JP2020003577A - Light distribution control device - Google Patents

Abstract

To provide a light distribution device that, when used in windows, can brighten indoors, and can suppress glare persons staying indoors feel.SOLUTION: A light distribution control device 1 comprises: an optical device 2; and a light control film 3. The optical device 2 comprises: a first electrode layer 40; a second electrode layer 50; and a light distribution layer 30 arranged between the first electrode layer 40 and the second electrode layer 50. The light distribution layer 30 includes: a first concavity convexity structure layer 31 that has a plurality of first convexity parts 33; and a refractive index variable layer 32 that is arranged so as to fill between the plurality of first convexity parts 33. The light control film 3 comprises: a second concavity convexity structure layer 60 that has a plurality of second convexity parts 63; a third concavity convexity structure layer 70 that has a plurality of third convexity parts 73; and an air layer 80. An inclination angle αof the first convexity part 33 is equal to or more than 12° and equal to or less than 20°, and an inclination angle αis equal to or more than 8°, and equal to or less than 13°. An inclination angle β of the second convexity part 63 and an inclination angle γ of the third convexity part 73 are equal to or more than 55°, and equal to or less than 80°.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light distribution control device.

  For example, Patent Document 1 discloses a liquid crystal optical element having a configuration in which a liquid crystal layer and an inclined cross-section structure layer are sandwiched between two transparent electrode layers. By adjusting the orientation of the liquid crystal molecules contained in the liquid crystal layer by the voltage applied between the transparent electrode layers, a difference in the refractive index occurs at the interface between the inclined cross-section structure layer and the liquid crystal layer, and the light distribution characteristics of the liquid crystal optical element Is changing.

JP 2015-41006 A

  When the above-mentioned conventional liquid crystal optical element is used for a window, the interior of the room can be brightened by bending the transmitted light and illuminating the ceiling of the room. However, the conventional liquid crystal optical element has a problem that, when used in a window, a person indoors feels dazzling due to a part of the light that cannot be bent toward the ceiling.

  Therefore, an object of the present invention is to provide a light distribution control device that can brighten the interior of a room when used in a window and can suppress glare felt by people indoors. .

  In order to achieve the above object, a light distribution control device according to one embodiment of the present invention is a light distribution control device including an optical device and a light control film, wherein the optical device has a first light-transmitting property. A substrate, a light-transmitting second substrate disposed opposite to the first substrate, and a light-transmitting second substrate disposed between the first substrate and the second substrate. A first electrode layer and a second electrode layer, and a light distribution layer that is disposed between the first electrode layer and the second electrode layer and distributes incident light. A first concave-convex structure layer having a plurality of first convex portions arranged side by side along a first direction; and a first concave-convex structure layer disposed so as to fill a space between the plurality of first convex portions. A refractive index variable layer whose refractive index changes according to a voltage applied between two electrode layers; A film having a second uneven structure layer having a plurality of second protrusions, a third uneven structure layer having a plurality of third protrusions disposed opposite to each of the plurality of second protrusions, An air space positioned between the plurality of second protrusions and the plurality of third protrusions, wherein each of the plurality of first protrusions includes a first surface and a second surface intersecting in the first direction. A surface, and each of the plurality of second protrusions has a third surface and a fourth surface that intersect in the first direction, and each of the plurality of third protrusions is in the first direction. A fifth surface that intersects the sixth surface, an angle formed by the first surface with respect to a surface orthogonal to the first direction is 12 ° or more and 20 ° or less, and a surface orthogonal to the first direction. The angle formed by the second surface is 8 ° or more and 13 ° or less, and the angle formed by each of the third surface and the fifth surface with respect to the first direction is 55 ° or more and 8 ° or more. ° is less than or equal to.

  Further, a light distribution control device according to another aspect of the present invention is an optical device, a light distribution control device including a light control film, the optical device, a first substrate having a light transmittance, A light-transmitting second substrate disposed opposite to the first substrate; and a light-transmitting first substrate disposed between the first substrate and the second substrate. An electrode layer, a second electrode layer, and a light distribution layer disposed between the first electrode layer and the second electrode layer and distributing incident light, wherein the light distribution layer has a first direction. A first concavo-convex structure layer having a plurality of first protrusions arranged side by side with the first electrode layer and the second electrode layer disposed so as to fill a space between the plurality of first protrusions. A refractive index variable layer whose refractive index changes according to a voltage applied to the light control film. A second uneven structure layer having a second convex portion, a third uneven structure layer having a plurality of third convex portions arranged to face each of the plurality of second convex portions, A light distribution control device having a light distribution rate higher than 48%, and a light directivity rate of the light distribution control device being 14%. Lower.

  ADVANTAGE OF THE INVENTION According to the light distribution control device which concerns on this invention, when it is used for a window, indoors can be made bright and glare perceived by the person who is indoors can be suppressed.

FIG. 1 is a cross-sectional view illustrating a light distribution control device according to an embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of a plurality of uneven structure layers included in the light distribution control device according to the embodiment. FIG. 3A is a cross-sectional view illustrating a non-application mode (transparent state) of the optical device of the light distribution control device according to the embodiment. FIG. 3B is a cross-sectional view illustrating a voltage application mode (light distribution state) of the optical device of the light distribution control device according to the embodiment. FIG. 4 is a cross-sectional view illustrating a path of light passing through the light distribution control device according to the embodiment in the voltage application mode. FIG. 5 is a diagram illustrating a relationship between a combination of the inclination angle α _up and the inclination angle α _down of the first convex portion of the optical device according to the embodiment and the light distribution rate. FIG. 6 is a diagram illustrating a relationship between a combination of the inclination angle α _up and the inclination angle α _down of the first convex portion of the optical device according to the embodiment and the direct incidence rate. FIG. 7 is a diagram illustrating a relationship between the inclination angle α _up of the first convex portion and the light distribution rate of the light distribution control device according to the present embodiment. FIG. 8 is a diagram illustrating the relationship between the inclination angle α _down of the first convex portion and the light distribution rate of the light distribution control device according to the present embodiment. FIG. 9 is a diagram showing the relationship between the light distribution rate and the inclination angle β of the second convex portion and the inclination angle γ of the third convex portion of the light distribution control device according to the present embodiment. FIG. 10 is a diagram showing the relationship between the distance D between the tops of the second convex portion and the third convex portion of the light distribution control device according to the present embodiment and the light distribution rate. FIG. 11 is a diagram illustrating a relationship between the inclination angle α _up of the first convex portion and the direct incidence rate of the light distribution control device according to the present embodiment. FIG. 12 is a diagram illustrating a relationship between the inclination angle α _down of the first convex portion and the direct incidence of the light distribution control device according to the present embodiment. FIG. 13 is a diagram illustrating the relationship between the directivity and the inclination angle β of the second convex portion and the inclination angle γ of the third convex portion of the light distribution control device according to the present embodiment. FIG. 14 is a diagram illustrating the relationship between the distance D between the tops of the second convex portion and the third convex portion of the light distribution control device according to the present embodiment, and the direct incidence.

  Hereinafter, a light distribution control device according to an embodiment of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement and connection forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present invention. Therefore, among the components in the following embodiments, components not described in the independent claims are described as arbitrary components.

  In addition, each drawing is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, the scales and the like do not always match in each drawing. Further, in each of the drawings, substantially the same configuration is denoted by the same reference numeral, and redundant description will be omitted or simplified.

  Also, in this specification, a term indicating a relationship between elements such as parallel or vertical, and a term indicating a shape of an element such as a rectangle or a trapezoid, and a numerical range are not expressions expressing only a strict meaning, This is an expression that means that it includes a substantially equivalent range, for example, a difference of about several percent.

  In this specification and the drawings, the x-axis, the y-axis, and the z-axis indicate three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the z-axis direction is the vertical direction, and the direction perpendicular to the z-axis (the direction parallel to the xy plane) is the horizontal direction. Note that the positive direction of the z-axis is vertically upward. In this specification, the “thickness direction” means the thickness direction of the light distribution control device, and is a direction perpendicular to the main surfaces of the first substrate and the second substrate. That is, the thickness direction corresponds to the normal direction of the first substrate, and corresponds to the y-axis direction. The “plan view” refers to when viewed from a direction perpendicular to the main surface of the first substrate or the second substrate.

(Embodiment)
[Overview]
First, an outline of a light distribution control device according to an embodiment will be described with reference to FIG.

  FIG. 1 is a sectional view showing a light distribution control device 1 according to the present embodiment.

  The light distribution control device 1 controls light incident on the light distribution control device 1. Specifically, the light distribution control device 1 is a light distribution element that can change the traveling direction of light incident on the light distribution control device 1, that is, can distribute and emit light.

  As shown in FIG. 1, the light distribution control device 1 includes an optical device 2 and a light control film 3. Each of the optical device 2 and the light control film 3 is configured to transmit incident light.

  The optical device 2 includes a first substrate 10, a second substrate 20, a light distribution layer 30, a first electrode layer 40, and a second electrode layer 50, as shown in FIG. The optical device 2 has a configuration in which a first electrode layer 40, a light distribution layer 30, and a second electrode layer 50 are arranged in this order along a thickness direction between a pair of a first substrate 10 and a second substrate 20. It is. In order to keep the distance between the first substrate 10 and the second substrate 20, a plurality of particulate spacers may be dispersed in the plane, or a columnar structure may be formed.

  Further, an adhesion layer for adhering the first electrode layer 40 and the first uneven structure layer 31 of the light distribution layer 30 may be provided on the surface of the first electrode layer 40 on the light distribution layer 30 side. . The adhesion layer is, for example, a translucent adhesive sheet or a resin material generally called a primer.

  As shown in FIG. 1, the light control film 3 includes a second uneven structure layer 60, a third uneven structure layer 70, an air layer 80, and a base layer 90. By arranging the second uneven structure layer 60 and the third uneven structure layer 70 at a predetermined interval, an air layer 80 is provided between the second uneven structure layer 60 and the third uneven structure layer 70. ing. Although not shown, an annular sealing member is provided along the outer periphery of each of the second uneven structure layer 60 and the third uneven structure layer 70. By keeping the distance between the second uneven structure layer 60 and the third uneven structure layer 70 constant by the sealing member, the shape of the air layer 80 is maintained.

