WO2018150663A1

WO2018150663A1 - Optical device

Info

Publication number: WO2018150663A1
Application number: PCT/JP2017/040735
Authority: WO
Inventors: 一樹北村; 伊藤　宜弘; 井出　伸弘
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-02-17
Filing date: 2017-11-13
Publication date: 2018-08-23
Also published as: JP2020064083A

Abstract

An optical device (1) equipped with a translucent first substrate (10), a translucent second substrate (20) that faces the first substrate (10), a light distribution layer (30) which distributes incident light and is positioned between the first substrate (10) and the second substrate (20), and a first electrode layer (40) and a second electrode layer (50) which are positioned so as to face one another with the light distribution layer (30) sandwiched therebetween, wherein: the light distribution layer (30) includes a relief structure layer (31) having a plurality of projecting sections (33), and also includes a variable refractive index layer (32) which is positioned so as to fill the intervals between the plurality of projecting sections (33), and in which the refractive index changes according to the voltage applied between the first electrode layer (40) and the second electrode layer (50); and the relief structure layer (31) includes a reinforcing layer (35) for reinforcing the intervals between the plurality of projecting sections (33).

Description

Optical device

The present invention relates to optical devices.

BACKGROUND Conventionally, a daylighting film is known that takes outside light such as sunlight incident from the outside into the room (see, for example, Patent Document 1). The daylighting film described in Patent Document 1 includes a daylighting layer laminated to a support layer. The light collection layer includes a plurality of transparent portions and a plurality of void portions disposed one by one between adjacent transparent portions, and reflects light at the interface between the transparent portion and the void portions.

WO 2016/088445

However, in the above conventional light collecting film, since the void is provided inside the light distribution layer, the strength is low. Moreover, since the optical state of the daylighting film is fixed in a state where the incident light is reflected, scattering of the incident light is increased and the transparency is lowered.

Then, an object of the present invention is to provide an optical device capable of switching an optical state and having an increased intensity.

In order to achieve the above object, an optical device according to an aspect of the present invention includes a light-transmitting first substrate, a light-transmitting second substrate facing the first substrate, and a light-transmitting second substrate. A light distribution layer disposed between the first base material and the second base material and configured to distribute incident light, and a first electrode layer and a second electrode layer disposed opposite to each other with the light distribution layer interposed therebetween; The light distribution layer includes a two-electrode layer, and the light distribution layer is disposed so as to fill the space between the plurality of projections and the concavo-convex structure layer having the plurality of projections, and between the first electrode layer and the second electrode layer. And a refractive index variable layer whose refractive index changes according to an applied voltage, and the uneven structure layer includes a reinforcing layer that reinforces between the plurality of convex portions.

According to the present invention, it is possible to provide an optical device capable of switching the optical state and having an increased intensity.

FIG. 1 is a cross-sectional view of an optical device according to an embodiment. FIG. 2 is an enlarged cross-sectional view of the optical device according to the embodiment. FIG. 3A is a diagram for describing an operation (light distribution state) when the optical device operates in the non-application mode when the optical device according to the embodiment is installed in a window. FIG. 3B is a diagram for describing an operation (a light transmitting state) when the optical device is operated in the voltage application mode when the optical device according to the embodiment is installed in the window. FIG. 4A is an enlarged sectional view for explaining a non-application mode (light distribution state) of the optical device according to the embodiment. FIG. 4B is an enlarged cross-sectional view for explaining a voltage application mode (light transmission state) of the optical device according to the embodiment. FIG. 5 is a view showing the relationship between the thickness ratio of the reinforcing layer of the optical device according to the embodiment and the haze.

Hereinafter, an optical device according to an embodiment of the present invention will be described in detail with reference to the drawings. Each embodiment described below shows one specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangements and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims indicating the highest concept of the present invention are described as optional components.

Further, each drawing is a schematic view, and is not necessarily illustrated exactly. Therefore, for example, the scale and the like do not necessarily match in each figure. Further, in each of the drawings, substantially the same configuration is given the same reference numeral, and overlapping description will be omitted or simplified.

Moreover, in the present specification and drawings, the x-axis, the y-axis and the z-axis indicate three axes of the 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. Moreover, in the present specification, the “thickness direction” means the thickness direction of the optical device, and is a direction perpendicular to the main surfaces of the first base and the second base, “plan view” When it sees from the direction perpendicular to the principal surface of the 1st substrate or the 2nd substrate.

