WO2019004160A1

WO2019004160A1 - Light modulating member, sun visor, and movable body

Info

Publication number: WO2019004160A1
Application number: PCT/JP2018/024102
Authority: WO
Inventors: 秀森戸; 悠子中西
Original assignee: 大日本印刷株式会社
Priority date: 2017-06-26
Filing date: 2018-06-26
Publication date: 2019-01-03
Also published as: JP6696616B2; JP2019207420A; JP2020129126A; JPWO2019004160A1

Abstract

A light modulating member (20) comprises: a pair of transparent base members (21, 22); a light modulating cell (30) disposed between the pair of the transparent base members (21, 22); and two joining layers (23, 24) which are disposed between the transparent base members (21, 22) and the light modulating cell (30) and which are for joining the transparent base members (21, 22) and the light modulating cell (30). The light modulating cell (30) can adjust the visible light transmission rate by electronic control. The storage elastic modulus of the joining layers (23, 24) is no more than 6×106Pa at 1 to 30ºC.

Description

Light control member, sun visor and moving body

The present invention relates to a light control member, a sun visor including the light control member, and a movable body including the sun visor.

Conventionally, a light control member capable of changing the light transmittance is known. As a method of adjusting the light transmittance of the light control member, a method using liquid crystal as shown in Patent Document 1 (JP6071094B) can be considered. The light control member of the system using the liquid crystal can be simply configured, the response of switching between the transmission state and the light shielding state is quick, and very high light shielding performance can be secured.

In the light control member, liquid crystal is disposed between the transparent substrates for protection. It is desirable that the transparent substrate be made of resin so as not to be damaged and that the edges of the fragments of the transparent substrate are not sharpened at the time of breakage.

However, local discoloration may occur in a light control member including a transparent base material formed of a resin. The local color change in the light control member is not preferable because it deteriorates the visibility through the light control member. The first invention is made in consideration of such a point, and an object thereof is to suppress a local color change in a light control member.

Moreover, in the light control member using a liquid crystal, color unevenness (hereinafter, simply referred to as "rainbow unevenness") in which colors are dispersed in a rainbow shape may be observed. Rainbow unevenness is not preferable because it deteriorates the visibility through the light control member. The second invention and the third invention are made in consideration of such a point, and an object thereof is to suppress the occurrence of rainbow unevenness in a light control member using liquid crystal.

<First Invention>
The first invention aims to suppress local discoloration in a light control member.

The light control member of the first invention is
A pair of transparent substrates,
A light control cell disposed between the pair of transparent substrates;
It comprises: two bonding layers disposed between the transparent base and the light control cell and bonding the transparent base and the light control cell;
The light control cell can adjust the visible light transmittance by electronic control,
The storage elastic modulus of the bonding layer is 6 × 10 ⁶ Pa or less at 1 ° C. or more and 30 ° C. or less.

In the light control member of the first invention, the storage elastic modulus of the bonding layer may be 1.4 × 10 ⁶ Pa or less at 1 ° C. or more and 30 ° C. or less.

In the light control member of the first invention, the thickness of at least one of the bonding layers may be 50 μm or more.

In the light control member of the first invention, the storage elastic modulus of the bonding layer may be 3 × 10 ⁴ Pa or more at 1 ° C. or more and 30 ° C. or less.

In the light control member of the first invention, the storage elastic modulus of the bonding layer may be 1 × 10 ⁵ Pa or more at 1 ° C. or more and 30 ° C. or less.

The light control member of the first invention may further include an easy adhesion layer disposed between the transparent substrate and the bonding layer.

The light control member of the first invention may further include a barrier layer disposed between the transparent substrate and the bonding layer.

The light control member of the first invention may further include an antireflective layer on the side of the transparent substrate opposite to the side on which the bonding layer is disposed.

In the light control member of the first invention, the light control cell may include a film liquid crystal of a TN type, a VA type, an IPS type or a GH type.

In the light control member of the first invention, the light control cell may include a TN type, a VA type, an IPS type, or a GH type glass liquid crystal.

The sun visor of the first invention comprises any of the light control members of the first invention.

The movable body of the first invention comprises any one of the light control members of the first invention or the sun visor of the first invention.

According to the first invention, it is possible to suppress local discoloration in the light control member.

<Second invention>
A second invention and an object of the present invention are to suppress the occurrence of rainbow unevenness in a light control member using liquid crystal.

The light control member of the second invention is
A transparent substrate,
A light control cell laminated on the transparent substrate,
The light control cell can adjust the visible light transmittance by electronic control,
The difference between the maximum value and the minimum value of retardation in the region where the light control cells of the transparent base material overlap is 100 nm or less.

In the light control member of the second invention,
The transparent substrate comprises polycarbonate,
The average value of retardation in a region where the light control cells of the transparent base material overlap may be 2000 nm or more.

In the light control member of the second invention,
The transparent substrate comprises polycarbonate,
The average value of retardation in a region where the light control cells of the transparent base material overlap may be 400 nm or less.

In the light adjusting member of the second aspect of the invention, melt volume flow rate of the transparent substrate may be equal to or less than 10 cm ^3/10 min.

In the light control member of the second invention,
The transparent substrate includes a curved surface,
The curvature radius of the curved surface of the transparent substrate may be 10 cm or more.

The sun visor of the second invention comprises any of the light control members of the second invention.

The movable body of the second invention comprises any one of the light control members of the second invention or the sun visor of the second invention.

According to the second invention, it is possible to suppress the occurrence of rainbow unevenness in the light control member.

<Third Invention>
A third aspect of the present invention is to suppress the occurrence of rainbow unevenness in a light control member using liquid crystal.

The light control member of the third invention is
A transparent support,
A light control unit supported by the transparent support;
The light control unit can adjust the visible light transmittance by electronic control,
The transparent support has a base layer having optical anisotropy, and a high retardation layer laminated on the base layer,
The retardation of the high retardation layer is 4000 nm or more.

In the light control member according to the third aspect of the present invention, the slow axis direction of the high retardation layer and the transmission axis direction of the two polarizing plates are 40 ° or more between the two polarizing plates in which the high retardation layer is disposed in cross nicol Transmittance of light having a wavelength of 550 nm or more and 650 nm or less that transmits the two polarizing plates in a direction inclined 45 ° from the normal direction of the high retardation layer in a state where the light is arranged at an angle of 50 ° or less [% The difference between the maximum value and the minimum value of the spectrum distribution of [1] may be 10 [%] or more.

In the light control member of the third invention, the slow axis direction of the high retardation layer and the transmission axis direction of the two polarizing plates in the transparent support between the two polarizing plates in which the transparent support is arranged in cross nicol Light having a wavelength of 550 nm or more and 650 nm or less that transmits through the two polarizing plates in the direction inclined 45 ° from the normal direction of the transparent support in a state in which The difference between the maximum value and the minimum value of the spectral distribution of the transmittance [%] may be 10 [%] or more.

In the light control member of the third invention,
The transparent support further includes a functional layer provided at a position separated from the light control unit from the base layer and the high retardation layer,
The functional layer may have at least one of an antireflective function and an antiglare function.

A sun visor according to a third aspect of the present invention includes any one of the light control members according to the third aspect.

The movable body of the third invention comprises any one of the light control members of the third invention or the sun visor of the third invention.

According to the third invention, it is possible to suppress the occurrence of rainbow unevenness in the light control member.

FIG. 1 is a perspective view schematically showing an automobile in which a sun visor equipped with a light control member is disposed. FIG. 2 is a schematic cross-sectional view showing a light control member according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing a light control cell of the light control member. FIG. 4 is a schematic exploded perspective view showing a light control member according to a second embodiment. FIG. 5 is a schematic cross-sectional view for explaining a light control cell of the light control member. FIG. 6 is a view for explaining the manufacturing process of the light control member. FIG. 7 is a view for explaining the manufacturing process of the light control member. FIG. 8 is a view for explaining the manufacturing process of the light control member. FIG. 9 is a view for explaining rainbow unevenness generated in the light control member. FIG. 10 is a graph for explaining that the polarization state changes due to reflection. FIG. 11 is a diagram for explaining that the polarization state changes due to reflection. FIG. 12 is a schematic exploded perspective view showing a light control member of the third embodiment. FIG. 13 is a schematic cross-sectional view for explaining the light control unit. FIG. 14 is a view for explaining the manufacturing process of the light control member. FIG. 15 is a diagram for describing a manufacturing process of the light control member. FIG. 16 is a view for explaining the manufacturing process of the light control member. FIG. 17 is a diagram for explaining a method of measuring rainbow unevenness. FIG. 18 is a graph of the transmittance of each wavelength of the base material layer measured in the state shown in FIG. FIG. 19 is a graph of the transmittance of each wavelength of the high retardation layer measured in the state shown in FIG. FIG. 20 is a graph of the transmittance of each wavelength of the transparent support measured in the state shown in FIG. FIG. 21 is a schematic cross-sectional view for explaining a modified example of the light control unit. FIG. 22 is a schematic cross-sectional view for explaining another modification of the light control unit.

Hereinafter, embodiments of the invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of easy illustration and understanding, the scale, the dimensional ratio in the vertical and horizontal directions, etc. are appropriately changed from those of the actual one and exaggerated.

First Embodiment
First, with reference to FIGS. 1 to 3, a first embodiment related to the first invention will be described.

FIG. 1 shows a sun visor 10 provided with a light control member 20 as an example to which the light control member 20 is applied. As shown in FIG. 1, a sun visor 10 is disposed inside the automobile 1 at a position facing the windshield. The sun visor 10 can reduce sunlight and the like incident through the windshield, and can provide an occupant of the automobile 1 with a good visibility.

The light control member 20 can adjust the transmittance of visible light, and can be, for example, 25% or more when the transmittance is adjusted high, and 10% or less when the transmittance is adjusted low. As shown in FIG. 2, the light control member 20 is provided between the first transparent base 21 and the second transparent base 22, which are a pair of transparent bases, and the first transparent base 21 and the second transparent base 22. A second light-adjusting cell 30 disposed in the second light-transmitting device, the first bonding layer 23 for bonding the first transparent base 21 and the light-modulating cell 30, and a second bonding for connecting the second transparent base 22 and the light-modulating cell 30 And a layer 24.

Hereinafter, each component of the light control member 20 will be described.

First, the first transparent base 21 and the second transparent base 22 will be described. The first transparent base 21 and the second transparent base 22 keep the shape of the light control cell 30 constant, and protect the light control cell 30 from scratches and dirt. In order to maintain the shape of the light control cell 30 constant, the first transparent base 21 and the second transparent base 22 have rigidity. Specifically, the bending strength of the first transparent base 21 and the second transparent base 22 is preferably 1000 MPa or more. The bending strength is defined in JIS K 7171 and can be measured, for example, by a universal testing machine manufactured by Instron.

Moreover, it is preferable that the 1st transparent base material 21 and the 2nd transparent base material 22 are formed with resin, and contain the polycarbonate which is resin with high glass transition temperature. By forming with resin, the 1st transparent substrate 21 and the 2nd transparent substrate 22 may become difficult to be damaged. It is preferable that the first transparent base 21 and the second transparent base 22 be formed so as to have a Charpy impact value of 1 kJ / m ² or more. The molecular weight of the polycarbonate contained in the first transparent substrate 21 and the second transparent substrate 22 is preferably 17,000 or more, and more preferably 20,000 or more. When the first transparent base 21 and the second transparent base 22 are formed of such a material, even if the first transparent base 21 and the second transparent base 22 are damaged, the first transparent base is formed. The edges of the fragments of the material 21 and the second transparent substrate 22 are not sharpened, and the risk of injury to the user of the light control member 20 can be reduced.

In addition, having "transparency" has transparency of the grade which can see through the other side from the one side of the said transparent base material via the 1st transparent base material 21 and the 2nd transparent base material 22. For example, it means having a visible light transmittance of 30% or more, more preferably 70% or more. The visible light transmittance is measured at a wavelength of 380 nm to 780 nm using a spectrophotometer (“UV-3100 PC” manufactured by Shimadzu Corporation, a product conforming to JIS K 0115) at each wavelength. Identified as the average value of

Moreover, it is preferable that the 1st transparent base material 21 and the 2nd transparent base material 22 have a thickness of 1 mm or more and 5 mm or less. With such a thickness, it is possible to obtain the first transparent base 21 and the second transparent base 22 which are excellent in strength and optical properties. The first transparent base 21 and the second transparent base 22 may be made of the same material and the same, or may be different from each other in at least one of the material and the configuration.

Next, the first bonding layer 23 and the second bonding layer 24 will be described. As described above, the first bonding layer 23 bonds the first transparent base 21 and the light control cell 30, and the second bonding layer 24 bonds the second transparent base 22 and the light control cell 30. . The first bonding layer 23 and the second bonding layer 24 are so-called OCA (Optical Clear Adhesive) or OCR (Optical Clear Resin). That is, the first bonding layer 23 and the second bonding layer 24 are layers of an optically transparent adhesive. The first bonding layer 23 and the second bonding layer 24 preferably have substantially the same refractive index as the first transparent base 21 and the second transparent base 22. In this case, reflection of light at each interface between the first transparent base 21 and the second transparent base 22 and the first bonding layer 23 and the second bonding layer 24 can be reduced.

In addition, the first bonding layer 23 and the second bonding layer 24 are in a room temperature environment (for example, 1 ° C. or more and 30 ° C. or less, in particular, in order to avoid uneven distribution of liquid crystals in the liquid crystal cell 35 Preferably, the storage elastic modulus at 15 ° C. or more and 25 ° C. or less is 6 × 10 ⁶ Pa or less, preferably 1.4 × 10 ⁶ Pa or less. In addition, the first bonding layer 23 and the second bonding layer 24 have a storage elastic modulus of 3 × in a room temperature environment in order to prevent generation of air bubbles by peeling from the first transparent base 21 and the second transparent base 22. It is preferably 10 ⁴ Pa or more, and more preferably 1 × 10 ⁵ Pa or more. The relationship between these defects and the storage modulus will be described in detail later.

The storage elastic modulus can be measured by a dynamic viscoelasticity measurement method according to JIS K 7244-1 by a solid viscoelasticity analyzer ("RSA-III" manufactured by TA Instruments). . The storage elastic modulus was measured at a temperature of −50 to 150 ° C., a frequency of 1 Hz, an attachment mode of torsional shear mode, and a temperature rising rate of 5 ° C./min.