  As shown in FIG. 1, the second substrate 20 of the optical device 2 and the second concavo-convex structure layer 60 of the light control film 3 are directly bonded, but the present invention is not limited to this. For example, the light control film 3 may include a base layer that supports the second uneven structure layer 60. The base layer may be attached to the second substrate 20. An adhesive layer may be provided between the optical device 2 and the light control film 3.

  The light distribution control device 1 can be realized as a window with a light distribution function, for example, by being installed in a window of a building. The light distribution control device 1 is used by being attached to a transparent base material such as an existing window glass via an adhesive layer, for example. Alternatively, the light distribution control device 1 may be used as a window of a building itself. The light distribution control device 1 is arranged so that, for example, the optical device 2 is on the outdoor side and the light control film 3 is on the indoor side. Specifically, in the light distribution control device 1, the first surface 36 (see FIG. 2) of the first convex portion 33 of the first uneven structure layer 31 faces upward (toward the ceiling), and the second surface 37 (see FIG. 2). 2 (see FIG. 2) face downward (floor side).

  In the light distribution control device 1, the refractive index of the refractive index variable layer 32 of the light distribution layer 30 changes according to the voltage applied between the first electrode layer 40 and the second electrode layer 50 of the optical device 2. As a result, a difference in refractive index occurs at the interface between the first uneven structure layer 31 and the refractive index variable layer 32, and light is distributed using refraction and reflection (total reflection) of light at the interface. For example, at least a part of the light that enters obliquely downward is reflected by the first protrusion 33, and is emitted obliquely upward.

  The optical device 2 switches between a transparent state and a light distribution state according to the magnitude of the voltage applied between the first electrode layer 40 and the second electrode layer 50. In the optical device 2, the light distribution direction (emission direction) of light in the light distribution state changes according to the magnitude of the voltage applied between the first electrode layer 40 and the second electrode layer 50.

  Hereinafter, each component of the light distribution control device 1 will be described in detail with reference to FIG.

[First substrate, second substrate and base material layer]
The first substrate 10, the second substrate 20, and the base layer 90 are base materials having a light transmitting property. As the first substrate 10, the second substrate 20, and the base layer 90, for example, a glass substrate or a resin substrate can be used.

  Examples of the material for the glass substrate include soda glass, non-alkali glass, and high refractive index glass. Examples of the material of the resin substrate include resin materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), acrylic (PMMA), and epoxy. The glass substrate has the advantages of high light transmittance and low moisture permeability. On the other hand, the resin substrate has an advantage that scattering at the time of destruction is small.

  The first substrate 10, the second substrate 20, and the base layer 90 may be made of the same material or may be made of different materials. Further, the first substrate 10, the second substrate 20, and the base material layer 90 are not limited to the rigid substrates, but may be flexible substrates having flexibility. In the present embodiment, the first substrate 10, the second substrate 20, and the base layer 90 are transparent resin substrates made of PET resin.

  The second substrate 20 is a facing substrate facing the first substrate 10, and is disposed at a position facing the first substrate 10. The first substrate 10 and the second substrate 20 are arranged in parallel at a predetermined distance such as 1 μm to 1000 μm. The first substrate 10 and the second substrate 20 are adhered to each other by a sealing resin such as an adhesive formed in a frame shape on the outer periphery of the end.

  In addition, the planar shape of the first substrate 10, the second substrate 20, and the base material layer 90 is, for example, a rectangular shape such as a square or a rectangle, but is not limited thereto, and may be a polygon other than a circle or a square. And any shape may be employed.

[Light distribution layer]
As shown in FIG. 1, the light distribution layer 30 is disposed between the first electrode layer 40 and the second electrode layer 50. The light distribution layer 30 has a light-transmitting property and transmits incident light. The light distribution layer 30 distributes incident light. That is, when the light passes through the light distribution layer 30, the light distribution layer 30 changes the traveling direction of the light.

  The light distribution layer 30 includes a first uneven structure layer 31 and a variable refractive index layer 32. In the present embodiment, the light traveling at the interface between the first uneven structure layer 31 and the refractive index variable layer 32 is bent in the vertical direction of the light passing through the light distribution control device 1.

[First uneven structure layer]
The first uneven structure layer 31 is a fine-shaped layer provided to make the surface (interface) of the refractive index variable layer 32 uneven. The first uneven structure layer 31 is provided on the first electrode layer 40. As shown in FIG. 1, the first uneven structure layer 31 includes a plurality of first protrusions 33, a plurality of first recesses 34, and a base layer 35.

  Specifically, the first concavo-convex structure layer 31 is a concavo-convex structure formed by a plurality of first convex portions 33 having a micro-order size. A plurality of first concave portions 34 are between the plurality of first convex portions 33. That is, a portion between two adjacent first convex portions 33 is one first concave portion 34. In the example shown in FIG. 1, an example is shown in which the plurality of first convex portions 33 are individually separated and supported by the base layer 35 at the base, but the present invention is not limited to this. The plurality of first protrusions 33 may be connected to each other at the root (on the first electrode layer 40 side). Further, a flat surface may not be provided at the bottom of the first concave portion 34.

  The plurality of first protrusions 33 are a plurality of protrusions arranged on the main surface of the first substrate 10 along the z-axis direction (first direction) via the first electrode layer 40. That is, in the present embodiment, the z-axis direction is the direction in which the plurality of first protrusions 33 are arranged.

  In the present embodiment, the plurality of first protrusions 33 are long protrusions extending in a direction orthogonal to the arrangement direction. Specifically, the plurality of first protrusions 33 are formed in a stripe shape extending in the x-axis direction (second direction). Each of the plurality of first protrusions 33 extends linearly along the x-axis direction. For example, each of the plurality of first protrusions 33 is a quadrangular prism arranged sideways with respect to the first electrode layer 40. Note that the plurality of first convex portions 33 may extend while meandering along the x-axis direction. For example, the plurality of first protrusions 33 may be formed in a wavy stripe shape in plan view.

  As shown in FIG. 1, each of the plurality of first protrusions 33 has a shape that tapers from the root to the tip. Specifically, the cross-sectional shape of each of the plurality of first protrusions 33 is a tapered shape that tapers in a direction from the first substrate 10 toward the second substrate 20 (that is, the positive direction of the y-axis). In the present embodiment, the cross-sectional shape of the first convex portion 33 in the yz cross section is a trapezoid that tapers along the thickness direction of the light distribution control device 1, but is not limited thereto. The cross-sectional shape of the first convex portion 33 may be a triangle, another polygon, a polygon including a curve, or the like. In the present embodiment, the plurality of first protrusions 33 have the same height (length in the y-axis direction). The height of the plurality of first protrusions 33 is, for example, 2 μm to 100 μm, but is not limited thereto.

  Alternatively, the plurality of first protrusions 33 may include a plurality of first protrusions having different heights. For example, two adjacent first protrusions 33 may have different heights in the direction in which the plurality of first protrusions 33 are arranged. The height of each of the plurality of first protrusions 33 is, for example, a value randomly selected from a plurality of set values.

  Note that a trapezoid or a triangle includes a trapezoid or a triangle having a rounded vertex. In addition, the trapezoid or triangle may include a case where each side is not completely straight, for example, a case where each side is slightly bent with a displacement of about several% of the length of each side, or a case where minute irregularities are included. included.

  FIG. 2 is a cross-sectional view for explaining a configuration of a plurality of uneven structure layers included in the light distribution control device 1 according to the present embodiment. In FIG. 2, hatching representing a cross section is not attached for easy understanding.

FIG. 2 also shows the light L incident on the light distribution control device 1 and its incident angle θ _in, and the light L emitted from the light distribution control device 1 and its exit angle θ _out . The outgoing angle θ _out of the light L is light (light distribution) in which light in the range of 3.6 ° or more and 80 ° or less is distributed. Also, the light L is light (direct light) from which light having an emission angle θ _{out in} a range of −43 ° or more and 3.6 ° or less is directly incident. The details of light distribution and direct light will be described later.

  In the present embodiment, as shown in FIG. 2, each of the plurality of first protrusions 33 has a first surface 36 and a second surface 37. The first surface 36 and the second surface 37 are surfaces that intersect in the z-axis direction. Each of the first surface 36 and the second surface 37 is an inclined surface inclined at a predetermined inclination angle with respect to the y-axis direction. The distance between the first surface 36 and the second surface 37, that is, the width of the first protrusion 33 gradually decreases from the first substrate 10 toward the second substrate 20.

  The first surface 36 is, for example, a vertically upper side surface among a plurality of side surfaces constituting the first convex portion 33 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. . The first surface 36 is a reflection surface that reflects incident light. Here, the reflection is total reflection, and the first surface 36 functions as a total reflection surface.

As shown in FIG. 2, the inclination angle α _up of the first surface 36 is an angle formed by the first surface 36 with respect to a surface 36a orthogonal to the z-axis direction. The surface 36a is, for example, a virtual surface passing through the positive end of the first surface 36 in the y-axis direction, and is a surface parallel to the xy plane. The inclination angle α _up of the first surface 36 is 12 ° or more and 20 ° or less. The inclination angles α _up of the first surfaces 36 of the plurality of first protrusions 33 may be equal to each other or may be different.

  The second surface 37 is, for example, a vertically lower side surface among a plurality of side surfaces constituting the first convex portion 33 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. . The second surface 37 is a refraction surface that refracts incident light.

The inclination angle α _down of the second surface 37 is an angle formed by the second surface 37 with respect to a surface 37a orthogonal to the z-axis direction. The surface 37a is, for example, a virtual surface passing through the positive end of the second surface 37 in the y-axis direction, and is a surface parallel to the xy plane. The inclination angle α _down of the second surface 37 is not less than 8 ° and not more than 13 °. The inclination angle α _down of the second surface 37 of each of the plurality of first protrusions 33 may be equal to or different from each other.

  The width (the length in the z-axis direction) of the plurality of first protrusions 33 is, for example, 1 μm to 20 μm, and preferably 10 μm or less, but is not limited thereto. In addition, the interval between two adjacent first protrusions 33 is, for example, 0 μm to 100 μm, but is not limited thereto.

  The base layer 35 is provided between the first electrode layer 40 and the plurality of first protrusions 33 and is a layer that supports the plurality of first protrusions 33. The base layer 35 is formed integrally with the plurality of first protrusions 33 using the same material as the plurality of first protrusions 33. As a material of the plurality of first protrusions 33 and the base layer 35, for example, a resin material having optical transparency such as an acrylic resin, an epoxy resin, or a silicone resin can be used.