Embodiment
[Constitution]
First, the configuration of the optical device 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of an optical device 1 according to the present embodiment. FIG. 2 is an enlarged cross-sectional view of the optical device 1 according to the present embodiment, and is an enlarged cross-sectional view of a region II surrounded by an alternate long and short dash line in FIG.

The optical device 1 is a light control device that controls light incident on the optical device 1. Specifically, the optical device 1 is a light distribution element capable of changing the traveling direction of light incident on the optical device 1 (that is, distributing light) and causing the light to be emitted.

As shown in FIGS. 1 and 2, the optical device 1 is configured to transmit incident light, and includes a first base 10, a second base 20, a light distribution layer 30, and a first light. An electrode layer 40 and a second electrode layer 50 are provided.

An adhesion layer may be provided on the surface of the first electrode layer 40 on the light distribution layer 30 side in order to bring the first electrode layer 40 into close contact with the uneven structure layer 31 of the light distribution layer 30. The adhesion layer is, for example, a translucent adhesive sheet, or a resin material generally referred to as a primer.

In the optical device 1, the first electrode layer 40, the light distribution layer 30, and the second electrode layer 50 are disposed in this order along the thickness direction between the first base material 10 and the second base material 20 forming a pair. Configuration. In addition, in order to maintain the distance between the first base material 10 and the second base material 20, a plurality of particulate spacers may be dispersed in a plane, and a columnar structure may be formed. .

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

[First base and second base]
The first base 10 and the second base 20 are translucent substrates having translucency. For example, a glass substrate or a resin substrate can be used as the first base 10 and the second base 20.

Examples of the material of the glass substrate include soda glass, alkali-free 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) or 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 breakage is small.

The first base 10 and the second base 20 may be made of the same material, or may be made of different materials. Moreover, the 1st base material 10 and the 2nd base material 20 are not restricted to a rigid board | substrate, You may be a flexible substrate which has flexibility. In the present embodiment, the first base 10 and the second base 20 are transparent resin substrates made of PET resin.

The second base material 20 is an opposing base material facing the first base material 10 and is disposed at a position facing the first base material 10. The first base 10 and the second base 20 are disposed substantially in parallel at a predetermined distance such as 10 μm to 30 μm, for example. The first base material 10 and the second base material 20 are bonded by a sealing resin such as an adhesive formed in the shape of a frame on the outer periphery of each end.

In addition, although the planar view shape of the 1st base material 10 and the 2nd base material 20 is rectangular shapes, such as a square or a rectangle, for example, it does not restrict to this, Even if it is polygons other than a circle or a square Well, any shape may be employed.

[Light distribution layer]
As shown in FIGS. 1 and 2, the light distribution layer 30 is disposed between the first base 10 and the second base 20. The light distribution layer 30 has translucency, and transmits incident light. In addition, the light distribution layer 30 distributes the incident light. That is, when 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 has a concavo-convex structure layer 31 and a refractive index variable layer 32. The light distribution layer 30 can distribute light by the difference in refractive index between the uneven structure layer 31 and the refractive index variable layer 32.

[Uneven structure layer]
The uneven structure layer 31 is a fine shape layer provided to make the surface (interface) of the variable-refractive-index layer 32 uneven. The uneven structure layer 31 has a plurality of convex portions 33 and a plurality of concave portions 34, as shown in FIG. Specifically, the concavo-convex structure layer 31 is a concavo-convex structure constituted by a plurality of convex portions 33 of micro order size. A plurality of concave portions 34 are between the plurality of convex portions 33. That is, one concave portion 34 is between two adjacent convex portions 33.

The plurality of protrusions 33 are a plurality of protrusions arranged in the z-axis direction (first direction) parallel to the main surface of the first base material 10 (the surface on which the first electrode layer 40 is provided). . That is, in the present embodiment, the z-axis direction is the direction in which the plurality of convex portions 33 are arranged.

Each of the plurality of projections 33 has a tapered shape from the root to the tip. In the present embodiment, the cross-sectional shape of each of the plurality of projections 33 is a tapered shape that tapers along the direction (thickness direction, y-axis positive direction) from the first base material 10 toward the second base material 20 . Although the cross-sectional shape (yz cross section) of the convex part 33 is a trapezoid specifically, it is not restricted to this. The cross-sectional shape of the convex portion 33 may be a triangle, another polygon, or a polygon including a curve. Further, although the tip of the convex portion 33 is in contact with the second electrode layer 50, a gap may be provided between the tip of the convex portion 33 and the second electrode layer 50. In this case, the gap is filled with the variable-refractive-index layer 32.