The thickness of at least one of the first bonding layer 23 and the second bonding layer 24 is preferably 50 μm or more. When two members having rigidity are laminated via the bonding layer, air which has entered between the bonding layer and the member having rigidity is difficult to escape between the bonding layer and the member having rigidity, and enters as air bubbles. . Therefore, for example, when the first bonding layer 23 laminated with the second transparent base material 22 and the light control cell 30 is laminated on the first transparent base material 21 when the first bonding layer 23 is thinner than 50 μm, the first transparent Since both the base 21 and the second transparent base 22 have rigidity, air bubbles can easily enter between the first bonding layer 23 and the first transparent base 21. On the other hand, when laminating a rigid member and a non-rigid member through the bonding layer, the non-rigid member is curved even if air enters between the bonding layer and the non-rigid member. It is possible to induce the discharge of air by laminating while letting the air flow. Therefore, for example, even when the second bonding layer 24 is thinner than 50 μm, when laminating the light control cell 30 on the second bonding layer 24, air bubbles are generated between the second bonding layer 24 and the second transparent base 22. It is hard to get in. The first bonding layer 23 and the second bonding layer 24 preferably have a thickness of 1000 μm or less. When the thickness is thicker than 1000 μm, it is disadvantageous in terms of mass productivity, cost and strength. The first bonding layer 23 and the second bonding layer 24 may be made of the same material and the same, or may be different from each other in at least one of the material and the configuration.

Next, the light control cell 30 will be described. As shown in FIG. 3, the light control cell 30 includes a first polarizing plate 31, a second polarizing plate 32, and a liquid crystal cell 35 disposed between the first polarizing plate 31 and the second polarizing plate 32. Including. The light control cell 30 can change the alignment state of the liquid crystal of the liquid crystal cell 35 by electronic control such as voltage application. By changing the orientation of the liquid crystal, the polarization state of light traveling between the first polarizing plate 31 and the second polarizing plate 32 is controlled. Thereby, for example, it is possible to adjust the visible light transmittance of light traveling between the first polarizing plate 31 and the second polarizing plate 32 arranged in cross nicol or parallel nicol. Moreover, the thickness of the light control cell 30 is 100 micrometers or more and 800 micrometers or less, for example.

Cross Nicol means that the transmission axes of the two polarizers are orthogonal to each other, and parallel Nicol means that the transmission axes of the two polarizers are parallel to each other Say that

The first polarizing plate 31 and the second polarizing plate 32 decompose the incident light into two orthogonal polarization components (p polarization component and s polarization component) and vibrate in one direction (direction parallel to the transmission axis) Linearly polarized light component (for example, s-polarized light component) which transmits the linearly polarized light component (for example, p-polarized light component) with higher transmittance and vibrates in the other direction (parallel to the absorption axis) orthogonal to the one direction Has a function to absorb at a higher absorption rate. That is, by passing the first polarizing plate 31 and the second polarizing plate 32, it is possible to select and extract a linearly polarized light component vibrating in one direction (a direction parallel to the transmission axis).

As the liquid crystal cell 35, for example, liquid crystal of VA (Vertical Alignment) system, TN (Twisted Nematic) system, IPS (In Plane Switching) system or FFS (Fringe Field Switching) system can be used. The liquid crystal cell 35 may be a film liquid crystal in which liquid crystal is held by using a film made of resin as a base material, or may be a glass liquid crystal in which liquid crystal is held by using thin film glass as a base.

The light control cell 30 has a wire 30 c. The wiring 30 c is connected to, for example, a control device (not shown) provided in the automobile 1 and provides drive power and control signals to the dimming cell 30.

The orientation of the liquid crystal of the liquid crystal cell 35 can be changed by performing electronic control such as applying a voltage via the wiring 30 c to the light control cell 30. Depending on the orientation of the liquid crystal, the polarization direction of light transmitted through the liquid crystal cell 35 may change. For example, when light having a polarization component in a specific direction transmitted through the first polarizing plate 31 passes through the liquid crystal cell 35 in which the voltage is applied and the alignment of the liquid crystal is changed, the light transmitted through the liquid crystal cell 35 has its polarization direction Rotate 90 degrees. When the first polarizing plate 31 and the second polarizing plate 32 are arranged in cross nicol, light can be transmitted through the second polarizing plate 32 by rotating the polarization direction by 90 °. On the other hand, when light having a polarization component in a specific direction transmitted through the first polarizing plate 31 passes through the liquid crystal cell 35 in which the voltage is not applied and the orientation of the liquid crystal does not change, light passing through the liquid crystal cell 35 Does not rotate its polarization direction. When the first polarizing plate 31 and the second polarizing plate 32 are arranged in cross nicol, the light whose polarization direction has not been rotated can not be transmitted through the second polarizing plate 32. Thus, the transmission of light can be controlled by the presence or absence of the change in the alignment of the liquid crystals of the liquid crystal cell 35. Therefore, the light control cell 30 can adjust the visible light transmittance by electronic control.

The light control member 20 is not limited to the illustrated example, and may be provided with other functional layers expected to exhibit a specific function. In addition, one functional layer may exhibit two or more functions, and, for example, the first transparent base 21, the second transparent base 22, the first bonding layer 23 of the light control member 20, the first Some function may be given to at least one of the second bonding layer 24 and the light control cell 30. As a function that can be imparted to the light control member 20, as an example, a hard coat (HC) function having scratch resistance, an infrared ray shielding (reflection) function, an ultraviolet ray shielding (reflection) function, an antifouling function, etc. Can.

Next, an example of a method of manufacturing the light control member 20 will be described.

First, the second bonding layer 24 is laminated on the second transparent base material 22. The second bonding layer 24 is provided by being applied by, for example, a dispenser. Even if a level difference is generated on the surface of the second transparent base material 22 laminated with the second bonding layer 24, the level difference is compensated by the application of the second bonding layer 24. Air bubbles are less likely to occur between the second bonding layer 24 and the second bonding layer 24.

Next, the light control cell 30 is stacked on the second bonding layer 24. Since the light control cell 30 does not have rigidity, it can be laminated while pushing out the air between the light control cell 30 and the second bonding layer 24. Therefore, regardless of the thickness of the second bonding layer 24, bubbles are unlikely to be generated between the second bonding layer 24 and the dimming cell 30.

Next, the first bonding layer 23 is stacked on the light control cell 30. The first bonding layer 23 is provided by being applied by, for example, a dispenser. Even if there is a step in the light control cell 30, the step is compensated by the application of the first bonding layer 23, so that bubbles are unlikely to occur between the light control cell 30 and the first bonding layer 23.

Thereafter, the first transparent substrate 21 is laminated on the first bonding layer 23. Since the second transparent base material 22 laminated on the first transparent base material 21 and the first bonding layer 23 has rigidity, a step is generated on the surface of the first transparent base material 21 stacked on the first bonding layer 23 If you do, air may get into the steps. However, if the first bonding layer 23 has a sufficient thickness, the first bonding layer 23 deforms and thereby enters the step, which makes it easy to discharge the air in the step. Therefore, it is preferable that the thickness of the first bonding layer 23 be a sufficient thickness, specifically 50 μm or more, in order not to leave air bubbles in the step.

Each of the above steps is preferably performed in a low pressure environment or a vacuum environment. By this, it can suppress that a bubble mixes in the interface between each layer of the light control member 20. As shown in FIG.

By the way, such a light control member 20 may have local discoloration. As examined by the present inventors, the local discoloration of the light control member 20 causes pressure to be applied to the light control cell due to the deformation of the transparent base material formed of resin, and the liquid crystal is unevenly distributed in the liquid crystal cell of the light control cell. Was estimated to occur. Furthermore, it confirmed that the local discoloration of the light control member could be effectively suppressed by the countermeasure corresponding to this presumed cause.

Deformation of the transparent substrate formed of resin can be caused by heat. For example, when the light control member 20 is used inside a car 1 as a sun visor, it may be exposed to high temperatures. The glass transition temperature of the first transparent base 21 and the second transparent base 22 formed of resin is about 100 to 150.degree. Therefore, the first transparent base 21 and the second transparent base 22 may deform when exposed to a temperature of about 80.degree. As a result of the pressure applied to the light control cell 30 due to the deformation of the first transparent base 21 and the second transparent base 22 due to the heat, the liquid crystal is unevenly distributed in the liquid crystal cell 35 of the light control cell 30. It is thought that it is causing a color change.

It is desirable to prevent the uneven distribution of liquid crystal in the liquid crystal cell 35 of the light control cell 30 in order to prevent the light control member 20 from being locally discolored. As a result of intensive studies by the present inventors, it is possible to lower the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 so that the deformation of the first transparent base material 21 and the second transparent base material 22 is performed as the first bonding. It was confirmed that absorption by the layer 23 and the second bonding layer 24 can prevent the light control cell 30 from being affected by the deformation of the first transparent base 21 and the second transparent base 22. Specifically, by setting the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 in a room temperature environment to 6 × 10 ⁶ Pa or less, preferably 1.4 × 10 ⁶ Pa or less, the first transparent group is obtained. Even if the material 21 and the second transparent base material 22 were deformed by heat, it was confirmed that no local color change occurs in the light control member 20.

Also, in such a light control member 20, air bubbles may be generated between the first transparent base 21 and the first bonding layer 23 and between the second transparent base 22 and the second bonding layer 24. The As examined by the present inventors, the air bubbles are generated by being introduced when laminating the first transparent base material 21 and the first bonding layer 23 as described above, and the light control member 20 is exposed to high temperature However, it was estimated that it might occur.

When the light control member 20 is exposed to a high temperature, the first transparent base material 21 and the second transparent base material 22 may be deformed and peeled off from the first bonding layer 23 and the second bonding layer 24. Air can be generated as air enters. In addition, when the light control member 20 is exposed to a high temperature, the moisture and the like contained in the first transparent base 21 and the second transparent base 22 become a gas, and the gas is the first transparent base 21 and the first bonding layer 23 It is thought that air bubbles may be generated by peeling and entering between the second transparent base material 22 and the second bonding layer 24 and between the second transparent base material 22 and the second bonding layer 24.

As a result of intensive studies by the present inventors, air bubbles are generated between the first transparent base 21 and the first bonding layer 23 of the light control member 20 and between the second transparent base 22 and the second bonding layer 24. By setting the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 high in order to prevent the second bonding material 22 and the second transparent substrate 22 and the second It was confirmed that the generation of air bubbles can be suppressed by preventing the peeling between the bonding layer 24 and the other. Specifically, the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 in a room temperature environment is 3 × 10 ⁴ Pa or more, preferably 1 × 10 ⁵ Pa or more, even if exposed to high temperature It was confirmed that peeling between the first transparent base 21 and the first bonding layer 23 and between the second transparent base 22 and the second bonding layer 24 was prevented, and the generation of air bubbles was suppressed.

As described above, the light control member 20 according to the first embodiment includes the pair of

transparent bases

21 and 22, the light control cell 30 disposed between the pair of

transparent bases

21 and 22, and the transparent base The light control cell 30 includes two

bonding layers

23 and 24 disposed between the

materials

21 and 22 and the light control cell 30, and bonding the

transparent base members

21 and 22 and the light control cell 30. The visible light transmittance can be adjusted by control, and the storage elastic modulus of the bonding layers 23 and 24 is 6 × 10 ⁶ Pa or less at 1 ° C. or more and 30 ° C. or less. According to such a light control member 20, even if the first transparent base 21 and the second transparent base 22 are deformed by heat, the deformation of the first transparent base 21 and the second transparent base 22 can be reduced. It can be absorbed by the bonding layer 23 and the second bonding layer 24. Therefore, the light control cell 30 is not affected by the deformation of the first transparent base 21 and the second transparent base 22, and it is possible to make it difficult to cause uneven distribution of liquid crystal in the liquid crystal cell 35 of the light control cell 30. That is, it is possible to make it difficult for the light control member 20 to cause a local color change.

In the light control member 20 of the first embodiment, the thickness of at least one of the first bonding layer 23 and the second bonding layer 24 is 50 μm or more. In the first embodiment described above, the thickness of the first bonding layer 23 is 50 μm or more. According to such a light control member 20, even if a step is generated on the surface of the first transparent base 21 laminated with the first bonding layer 23, the step is compensated by the deformation of the first bonding layer 23. Air can not enter the level difference, and air bubbles do not easily enter. Therefore, generation of air bubbles in the light control member 20 can be suppressed.

Furthermore, in the light control member 20 according to the first embodiment, the storage elastic modulus of the bonding layers 23 and 24 is 3 × 10 ⁴ Pa or more at 1 ° C. or more and 30 ° C. or less. According to such a light control member 20, peeling is prevented between the first transparent base material 21 and the first bonding layer 23 and between the second transparent base material 22 and the second bonding layer 24 so that air bubbles can be prevented. Can be suppressed.

Note that various changes can be made to the above-described first embodiment.

For example, the light control member 20 according to the first embodiment described above may be provided between the first transparent substrate 21 and the first bonding layer 23 and / or between the second transparent substrate 22 and the second bonding layer 24. You may further provide the easily bonding layer arrange | positioned at. In the example shown in FIG. 2, the easy adhesion layer 21 a is disposed between the first transparent base 21 and the first bonding layer 23. The easy adhesion layer 21a is a layer for improving the adhesion and adhesiveness of the members on both sides of the easy adhesion layer. That is, the adhesion between the easy adhesion layer 21 a and the first transparent base 21 and the adhesion between the easy adhesion layer 21 a and the first bonding layer 23 are the adhesion between the first transparent base 21 and the first bonding layer 23. It is stronger than that. Also in the case where the easy adhesion layer is disposed between the second transparent substrate 22 and the second bonding layer 24, the adhesion between the easy adhesion layer and the second transparent substrate 22 and the easy adhesion layer and the second adhesion layer are also possible. The adhesion to the bonding layer 24 is stronger than the adhesion to the second transparent substrate 22 and the second bonding layer 24. Here, the adhesion strength of the two layers can be measured by a peeling test in accordance with JIS K 6854, for example, a universal tester manufactured by Instron. The easy adhesion layer is made of a transparent material, such as a resin containing acrylic or urethane. Moreover, the thickness of the easily bonding layer is, for example, 3 μm or more and 50 μm or less.

According to such an easily adhesive layer, the adhesion and adhesiveness between the first transparent base 21 and the first bonding layer 23 and / or the second transparent base 22 and the second bonding layer 24 are improved, The peeling between the first transparent base 21 and the first bonding layer 23 and between the second transparent base 22 and the second bonding layer 24 can be prevented. Therefore, the generation of air bubbles between the first bonding layer 23 and between the second transparent base material 22 and the second bonding layer 24 can be suppressed.

