JP2020160097A - Optical device - Google Patents

Abstract

To provide an optical device having excellent light distribution performance.SOLUTION: The optical device comprises: a light-transmissive first substrate 10; a light-transmissive second substrate 20 opposed to the first substrate 10; a first electrode 30 arranged on the second substrate 20 side of the first substrate 10; a concavoconvex structure 50 arranged on the second substrate 20 side of the first electrode 30; a second electrode 40 arranged on the first substrate 10 side of the second substrate 20; and a refractive index variable layer 60 arranged between the concavoconvex structure 50 and the second electrode 40, and having a refractive index that changes in accordance with a voltage applied between the first electrode 30 and the second electrode 40. The refractive index variable layer 60 includes: an insulating liquid 61; and charged nanoparticles 62 included in the insulating liquid 61. The refractive index of the nanoparticles 62 is higher than the refractive index of the insulating liquid 61.SELECTED DRAWING: Figure 2

Description

The present invention relates to an optical device, and more particularly to an optical device capable of distributing incident light.

Conventionally, as an optical device, a light distribution device capable of distributing incident light has been proposed. Such optical devices are used for windows of buildings, cars, and the like. For example, by installing an optical device in a window of a building, it is possible to change the traveling direction of external light such as sunlight incident from the outside and introduce the outside light toward the ceiling of the room (for example, Patent Document). 1, 2).

As a light distribution device of this type, a device using a liquid crystal is known. For example, Patent Document 3 discloses a liquid crystal optical element including a pair of transparent substrates, a pair of transparent electrodes arranged inside the pair of transparent substrates, and a liquid crystal layer arranged between the pair of transparent electrodes. Has been done. In a light distribution device using a liquid crystal, the traveling direction of light incident on the light distribution device is changed by changing the orientation state of the liquid crystal molecules in the liquid crystal layer according to the voltage applied to the pair of transparent electrodes.

Japanese Unexamined Patent Publication No. 2012-259951 International Publication No. 2015/056736 Japanese Unexamined Patent Publication No. 2012-173534

However, a light distribution device using a liquid crystal cannot obtain sufficient light distribution performance.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an optical device having excellent light distribution performance.

In order to achieve the above object, one aspect of the first optical device according to the present invention is a light-transmitting first substrate and a light-transmitting second substrate arranged to face the first substrate. A substrate, a first electrode arranged on the second substrate side of the first substrate, a concave-convex structure arranged on the second substrate side of the first electrode, and the first substrate side of the second substrate. A refractive index is arranged between the concave-convex structure and the second electrode, and the refractive index changes according to the voltage applied between the first electrode and the second electrode. A variable index layer is provided, and the variable refractive index layer has an insulating liquid and charged nanoparticles dispersed in the insulating liquid, and the refractive index of the nanoparticles is the refractive index of the insulating liquid. Higher than the rate.

Further, one aspect of the second optical device according to the present invention is an optical device that controls incident light, that is, a first substrate having light transmission and light arranged to face the first substrate. A second substrate having transparency, a first electrode arranged on the second substrate side of the first substrate, an uneven structure arranged on the second substrate side of the first electrode, and the second substrate. The second electrode arranged on the first substrate side of the above, and the nanoparticles arranged between the uneven structure and the second electrode and having an insulating liquid and charged nanoparticles dispersed in the insulating liquid. The optical device includes a dispersion layer, and controls the traveling direction of light incident on the optical device according to a voltage applied between the first electrode and the second electrode.

Further, one aspect of the third optical device according to the present invention includes a first substrate having light transmission, a second substrate having light transmission arranged opposite to the first substrate, and the first substrate. A first electrode arranged on the second substrate side of the substrate, a concave-convex structure arranged on the second substrate side of the first electrode, and a second arranged on the first substrate side of the second substrate. A nanoparticle dispersion layer having an electrode and a nanoparticle dispersion layer having an insulating liquid and charged nanoparticles dispersed in the insulating liquid, which is arranged between the concave-convex structure and the second electrode, is provided, and the first electrode and the second electrode are provided. The particle distribution of the nanoparticles in the nanoparticle dispersion layer changes according to the voltage applied between the second electrode and the second electrode.

According to the present invention, an optical device having excellent light distribution performance can be realized.

It is sectional drawing of the optical device which concerns on embodiment. It is an enlarged sectional view of the optical device which concerns on embodiment. It is a figure for demonstrating the first optical action of the optical device which concerns on embodiment. It is a figure for demonstrating the second optical action of the optical device which concerns on embodiment. It is a figure for demonstrating the third optical action of the optical device which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described. In addition, all of the embodiments described below show a preferable specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions of the components, connection forms, and the like shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components.

Each figure is a schematic view and is not necessarily exactly illustrated. Therefore, the scales and the like do not always match in each figure. In each figure, substantially the same configuration is designated by the same reference numerals, and duplicate description will be omitted or simplified.

Further, in the present specification and the drawings, the X-axis, the Y-axis, and the Z-axis represent the three axes of the three-dimensional Cartesian coordinate system. In the present embodiment, the Z-axis direction is the vertical direction and is perpendicular to the Z-axis. (Direction parallel to the XY plane) is the horizontal direction. The X-axis and the Y-axis are orthogonal to each other and both are orthogonal to the Z-axis. The positive direction in the Z-axis direction is vertically downward. Further, in the present specification, the "thickness direction" means the thickness direction of the optical device, and is a direction perpendicular to the main surfaces of the first substrate 10 and the second substrate 20 (in the present embodiment, the Y-axis direction). That is.

(Embodiment)
First, the configuration of the optical device 1 according to the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the optical device 1 according to the embodiment. FIG. 2 is an enlarged cross-sectional view of the optical device 1, and shows an enlarged view of a region II surrounded by a broken line in FIG.

The optical device 1 is an optical control device that controls light incident on the optical device 1. Specifically, the optical device 1 controls the traveling direction of the light incident on the optical device 1. In the present embodiment, the optical device 1 is a light distribution device capable of changing the traveling direction of incident light (for example, distributing light) to emit light.

As shown in FIGS. 1 and 2, the optical device 1 includes a first substrate 10, a second substrate 20, a first electrode 30, a second electrode 40, an uneven structure 50, and a variable refractive index layer 60. To be equipped.

In the optical device 1, the first electrode 30, the concave-convex structure 50, the refractive index variable layer 60, and the second electrode 40 are arranged between the pair of the first substrate 10 and the second substrate 20 in this order along the thickness direction. It has a structure of

Further, as shown in FIG. 1, in the optical device 1, the first substrate 10, the first electrode 30, and the concave-convex structure 50 constitute the first laminated substrate 100, and the second substrate 20 and the second electrode 40 are the first. The two laminated substrates 200 are configured.

