>
When the driving method of the liquid crystal layer 49 is the VA method, the following relationship exists regarding "the direction of the absorption axis of the polarizing layer 48 of the first polarizing plate 41 and the second polarizing plate 42" and "the direction of the optical axis of the substrate (first resin substrate 29 and second resin substrate 30) of the first electrode alignment layer 43 and the second electrode alignment layer 44."

<First Arrangement>
FIG. 6 is a diagram illustrating a first resin base material 29, a second resin base material 30, a polarizing layer 48 of a first polarizing plate 41, and a polarizing layer 48 of a second polarizing plate 42, for illustrating the first arrangement mode.

In this embodiment, the optical axis of the first resin base material 29 is perpendicular to the optical axis of the second resin base material 30 (see optical axis directions "Db1", "Db2" in Figure 6), the absorption axis of the polarizing layer 48 of the first polarizing plate 41 is perpendicular to the absorption axis of the polarizing layer 48 of the second polarizing plate 42 (see absorption axis directions "Da1", "Da2" in Figure 6), the optical axis direction Db1 of the first resin base material 29 is parallel to the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41, and the optical axis direction Db2 of the second resin base material 30 is parallel to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42.

As described above, by arranging the first resin base material 29 and the second resin base material 30 so that "the optical axis direction Db1 of the first resin base material 29 is perpendicular to the optical axis direction Db2 of the second resin base material 30," the phase difference imparted to the transmitted light by the first resin base material 29 can be canceled by the phase difference imparted by the second resin base material 30. Therefore, the phase difference imparted to the transmitted light by the first resin base material 29 and the second resin base material 30 can be reduced overall.

In addition, by arranging the first resin base material 29, the second resin base material 30, the first polarizing plate 41, and the second polarizing plate 42 so that the optical axis direction Db1 of the first resin base material 29 is parallel to the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41, and the optical axis direction Db2 of the second resin base material 30 is parallel to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42, it is possible to suppress the deterioration of the viewing angle characteristics and the light blocking rate during light blocking (i.e., during black display) caused by the optical anisotropy of the first resin base material 29 and the second resin base material 30. In other words, the resin base material (the first resin base material 29 and the second resin base material 30) that originally has optical anisotropy affects the transmitted light, and in particular, in the light control cell 22 (light control device 10) having the VA type liquid crystal layer 49, it deteriorates the viewing angle and the light blocking rate during light blocking. On the other hand, as in this embodiment, "the optical axis directions Db1, Db2 of the first resin base material 29 and the second resin base material 30 arranged in front of and behind the liquid crystal layer 49 in the stacking direction are perpendicular to each other" and "the optical axis directions of the base materials arranged on the same side through the liquid crystal layer 49 and the absorption axis directions of the polarizing plates (i.e., "the optical axis direction Db1 of the first resin base material 29 and the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41" and "the optical axis direction Db2 of the second resin base material 30 and the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42") are parallel," thereby preventing deterioration of the viewing angle and light blocking rate during light blocking.

Figure 7 is a diagram showing the first resin base material 29, the second resin base material 30, the polarizing layer 48 of the first polarizing plate 41, and the polarizing layer 48 of the second polarizing plate 42, showing a comparative embodiment to the first arrangement embodiment. In the comparative embodiment shown in Figure 7, the optical axis direction Db1 of the first resin base material 29 is perpendicular to the optical axis direction Db2 of the second resin base material 30, the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41 is perpendicular to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42, the optical axis direction Db1 of the first resin base material 29 is perpendicular to the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41, and the optical axis direction Db2 of the second resin base material 30 is perpendicular to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42.

Figure 8 shows the viewing angle characteristic of the dimming cell 22 in the first arrangement shown in Figure 6 (see symbol "L1" in Figure 8) and the viewing angle characteristic of the dimming cell 22 in the comparative arrangement shown in Figure 7 (see symbol "L2" in Figure 8). The viewing angle characteristics L1 and L2 shown in Figure 8 were obtained by measuring the transmittance while changing the azimuth angle with a polar angle of 60 degrees in a light-shielded state (i.e., power-off state) using the dimming device 10 having the configuration shown in Figures 1, 3, 4A, and 4B. The horizontal axis of Figure 8 indicates the azimuth angle (°), and the vertical axis indicates the total light transmittance (%) including the diffuse component. Note that "azimuth angle = 0°" shown in Figure 8 corresponds to one side of the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41.

The "total light transmittance" here indicates the ratio of the total transmitted light flux to the parallel incident light flux of the test piece, and in the case of a diffusive sample, the "total transmitted light flux" includes the diffused transmitted light flux (diffused component). The details of the total light transmittance can be determined based on "JIS (Japanese Industrial Standards) 7375:2008". A "halogen lamp with a dichroic mirror" was used as the light source for measuring the total light transmittance. The total light transmittance is calculated based on the "proportion of light transmitted through the dimming cell 22" obtained based on the light intensity of the 555 nm wavelength of the light before passing through the dimming cell 22 to be measured. Therefore, the total light transmittance can be expressed by the value (%) of the light intensity of the visible light wavelength after passing through the dimming cell 22 when the light intensity of the 555 nm wavelength before passing through the dimming cell 22 is expressed as "100 (%)". The thickness of the dimming cell 22 used in the measurement was approximately 0.55 mm, and the measurement device used was a haze meter HM-150 from Murakami Color Research Institute.

As is clear from FIG. 8, the first arrangement shown in FIG. 6 (see symbol "L1" in FIG. 8) can reduce the amount of variation in transmittance associated with changes in azimuth angle compared to the comparative arrangement shown in FIG. 7 (see symbol "L2" in FIG. 8), and can provide a dimming cell 22 (dimming device 10) with excellent viewing angle characteristics.

In addition, with regard to the magnitude of the transmittance (total light transmittance) itself, the transmittance L1 of the dimming cell 22 according to the first arrangement mode is generally smaller than the transmittance L2 of the dimming cell 22 according to the comparative embodiment, and it is found that the dimming cell 22 according to the first arrangement mode can exhibit excellent light blocking performance.

<Second Arrangement>
Figure 9 is a diagram showing the first resin base material 29, the second resin base material 30, the polarizing layer 48 of the first polarizing plate 41, the polarizing layer 48 of the second polarizing plate 42, and the phase difference compensation film 45a to explain the second arrangement mode.

In this embodiment, a retardation compensation film 45a is provided between the first polarizing plate 41 and the first electrode alignment layer 43. This retardation compensation film 45a is adhered to the first polarizing plate 41 (protective layer 47) via an adhesive layer (OCA) 46, and is adhered to the first electrode alignment layer 43 (hard coat layer 53 (see FIG. 4A)) via another adhesive layer (OCA) 46, and functions as an A plate. In the retardation compensation film 45a functioning as an A plate, the refractive index (nx) in the x direction in the film plane is greater than the refractive index (ny) in the y direction perpendicular to the x direction, and the refractive index (nz) in the z direction perpendicular to the x and y directions is equal to the refractive index (ny) in the y direction (i.e., the relationship "nx>ny=nz" is satisfied). The material constituting the retardation compensation film 45a is not particularly limited, but the retardation compensation film 45a of this embodiment is composed of a biaxially stretched transparent film made by COP.

The optical axis of the first resin base material 29 is parallel to the optical axis of the second resin base material 30 (see optical axis directions "Db1", "Db2" in Figure 9), the absorption axis of the polarizing layer 48 of the first polarizing plate 41 is perpendicular to the absorption axis of the polarizing layer 48 of the second polarizing plate 42 (see absorption axis directions "Da1", "Da2" in Figure 9), the optical axis direction Db1 of the first resin base material 29 is perpendicular to the direction Da1 of the absorption axis of the polarizing layer 48 of the first polarizing plate 41, and the optical axis direction Db2 of the second resin base material 30 is parallel to the direction Da2 of the absorption axis of the polarizing layer 48 of the second polarizing plate 42.

As described above, by arranging the first resin film 29 and the second resin film 30 so that the optical axis direction Db1 of the first resin film 29 and the optical axis direction Db2 of the second resin film 30 are parallel (matched), the first resin film 29 and the second resin film 30 can be continuously supplied while being unwound from the roll. Generally, the first resin film 29 and the second resin film 30 are formed in a rolled state, unwound from the roll in sequence, and cut into shapes and sizes according to each dimming cell 22 for use. On the other hand, the resin substrate is given optical anisotropy by the stretching process in the manufacturing process, such that the stretching direction is the direction of the optical axis, and in the rolled state, the longitudinal direction (i.e., the unwound direction) is generally the direction of the optical axis. Therefore, in the case where the optical axis direction Db1 of the first resin substrate 29 and the optical axis direction Db2 of the second resin substrate 30 coincide with each other as in this arrangement, the first resin substrate 29 unwound from the roll and the second resin substrate 30 unwound from the roll can be continuously superimposed while being unwound without adjusting the direction. Therefore, for example, by disposing the hard coat layer 53, the index matching layer 55, the first electrode layer 31, the second electrode layer 32, the first alignment film 33, and the second alignment film 34 as shown in FIG. 4A and FIG. 4B on the first resin substrate 29 and the second resin substrate 30 unwound from the roll, it is possible to prepare a long first electrode alignment layer 43 and a long second electrode alignment layer 44, and it is possible to efficiently mass-produce a large-area light control cell 22.