As shown in FIG. 2, each of the plurality of protrusions 33 has a pair of side surfaces 33 a and 33 b facing the recess 34. The pair of

side surfaces

33a and 33b are surfaces intersecting in the z-axis direction. Each of the pair of

side surfaces

33a and 33b is an inclined surface which is inclined at a predetermined inclination angle with respect to the thickness direction (y-axis direction), and the distance between the pair of

side surfaces

33a and 33b (the width of the convex portion 33 (z-axis direction ) Is gradually reduced from the first base 10 to the second base 20.

The side surface 33 a is, for example, a side surface (lower side surface) on the vertically lower side among a plurality of side surfaces constituting the convex portion 33. The side surface 33a is a refractive surface that refracts incident light. The side surface 33 b is, for example, a side surface (upper side surface) on the vertically upper side among a plurality of side surfaces constituting the convex portion 33. The side surface 33 b is a reflection surface (total reflection surface) that reflects incident light (total reflection).

In the present embodiment, the plurality of convex portions 33 are formed in a stripe shape extending in the x-axis direction. That is, each of the plurality of convex portions 33 is a long convex portion linearly extending along the x-axis direction. Specifically, each of the plurality of convex portions 33 has a trapezoidal cross-sectional shape and is an elongated substantially square pole shape extending in the x-axis direction, and is arranged at substantially equal intervals along the z-axis direction There is. Each of the plurality of protrusions 33 has the same shape, but may have different shapes.

The height H (the length in the y-axis direction) of each of the plurality of protrusions 33 is, for example, 2 μm to 100 μm, but is not limited thereto. In addition, height H of the convex part 33 is corresponded to the length of the part which protruded in the thickness direction from the reinforcement layer 35, as shown in FIG. The width W (length in the z-axis direction) of the plurality of protrusions 33 is, for example, 1 μm to 20 μm, and preferably 10 μm or less, but not limited thereto. The width P (z-axis direction) of the recess 34 is, for example, 0 μm to 100 μm. That is, the two adjacent convex portions 33 may be disposed at a predetermined distance without contacting with each other, or may be disposed in contact with each other. The distance between the adjacent convex portions 33 is not limited to 0 μm to 100 μm.

In the present embodiment, the aspect ratio of the convex portion 33 is 2 or more. The aspect ratio of the convex portion 33 is the height H of the convex portion 33 with respect to the width W at the root of the convex portion 33. As shown in FIG. 2, the cross-sectional shape of the convex portion 33 is elongated in the thickness direction.

In the present embodiment, as shown in FIG. 2, the concavo-convex structure layer 31 includes a reinforcing layer 35 that reinforces between the plurality of convex portions 33. The reinforcing layer 35 connects between the plurality of convex portions 33. That is, the reinforcing layer 35 connects the roots of the adjacent convex portions 33 and is provided so as to fill the bottom of the concave portion 34. Specifically, the reinforcing layer 35 is formed in a stripe shape extending in the x-axis direction, similarly to the convex portion 33.

In the present embodiment, since the reinforcing layer 35 is provided at the bottom of the recess 34, the variable-refractive-index layer 32 is not in contact with the first electrode layer 40 or the first base material 10. The reinforcing layer 35 may be provided discretely, such as in the form of dots, and in this case, the gap between the reinforcing layers 35 may be filled with a liquid crystal material or the like constituting the refractive index variable layer 32. .

Assuming that the thickness of the reinforcing layer 35 is T and the height of the projections 33 is H, the thickness ratio of the reinforcing layer 35 is expressed by T / (T + H). In the present embodiment, the thickness ratio T / (T + H) is 0.5 or less. That is, the thickness T of the reinforcing layer 35 is equal to or less than half the height H of the convex portion 33. For example, although thickness T of reinforcement layer 35 is 2 micrometers, it is not restricted to this.

In the present embodiment, the reinforcing layer 35 and the plurality of convex portions 33 are formed using the same material. That is, the reinforcing layer 35 and the plurality of convex portions 33 are integrally formed.

As a material of the convex part 33 and the reinforcement layer 35, the resin material which has light transmittances, such as an acrylic resin, an epoxy resin, or a silicone resin, can be used, for example. The convex portion 33 and the reinforcing layer 35 are formed of, for example, an ultraviolet curable resin material, and can be formed by molding or nanoimprinting.