The first laminated substrate 100 and the second laminated substrate 200 are arranged so as to face each other with a gap, and the entire circumference of the outer peripheral end portion is sealed. As a result, the variable refractive index layer 60 filled between the first laminated substrate 100 and the second laminated substrate 200 can be confined. For example, a sealing member such as an adhesive is formed on the inner surface of the first laminated substrate 100 and the second laminated substrate 200 in a frame shape, or the first substrate 10 and the second substrate 20 are welded by a laser. By doing so, the outer peripheral ends of the first laminated substrate 100 and the second laminated substrate 200 can be sealed.

Hereinafter, each component of the optical device 1 will be described in detail with reference to FIGS. 1 and 2.

[First board, second board]
As shown in FIGS. 1 and 2, the first substrate 10 is the base material of the first laminated substrate 100, and the second substrate 20 is the base material of the second laminated substrate 200.

The first substrate 10 and the second substrate 20 are light-transmitting substrates (translucent substrate). The first substrate 10 and the second substrate 20 are preferably transparent transparent substrates.

As the first substrate 10 and the second substrate 20, for example, a resin substrate made of a resin material or a glass substrate made of a glass material can be used. Examples of the material of the resin substrate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), acrylic and epoxy. Examples of the material of the glass substrate include soda glass, non-alkali glass, high refractive index glass and the like. The resin substrate has an advantage that it is less scattered at the time of destruction. On the other hand, the glass substrate has the advantages of high light transmittance and low moisture transmittance.

The first substrate 10 and the second substrate 20 may be made of the same material or may be made of different materials, but it is better that they are made of the same material. Further, the first substrate 10 and the second substrate 20 are not limited to the rigid substrate, and may be a flexible substrate or a film substrate. In the present embodiment, a transparent resin substrate (PET substrate) made of PET is used as the first substrate 10 and the second substrate 20.

The thickness of the first substrate 10 and the second substrate 20 is, for example, 5 μm to 3 mm, but is not limited to this. In the present embodiment, the thickness of the first substrate 10 and the second substrate 20 are both 50 μm.

Further, the shape of the first substrate 10 and the second substrate 20 in a plan view is, for example, a square or a rectangular rectangle, but the shape is not limited to this, and may be a polygon other than a circle or a quadrangle. Shape can be adopted.

[First electrode, second electrode]
As shown in FIGS. 1 and 2, the first electrode 30 and the second electrode 40 are electrically paired and are configured to be able to apply an electric field to the variable refractive index layer 60. Further, the first electrode 30 and the second electrode 40 are arranged in pairs and are arranged so as to face each other.

The first electrode 30 is arranged on the second substrate 20 side of the first substrate 10. Further, the second electrode 40 is arranged on the first substrate 10 side of the second substrate 20. Specifically, the first electrode 30 is formed on the main surface of the first substrate 10 on the second substrate 20 side, and the second electrode 40 is formed on the main surface of the second substrate 20 on the first substrate 10 side. It is formed.

Further, in the present embodiment, the pair of the first electrode 30 and the second electrode 40 are sandwiched between the first substrate 10 and the second substrate 20 so as to sandwich at least the concave-convex structure 50 and the variable refractive index layer 60. Have been placed. Specifically, the first electrode 30 is arranged between the first substrate 10 and the concave-convex structure 50, and the second electrode 40 is arranged between the second substrate 20 and the variable refractive index layer 60. ing.

The thickness of each of the first electrode 30 and the second electrode 40 is, for example, 5 nm to 2 μm, but is not limited thereto. In the present embodiment, the thickness of each of the first electrode 30 and the second electrode 40 is 100 nm.

Further, the shape of the first electrode 30 and the second electrode 40 in a plan view is, for example, a square or a rectangular rectangle like the first substrate 10 and the second substrate 20, but is not limited thereto. In the present embodiment, the first electrode 30 and the second electrode 40 are solid electrodes having a rectangular shape in a plan view formed on substantially the entire surface of each of the surfaces of the first substrate 10 and the second substrate 20.

The first electrode 30 and the second electrode 40 are electrodes having translucency and transmit incident light. The first electrode 30 and the second electrode 40 are transparent electrodes made of, for example, a transparent conductive layer. As the material of the transparent conductive layer, a conductor-containing resin composed of a transparent metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), and a resin containing a conductor such as silver nanowires or conductive particles. Alternatively, a metal thin film such as a silver thin film can be used. The first electrode 30 and the second electrode 40 may have a single-layer structure thereof or a laminated structure thereof (for example, a laminated structure of a transparent metal oxide and a metal thin film).

The first electrode 30 and the second electrode 40 are configured to enable electrical connection with an external power source. For example, each of the first electrode 30 and the second electrode 40 is drawn out to the outside of the sealing resin that seals the variable refractive index layer 60, and the drawn out portions are used as electrode terminals for connecting to an external power source. May be good.

[Concave and convex structure]
As shown in FIGS. 1 and 2, the concavo-convex structure 50 is a concavo-convex layer having a concavo-convex surface, and has a configuration in which a plurality of micro-order-sized or nano-order-sized convex portions 51 are arranged.

The uneven structure 50 is arranged on the second substrate 20 side of the first substrate 10. In the present embodiment, the concave-convex structure 50 is arranged on the second substrate 20 side of the first electrode 30. Specifically, the concave-convex structure 50 is provided on the main surface of the first electrode 30 on the second substrate 20 side.

In the present embodiment, the concave-convex structure 50 is provided on the first electrode 30 so that the plurality of convex portions 51 project toward the variable refractive index layer 60 side. In this case, an adhesion layer may be formed between the first electrode 30 and the uneven structure 50. The surface of the concave-convex structure 50 on the first electrode 30 side (the surface of the convex portion 51 on the first electrode 30 side) is a flat surface.

Further, the plurality of convex portions 51 are formed in a striped shape. Specifically, each of the plurality of convex portions 51 has a triangular cross-sectional shape and is a long substantially triangular prism shape extending in the X-axis direction, and is arranged at equal intervals along the Z-axis direction. Further, all the convex portions 51 have the same shape, but the present invention is not limited to this.

Each convex portion 51 has, for example, a height of 100 nm or more and 100 μm or less, and an aspect ratio (height / lower base) of about 1 to 10, but is not limited to this. As an example, each convex portion 51 has a height of about 10 μm, a lower base of about 5 μm, and an upper base of about 2 μm.