In addition, when the first resin base material 29 and the second resin base material 30 are arranged so that "the optical axis direction Db1 of the first resin base material 29 and the optical axis direction Db2 of the second resin base material 30 are parallel (matched)", the optical anisotropy of the first resin base material 29 and the second resin base material 30 strongly affects the transmitted light of the dimming cell 22, and may deteriorate the viewing angle characteristics and the light blocking rate, for example, when blocking light (i.e., when displaying black). In order to suppress such deterioration of the viewing angle characteristics and the light blocking rate, in this arrangement, the second resin base material 30 and the polarizing layer 48 of the second polarizing plate 42 are arranged so that the optical axis direction Db2 of the second resin base material 30 and the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42 are parallel. In addition, the retardation compensation film 45a and the second resin base material 30 are arranged so that the slow axis direction Dc of the retardation compensation film 45a and the optical axis direction Db2 of the second resin base material 30 are parallel. The polarizing layer 48 of the first polarizing plate 41 and the polarizing layer 48 of the second polarizing plate 42 are arranged so that the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41 is perpendicular to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42. This makes it possible to suppress "deterioration of the viewing angle characteristics and deterioration of the light blocking rate during light blocking (i.e., during black display)" caused by the optical anisotropy of the first resin base material 29 and the second resin base material 30.

9, a retardation compensation film 45a functioning as an A plate may be provided between the second resin substrate 30 and the polarizing layer 48 of the second polarizing plate 42, rather than between the first resin substrate 29 and the polarizing layer 48 of the first polarizing plate 41. In this case,
The components are arranged so that the slow axis direction Dc of the retardation compensation film 45a is parallel to the optical axis direction Db1 of the first resin base material 29, the optical axis direction Db2 of the second resin base material 30, and the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41. Even with this arrangement, it is possible to suppress "deterioration of the viewing angle characteristics and deterioration of the light blocking rate during light blocking (i.e., during black display)" caused by the optical anisotropy of the first resin base material 29 and the second resin base material 30.

Figure 10 is a diagram showing a first resin substrate 29, a second resin substrate 30, a polarizing layer 48 of a first polarizing plate 41, a polarizing layer 48 of a second polarizing plate 42, and a retardation compensation film 45a showing a comparative embodiment to the second arrangement embodiment. In the comparative embodiment shown in Figure 10, the optical axis direction Db1 of the first resin substrate 29 is parallel to the optical axis direction Db2 of the second resin substrate 30, and the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41 is perpendicular to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42, but the optical axis direction Db1 of the first resin substrate 29 is parallel to the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41, and the optical axis direction Db2 of the second resin substrate 30 is perpendicular to the absorption axis direction Da2 of the polarizing layer 48 of the second polarizing plate 42.

Figure 11 shows the viewing angle characteristic of the dimming cell 22 for the second arrangement shown in Figure 9 (see symbol "L3" in Figure 11) and the viewing angle characteristic of the dimming cell 22 for the comparative arrangement shown in Figure 10 (see symbol "L4" in Figure 11). The viewing angle characteristics L3 and L4 shown in Figure 11 were obtained by using a dimming device 10 in which a retardation compensation film 45a (see Figures 9 and 10) was arranged instead of the retardation compensation film 45 (see Figure 3) in the configuration shown in Figures 1, 3, 4A and 4B, and measuring the transmittance while changing the azimuth angle with a polar angle of 60 degrees in a light-shielding state (i.e., power OFF state). The horizontal axis of Figure 11 indicates the azimuth angle (°), and the vertical axis indicates the total light transmittance (%) including the diffusion component. The "azimuth angle = 0°" shown in Figure 11 corresponds to one side of the absorption axis direction Da1 of the polarizing layer 48 of the first polarizing plate 41. The total light transmittance was measured in the same manner as shown in Figure 8 above.

As is clear from FIG. 11, the second arrangement shown in FIG. 9 (see reference symbol "L3" in FIG. 11) can reduce the amount of variation in transmittance associated with changes in azimuth angle compared to the comparative arrangement shown in FIG. 10 (see reference symbol "L4" in FIG. 11), and can provide a dimming cell 22 (dimming device 10) with excellent viewing angle characteristics.

In addition, with regard to the magnitude of the transmittance (total light transmittance) itself, the transmittance L3 of the dimming cell 22 according to the second arrangement is generally smaller than the transmittance L4 of the dimming cell 22 according to the comparative arrangement, which shows that the dimming cell 22 according to the second arrangement can exhibit excellent light blocking performance.

<Example>
Next, various examples relating to the verification results of the bonding performance of the light-control cell 22 to the light-transmitting plate 21 will be described.

Figure 12 is a table showing the evaluation of the state of bonding of the dimming cell 22 (Examples 1 to 3) to the curved surface 20 of the light-transmitting plate 21.

The dimming devices 10 of Examples 1 and 3 use the same dimming cells 22, but the planar size (X-direction size and Y-direction size perpendicular to the stacking direction) of the light-transmitting plate 21, the thickness (length in the stacking direction (Z-direction size)), and the curvature of the curved surface 20 of the light-transmitting plate 21 are different. Note that "1800R" in FIG. 12 indicates the curvature of the curve described by a circle with a radius of 1800 mm, and "1400R" indicates the curvature of the curve described by a circle with a radius of 1400 mm.

The dimming cell 22 used in the dimming device 10 of Examples 1 and 3 has a planar size (X-direction size and Y-direction size perpendicular to the lamination direction) of 280 mm (X-direction size) and 288 mm (Y-direction size), a thickness (length in the lamination direction (Z-direction size)) of 0.63 mm, polycarbonate is used as the substrate (see the first resin substrate 29 and the second resin substrate 30 in FIG. 3), an ITO film using this polycarbonate substrate is used as the electrode substrate, a dye-based and iodine-based polarizing element that has a proven track record in liquid crystal displays (LCDs) and car navigation applications is used as the polarizing layer (see the polarizing layer 48 in FIG. 3), a large number of bead-like spacers with a diameter of 6 μm and randomly arranged are used as the spacers (see the spacer 52 in FIG. 3) provided in the liquid crystal layer 49, and a hybrid sealant 36 containing a UV-curable resin and a thermosetting resin and having a width length (length perpendicular to the lamination direction) of 1.5 mm is used.

On the other hand, in the dimming device 10 of Example 2, the same light-transmitting plate 21 as in Example 3 was used, and the planar size (X-direction size and Y-direction size perpendicular to the stacking direction) was 423 mm (X-direction size) and 337 mm (Y-direction size), and the thickness (length in the stacking direction (Z-direction size)) was 0.7 mm. The dimming cell 22 used in the dimming device 10 of Example 2 has a planar size (X-direction size and Y-direction size perpendicular to the stacking direction) of 280 mm (X-direction size) and 280 mm (Y-direction size), a thickness (length in the stacking direction (Z-direction size)) of 0.54 mm, a COP is used as the substrate (see the first resin substrate 29 and the second resin substrate 30 in FIG. 3), a COP biaxial plate for VA compensation is used as the optical compensation film of the polarizing plate (see the polarizing layer 48 in FIG. 3), a plurality of columnar spacers having a cross-sectional diameter of 15 μm and spaced apart at a pitch of 230 μm are used as spacers (see the spacer 52 in FIG. 3) provided in the liquid crystal layer 49, and a seal material 36 having a width length (length perpendicular to the stacking direction) of 5 mm is used. The other configurations of the dimming cell 22 of Example 2 were the same as those of the dimming cell 22 of Examples 1 and 3 described above.

The other configurations of the dimming device 10 in Examples 1 to 3 were similar to the configuration shown in Figure 3.

When the state of attachment of the dimming cell 22 to the light-transmitting plate 21 in the dimming devices 10 of Examples 1 to 3 described above was visually confirmed, no noticeable distortion (wrinkles, etc.) occurred in the dimming cells 22 of Examples 1 and 3, whereas wrinkles were noticeable in the dimming cell 22 of Example 2, and the dimming cell 22 could not be properly attached to the light-transmitting plate 21.

Figure 13 is a table showing the evaluation of the state of bonding of the dimming cell 22 (Examples 4 to 9) to the curved surface 20 of the light-transmitting plate 21.

In Examples 4 to 9, a "light-controlling cell 22 having different characteristics" was attached to a "light-transmitting plate 21 having the same characteristics" via an "optically transparent adhesive film 24 having the same characteristics", and the state of the light-controlling cell 22 attached to the light-transmitting plate 21 was evaluated. Specifically, the light-transmitting plate 21 had a planar size of 423 mm (length in the X direction) and 337 mm (length in the Y direction), and a thickness (length in the Z direction) of 0.7 mm.

The dimming cell 22 mainly has the substrate (see the first resin substrate 29 in FIG. 4A and the second resin substrate 30 in FIG. 4B), the shape of the spacer 52, the width of the sealant 36 (see "seal width" in FIG. 13), the first polarizing plate 41 (see in particular "polarizing layer 48" in FIG. 3), and the second polarizing plate 42 (see in particular "polarizing layer 48" in FIG. 3) appropriately changed as shown in FIG. 13.

The "Substrate" item in Figure 13 indicates the components of the substrate that were actually used, and COP (Examples 4, 6, and 7) or polycarbonate (Examples 5, 8-9) were used.

In the "Spacer" section of Figure 13, "columnar" indicates that multiple cylindrical spacers 52 with a cross-sectional diameter of 15 μm are arranged at a pitch of 230 μm, and "bead-like" indicates that multiple spherical spacers 52 with a diameter of 6 μm are arranged randomly.