Further, the light control member 20 according to the first embodiment described above is configured between the first transparent base 21 and the first bonding layer 23 and / or between the second transparent base 22 and the second bonding layer 24. The device may further comprise a barrier layer disposed on In the example shown in FIG. 2, the barrier layer 22 a is disposed between the second transparent substrate 22 and the second bonding layer 24. The barrier layer 22 a is a layer for blocking the gas generated from the second transparent substrate 22 and preventing the second bonding layer 24 from being affected by the gas. For this purpose, the water vapor permeability of the barrier layer 22a is preferably 1 g / m ² · da or less. In addition, even when the barrier layer is disposed between the first transparent base 21 and the first bonding layer 23, the barrier layer blocks the gas generated from the first transparent base 21, and the first bonding layer is formed. It is possible to prevent 23 from being influenced by gas. The water vapor transmission rate can be measured at a temperature of 40 ° C. and a humidity of 100% RH using a water vapor transmission rate measuring apparatus (manufactured by MOCON, PERMATRAN-W3 / 31). The barrier layer is made of a transparent material, and a vapor deposited film of silicon oxycarbide (SiOC), for example, is used. The thickness of the barrier layer in this case is, for example, 50 nm or more and 1 μm or less. However, as long as the barrier layer is transparent, the production method may be produced by another method such as coating.

According to such a barrier layer, when heat is applied to the light control member 20, a gas such as moisture generated from the first transparent base 21 and / or the second transparent base 22 acts as the first bonding layer 23 and the like. And / or reaching the second bonding layer 24 can be suppressed. Therefore, it is possible to suppress air bubbles which may be generated by causing the gas to peel off and enter between the first transparent base 21 and the first bonding layer 23 and between the second transparent base 22 and the second bonding layer 24. Can.

Furthermore, the light control member 20 of the first embodiment described above is the side opposite to the side on which the first bonding layer 23 of the first transparent base material 21 is disposed, and / or the second side of the second transparent base material 22. You may further provide the anti-reflective layer arrange | positioned on the opposite side to the side by which the joining layer 24 is arrange | positioned. In the example shown in FIG. 2, the anti-reflection layer 21 b is disposed on the side opposite to the side on which the first bonding layer 23 of the first transparent substrate 21 is disposed. The antireflection layer is a layer for suppressing the reflection of visible light on the surface of the light control member 20 to improve the visible light transmittance. The antireflective layer is made of a transparent material, for example, a material having a refractive index lower than that of the first transparent substrate 21 and the second transparent substrate 22. The antireflective layer may also have microprotrusions arranged at a pitch less than the shortest wavelength of visible light (for example, 380 nm). The thickness of the antireflective layer is, for example, 20 μm or more and 500 μm or less in the case of bonding a film provided with the antireflective layer, and 10 μm or less in the case of coating or deposition.

Further, in the first embodiment described above, the liquid crystal cell 35 of the light control cell 30 uses a liquid crystal of a method that uses two polarizing plates 31 and 32 such as the VA method. However, liquid crystal of GH (Guest Host) system may be used as the light control cell 30. In the liquid crystal of the GH system, the transmittance can be controlled by changing the state in which the liquid crystal composition and the dichroic dye composition are randomly aligned and the state in which so-called twist alignment is performed by voltage control. When using the liquid crystal cell 35 which is a liquid crystal of GH system, it is not necessary to arrange one or both of the first polarizing plate 31 and the second polarizing plate 32 as shown in FIG.

Furthermore, in the first embodiment described above, the light control member 20 receives the supply of power from the outside, but a solar cell (not shown) is provided on a part of the light control member 20, and this solar cell May be configured to supply power. Furthermore, the irradiation light amount may be determined based on the output of the solar cell, and the transmittance may be automatically controlled accordingly.

Although the example in which the light control member 20 is adopted for the sun visor 10 is used in the above description, the application of the light control member 20 is not limited to the sun visor. As an example of another application, it is possible to adopt to the window part of a car, such as a side window or a sunroof of a car, or a train or an aircraft. Furthermore, it is also possible to adopt it to the window part of a building.

Although some modifications to the above-described first embodiment have been described above, it is of course possible to apply a plurality of modifications in combination as appropriate.

<Example>
Hereinafter, the first invention will be described in more detail using examples, but the first invention is not limited to these examples.

In Examples 1 to 9 and Comparative Examples 1 to 5, the light control member 20 in which at least one of the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 and the thickness of the first bonding layer 23 are different is prepared. . The 1st transparent substrate 21 and the 2nd transparent substrate 22 in light control member 20 of an example and a comparative example consist of polycarbonate, and thickness is 3 mm.

The storage elastic modulus can be adjusted, for example, by adding a tackifying resin such as terpene or a plasticizer such as dioctyl phthalate (DOP) or dioctyl adipate (DOA). Alternatively, the storage elastic modulus can be adjusted by adjusting the amount of the crosslinking agent or increasing or decreasing the number of functional groups of the main polymer of the material of the bonding layer.

About each Example and comparative example, immediately after manufacture of the light control member 20, ie, before a heat resistance test mentioned below, it observed and checked by using visual observation and using a magnifying glass whether bubbles were generated. Also, assuming that the light control member 20 is exposed to high temperature and used, a heat resistance test is performed to store the light control member 20 in a thermostatic bath at 80 ° C. for 400 hours, and air bubbles are generated after the heat resistance test. It was confirmed by visual observation and by using a magnifying glass whether or not discoloration due to uneven distribution of liquid crystal occurred. It should be noted that the confirmation of the color change due to the uneven distribution of the liquid crystal is performed in both the state where the transmittance of the light control member 20 is increased and decreased, and if the uneven distribution of liquid crystal is confirmed in any of them did.

The storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 in a room temperature environment, the thickness of the first bonding layer 23, and the air bubbles immediately after the manufacture of the light control member 20 in Examples 1 to 9 and Comparative Examples 1 to 5. The results of bubble generation after the heat resistance test and the uneven distribution of the liquid crystal after the heat resistance test are shown in Tables 1 and 2 below. The occurrence of air bubbles and the uneven distribution of liquid crystal were not observed with the magnifying glass but with A, and was not observed visually, but was observed with the magnifying glass with B visually C is added to each item. In Tables 1 to 3 referred to in the following, the result of bubble generation immediately after production is set as result 1, the result of bubble generation after heat resistance test is set as result 2, result of uneven distribution of liquid crystal after heat resistance test Are shown as result 3, respectively.

First, the results of Examples and Comparative Examples in which the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 are different are shown in Table 1 below.

As understood from the results of Examples 1 to 7 and Comparative Examples 1 and 2 shown in Table 1, samples in which the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is larger than 60 × 10 ⁵ Pa That is, in Comparative Example 1 and Comparative Example 2, uneven distribution of the liquid crystal was confirmed in the light control member 20 after the heat resistance test visually. As described above, the uneven distribution of the liquid crystal causes the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 to be too high, and the deformation of the first transparent base 21 and the second transparent base 22 due to heat is It is considered that this occurs because the first bonding layer 23 and the second bonding layer 24 can not absorb.

From the results shown in Table 1, it is understood that the uneven distribution of the liquid crystal can be suppressed by setting the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 to 60 × 10 ⁵ Pa or less. In particular, from the comparison of Example 1 and Example 2, it is preferable for suppressing the uneven distribution of the liquid crystal that the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is 14 × 10 ⁵ Pa or less. It is understood.

Further, as understood from the results of Examples 1 to 7 and Comparative Example 3, when the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is smaller than 0.3 × 10 ⁵ Pa, after the heat resistance test In the light control member 20 of the above, generation of air bubbles was also confirmed visually. As described above, the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is too low, and the bubbles cause deformation of the first transparent base 21 and the second transparent base 22 due to heat, and the first transparent. Between the first transparent substrate 21 and the first bonding layer 23 and between the second transparent substrate 22 and the second bonding layer 24 by the gas generated from the substrate 21 and the second transparent substrate 22 It is thought that it occurred to

From the results shown in Table 1, it is understood that the generation of air bubbles can be suppressed by the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 being 0.3 × 10 ⁵ Pa or more. Ru. In particular, from the comparison of Example 5 and Example 6, it is preferable for suppressing the generation of air bubbles that the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is 1 × 10 ⁵ Pa or more. It is understood.

Next, the results of Examples and Comparative Examples in which the thickness of the first bonding layer 23 is different are shown in Table 2 below.

As understood from the results of Examples 5, 8 and 9 and Comparative Examples 4 and 5 shown in Table 2, when the thickness of the first bonding layer 23 is smaller than 50 μm, immediately after the manufacture of the light control member 20. Air bubbles were generated. As described above, since the thickness of the first bonding layer 23 is too thin, the air bubbles are stacked on the first bonding layer 23 when the first transparent base 21 and the first bonding layer 23 are stacked. (1) It is considered that the surface of the transparent base material 21 enters a step. In the results of Table 2, the bubbles were observed even in the results 2 after the heat resistance test in Comparative Examples 4 and 5 because the bubbles were generated immediately after the production, so the bubbles were observed even after the heat resistance test It is.

From the results shown in Table 2, it is understood that the generation of air bubbles can be suppressed by the thickness of the first bonding layer 23 being 50 μm or more. In particular, it is understood from the comparison of Example 8 and Example 9 that the thickness of the first bonding layer 23 is 75 μm or more, which is preferable for suppressing the generation of air bubbles.

By the way, as described above, by arranging the easy adhesion layer between the transparent base material and the bonding layer, the adhesion and adhesiveness between the transparent base material and the bonding layer are improved, and the transparent base material and the bonding layer It is possible to prevent peeling between them. Therefore, it is considered that the generation of air bubbles after the heat resistance test can be suppressed by arranging the easy adhesion layer.

Further, as described above, by disposing the barrier layer between the transparent base and the bonding layer, it is possible to suppress that the gas generated from the transparent base reaches the bonding layer. Therefore, it is thought that the air bubbles which may be generated by gas coming in between the transparent base material and the bonding layer can be suppressed. That is, by disposing the barrier layer, it is considered that the generation of air bubbles after the heat resistance test can be suppressed.

About the Example and comparative example which have arrange | positioned the easily bonding layer or the barrier layer, it shows below. In Example 10, an easy adhesion layer made of an acrylic resin is provided as an additional layer, and an easy adhesion layer made of a urethane resin is provided as an additional layer. It is set as Example 11. In addition, Example 12 in which a barrier layer was provided as an additional layer in Example 6 was taken. Moreover, what provided the easily bonding layer as an additional layer in Example 7 was set as Example 13, and what provided the barrier layer as an additional layer was set as Example 14. FIG. Furthermore, what provided the easily bonding layer as an additional layer in the comparative example 3 was set as the comparative example 6, and what provided the barrier layer as an additional layer was set as the comparative example 7. FIG.

The results of Examples 6, 7 and 10 to 14 and Comparative Examples 3, 6 and 7 are shown in Table 3 below.

As understood from the comparison of the results of Examples 6 and 7 and Examples 10 to 14 shown in Table 3, the provision of the easily adhesive layer or the barrier layer further suppresses the generation of air bubbles after the heat resistance test. It was confirmed that it was possible. On the other hand, as understood from the results of Comparative Examples 3, 6, and 7, when the storage elastic modulus of the first bonding layer 23 and the second bonding layer 24 is too low, even if the easily adhesive layer or the barrier layer is provided, After the heat resistance test, the generation of air bubbles was confirmed. It is considered that the air bubbles are generated when the storage elastic modulus is too low, even if the easily adhesive layer or the barrier layer is provided, the bonding layer peels off.

Further, deformation of the first transparent base 21 and the second transparent base 22 due to heat is more likely to occur as the glass transition temperature is lower. The glass transition temperature (Tg) of the transparent base material made of polycarbonate used in the above-mentioned Examples 1 to 9 is 145 ° C. However, if the transparent substrate is a transparent substrate containing polycarbonate as the main component but also containing other components, the glass transition temperature may be lowered.

In Examples 3 to 5, the component configurations of the transparent base material were changed, and light control members having a glass transition temperature of 125 ° C. were produced, and were set to Examples 15 to 17. The results of Examples 3-5 and 15-17 are shown in Table 4 below.

As understood from the results shown in Table 4, it was confirmed that the results after the heat resistance test did not change even when the glass transition temperature of the transparent substrate was 125 ° C. Therefore, it is understood that when the glass transition temperature of the transparent substrate is at least 125 ° C. or more, problems such as generation of air bubbles and generation of uneven distribution of liquid crystal are less likely to deteriorate the visibility through the light control member. .

Second Embodiment
Similar to the first embodiment, the sun visor 10 shown in FIG. 1 can be illustrated as an example to which the light control member 120 is applied. As shown in FIG. 1, a sun visor 10 is disposed inside the automobile 1 at a position facing the windshield 5. The sun visor 10 can reduce sunlight and the like incident through the windshield 5 and can provide a good view to the occupants of the automobile 1.

The second embodiment related to the second invention will be described below with reference to FIGS. 4 to 11.

The light control member 120 can adjust the transmittance of visible light. As shown in FIG. 4, the light control member 120 is laminated on the first transparent substrate 121 and the second transparent substrate 122, which are a pair of substrates, and the first transparent substrate 121 and the second transparent substrate 122. Light control cell 130, a first bonding layer 123 for bonding the first transparent base material 121 and the light control cell 130, and a second bonding layer 124 for bonding the second transparent base material 122 and the light control cell 130 And.

Hereinafter, each component of the light control member 120 will be described.

First, the first transparent base 121 and the second transparent base 122 will be described. The first transparent base material 121 and the second transparent base material 122 are for maintaining the shape of the light control cell 130 constant and protecting the light control cell 130 from scratches and dirt. It is preferable that the first transparent substrate 121 and the second transparent substrate 122 contain polycarbonate. When the first transparent base material 121 and the second transparent base material 122 contain polycarbonate, the retardation of the first transparent base material 121 and the second transparent base material 122 described later can be easily controlled and manufactured. . Moreover, in the light control member 120 according to the second embodiment, the molecular weight of polycarbonate contained in the first transparent base material 121 and the second transparent base material 122 is preferably 17,000 or more, and 20,000 or more. It is more preferable that When the first transparent substrate 121 and the second transparent substrate 122 are formed of such a material, even if the first transparent substrate 121 and the second transparent substrate 122 are broken, the first transparent substrate 121 is formed. And the edge of the fragments of the second transparent substrate 122 is not sharpened, and the risk of injury to the user of the light control member 120 can be reduced. However, the present invention is not limited to this, and the first transparent base 121 and the second transparent base 122 may be formed of a glass plate. When the first transparent substrate 121 and the second transparent substrate 122 are formed of a glass plate, the user of the light control member 120 is injured when the first transparent substrate 121 and the second transparent substrate 122 are broken. In order to reduce the risk of causing it, it is preferable to provide an anti-scattering sheet on the surface.