Further, the distance between the two convex portions 51 adjacent to each other in the Z-axis direction is, for example, 0 or more and 100 mm or less. That is, the two convex portions 51 adjacent to each other in the Z-axis direction may be arranged with a predetermined interval without contacting the bottoms, or may be arranged with the bottoms in contact with each other (at zero interval). However, the distance between the two convex portions 51 adjacent to each other in the Z-axis direction is preferably equal to or less than the base of the convex portions 51. As an example, in the case of the convex portion 51 of the above size (height 10 μm, base 5 μm), the distance between two adjacent convex portions 51 is about 2 μm.

Each of the plurality of protrusions 51 has a pair of side surfaces. In the present embodiment, the cross-sectional shape of each convex portion 51 is a tapered shape that tapers along the direction (Y-axis minus direction) from the second substrate 20 to the first substrate 10. Therefore, each of the pair of side surfaces of each convex portion 51 is an inclined surface that is inclined at a predetermined inclination angle with respect to the thickness direction, and the distance between the pair of side surfaces in each convex portion 51 (width of the convex portion 51). Is gradually getting smaller from the second substrate 20 toward the first substrate 10. The inclination angles of the two sides of each convex portion 51 may be the same or different. In the present embodiment, the cross-sectional shape of each convex portion 51 is an isosceles triangle, and the inclination angles (base angles) of the two side surfaces of each convex portion 51 are the same.

The pair of side surfaces of each convex portion 51 is a surface in contact with the variable refractive index layer 60, and the light incident from the first substrate 10 receives an optical action on the pair of side surfaces of the convex portion 51.

Specifically, on one side surface (lower side surface in the present embodiment) of the pair of side surfaces of the convex portion 51, the light incident from the first substrate 10 is the convex portion 51 and the refractive index variable layer 60. Depending on the difference in refractive index with, it may be refracted and transmitted, or it may be transmitted as it is without refraction.

Further, on the other side surface (upper side surface in the present embodiment) of the pair of side surfaces of the convex portion 51, the light incident from the first substrate 10 has the refractive index of the convex portion 51 and the refractive index variable layer 60. Depending on the difference, it may be refracted and transmitted, it may be transmitted as it is without refraction, or it may be totally reflected. That is, the upper side surface of the convex portion 51 can be a total reflection surface depending on the difference in refractive index between the convex portion 51 and the variable refractive index layer 60 and the incident angle of light.

As the material of the concave-convex structure 50 (convex portion 51), for example, a translucent resin material such as an acrylic resin, an epoxy resin, or a silicone resin can be used. The uneven structure 50 can be formed by, for example, laser processing or imprinting. In the present embodiment, the uneven structure 50 is formed by using an acrylic resin having a refractive index of about 1.5.

The concave-convex structure 50 may be made of only an insulating resin material as long as an electric field can be applied to the variable refractive index layer 60 by the first electrode 30 and the second electrode 40, but it is conductive. May have. In this case, as the material of the uneven structure 50, a conductive polymer such as PEDOT, a resin containing a conductor (conductor-containing resin), or the like can be used.

[Variable refractive index layer]
As shown in FIGS. 1 and 2, the refractive index variable layer 60 has an insulating liquid 61 and nanoparticles 62 contained in the insulating liquid 61. The variable refractive index layer 60 is a nanoparticle dispersion layer in which innumerable nanoparticles 62 are dispersed in an insulating liquid 61.

The insulating liquid 61 is a transparent liquid having an insulating property, and is a solvent that serves as a dispersion medium in which nanoparticles 62 are dispersed as a dispersoid. As the insulating liquid 61, for example, a liquid having a refractive index (solvent refractive index) of about 1.3 to about 1.6 can be used. In this embodiment, an insulating liquid 61 having a refractive index of about 1.5 is used.

The kinematic viscosity of the insulating liquid 61 is preferably about 100 mm ² / s. Further, the insulating liquid 61 is preferably having a low dielectric constant (dielectric constant of the concave-convex structure 50 or less), non-flammable (high flash point having a flash point of 250 ° C. or higher), and low volatility. Specifically, the insulating liquid 61 is a hydrocarbon (aliphatic hydrocarbon, naphtha, other petroleum-based solvent, etc.), a low molecular weight halogen-containing polymer, or a mixture thereof. As an example, the insulating liquid 61 is a halogenated carbon hydrogen such as fluorocarbon hydrogen. As the insulating fluid 61, silicone oil or the like can also be used.

A plurality of nanoparticles 62 are dispersed in the insulating liquid 61. The nanoparticles 62 are fine particles having a particle size of nanoorder size. Specifically, assuming that the wavelength of the incident light is λ, the particle size of the nanoparticles 62 is preferably λ / 4 or less. By setting the particle size of the nanoparticles 62 to λ / 4 or less, light scattering in the nanoparticles 62 can be reduced, and an average refractive index between the nanoparticles 62 and the insulating liquid 61 can be obtained. The smaller the particle size of the nanoparticles 62, the better, preferably 100 nm or less, and more preferably several nm to several tens of nm.

The nanoparticles 62 are preferably made of a high refractive index material. Specifically, the refractive index of the nanoparticles 62 is higher than that of the insulating liquid 61. In the present embodiment, the refractive index of the nanoparticles 62 is higher than the refractive index of the concave-convex structure 50.

As the nanoparticles 62, metal oxide fine particles can be used. Further, the nanoparticles 62 are preferably made of a material having a high transmittance. In the present embodiment, transparent zirconia particles having a refractive index of 2.1 and composed of zirconium oxide (ZrO ₂ ) are used as the nanoparticles 62. The nanoparticles 62 are not limited to zirconium oxide, and may be made of titanium oxide or the like.

Further, the nanoparticles 62 are charged particles that are charged. For example, by modifying the surface of the nanoparticles 62, the nanoparticles 62 can be positively (plus) or negatively (minus) charged. In the present embodiment, the nanoparticles 62 are positively charged.

In the variable refractive index layer 60 configured in this way, the charged nanoparticles 62 are dispersed throughout the insulating liquid 61. In the present embodiment, zirconia particles having a refractive index of 2.1 are used as the nanoparticles 62, and the nanoparticles 62 are dispersed in an insulating liquid 61 having a refractive index of about 1.5, and the refractive index is variable. The layer is 60.

Further, the refractive index (average refractive index) of the entire variable refractive index layer 60 is the same as the refractive index of the uneven structure 50 in a state where the nanoparticles 62 are uniformly dispersed in the variable refractive index layer 60 (insulating liquid 61). It's different. Specifically, the refractive index of the entire variable refractive index layer 60 is set to be higher than the refractive index of the concave-convex structure 50, which is about 1.6 in the present embodiment. The refractive index of the entire variable refractive index layer 60 can be changed by adjusting the concentration (amount) of the nanoparticles 62 dispersed in the insulating liquid 61. The details will be described later, but the amount of the nanoparticles 62 should be such that it is buried in the recesses of the concave-convex structure 50 (the region between the two adjacent convex portions 51). In this case, the concentration of the nanoparticles 62 with respect to the insulating liquid 61. Is about 10% to 30%.