In the "seal width" of FIG. 13, "5 mm (+ margin 5 mm)" indicates that the length of the seal material 36 in the direction perpendicular to the stacking direction is 5 mm, and the first electrode alignment layer 43 and the second electrode alignment layer 44 protrude by 5 mm in the direction perpendicular to the stacking direction on the opposite side of the seal material 36 from the liquid crystal layer 49. Also, "1.5 mm (+ margin 0 mm)" indicates that the length of the seal material 36 in the direction perpendicular to the stacking direction is 1.5 mm, and the first electrode alignment layer 43 and the second electrode alignment layer 44 protrude by 0 mm in the direction perpendicular to the stacking direction on the opposite side of the seal material 36 from the liquid crystal layer 49 (i.e., the first electrode alignment layer 43 and the second electrode alignment layer 44 do not protrude from the seal material 36).

In FIG. 13, "first polarizer" refers to the components of the polarizing layer 48 of the first polarizer 41, and "second polarizer" refers to the components of the polarizing layer 48 of the second polarizer 42. "Iodine-based (with COP biaxial compensation plate)" in FIG. 13 refers to the polarizing layer 48 being made of an iodine-based polarizer to which a COP plate having biaxial optical compensation performance is attached, "iodine-based" refers to the polarizing layer 48 being made of an iodine-based polarizer (without optical compensation plate), and "dye-based" refers to the polarizing layer 48 being made of a dye-based polarizer (without optical compensation plate).

"Lamination state" in FIG. 13 indicates the state of the dimming cell 22 laminated to the curved surface 20 of the light-transmitting plate 21 via the optically transparent adhesive film 24 (particularly the degree and presence or absence of distortion such as wrinkles). "Very Bad" (Example 4) indicates that very noticeable wrinkles have occurred on the dimming cell 22, a cylindrical wrinkled portion called tunneling has been formed on the dimming cell 22, and the dimming cell 22 is in a state where it cannot be used practically. "Bad" (Example 5) indicates that noticeable wrinkles have occurred on the dimming cell 22, tunneling has been formed on the dimming cell 22, and the dimming cell 22 is in a state where it is not easy to use practically. "Average" (Example 6) indicates that the wrinkles on the dimming cell 22 are not noticeable, but small tunneling has been formed on the dimming cell 22. "Good" (Example 7) indicates that slight, unnoticeable wrinkles were formed in the dimming cell 22, but no tunneling was formed, and the dimming cell 22 was in a usable state. "Excellent" (Examples 8-9) indicates that no wrinkles or other distortions were found in the dimming cell 22, the dimming cell 22 was attached to the light-transmitting plate 21 in a very good state, and the dimming cell 22 exhibited good light-transmitting and light-blocking performance.

The other configurations of the dimming device 10 in Examples 4 to 9 were similar to the configuration shown in Figure 3.

From the results shown in FIG. 13, it can be seen that the bonding state of the dimming cell 22 is improved in the dimming device 10 of Examples 5 to 7 compared to the dimming device 10 of Example 4. The dimming cell 22 of Example 5 has the same configuration as the dimming cell 22 of Example 4, except that polycarbonate is used instead of COP as the base material (see the first resin base material 29 in FIG. 4A and the second resin base material 30 in FIG. 4B). Therefore, it can be seen that polycarbonate is preferable as the constituent material of the first resin base material 29 and the second resin base material 30. The dimming cell 22 of Example 6 has the same configuration as the dimming cell 22 of Example 4, except that a "dye-based polarizer" is used instead of an "iodine-based polarizer with a COP plate having biaxial optical compensation performance" or an "iodine-based polarizer" as the polarizing layer 48 of the first polarizing plate 41 and the second polarizing plate 42. Therefore, it can be seen that a dye-based polarizer is preferable as the constituent material of the polarizing layer 48 of the first polarizing plate 41 and the second polarizing plate 42. The dimming cell 22 of Example 7 has the same configuration as the dimming cell 22 of Example 4, except that the width of the sealant 36 is 1.5 mm and there is no extension of the first electrode alignment layer 43 and the second electrode alignment layer 44 (i.e., "margin = 0 mm"). Therefore, it can be seen that the width of the sealant 36 in the direction perpendicular to the stacking direction is preferably 1.5 mm. If the width of the sealant 36 is too narrow, the dimming cell 22 may break due to a decrease in the adhesion of the sealant 36. On the other hand, if the width of the sealant 36 is too wide, the sealant 36 may not be able to follow the curved surface that changes in shape three-dimensionally insufficiently.

The dimming cells 22 of Examples 8 to 9 shown in FIG. 13 have the same configuration as the dimming cell 22 of Example 4, except that "polycarbonate is used as the constituent material of the first resin base material 29 and the second resin base material 30 (see Example 5)," "a dye-based polarizer is used as the constituent material of the polarizing layer 48 of the first polarizing plate 41 and the second polarizing plate 42 (see Example 6)," and "the width of the sealant 36 is 1.5 mm and there is no extension portion of the first electrode alignment layer 43 and the second electrode alignment layer 44 (see Example 7)." The bonding state of the dimming cells 22 of Examples 8 to 9 was better than that of the dimming cells 22 of Examples 4 to 7, so it can be inferred that the above considerations of Examples 4 to 7 are appropriate.

The dimming cell 22 of Example 8 and the dimming cell 22 of Example 9 have the same configuration except for the difference in the shape of the spacer 52. However, the bonding state of the dimming cell 22 of Example 8 and the dimming cell 22 of Example 9 was very good. Therefore, it is presumed that the shape of the spacer 52 has no or very little effect on the bonding state of the dimming cell 22.

Figure 14 is a table showing the evaluation of the state of bonding of the dimming cell 22 (Examples 10 to 12) to the curved surface 20 of the light-transmitting plate 21.

In Examples 10 to 12, a "light-controlling cell 22 having the same characteristics" was attached to a "light-transmitting plate 21 having the same characteristics" via an "optically transparent adhesive film 24 having different characteristics", and the state of the light-controlling cell 22 attached to the light-transmitting plate 21 was evaluated. Specifically, a light-transmitting plate 21 and a light-controlling cell 22 having the same characteristics as those in Example 8 (FIG. 13) were used, while an optically transparent adhesive film 24 having a different thickness in the stacking direction, a different storage modulus at room temperature, and a different loss tangent was used. These physical properties of Examples 10 to 12 shown in FIG. 14 were measured using a UBM Corporation (UBM) property measuring device "Rheogel E4000" with a vibration frequency set to 10 Hz (Hertz) and a temperature rise condition set to 5°C/min (minute). FIG. 14 shows the storage modulus and loss tangent at 25°C and 50°C, respectively.

In the "Adhesive state of the dimming cell" section of FIG. 14, "Average" (Example 10) indicates that the dimming cell 22 is slightly distorted. "Good" (Example 11) indicates that the dimming cell 22 is in a relatively good state, although it has a smaller distortion than the dimming cell 22 in Example 10. "Excellent" (Example 12) indicates that the dimming cell 22 is in a very good state, with no distortion at all.

When Examples 10 to 12 are compared, it is found that from the viewpoint of improving the bonding state of the dimming cell 22 to the light-transmitting plate 21, the smaller the storage modulus of the optically transparent adhesive film 24 is, the better (see, for example, Example 10 ("2.9 x 10 ⁷ Pa/25°C") and Example 11 ("1.1 x 10 ⁷ Pa/25°C")). Furthermore, it is found that the smaller the loss tangent of the optically transparent adhesive film 24 is, the better (see, for example, Example 10 ("0.95/25°C"), Example 11 ("0.90/25°C") and Example 12 ("0.41/25°C"). It is also considered that the thickness of the optically transparent adhesive film 24 in the lamination direction is preferably thicker, but when Examples 10 to 12 are compared, it is considered that the storage modulus and loss tangent of the optically transparent adhesive film 24 have a greater effect on the bonding state of the dimming cell 22 to the light-transmitting plate 21 than the thickness of the optically transparent adhesive film 24.

<Detailed structure of spacer>
A preferred example of the relationship between the "hardness of the spacer 52" and the "hardness of the portion with which the tip of the spacer 52 abuts" will be described below.

In the embodiment described below, the spacer 52 is formed in a cylindrical or truncated cone shape using photoresist in the manufacturing process of the dimming cell 22 shown in FIG. 15. That is, in the manufacturing process of the dimming cell 22, the manufacturing of the first laminate (see reference number "SP1" in FIG. 15), the manufacturing of the second laminate (see reference number "SP2" in FIG. 15), the manufacturing of the liquid crystal cell (see "liquid crystal layer 49" in FIG. 3) (see reference number "SP3" in FIG. 15), and the lamination of these members (see reference number "SP4" in FIG. 15) are carried out in sequence. The manufacturing process SP1 of the first laminate includes the manufacturing process SP1-1 of the electrode (i.e., the "second electrode layer 32"), the manufacturing process SP1-2 of the spacer 52, and the manufacturing process SP1-3 of the alignment layer (i.e., the "second alignment film 34"). Although not shown in the figure, the manufacturing process SP2 of the second laminate includes a manufacturing process of the electrode (i.e., the first electrode layer 31) and a manufacturing process of the alignment layer (i.e., the "first alignment film 33"). In this manner, the spacers 52 are manufactured, and in this embodiment, the Vickers hardness value Xs of each spacer 52 is set to 16.9 or more and 40.2 or less (i.e., "16.9≦Xs≦40.2" is satisfied), and the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abuts is set to 11.8 or more and 35.9 or less (i.e., "11.8≦Xf≦35.9" is satisfied), thereby further improving the reliability of the spacer compared to the conventional case. The Vickers hardness value is a measured value under the conditions described in the following examples.