In addition, having "transparency" has transparency of the grade which can see through the other side from the one side of the said transparent base material through the 1st transparent base material 121 and the 2nd transparent base material 122. For example, it means having a visible light transmittance of 30% or more, more preferably 70% or more. The visible light transmittance is measured at a wavelength of 380 nm to 780 nm using a spectrophotometer (“UV-3100 PC” manufactured by Shimadzu Corporation, a product conforming to JIS K 0115) at each wavelength. Identified as the average value of

Moreover, it is preferable that the 1st transparent base material 121 and the 2nd transparent base material 122 have a thickness of 0.1 mm or more and 10 mm or less, preferably 0.5 mm or more and 5 mm or less. If it is such thickness, the 1st transparent substrate 121 and the 2nd transparent substrate 122 which were excellent in intensity and an optical characteristic can be obtained. The first transparent substrate 121 and the second transparent substrate 122 may be made of the same material and the same, or may be different from each other in at least one of the material and the configuration.

The first transparent base 121 and the second transparent base 122 are preferably manufactured by extrusion. According to extrusion molding, the first transparent base material 121 and the second transparent base material 122 can be formed in a uniform and flat plate shape. In order to manufacture in plate shape by extrusion molding, it is preferable that the melt volume flow rate of the 1st transparent substrate 121 and the 2nd transparent substrate 122 is 10 cm < ³ > / 10 minutes or less. The melt volume flow rate is measured at a temperature of 300 ° C. and a weight of 1.2 kg according to ISO1133.

Next, the first bonding layer 123 and the second bonding layer 124 will be described. As described above, the first bonding layer 123 bonds the first transparent base material 121 and the light control cell 130, and the second bonding layer 124 bonds the second transparent base material 122 and the light control cell 130. . In the second embodiment, the first bonding layer 123 and the second bonding layer 124 are so-called OCA (Optically Clear Adhesive) or OCR (Optically Clear Resin). That is, the first bonding layer 123 and the second bonding layer 124 are transparent and have adhesiveness. The first bonding layer 123 and the second bonding layer 124 preferably have substantially the same refractive index as the first transparent base 121 and the second transparent base 122. In this case, reflection of light at each interface between the first transparent base 121 and the second transparent base 122 and the first bonding layer 123 and the second bonding layer 124 can be reduced.

The first bonding layer 123 and the second bonding layer 124 preferably have a thickness of 25 μm to 1000 μm. If the thickness is smaller than 25 μm, the distortion of the light control member can not be absorbed by the bonding surface, so that defects of the air bubble and the light control member (for example, color unevenness due to a liquid crystal GAP failure) tend to occur. On the other hand, if the thickness is thicker than 1000 μm, it is disadvantageous in terms of mass productivity, cost and strength. The first bonding layer 123 and the second bonding layer 124 may be made of the same material and the same, or may be different from each other in at least one of the material and the configuration.

Next, the light control cell 130 will be described. As shown in FIG. 5, the light control cell 130 includes a first polarizing plate 131, a second polarizing plate 132, and a liquid crystal cell 135 disposed between the first polarizing plate 131 and the second polarizing plate 132. Including. The first polarizing plate 131 and the second polarizing plate 132 decompose the incident light into two orthogonal polarization components (p polarization component and s polarization component) and vibrate in one direction (direction parallel to the transmission axis) A function of transmitting a linearly polarized light component (eg, p-polarized light component) and absorbing a linearly polarized light component (eg, s-polarized light component) oscillating in the other direction (a direction parallel to the absorption axis) orthogonal to the one direction. Have. As the liquid crystal cell 135, for example, liquid crystal of VA (Vertical Alignment) system, TN (Twisted Nematic) system, IPS (In Plane Switching) system or FFS (Fringe Field Switching) system can be used. The light control cell 130 can change the alignment of the liquid crystal of the liquid crystal cell 135 by electronic control such as voltage application. By changing the orientation of the liquid crystal, the polarization state of light traveling between the first polarizing plate 131 and the second polarizing plate 132 is controlled. Thereby, for example, it is possible to adjust the visible light transmittance of light traveling between the first polarizing plate 131 and the second polarizing plate 132 arranged in cross nicol or parallel nicol. Cross Nicol means that the transmission axes of the two polarizers are orthogonal to each other, and parallel Nicol means that the transmission axes of the two polarizers are parallel to each other Say that Moreover, the thickness of the light control cell 130 is 100 micrometers or more and 800 micrometers or less, for example.

The liquid crystal cell 135 may be a film liquid crystal in which liquid crystal is held by using a film made of resin as a base material, or may be a glass liquid crystal in which liquid crystal is held by using thin film glass as a base. In the case of film liquid crystal, the liquid crystal cell 135 can be provided with flexibility.

As shown in FIG. 4, the light control cell 130 has a wire 130 c. The wiring 130 c is connected to a control device (not shown) provided in the automobile 1 and provides drive power and control signals to the dimming cell 130. The wiring 130c is preferably formed of a transparent conductor. In this case, the wiring 130c is not substantially visible from the outside, and the appearance of the light control member 120 can be improved.

The orientation of the liquid crystal of the liquid crystal cell 135 can be changed by performing electronic control such as applying a voltage through the wiring 130 c to the light control cell 130. Depending on the orientation of the liquid crystal, the polarization direction of light transmitted through the liquid crystal cell 135 may change. For example, when light having a polarization component in a specific direction transmitted through the first polarizing plate 131 passes through the liquid crystal cell 135 in which the voltage is applied and the alignment of the liquid crystal is changed, the light transmitted through the liquid crystal cell 135 has its polarization direction Rotate 90 degrees. When the first polarizing plate 131 and the second polarizing plate 132 are disposed in cross nicol, light can be transmitted through the second polarizing plate 132 by rotating the polarization direction by 90 °. On the other hand, when light having a polarization component in a specific direction transmitted through the first polarizing plate 131 passes through the liquid crystal cell 135 in which the voltage is not applied and the orientation of the liquid crystal does not change, light passing through the liquid crystal cell 135 Does not rotate its polarization direction. When the first polarizing plate 131 and the second polarizing plate 132 are arranged in cross nicol, light whose polarization direction has not been rotated can not be transmitted through the second polarizing plate 132. Thus, the transmission of light can be controlled by the presence or absence of the change in the alignment of the liquid crystals in the liquid crystal cell 135. Therefore, the light control cell 130 can adjust the visible light transmittance by electronic control.

In a plan view of the light control member 120, the first transparent base material 121, the second transparent base material 122, the first bonding layer 123, the second bonding layer 124, and the light control cell 130, which are components of the light control member 120, It has substantially the same shape. In the example shown in FIG. 4, each component of the light adjustment member 120 has a rectangular shape in plan view. The light control cell 130 includes a region overlapping with the first transparent substrate 121 and the second transparent substrate 122. Moreover, it is preferable that the light control cell 130 does not protrude from the first transparent base 121 and the second transparent base 122 in a plan view. That is, the dimension of the light control cell 130 in plan view is preferably smaller than the dimensions of the first transparent base 121 and the second transparent base 122.

The light control member 120 is not limited to the illustrated example, and may be provided with other functional layers expected to exhibit a specific function. In addition, one functional layer may exhibit two or more functions, and, for example, the first transparent substrate 121, the second transparent substrate 122, the first bonding layer 123, and the first light modulation member 120 may be used. Some function may be given to at least one of the second bonding layer 124 and the light control cell 130. Examples of functions that can be imparted to the light control member 120 include an anti-reflection (AR) function, a hard coat (HC) function having scratch resistance, an infrared ray shielding (reflection) function, an ultraviolet ray shielding (reflection) function, A dirty function etc. can be illustrated.

Next, an example of a method of manufacturing the light control member 120 will be described with reference to FIGS.

First, the first transparent base 121 and the second transparent base 122 are manufactured in a flat plate shape by extrusion molding.

Next, as shown in FIG. 6, the first bonding layer 123 is bonded to one side of the first transparent base 121. Similarly, the second bonding layer 124 is bonded to one side of the second transparent base 122.

Thereafter, as shown in FIG. 7, the second transparent base 122 is bonded to one surface of the light control cell 130 via the second bonding layer 124, whereby the light control cell 130 is connected to the second transparent base 122. Are stacked. The light control cell 130 is provided with a wire 130 c.

Then, as shown in FIG. 8, the first transparent base 121 is bonded to the other surface of the light control cell 130, whereby the light control cell 130 is stacked on the first transparent base 121. This bonding is realized by the first bonding layer 123 previously bonded to the first transparent substrate 121.

Each of the above steps is preferably performed in a low pressure environment, preferably in a vacuum environment. By this, when bonding the 1st bonding layer 123 and the 2nd bonding layer 124, it can avoid that a bubble mixes in an interface.

By the way, as above-mentioned, in the light control member 120, rainbow nonuniformity may be observed. In particular, when the sun visor 10 including the light control member 120 is disposed inside the automobile 1, rainbow unevenness has been observed. If rainbow unevenness occurs, the view through the light control member 120 will be deteriorated. As a result of intensive investigations by the present inventors, if there is a large variation in retardation in the transparent substrate (first transparent substrate 121) on the side opposite to the side of the light control member 120 facing the user, rainbow unevenness is observed It is confirmed that it can be done. When these phenomena were repeatedly examined, it was estimated that rainbow unevenness would occur due to the cause described below, and it was further confirmed that rainbow unevenness could be effectively suppressed by measures corresponding to this presumed cause.

The retardation is the refractive index (n _{x in the} direction of the slow axis) in which the refractive index at each position in the plane of the first transparent substrate 121 is measured using light having a measurement wavelength of 548.2 nm. product of the refractive index in the direction (fast axis direction) and (the difference between _{_{_{n y) (n x -n y}}} ), the thickness of the first transparent substrate 121 (d) orthogonal to) the slow axis direction It is defined by (d × (n _x −n _y )) and is expressed in units of length (nm).

When light passes through a member having retardation, the polarization state changes. Therefore, as shown in FIG. 9, when the transparent base material 155 having retardation is disposed between the incident side polarizing plate 151 and the output side polarizing plate 152 and light L1 is made incident from the incident side polarizing plate 151 side, it is transparent. The amount of light emitted from the output side polarizing plate 152 changes according to the retardation of the transparent substrate 155 as compared to the case where the substrate 155 is not disposed. That is, when the transparent substrate 155 having retardation is disposed between the incident side polarizing plate 151 and the output side polarizing plate 152, the visible light transmittance from the incident side polarizing plate 151 to the output side polarizing plate 152 is changed. The variation of the visible light transmittance varies depending on the wavelength. Therefore, the wavelength at which the visible light transmittance is high changes according to the retardation of the transparent substrate 155, and the light emitted from the output side polarizing plate 152 is visually recognized in a color according to the retardation of the transparent substrate 155.

When the retardation at each position in the plane of the transparent substrate 155 varies, the polarization state of light transmitted through the transparent substrate 155 varies in accordance with the retardation at each position in the plane of the transparent substrate 155. For this reason, at each position in the plane of the transparent substrate 155, the wavelength at which the visible light transmittance is high changes. Therefore, as shown in FIG. 9, when the transparent base material 155 having a variation in retardation is disposed between the incident side polarizing plate 151 and the output side polarizing plate 152 and light L1 is made incident from the incident side polarizing plate 151 side, The light emitted from the output side polarizing plate 152 has high transmittance of light of different wavelengths at each position of the output side polarizing plate 152. For this reason, the light emitted from each position of the output side polarizing plate 152 becomes light of different wavelengths, and the color varies, and is recognized as rainbow unevenness. Such rainbow unevenness is not dependent on the incident side polarizing plate 151 and the output side polarizing plate 152, and for example, even if the incident side polarizing plate 151 and the output side polarizing plate 152 are arranged in cross nicol, they are arranged in parallel nicols Even if, it will occur.

That is, it was inferred that the rainbow unevenness is caused by the fact that light in a polarized state is transmitted through a member having variation in retardation and is further changed in the polarized state.

On the other hand, even without using a polarizer such as a polarizing plate as shown in FIG. 9, light in a polarized state is generated in the following case. As shown in FIG. 10, light incident at an angle on the interface of an object of different refractive index is reflected by a polarization component (p polarization component) parallel to the incidence surface and a polarization component (s polarization component) perpendicular to the incidence surface. The rates are different. In particular, light incident at a certain angle has a reflectance of zero for the polarization component parallel to the plane of incidence. That is, when incident light is reflected, the polarization state changes. This angle is known as the Brewster's angle. For example, at an interface of glass and air, light incident at an incident angle of about 60 degrees changes its polarization state when it is reflected.

Therefore, as shown in FIG. 11, for example, in the interior of the automobile 1, the light L3 incident on the windshield 5 at about 60 degrees changes its polarization state when it is reflected. When light L4 whose polarization state has changed is incident on the sun visor 10 provided with the light control member 120 of the second embodiment described above, the transparent substrate on the side facing the windshield 5 (here, the first transparent substrate 121) Rainbow unevenness occurs in accordance with the variation in retardation in the area overlapping the light control cell 130 of FIG.

The suppression of the occurrence of rainbow unevenness can be achieved by avoiding the dispersion of the wavelength at which the transmittance increases at each position in the plane of the transparent substrate. For this purpose, it is conceivable to suppress the variation in retardation in the area overlapping the light control cell 130 of the first transparent base material 121. Specifically, by setting the variation in retardation of the first transparent substrate 121 to 100 nm or less, it is possible to suppress the occurrence of variation in color that is visually recognized as rainbow unevenness.

In addition, as the retardation decreases, the change in visible light transmittance for each wavelength with respect to the change in retardation decreases. That is, even if there is a variation in retardation, the visible light transmittance for each wavelength hardly changes. Therefore, when the variation in retardation is sufficiently small, rainbow unevenness does not occur as much as visually confirmed. Specifically, when the average of retardation in a region overlapping with the light control cell 130 of the first transparent substrate 121 is 400 nm or less, preferably 200 nm or less, the variation of visible light transmittance for each wavelength according to the retardation is It becomes sufficiently small, and rainbow unevenness due to variations in retardation can be effectively made inconspicuous.