  The plurality of first protrusions 33 and the base layer 35 are formed of, for example, an ultraviolet curable resin material, and can be formed by molding or nanoimprinting. The plurality of first convex portions 33 can be formed by, for example, using an acrylic resin having a refractive index of 1.5 for green light and molding and embossing a concave-convex structure having a trapezoidal cross section. The portion remaining as a residual film during the molding of the plurality of first convex portions 33 corresponds to the base layer 35. The thickness of the base layer 35 is, for example, uniform.

[Refractive index variable layer]
The refractive index variable layer 32 is provided so as to fill a space between the plurality of first convex portions 33 (that is, the first concave portions 34). Specifically, the refractive index variable layer 32 is disposed so as to fill a gap formed between the first electrode layer 40 and the second electrode layer 50. As shown in FIG. 1, when the tip of the first protrusion 33 is separated from the second electrode layer 50, the refractive index variable layer 32 includes not only the first recess 34 but also the first protrusion. It is arranged so as to fill the gap between the tip of 33 and the second electrode layer 50.

  The refractive index of the refractive index variable layer 32 changes according to the voltage applied between the first electrode layer 40 and the second electrode layer 50. Specifically, the refractive index variable layer 32 functions as a refractive index adjustment layer that can adjust the refractive index in the visible light band by applying a voltage between the electrode layers. For example, a DC voltage is applied between the first electrode layer 40 and the second electrode layer 50 by a control unit (not shown).

  As shown in FIG. 1, the refractive index variable layer 32 has an insulating liquid 38 and nanoparticles 39 included in the insulating liquid 38. The refractive index variable layer 32 is a nanoparticle dispersion layer in which countless nanoparticles 39 are dispersed in an insulating liquid 38. The insulating liquid 38 is filled between the first uneven structure layer 31 and the second electrode layer 50.

  The insulating liquid 38 is a transparent liquid having an insulating property, and is a solvent serving as a dispersion medium in which the nanoparticles 39 are dispersed as a dispersoid. As the insulating liquid 38, for example, a material having a refractive index (solvent refractive index) of about 1.3 to about 1.6 can be used. In the present embodiment, the insulating liquid 38 having a refractive index of about 1.4 is used.

Note that the kinematic viscosity of the insulating liquid 38 is preferably about 100 mm ² / s. Further, the insulating liquid 38 has a low dielectric constant (for example, lower than the dielectric constant of the first uneven structure layer 31), a non-flammable (for example, a high flash point whose flash point is 250 ° C. or higher) and a low volatility. May be. Specifically, the insulating liquid 38 is a hydrocarbon such as an aliphatic hydrocarbon, naphtha, and other petroleum-based solvents, a low-molecular-weight halogen-containing polymer, or a mixture thereof. As an example, the insulating liquid 38 is a halogenated hydrocarbon such as a fluorinated hydrocarbon. Note that, as the insulating liquid 38, silicone oil or the like can be used.

  A plurality of the nanoparticles 39 are dispersed in the insulating liquid 38. The nanoparticles 39 are fine particles having a nano-order size. Specifically, assuming that the wavelength of the incident light is λ, the particle size of the nanoparticles 39 is preferably λ / 4 or less. By setting the particle diameter of the nanoparticles 39 to λ / 4 or less, light scattering by the nanoparticles 39 can be reduced, and an average refractive index between the nanoparticles 39 and the insulating liquid 38 can be obtained. The particle size of the nanoparticles 39 is preferably as small as possible, preferably 100 nm or less, and more preferably several nm to several tens nm.

  The nanoparticles 39 are made of, for example, a high refractive index material. Specifically, the refractive index of the nanoparticles 39 is higher than the refractive index of the insulating liquid 38. In the present embodiment, the refractive index of the nanoparticles 39 is higher than the refractive index of the first uneven structure layer 31.

As the nanoparticles 39, for example, metal oxide fine particles can be used. Further, the nanoparticles 39 may be made of a material having a high transmittance. In the present embodiment, as the nanoparticles 39, transparent zirconia particles having a refractive index of 2.1 and made of zirconium oxide (ZrO ₂ ) are used. The nanoparticles 39 are not limited to zirconium oxide, but may be made of titanium oxide (TiO ₂ : refractive index 2.5).

  The nanoparticles 39 are charged charged particles. For example, by modifying the surface of the nanoparticles 39, the nanoparticles 39 can be charged positively (plus) or negatively (minus). In the present embodiment, the nanoparticles 39 are positively (plus) charged.

  In the variable refractive index layer 32 configured as described above, the charged nanoparticles 39 are dispersed throughout the insulating liquid 38. In the present embodiment, as an example, zirconia particles having a refractive index of 2.1 are used as the nanoparticles 39 and dispersed in an insulating liquid 38 having a solvent refractive index of about 1.4. And

  The refractive index (average refractive index) of the entire refractive index variable layer 32 is substantially the same as the refractive index of the first uneven structure layer 31 in a state where the nanoparticles 39 are uniformly dispersed in the insulating liquid 38. It is set and is about 1.5 in the present embodiment. The overall refractive index of the refractive index variable layer 32 can be changed by adjusting the concentration (amount) of the nanoparticles 39 dispersed in the insulating liquid 38. The amount of the nanoparticles 39 is, for example, such that the nanoparticles 39 are buried in the first concave portions 34 of the first uneven structure layer 31. In this case, the concentration of the nanoparticles 39 with respect to the insulating liquid 38 is about 10% to about 30%.

  Since the nanoparticles 39 dispersed in the insulating liquid 38 are charged, when a voltage is applied between the first electrode layer 40 and the second electrode layer 50, the nanoparticles 39 have the polarity of the nanoparticles 39. Migrates in the insulating liquid 38 so as to be attracted to the electrode layer having a different polarity from that of the insulating liquid 38, and is unevenly distributed in the insulating liquid 38. In the present embodiment, since the nanoparticles 39 are positively charged, the nanoparticles 39 are attracted to the negative electrode layer of the first electrode layer 40 and the second electrode layer 50.

  Thereby, the particle distribution of the nanoparticles 39 in the variable refractive index layer 32 changes, and the concentration distribution of the nanoparticles 39 can be provided in the variable refractive index layer 32. The distribution changes. That is, the refractive index of the refractive index variable layer 32 partially changes. As described above, the refractive index variable layer 32 mainly functions as a refractive index adjusting layer that can adjust the refractive index for light in the visible light band.

  The refractive index variable layer 32 is formed, for example, at each end of the first substrate 10 on which the first electrode layer 40 and the first uneven structure layer 31 are formed and the second substrate 20 on which the second electrode layer 50 is formed. It is formed by injecting a variable refractive index material by a vacuum injection method in a state where the outer periphery is sealed with a seal resin. Alternatively, the variable refractive index layer 32 is formed by dropping a variable refractive index material on the first electrode layer 40 and the first uneven structure layer 31 of the first substrate 10 and then forming the second substrate 20 on which the second electrode layer 50 is formed. May be formed by bonding together. In the present embodiment, the variable refractive index material is an insulating liquid 38 in which nanoparticles 39 are dispersed. An insulating liquid 38 in which nanoparticles 39 are dispersed is sealed between the first substrate 10 and the second substrate 20. The thickness of the refractive index variable layer 32 is, for example, 1 μm to 1000 μm, but is not limited thereto.

[First electrode layer and second electrode layer]
As shown in FIG. 1, the first electrode layer 40 and the second electrode layer 50 are electrically paired. The first electrode layer 40 and the second electrode layer 50 are paired not only electrically but also in arrangement, and are arranged between the first substrate 10 and the second substrate 20 so as to face each other. ing. Specifically, the first electrode layer 40 and the second electrode layer 50 are arranged so as to sandwich the light distribution layer 30.

  The first electrode layer 40 and the second electrode layer 50 have a light-transmitting property and transmit incident light. The first electrode layer 40 and the second electrode layer 50 are, for example, transparent conductive layers. Examples of the material of the transparent conductive layer include a conductive metal-containing resin such as a transparent metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), a resin containing a conductive material such as silver nanowires or conductive particles, or And a metal thin film such as a silver thin film. Note that the first electrode layer 40 and the second electrode layer 50 may have a single-layer structure thereof, or may have a laminated structure thereof (for example, a laminated structure of a transparent metal oxide and a metal thin film). In the present embodiment, each of the first electrode layer 40 and the second electrode layer 50 is ITO having a thickness of 100 nm.

  The first electrode layer 40 is arranged between the first substrate 10 and the first uneven structure layer 31. Specifically, the first electrode layer 40 is formed on the surface of the first substrate 10 on the light distribution layer 30 side.

  On the other hand, the second electrode layer 50 is disposed between the variable refractive index layer 32 and the second substrate 20. Specifically, the second electrode layer 50 is formed on the surface of the second substrate 20 on the light distribution layer 30 side.

  The first electrode layer 40 and the second electrode layer 50 are configured such that, for example, electrical connection with an external power supply is possible. Specifically, each end of the first electrode layer 40 and the second electrode layer 50 is drawn out of the sealing member and formed on each of the first substrate 10 and the second substrate 20. .

  The first electrode layer 40 and the second electrode layer 50 are each formed by depositing a conductive film such as ITO by, for example, vapor deposition, sputtering, or the like.

[Second uneven structure layer]
As shown in FIG. 1, the second uneven structure layer 60 has a plurality of second protrusions 63 and a plurality of second recesses 64. Specifically, the second concavo-convex structure layer 60 is a concavo-convex structure formed by a plurality of second convex portions 63 having a micro-order size. A plurality of second concave portions 64 are between the plurality of second convex portions 63. That is, a portion between two adjacent second convex portions 63 is one second concave portion 64. Although the example shown in FIG. 1 shows an example in which the plurality of second protrusions 63 are connected at the base and formed in a saw-tooth shape, the present invention is not limited to this. The plurality of second convex portions 63 may be individually separated at the root (on the side of the first electrode layer 40), or a flat surface may be provided at the bottom of the second concave portion 64.

  The plurality of second protrusions 63 are formed on the main surface (the surface opposite to the surface on which the first electrode layer 40 is provided) of the second substrate 20 along the z-axis direction. Department. In the present embodiment, the arrangement direction of the plurality of second protrusions 63 is the same as the arrangement direction of the plurality of first protrusions 33.