For example, when no covering portion is provided and each spacer 52 is mainly composed of only the core portion (i.e., when the spacer 52 includes a core portion but not a covering portion), the above Xs is represented by the Vickers hardness value of each of the multiple spacers (core portions) 52, and the above Xf is represented by the Vickers hardness value of the portion of the first alignment film 33 with which the tip of each of the multiple spacers 52 abuts. On the other hand, when a covering portion is provided on the core portion and each spacer 52 is mainly composed of a combination of the core portion and the covering portion (i.e., when the spacer 52 includes a core portion and a covering portion), the above Xs is represented by the Vickers hardness value of the core portion and the covering portion of each spacer 52, and the above Xf is represented by the Vickers hardness value of the portion of the first alignment film 33 with which the covering portion covering the tip of each of the multiple spacers 52 abuts. Here, "the Vickers hardness value of the core portion and coating portion of each spacer 52" refers to the Vickers hardness value measured when the core portion is coated with the coating portion.

If the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abuts is less than 11.8, the pressing force during use will cause the tip of the spacer 52 to penetrate into the opposing surface, resulting in uneven cell gaps and local alignment defects. In this case, scratches will occur in the first resin base material 29 due to contact during assembly of the spacer 52, and cracks will occur when the entire assembly is bent.

Furthermore, if the Vickers hardness value Xs of the spacer 52 is less than 16.9, the spacer 52 will be crushed by external pressure, reducing the cell gap and making it impossible to obtain the desired cell gap. Also, if the Vickers hardness value Xs of the spacer 52 exceeds 40.2, or if the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abuts exceeds 35.9, the cell gap may be reduced and scratches or cracks may occur.

However, if the Vickers hardness value Xs of the spacer 52 is set to 16.9 or more and 40.2 or less, and the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abuts is set to 11.8 or more and 35.9 or less, these problems can be solved at once, and the reliability of the spacer 52 can be further improved compared to the conventional case.

[Test results]
16 and 17 are charts showing the test results used to confirm the configuration of the spacer. The examples in FIG. 16 and FIG. 17 are configured identically, except that the configurations of the spacer 52 and the alignment layer with which the spacer 52 abuts are different. More specifically, the light control cells of these examples are provided with the spacer 52 only in the lower laminate (see the second electrode alignment layer 44), and the Vickers hardness value Xs of the spacer 52 is changed by adjusting the manufacturing conditions for the spacer 52. In addition, the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) with which the tip of the spacer 52 abuts is changed by adjusting the conditions for manufacturing the first alignment film 33.

That is, the spacers 52 are formed by applying a coating liquid for the spacers 52, drying the coating liquid, and then selectively exposing the areas where the spacers 52 are to be manufactured by mask exposure using an exposure device. Note that this is the case for negative photoresist; conversely, with positive photoresist, the areas other than the areas where the spacers 52 are to be disposed are selectively exposed to light. Thereafter, the unexposed areas or the exposed areas of the spacers 52 are selectively removed by development, and processing such as rinsing is performed, and processing such as drying is performed as necessary.

In this exposure process, the exposure process may be performed on photoresist that has been heated in advance and is in a so-called half-cured state, or in a heated environment. In the development process, a heating process may be performed after a rinse or other process to promote the reaction. The hardness value Xs of the spacer 52 can be determined according to the selection of the photoresist material for the spacer 52, the heating temperatures in the coating process, exposure process, and oven baking, the heating temperature and time settings in the development process, the amount of exposure light and exposure time, and the settings of the mask cap.

In this embodiment, the lower laminate (see second electrode alignment layer 44) was manufactured with a Vickers hardness value Xs of 14.8, 16.9, 22.2, 40.2, or 51.4 for the spacer 52 by adjusting the heating temperature and time in the exposure and development steps (FIG. 18). Note that this hardness is a measurement value obtained by adjusting the manufacturing conditions of the spacer 52 to manufacture the lower laminate (see second electrode alignment layer 44), manufacturing the dimming cell 22 using this lower laminate (see second electrode alignment layer 44), disassembling it, and measuring it. In addition, this measurement value is the measurement result of measuring 12 points for each dimming cell, excluding the maximum and minimum values, and averaging the remaining 10 points.

The spacers 52 were manufactured in a cylindrical shape with a diameter of 9 μm and a height of 6 μm. The spacers 52 were regularly arranged at a pitch of 110 μm in two directions perpendicular to each other in the in-plane direction of the second resin base material 30. Therefore, the proportion (occupancy rate) of the spacers 52 on the second resin base material 30 was 0.5% (=((9/2) ² ×3)/(110) ² ).

Increasing the occupancy rate of the spacers 52 reduces the stress applied to each spacer, reducing the risk of the spacers 52 being crushed or their tips penetrating, but this leads to a deterioration in transmittance and light blocking rate. However, when the occupancy rate of the spacers 52 is small, the optical properties such as the transmittance and light blocking rate can be ensured, but it becomes impossible to avoid the phenomenon of the spacers 52 being crushed or their tips penetrating. For this reason, it is desirable for the occupancy rate of the spacers 52 to be 0.5% or more and 10% or less.

On the other hand, the first alignment film 33 of the first electrode alignment layer 43, which is the surface that the spacer 52 abuts against, is manufactured by applying a coating liquid, drying and heat curing, and the Vickers hardness value Xf is set to a desired value by adjusting the conditions of this heat curing (heating temperature and heating time), etc. As a result, in the embodiment, the first electrode alignment layer 43 with a Vickers hardness value Xf of 10.2, 11.8, 24.8, 35.9, or 38.5 was manufactured (FIG. 19). Note that this hardness value Xf is a measurement value obtained by manufacturing a first electrode alignment layer 43 with different hardness for the first alignment film 33 of the first electrode alignment layer 43, which is the surface that the spacer 52 abuts against, by adjusting the manufacturing conditions of the first alignment film 33, and then disassembling and measuring the dimming cell 22 once using this first electrode alignment layer 43. In addition, this measurement value is the measurement result of measuring at 12 points, excluding the maximum and minimum values, and averaging the remaining 10 points.

The Vickers hardness values Xs and Xf were measured using a PICODENTOR HM500 manufactured by Helmut Fischer. The measurement conditions were a pressing speed of 300 mN/20 sec, a release speed of 300 mN/20 sec, a creep time of 5 sec, and a maximum load of 100 mN.

In each embodiment of FIG. 16 and FIG. 17, a dimming cell was manufactured and tested using the first electrode alignment layer 43 and the second electrode alignment layer 44 manufactured in this manner. In the tests of FIG. 16 and FIG. 17, a load equivalent to 0.8 MPa was applied while the dimming cell was placed on a smooth surface having a high hardness made by a surface plate, and the cell gap was measured to determine the reduction in the cell gap. The load was applied for 24 hours. After the load was applied in this manner, the upper laminate including the first alignment film 33 and the lower laminate including the second alignment film 34 were peeled off, and the spacer 52 was observed under a microscope to observe the crushing of the spacer 52 (hereinafter also referred to as "spacer crushing") and the reduction in the cell gap were observed, and the portion where the spacer 52 abutted was observed under a microscope to observe the state of penetration (film penetration) of the tip of the spacer 52.

In this observation using a microscope, a front view, an oblique view, and a cross section were observed using a method such as SEM, and the presence or absence of deformation of the spacer 52 was visually confirmed. If deformation of the spacer 52 was confirmed, the presence or absence of "cell gap reduction, spacer crushing" was judged as ○ or △ depending on the situation. Therefore, in Figures 16 and 17, "○" indicates a case where no abnormality was found in the corresponding item, and "△" indicates a case where an abnormality was found in the corresponding item.

Similarly, the area where the spacer 52 abuts was viewed obliquely using a method such as SEM, and if a depression (concave) was confirmed, the "film penetration" was rated as "△", and if no concave was observed, the "film penetration" was rated as "○".

In addition, the first electrode orientation layer 43 and the second electrode orientation layer 44 were stacked and a load equivalent to 0.1 MPa was applied, and the relative positions of the first electrode orientation layer 43 and the second electrode orientation layer 44 were displaced at 0.1 cm/sec, and the occurrence of scratches was confirmed visually. Here, if the occurrence of scratches was confirmed in more than half of the multiple samples, the "Scratches" item in Figures 16 and 17 is indicated by "△", and conversely, if the occurrence of scratches was not confirmed in more than half of the multiple samples, the "Scratches" item is indicated by "○".

In addition, in the state of the dimming cell, the dimming cell was wrapped around a cylindrical mandrel with a diameter of 2 mm in accordance with the bending test provisions of JIS K5600-5-1, and the presence or absence of cracks in the substrate (occurrence of cracks in the first resin substrate 29 and the second resin substrate 3) was confirmed. In this test, if cracks were confirmed in the substrate in more than half of the multiple samples, the "Crack" item in Figures 16 and 17 is indicated with a "△", and conversely, if cracks were not confirmed in the substrate in more than half of the multiple samples, the "Crack" item is indicated with a "○".

16 and 17, when the Vickers hardness value Xs of the spacer 52 is less than 16.9 (Examples 30 and 32), a decrease in the cell gap is observed, and in Example 30, the tip of the spacer penetrates the film, and scratches and cracks are observed. When the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abuts is less than 11.8 (Examples 20 and 22), scratches and cracks are observed, and in Example 22, the tip of the spacer penetrates the film.