The concavo-convex structure layer 31 can form the concavo-convex structure whose cross section has a trapezoidal shape by mold pressing, for example, using an acrylic resin having a refractive index of 1.5. The height of the projections 33 is, for example, 10 μm, and the plurality of projections 33 are arranged at equal intervals of 2 μm in the z-axis direction at equal intervals. The thickness of the root of the convex portion 33 is 5 μm, for example. The distance between the roots of adjacent convex portions 33 can take, for example, a value of 0 μm to 5 μm.

[Refractive index variable layer]
The refractive index variable layer 32 is disposed so as to fill the gaps 34 between the plurality of convex portions 33 of the uneven structure layer 31. 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.

The refractive index of the variable-refractive-index layer 32 changes in accordance with 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 whose refractive index in the visible light band can be adjusted by application of an electric field. For example, since the variable-refractive-index layer 32 is formed of liquid crystal having liquid crystal molecules 36 having electric field responsiveness, application of an electric field to the light distribution layer 30 changes the alignment state of the liquid crystal molecules 36 to change the refractive index. The refractive index of the variable layer 32 changes.

The birefringent material of the refractive index variable layer 32 is, for example, a liquid crystal including liquid crystal molecules 36 having birefringence. As such a liquid crystal, for example, nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, or the like in which liquid crystal molecules 36 are rod-like molecules can be used. For example, when the refractive index of the convex portion 33 is 1.5, as a material of the refractive index variable layer 32, an ordinary light refractive index (no) is 1.5 and an extraordinary light refractive index (ne) is 1.7 A positive liquid crystal can be used.

The refractive index variable layer 32 is, for example, an end portion of each of the first base material 10 on which the first electrode layer 40 and the concavo-convex structure layer 31 are formed, and the second base material 20 on which the second electrode layer 50 is formed. It is formed by injecting a liquid crystal material by a vacuum injection method in a state where the outer periphery is sealed with a sealing resin. Alternatively, the refractive index variable layer 32 may be formed by dropping the liquid crystal material onto the first electrode layer 40 and the concavo-convex structure layer 31 of the first base material 10 and then bonding the second base material 20 together.

Note that FIG. 2 shows a state in which no voltage is applied (the same applies to FIG. 4A described later), and the liquid crystal molecules 36 are aligned such that the major axis is substantially parallel to the x axis. When a voltage is applied between the first electrode layer 40 and the second electrode layer 50, the liquid crystal molecules 36 are aligned so that the major axis is substantially parallel to the y axis (see FIG. 4B described later) ).

Further, an electric field may be applied to the refractive index variable layer 32 by AC power, and an electric field may be applied by DC power. In the case of AC power, the voltage waveform may be a sine wave or a square wave.

[First electrode layer and second electrode layer]
As shown in FIGS. 1 and 2, the first electrode layer 40 and the second electrode layer 50 are electrically paired and configured to be able to apply an electric field to the light distribution layer 30. The first electrode layer 40 and the second electrode layer 50 are not only electrically but also arranged in a pair, so as to face each other between the first base material 10 and the second base material 20. It is arranged. Specifically, the first electrode layer 40 and the second electrode layer 50 are disposed to sandwich the light distribution layer 30.

The first electrode layer 40 and the second electrode layer 50 have translucency and transmit incident light. The first electrode layer 40 and the second electrode layer 50 are, for example, transparent conductive layers. The material of the transparent conductive layer is a transparent metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), a conductor containing resin made of a resin containing a conductor such as silver nanowire or conductive particles, or And metal thin films such as silver thin films can be used. The first electrode layer 40 and the second electrode layer 50 may have a single-layer structure of these, or a laminated structure of these (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 disposed between the first base 10 and the uneven structure layer 31. Specifically, the first electrode layer 40 is formed on the surface of the first base material 10 on the light distribution layer 30 side.

On the other hand, the second electrode layer 50 is disposed between the refractive index variable layer 32 and the second base material 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, for example, to enable electrical connection with an external power supply. For example, an electrode pad or the like for connection to an external power source may be drawn out from each of the first electrode layer 40 and the second electrode layer 50 and formed on the first base 10 and the second base 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 or sputtering.

[Optical state of optical device]
Subsequently, the optical state (operation mode) of the optical device 1 will be described while showing an example of use of the optical device 1 according to the present embodiment. Specifically, an optical system including the optical device 1 will be described with reference to FIGS. 3A and 3B.

FIGS. 3A and 3B each show an example in which an optical system 60 including the optical device 1 according to the present embodiment is applied to a building 90. FIG. Specifically, FIGS. 3A and 3B are diagrams for explaining the operation when the optical device 1 is operated in each operation mode when the optical device 1 is installed in the window 91.