  In the present embodiment, the plurality of second protrusions 63 are long protrusions extending in a direction orthogonal to the arrangement direction. Specifically, the plurality of second protrusions 63 are formed in a stripe shape extending in the x-axis direction (second direction). The plurality of second convex portions 63 extend linearly along the x-axis direction. For example, each of the plurality of second convex portions 63 is a triangular prism arranged sideways. Note that the plurality of second convex portions 63 may extend while meandering along the x-axis direction. For example, the plurality of second convex portions 63 may be formed in a wavy stripe shape in plan view.

  As shown in FIG. 1, each of the plurality of second convex portions 63 has a shape that tapers from the root to the tip. Specifically, the cross-sectional shape of each of the plurality of second convex portions 63 is a tapered shape that tapers along the direction from the second substrate 20 toward the base material layer 90 (that is, the positive direction of the y-axis). In the present embodiment, the cross-sectional shape of the second convex portion 63 in the yz cross-section is a triangle that tapers along the thickness direction of the light distribution control device 1, but is not limited thereto. The cross-sectional shape of the second convex portion 63 may be a trapezoid, another polygon, a polygon including a curve, or the like.

In the present embodiment, each of the plurality of second convex portions 63 has the same shape and size. For example, the plurality of second protrusions 63 have the same height (length in the y-axis direction). The height _Hb of the plurality of second convex portions 63 is, for example, several hundreds μm or less, and is 200 μm as an example, but is not limited thereto. The plurality of second protrusions 63 may include protrusions having different heights.

  As shown in FIG. 2, each of the plurality of second protrusions 63 has a third surface 66 and a fourth surface 67. The third surface 66 and the fourth surface 67 are surfaces that intersect in the z-axis direction. At least one of the third surface 66 and the fourth surface 67 is an inclined surface inclined at a predetermined inclination angle with respect to the y-axis direction. The distance between the third surface 66 and the fourth surface 67, that is, the width of the second convex portion 63 gradually decreases in the positive y-axis direction.

  The third surface 66 is, for example, a vertically upper side surface among a plurality of side surfaces constituting the second convex portion 63 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. . The third surface 66 corresponds to an interface with the air layer 80, and totally reflects a part of light incident from the optical device 2 side. The third surface 66 functions as a total reflection surface.

  The inclination angle β of the third surface 66 is an angle formed by the third surface 66 with respect to the z-axis direction. As shown in FIG. 2, the inclination angle β is an angle formed between a surface 66a parallel to the z-axis direction and the third surface 66. The surface 66a is, for example, a virtual surface passing through the negative end of the third surface 66 in the y-axis direction, and is a surface parallel to the xz plane. The inclination angle β of the third surface 66 is 55 ° or more and 80 ° or less. The inclination angles β of the third surfaces 66 of the plurality of second convex portions 63 may be equal to each other or may be different.

  The fourth surface 67 is, for example, a vertically lower side surface among a plurality of side surfaces forming the second convex portion 63 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. . The fourth surface 67 corresponds to an interface with the air layer 80, and can totally reflect the light incident from the optical device 2 side depending on the incident angle with respect to the fourth surface 67. The fourth surface 67 can function not only as a surface through which the downward irradiation light passes but also as a total reflection surface.

  The fourth surface 67 is orthogonal to the z-axis direction. That is, the cross-sectional shape of the second convex portion 63 is a right triangle. Note that the fourth surface 67 may be inclined with respect to the z-axis direction.

  The second uneven structure layer 60 is formed using, for example, a transparent resin material such as an acrylic resin, an epoxy resin, or a silicone resin. For example, the second concavo-convex structure layer 60 is formed from an ultraviolet curable resin material, and can be formed by molding or nanoimprinting. The second uneven structure layer 60 can be formed by, for example, using an acrylic resin having a refractive index of 1.5 for green light and mold-pressing an uneven structure having a triangular cross section.

[Third uneven structure layer]
As shown in FIG. 1, the third uneven structure layer 70 has a plurality of third protrusions 73 and a plurality of third recesses 74. Specifically, the third concavo-convex structure layer 70 is a concavo-convex structure formed by a plurality of third convex portions 73 having a micro-order size. A plurality of third concave portions 74 are located between the plurality of third convex portions 73. That is, one third concave portion 74 is located between two adjacent third convex portions 73. In the example shown in FIG. 1, an example is shown in which the plurality of third convex portions 73 are connected at the root and formed in a sawtooth shape, but the present invention is not limited to this. The plurality of third convex portions 73 may be individually separated at the root (the base material layer 90 side), or a flat surface may be provided at the bottom of the third concave portion 74. In the present embodiment, the third uneven structure layer 70 has a shape in which the second uneven structure layer 60 is turned upside down and left and right.

  The plurality of third protrusions 73 are a plurality of protrusions arranged on the main surface of the base material layer 90 along the z-axis direction. In the present embodiment, the direction in which the plurality of third protrusions 73 are arranged is the same as the direction in which the plurality of first protrusions 33 are arranged.

  In the present embodiment, the plurality of third protrusions 73 are long protrusions extending in a direction orthogonal to the arrangement direction. Specifically, the plurality of third convex portions 73 are formed in a stripe shape extending in the x-axis direction (second direction). The plurality of third convex portions 73 extend linearly along the x-axis direction. For example, each of the plurality of third convex portions 73 is a triangular prism arranged sideways. Note that the plurality of third convex portions 73 may extend while meandering along the x-axis direction. For example, the plurality of third convex portions 73 may be formed in a wavy stripe shape in plan view.

  As shown in FIG. 1, each of the plurality of third convex portions 73 has a shape that tapers from the root to the tip. Specifically, the cross-sectional shape of each of the plurality of third convex portions 73 is a tapered shape that tapers along the direction from the base material layer 90 toward the second substrate 20 (that is, the negative direction of the y-axis). In the present embodiment, the cross-sectional shape of the third convex portion 73 in the yz cross section is a triangular shape tapering along the thickness direction of the light distribution control device 1, but is not limited thereto. The cross-sectional shape of the third convex portion 73 may be a trapezoid, another polygon, a polygon including a curve, or the like.

In the present embodiment, each of the plurality of third convex portions 73 has the same shape and size. For example, the plurality of third convex portions 73 have the same height (length in the y-axis direction). The height H _c of the plurality of third protrusions 73, for example, several hundreds μm or less, is a 200μm way of example and not limited thereto. The plurality of third convex portions 73 may include convex portions having different heights.

  As shown in FIG. 2, each of the plurality of third protrusions 73 has a fifth surface 76 and a sixth surface 77. The fifth surface 76 and the sixth surface 77 are surfaces that intersect in the z-axis direction. At least one of the fifth surface 76 and the sixth surface 77 is an inclined surface inclined at a predetermined inclination angle with respect to the y-axis direction. The distance between the fifth surface 76 and the sixth surface 77, that is, the width of the third convex portion 73 gradually decreases in the negative y-axis direction.

  The fifth surface 76 is, for example, a vertically lower side surface among a plurality of side surfaces constituting the third convex portion 73 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. . The fifth surface 76 corresponds to an interface with the air layer 80.

  The inclination angle γ of the fifth surface 76 is an angle formed by the fifth surface 76 with respect to the z-axis direction. As shown in FIG. 2, the inclination angle γ is an angle formed between a surface 76a parallel to the z-axis direction and the fifth surface 76. The surface 76a is, for example, a virtual surface passing through the positive end in the y-axis direction of the fifth surface 76, and is a surface parallel to the xz plane. The inclination angle γ of the fifth surface 76 is 55 ° or more and 80 ° or less. The inclination angles γ of the fifth surfaces 76 of the plurality of third convex portions 73 may be equal to each other or may be different.

  The sixth surface 77 is, for example, a vertically lower side surface among a plurality of side surfaces constituting the third convex portion 73 when the light distribution control device 1 is arranged so that the z-axis coincides with the vertical direction. .

  The sixth surface 77 is orthogonal to the z-axis direction. That is, the cross-sectional shape of the third convex portion 73 is a right triangle. Note that the sixth surface 77 may be obliquely inclined with respect to the z-axis direction.

  The third uneven structure layer 70 is formed using a transparent resin material such as an acrylic resin, an epoxy resin, or a silicone resin. For example, the third concavo-convex structure layer 70 is formed of an ultraviolet curable resin material, and can be formed by molding or nanoimprinting. The third concavo-convex structure layer 70 can be formed by, for example, using an acrylic resin having a refractive index of 1.5 for green light and mold-pressing a concavo-convex structure having a triangular cross section.

[Position relationship between air layer and second and third convex portions]
In the light control film 3 according to the present embodiment, the plurality of second protrusions 63 and the plurality of third protrusions 73 are arranged so as not to be in contact with each other but to be opposed to each other. Is formed. The air layer 80 is an air layer located between the plurality of second protrusions 63 and the plurality of third protrusions 73. The air layer 80 has a refractive index substantially equal to one.

  As shown in FIG. 1, the plurality of second protrusions 63 and the plurality of third protrusions 73 are alternately arranged one by one along the z-axis direction. That is, the top 63 a of each of the plurality of second protrusions 63 is located between two adjacent third protrusions 73, that is, inside the third recess 74. Similarly, each top 73 a of the plurality of third protrusions 73 is located between two adjacent second protrusions 63, that is, inside the second recess 64. As described above, the second convex portion 63 and the third concave portion 74 correspond one-to-one, and the third convex portion 73 and the second concave portion 64 correspond one-to-one.

  Note that the top 63 a of the second convex portion 63 corresponds to a distal end in the projecting direction of the second convex portion 63. Specifically, the top 63a of the second convex portion 63 is a tip in the positive direction of the y-axis. In the present embodiment, the top 63a of the second projection 63 corresponds to the intersection of the third surface 66 and the fourth surface 67.

  Similarly, the top portion 73a of the third convex portion 73 corresponds to a tip portion of the third convex portion 73 in the protruding direction. Specifically, the top part 73a of the third convex part 73 is a tip part in the negative direction of the y-axis. In the present embodiment, the top portion 73a of the third convex portion 73 corresponds to an intersection between the fifth surface 76 and the sixth surface 77.