Furthermore, when the Vickers hardness value Xs of the spacer 52 exceeded 40.2 (Examples 31 and 33), a decrease in the cell gap and penetration of the tip of the spacer into the film were observed in Example 31, and scratches were observed in Example 33. Furthermore, when the Vickers hardness value Xf of the portion of the first electrode alignment layer 43 (particularly the first alignment film 33) where the tip of the spacer 52 abutted exceeded 35.9 (Examples 21 and 23), a decrease in the cell gap and scratches were observed, and furthermore, cracks were observed in Example 23.

However, in Examples 13 to 19 and 24 to 29, these phenomena (the "cell gap reduction," "film penetration," "scratches," and "cracks" shown in Figures 16 and 17) were not observed, confirming that the reliability of the spacer 52 can be sufficiently ensured.

<Guest Host LCD>
The present invention is also applicable to a light control cell 22 that uses a guest-host type liquid crystal. That is, the liquid crystal layer 49 may contain a dichroic dye (guest) and liquid crystal (host). The dichroic dye contained in the liquid crystal layer 49 is preferably a coloring material that has a light-shielding property and can block (absorb) desired visible light.

The specific configuration of the light control cell 22 using guest-host type liquid crystal to which the present invention can be applied is not particularly limited. For example, instead of providing a pair of polarizing plates (see the first polarizing plate 41 and the second polarizing plate 42 in FIG. 3), only one polarizing plate may be provided as shown in FIGS. 20 and 21 described below, or no polarizing plate may be provided as shown in FIGS. 22 and 23 described below. A typical example of a light control cell 22 using guest-host type liquid crystal is described below.

Figure 20 is a conceptual diagram for explaining an example of a dimming cell 22 using a guest-host type liquid crystal (light blocking state), where FIG. 20(a) is a cross-sectional view of the dimming cell 22, and FIG. 20(b) is a plan view of the first polarizing plate 41 with the absorption axis direction indicated by the arrow "A". Figure 21 is a conceptual diagram for explaining the same dimming cell 22 (light transmitting state) as FIG. 20, where FIG. 21(a) is a cross-sectional view of the dimming cell 22, and FIG. 21(b) is a plan view of the first polarizing plate 41 with the absorption axis direction indicated by the arrow "A". Note that the absorption axis and polarization axis (light transmitting axis) of the first polarizing plate 41 extend in directions perpendicular to each other.

The dimming cell 22 shown in FIG. 20 and FIG. 21, like the dimming cell 22 shown in FIG. 3, includes a pair of film substrates (i.e., the first resin substrate 29 and the second resin substrate 30), a pair of transparent electrodes (i.e., the first electrode layer 31 and the second electrode layer 32) disposed between the pair of film substrates, a pair of alignment films (i.e., the first alignment film 33 and the second alignment film 34) disposed between the pair of transparent electrodes, and a liquid crystal layer 49 and a spacer 52 disposed between the pair of alignment films. However, in the dimming cell 22 shown in FIG. 20 and FIG. 21, only one polarizing plate (the first polarizing plate 41 in this example) is provided on the opposite side of the pair of transparent electrodes via one of the pair of film substrates (the first resin substrate 29 in this example). The first polarizing plate 41 is attached to the first resin substrate 29 via an adhesive layer 46. The liquid crystal layer 49 is composed of a guest-host type liquid crystal containing a dichroic dye (dye) 61 and liquid crystal 62.

The dichroic dye 61 exists in a dispersed state in the liquid crystal 62, has the same orientation as the liquid crystal 62, and is basically aligned in the same direction as the liquid crystal 62.

In this example, when the voltage between a pair of transparent electrodes (the first electrode layer 31 and the second electrode layer 32) is OFF, the dichroic dye 61 and the liquid crystal 62 are aligned in a horizontal direction perpendicular to the light traveling direction L (i.e., the stacking direction of the dimming cell 22) (particularly, in a direction perpendicular to the absorption axis direction A of the first polarizer 41 (i.e., the same direction as the polarization axis of the first polarizer 41)) (see FIG. 20(a)). On the other hand, when the voltage between a pair of transparent electrodes (the first electrode layer 31 and the second electrode layer 32) is ON, the dichroic dye 61 and the liquid crystal 62 are aligned in a vertical direction (i.e., the light traveling direction L) (see FIG. 21(a)). Note that in FIG. 20(a) and FIG. 21(a), the dichroic dye 61 and the liquid crystal 62 are conceptually illustrated to show the orientation direction of the dichroic dye 61 and the liquid crystal 62.

For example, when no voltage is applied to the first electrode layer 31 and the second electrode layer 32 by a dimming controller (not shown), the desired electric field is not applied to the liquid crystal layer 49, and the dichroic dye 61 and the liquid crystal 62 are aligned horizontally (see FIG. 20(a)). In this case, light vibrating in a direction perpendicular to the absorption axis direction A of the first polarizer 41 is blocked by the dichroic dye 61, and light vibrating in other directions is blocked by the first polarizer 41. Therefore, light traveling in a direction from the second film substrate 24 toward the first polarizer 41 (see arrow "L") is blocked by the dichroic dye 61 and the first polarizer 41.

On the other hand, when a voltage is applied to the first electrode layer 31 and the second electrode layer 32 by a dimming controller (not shown), a desired electric field is applied to the liquid crystal layer 49, and the dichroic dye 61 and the liquid crystal 62 are aligned vertically (see FIG. 21(a)). In this case, the light blocking performance of the dichroic dye 61 against the light passing through the liquid crystal layer 49 is not exerted very much regardless of the vibration direction of the light, and the light that enters the liquid crystal layer 49 passes through the liquid crystal layer 49 (the dichroic dye 61 and the liquid crystal 62) with a high probability. In addition, the light vibrating parallel to the polarization axis (light transmission axis) of the first polarizer 41 (in this example, the light vibrating in a direction perpendicular to the absorption axis direction A of the first polarizer 41) passes through the first polarizer 41 and is emitted from the dimming cell 22.

Even when using the guest-host type liquid crystal layer 49 shown in Figures 20 and 21 as described above, the translucency of the dimming cell 22 can be appropriately changed by controlling the voltage applied to the first electrode layer 31 and the second electrode layer 32.

20 and 21, the above description has been given of the case where the so-called normally black type alignment films 33, 34 and liquid crystal layer 49 are used, but the so-called normally white type alignment films 33, 34 and liquid crystal layer 49 may also be used. That is, in the case of normally black, as described above, when a voltage is applied between the electrodes 25 and 26 to apply an electric field to the liquid crystal layer 49, it is necessary to align the dichroic dye 61 and the liquid crystal 62 in the vertical direction, so horizontal alignment films are used as the alignment films 33 and 34, and positive liquid crystal is used for the liquid crystal layer 49. On the other hand, in the case of normally white, when a voltage is applied between the electrodes 25 and 26 to apply an electric field to the liquid crystal layer 49, it is necessary to align the dichroic dye 61 and the liquid crystal 62 in the horizontal direction as shown in FIG. 20(a), so vertical alignment films are used as the alignment films 33 and 34, and negative liquid crystal is used for the liquid crystal layer 49.

Figure 22 is a conceptual diagram for explaining another example of a dimming cell 22 using a guest-host type liquid crystal (light-shielding state), and shows a cross section of the dimming cell 22. Figure 23 is a conceptual diagram for explaining the same dimming cell 22 (light-transmitting state) as Figure 22, and shows a cross section of the dimming cell 22.

The dimming cell 22 of this example has a basically similar configuration to the dimming cell 22 shown in Figures 20 and 21, but does not have polarizing plates (first polarizing plate 41 and second polarizing plate 42), and is a guest-host type in which the liquid crystal layer 49 contains a dichroic pigment (dye) 51 and liquid crystal 62. In other words, the dichroic pigment 61 exists in a dispersed state in the liquid crystal 62, has the same orientation as the liquid crystal 62, and is basically aligned in the same direction as the liquid crystal 62.

In this example, when the voltage between the pair of transparent electrodes (the first electrode layer 31 and the second electrode layer 32) is OFF, the dichroic dye 61 and the liquid crystal 62 are aligned in the horizontal direction (i.e., perpendicular to the light traveling direction L) (see FIG. 22). In particular, the orientation of the dichroic dye 61 and the liquid crystal 62 in this example is preferably twisted by 180 degrees or more with respect to the horizontal direction when no electric field is applied, so that the dichroic dye 61 is oriented in any horizontal direction. On the other hand, when the voltage between the pair of transparent electrodes (the first electrode layer 31 and the second electrode layer 32) is ON, the dichroic dye 61 and the liquid crystal 62 are aligned in the vertical direction (i.e., the light traveling direction L) (see FIG. 23). In FIG. 22 and FIG. 23, the dichroic dye 61 and the liquid crystal 62 are conceptually illustrated to show the orientation direction of the dichroic dye 61 and the liquid crystal 62.

For example, when no voltage is applied to the first electrode layer 31 and the second electrode layer 32 by a dimming controller (not shown), the desired electric field is not applied to the liquid crystal layer 49, and the dichroic dye 61 and the liquid crystal 62 are aligned horizontally (see FIG. 22). As a result, the light that enters the liquid crystal layer 49 is blocked (absorbed) by the dichroic dye 61.

On the other hand, when a voltage is applied to the first electrode layer 31 and the second electrode layer 32 by a dimming controller (not shown), a desired electric field is applied to the liquid crystal layer 49, and the dichroic dye 61 and the liquid crystal 62 are aligned vertically (see FIG. 23). In this case, the light blocking performance of the dichroic dye 61 against the light passing through the liquid crystal layer 49 is not exerted very much regardless of the vibration direction of the light, and the light that enters the liquid crystal layer 49 passes through the liquid crystal layer 49 (the dichroic dye 61 and the liquid crystal 62) with a high probability. In addition, since a polarizing plate is not provided in this example, all of the light that passes through the liquid crystal layer 49 and exits from the first film substrate 23 is exited from the dimming cell 22.