The variable refractive index layer 60 is arranged between the concave-convex structure 50 and the second electrode 40. Specifically, the variable refractive index layer 60 is in contact with the uneven structure 50. That is, the contact surface of the variable refractive index layer 60 with the uneven surface of the concave-convex structure 50 is the interface between the variable refractive index layer 60 and the uneven surface of the concave-convex structure 50. Although the variable refractive index layer 60 is also in contact with the second electrode 40, another layer (film) may be interposed between the variable refractive index layer 60 and the second electrode 40.

Further, the refractive index of the variable refractive index layer 60 changes according to the voltage applied between the first electrode 30 and the second electrode 40. Specifically, the variable refractive index layer 60 is arranged between the first electrode 30 and the second electrode 40, and a voltage is applied between the first electrode 30 and the second electrode 40. An electric field is applied to the variable refractive index layer 60. For example, a DC voltage is applied between the first electrode 30 and the second electrode 40.

Since the nanoparticles 62 dispersed in the insulating liquid 61 are charged, when an electric field is applied to the variable refractive index layer 60, the nanoparticles 62 travel in the insulating liquid 61 according to the electric field distribution and have insulating properties. It is unevenly distributed in the liquid 61. As a result, the particle distribution of the nanoparticles 62 in the variable refractive index layer 60 can be changed to give the concentration distribution of the nanoparticles 62 in the variable refractive index layer 60, so that the refractive index in the variable refractive index layer 60 can be provided. The distribution changes. That is, the refractive index of the variable refractive index layer 60 changes partially. As described above, the variable refractive index layer 60 functions mainly as a refractive index adjusting layer capable of adjusting the refractive index with respect to light in the visible light region.

The variable refractive index layer 60 configured in this way is arranged between the first laminated substrate 100 and the second laminated substrate 200. Specifically, the insulating liquid 61 in which the nanoparticles 62 are dispersed is sealed between the first laminated substrate 100 and the second laminated substrate 200.

The thickness of the variable refractive index layer 60 (that is, the gap between the first laminated substrate 100 and the second laminated substrate 200) is, for example, 1 μm to 100 μm, but is not limited to this. As an example, when the height of the convex portion 51 of the concave-convex structure 50 is 10 μm, the thickness of the refractive index variable layer 60 is, for example, 40 μm.

[Manufacturing method of optical device]
Next, a method of manufacturing the optical device 1 will be described with reference to FIGS. 1 and 2.

First, using, for example, a PET substrate as the first substrate 10, an ITO film is formed as the first electrode 30 on the PET substrate, and a plurality of acrylic resins (refractive index 1.5) are formed on the ITO film. The first laminated substrate 100 is manufactured by forming the concavo-convex structure 50 composed of the convex portions 51 by the imprint method.

Next, the second laminated substrate 200 is manufactured by forming the second electrode 40 made of an ITO film on the PET substrate using, for example, a PET substrate as the second substrate 20.

Next, between the first laminated substrate 100 and the second laminated substrate 200, an insulating liquid 61 in which nanoparticles 62 are dispersed is filled as a refractive index variable layer 60, and the first laminated substrate 100 and the second laminated substrate 200 are filled. The variable refractive index layer 60 is sealed between the first laminated substrate 100 and the second laminated substrate 200 by joining the outer peripheral portion with the laminated substrate 200.

In this way, the optical device 1 having the structure shown in FIG. 1 can be manufactured.

[Optical action of optical device]
Next, the optical action of the optical device 1 according to the embodiment will be described with reference to FIGS. 3A, 3B and 3C. FIG. 3A is a diagram for explaining the first optical action of the optical device 1 according to the embodiment, and FIG. 3B is a diagram for explaining the second optical action of the optical device 1, FIG. 3C. Is a diagram for explaining the third optical action of the optical device 1.

The optical device 1 can be realized as a window with a light distribution control function by installing it, for example, in a window of a building. The optical device 1 is attached to a window of a building via, for example, an adhesive layer. In this case, the optical device 1 is installed in the window so that the longitudinal direction of the convex portion 51 of the concave-convex structure 50 is the horizontal direction. For example, sunlight is incident on the optical device 1 installed in the window. In the present embodiment, since the optical device 1 is installed so that the first substrate 10 is located on the light incident side (outside of the building), the optical device 1 is the light (sunlight) incident from the first substrate 10. ) Can be transmitted from the second substrate 20 to the inside of the building (for example, indoors) of the optical device 1.

At this time, the light incident on the optical device 1 receives an optical action from the optical device 1 when passing through the optical device 1. Specifically, the optical action of the optical device 1 changes depending on the change in the refractive index of the variable refractive index layer 60. Therefore, the light incident on the optical device 1 is subjected to different optical actions depending on the refractive index of the variable refractive index layer 60, and the traveling direction is controlled according to the refractive index of the variable refractive index layer 60.

In the present embodiment, the optical device 1 can control the traveling direction of the light incident on the optical device 1 according to the voltage applied between the first electrode 30 and the second electrode 40. Specifically, the particle distribution of the nanoparticles 62 in the variable refractive index layer 60 (nanoparticle dispersion layer) changes according to the voltage applied between the first electrode 30 and the second electrode 40, whereby , The refractive index of the variable refractive index layer 60 is partially changed. As a result, the optical action of the optical device 1 changes. The optical device 1 in this embodiment has three optical actions. Hereinafter, the three optical actions of the optical device 1 will be described in detail.

First, the first optical action of the optical device 1 will be described with reference to FIG. 3A. When no potential is applied to the first electrode 30 and the second electrode 40, that is, when no voltage is applied between the first electrode 30 and the second electrode 40 (when no voltage is applied), optics. The device 1 enters the first optical mode and gives the first optical action to the incident light.

In the first optical mode, no electric field is applied to the variable refractive index layer 60, so that the nanoparticles 62 are dispersed throughout the insulating liquid 61 in the variable refractive index layer 60, as shown in FIG. 3A. .. At this time, in the present embodiment, as described above, the refractive index of the refractive index variable layer 60 in a state where the nanoparticles 62 are dispersed in the entire insulating liquid 61 is about 1.6. Further, the refractive index of the concave-convex structure 50 is about 1.5. Therefore, when no voltage is applied between the first electrode 30 and the second electrode 40 (in the case of the first optical mode), the refractive index of the entire variable refractive index layer 60 is higher than that of the concave-convex structure 50. It is high, and there is a difference in refractive index between the refractive index of the concave-convex structure 50 and the variable refractive index layer 60.