  Since the top 63a of the second protrusion 63 is located in the third recess 74 and the top 73a of the third protrusion 73 is located in the second recess 64, as shown in FIGS. The air layer 80 is provided such that its cross-sectional shape becomes zigzag. Specifically, the air layer 80 is formed between the third surface 66 of the second protrusion 63 and the fifth surface 76 of the third protrusion 73, and between the fourth surface 67 of the second protrusion 63 and the third surface 67. This corresponds to a space sandwiched between the projection 73 and the sixth surface 77. In the present embodiment, the third surface 66 and the fifth surface 76 are parallel, and the fourth surface 67 and the sixth surface 77 are parallel. Thereby, the air layer 80 is provided in a zigzag shape with a uniform thickness.

At this time, the distance in the y-axis direction between the top 63a of the second projection 63 and the top 73a of the third projection 73 is represented by the pushing distance D shown in FIG. In this embodiment, the pushing distance D is less than 85% to 100% of the height _{H b} and a height _{H c} of the third convex portion 73 of the second projection 63. In this embodiment, the height H _b of the second convex portion 63 is equal to the height H _c of the third convex portion 73, may be different.

[Operation and optical state of optical device]
Subsequently, an operation and an optical state of the optical device 2 of the light distribution control device 1 according to the present embodiment will be described.

<Transparent state (no application mode)>
FIG. 3A is an enlarged cross-sectional view illustrating a non-application mode (transparent state) of optical device 2 of light distribution control device 1 according to the present embodiment. In FIG. 3A, the paths of the light L1 to L3 obliquely incident on the light distribution control device 1 (optical device 2) are indicated by arrows. The lights L1 to L3 are incident lights parallel to each other like sunlight.

  In FIG. 3A, no voltage is applied between the first electrode layer 40 and the second electrode layer 50. Specifically, the first electrode layer 40 and the second electrode layer 50 have the same potential. In this case, since the nanoparticles 39 are not attracted to any electrode layer, the nanoparticles 39 are dispersed throughout the insulating liquid 38.

  In the present embodiment, the refractive index of the refractive index variable layer 32 in a state where the nanoparticles 39 are dispersed throughout the insulating liquid 38 is about 1.5 as described above. Further, the refractive index of the first convex portion 33 of the first uneven structure layer 31 is about 1.5. That is, the plurality of first convex portions 33 and the refractive index variable layer 32 have the same refractive index. Therefore, the refractive index becomes uniform over the entire light distribution layer 30.

For this reason, as shown in FIG. 3A, when light L1 to L3 is incident obliquely downward from obliquely upward, there is no difference in the refractive index at the interface between the variable refractive index layer 32 and the first uneven structure layer 31. So the light travels straight. That is, in the yz section, the incident angle θ _in and the output angle θ _out of the light L1 to L3 are substantially the same.

  As described above, the optical device 2 of the light distribution control device 1 is in a transparent state in which the incident light is transmitted substantially as it is (without changing the traveling direction).

  Note that the light L1 to L3 actually enter the first substrate 10, exit from the second substrate 20, pass through the interface between the first substrate 10 and the first electrode layer 40, and The light is refracted when passing through the interface between the second electrode layer 50 and the second substrate 20 or when the passing medium changes, but is not shown in FIG. 3A. The same applies to FIG. 3B described later.

<Light distribution state (voltage application mode)>
FIG. 3B is an enlarged cross-sectional view for explaining a voltage application mode (light distribution state) of the optical device 2 of the light distribution control device 1 according to the present embodiment. In FIG. 3B, the paths of the light L1 to L3 obliquely incident on the light distribution control device 1 are indicated by thick arrows. The lights L1 to L3 are incident lights parallel to each other like sunlight. Here, each of the lights L1 to L3 is light that passes through the second surface 37 of the first convex portion 33.

  In FIG. 3B, a predetermined voltage is applied between the first electrode layer 40 and the second electrode layer 50. For example, a voltage having a potential difference of about several tens of volts is applied to the first electrode layer 40 and the second electrode layer 50. Thereby, in the refractive index variable layer 32, the charged nanoparticles 39 migrate in the insulating liquid 38 so as to be attracted to the electrode layer having a polarity different from the polarity of the nanoparticles 39. That is, the nanoparticles 39 electrophores within the insulating liquid 38.

  In the example shown in FIG. 3B, the second electrode layer 50 has a higher potential than the first electrode layer 40. Therefore, the positively charged nanoparticles 39 migrate toward the first electrode layer 40 on the low potential side, enter the first concave portions 34 of the first uneven structure layer 31, and accumulate.

  As described above, since the nanoparticles 39 are unevenly distributed on the first uneven structure layer 31 side in the variable refractive index layer 32, the particle distribution of the nanoparticles 39 changes, and the refractive index distribution in the variable refractive index layer 32 becomes one. It is not like. Specifically, as shown in FIG. 3B, a concentration distribution of the nanoparticles 39 is formed in the refractive index variable layer 32.

  For example, in the region on the first electrode layer 40 side, the concentration of the nanoparticles 39 is high, and in the region on the second electrode layer 50 side, the concentration of the nanoparticles 39 is low. Therefore, there is a difference in refractive index between the region on the first electrode layer 40 side and the region on the second electrode layer 50 side.

  In the present embodiment, the refractive index of the nanoparticles 39 is higher than the refractive index of the insulating liquid 38. For this reason, the refractive index of the region where the concentration of the nanoparticles 39 is high is higher than the refractive index of the region where the concentration of the nanoparticles 39 is low, that is, the ratio of the insulating liquid 38 is high. For example, the refractive index in the region on the first electrode layer 40 side is a value larger than about 1.5 to about 1.8 depending on the concentration of the nanoparticles 39. The refractive index in the region on the second electrode layer 50 side becomes a value of about 1.4 to less than about 1.5 depending on the concentration of the nanoparticles 39.

Since the refractive index of the plurality of first protrusions 33 is about 1.5, when a voltage is applied between the first electrode layer 40 and the second electrode layer 50, the first protrusions 33 and the first There is a difference in the refractive index between the region in the concave portion 34 and the region in the concave portion 34. For this reason, as shown in FIG. 3B, when the lights L1 to L3 enter from oblique directions, the incident lights L1 to L3 are refracted by the second surface 37 of the first convex portion 33. The light L3 refracted by the second surface 37 is totally reflected by the first surface 36 and is emitted from the second substrate 20 at an emission angle θ3 _out . As shown in FIG. 3B, the light L3 is emitted from the second substrate 20 obliquely upward by the total reflection by the first surface 36. That is, the light L3 is emitted as distributed light.

Note that the lights L1 and L2 refracted by the second surface 37 do not enter the first surface 36, and thus are emitted from the second substrate 20 as they are. Emission angle .theta.1 _out and .theta.2 _out at this time is different from the incident angle theta _in respect to the first substrate 10 of the light L1 and L2.

  As described above, when a predetermined voltage is applied between the first electrode layer 40 and the second electrode layer 50, the refractive index is formed at the interface between each of the plurality of first protrusions 33 and the refractive index variable layer 32. A difference occurs, and the traveling direction of at least a part of the light incident on the light distribution layer 30 is bent. That is, the optical device 2 of the light distribution control device 1 enters a light distribution state in which at least a part of the incident light is transmitted while bending the traveling direction thereof.

  In addition, the degree of aggregation of the nanoparticles 39 can be changed according to the magnitude of the applied voltage. The refractive index of the refractive index variable layer 32 changes according to the degree of aggregation of the nanoparticles 39. Therefore, the light distribution direction can be changed by changing the difference in the refractive index between the first surface 36 and the second surface 37 (interface) of the first convex portion 33.

[Characteristics of light control film]
In the present embodiment, the light control film 3 is provided on the light emission side of the optical device 2 performing the above-described operation, that is, on the main surface of the second substrate 20. By providing the light control film 3, the light distribution rate and the direct light rate are improved. Hereinafter, the principle will be schematically described with reference to FIG.

  FIG. 4 is a cross-sectional view illustrating a path of light passing through the light distribution control device 1 according to the present embodiment in the voltage application mode. In FIG. 4, the paths of the light L1 to L3 obliquely incident on the light distribution control device 1 are indicated by arrows. The lights L1 to L3 are incident lights parallel to each other like sunlight. Here, all of the lights L1 to L3 are lights that pass through the second surface 37 of the first convex portion 33, and are lights that enter the same angles and the same positions as the lights L1 to L3 illustrated in FIG. 3B.

  As shown in FIG. 4, the light L <b> 1 is refracted on the second surface 37 of the first protrusion 33 and then enters the third surface 66 of the second protrusion 63 of the second uneven structure layer 60. Since the third surface 66 is an interface with the air layer 80, the light L1 incident on the third surface 66 is totally reflected by the third surface 66. The light L1 totally reflected by the third surface 66 is refracted by the fourth surface 67, passes through the air layer 80, and is refracted again by the sixth surface 77 of the third uneven structure layer 70. The light L1 refracted by the sixth surface 77 is emitted from the base material layer 90.

At this time, the emission angle θ1 _out of the light L1 is larger than the emission angle θ1 _{out of the} light L1 shown in FIG. 3B. In other words, the light L <b> 1 is emitted as light traveling downward from a case where the light control film 3 is not provided. The light control film 3 is emitted as downward irradiation light which is out of the range (-43 ° to 3.6 °) of the direct light shown in FIG.

  As described above, since the light control film 3 is provided, the light L1 emitted as the direct light when the light control film 3 is not provided is the downward irradiation light, that is, the light L1 is not the direct light. It is emitted as light. Thereby, the light distribution control device 1 according to the present embodiment can reduce direct light by including the light control film 3.

  Further, as shown in FIG. 4, the light L <b> 2 is refracted by the second surface 37 of the first convex portion 33, and then enters the fourth surface 67 of the second convex portion 63 of the second uneven structure layer 60. At this time, the light L2 is incident on the fourth surface 67 at a smaller angle (larger incident angle) than the light L1 totally reflected by the third surface 66. Therefore, the light L2 is totally reflected by the fourth surface 67. The light L2 totally reflected by the fourth surface 67 is refracted by the third surface 66, passes through the air layer 80, and is refracted again by the fifth surface 76 of the third uneven structure layer 70. The light L2 refracted by the fifth surface 76 is emitted from the base material layer 90.

At this time, unlike the light L2 shown in FIG. 3B, the light L2 is emitted obliquely upward. Specifically, the emission angle θ2 _out of the light L2 is included in the light distribution range (3.6 ° to 80 °) illustrated in FIG. That is, the light L2 is emitted as distributed light.