Alternatively, as the retardation increases, the change in visible light transmittance for each wavelength with respect to the change in retardation increases. Further, as the retardation increases, light of a plurality of wavelengths is more likely to be transmitted, so the transmitted light is likely to be mixed and perceived. That is, even if there is variation in retardation, the visible light transmittance for each wavelength fluctuates greatly, so the transmittance for another wavelength is high even if the transmittance for a certain wavelength is low. For this reason, it is hard to visually recognize the change of the color mixing of the light to permeate | transmit. Specifically, when the average of retardation in a region overlapping the light control cell 130 of the first transparent substrate 121 is 2000 nm or more, preferably 3000 nm or more, the variation of visible light transmittance for each wavelength according to retardation is Even if the visible light transmittance fluctuates due to the dispersion of retardation, the color mixture is visually recognized and it is difficult to visually recognize a change in color. That is, rainbow unevenness can be effectively made inconspicuous.

In addition, the retardation in the area | region which overlaps with the light control cell 130 of the 1st transparent base material 121 is measured as follows. First, the transparent base material 155 as an object as shown in FIG. 9 is disposed between the incident side polarizing plate 151 and the output side polarizing plate 152, and light is made to enter from the incident side polarizing plate 151 side. Then, when observed from the side of the exit-side polarizing plate, the portion of the transparent base material 155 that is the object of the change in color when viewed visually is divided by 6 cm square. The incident side polarizing plate 151 and the output side polarizing plate 152 are arranged in parallel nicol, for example. The divided portion of the target transparent base material 155 is divided into three in the longitudinal direction and three in the lateral direction, and the retardation is measured at the respective central portions of the divided portions. That is, nine points of retardation are measured at equal intervals in the transparent substrate 155 partitioned by 6 cm square. The retardation can be measured by a parallel Nicol rotation method using KOBRA-WR (manufactured by Oji Scientific Instruments Co., Ltd.) or by a rotation analyzer method using RETS-1250VA (manufactured by Otsuka Electronics Co., Ltd.).

The difference between the maximum value and the minimum value of the nine measured retardations is taken as the variation of retardation. Also, the average of the nine measured retardation values is taken as the average of the retardation.

As described above, the light control member 120 of the second embodiment includes the first transparent base material 121, the light control cell 130 stacked on the first transparent base material 121, the first transparent base material 121, and the light control member 120. And a first bonding layer 123 for bonding to the optical cell 130. The light control cell 130 can adjust the visible light transmittance by electronic control. The difference between the maximum value and the minimum value of retardation in the region where the light control cells 130 of the first transparent base material 121 overlap is 100 nm or less. According to such a light control member 120, since the variation in retardation is small, it is possible to avoid that the wavelength of light with high transmittance is different at each position in the plane of the first transparent base material 121. Therefore, even if light in a polarized state is incident on the first transparent base material 121, the transmittance of the first transparent base material 121 has less variation due to wavelength, so that light emitted from the light control cell 130 has rainbow unevenness. The occurrence can be effectively suppressed. That is, the generation of rainbow unevenness caused by the retardation of the first transparent base material 121 in the light control member 120 can be suppressed.

Moreover, in the light control member 120 of the second embodiment, the first transparent base material 121 contains polycarbonate, and the average value of retardation in the region where the light control cells 130 of the first transparent base material 121 overlap is 2000 nm. It is above. According to such a light control member 120, since the retardation of the first transparent substrate 121 is sufficiently large, the change in visible light transmittance for each wavelength with respect to the change in retardation is large, and the transmitted light is mixed and perceived It will be easier. For this reason, even if the visible light transmittance fluctuates due to the variation in retardation, it becomes difficult to visually recognize a change in color that may cause rainbow unevenness. That is, the generation of rainbow unevenness caused by the retardation of the first transparent base material 121 in the light control member 120 can be suppressed.

Furthermore, in the light control member 120 according to the second embodiment, the first transparent base material 121 contains polycarbonate, and the average value of retardation in a region where the light control cells 130 of the first transparent base material 121 overlap is 400 nm. It is below. According to such a light control member 120, since the retardation of the first transparent base material 121 is sufficiently small, the variation of the visible light transmittance for each wavelength with respect to the variation of the retardation becomes small. For this reason, even if the visible light transmittance fluctuates due to the variation in retardation, it becomes difficult to visually recognize a change in color that may cause rainbow unevenness. That is, the generation of rainbow unevenness caused by the retardation of the first transparent base material 121 in the light control member 120 can be suppressed.

Note that various changes can be made to the above-described second embodiment.

In the light control member 120 according to the second embodiment described above, the first transparent base material 121 and the second transparent base material 122 are stacked on both sides of the light control cell 130, but only on one side of the light control cell 130. A transparent substrate may be laminated. That is, for example, only the first transparent base material 121 may be stacked on the light control cell 130.

Further, in the second embodiment described above, the liquid crystal cell 135 of the light control cell 130 uses a liquid crystal of a system that uses two

polarizing plates

131 and 132 such as the VA system. However, liquid crystal of GH (Guest Host) type may be used as the light control cell 130. In the liquid crystal of the GH system, the transmittance can be controlled by changing the state in which the liquid crystal composition and the dichroic dye composition are randomly aligned and the state in which so-called twist alignment is performed by voltage control. Therefore, it is not necessary to use a polarizing plate in the GH type liquid crystal.

Even when a GH type liquid crystal that does not require a polarizing plate is used as the light control cell 130, one side of the light control member 120 because the dichroic dye composition contained in the GH liquid crystal functions as a polarizer. For example, in the case where the retardation of the first transparent base material 121 varies, when light in a polarized state is incident from the side of the first transparent base material 121, rainbow unevenness occurs as in the second embodiment described above.

Even in this case, as described above, by setting the variation in retardation of the first transparent substrate 121 to 100 nm or less, it is possible to make the rainbow unevenness not visually confirmed.

Furthermore, in the second embodiment described above, although the first transparent base material 121 and the second transparent base material 122 are manufactured by extrusion molding, the first transparent base material 121 and the second transparent base material 122 are , May be manufactured by injection molding. Transparent substrates produced by injection molding may have a three-dimensional shape. The transparent substrate produced by injection molding may include a curved surface as a three-dimensional shape. However, if the curved surface of the transparent substrate has a three-dimensional shape with a small radius of curvature, it becomes difficult to adjust the retardation as intended during the production of the transparent substrate. Therefore, the dispersion | variation in retardation arises in a transparent base material, and it becomes easy to produce a rainbow nonuniformity in the light control member 120. FIG. Therefore, the radius of curvature of the curved surface of the transparent substrate is preferably large. Specifically, the radius of curvature of the curved surface of the transparent base material in the area overlapping the light control cell 130 is preferably 10 cm or more, and more preferably 20 cm or more. In addition, the dispersion | variation in the retardation of the transparent base material manufactured by injection molding can be made small, for example by performing compression molding at the time of injection molding.

In the second embodiment described above, OCA is employed as the first bonding layer 123 and the second bonding layer 124 for bonding the first transparent base material 121 and the second transparent base material 122 to the light control cell 130. However, it is also possible to join them by heat sealing, for example. In this case, since the first transparent base material 121 and the second transparent base material 122 can be bonded to both surfaces of the light control cell 130 in one process, there is no need to bond each surface one by one, and the manufacturing process is simplified. be able to.

Furthermore, in the second embodiment described above, the light control member 120 receives power supply from the outside, but a solar cell (not shown) is provided on a part of the light control member 120, and this solar cell May be configured to supply power. Furthermore, the irradiation light amount may be determined based on the output of the solar cell, and the transmittance may be automatically controlled accordingly.

Although the example in which the light control member 120 is adopted for the sun visor 10 is used in the above description, the application of the light control member 120 is not limited to the sun visor. As an example of another application, it is possible to adopt to the window part of a car, such as a side window or a sunroof of a car, or a train or an aircraft. Furthermore, it is also possible to adopt it to the window part of a building.

<Example>
Hereinafter, the second invention will be described in more detail using Examples, but the second invention is not limited to these Examples.

Different transparent substrates were prepared as examples and comparative examples. Examples 1 to 6 and Comparative Example 1 are transparent substrates produced by extrusion. Example 7 and Comparative Examples 2 to 6 are transparent substrates manufactured by injection molding.

As shown in FIG. 9, the transparent substrate 155 was disposed between the incident side polarizing plate 151 and the output side polarizing plate 152. The incident side polarizing plate 151 and the output side polarizing plate 152 were arranged in cross nicol. When the light source was arranged on the incident side polarizing plate 151 side and observed from the output side polarizing plate 152 side, the presence or absence of rainbow unevenness was confirmed. In addition, the portion of the transparent base material that is the subject of the most visual change in color was divided by 6 cm square, and retardation was measured at regular intervals at nine points on the transparent base plate partitioned by 6 cm square.

The variation and average of retardation measured at 9 points and the results of Examples and Comparative Examples visually observed for rainbow unevenness are shown in Table 5 below. As described above, the variation in retardation represents the difference between the maximum value and the minimum value of the nine measured retardations, and the average of the retardations represents the average of the measured nine retardation values. As for rainbow unevenness, A was not confirmed visually, B was slightly confirmed by careful visual observation, but B was visually confirmed but not visually impaired C is attached to the extent that it does not become and D is attached to those that are clearly confirmed visually and obstruct the view.

As understood from the examples 1 to 7 and the comparative examples 1 to 6, when the variation in retardation is 100 nm or less, the rainbow unevenness does not obstruct the visual field. Moreover, even if the average of retardation is 400 nm or less or 2000 nm or more, rainbow unevenness was visually confirmed when the variation in retardation is greater than 100 nm. From Examples 1 to 7 and Comparative Examples 1 to 6, when the difference between the maximum value and the minimum value of retardation is 100 nm or less, the occurrence of rainbow unevenness caused by the retardation of the transparent substrate is suppressed. It is understood that

Moreover, as understood from the comparison of Examples 1, 3 and 5, when the average of retardation is 2000 nm or more, rainbow unevenness is slightly confirmed, and when 3000 nm or more, rainbow unevenness is visually confirmed. It will not be done. Therefore, when the average of retardation is 2000 nm or more, preferably 3000 nm or more, generation of rainbow unevenness caused by retardation of the transparent substrate can be further suppressed.

Furthermore, as understood from the comparison of Examples 2, 4 and 6, when the average of retardation is 400 nm or less, rainbow unevenness is slightly confirmed, and when 200 nm or less, rainbow unevenness is visually confirmed. It will not be done. Therefore, when the average of retardation is 400 nm or less, preferably 200 nm or less, it can be said that the generation of rainbow unevenness caused by the retardation of the transparent substrate can be further suppressed.

Third Embodiment
Similar to the first and second embodiments, the sun visor 10 shown in FIG. 1 can be illustrated as an example to which the light control member 220 is applied. As shown in FIG. 1, a sun visor 10 is disposed inside the automobile 1 at a position facing the windshield 5. The sun visor 10 can reduce sunlight and the like incident through the windshield 5 and can provide a good view to the occupants of the automobile 1.

The third embodiment relating to the third invention will be described below with reference to FIGS. 12 to 22.

The light control member 220 can adjust the transmittance of visible light. As shown in FIG. 12, the light control member 220 is supported by the first transparent support 230 and the second transparent support 240, which are a pair of supports, and the first transparent support 230 and the second transparent support 240. Light control unit 250, a first bonding layer 223 bonding the first transparent support 230 and the light control unit 250, and a second bond connecting the second transparent support 240 and the light control unit 250. And a layer 224.

Hereinafter, each component of the light control member 220 will be described.

First, the first transparent support 230 and the second transparent support 240 will be described. The first transparent support 230 and the second transparent support 240 are members for protecting the light control unit 250 from scratches and dirt while supporting the light control unit 250 so as to maintain a constant shape. As shown in FIG. 12, the first transparent support 230 includes a first base layer 231, a first high retardation layer 232 laminated on the first base layer 231, a first base layer 231, and a first base layer 231. And a first functional layer 233 provided at a position farther from the light adjustment unit 250 than the high retardation layer 232. The second transparent support 240 also has a second base layer 241. In the example shown in FIG. 12, in the first transparent support 230, the first high retardation layer 232 is provided between the first base layer 231 and the first functional layer 233, and the first functional layer 233. Is a layer forming one surface of the light control member 220. The transparent support provided with the first functional layer 233, that is, the first transparent support 230, uses the light control member 220 in order to effectively exhibit the function of the first functional layer 233 as described later by the user. Sometimes, it is preferable that the side facing the user is provided.

In addition, having "transparency" has transparency which can see through the other side from the one side of the said transparent support body via the 1st transparent support body 230 and the 2nd transparent support body 240. For example, it means having a visible light transmittance of 30% or more, more preferably 70% or more. The visible light transmittance is measured at a wavelength of 380 nm to 780 nm using a spectrophotometer (“UV-3100 PC” manufactured by Shimadzu Corporation, a product conforming to JIS K 0115) at each wavelength. Identified as the average value of

The first and second base layers 231 and 241 are layers serving as the base of the first and second

transparent supports

230 and 240, and are formed of a resin having a sufficient thickness. The resin forming the first and second base layers 231 and 241 generally has optical anisotropy. That is, the first and second base layers 231 and 241 have retardation. For example, the retardation of the first and second base layers 231 and 241 is 50 nm or more and 12000 nm or less. In addition, the retardation of the first and second base material layers 231 and 241 may vary by 100 nm or more at each position in the plane. The retardation means the refractive index (n _x ) in the direction (slow axis direction) in which the refractive index at each position in the plane of the base layer is measured using light having a measurement wavelength of 548.2 nm. The product (d × (d × (a)) of the difference (n _x −n _y ) with the refractive index (n _y ) in the direction (fast axis direction) orthogonal to the slow axis direction and the thickness (d) of the substrate layer It is defined by n _x- n _y )) and is expressed in units of length (nm). In addition, with the variation of retardation, for example, the retardation is measured at nine points at equal intervals in the first and second base material layers 231 and 241 partitioned by 6 cm square, and the maximum value and the minimum value of the nine measured retardations are measured. Means the difference between The retardation can be measured by a parallel Nicol rotation method using KOBRA-WR (manufactured by Oji Scientific Instruments Co., Ltd.) or by a rotation analyzer method using RETS-1250VA (manufactured by Otsuka Electronics Co., Ltd.).

The first and second base layers 231 and 241 preferably contain at least one of acrylic and polycarbonate, and more preferably contain acrylic. For example, the first and second base layers 231 and 241 may have a configuration in which polycarbonate is laminated between two acrylics. In addition, the molecular weight of the acrylic or polycarbonate contained in the first and second base material layers 231 and 241 is preferably 17,000 or more, and more preferably 20,000 or more. When the first and second base layers 231 and 241 are formed of such a material, even if the first and second base layers 231 and 241 are broken, the first and second base layers 231, The edges of the 241 fragments are not sharpened, and the risk of injury to the user of the light control member 220 can be reduced. However, not only this but the 1st and 2nd substrate layers 231 and 241 may be formed with a glass film. If the first and second base layers 231 and 241 are formed of glass film, there is a risk that the user of the light control member 220 may be injured when the first and second base layers 231 and 241 are broken. In order to reduce, it is preferable to provide an anti-scattering sheet on the surface.