In this case, as shown in FIG. 3A, when light L1 is incident on the optical device 1 from an oblique direction, there is a difference in refractive index at the interface between the concave-convex structure 50 (convex portion 51) and the variable refractive index layer 60. The light L1 is refracted at the interface between the variable refractive index layer 60 and the lower side surface of the convex portion 51 and the variable refractive index layer 60, and then the upper side surface of the variable refractive index layer 60 and the convex portion 51 and the refractive index. It is totally reflected at the interface with the variable layer 60, the traveling direction is bent in the direction of rebound, and the light is emitted to the outside of the optical device 1. That is, the light L1 incident on the optical device 1 is distributed by the optical device 1.

In this way, when no voltage is applied between the first electrode 30 and the second electrode 40, the optical device 1 distributes the light incident on the first substrate 10 and transmits it through the second substrate 20. .. That is, the first optical mode is the first light distribution mode, and in the first optical mode, the optical device 1 is in the first light distribution state. In this case, the light incident on the first substrate 10 is reflected by the concave-convex structure 50 of the optical device 1 as described above, the traveling direction is changed, and the light is emitted from the second substrate 20.

Although details are not shown, there is a difference in refractive index between the members, such as the interface between the first substrate 10 and the first electrode 30, or the interface between the variable refractive index layer 60 and the second electrode 40. At the location, the light incident from the first substrate 10 will be refracted at the interface.

Next, the second optical action of the optical device 1 will be described with reference to FIG. 3B. When a potential is applied to the first electrode 30 and the second electrode 40, that is, when the first voltage is applied between the first electrode 30 and the second electrode 40 (when the first voltage is applied). The optical device 1 enters the second optical mode and gives a second optical action to the incident light. Specifically, a DC voltage is applied as the first voltage between the first electrode 30 and the second electrode 40. The first voltage (potential difference) applied between the first electrode 30 and the second electrode 40 is, for example, about several tens of volts.

In the second optical mode, an electric field is applied to the variable refractive index layer 60 by applying a DC voltage between the first electrode 30 and the second electrode 40. Therefore, in the variable refractive index layer 60, charged nanoparticles 62 runs through the insulating liquid 61 according to its electric field distribution. That is, the nanoparticles 62 are electrophoresed in the insulating liquid 61.

Specifically, in the second optical mode, a negative potential is applied to the first electrode 30 and a positive potential is applied to the second electrode 40, so that the positively charged nanoparticles 62 are the first electrode having a negative potential. It migrates toward 30, and is aggregated and unevenly distributed on the uneven structure 50 side in the variable refractive index layer 60. At this time, the nanoparticles 62 that migrate toward the first electrode 30 enter the recesses of the concave-convex structure 50, that is, the region between the two adjacent convex portions 51, and accumulate.

As described above, when the nanoparticles 62 are unevenly distributed on the uneven structure 50 side in the variable refractive index layer 60, the particle distribution of the nanoparticles 62 changes, and the refractive index distribution in the variable refractive index layer 60 becomes non-uniform. .. Specifically, in the variable refractive electrode layer 60, the nanoparticles 62 are gathered by the migration of the entire nanoparticles 62, and the first region 60a on the uneven structure 50 side where the concentration of the nanoparticles 62 is increased, and the nanoparticles. By the migration of the entire 62, the nanoparticles 62 disappeared and the second region 60b on the second electrode 40 side where the concentration of the nanoparticles 62 became low was generated, and the refractive index was generated in the first region 60a and the second region 60b. There is a difference.

In this case, since the refractive index of the nanoparticles 62 is higher than that of the insulating liquid 61, the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is the second refractive index of the variable refractive index layer 60. It is higher than the refractive index of the second region 60b on the electrode 40 side.

In the present embodiment, as described above, the variable refractive index layer 60 is formed by dispersing the nanoparticles 62 made of zirconia particles having a refractive index of 2.1 in an insulating liquid 61 having a refractive index of about 1.5. Since the refractive index of the entire variable refractive index layer 60 is about 1.6 when no voltage is applied, the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 when the first voltage is applied. The refractive index of is distributed in the thickness direction from about 1.8 to about 1.6, and the refractive index of the second region 60b on the second electrode 40 side of the variable refractive index layer 60 is about 1.6 to about 1.6 in the thickness direction. It is distributed at about 1.5.

As a result, as described above, the refractive index of the concave-convex structure 50 is about 1.5, so that in the case of the second optical mode (the first voltage is applied between the first electrode 30 and the second electrode 40). Between the refractive index of the concave-convex structure 50 (about 1.5) and the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 (about 1.6 to about 1.8). Causes a difference in refractive index. At this time, the difference in refractive index between the refractive index of the concave-convex structure 50 and the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is larger than that in the first optical mode.

In this case, as shown in FIG. 3B, when light L1 is incident on the optical device 1 from an oblique direction, there is a difference in refractive index at the interface between the concave-convex structure 50 (convex portion 51) and the variable refractive index layer 60. As in the first optical mode, the light L1 is refracted at the interface between the variable refractive index layer 60 and the lower side surface of the convex portion 51 and the variable refractive index layer 60, and then becomes the variable refractive index layer 60. Full reflection occurs at the interface between the upper side surface of the convex portion 51 and the variable refractive index layer 60, and the traveling direction is bent in the direction of rebound and emitted to the outside of the optical device 1. That is, the light L1 incident on the optical device 1 is distributed by the optical device 1.

However, in the second optical mode, the light is distributed at a different angle than in the first optical mode. Specifically, in the second optical mode, the light is distributed at a steeper angle than in the first optical mode. That is, the reflection angle when the light L1 incident on the optical device 1 is totally reflected on the side surface of the convex portion 51 is smaller in the second optical mode than in the first optical mode. As a result, the angle of rebound (light distribution angle) when the incident light L1 is totally reflected on the side surface of the convex portion 51 and rebounds upward is in the case of the second optical mode than in the case of the first optical mode. The emission angle when emitting from the second substrate 20 is larger in the second optical mode than in the first optical mode.

In this way, when the first voltage is applied between the first electrode 30 and the second electrode 40, the optical device 1 directs the light incident on the first substrate 10 between the first electrode 30 and the second electrode. Light is distributed at a steeper angle than when no voltage is applied to and from 40, and the second substrate 20 is transmitted. That is, the second optical mode is a light distribution mode similar to the first optical mode, but the second optical mode is a second light distribution mode in which light is distributed steeper than the first optical mode. In the two optical modes, the optical device 1 is in the second light distribution state. In the second optical mode, the light incident on the first substrate 10 is reflected by the concave-convex structure 50 of the optical device 1, the traveling direction is significantly changed, and the light is emitted from the second substrate 20.