  As described above, since the light control film 3 is provided, the light L2 emitted as direct light when the light control film 3 is not provided is emitted as distributed light. Accordingly, the light distribution control device 1 according to the present embodiment can reduce the direct light and increase the distributed light by including the light control film 3.

  Note that the light L3 shown in FIG. 4 is light distributed even when the light control film 3 is not provided, as in FIG. 3B. The light L3 is refracted by the third surface 66 of the second convex portion 63 of the second uneven structure layer 60, passes through the air layer 80, and passes through the fifth surface of the third convex portion 73 of the third uneven structure layer 70. After being refracted at 76, the light is emitted from the base material layer 90.

  In the present embodiment, since the third surface 66 and the fifth surface 76 are parallel, the light L3 before being refracted by the third surface 66 and the light L3 after being refracted by the fifth surface 76 are different. Be parallel. That is, even if the light control film 3 is provided, the light L3 which is the light distributed when the light control film 3 is not provided has substantially the same emission angle. Therefore, assuming that the light control film 3 is provided, a change in the light distribution characteristics of the light distribution control device 1 is suppressed, and the light to be distributed can be increased.

  As described above, the light distribution control device 1 according to the present embodiment includes the light control film 3 so that the light distribution rate is higher than that of the optical device 2 and the direct light rate is lower. it can.

[Relationship between shape of light control film and light distribution rate and direct light rate]
Hereinafter, as described above, the details of the shape of the light control film 3 that can increase the light distribution rate and reduce the direct light rate will be described.

  First, as a comparative example, the case where the light distribution control device 1 does not include the light control film 3, that is, the dependence of the light distribution rate and direct light rate of only the optical device 2 on the shape of the first convex portion 33 is shown in FIG. This will be described with reference to FIG.

FIG. 5 is a diagram showing a relationship between a combination of the inclination angles α _up and α _down of the first convex portion 33 of the optical device 2 according to the present embodiment and the light distribution rate. FIG. 6 is a diagram showing a relationship between a combination of the inclination angles α _up and α _down of the first convex portion 33 of the optical device 2 according to the present embodiment and the direct incidence. 5 and 6, the horizontal axis represents the inclination angle α _up , and the vertical axis represents the light distribution rate or direct light rate.

In the present embodiment, the light distribution ratio indicates the ratio of the light distribution intensity to the intensity of all incident light. The light distribution is, as shown in FIG. 2, light having an emission angle θ _{out in} a range of 3.6 ° or more and 80 ° or less among the lights emitted from the light distribution control device 1. The range of the light distribution emission angle θ _out is determined on the assumption that the light distribution control device 1 is provided within a range of a height from the floor surface of 1.5 m or more and 2.7 m or less. Note that the same applies to the range of the direct irradiation rate described later.

Specifically, 3.6 ° which is the lower limit of the light distribution range is a person who stands at a point 1.6 m away from the light distribution control device 1 and has a line-of-sight height of 1.6 m. The value corresponds to the boundary between when light distributed at the lower end of the light distribution control device 1 (that is, at a position at a height of 1.5 m from the floor surface) and when light is not incident. . Specifically, the lower limit is determined by tan ^-1 {(1.6-1.5) /1.6}.

The direct light ratio indicates the ratio of the intensity of direct light to the intensity of all incident light. The direct light is, as shown in FIG. 2, light emitted from the light distribution control device 1 and having an emission angle θ _{out in} a range from −43 ° to 3.6 °. Here, that the emission angle is a negative number means that the light emission direction is below the horizontal plane.

The lower limit of -43 ° of the range of the direct light is a light distribution to the eyes of a person sitting at a point 1.6 m away from the light distribution control device 1 and having a line-of-sight height of 1.2 m. This is a value corresponding to the boundary between when light that is not distributed at the upper end of the control device 1 (that is, at a height of 2.7 m from the floor surface) and is directly incident is not incident. Specifically, the lower limit is determined by tan ^-1 {(2.7-1.2) /1.6}.

As shown in FIG. 5, when the inclination angles α _down are 8 °, 12 °, 16 °, and 20 °, the light distribution ratio becomes maximum when the inclination angle α _up is 16 °. When the inclination angle α _down is 24 °, the light distribution ratio becomes maximum when the inclination angle α _up is 12 °. In particular, when the inclination angle α _up is 16 ° and the inclination angle α _down is 8 ° or 12 °, the light distribution rate is maximized at about 53%.

On the other hand, as shown in FIG. 6, when the inclination angles α _down are 8 °, 12 °, 16 °, and 20 °, the _directivity is minimized when the inclination angle α _up is 12 °. In addition, when the inclination angle α _down is 24 °, the direct incidence becomes minimum when the inclination angle α _up is 8 °. In particular, when the inclination angle α _up is 12 ° and the inclination angle α _down is 12 °, the direct incidence is minimum at 14%. On the other hand, when the inclination angle α _up is 16 ° and the inclination angle α _down is 8 ° or 12 °, which is the combination that maximizes the light distribution rate, the direct sunlight rate becomes 23% or 17%. I have.

From the viewpoint of suppressing unnecessarily glare, when the inclination angle α _up is 12 ° and the inclination angle α _down is 12 °, the light distribution rate is 48% and the direct light rate is 14%. Thus, an optimum combination of the inclination angles is obtained. In the present embodiment, by laminating the light control film 3 on the optical device 2, the light distribution rate is increased and the direct light rate is reduced. Specifically, the light distribution control device 1 has a light distribution rate higher than 48% and a direct light rate lower than 14%. For example, the light distribution rate of the light distribution control device 1 is 54%, and the direct light rate is 7%. Note that the light distribution rate of the light distribution control device 1 may be higher than 54%, and the direct light rate may be lower than 7%.

For this reason, the inclination angles α _up and α _down of the first projections 33 of the first uneven structure layer 31 of the optical device 2 and the inclination angles of the second projections 63 of the second uneven structure layer 60 of the light control film 3. Appropriate ranges of β, the inclination angle γ of the third convex portion 73 of the third concave-convex structure layer 70, and the distance D between the tops of the second convex portion 63 and the third convex portion 73 were determined based on the following simulation results. . Specifically, α _up , α _down , β, γ, and D are determined so that the direct light rate is reduced within a range in which the light distribution rate of the light distribution control device 1 does not become 48% or less.

  First, conditions for increasing the light distribution ratio will be described with reference to FIGS.

FIG. 7 is a diagram illustrating a relationship between the light distribution rate and the inclination angle α _up of the first convex portion 33 of the light distribution control device 1 according to the present embodiment. FIG. 7 shows the light distribution rates of the light distribution control device 1 when the inclination angles α _up are 8 °, 12 °, 16 °, 20 °, and 24 °. In addition, the dashed line indicates 48%, which is the optimum light distribution rate of the optical device 2 alone without the light control film 3, as shown in FIG. The same applies to the broken lines in FIGS. The light distribution ratio shown in FIG. 7 is an average value when parameters other than the inclination angle α _up (specifically, the inclination angles α _down , β and γ, and the pushing distance D) are changed.

As shown in FIG. 7, the light distribution ratio is higher than 48% when the inclination angle α _up is in the range from 12 ° to 20 °. That is, when the inclination angle α _up is in the range of 12 ° or more and 20 ° or less, it is understood that the light distribution ratio is improved by providing the light control film 3.

FIG. 8 is a diagram showing the relationship between the inclination angle α _down of the first convex portion 33 of the light distribution control device 1 according to the present embodiment and the light distribution rate. FIG. 8 shows the light distribution rates of the light distribution control device 1 when the inclination angles α _down are 8, 12, 16, 20, and 24 degrees. The light distribution rate shown in FIG. 8 is an average value when parameters other than the inclination angle α _down (specifically, the inclination angles α _up , β and γ, and the pushing distance D) are changed.

As shown in FIG. 8, the light distribution rate is higher than 48% in a range where the inclination angle α _down is 13 ° or less. That is, when the inclination angle α _down is in the range of 13 ° or less, it can be seen that the light distribution rate is improved by providing the light control film 3.

FIG. 9 is a diagram illustrating a relationship between the light distribution rate and the inclination angle β of the second convex portion 63 and the inclination angle γ of the third convex portion 73 of the light distribution control device 1 according to the present embodiment. The inclination angle β and the inclination angle γ have the same value. FIG. 9 shows the light distribution ratio of the light distribution control device 1 when the inclination angles β and γ are 10 °, 20 °, 30 °, 40 °, 50 °, 60 °, 70 °, and 80 °. The light distribution rate shown in FIG. 9 is an average value when parameters other than the inclination angles β and γ (specifically, the inclination angles α _up and α _down and the pushing distance D) are changed.

  As shown in FIG. 9, the light distribution ratio is higher than 48% when the inclination angles β and γ are in the range of 45 ° to 80 °. That is, when the inclination angles β and γ are in the range of 45 ° or more and 80 ° or less, it is understood that the light distribution ratio is improved by providing the light control film 3.

FIG. 10 is a diagram showing the distance between the tops of the second convex portion 63 and the third convex portion 73 of the light distribution control device 1 according to the present embodiment, that is, the relationship between the pushing distance D and the light distribution rate. is there. FIG. 10 shows the light distribution ratio of the light distribution control device 1 when the pushing distance D is 110 μm, 130 μm, 150 μm, 170 μm, and 190 μm. The light distribution ratio shown in FIG. 10 is an average value when parameters other than the pushing distance D (specifically, the inclination angles α _up , α _down , β and γ) are changed. In this case, the height _{H b} and a height _{H c} of the third convex portion 73 of the second convex portion 63 is 200 [mu] m.

As shown in FIG. 10, the light distribution ratio is higher than 48% when the indentation distance D is 170 μm or more. That is, in the range ratio is more than 85% of the pushing distance D to the height _{H b} and _{H c,} Haihikariritsu is higher than 48%. That is, the ratio of the pushing distance D to the height H _b and H _c is by providing the light control film 3 to be 85% or more, it can be seen that Haihikariritsu is improved.

As described above, the conditions for increasing the light distribution ratio to more than 48% are as follows: the inclination angle α _up of the first convex portion 33 is 12 ° or more and 20 ° or less, and the inclination angle α _down is 8 ° or more and 13 ° or less. And the inclination angle β of the second projection 63 and the inclination angle γ of the third projection 73 are 45 ° to 80 °, and the height _Hb of the second projection 63 and the height of the third projection 73 are proportion of pushing distance D is less than 100% to 85% for the _{H c.} Hereinafter, a condition for reducing the direct-radiation rate in a state where the condition is satisfied will be described with reference to FIGS. 11 to 14.