As described above, even when using the guest-host type liquid crystal layer 49 shown in Figures 22 and 23, the translucency of the dimming cell 22 can be changed by controlling the voltage applied to the first electrode layer 31 and the second electrode layer 32.

With regard to the dimming cell 22 shown in Figures 22 and 23, the above description is of a normally black guest-host type dimming cell 22 using horizontal alignment films as the alignment films 33, 34 and positive liquid crystal for the liquid crystal layer 49, but a normally white guest-host type dimming cell 22 may also be used. That is, a vertical alignment film may be used as the alignment films 33, 34 and negative liquid crystal may be used for the liquid crystal layer 49, and when a voltage is applied between the electrodes 25, 26 to apply an electric field to the liquid crystal layer 49, the dichroic dye 61 and the liquid crystal 62 may be aligned in the horizontal direction as shown in Figure 22.

Note that the hard coat layer 26 shown in FIG. 3 is not shown in the above-mentioned FIGS. 20 to 23, but the hard coat layer 26 may or may not be provided in each of the dimming cells 22 shown in FIGS. 20 to 23. When the hard coat layer 26 is provided, the hard coat layer 26 may be attached to the second resin base material 30 via an adhesive layer 46, for example. In addition, the retardation compensation film 45 shown in FIG. 3 is not shown in the above-mentioned FIGS. 20 to 23, but the retardation compensation film 45 may or may not be provided in each of the dimming cells 22 shown in FIGS. 20 to 23. When the retardation compensation film 45 is provided, the retardation compensation film 45 may be attached to the second resin base material 30 via an adhesive layer 46, for example.

Even when using a dimming cell 22 having the above-mentioned guest-host type liquid crystal (i.e., a liquid crystal layer 49 containing a dichroic dye 61), an optically transparent adhesive film 24 can be disposed between the curved surface 20 of the light-transmitting plate 21 and the dimming cell 22, and one side of the dimming cell 22 can be adhered to the curved surface 20 of the light-transmitting plate 21.

<E-type linear polarizing plate>
The present invention is also applicable to a dimming cell 22 equipped with an E-type linear polarizer. A VA-type dimming cell will be described below as an example, but the driving method of the dimming cell is not particularly limited, and the technology described below can be applied to, for example, a TN-type, IPS-type, or FFS-type dimming cell. In other words, the liquid crystal layer may be a VA-type, TN-type, IPS-type, or FFS-type liquid crystal layer.

[First mode]
[Basic configuration]
24 is a cross-sectional view for explaining the basic structure of the light control cell according to the present invention. The light control cell 22 is a light control film by the VA method, and is configured by sandwiching a liquid crystal layer 114 and a spacer 115 between a lower laminate 112 and an upper laminate 113, which are first and second laminates in the form of films. The lower laminate 112 is provided with a linear polarizer 112D on a substrate 112B made of a transparent film material having a hard coat layer 112A and a hard coat layer 112C. Furthermore, a negative C plate layer 112F, a transparent electrode 112G, and an alignment film 112E, which are provided for optical compensation, are sequentially provided on the linear polarizer 112D. The outer hard coat layer 112A is configured, for example, by a laminate structure of two hard coat layers.

The upper laminate 113 is provided with a transparent electrode 113D on a substrate 113B made of a transparent film material having a hard coat layer 113A and a hard coat layer 113C, and further provided with a linear polarizer 113E. In the upper laminate 113, an alignment film 113F is provided on the liquid crystal layer 114 side of the linear polarizer 113E.

Here, the hard coat layers 112A and 112C are made to have a thickness of about 10 μm and 5 μm. The hard coat layers 113A and 113C are made to have a thickness of about 5 μm and 5 μm. The substrates 112B and 113B are made of a versatile film material with high optical anisotropy, for example a PET film with a thickness of 100 μm. The transparent electrodes 112G and 113D are made of ITO with a thickness of 50 nm.

Linear polarizers 112D and 113E are optical functional layers that function as E-type linear polarizers. Here, an E-type linear polarizer is a linear polarizer that has a polarizing layer formed by the orientation of dye molecules, as described in JP 2011-59266 A and JP 8-511109 A. The polarizing layer of linear polarizers 112D and 113E has an absorption axis perpendicular to the alignment direction of the dye molecules, and is a polarizing layer in which the extraordinary refractive index is smaller than the ordinary refractive index and the transmittance of the extraordinary wave is greater than that of the ordinary wave.

The E-type polarizing layer can be produced by applying a coating liquid containing dye molecules related to the polarizing layer to produce a coating film, and then applying mechanical stress (shear force) to this coating layer to orient the dye molecules. Various production methods can be applied, such as applying stress while applying the coating liquid. As a result, in this mode, the overall thickness can be made thin, and it is configured so that various highly versatile film materials can be used for the substrates 112B and 113B.

That is, in a conventional light control cell, it is necessary to use a transparent film material with small optical anisotropy so that the transmitted light of the liquid crystal layer incident on the linear polarizer does not lose the polarization plane controlled by the liquid crystal layer, which makes it difficult to use a highly versatile film material. However, in this mode, when the linear polarizers 112D and 113E are provided on the liquid crystal layer 114 side of the substrates 112B and 113B, even if the transmitted light is polarized in various ways by the substrates 112B and 113B, it is possible to prevent any effect on the polarization plane of the transmitted light of the liquid crystal layer 114. This makes it possible to apply a film material with large optical anisotropy, such as a PET film, to the substrates 112B and 113B, which makes it possible to use a highly versatile transparent film material.

In addition, by using linear polarizers 112D and 113E, which are E-type linear polarizers, it is possible to sufficiently block transmitted light in oblique directions, which makes it possible to reduce the overall thickness without providing a compensation film.

In addition, the linear polarizers 112D and 113E associated with such E-type linear polarizers can be provided on the inside of the liquid crystal cell by a coating film, and thus provided on the liquid crystal layer 114 side of the substrates 112B and 113B, simplifying the configuration associated with the linear polarizers and making them even thinner. In practice, when the linear polarizers 112D and 113E are arranged as shown in FIG. 24, the thickness of the linear polarizers 112D and 113E associated with the E-type linear polarizers is about 1 μm, so that the thickness of the entire dimming cell 22 can be about 300 μm, which is significantly thinner than in the past.

[Specific Configuration of First Mode]
25 is a cross-sectional view showing a specific configuration of a light control cell 22 according to the first mode of the present invention. The light control cell 22 is formed in a film shape. The light control cell 22 is a VA type light control film that uses liquid crystal to control transmitted light, and is formed by sandwiching a liquid crystal layer 124 between a lower laminate 122 and an upper laminate 123, which are first and second laminates each in a film shape. Here, the light control cell 22 is a liquid crystal cell that controls the orientation of liquid crystal molecules in the liquid crystal layer 124 by the VA type.

That is, in the dimming cell 22, the lower laminate 122 has a transparent electrode 122B, which is a first electrode, formed on the entire surface of a substrate 122A made of a transparent film material with hard coat layers on both sides. Here, for example, a PET film is applied to this substrate 122A. Also, for example, ITO is applied to the transparent electrode 122B. Furthermore, the lower laminate 122 has an E-type linear polarizer 122C, a negative C plate layer 122D, and an alignment film 122E formed in that order.

The upper laminate 123 is made by sequentially fabricating a transparent electrode 123B, a linear polarizer 123C, and an alignment film 123D on a substrate 123A made of a transparent film material with hard coat layers on both sides. The linear polarizers 122C and 123C are arranged in a crossed Nicol configuration.

Here, ITO is applied to the transparent electrodes 122B and 123B. E-type linear polarizers are applied to the linear polarizers 122C and 123C, and more specifically, the configuration disclosed in JP-A-8-511109 can be applied, and the linear polarizers 122C and 123C are formed by a coating film of a dichroic organic dye that exhibits optical anisotropy in the vertical direction. The negative C plate layer 122D is a negative uniaxial retardation optical layer in which the refractive index distribution satisfies nz < nx = ny, where nx is the main refractive index in the plane (slow axis direction), ny is the refractive index in the fast axis direction, and nz is the refractive index in the thickness direction. The negative C plate layer 122D can be made of, for example, a TAC (triacetyl cellulose) film material, but in this mode, it is made of a cholesteric polymerizable liquid crystal layer made of an ultraviolet curable resin. Although photo-alignment films are used for the alignment films 122E and 123D, various configurations can be used, such as alignment films made by rubbing treatment, alignment films made by molding treatment to create fine line-shaped uneven shapes, etc.

The dimming cell 22 has a columnar spacer 125 that maintains the thickness of the liquid crystal layer 124, which is fabricated on the alignment film 122E of the lower laminate 122. However, it may be provided on the negative C plate layer 122D, or on the linear polarizer 122C or transparent electrode 122B. It may also be provided on the upper laminate 123 side, or on both the lower laminate 122 and the upper laminate 123.

In addition, the dimming cell 22 has a sealant arranged in a frame shape surrounding the liquid crystal layer 124, and this sealant prevents leakage of liquid crystal from the liquid crystal layer 124 and also holds the upper laminate 123 and the lower laminate 122 together. Here, the sealant can be made of various materials that can prevent leakage of liquid crystal and hold the upper laminate 123 and the lower laminate 122 together, but in this mode, for example, a thermosetting resin made of epoxy resin, an ultraviolet-curing resin made of acrylic resin, or a curing resin that hardens with heat and ultraviolet light is used.