As shown in FIGS. 3A and 3B, the optical system 60 includes the optical device 1 and a controller 61. In each of the drawings, the shaded area of the dot extending from the optical device 1 indicates the area through which the light (specifically, the S polarization component) which has passed through the optical device 1 passes.

The optical device 1 can transmit incident light. For example, by installing the optical device 1 in the window 91 of the building 90, it can be realized as a window with a light distribution function. The optical device 1 is bonded, for example, to the existing window 91 via the adhesive layer. In this case, the optical device 1 is installed in the window 91 such that the main surfaces of the first base 10 and the second base 20 are parallel to the vertical direction (z-axis direction).

Although the detailed structure of the optical device 1 is not shown in FIGS. 3A and 3B, in the optical device 1, the first base 10 is on the outdoor side, the second base 20 is on the indoor side, and The side surface 33 b of the convex portion 33 is disposed on the ceiling 92 side and the side surface 33 a is on the floor 93 side.

Moreover, although the control part 61 is installed on the floor 93, this is illustrated typically and it is not specifically limited to the installation place of the control part 61. FIG. For example, the control unit 61 may be integrally formed with the optical device 1 and may be fixed to a window frame of the window 91 or the like. Alternatively, the control unit 61 may be embedded in the ceiling 92, the floor 93 or a wall of the building 90.

The control unit 61 is a control unit that drives the optical device 1. Specifically, the control unit 61 applies an electric field to the light distribution layer 30 by applying a predetermined voltage between the first electrode layer 40 and the second electrode layer 50.

In the present embodiment, control unit 61 has two operation modes according to the application state of the voltage between first electrode layer 40 and second electrode layer 50. Specifically, the two operation modes are a non-application mode (first operation mode) in which no voltage is applied and a voltage application mode (second operation mode) in which a voltage is substantially uniformly applied between the electrode layers. The control unit 61 switches and executes two operation modes based on user operation or predetermined schedule information.

In the optical device 1, the orientation of the liquid crystal molecules 36 contained in the refractive index variable layer 32 changes in accordance with the electric field applied to the light distribution layer 30. Since the liquid crystal molecules 36 are rod-like liquid crystal molecules having birefringence, the refractive index that the light receives varies depending on the polarization state of the incident light. Here, for example, for incident light, the refractive index of the convex portion 33 is 1.5, and as the liquid crystal molecules 36, the ordinary light refractive index (no) is 1.5 and the extraordinary light refractive index (ne) is The case of a positive-type liquid crystal molecule of 1.7 will be described as an example.

Light such as sunlight incident on the optical device 1 includes P-polarization (P-polarization component) and S-polarization (S-polarization component). The vibration direction of the P-polarized light is substantially parallel to the short axis of the liquid crystal molecule 36 in either the non-application mode or the voltage application mode. For this reason, the refractive index of the liquid crystal molecules 36 for P-polarization does not depend on the operation mode, and is the ordinary refractive index (no), specifically 1.5. For this reason, the refractive index for P-polarization does not depend on the operation mode and becomes substantially constant in the light distribution layer 30, so the P-polarization goes straight through the light distribution layer 30 as it is.

On the other hand, the refractive index of the liquid crystal molecules 36 for S-polarization changes in accordance with the operation mode.

Specifically, when driven in the non-application mode, the optical device 1 is in a light distribution state in which the traveling direction of incident light (S polarization) is changed. When driven in the voltage application mode, the optical device 1 is in a light transmitting (transparent) state that allows incident light (S-polarized light) to pass as it is (without changing the traveling direction).

Hereinafter, details of each operation mode will be described using FIGS. 4A and 4B with reference to FIGS. 3A and 3B as appropriate. FIG. 4A and FIG. 4B are each an enlarged sectional view for explaining each operation mode of the optical device 1 according to the present embodiment.

In FIGS. 4A and 4B, paths of light L (for example, sunlight) incident on the optical device 1 are indicated by thick arrows. Note that, in fact, the light L is refracted when entering the first base material 10 and exiting from the second base material 20, but the change of the path due to the refraction is not shown.

<No-application mode (light distribution state)>
FIG. 4A schematically shows the state of the optical device 1 when driven in the non-application mode and the path of the light L passing through the optical device 1.

The control unit 61 does not apply a voltage between the first electrode layer 40 and the second electrode layer 50 when operating the optical device 1 in the non-application mode. Specifically, when the first electrode layer 40 and the second electrode layer 50 have substantially the same potential (for example, the ground potential), no electric field is applied to the light distribution layer 30. Therefore, the refractive index of the refractive index variable layer 32 can be made substantially uniform in the plane.