FIG. 11 is a diagram illustrating a relationship between the inclination angle α _up of the first convex portion 33 of the light distribution control device 1 according to the present embodiment and the direct-light rate. FIG. 11 shows the light distribution rates of the light distribution control device 1 when the inclination angles α _up are 8, 12, 16, 20, and 24 degrees. Further, the broken line indicates 14% which is the optimum direct light rate of the optical device 2 alone without the light control film 3 as shown in FIG. The broken line is the same in FIGS. 11 to 14. Further, the direct irradiance shown in FIG. 11 is an average value when parameters other than the inclination angle α _up (specifically, the inclination angles α _down , β and γ, and the pushing distance D) are changed.

As shown in FIG. 11, regardless of the value of the inclination angle α _up , the direct incidence did not fall below 14%. Specifically, when the inclination angle α _up is 8 °, 12 °, 16 °, and 20 °, the direct irradiance is included in the range of 16% to 17% and is almost constant. When the inclination angle α _up was 24 °, the direct incidence was 20%.

As described above, even if the inclination angle α _up is changed, the direct radiation rate does not become lower than 14%, but if the inclination angle α _up is in the range of 12 ° or more and 20 ° or less, the direct radiation rate becomes 16%. １７17%. Therefore, the range of the light distribution ratio can be used as it is as the range of the inclination angle α _up , which is 12 ° or more and 20 ° or less.

FIG. 12 is a diagram illustrating a relationship between the inclination angle α _down of the first convex portion 33 of the light distribution control device 1 according to the present embodiment and the direct incidence. FIG. 12 shows the direct irradiance of the light distribution control device 1 when the inclination angles α _down are 8, 12, 16, 20, and 24 °. Further, the direct irradiance shown in FIG. 12 is an average value when parameters other than the inclination angle α _down (specifically, the inclination angles α _up , β and γ, and the pushing distance D) are changed.

As shown in FIG. 12, in the range where the inclination angle α _down is 23 ° or more, the direct incidence is lower than 14%. On the other hand, when the inclination angles α _down are 8 °, 12 °, 16 °, and 20 °, the direct irradiance is included in the range of 17% to 20% and is almost constant.

As described above, when the inclination angle α _down is 23 ° or more, the direct incidence can be made lower than 14%. However, as shown in FIG. 8, when the inclination angle α _down is 23 ° or more, the light distribution ratio becomes lower than 48%. For this reason, as the range of the inclination angle α _down, the range of the light distribution ratio can be used as it is, and is 8 ° or more and 13 ° or less.

FIG. 13 is a diagram illustrating a relationship between the directivity and the inclination angle β of the second convex portion 63 and the inclination angle γ of the third convex portion 73 of the light distribution control device 1 according to the present embodiment. The inclination angle β and the inclination angle γ have the same value. FIG. 13 shows the direct irradiance of the light distribution control device 1 when the inclination angles β and γ are 10 °, 20 °, 30 °, 40 °, 50 °, 60 °, 70 °, and 80 °. The direct incidence shown in FIG. 13 is an average value when parameters other than the inclination angles β and γ (specifically, the inclination angles α _up and α _down and the pushing distance D) are changed.

  As shown in FIG. 13, when the inclination angles β and γ are in the range of 55 ° to 80 °, the direct irradiance is lower than 14%. As shown in FIG. 9, this range is included in the range of 45 ° or more and 80 ° or less in which the light distribution rate is higher than 48%. That is, when the inclination angles β and γ are in the range of 55 ° or more and 80 ° or less, by providing the light control film 3, the light distribution rate can be increased and the direct light rate can be reduced.

FIG. 14 is a diagram showing the distance between the tops of the second convex portion 63 and the third convex portion 73 of the light distribution control device 1 according to the present embodiment, that is, the relationship between the indentation distance D and the direct radiation rate. . FIG. 14 shows the direct irradiance of the light distribution control device 1 when the pushing distance D is 110 μm, 130 μm, 150 μm, 170 μm, and 190 μm. The direct irradiance shown in FIG. 14 is an average value when parameters other than the pushing distance D (specifically, the inclination angles α _up , α _down , β and γ) are changed. In this case, the height _{H b} and a height _{H c} of the third convex portion 73 of the second convex portion 63 is 200 [mu] m.

As shown in FIG. 14, the direct injection rate did not become lower than 14% regardless of the value of the pushing distance D. Therefore, the range of the ratio of the pushing distance D to the height H _b and H _c is in the range of Haihikariritsu can use it, in the range of less than 85% to 100%.

From the above, the conditions for making the light distribution rate higher than 48% and making the direct light rate lower than 14% are as follows: the inclination angle α _up of the first convex portion 33 is 12 ° or more and 20 ° or less, The inclination angle α _down is 8 ° or more and 13 ° or less, the inclination angle β of the second projection 63 and the inclination angle γ of the third projection 73 are 55 ° or more and 80 ° or less, and the height of the second projection 63 is proportion of pushing distance D is less than 100% to 85% for the _{H b} and a height _{H c} of the third convex portion 73.

[Effects, etc.]
As described above, the light distribution control device 1 according to the present embodiment is a light distribution control device including the optical device 2 and the light control film 3. The optical device 2 includes a first substrate 10 having a light transmitting property, a second substrate 20 having a light transmitting property, which is disposed to face the first substrate 10, and a first substrate 10 and a second substrate 20 having a light transmitting property. A first electrode layer 40 and a second electrode layer 50 having a light-transmitting property, which are disposed to face each other between the first electrode layer 40 and the second electrode layer 50; And a light distribution layer 30 that distributes light. The light distribution layer 30 is disposed so as to fill a space between the plurality of first protrusions 33 and the first uneven structure layer 31 having the plurality of first protrusions 33 arranged side by side along the first direction, And a refractive index variable layer 32 whose refractive index changes according to a voltage applied between the first electrode layer 40 and the second electrode layer 50. The light control film 3 includes a second uneven structure layer 60 having a plurality of second protrusions 63 and a third having a plurality of third protrusions 73 arranged to face each of the plurality of second protrusions 63. An uneven structure layer 70 and an air layer 80 located between the plurality of second protrusions 63 and the plurality of third protrusions 73 are provided. Each of the plurality of first protrusions 33 has a first surface 36 and a second surface 37 that intersect in the first direction. Each of the plurality of second convex portions 63 has a third surface 66 and a fourth surface 67 that intersect in the first direction. Each of the plurality of third convex portions 73 has a fifth surface 76 and a sixth surface 77 that intersect in the first direction. An angle α _up formed by the first surface 36 with respect to a surface orthogonal to the first direction is 12 ° or more and 20 ° or less. An angle α _down formed by the second surface 37 with respect to a surface orthogonal to the first direction is 8 ° or more and 13 ° or less. The angles β and γ formed by the third surface 66 and the fifth surface 76 with respect to the first direction are 55 ° or more and 80 ° or less.

  Thereby, total reflection of light can be caused at the interface between the second uneven structure layer 60 of the light control film 3 and the air layer 80. For example, when the light control film 3 is not provided, a part of the light that has escaped as direct light can be emitted as a light distribution toward the ceiling by total reflection. Alternatively, when the light control film 3 is not provided, another part of the light that has escaped as direct light as it is can be emitted downward by a total reflection to a height lower than the height that can be seen by human eyes. .

  As described above, according to the light distribution control device 1 according to the present embodiment, the light distribution rate can be higher and the direct light rate can be lower than in the case where only the optical device 2 is used. Therefore, when the light distribution control device 1 is used for a window, a large amount of light can be taken indoors, so that the interior can be brightened. In addition, when the light distribution control device 1 is used for a window, it is possible to reduce light that can directly enter a human eye, so that glare perceived by a person indoors can be suppressed.

  In addition, for example, the plurality of second protrusions 63 and the plurality of third protrusions 73 are alternately arranged one by one along the first direction. Each top 63a of the plurality of second protrusions 63 is located between two adjacent third protrusions 73.

  Thereby, the air layer 80 can be thinned, and the light distribution rate can be further increased.

Further, for example, the distance D along the normal direction of the first substrate 10 between the top 63a of the adjacent second protrusion 63 and the top 73a of the third protrusion 73 is equal to the distance between the adjacent second protrusion 63 and Each of the third protrusions 73 is not less than 85% and less than 100% of the length along the normal direction of the first substrate (that is, the heights _Hb and _Hc ).

  Thereby, the air layer 80 can be further thinned, and the light distribution rate can be further increased.

  In addition, for example, in the adjacent second convex portion 63 and third convex portion 73, the third surface 66 and the fifth surface 76 are parallel, and the fourth surface 67 and the sixth surface 77 are parallel. .

  Accordingly, the light distributed when the light control film 3 is not provided has substantially the same emission angle even when the light control film 3 is provided. Therefore, assuming that the light control film 3 is provided, a change in the light distribution characteristics of the light distribution control device 1 is suppressed, and the light to be distributed can be increased.

  Further, for example, the fourth surface 67 and the sixth surface 77 are orthogonal to the first direction.

  Accordingly, when the second uneven structure layer 60 is viewed in a plan view, the proportion occupied by the third surface 66 functioning as the total reflection surface can be maximized. Therefore, of the light transmitted through the optical device 2, more light can be emitted below the direct light by being totally reflected by the third surface 66. Therefore, the direct incidence of the light distribution control device 1 can be further reduced.

  In addition, for example, each of the plurality of first protrusions 33, the plurality of second protrusions 63, and the plurality of third protrusions 73 is an elongated protrusion extending along a second direction orthogonal to the first direction. Department.

  Thereby, since the areas of the light reflection surface and the refraction surface can be secured large, the light distribution rate can be increased and the direct light rate can be reduced.

  Further, for example, the refractive index variable layer 32 includes an insulating liquid 38 and a plurality of charged nanoparticles 39 having a different refractive index from the insulating liquid 38 and dispersed in the insulating liquid 38.

  Thereby, the direction of the light distributed in the light distribution state changes according to the degree of aggregation of the charged nanoparticles 39 dispersed in the insulating liquid 38. The degree of aggregation of the nanoparticles 39 can be easily changed according to the voltage applied between the first electrode layer 40 and the second electrode layer 50. Therefore, the transparent state and the light distribution state can be easily changed. In addition, in the light distribution state, both the P-polarized light and the S-polarized light can influence the difference in the refractive index, so that the light distribution and the transparency can be improved.