Although details are not shown, even in the second optical mode, between each member, such as the interface between the first substrate 10 and the first electrode 30, or the interface between the variable refractive index layer 60 and the second electrode 40, etc. Where there is a difference in refractive index at the interface, the light incident from the first substrate 10 is refracted at the interface, as described above.

Next, the third optical action of the optical device 1 will be described with reference to FIG. 3C. When a potential different from that in the second optical mode is applied to the first electrode 30 and the second electrode 40, that is, a second voltage different from the first voltage is applied between the first electrode 30 and the second electrode 40. When a voltage is applied (when a second voltage is applied), the optical device 1 enters the third optical mode and gives a third optical action to the incident light. Specifically, a DC voltage that is opposite to the DC voltage in the second optical mode is applied as the second voltage between the first electrode 30 and the second electrode 40. The second voltage (potential difference) applied between the first electrode 30 and the second electrode 40 is, for example, about several tens of volts.

In the third optical mode, an electric field is applied to the refractive index variable layer 60 by applying a DC voltage between the first electrode 30 and the second electrode 40, so that the refractive index is variable as in the second optical mode. In layer 60, the charged nanoparticles 62 travel in the insulating liquid 61 according to their electric field distribution. That is, the nanoparticles 62 are electrophoresed in the insulating liquid 61.

However, in the third optical mode, unlike the second optical mode, a positive potential is applied to the first electrode 30 and a negative potential is applied to the second electrode 40, so that the positively charged nanoparticles 62 are the third. It travels toward the two electrodes 40, and is aggregated and unevenly distributed on the side of the second electrode 40 in the variable refractive index layer 60. At this time, the nanoparticles 62 that migrated toward the second electrode 40 are accumulated in layers on the surface of the second electrode 40.

As a result, the nanoparticles 62 gather in the second region 60b on the second electrode 40 side in the variable refractive index layer 60, and the concentration of the nanoparticles 62 increases. On the other hand, in the first region 60a on the concave-convex structure 50 side in the variable refractive index layer 60, the nanoparticles 62 disappear and the concentration of the nanoparticles 62 becomes low. As a result, in the variable refractive index layer 60, a difference in refractive index occurs between the first region 60a on the concave-convex structure 50 side and the second region 60b on the second electrode 40 side.

In this case, since the refractive index of the nanoparticles 62 is higher than that of the insulating liquid 61, the refractive index of the first region 60a on the concave-convex structure 50 side of the refractive index variable layer 60 in which the concentration of the nanoparticles 62 is low is , The concentration of the nanoparticles 62 is lower than the refractive index of the second region 60b on the second electrode 40 side of the variable refractive index layer 60. For example, the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is distributed in the thickness direction from about 1.5 to about 1.6, and the second electrode 40 side of the variable refractive index layer 60. The refractive index of the second region 60b is distributed in the thickness direction from about 1.6 to about 1.8.

Further, when the second voltage is applied, the refractive index in the vicinity of the concave-convex structure 50 in the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is substantially the same as the refractive index of the concave-convex structure 50. As a result, the difference in refractive index between the first region 60a on the uneven structure 50 side of the variable refractive index layer 60 and the uneven structure 50 (convex portion 51) is almost eliminated (refractive index difference Δn≈0).

In the present embodiment, as described above, the variable refractive index layer 60 is formed by dispersing the nanoparticles 62 made of zirconia particles having a refractive index of 2.1 in the insulating liquid 61 having a refractive index of about 1.5. Therefore, when the second voltage is applied, the refractive index in the vicinity of the concave-convex structure 50 in the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is about 1 which is substantially the same as the refractive index of the concave-convex structure 50. It becomes .5. Further, the refractive index in the vicinity of the second electrode 40 in the second region 60b on the second electrode 40 side of the variable refractive index layer 60 is about 1.8.

In this case, as shown in FIG. 3C, when light L1 is incident on the optical device 1 from an oblique direction, there is no difference in refractive index at the interface between the concave-convex structure 50 (convex portion 51) and the variable refractive index layer 60. The light L1 incident on the optical device 1 is not refracted at the interface between the variable refractive index layer 60 and the side surface of the convex portion 51, and the traveling direction does not change. Therefore, in the third optical mode, the light L1 incident on the optical device 1 travels straight inside the optical device 1 and is emitted to the outside of the optical device 1 without being bent in the traveling direction by the optical device 1.

In this way, when the second voltage is applied between the first electrode 30 and the second electrode 40, the optical device 1 advances the light incident on the first substrate 10 in a straight line to move the second substrate 20. Make it transparent. That is, the third optical mode is a transparent mode, and in the third optical mode, the optical device 1 is in a transparent state. In this case, the light incident on the first substrate 10 travels straight through without being distributed by the optical device 1 and is emitted from the second substrate 20.

In the third optical mode, the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 and the refractive index of the concave-convex structure 50 are substantially the same as the first region 60a of the variable refractive index layer 60. The difference in refractive index between the and the concave-convex structure 50 is 0.010 or less, more preferably 0.005 or less (Δn ≦ 0.005). When the difference in refractive index between the first region 60a of the variable refractive index layer 60 and the concave-convex structure 50 exceeds 0.005, light is scattered at the interface between the first region 60a of the variable refractive index layer 60 and the concave-convex structure 50. Haze may occur.

Further, when the potential applied to the first electrode 30 and the second electrode 40 is set to zero and no voltage is applied, the nanoparticles 62 run through the insulating liquid 61, and as shown in FIG. 3A, the nanoparticles 62 Returns to a state in which is uniformly dispersed throughout the insulating liquid 61.

The optical device 1 configured as described above is an active type optical control device capable of changing the optical action by controlling the refractive index matching between the concave-convex structure 50 and the refractive index variable layer 60 by an electric field. That is, the optical device 1 can be switched to a plurality of optical modes by controlling the voltage applied between the first electrode 30 and the second electrode 40. In the present embodiment, the optical device 1 is switched to three modes: a first optical mode (first light distribution mode), a second optical mode (second light distribution mode), and a third optical mode (transparent mode). Can be done.

The electric field generated by the voltage applied between the first electrode 30 and the second electrode 40 is likely to be applied to the one having a lower dielectric constant. Therefore, the dielectric constant of the concave-convex structure 50 (convex portion 51) should be larger than the dielectric constant of the insulating liquid 61 of the variable refractive index layer 60. That is, it is preferable that the dielectric constant of the insulating liquid 61 is lower than that of the concave-convex structure 50 (convex portion 51). As a result, it is possible to prevent the electric field from being trapped in the concave-convex structure 50.

[Summary]
As described above, according to the optical device 1 according to the present embodiment, the concave-convex structure 50 and the variable refractive index layer 60 are arranged between the first electrode 30 and the second electrode 40, and the variable refractive index layer 60 is used. An insulating liquid 61 (nanoparticle dispersion layer) in which charged nanoparticles 62 are dispersed is used.