As a result, in the dimming cell 22 of FIG. 25, by applying an E-type linear polarizer to the linear polarizers 122C and 123C and providing the linear polarizers 122C and 123C on the liquid crystal layer 124 side of the lower laminate 122 and the upper laminate 123, it is possible to apply a highly versatile material to the base materials 122A and 123A of the lower laminate 122 and the upper laminate 123. In addition, by applying an E-type linear polarizer to the linear polarizers 122C and 123C, the overall thickness can be reduced.

Figure 26 is a flow chart explaining the manufacturing process of the dimming cell 22. In the manufacturing process of the dimming cell, the upper laminate 123 and the lower laminate 122 are manufactured in the upper laminate manufacturing process SP102 and the lower laminate manufacturing process SP103, respectively. In the lamination process SP104, the upper laminate 123 and the lower laminate 122 are laminated with the liquid crystal layer 124 sandwiched therebetween, and then the dimming cell 22 is manufactured by integrating them with a sealant.

Figure 27 is a flowchart showing the upper laminate manufacturing process SP102 in detail. In this upper laminate manufacturing process SP102 (SP111), in the transparent electrode manufacturing process SP112, a transparent electrode 123B is manufactured by ITO by sputtering or the like, and in the subsequent linear polarizer manufacturing process SP113, the coating liquid of the linear polarizer 123C is applied to the substrate 123A on which the transparent electrode 123B is manufactured, and then dried, thereby manufacturing the linear polarizer 123C. In addition, in the linear polarizer manufacturing process, when applying the coating liquid or after manufacturing the coating film, the coating film is stretched with a blade or the like to apply a shear force to the coating film, and the dye related to the linear polarizer 123C is oriented in the stretched direction, thereby manufacturing the linear polarizer 123C so that it functions as a linear polarizer. Next in this manufacturing process, in the alignment film creation step SP114, a coating liquid for alignment film 123D is applied and dried, and then cured by irradiation with linearly polarized ultraviolet light to create alignment film 123D.

Figure 28 is a flow chart showing the lower laminate manufacturing process SP103 in detail. In this lower laminate manufacturing process SP103 (SP121), in the electrode manufacturing process SP122, a transparent electrode 122B is manufactured by sputtering on the entire surface of the substrate 122A using ITO. Next, in the linear polarizer manufacturing process SP123, the linear polarizer 122C coating liquid is applied and then dried in the same manner as in the linear polarizer manufacturing process SP112, thereby manufacturing the linear polarizer 122C. Next, in the C plate layer manufacturing process SP124, the alignment film coating liquid for the negative C plate layer 122D is applied and then dried, and an alignment control force is set by irradiation with ultraviolet light or the like to manufacture an alignment film. In addition, a coating liquid for cholesteric liquid crystal is applied on this alignment film, dried, and then cured by irradiation with ultraviolet light, thereby manufacturing the negative C plate layer 122D.

Then, in the subsequent alignment film preparation process SP125, the alignment film 122E is formed by applying a coating liquid for the alignment film 122E, drying it, and exposing it to light. Then, in the subsequent spacer preparation process SP126, the spacer 125 is prepared by applying a photoresist material to the entire surface, drying it, exposing it, and developing it. Note that a transparent film material such as TAC may be applied to the negative C plate layer 122D, and the alignment film 122E, etc. may be prepared in advance on this transparent film material and laminated to the substrate 122A side.

[Second mode]
29 is a cross-sectional view showing a dimming cell according to the second mode of the present invention. This dimming cell 22 is configured in the same manner as the dimming cell 22 according to the first mode, except that the transparent electrode 122B is disposed between the alignment film 122E and the negative C plate layer 122D to form the lower laminate 132.

In this mode, even if the transparent electrode 122B is disposed between the alignment film 122E and the negative C plate layer 122D to form the lower laminate, the same effect as the dimming cell 22 in the first mode can be obtained.

[Third Mode]
30 is a cross-sectional view showing a light control cell according to the third mode of the present invention. In this light control cell 22, a laminate for the negative C plate layer 122D is produced by producing a transparent electrode 122B and an alignment film 122E on a transparent film material such as TAC for the negative C plate layer 122D, and the laminate for the negative C plate layer is laminated on a substrate 122A formed of a linear polarizer 122C with an adhesive layer 142A to produce a lower laminate 142. Note that after laminating the substrate 122A formed of a linear polarizer 122C on a transparent film material for the negative C plate layer 122D, the transparent electrode 122B and the alignment film 122E may be produced, or only the transparent electrode 122B may be produced on the transparent film material for the negative C plate layer 122D. In this mode, the light control cell is configured in the same manner as the light control cell according to the above-mentioned mode, except that the configuration of the lower laminate 142 is different.

In this mode, even if the laminate relating to the negative C plate layer 122D is laminated with an adhesive layer to create a lower laminate, it is possible to obtain the same effect as the dimming cell relating to the first or second mode.

[Fourth mode]
31 is a cross-sectional view showing a light control cell according to the fourth mode of the present invention. In this light control cell 22, a transparent film material for a negative C plate layer 122D formed by preparing an alignment film 122E and a spacer 125 is laminated on a substrate 122A formed by sequentially preparing a transparent electrode 122B and a linear polarizer 122C, with an adhesive layer 142A to prepare a lower laminate 152. The alignment film 122E and/or the spacer 125 may be prepared after lamination with the substrate 122A. In this mode, the light control cell is configured in the same manner as the light control cell according to the above-mentioned mode, except that the order of preparation of each of these parts is different.

According to this mode, the same effect as the above-mentioned mode can be obtained by laminating a laminate of a negative C plate layer 122D, which is made of an alignment film 122E and a spacer 125, to a substrate 122A, which is made of a transparent electrode 122B and a linear polarizer 122C, with an adhesive layer 142A to produce a lower laminate 152. In this case, the laminate of the substrate, transparent electrode, and linear polarizer can have the same configuration for the upper laminate and the lower laminate, which can simplify the manufacturing process.

[Fifth mode]
32 is a cross-sectional view showing a dimming cell according to the fifth mode of the present invention. The dimming cell 22 is configured in the same manner as the first mode, except that the negative C plate layer 122D is omitted from the lower laminate 162.

In cases where sufficient optical characteristics for practical use can be ensured, such as in this mode, the negative C-plate layer can be omitted to simplify the configuration, and the same effect as the above-mentioned mode can be obtained.

[Other modes]
Although specific configurations suitable for implementing the present invention have been described in detail above, the present invention allows combinations of the above-mentioned modes and further allows various modifications of the above-mentioned modes without departing from the spirit of the present invention.

For example, in the second mode described above, the lower laminate is constructed by arranging the transparent electrode directly below the alignment film, but the present invention is not limited to this, and the upper laminate may also be similarly constructed by arranging the transparent electrode directly below the alignment film.

In the above mode, a case was described in which a columnar spacer was created using photoresist, but the present invention is not limited to this, and so-called bead spacers may also be used.

Even when using a dimming cell 22 that uses the above-mentioned E-type linear polarizer, an optically transparent adhesive film 24 can be placed between the curved surface 20 of the light-transmitting plate 21 and the dimming cell 22, and one side of the dimming cell 22 can be adhered to the curved surface 20 of the light-transmitting plate 21.

<Structure of light control cell sandwiched between light-transmitting plates>
The present invention is also applicable to the case where the dimming cell 22 is sandwiched between a pair of light-transmitting plates.

Figure 33 is a schematic cross-sectional view showing another example of the dimming device 10. The dimming device 10 shown in Figure 33 is basically configured in the same manner as the dimming device 10 shown in Figure 1. That is, an optically transparent adhesive film 24 is disposed between the curved surface 20 of the first light-transmitting plate 221 containing an ultraviolet blocking component and the dimming cell 22, and one side of the dimming cell 22 is adhered to the curved surface 20 of the first light-transmitting plate 221 by the optically transparent adhesive film 24. In this way, the first light-transmitting plate 221 is configured in the same manner as the light-transmitting plate 21 shown in Figure 1.

However, the dimming device 10 shown in FIG. 33 further has a second light-transmitting plate 222, and the dimming cell 22 is disposed between the first light-transmitting plate 221 and the second light-transmitting plate 222. The second light-transmitting plate 222 is disposed away from the dimming cell 22 in the stacking direction of the first light-transmitting plate 221, the optically transparent adhesive film 24, and the dimming cell 22, and the space between the second light-transmitting plate 222 and the dimming cell 22 is configured as an air gap (air layer). The second light-transmitting plate 222 can be configured in the same manner as the first light-transmitting plate 221, for example, and the surface of the second light-transmitting plate 222 facing the dimming cell 22 can be a curved surface similar to the curved surface 20 of the first light-transmitting plate 221. However, the second light-transmitting plate 222 may have a shape different from that of the first light-transmitting plate 221. For example, the surface of the second light-transmitting plate 222 facing the dimming cell 22 may be a curved surface different from the curved surface 20 of the first light-transmitting plate 221, or may be a flat surface. The components of the second light-transmitting plate 222 may be the same as or different from the components of the first light-transmitting plate 221.

By providing an air gap between the second light-transmitting plate 222 and the dimming cell 22, the dimming device 10 shown in FIG. 33 has excellent heat insulating performance and can prevent the dimming device 10 from overheating.

In the dimming device 10 of FIG. 33, the dimming cell 22 is protected by the first light-transmitting plate 221 and the second light-transmitting plate 222. Therefore, the dimming cell 22 does not need to have the hard coat layer 26 shown in FIG. 3.