The first and second base layers 231 and 241 preferably have a thickness of 0.1 mm or more and 10 mm or less, preferably 0.5 mm or more and 5 mm or less. With such a thickness, it is possible to obtain the first and second base layers 231 and 241 excellent in strength and optical properties. The first and second base layers 231 and 241 may be identical to each other with the same material, or may be different from each other in at least one of the material and the structure.

The first and second base layers 231 and 241 can be manufactured by injection molding. Manufactured by injection molding, the first and second base layers 231 and 241 can have a three-dimensional shape, for example, a curved surface. However, when manufactured by injection molding, the retardation of the first and second base material layers 231 and 241 tends to vary. The variation in retardation of the first and second base material layers 231 and 241 can be reduced to a certain extent by, for example, compression molding at the time of injection molding, but the variation in retardation can not be eliminated.

The first high retardation layer 232 has higher retardation than the first base layer 231. The retardation of the first high retardation layer 232 is, for example, 4000 nm or more on average. The first high retardation layer 232 contains a resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), for example. The first high retardation layer 232 can be manufactured by stretching such a resin. Since the first high retardation layer 232 has retardation, it has a slow axis direction and a fast axis direction. The thickness of the first high retardation layer 232 is, for example, 10 μm or more and 300 μm or less.

The first functional layer 233 may have at least one of an antireflective function (also referred to as an AR function or an LR function) and an antiglare function (also referred to as an AG function). In addition, the first functional layer 233 may have other functions. The thickness of the first functional layer 233 is, for example, 50 nm or more and 20 μm or less.

Next, the first bonding layer 223 and the second bonding layer 224 will be described. As described above, the first bonding layer 223 bonds the first transparent support 230 and the light control unit 250, and the second bonding layer 224 bonds the second transparent support 240 and the light control unit 250. . In the third embodiment, the first bonding layer 223 and the second bonding layer 224 are so-called OCA (Optically Clear Adhesive) or OCR (Optically Clear Resin). That is, the first bonding layer 223 and the second bonding layer 224 are transparent and have adhesiveness. The first bonding layer 223 and the second bonding layer 224 preferably have substantially the same refractive index as the first transparent support 230 and the second transparent support 240. In this case, the reflection of light at each interface between the first transparent support 230 and the second transparent support 240, and the first bonding layer 223 and the second bonding layer 224 can be reduced.

The first bonding layer 223 and the second bonding layer 224 preferably have a thickness of 25 μm to 1000 μm. If the thickness is smaller than 25 μm, the distortion of the light control member can not be absorbed by the bonding surface, so that defects of the air bubble and the light control member (for example, color unevenness due to a liquid crystal GAP failure) tend to occur. On the other hand, if the thickness is thicker than 1000 μm, it is disadvantageous in terms of mass productivity, cost and strength. The first bonding layer 223 and the second bonding layer 224 may be made of the same material and the same, or may be different from each other in at least one of the material and the configuration.

Next, the light control unit 250 will be described. As shown in FIG. 13, the light control unit 250 includes a first polarizing plate 251, a second polarizing plate 252, and a liquid crystal unit 255 disposed between the first polarizing plate 251 and the second polarizing plate 252. Including. The first bonding layer 223 is provided on the side of the first polarizing plate 251 of the light control unit 250, and the first transparent support 230 is stacked. Similarly, the second bonding layer 224 is provided on the side of the second polarizing plate 252 of the light control unit 250, and the second transparent support 240 is stacked. Moreover, as shown in FIG. 12, the light control unit 250 has the wiring 250c. The wiring 250 c is connected to a control device (not shown) provided in the automobile 1 and provides drive power and control signals to the dimming unit 250. The wiring 250c is preferably formed of a transparent conductor. In this case, the wiring 250c is not substantially visible from the outside, and the appearance of the light control member 220 can be improved. The thickness of the light control unit 250 is, for example, 100 μm or more and 3 mm or less.

The first polarizing plate 251 and the second polarizing plate 252 separate the incident light into two orthogonal polarization components (p polarization component and s polarization component) and vibrate in one direction (direction parallel to the transmission axis) A function of transmitting a linearly polarized light component (eg, p-polarized light component) and absorbing a linearly polarized light component (eg, s-polarized light component) oscillating in the other direction (a direction parallel to the absorption axis) orthogonal to the one direction. Have. The first polarizing plate 251 and the second polarizing plate 252 are arranged in cross nicol or parallel nicol. Cross Nicol means that the transmission axes of the two polarizers are orthogonal to each other, and parallel Nicol means that the transmission axes of the two polarizers are parallel to each other Say

As the liquid crystal unit 255, for example, liquid crystal of VA (Vertical Alignment) system, TN (Twisted Nematic) system, IPS (In Plane Switching) system or FFS (Fringe Field Switching) system can be used. The liquid crystal unit 255 may be a film liquid crystal in which liquid crystal is held by using a film made of resin as a base material, or may be a glass liquid crystal in which liquid crystal is held by using thin film glass as a base. In the case of film liquid crystal, the liquid crystal unit 255 can be provided with flexibility.

The light control unit 250 can change the orientation of the liquid crystal of the liquid crystal unit 255 by performing electronic control such as applying a voltage through the wiring 250 c. Depending on the orientation of the liquid crystal, the polarization direction of light transmitted through the liquid crystal unit 255 may change. For example, when light having a polarization component in a specific direction transmitted through the first polarizing plate 251 passes through the liquid crystal unit 255 in which the voltage is applied and the orientation of the liquid crystal is changed, the light transmitted through the liquid crystal unit 255 has its polarization direction Rotate 90 degrees. When the first polarizing plate 251 and the second polarizing plate 252 are arranged in cross nicol, light can be transmitted through the second polarizing plate 252 by rotating the polarization direction by 90 °. On the other hand, when light having a polarization component in a specific direction transmitted through the first polarizing plate 251 passes through the liquid crystal unit 255 in which the voltage is not applied and the orientation of the liquid crystal does not change, light passing through the liquid crystal unit 255 Does not rotate its polarization direction. When the first polarizing plate 251 and the second polarizing plate 252 are arranged in cross nicol, light whose polarization direction has not been rotated can not be transmitted through the second polarizing plate 252. Thus, the transmission of light can be controlled by the presence or absence of the change in the orientation of the liquid crystal of the liquid crystal unit 255. Therefore, the light control unit 250 can adjust the visible light transmittance by electronic control.

In plan view of the light control member 220, the first transparent support 230, the second transparent support 240, the first bonding layer 223, the second bonding layer 224, and the light control unit 250, which are components of the light control member 220, It has substantially the same shape. In the example shown in FIG. 12, each component of the light adjustment member 220 has a rectangular shape in plan view. The dimming unit 250 includes an area overlapping the first transparent support 230 and the second transparent support 240. Moreover, in plan view, it is preferable that the light control unit 250 does not protrude from the first transparent support 230 and the second transparent support 240. That is, the dimension of the light adjustment unit 250 in plan view is preferably smaller than the dimensions of the first transparent support 230 and the second transparent support 240.

The light control member 220 is not limited to the illustrated example, and may be provided with a functional layer expected to exhibit a specific function other than the first functional layer 233 of the first transparent support. good. In addition, one functional layer may exhibit two or more functions, and, for example, the first transparent support 230, the second transparent support 240, the first bonding layer 223, and the first light modulation member 220 may be used. Some function may be given to at least one of the second bonding layer 224 and the light control unit 250. As a function that can be imparted to the light control member 220, for example, a hard coat (HC) function having scratch resistance, an infrared ray shielding (reflection) function, an ultraviolet ray shielding (reflection) function, an antifouling function, etc. Can.

Next, an example of a method of manufacturing the light adjusting member 220 will be described with reference to FIGS.

First, the first base layer 231 and the second base layer 241 are manufactured by injection molding. The first high retardation layer 232 and the first functional layer 233 are stacked on the first base layer 231, and the first transparent support 230 is manufactured. The first functional layer 233 is formed to be the surface of the first transparent support 230.

Next, as shown in FIG. 14, the first bonding layer 223 is bonded to the surface of the first transparent support 230 opposite to the side on which the first functional layer 233 is provided. In addition, the second bonding layer 224 is bonded to one surface of the second transparent support 240.

Thereafter, as shown in FIG. 15, the second transparent support 240 is bonded to one surface of the light control unit 250 via the second bonding layer 224, whereby the light control unit 250 is fixed to the second transparent support 240. Are stacked. The light adjustment unit 250 is provided with a wire 250 c.

Then, as shown in FIG. 16, the first transparent support 230 is bonded to the other surface of the light control unit 250, whereby the light control unit 250 is stacked on the first transparent support 230. This bonding is realized by the first bonding layer 223 previously bonded to the first transparent support 230.

Each of the above steps is preferably performed in a low pressure environment, preferably in a vacuum environment. By this, when bonding the 1st bonding layer 223 and the 2nd bonding layer 224, it can avoid that a bubble mixes in an interface.

By the way, as above-mentioned, in the light control member 220, rainbow nonuniformity may be observed. In particular, when the sun visor 10 including the light control member 220 is disposed inside the automobile 1, rainbow unevenness has been observed. If rainbow unevenness occurs, the view through the light control member 220 will be deteriorated. As a result of intensive investigations by the inventors of the present invention, it is considered that the transparent support (first transparent support 230) on the side opposite to the side facing the user of the light control member 220 includes a member having variation in retardation. It was confirmed that rainbow unevenness could be observed. That is, the rainbow unevenness occurred due to the variation in the retardation of the first base layer 231 of the first transparent support 230. When these phenomena were repeatedly examined, it was estimated that rainbow unevenness would occur due to the cause described below, and it was further confirmed that rainbow unevenness could be effectively suppressed by measures corresponding to this presumed cause.

When light passes through a member having retardation, the polarization state of the light changes. Therefore, as shown in FIG. 17, when a member having retardation is disposed between the incident side polarization plate 271 and the emission side polarization plate 272 and the light L5 is made incident from the incident side polarization plate 271 side, the first transparent support Compared to the case where the body 230 is not disposed, the amount of light emitted from the exit side polarizing plate 272, that is, the visible light transmittance, changes according to the retardation of the member disposed between the polarizing plates. The change in the visible light transmittance varies depending on the wavelength. Therefore, the wavelength at which the visible light transmittance is high changes according to the retardation of the member disposed between the polarizing plates, and the light L6 emitted from the output side polarizing plate 272 corresponds to the retardation of the member disposed between the polarizing plates It is visible in the color.

The polarization state of light transmitted through a member having a variation in retardation at each position in the plane varies depending on the retardation at each position in the plane of the member. For this reason, the wavelength with high visible light transmittance changes at each position in the plane of the member. Therefore, as shown in FIG. 17, when a member having variation in retardation is disposed between the incident side polarizing plate 271 and the output side polarizing plate 272 and the light L5 is made incident from the incident side polarizing plate 271 side, the output side polarized light The light L 6 emitted from the plate 272 has high transmittance of light of different wavelengths at each position of the output side polarizing plate 272. For this reason, the light emitted from each position of the output side polarizing plate 272 becomes light of different wavelengths, and the color varies, and is recognized as rainbow unevenness. Such rainbow unevenness does not depend on the arrangement of the incident side polarizing plate 271 and the output side polarizing plate 272, and for example, even when the incident side polarizing plate 271 and the output side polarizing plate 272 are arranged in cross nicol, parallel nicol Even if arranged by, it occurs.

That is, it was inferred that the rainbow unevenness is caused by the fact that light in a polarized state is transmitted through a member having variation in retardation, and is further changed in polarization state. In particular, as described above, in the retardation, the refractive index (n _x ) in the direction in which the refractive index of the member is large (slow axis direction) and the refractive index (n in the fast axis direction) in the direction orthogonal to the slow axis direction the difference between _y) _(the n x -n _y), the product _(d × (n x _-n y between the thickness of the member (d) [nm])) is defined by [nm]. Therefore, as shown in FIG. 17, when observed from a direction inclined by an angle θ from the normal direction (front direction) of the member, the substantial thickness of the member is d / cos θ [nm], and therefore the retardation is It gets bigger. That is, the variation in retardation also increases. For this reason, when observing from a direction inclined by an angle θ from the front direction, rainbow unevenness is more easily observed than when observing from the front direction.

On the other hand, even without using a polarizer such as a polarizing plate as shown in FIG. 17, light in a polarized state is generated in the following case. As shown in FIG. 10, light incident at an angle to the interface of an object with different refractive index, in other words light incident at an incident angle larger than 0 °, has a polarization component (p-polarization component) parallel to the incident surface and the incident surface. The reflectance differs with the polarization component (s-polarization component) perpendicular to. In particular, light incident at a certain incident angle has a reflectance of zero for the polarization component parallel to the incident surface. That is, when incident light is reflected, the polarization state changes. This angle is known as the Brewster's angle. For example, at an interface of glass and air, light incident at an incident angle of about 60 ° changes its polarization state when it is reflected.

Therefore, as shown in FIG. 11, for example, inside the automobile 1, the light L3 incident on the windshield 5 at an incident angle of about 60 ° changes its polarization state when it is reflected. When the light L4 whose polarization state has changed is incident on the sun visor 10 including the light control member 220 of the third embodiment described above, the transparent support on the side facing the windshield 5 (here, the first transparent support 230) Rainbow unevenness occurs according to the variation of retardation in the area overlapping the light control unit 250 of FIG.

In order to suppress the occurrence of rainbow unevenness, it has been considered to suppress variations in the retardation of members. However, as described above, the variation in the rediation of the first base material layer 231 is caused by the production of the first base material layer 231 by injection molding, and the variation in the retardation of the first base material layer 231 is It was difficult to suppress it to such an extent that rainbow unevenness did not occur. Therefore, the inventors of the present invention repeatedly study, and by providing the first high retardation layer 232 with large retardation on the first transparent support 230 to enlarge the retardation of the first transparent support 230, the occurrence of rainbow unevenness is realized. We have found that it can be effectively suppressed.