In the present embodiment, the inclination angle α _up of the first protrusion 33 does not have to be 12 ° or more and 20 ° or less. The tilt angle α _up may be smaller than 12 ° or larger than 20 °. Similarly, the inclination angle α _down may not be 8 ° or more and 13 ° or less. The inclination angle α _down may be smaller than 8 ° or larger than 13 °. In addition, at least one of the inclination angle β of the second projection 63 and the inclination angle γ of the third projection 73 does not have to be 55 ° or more and 80 ° or less. At least one of the inclination angles β and γ may be smaller than 55 ° or larger than 80 °. The ratio of the pushing distance D to the height _{H b} and a height _{H c} of the third convex portion 73 of the second convex portion 63 may be less than 100% 85% or more. Proportion of pushing distance D to the height _{H b} and _{H c} may be less than 85%. In the light distribution control device 1, the values of α _up , α _down , β, γ, and D are not particularly limited as long as the light distribution rate is higher than 48% and the direct light rate is lower than 14%.

  Further, for example, the light distribution control device 1 according to the present embodiment is a light distribution control device including an optical device 2 and a light control film 3. The optical device 2 includes a first substrate 10 having a light transmitting property, a second substrate 20 having a light transmitting property, which is disposed to face the first substrate 10, and a first substrate 10 and a second substrate 20 having a light transmitting property. A first electrode layer 40 and a second electrode layer 50 having a light-transmitting property, which are disposed to face each other between the first electrode layer 40 and the second electrode layer 50; And a light distribution layer 30 that distributes light. The light distribution layer 30 is disposed so as to fill a space between the plurality of first protrusions 33 and the first uneven structure layer 31 having the plurality of first protrusions 33 arranged side by side along the first direction, And a refractive index variable layer 32 whose refractive index changes according to a voltage applied between the first electrode layer 40 and the second electrode layer 50. The light control film 3 includes a second uneven structure layer 60 having a plurality of second protrusions 63 and a third having a plurality of third protrusions 73 arranged to face each of the plurality of second protrusions 63. An uneven structure layer 70 and an air layer 80 located between the plurality of second protrusions 63 and the plurality of third protrusions 73 are provided. The light distribution rate of the light distribution control device 1 is higher than 48%. The direct light rate of the light distribution control device 1 is lower than 14%.

  Thereby, the light distribution rate can be higher and the direct light rate can be lower than in the case where only the optical device 2 is used. Therefore, when the light distribution control device 1 is used for a window, a large amount of light can be taken indoors, so that the interior can be brightened. In addition, when the light distribution control device 1 is used for a window, it is possible to reduce light that can directly enter a human eye, so that glare perceived by a person indoors can be suppressed.

(Other)
As described above, the light distribution control device according to the present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments.

  For example, in the above-described embodiment, an example has been described in which the top 63a of the second protrusion 63 is located in the third recess 74 and the top 73a of the third protrusion 73 is located in the second recess 64. However, it is not limited to this. For example, the top 63 a of the second protrusion 63 may be located outside the third recess 74, and the top 73 a of the third protrusion 73 may be located outside the second recess 64. That is, the second convex portion 63 and the third convex portion 73 may be separated, and for example, the pushing distance D may be a negative value.

  Further, for example, the first uneven structure layer 31 may be provided on the second substrate 20 side. That is, the first uneven structure layer 31 may be provided on the second electrode layer 50. In this case, the base layer 35 is provided between the second electrode layer 50 and the plurality of first protrusions 33.

  Further, for example, the plurality of first protrusions 33 may be divided into a plurality in the x-axis direction. For example, the plurality of first convex portions 33 may be arranged so as to be scattered in a matrix or the like. That is, the plurality of first protrusions 33 may be arranged so as to be dotted in a dot shape.

  Further, for example, in the above embodiment, the refractive index of the nanoparticles 39 may be lower than the refractive index of the insulating liquid 38. The transparent state and the light distribution state can be realized by appropriately adjusting the applied voltage according to the refractive index of the nanoparticles 39 and the like. For example, the light distribution state may be realized when the voltage is not applied between the first electrode layer 40 and the second electrode layer 50 and the nanoparticles 39 are dispersed in the insulating liquid 38. The transparent state may be realized when a voltage is applied and the nanoparticles 39 are localized on one electrode layer side.

  Further, for example, in the above embodiment, the nanoparticles 39 are positively charged, but the present invention is not limited to this. That is, the nanoparticles 39 may be negatively charged. In this case, a DC voltage is applied between the first electrode layer 40 and the second electrode layer 50 by applying a positive potential to the first electrode layer 40 and applying a negative potential to the second electrode layer 50. May be.

  Further, the plurality of nanoparticles 39 may include a plurality of types of nanoparticles having different optical characteristics. For example, it may include positively charged transparent first nanoparticles and negatively charged opaque (eg, black) second nanoparticles. For example, the light distribution control device 1 may have a light blocking function by aggregating and unevenly distributing the second nanoparticles.

  Further, for example, in the above-described embodiment, an example is described in which an electrophoretic material is used as the variable refractive index material. For example, a liquid crystal material may be used as the variable refractive index material. In this case, the refractive index of the variable refractive index layer changes using the birefringence of liquid crystal molecules contained in the liquid crystal material. By changing the orientation of the liquid crystal molecules according to the electric field applied to the variable refractive index layer, the refractive index of the variable refractive index layer changes. This makes it possible to control the transparent state, the light distribution state, and the light distribution direction in the light distribution state.

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

  Further, for example, the light distribution control device 1 is not limited to being installed in a window of a building, but may be installed in a window of a car, for example. Further, the light distribution control device 1 can be used for a light distribution control member such as a light-transmitting cover of a lighting fixture, for example. Alternatively, the light distribution control device 1 can also be used as a blindfold member using light scattering at the interface of the uneven structure.

  In addition, a form obtained by applying various modifications that can be conceived by those skilled in the art to each embodiment, and a combination of components and functions in each embodiment arbitrarily without departing from the spirit of the present invention are realized. Embodiments are also included in the present invention.

REFERENCE SIGNS LIST 1 light distribution control device 2 optical device 3 light control film 10 first substrate 20 second substrate 30 light distribution layer 31 first uneven structure layer 32 refractive index variable layer 33 first convex portion 36 first surface 37 second surface 38 insulation Ionic liquid 39 nanoparticles 40 first electrode layer 50 second electrode layer 60 second uneven structure layer 63 second protrusions 63a, 73a top 66 third surface 67 fourth surface 70 third uneven structure layer 73 third protrusion 76 Fifth surface 77 Sixth surface 80 Air layer

Claims (8)

An optical device, a light distribution control device including a light control film,
The optical device includes:
A first substrate having optical transparency;
A second substrate having a light-transmitting property, disposed opposite to the first substrate;
A light-transmitting first electrode layer and a second electrode layer disposed opposite to each other between the first substrate and the second substrate;
A light distribution layer disposed between the first electrode layer and the second electrode layer to distribute incident light;
The light distribution layer,
A first uneven structure layer having a plurality of first protrusions arranged side by side along the first direction;
A refractive index variable layer disposed so as to fill between the plurality of first convex portions, and a refractive index of which changes according to a voltage applied between the first electrode layer and the second electrode layer;
The light control film,
A second uneven structure layer having a plurality of second protrusions,
A third concavo-convex structure layer having a plurality of third protrusions disposed opposite to each of the plurality of second protrusions;
An air space located between the plurality of second protrusions and the plurality of third protrusions,
Each of the plurality of first protrusions has a first surface and a second surface that intersect in the first direction,
Each of the plurality of second protrusions has a third surface and a fourth surface that intersect with the first direction,
Each of the plurality of third protrusions has a fifth surface and a sixth surface that intersect with the first direction,
An angle formed by the first surface with respect to a surface orthogonal to the first direction is 12 ° or more and 20 ° or less,
An angle formed by the second surface with respect to a surface orthogonal to the first direction is 8 ° or more and 13 ° or less,
The light distribution control device, wherein an angle formed by each of the third surface and the fifth surface with respect to the first direction is 55 ° or more and 80 ° or less. The plurality of second protrusions and the plurality of third protrusions are alternately arranged one by one along the first direction,
The light distribution control device according to claim 1, wherein a top of each of the plurality of second protrusions is located between two adjacent third protrusions. The distance along the normal direction of the first substrate between the tops of each of the adjacent second convex portions and the third convex portions is the distance between the tops of the adjacent second convex portions and the third convex portions. The light distribution control device according to claim 2, wherein the light distribution control device is 85% or more and less than 100% of a length along a normal direction of one substrate. 4. The adjacent second convex portion and third convex portion, wherein the third surface and the fifth surface are parallel, and the fourth surface and the sixth surface are parallel. 5. The light distribution control device as described in the above. The light distribution control device according to any one of claims 1 to 4, wherein the fourth surface and the sixth surface are orthogonal to the first direction. Each of the plurality of first protrusions, the plurality of second protrusions, and the plurality of third protrusions is an elongated protrusion extending along a second direction orthogonal to the first direction. The light distribution control device according to claim 1. The refractive index variable layer,
An insulating liquid;
The light distribution control device according to any one of claims 1 to 6, further comprising: a plurality of charged nanoparticles dispersed in the insulating liquid and having a different refractive index from the insulating liquid. An optical device, a light distribution control device including a light control film,
The optical device includes:
A first substrate having optical transparency;
A second substrate having a light-transmitting property, disposed opposite to the first substrate;
A light-transmitting first electrode layer and a second electrode layer disposed opposite to each other between the first substrate and the second substrate;
A light distribution layer disposed between the first electrode layer and the second electrode layer to distribute incident light;
The light distribution layer,
A first uneven structure layer having a plurality of first protrusions arranged side by side along the first direction;
A refractive index variable layer disposed so as to fill between the plurality of first convex portions, and a refractive index of which changes according to a voltage applied between the first electrode layer and the second electrode layer;
The light control film,
A second uneven structure layer having a plurality of second protrusions,
A third concavo-convex structure layer having a plurality of third protrusions disposed opposite to each of the plurality of second protrusions;
An air space located between the plurality of second protrusions and the plurality of third protrusions,
A light distribution rate of the light distribution control device is higher than 48%;
The light distribution control device, wherein the direct light rate of the light distribution control device is lower than 14%.

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