With this configuration, the nanoparticles 62 run through the insulating liquid 61 by applying a voltage between the first electrode 30 and the second electrode 40, so that the refractive index of the variable refractive index layer 60 can be changed. it can. Specifically, the particle distribution of the nanoparticles 62 in the variable refractive index layer 60 changes, and the refractive index distribution of the variable refractive index layer 60 changes. As a result, the difference in refractive index between the concave-convex structure 50 and the variable refractive index layer 60 changes, so that the traveling direction of the light incident on the optical device 1 can be controlled.

In this embodiment, a high refractive index material is used as the nanoparticles 62. Specifically, the refractive index of the nanoparticles 62 is made higher than the refractive index of the insulating liquid 61. More specifically, the refractive index of the nanoparticles 62 is made higher than the refractive index of the uneven structure 50.

In the optical device 1, when no voltage is applied between the first electrode 30 and the second electrode 40 (when no voltage is applied), the refractive index of the refractive index variable layer 60 is the refraction of the concave-convex structure 50. It is different from the rate. Specifically, when no voltage is applied, the refractive index of the variable refractive index layer 60 is higher than that of the concave-convex structure 50. Therefore, when no voltage is applied, a difference in refractive index occurs between the concave-convex structure 50 and the variable refractive index layer 60, and the optical device 1 enters the first light distribution mode to emit light incident on the first substrate 10. Light is distributed to transmit the second substrate 20.

Further, when the first voltage is applied between the first electrode 30 and the second electrode 40, the nanoparticles 62 having a high refractive index migrate toward the uneven structure 50 and are unevenly distributed on the uneven structure 50 side. As a result, the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 becomes higher than the refractive index of the second region 60b on the second electrode side of the variable refractive index layer 60. Therefore, when the first voltage is applied, a difference in refractive index occurs between the concave-convex structure 50 and the variable refractive index layer 60, and the optical device 1 enters the second light distribution mode, which is the same as the first light distribution mode. , The light incident on the first substrate 10 is distributed and transmitted through the second substrate 20.

At this time, when the first voltage is applied, the nanoparticles 61 are unevenly distributed on the concave-convex structure 50 side of the variable refractive index layer 60, so that the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is a voltage. It will be higher than when no application is applied. As a result, when the first voltage is applied (second light distribution mode), the refractive index between the concave-convex structure 50 and the first region 60a of the refractive index variable layer 60 is higher than when no voltage is applied (first light distribution mode). The difference becomes large. Therefore, when the first voltage is applied (second light distribution mode), the optical device 1 distributes the light incident on the first substrate 10 at a steeper angle than when no voltage is applied (first light distribution mode). Then, the second substrate 20 is transmitted.

Further, when a second voltage different from the first voltage is applied between the first electrode 30 and the second electrode 40, nanoparticles 62 having a high refractive index migrate toward the second electrode 40 and second. It is unevenly distributed on the electrode 40 side. As a result, the refractive index of the first region 60a on the concave-convex structure 50 side of the variable refractive index layer 60 is lower than the refractive index of the second region 60b on the second electrode 40 side of the variable refractive index layer 60, and the concave-convex structure 50 It becomes almost the same as the refractive index of. Therefore, when the second voltage is applied, the difference in the refractive index between the concave-convex structure 50 and the variable refractive index layer 60 disappears, the optical device 1 enters the transparent mode, and the light incident on the first substrate 10 travels straight. The second substrate 20 is allowed to pass through.

The optical device 1 according to the present embodiment configured as described above has a large refractive index difference (Δn) between the concave-convex structure 50 and the variable refractive index layer 60 as compared with the optical device in which the variable refractive index layer is a liquid crystal layer. Therefore, the light distribution control range can be increased.

For example, when the variable refractive index layer is a liquid crystal layer, the variable refractive index layer (liquid crystal layer) has a refractive index of 1.5 because the refractive index changes only within the range of 1.5 to 1.7. The maximum difference in refractive index from the uneven structure is 0.2.

On the other hand, in the optical device 1 of the present embodiment, the variable refractive index layer 60 is composed of nanoparticles 62 having a refractive index of 2.1 and an insulating liquid 61 having a refractive index of about 1.5. The variable refractive index layer 60 can partially change the refractive index in the range of 1.5 to 2.1. As a result, the maximum refractive index difference of the variable refractive index layer 60 from the concave-convex structure 50 having a refractive index of 1.5 is 0.6.

By increasing the difference in refractive index between the concave-convex structure 50 and the variable refractive index layer 60 in this way, the angle at which the light incident on the optical device 1 is reflected by the concave-convex structure 50 can be increased or decreased. The range (light distribution control range) that can be used can be expanded. That is, the range of the light distribution angle can be expanded.

Further, the optical device 1 in the present embodiment can improve the light distribution rate as compared with the optical device in which the variable refractive index layer is a liquid crystal layer. That is, since the liquid crystal layer is composed of liquid crystal molecules having birefringence, an optical device using the liquid crystal layer can distribute only one of S wave and P wave. On the other hand, since the insulating liquid 61 and the nanoparticles 62 are independent of the S wave and the P wave, the optical device 1 in the present embodiment can be used for both the S wave and the P wave. Light can be distributed. Therefore, the optical device 1 in the present embodiment has twice the light distribution rate as that of the optical device using the liquid crystal layer.

As described above, according to the optical device 1 in the present embodiment, the light distribution control range can be increased and the light distribution rate can be improved as compared with the optical device in which the variable refractive index layer is a liquid crystal layer. be able to. Therefore, an optical device having excellent light distribution performance can be realized.

Further, when the optical device 1 is in the first light distribution mode (when the first voltage is applied), it is unevenly distributed on the first electrode 30 side in order to make the entire upper side surface of the convex portion 51 of the concave-convex structure 50 a reflective surface. The nanoparticles 62 may exist so as to fill all the recesses (the region between the two adjacent protrusions 51) of the concave-convex structure 50. That is, the nanoparticles 62 may be present up to the apex of the convex portion 51. In this case, the amount of nanoparticles 62 required to fill all the recesses of the concave-convex structure 50 depends on the height of the concave-convex structure 50 and the thickness of the variable refractive index layer 60, and the nanoparticles 62 in the insulating liquid 61. It may be determined by adjusting the concentration of.

(Modification example)
The optical device according to the present invention has been described above based on the embodiment, but the present invention is not limited to the above embodiment.

For example, in the above embodiment, the nanoparticles 62 are positively charged, but are not limited to this. That is, the nanoparticles 62 may be negatively charged.