As the retardation of the member increases, the change in visible light transmittance for each wavelength of light transmitted through the member with respect to the change in retardation increases due to the difference in the transmittance of each polarization component. As the retardation increases, light of various wavelengths is more likely to be transmitted, so the transmitted light is likely to be mixed and perceived. Even if the member has a variation in retardation, the visible light transmittance for each wavelength greatly fluctuates and light of various wavelengths is transmitted, so the color of the transmitted light is difficult to be visually recognized visually due to color mixing. Specifically, when the retardation in the region overlapping the light control unit 250 of the first transparent support 230 is 4000 nm or more, the variation of the visible light transmittance for each wavelength according to the retardation becomes very large, and the retardation Even if the visible light transmittance fluctuates due to the variation, the color mixture is visually recognized and the color is difficult to be recognized. That is, rainbow unevenness can be effectively made inconspicuous.

In addition, in order to prevent rainbow unevenness from being observed in the light control member 220 including the first transparent support 230, not only the normal direction (front direction) of the first transparent support 230 but also the normal to the first transparent support 230 It is preferable that the occurrence of rainbow unevenness is suppressed also in the direction inclined from the direction and the observation becomes difficult. Since the light control member 220 is often used in a mode observed at an angle within 45 ° from the normal direction, particularly, a mode observed at an angle within 35 °, the first transparent support In the direction inclined 45 ° from the normal direction of 230, preferably in the direction inclined 35 °, the occurrence of rainbow unevenness is preferably suppressed.

As described above, in order to make the rainbow unevenness inconspicuous, it is only necessary that the light is mixed and visually recognized and the color is not easily recognized. As a result of repeated investigations by the present inventors, in order to make rainbow unevenness inconspicuous, the first transparent support 230 is placed between two

polarizing plates

271 and 272 arranged in cross nicol as shown in FIG. 2 with the slow axis direction of the first high retardation layer 232 and the transmission axis direction of the two

polarizing plates

271 and 272 in the first transparent support 230 disposed at an angle of 40 ° to 50 °. Maximum and minimum values of the spectral distribution [%] of light having a wavelength of 550 nm or more and 650 nm or less that transmits two

polarizing plates

271 and 272 in a direction inclined 45 ° from the normal direction of the first transparent support 230 Is preferably 10% or more, and the wavelength of transmitting the two

polarizing plates

271 and 272 in the direction inclined 35.degree. From the normal direction of the first transparent support 230 is 550 nm to 650 nm. The difference between the maximum value and the minimum value of the spectral distribution of the light transmittance of the lower [%] is and finding a more preferable to be 12.5 [%] or more.

Furthermore, if rainbow unevenness is not noticeable in the first high retardation layer 232, it is considered that the color of the transmitted light is not recognized due to color mixture. Therefore, it is considered that even with the first transparent support 230 having the first high retardation layer 232 and the first base layer 231, light of various wavelengths can be transmitted to suppress the occurrence of rainbow unevenness. As a result of investigations by the present inventors, as a result of the first high retardation layer 232, the slow axis direction of the first high retardation layer 232 and the two polarizing plates between the two

polarizing plates

271 and 272 disposed in cross nicol Two

polarizing plates

271 and 272 are inclined in the direction inclined 45 ° from the normal direction of the first high retardation layer 232 in a state where the transmission axis direction of 271 and 272 is arranged to form an angle of 40 ° to 50 °. It is preferable that the difference between the maximum value and the minimum value of the spectral distribution of the transmittance [%] of light having a wavelength of 550 nm or more and 650 nm or less which transmits light be 10% or more. Transmittance of light having a wavelength of 550 nm or more and 650 nm or less incident on the first high retardation layer 232 transmitted in the direction inclined 35 ° from the normal direction of the first high retardation layer 232 [ The difference between the maximum value and the minimum value of the spectral distribution of] has been finding more preferable to be 12.5 [%] or more.

The transmittance of light passing through the first high retardation layer 232 and the first transparent support 230 described above is considered to be light with a wavelength of 550 nm or more and 650 nm or less, the retardation of the first high retardation layer 232 is sufficiently large. Because the variation in visible light transmittance for each wavelength of light transmitted is increased due to the fact that there is a difference of 10% or more between the maximum value and the minimum value of transmittance in this wavelength range, in other wavelength ranges This is because it is considered that light of sufficient transmittance is generated and light of various wavelengths is transmitted.

In the following, the above-described effect of making the rainbow unevenness inconspicuous by providing the first high retardation layer 232 on the first transparent support 230 will be described using a specific example.

FIG. 18 shows the first base material layer 231 having a retardation of 450 nm and a variation of retardation of 150 nm at each in-plane position of the two

polarizing plates

271 and 272 arranged in cross nicol as shown in FIG. With the first base layer 231 interposed therebetween in directions inclined 0 °, 20 °, 40 °, 60 ° from the normal direction of the first base layer 231, with the first base layer 231 interposed therebetween. It is a graph showing the spectral distribution of light transmittance [%] in each wavelength range which transmits 272. As understood from FIG. 18, depending on the inclination angle from the normal direction of the first base layer 231, the wavelength range in which the transmittance is increased is largely different. Specifically, light in the wavelength range of 490 nm to 510 nm is strongly observed in the direction (front direction) tilted by 0 ° from the normal direction of the first base layer 231, and in the direction tilted by 20 °, the wavelength range of 410 nm to 420 nm and The light of 600 nm to 700 nm is strongly observed, the light of wavelength 430 nm to 550 nm is strongly observed in the direction inclined 40 °, and the light of wavelength 560 nm to 620 nm is strongly observed in the direction inclined 60 °. As described above, since the wavelength of light strongly observed differs depending on the angle to be observed, rainbow unevenness occurs in the light control member 220 including the first transparent support of only the layer having retardation like the first base layer 231. It can.

FIG. 19 shows the first high retardation layer between two

polarizing plates

271 and 272 arranged in crossed nicols as shown in FIG. 17 with a first high retardation layer 232 having a retardation of 4000 nm or more, specifically 8400 nm. With the slow axis direction of 232 and the two

polarizing plates

271 and 272 arranged at an angle of 45 °, 0 °, 20 °, 40 °, 60 ° from the normal direction of the first high retardation layer 232 It is a graph showing the spectral distribution of the transmittance | permeability of the light in each wavelength range which permeate | transmits two

polarizing plates

271 and 272 which pinched | interposed the 1st high retardation layer 232 in the direction which inclined (degree). As understood from FIG. 19, in each graph in which the inclination angles from the normal direction of the first high retardation layer 232 are different, there are many wavelength regions in which the transmittance is high. That is, at each inclination angle, the color is not recognized due to color mixture, and no rainbow unevenness occurs. Therefore, in the first transparent support 230 having the first high retardation layer 232, even if it has the first base layer 231 with some variation in retardation, it is considered that no rainbow unevenness occurs.

FIG. 20 shows the first transparent support 230 having the first base layer 231 and the first high retardation layer 232, as shown in FIG. 17, between the two

polarizing plates

271 and 272 arranged in cross nicol. In a state in which the slow axis direction of the high retardation layer 232 and the two

polarizing plates

271 and 272 are disposed at an angle of 45 °, 0 ° and 20 ° from the normal direction of the first transparent support 230 It is a graph showing the spectral distribution of the transmittance | permeability of the light in each wavelength range which permeate | transmits two

polarizing plates

271 and 272 which pinched | interposed the 1st transparent support body 230 in the direction inclined 40 degrees and 60 degrees. As understood from FIG. 20, in each of the graphs in which the inclination angles from the normal direction of the first transparent support 230 are different, there are many wavelength ranges in which the transmittance is high. That is, it is considered that at each inclination angle, the color is not recognized due to color mixture, and rainbow unevenness does not occur.

Table 6 below shows the retardation of the first high retardation layer 232 between two

polarizing plates

271 and 272 arranged in crossed nicols as shown in FIG. 17 for the first high retardation layer 232 having a retardation of 4000 nm or more. With the axial direction and the two

polarizing plates

271 and 272 arranged at an angle of 45 °, the first high retardation layer 232 is inclined at an angle of 5 ° from 0 ° to 65 ° from the normal direction of the first high retardation layer 232 Maximum value, minimum value, and maximum value of the spectral distribution of the transmittance [%] of light in the wavelength range of 550 nm to 650 nm transmitted through the two

polarizing plates

271 and 272 sandwiching the first high retardation layer 232 when observed It shows the difference between the value and the minimum value. Moreover, at each angle, the presence or absence of rainbow unevenness was visually observed. The code “A” in the table represents that no rainbow unevenness was visually observed, the code “B” represents that rainbow unevenness was observed only to such an extent that the view would not be disturbed, and the code “C” "" Indicates that the rainbow non-uniformity was clearly observed to such an extent that the view was obstructed.

As understood from Table 6, as the inclination angle of the first high retardation layer 232 from the normal direction increases, the difference between the maximum value and the minimum value of the spectral distribution of transmittance tends to decrease. . In addition, when the difference between the maximum value and the minimum value of the spectral distribution of transmittance is 10% or more, rainbow unevenness is observed only to such an extent that the view is not hindered. In particular, when the difference between the maximum value and the minimum value of the spectral distribution of transmittance is 12.5% or more, rainbow unevenness is not observed visually.

Further, in the direction inclined 45 ° from the normal direction of the first high retardation layer 232, the difference between the maximum value and the minimum value of the spectral distribution of the transmittance is 10% or more. Therefore, when the inclination angle from the normal direction of the first high retardation layer 232 is 45 ° or less, rainbow unevenness that hinders visibility is not observed. In particular, in the direction inclined 35 ° from the normal direction of the first high retardation layer 232, the difference between the maximum value and the minimum value of the spectral distribution of the transmittance is 12.5% or more. Therefore, no rainbow unevenness is observed when the inclination angle from the normal direction of the first high retardation layer 232 is within 35 °. That is, from Table 6, the slow axis direction of the first high retardation layer 232 and the transmission of the two

polarizing plates

271 and 272 between the two

polarizing plates

271 and 272 in which the first high retardation layer 232 is disposed in cross nicol A wavelength range in which the two

polarizing plates

271 and 272 are transmitted in the direction inclined 45 ° from the normal direction of the first high retardation layer 232 in a state where the axial direction is disposed at an angle of 40 ° to 50 °. The difference between the maximum value and the minimum value of the spectral distribution of the light transmittance of 550 nm to 650 nm is preferably 10% or more, preferably a direction inclined 35 ° from the normal direction of the first high retardation layer 232 The difference between the maximum value and the minimum value of the spectral distribution of the transmittance of light in the wavelength range of 550 nm to 650 nm incident on the high retardation layer transmitted through By it it is understood that it can effectively suppress the occurrence of rainbow unevenness.

In the measurement of the spectral distribution of the light transmittance in each wavelength range shown in FIGS. 18 to 20, CWQ manufactured by Nitto Denko Corporation was used as the two

polarizing plates

271 and 272.

As described above, the light control member 220 according to the third embodiment includes the first transparent support 230 and the light control unit 250 supported by the first transparent support 230, and the light control unit 250 includes the light control unit 250. The visible light transmittance can be adjusted by electronic control, and the first transparent support 230 includes a first base layer 231 having optical anisotropy and a first high retardation laminated on the first base layer 231. And the first high retardation layer 232 has a retardation of 4000 nm or more. According to such a light control member 220, since the retardation of the first transparent support 230 is sufficiently large, the change in visible light transmittance for each wavelength with respect to the change in retardation is large, and light of various wavelengths is transmitted. The transmitted light is mixed and becomes easy to be recognized. For this reason, even if the visible light transmittance fluctuates due to the variation of retardation, it becomes difficult to visually recognize a color that may become rainbow unevenness. That is, it is possible to suppress the occurrence of rainbow unevenness caused by the variation in retardation of the first base material layer 231 in the light control member 220.

Further, in the light control member 220 of the third embodiment, the slow axis direction of the first high retardation layer 232 between the two

polarizing plates

271 and 272 in which the first high retardation layer 232 is disposed in cross nicol Two polarizations in the direction inclined 45 ° from the normal direction of the first high retardation layer 232 in a state where the transmission axis directions of the two

polarizing plates

271 and 272 form an angle of 40 ° to 50 °. The difference between the maximum value and the minimum value of the spectral distribution of the transmittance [%] of light in the wavelength range of 550 nm to 650 nm transmitted through the

plates

271 and 272 is 10 [%] or more. According to such a light control member 220, since the first high retardation layer 232 has a sufficiently large retardation, the variation of the visible light transmittance for each wavelength of the transmitted light becomes large. The difference in magnitude between the maximum value and the minimum value of the transmittance occurs in the above, and light of various wavelengths is easily transmitted. As a result, it is difficult to visually recognize the color of the transmitted light. Therefore, even in the direction inclined 45 ° from the normal direction of the first transparent support 230, it is difficult to observe rainbow unevenness.

Furthermore, in the light control member 220 according to the third embodiment, the first high retardation layer in the first transparent support 230 between the two

polarizing plates

271 and 272 in which the first transparent support 230 is arranged in cross nicol. With the slow axis direction of 232 and the transmission axis directions of the two

polarizing plates

271 and 272 arranged at an angle of 40 ° to 50 °, the normal direction of the first transparent support 230 is 45 ° The difference between the maximum value and the minimum value of the spectral distribution of the transmittance [%] of light in the wavelength range of 550 nm to 650 nm transmitted through the two

polarizing plates

271 and 272 in the inclined direction is 10 [%] or more. According to such a light control member 220, since the first high retardation layer 232 of the first transparent support 230 has a sufficiently large retardation, the variation of the visible light transmittance for each wavelength of the transmitted light becomes large. Therefore, in the wavelength range of visible light, a difference of a sufficient magnitude occurs between the maximum value and the minimum value of the transmittance, and light of various wavelengths is easily transmitted. As a result, it is difficult to visually recognize the color of the transmitted light. Therefore, even in the direction inclined 45 ° from the normal direction of the first transparent support 230, it is difficult to observe rainbow unevenness.

In the light control member 220 of the third embodiment, the first transparent support 230 is provided at a position separated from the light control unit 250 from the first base layer 231 and the first high retardation layer 232. It further has one functional layer 233, and the first functional layer 233 has at least one of an antireflection function and an antiglare function. According to such a light control member 220, the light control member 220 can be effectively provided with a reflection preventing function and an antiglare function.

Note that various changes can be made to the third embodiment described above.

For example, the second transparent support 240 may further have a second high retardation layer laminated to the second base layer 241. When the user of the light control member 220 uses, for example, polarized sunglasses, the retardation of the second transparent support 240 to be disposed between the second polarizing plate 252 of the light control unit 250 and the polarized sunglasses Rainbow unevenness can be observed due to the variation of By providing the second high retardation layer on the second transparent support 240, the retardation of the second transparent support 240 can be increased. As a result, the occurrence of rainbow unevenness caused by the variation in retardation of the second base layer 241 can be suppressed in the same manner as the rainbow unevenness due to the variation in retardation of the first base layer 231 described above is suppressed. it can.