Figure 34 is a schematic cross-sectional view showing another example of the dimming device 10. The dimming device 10 shown in Figure 34 is basically configured in the same way as the dimming device 10 shown in Figure 33, but the second light-transmitting plate 222 is attached to the other side of the dimming cell 22 via an adhesive layer 223.

The specific components of the adhesive layer 223 are not particularly limited. For example, the adhesive layer 223 can be made of a thermoplastic resin with excellent adhesive properties, such as PVB (polyvinyl butyral), or other adhesive materials with optical transparency.

In the dimming device 10 of FIG. 34, the dimming cell 22 is protected by the first light-transmitting plate 221 and the second light-transmitting plate 222, so the dimming cell 22 does not need to have a hard coat layer 26.

Figure 35 is a schematic cross-sectional view showing another example of the dimming device 10. The dimming device 10 shown in Figure 35 is basically configured in the same way as the dimming device 10 shown in Figure 33, but the space between the second light-transmitting plate 222 and the dimming cell 22 is sealed and airtight with a sealant 225. In the dimming cell 22 shown in Figure 35, the space between the first light-transmitting plate 221 and the second light-transmitting plate 222 is sealed with a sealant 225, and the optically transparent adhesive film 24 and the dimming cell 22 are arranged in the airtight space.

By disposing a functional member in the sealed space between the second light-transmitting plate 222 and the dimming cell 22, it is possible to add any function to the dimming device 10. For example, by disposing silicone between the second light-transmitting plate 222 and the dimming cell 22 sealed by the sealant 225, it is possible to give the dimming device 10 the functional properties of silicone. It is also possible to dispose other fluids (gases and liquids) or solids (including gels) having optical transparency between the second light-transmitting plate 222 and the dimming cell 22 sealed by the sealant 225. Note that a member containing one or more types of components may be filled in the sealed space between the second light-transmitting plate 222 and the dimming cell 22. Furthermore, the sealed space between the second light-transmitting plate 222 and the dimming cell 22 may be evacuated.

<Other functional layers>
Any functional layer may be added to the light control device 10 according to the above-described embodiment and modified example. For example, an anti-reflection layer may be added to the light control device 10 to improve the optical characteristics.

Figure 36 is a schematic cross-sectional view showing an example of a dimming device 10 equipped with an anti-reflection layer 300. The dimming device 10 shown in Figure 36, like the dimming device 10 shown in Figure 1, is equipped with a light-transmitting plate 21 having a curved surface 20, a dimming cell 22, and an optically transparent adhesive film 24 provided between the light-transmitting plate 21 and the dimming cell 22. However, in the dimming device 10 shown in Figure 36, the anti-reflection layer 300 is provided on the outermost layer of the dimming cell 22.

The specific type and configuration of the anti-reflection layer 300 are not particularly limited, but an optical layer that can adjust the reflection of incident light to exhibit excellent anti-glare properties or suppress outward reflection can be used as the anti-reflection layer 300. Typically, the anti-reflection layer 300 includes at least one of an anti-glare (AG) layer that can reduce regular reflection by diffusing incident light, an anti-reflection (AR) layer that can suppress regular reflection by utilizing the interference of reflected light, and a low-reflection (LR) layer that is made of a low-reflection material with low reflectivity. Therefore, for example, the anti-reflection layer 300 may be made of an AGLR (Anti Glare Low Reflection) layer that is made of a combination of an anti-glare layer and a low-reflection layer. The structure, components, and manufacturing method of the functional layers that make up the anti-reflection layer 300 are not particularly limited, and the anti-reflection layer 300 can be made using any functional layer.

The anti-reflection layer 300 shown in FIG. 36 is provided so as to cover the hard coat layer 26 (see FIG. 3) of the dimming cell 22. However, the hard coat layer 26 and the anti-reflection layer 300 may be realized as a single layer by, for example, mixing fine particles for adjusting reflection into the hard coat layer.

Although not shown, a functional layer such as the anti-reflection layer 300 may be provided in another location of the dimming device 10. For example, in addition to or instead of the anti-reflection layer 300 shown in FIG. 1, a functional layer such as an anti-reflection layer may be provided on the surface of the light-transmitting plate 21. In this way, the anti-reflection layer 300 may be provided on at least one of the dimming cell 22 and the light-transmitting plate 21.

Figure 37 is a schematic cross-sectional view showing another example of a dimming device 10 having anti-reflection layers 300, 301, and 302. The dimming device 10 shown in Figure 37, like the dimming device 10 shown in Figure 33, includes a first light-transmitting plate 221 having a curved surface 20, a second light-transmitting plate 222, a dimming cell 22 provided between the first light-transmitting plate 221 and the second light-transmitting plate 222, and an optically transparent adhesive film 24 provided between the first light-transmitting plate 221 and the dimming cell 22.

However, in the dimming device 10 shown in FIG. 37, an anti-reflection layer 300 is provided on the outermost layer of the dimming cell 22, and anti-reflection layers 301 and 302 are provided on the front surface (upper surface in FIG. 37) and back surface (lower surface in FIG. 37) of the second light-transmitting plate 222. Note that the anti-reflection layers 300, 301, and 302 may include at least one of an anti-glare layer, an anti-reflection layer, and a low-reflection layer, as described above. Furthermore, the anti-reflection layers 300, 301, and 302 may have the same function and configuration as each other, or may have different functions and configurations as each other.

According to the light control device 10 shown in FIG. 37, for example, it is possible to improve the light transmittance by using the anti-reflection layers 300 and 301, while preventing reflections by using the anti-reflection layer 302.

Although not shown, functional layers such as the anti-reflection layers 300, 301, and 302 may be provided at other locations of the dimming device 10. For example, in addition to the anti-reflection layers 300, 301, and 302 shown in FIG. 37 or instead of the anti-reflection layers 300, 301, and 302, a functional layer such as an anti-reflection layer may be provided on the surface of the first light-transmitting plate 221. Also, any one or two of the anti-reflection layers 300, 301, and 302 shown in FIG. 37 may not be provided. In this way, it is possible to provide the anti-reflection layer 300 on at least one of the dimming cell 22 and the second light-transmitting plate 222. From the viewpoint of improving visibility, it is often preferable to place a functional layer such as an anti-reflection layer on the observer side. Therefore, in the example shown in FIG. 37, when the second light-transmitting plate 222 is placed closer to the observer side than the first light-transmitting plate 221, it is often preferable to place a functional layer such as an anti-reflection layer on the second light-transmitting plate 222 rather than the first light-transmitting plate 221.

The present invention is not limited to the above-described embodiments and modifications, but may include various aspects with various modifications that may be conceived by a person skilled in the art, and the effects achieved by the present invention are not limited to the above-described matters. Therefore, various additions, modifications, and partial deletions are possible for each element described in the claims and specification, without departing from the technical idea and intent of the present invention. For example, the above-described embodiments and modifications may be combined as appropriate.

10 Light control device 20 Curved surface 20a Three-dimensional curved surface 21 Light-transmitting plate 22 Light control cell 24 Optically transparent adhesive film 26 Hard coat layer 29 First resin substrate 30 Second resin substrate 31 First electrode layer 32 Second electrode layer 33 First alignment film 34 Second alignment film 35 Liquid crystal space 36 Sealing material 41 First polarizing plate 42 Second polarizing plate 43 First electrode alignment layer 44 Second electrode alignment layer 45 Retardation compensation film 45a Retardation compensation film 46 Adhesive layer 47 Protective layer 48 Polarizing layer 49 Liquid crystal layer 52 Spacer 53 Hard coat layer 55 Index matching layer 61 Dichroic dye 62 Liquid crystal 112 Lower laminate 112A Hard coat layer 112B Substrate 112C Hard coat layer 112D Linear polarizing plate 112E Alignment film 112F Plate layer 112G Transparent electrode 113 Upper laminate 113A hard coat layer 113B substrate 113C hard coat layer 113D transparent electrode 113E linear polarizer 113F alignment film 114 liquid crystal layer 115 spacer 122 lower laminate 122A substrate 122B transparent electrode 122C linear polarizer 122D plate layer 122E alignment film 123 upper laminate 123A substrate 123B transparent electrode 123C linear polarizer 123D alignment film 124 liquid crystal layer 125 spacer 132 lower laminate 142 lower laminate 142A adhesive layer 152 lower laminate 162 lower laminate plate 221 first light-transmitting plate 222 second light-transmitting plate 223 adhesive layer 225 sealant 226 sealed space 300 anti-reflection layer 301 anti-reflection layer 302 Anti-reflective layer

Claims (1)

A light control device comprising a first light-transmitting plate having a curved surface, a second light-transmitting plate, and a light control cell,
the dimming cell is disposed between the first light-transmitting plate and the second light-transmitting plate, and includes a first laminate including a first resin base material, a second laminate including a second resin base material, and a liquid crystal layer provided between the first laminate and the second laminate;
an optically transparent adhesive film is disposed between the curved surface of the first light-transmitting plate and the light control cell;
the second light-transmitting plate is attached to the other side of the dimming cell via an adhesive layer;
The optically transparent adhesive film is directly adhered to the curved surface of the first light-transmitting plate and the dimming cell;
the first light-transmitting plate and the second light-transmitting plate are glass plates;
A sealant is located between the first laminate and the second laminate,
The optically transparent adhesive film is made of OCA (Optical Clear Adhesive),
A light control device, wherein the adhesive layer disposed over the entire surface between the second light-transmitting plate and the light control cell is made of an OCA (Optical Clear Adhesive).