In this case, the refractive index received by the light L (S-polarized light) is 1.5 for the convex portion 33, while the refractive index variable layer 32 is 1.7. Therefore, as shown in FIG. 4A, the light L incident obliquely to the optical device 1 is refracted by the side surface 33a of the convex portion 33 and then reflected (totally reflected) by the side surface 33b. The light reflected by the side surface 33 b is emitted obliquely upward. That is, the optical device 1 emits the light L incident obliquely downward toward the obliquely upward.

Therefore, as shown in FIG. 3A, the light L such as sunlight incident obliquely downward is bent in its traveling direction by the optical device 1 and illuminates the ceiling 92 of the building 90.

<Voltage application mode (light transmission state)>
FIG. 4B schematically shows the state of the optical device 1 when driven in the voltage application mode and the path of the light L passing through the optical device 1.

The control unit 61 applies a predetermined voltage between the first electrode layer 40 and the second electrode layer 50 when operating the optical device 1 in the voltage application mode. Thereby, the electric field applied to the light distribution layer 30 becomes substantially uniform in the plane, and the refractive index of the refractive index variable layer 32 can be made substantially uniform in the plane.

In this case, the refractive index received by the light L (S polarized light) is 1.5 for both the convex portion 33 and the refractive index variable layer 32. Therefore, as shown in FIG. 4B, the light L obliquely incident on the optical device 1 passes through the optical device 1 as it is. That is, the optical device 1 emits the light L incident obliquely downward as it is downward. Therefore, as shown to FIG. 3B, light L, such as sunlight which enters diagonally downward, passes the optical device 1 as it is, and irradiates the part near the window 91 of the floor 93 of the building 90. As shown in FIG.

As described above, according to the optical device 1 according to the present embodiment, it is possible to use the optical device according to the electric field applied to the light distribution layer 30 (the voltage applied between the first electrode layer 40 and the second electrode layer 50). It is possible to change the state. Here, although the light transmission state and the light distribution state are switched, it is possible to form an intermediate optical state between the light distribution state and the light transmission state according to the applied voltage.

For example, in the voltage application mode, a plurality of voltage levels to be applied may be set and switching may be performed as appropriate. In the voltage application mode, by reducing the voltage to be applied, the angle of light distribution by the optical device 1 is smaller in the intermediate optical state than in the light distribution state. For example, light can travel to the far side of the interior of the building 90.

[Relation between thickness of reinforcing layer and haze]
As described above, in the optical device 1 according to the present embodiment, the light distribution state and the light transmission (transparent) state can be switched. For this reason, in the transparent state, it is required that the transparency of the optical device 1 be sufficiently high. On the other hand, when the strength of the convex portion 33 is weak and the shape of the convex portion 33 is broken, the light distribution efficiency is lowered. Therefore, it is required to maintain the strength of the convex portion 33 while enhancing the transparency of the optical device 1 in the transparent state.

In the present embodiment, in order to increase the strength of the convex portion 33 of the concavo-convex structure layer 31, the reinforcing layer 35 is provided. As the thickness T of the reinforcing layer 35 is increased, the strength of the convex portion 33 can be enhanced.

On the other hand, as the thickness T of the reinforcing layer 35 becomes larger, the partial pressure of the voltage applied between the first electrode layer 40 and the second electrode layer 50 to the reinforcing layer 35 becomes larger. Therefore, the electric field applied to the refractive index variable layer 32 becomes small, and the liquid crystal molecules 36 are difficult to be properly aligned. If the orientation of the liquid crystal molecules 36 becomes insufficient, the refractive index within the light distribution layer 30 will not be uniform, and light scattering will occur. For this reason, the transparency of the optical device 1 is reduced.

FIG. 5 is a view showing the relationship between the thickness ratio of the reinforcing layer 35 of the optical device 1 according to the present embodiment and the haze. In FIG. 5, the horizontal axis indicates the thickness ratio T / (T + H) of the reinforcing layer 35, and the vertical axis indicates the haze [%] in the light transmission (transparent) state of the optical device 1.

The haze is a parameter indicating the transparency of the optical device 1. As the haze is smaller, the optical device 1 is more transparent, and as the haze is larger, the optical device 1 looks more cloudy.