The second transparent support 240 may further have a second functional layer provided at a position farther from the light control unit 250 than the second base layer 241. Similar to the first functional layer 233, the second functional layer may have at least one of an antireflective function and an antiglare function.

In the third embodiment described above, as shown in FIG. 12, in the first transparent support 230, the first high retardation layer 232 is provided between the first base layer 231 and the first functional layer 233. It is done. However, the first base layer 231 may be provided between the first high retardation layer 232 and the first functional layer 233. That is, the first base material layer 231 and the first high retardation layer shown in FIG. 12 may be arranged in reverse. In any case, it is possible to suppress the occurrence of rainbow unevenness caused by the variation in retardation of the first base layer 231 in the light control member 220. Similarly, when the second transparent support 240 has the second high retardation layer, the second base layer 241 may be provided on the side closer to the second bonding layer 224 or the side closer to the second bonding layer 224 A second high retardation layer may be provided. In any case, it is possible to suppress the occurrence of rainbow unevenness caused by the variation in retardation of the second base material layer 241.

In the light control member 220 according to the third embodiment described above, the light control unit 250 is disposed between the first polarizing plate 251, the second polarizing plate 252, the first polarizing plate 251, and the second polarizing plate 252. Although the example which includes the liquid crystal unit 255 having been described is shown, the configuration of the light control unit 250 is not limited to this example. For example, the light control unit may include a plurality of liquid crystal units, an absorption-type polarizing plate provided corresponding to the liquid crystal unit, and a reflection-type polarizing plate disposed between two liquid crystal units. The absorption type polarizing plate transmits one polarization component of light and absorbs the other polarization component, similarly to the

polarization plates

251 and 252 in the third embodiment described above. The reflective polarizer transmits one polarization component of light and reflects the other polarization component. In this case, by only applying a voltage to each liquid crystal unit to change the polarization direction of light transmitted through the liquid crystal unit, it is only possible to control the transmission of light in the light control member (in other words, "light blocking"). It is also possible to control the reflection of light.

As an example, as shown in FIG. 21, a first absorption polarizing plate 351, a first liquid crystal unit 355, a reflection polarizing plate 354, a second absorption polarizing plate 352, and a second liquid crystal unit 356. The operation of the light control unit 350 in which the third absorption polarizing plate 353 and the third absorption polarizing plate 353 are stacked in this order will be described. In the example described here, the transmission axes of the first absorption polarizing plate 351 and the third absorption polarizing plate 353 are the same, and are orthogonal to the transmission axes of the reflection polarizing plate 354 and the second absorption polarizing plate 352. There is. A TN type liquid crystal is used for the first liquid crystal unit 355, and the polarization direction of transmitted light is rotated by 90 ° when no voltage is applied, and the transmitted light is transmitted when a voltage is applied. Do not change the polarization direction. The second liquid crystal unit 356 uses a VA type liquid crystal, and does not change the polarization direction of the transmitted light when no voltage is applied, and the liquid crystal falls when the voltage is applied. The birefringence of the second liquid crystal unit 356 is changed to transmit light while changing the polarization direction by 90 °.

First, the light L7 incident on the light adjustment unit 350 from the first absorption polarizing plate 351 side will be described. When a voltage is applied to the first liquid crystal unit 355, the light L7 is transmitted through the first liquid crystal unit 355, reflected by the reflective polarizing plate 354 and transmitted again through the first liquid crystal unit 355, The light is emitted from the absorption polarizing plate 351. That is, the light L7 incident from the first absorption polarizing plate 351 side is reflected. When no voltage is applied to the first liquid crystal unit 355 and the second liquid crystal unit 356, the light L7 rotates the polarization direction by the first liquid crystal unit 355, and the reflective polarizing plate 354 and the second absorbing polarizing plate 352 To Penetrate. Thereafter, the light passes through the second liquid crystal unit 356 but is absorbed by the third absorption polarizing plate 353. That is, the light L7 incident from the first absorption polarizing plate 351 side is blocked. When a voltage is not applied to the first liquid crystal unit 355 but a voltage is applied to the second liquid crystal unit 356, the light L7 rotates its polarization direction by the first liquid crystal unit 355, and the reflective polarizer 354 And the second absorption polarizing plate 352. Thereafter, the polarization direction is changed by the second liquid crystal unit 356, and the third absorption polarizing plate 353 transmits and emits. That is, the light L7 incident from the first absorption polarizing plate 351 side passes through the light control unit 350.

Next, the light L8 incident on the light adjustment unit 350 from the third absorption polarizing plate 353 side will be described. When a voltage is not applied to the second liquid crystal unit 356, the light L8 is transmitted through the second liquid crystal unit 356 and absorbed by the second absorption type polarizing plate 352. That is, the light L8 incident from the third absorption polarizing plate 353 side is blocked. When a voltage is applied to the second liquid crystal unit 356 and the first liquid crystal unit 355, the light L8 changes the polarization direction by the second liquid crystal unit 356, and the second absorption polarizing plate 352 and the reflection polarizing plate 354 are changed. To Penetrate. Thereafter, the light passes through the first liquid crystal unit 355 but is absorbed by the first absorption type polarizing plate 351. That is, the light L8 incident from the third absorption polarizing plate 353 side is blocked. When a voltage is applied to the second liquid crystal unit 356 but no voltage is applied to the first liquid crystal unit 355, the light L8 changes the polarization direction by the second liquid crystal unit 356, and the second absorption type polarized light The light passes through the plate 352 and the reflective polarizing plate 354. After that, the polarization direction is rotated by the first liquid crystal unit 355, and the first absorption type polarizing plate 351 is transmitted and emitted. That is, the light L 8 incident from the third absorption polarizing plate 353 side passes through the light control unit 350. As described above, by controlling the application of the voltage to each liquid crystal unit, it is possible to appropriately switch transmission, shielding, and reflection of light incident on the light control member.

As another example, as shown in FIG. 22, a first absorption polarizing plate 451, a first liquid crystal unit 455, a reflection polarizing plate 454, a second liquid crystal unit 456, and a second absorption polarization. The operation of the light control unit 450 in which the plate 452 and the plate 452 are stacked in this order will be described. In the example described here, the transmission axes of the first absorption polarizing plate 451 and the second absorption polarizing plate 452 are the same, and are orthogonal to the transmission axis of the reflection polarizing plate 454. Similar to the example shown in FIG. 21, a TN type liquid crystal is used for the first liquid crystal unit 455, and a VA type liquid crystal is used for the second liquid crystal unit 456.

First, the light L9 incident on the light adjustment unit 450 from the first absorption polarizing plate 451 side will be described. When a voltage is applied to the first liquid crystal unit 455, the light L9 is transmitted through the first liquid crystal unit 455, reflected by the reflective polarizer 454, and transmitted again through the first liquid crystal unit 455, The light is emitted from the absorption polarizing plate 451. That is, the light L9 incident from the first absorption polarizing plate 451 side is reflected. When a voltage is not applied to the first liquid crystal unit 455 and the second liquid crystal unit 456, the light L 9 rotates the polarization direction by the first liquid crystal unit 455, and transmits the light of the reflective polarizer 454. Thereafter, the light passes through the second liquid crystal unit 456 but is absorbed by the second absorption type polarizing plate 452. That is, the light L9 incident from the first absorption polarizing plate 451 side is blocked. When a voltage is not applied to the first liquid crystal unit 455 but a voltage is applied to the second liquid crystal unit 456, the light L 9 rotates its polarization direction by the first liquid crystal unit 455, and the reflective polarizer 454. Through. After that, the polarization direction is changed by the second liquid crystal unit 456, and the second absorption type polarizing plate 452 transmits and emits. That is, the light L 9 incident from the first absorption type polarizing plate 451 is transmitted through the light control unit 450.

Next, the light L10 that has entered the light adjustment unit 450 from the second absorption polarizing plate 452 side will be described. When a voltage is not applied to the second liquid crystal unit 456, the light L10 is transmitted through the second liquid crystal unit 456, reflected by the reflective polarizing plate 454, transmitted again through the second liquid crystal unit 456, and then subjected to the second absorption. The light is emitted from the polarizing plate 452. That is, the light L10 incident from the second absorption polarizing plate 452 side is reflected. When a voltage is applied to the second liquid crystal unit 456 and the first liquid crystal unit 455, the light L 10 changes the polarization direction by the second liquid crystal unit 456, and passes through the reflective polarizing plate 454. Thereafter, the light passes through the first liquid crystal unit 455 but is absorbed by the first absorption type polarizing plate 451. That is, the light L10 incident from the second absorption polarizing plate 452 side is blocked. When a voltage is applied to the second liquid crystal unit 456 but no voltage is applied to the first liquid crystal unit 455, the light L 10 changes the polarization direction by the second liquid crystal unit 456, and the reflective polarizer 454. Through. Thereafter, the polarization direction is rotated by the first liquid crystal unit 455, and the light is transmitted through the first absorption polarizing plate 451 and is emitted. That is, the light L10 incident from the second absorption polarizing plate 452 side passes through the light control unit 450. As described above, by controlling the application of the voltage to each liquid crystal unit, it is possible to appropriately switch transmission, shielding, and reflection of light incident on the light control member.

According to the light control unit 350 of the configuration of the example shown in FIG. 21, each function of transmission, light shielding and reflection by the light control unit 350 can be more reliably exhibited. For example, when controlling the application of voltage to each liquid crystal unit to block light by the light control unit 350, the light transmittance of the light control unit 350 can be further lowered. On the other hand, according to the light adjustment unit 450 of the configuration of the example shown in FIG. 22, each function of transmission, light shielding and reflection by the light adjustment unit 450 can be appropriately switched with a simple configuration.

In the light control member 220 according to the third embodiment described above, the first transparent support 230 and the second transparent support 240 are stacked on both sides of the light control unit 250, but only on one side of the light control unit 250. A transparent support may be laminated. That is, for example, only the first transparent support 230 may be stacked on the light control unit 250.

In the third embodiment described above, the light control member 220 receives power supply from the outside, but a solar cell (not shown) is provided on a part of the light control member 220, and this solar cell May be configured to supply power. Furthermore, the irradiation light amount may be determined based on the output of the solar cell, and the transmittance may be automatically controlled accordingly.

Although the example in which the light control member 220 is adopted for the sun visor 10 is used in the above description, the application of the light control member 220 is not limited to the sun visor. As an example of another application, it is possible to adopt to the window part of a car, such as a side window or a sunroof of a car, or a train or an aircraft. Furthermore, it is also possible to adopt it to the window part of a building.

Claims

A pair of transparent substrates,
A light control cell disposed between the pair of transparent substrates;
It comprises: two bonding layers disposed between the transparent base and the light control cell and bonding the transparent base and the light control cell;
The light control cell can adjust the visible light transmittance by electronic control,
The storage modulus of the bonding layer at 1 ℃ above 30 ° C. or less, 6 × is 10 6 Pa or less, the light adjusting member.
The light control member according to claim 1, wherein the storage elastic modulus of the bonding layer is 1.4 × 10 6 Pa or less at 1 ° C. or more and 30 ° C. or less.
The light control member according to claim 1, wherein a thickness of at least one of the bonding layers is 50 μm or more.
The light control member according to claim 3, wherein the storage elastic modulus of the bonding layer is 3 × 10 4 Pa or more at 1 ° C. or more and 30 ° C. or less.
The light control member according to claim 4, wherein the storage elastic modulus of the bonding layer is 1 × 10 5 Pa or more at 1 ° C. or more and 30 ° C. or less.
The light control member according to claim 4 or 5, further comprising an easy adhesion layer disposed between the transparent substrate and the bonding layer.
The light control member according to any one of claims 4 to 6, further comprising a barrier layer disposed between the transparent substrate and the bonding layer.
The light control member according to any one of claims 1 to 7, further comprising an antireflective layer on the side of the transparent substrate opposite to the side on which the bonding layer is disposed.
A transparent substrate,
A light control cell laminated on the transparent substrate,
The light control cell can adjust the visible light transmittance by electronic control,
The light control member whose difference of the maximum value and minimum value of the retardation in the area | region which the said light control cell of the said transparent base material has overlapped is 100 nm or less.
The transparent substrate comprises polycarbonate,
The light control member according to claim 9, wherein an average value of retardation in a region where the light control cells of the transparent base material overlap is 2000 nm or more.
The transparent substrate comprises polycarbonate,
The light control member according to claim 9, wherein an average value of retardation in a region where the light control cells of the transparent base material overlap is 400 nm or less.
The melt volume flow rate of the transparent substrate is less 10 cm 3/10 min, the light adjusting member according to any one of claims 9 to 11.
The transparent substrate includes a curved surface,
The light control member according to any one of claims 9 to 11, wherein a curvature radius of the curved surface of the transparent substrate is 10 cm or more.
A transparent support,
A light control unit supported by the transparent support;
The light control unit can adjust the visible light transmittance by electronic control,
The transparent support has a base layer having optical anisotropy, and a high retardation layer laminated on the base layer,
The light control member whose retardation of the said high retardation layer is 4000 nm or more.
The high retardation layer is disposed so that the slow axis direction of the high retardation layer and the transmission axis direction of the two polarizing plates form an angle of 40 ° or more and 50 ° or less between the two polarizing plates disposed in cross nicol Maximum and minimum values of the spectral distribution [%] of light having a wavelength of 550 nm or more and 650 nm or less that transmits the two polarizing plates in the direction inclined 45 ° from the normal direction of the high retardation layer The light control member according to claim 14, wherein the difference between and is 10% or more.
An angle between the slow axis direction of the high retardation layer in the transparent support and the transmission axis direction of the two polarizing plates in the transparent support between 40 ° and 50 ° between two polarizing plates arranged in cross nicol on the transparent support Wavelength of light transmitted through the two polarizing plates in a direction inclined 45 ° from the normal direction of the transparent support in the state of being arranged in a spectral distribution [%] of light having a wavelength of 550 nm or more and 650 nm or less The light adjusting member according to claim 14, wherein the difference between the maximum value and the minimum value is 10% or more.
The transparent support further includes a functional layer provided at a position separated from the light control unit from the base layer and the high retardation layer,
The light control member according to any one of claims 14 to 16, wherein the functional layer has at least one of an antireflective function and an antiglare function.
A sun visor comprising the light control member according to any one of claims 1 to 17.
A mobile comprising the visor according to claim 18.