Further, in the above embodiment, in the second optical mode, a negative potential is applied to the first electrode 30 and a positive potential is applied to the second electrode 40, but the present invention is not limited to this. For example, if a predetermined voltage (potential difference) is applied between the first electrode 30 and the second electrode 40, a positive potential is applied to both the first electrode 30 and the second electrode 40 in the second optical mode. A negative potential may be applied to both of them.

Similarly, in the third optical mode, a positive potential is applied to the first electrode 30 and a negative potential is applied to the second electrode 40, but the present invention is not limited to this. For example, if a predetermined voltage (potential difference) is applied between the first electrode 30 and the second electrode 40, a positive potential is applied to both the first electrode 30 and the second electrode 40 in the third optical mode. A negative potential may be applied.

Further, in the above embodiment, the convex portion 51 constituting the concave-convex structure 50 is a long triangular prism having a triangular cross-sectional shape, but the present invention is not limited to this. For example, the convex portion 51 may be an elongated substantially quadrangular prism having a substantially trapezoidal cross section. Further, the cross-sectional shape of the side surface of the convex portion 51 is not limited to a straight line, but may be a curved line or a saw shape. Further, each of the plurality of convex portions 51 is not limited to one elongated member extending in the X-axis direction, and may be partially divided in the X-axis direction.

Further, in the above embodiment, the heights of the plurality of convex portions 51 are constant, but the height is not limited to this. For example, the heights of the plurality of convex portions 51 may be randomly different. Alternatively, the spacing between the protrusions 51 may be randomly different, or both the height and the spacing may be random.

Further, in the above embodiment, sunlight is exemplified as the light incident on the optical device 1, but the present invention is not limited to this. For example, the light incident on the optical device 1 may be light emitted by a light emitting device such as a lighting fixture.

Further, in the above embodiment, the optical device 1 is arranged in the window so that the longitudinal direction of the convex portion 51 is the X-axis direction, but the present invention is not limited to this. For example, the optical device 1 may be arranged in the window so that the longitudinal direction of the convex portion 51 is the Z-axis direction.

Further, in the above embodiment, the optical device 1 is attached to the window, but the optical device 1 may be used as the window itself of the building. Further, the optical device 1 is not limited to the case where it is installed in a window of a building, and may be installed in, for example, a window of a car.

In addition, in addition, a form obtained by applying various modifications to the above-described embodiment, or a combination of components and functions in each of the above-described embodiments without departing from the spirit of the present invention. The embodiment realized by the above is also included in the present invention.

1 Optical device 10 1st substrate 20 2nd substrate 30 1st electrode 40 2nd electrode 50 Concavo-convex structure 60 Refractive index variable layer (nanoparticle dispersion layer)
60a 1st region 60b 2nd region

Claims (14)

The first substrate with light transmission and
A light-transmitting second substrate arranged to face the first substrate and
The first electrode arranged on the second substrate side of the first substrate and
Concavo-convex structure arranged on the second substrate side of the first electrode and
The second electrode arranged on the first substrate side of the second substrate and
It is provided with a refractive index variable layer which is arranged between the uneven structure and the second electrode and whose refractive index changes according to a voltage applied between the first electrode and the second electrode.
The variable refractive index layer has an insulating liquid and charged nanoparticles dispersed in the insulating liquid.
The refractive index of the nanoparticles is higher than the refractive index of the insulating liquid.
Optical device. When no voltage is applied between the first electrode and the second electrode, the refractive index of the variable refractive index layer is different from the refractive index of the concave-convex structure.
The optical device according to claim 1. When no voltage is applied between the first electrode and the second electrode, the refractive index of the variable refractive index layer is higher than the refractive index of the concave-convex structure.
The optical device according to claim 2. When a first voltage is applied between the first electrode and the second electrode, the refractive index of the first region on the concave-convex structure side of the variable refractive index layer is the first of the variable refractive index layers. Higher than the refractive index of the second region on the two-electrode side,
The optical device according to any one of claims 1 to 3. When a second voltage different from the first voltage is applied between the first electrode and the second electrode, the refractive index of the first region of the concave-convex structure of the variable refractive index layer is the refraction. It is lower than the refractive index of the second region on the second electrode side of the variable rate layer and is substantially the same as the refractive index of the uneven structure.
The optical device according to claim 4. The optical device according to any one of claims 1 to 5, wherein the refractive index of the nanoparticles is higher than the refractive index of the uneven structure. An optical device that controls incident light
The first substrate with light transmission and
A light-transmitting second substrate arranged to face the first substrate and
The first electrode arranged on the second substrate side of the first substrate and
Concavo-convex structure arranged on the second substrate side of the first electrode and
The second electrode arranged on the first substrate side of the second substrate and
A nanoparticle dispersion layer arranged between the uneven structure and the second electrode and having an insulating liquid and charged nanoparticles dispersed in the insulating liquid is provided.
The optical device controls the traveling direction of light incident on the optical device according to a voltage applied between the first electrode and the second electrode.
Optical device. When no voltage is applied between the first electrode and the second electrode, the optical device distributes the light incident on the first substrate and transmits it through the second substrate.
The optical device according to claim 7. When a first voltage is applied between the first electrode and the second electrode, the optical device transmits light incident on the first substrate between the first electrode and the second electrode. Light is distributed at an angle different from that when no voltage is applied to the second substrate.
The optical device according to claim 8. When a first voltage is applied between the first electrode and the second electrode, the optical device transmits light incident on the first substrate between the first electrode and the second electrode. Light is distributed at a steeper angle than when no voltage is applied to the second substrate.
The optical device according to claim 8. When a second voltage different from the first voltage is applied between the first electrode and the second electrode, the optical device causes the light incident on the first substrate to travel straight through the first electrode. Make the two substrates transparent,
The optical device according to claim 9 or 10. The first substrate with light transmission and
A light-transmitting second substrate arranged to face the first substrate and
The first electrode arranged on the second substrate side of the first substrate and
Concavo-convex structure arranged on the second substrate side of the first electrode and
The second electrode arranged on the first substrate side of the second substrate and
A nanoparticle dispersion layer arranged between the uneven structure and the second electrode and having an insulating liquid and charged nanoparticles dispersed in the insulating liquid is provided.
The particle distribution of the nanoparticles in the nanoparticle dispersion layer changes according to the voltage applied between the first electrode and the second electrode.
Optical device. When the first voltage is applied between the first electrode and the second electrode, the nanoparticles are unevenly distributed in the first region on the uneven structure side in the nanoparticle dispersion layer.
The optical device according to claim 12. When a second voltage different from the first voltage is applied between the first electrode and the second electrode, the nanoparticles are the second electrode side of the second electrode in the nanoparticle dispersion layer. Unevenly distributed in the area,
The optical device according to claim 13.

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