As shown in FIG. 5, as the thickness ratio of the reinforcing layer 35 is smaller, the haze is smaller and the optical device 1 becomes closer to transparent. For example, when the thickness ratio is 0.5, the haze is about 11%. When the haze is larger than about 11%, the turbidity when the optical device 1 is in the transparent state is easily noticeable. For this reason, in the optical device 1 according to the present embodiment, by setting the thickness ratio to 0.5 or less, the haze can be reduced and the transparency of the optical device 1 in the transparent state can be increased.

Further, the haze is approximately the same at about 6 to 7% when the thickness ratio is 0.15 and 0.25. When the thickness ratio is too small, the strength of the convex portion 33 becomes weak. Therefore, the thickness ratio may be, for example, 0.15 or more or 0.25 or more.

[Effect, etc.]
As described above, the optical device 1 according to the present embodiment includes the light-transmitting first base material 10, the second base material 20 facing the first base material 10, and the light-transmitting property, A light distribution layer 30 disposed between the first base material 10 and the second base material 20 for distributing incident light, and a first electrode layer 40 disposed opposite to each other with the light distribution layer 30 interposed therebetween. And a second electrode layer 50. The light distribution layer 30 is disposed so as to fill the space between the plurality of convex portions 33 with the uneven structure layer 31 having the plurality of convex portions 33, and a voltage applied between the first electrode layer 40 and the second electrode layer 50. And the variable-refractive-index layer 32 whose refractive index changes according to. The uneven structure layer 31 includes a reinforcing layer 35 that reinforces between the plurality of convex portions 33.

Thereby, the refractive index of the refractive index variable layer 32 changes in accordance with the voltage applied between the first electrode layer 40 and the second electrode layer 50, so that the optical state of the optical device 1 can be changed. For example, by making the refractive index of the refractive index variable layer 32 substantially equal to the refractive index of the concavo-convex structure layer 31, the optical device 1 can be made to be in a light transmitting (transparent) state. Further, by making the refractive index of the refractive index variable layer 32 different from the refractive index of the concavo-convex structure layer 31, it is possible to make a light distribution state in which light is reflected by the side surface 33b and emitted in a predetermined direction. Thus, according to the optical device 1 according to the present embodiment, the optical state can be changed.

Furthermore, as shown in FIGS. 3A and 3B and the like, the optical device 1 is used by being attached to, for example, a window 91 or the like. At this time, in order to prevent a gap (bubble) from being formed between the optical device 1 and the window 91, the optical device 1 is strongly pressed against the window 91 using a jig or the like to release the bubble to the outside. Is done. In the optical device 1 according to the present embodiment, since the reinforcing layer 35 for reinforcing between the plurality of convex portions 33 is provided, even when a strong force is applied from the outside, It is possible to suppress the collapse of the shape.

As described above, according to the present embodiment, it is possible to realize the optical device 1 capable of switching the optical state and enhancing the intensity.

Further, for example, when the thickness of the reinforcing layer 35 is T and the height of the projections 33 is H, T / (T + H), which is the thickness ratio of the reinforcing layer 35, is 0.5 or less.

Thereby, since the thickness ratio is 0.5 or less, the haze when the optical device 1 is in the transparent state can be made smaller than about 11%. Therefore, the transparency of the optical device 1 can be increased.

Further, for example, the aspect ratio indicating the height H to the width W at the root of the convex portion 33 is 2 or more.

Since the aspect ratio of the convex part 33 is two or more by this, the side surface 33b which functions as a reflective surface of light can be enlarged, and light distribution can be increased. On the other hand, when the aspect ratio of the convex portion 33 is increased, the force from the outside is weakened. For this reason, the reinforcing effect by the reinforcing layer 35 is more effectively exhibited.

Further, for example, the reinforcing layer 35 and the plurality of convex portions 33 are formed using the same material.

Thereby, for example, since it can form integrally by nanoimprint, molding, etc., a manufacturing process can be simplified. In addition, since the convex portion 33 and the reinforcing layer 35 are integrally formed, the stress applied to the convex portion 33 can be efficiently dissipated to the reinforcing layer 35, so that the reinforcing effect can be further enhanced.

Further, for example, the reinforcing layer 35 connects between the plurality of convex portions 33.

As a result, by connecting the reinforcing layers 35 between adjacent convex portions 33, stress applied to the convex portions 33 can be efficiently released to the reinforcing layer 35. Further, since the adhesion area between the reinforcing layer 35 and the first electrode layer 40 is also increased, the adhesion strength between the uneven structure layer 31 and the first electrode layer 40 can also be enhanced. Therefore, the reinforcing effect can be further enhanced.

(Others)
As mentioned above, although the optical device concerning the present invention was explained based on the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment.

For example, the reinforcing layer 35 may not connect two adjacent convex portions 33 to each other. That is, the reinforcing layer 35 may be provided for each of the convex portions 33 and may be formed in a bowl shape protruding laterally (z-axis direction) from the root. For example, between the reinforcing layer 35 provided on the side surface 33 a side of one of the two adjacent convex portions 33 and the reinforcing layer 35 provided on the other side surface 33 b side of the two adjacent convex portions 33, A gap may be provided. The gap may be filled with a liquid crystal material constituting the refractive index variable layer 32.

Also, for example, the reinforcing layer 35 may be formed separately from the convex portion 33. Specifically, the reinforcing layer 35 may be formed using a material different from that of the convex portion 33.

Also, for example, in the above embodiment, the optical device is disposed in the window so that the longitudinal direction of the convex portion 33 is the x-axis direction, but the present invention is not limited to this. For example, the optical device may be disposed in the window such that the longitudinal direction of the convex portion 33 is the z-axis direction.

Further, for example, in the above-described embodiment, each of the plurality of convex portions 33 constituting the concavo-convex structure layer 31 has a long shape, but the present invention is not limited to this. For example, the plurality of convex portions 33 may be arranged to be dispersed in a matrix or the like. That is, the plurality of convex portions 33 may be arranged in a dotted manner. In this case, the reinforcing layer 35 may also be provided in a dot shape for each convex portion 33.

Further, for example, in the above-described embodiment, each of the plurality of convex portions 33 has the same shape. However, the present invention is not limited thereto. For example, the shapes may be different in the plane. For example, the inclination angles of the side surfaces 33a or 33b of the plurality of protrusions 33 may be different between the upper half and the lower half in the z-axis direction of the optical device 1.

Further, for example, in the above embodiment, the heights of the plurality of convex portions 33 are fixed, but the present invention is not limited to this. For example, the heights of the plurality of protrusions 33 may be randomly different. By doing this, it is possible to suppress that the light transmitted through the optical device appears iridescent. That is, by randomly changing the heights of the plurality of convex portions 33, minute diffracted light and scattered light at the concavo-convex interface are averaged by the wavelength, and coloring of the emitted light is suppressed.

Moreover, although sunlight was illustrated as light which injects into the optical device 1 in said embodiment, it does not restrict to this. For example, the light incident on the optical device 1 may be light emitted by a light emitting device such as a lighting device.

In the above embodiment, the optical device 1 is attached to the indoor surface of the window 91. However, the optical device 1 may be attached to the outdoor surface of the window 91. By sticking on the indoor side, deterioration of the optical element can be suppressed. Further, although the optical device 1 is attached to the window 91, the optical device may be used as the window of the building 90 itself. Further, the optical device 1 is not limited to being installed in the window 91 of the building 90, and may be installed in, for example, a window of a car.

Note that these modifications can be applied to other embodiments and modifications.

In addition, the present invention can be realized by arbitrarily combining components and functions in each embodiment without departing from the scope of the present invention or embodiments obtained by applying various modifications that those skilled in the art may think to each embodiment. The form is also included in the present invention.

DESCRIPTION OF SYMBOLS 1 optical device 10 1st base material 20 2nd base material 30 light distribution layer 31 concavo-convex structure layer 32 refractive index variable layer 33 convex part 35 reinforcement layer 40 1st electrode layer 50 2nd electrode layer

Claims

A translucent first substrate,
A light transmitting second substrate facing the first substrate;
A light distribution layer disposed between the first base and the second base for distributing incident light;
And a first electrode layer and a second electrode layer disposed opposite to each other with the light distribution layer interposed therebetween,
The light distribution layer is
An uneven structure layer having a plurality of convex portions,
And a refractive index variable layer which is disposed so as to fill the spaces between the plurality of convex portions and whose refractive index changes according to a voltage applied between the first electrode layer and the second electrode layer,
The uneven structure layer includes a reinforcing layer that reinforces between the plurality of convex portions. Optical device.
The thickness ratio of the reinforcing layer, T / (T + H), is 0.5 or less, where T is the thickness of the reinforcing layer and H is the height of the convex portion. device.
The optical device according to claim 1, wherein an aspect ratio indicating a height to a width at a root of the convex portion is 2 or more.
The optical device according to any one of claims 1 to 3, wherein the reinforcing layer and the plurality of convex portions are formed using the same material.
The optical device according to any one of claims 1 to 4, wherein the reinforcing layer connects between the plurality of convex portions.