WO2024070909A1

WO2024070909A1 - Optical device, optical member, and light guide member

Info

Publication number: WO2024070909A1
Application number: PCT/JP2023/034395
Authority: WO
Inventors: 真平百足山; 宇峰翁; 恒三中村
Original assignee: 日東電工株式会社
Priority date: 2022-09-27
Filing date: 2023-09-22
Publication date: 2024-04-04
Also published as: JP2024048153A

Abstract

An optical member (100) comprises: a light guide block column in which a plurality of light guide blocks (10A) are arranged along a light guide direction, each light guide block including a first light guide block having a light receiving surface, an emission surface on the reverse side from the light receiving surface, and at least three side surfaces between the light receiving surface and the emission surface, and having a light diffusing structure formed on the light receiving surface or a second light guide block having the light diffusing structure formed on the emission surface; and a light extraction layer disposed on a side surface of the first light guide block or a light extraction layer disposed on a side surface of a light guide block disposed on the emission surface side of the second light guide block.

Description

Optical device, optical member, and light-guiding member

The present invention relates to an optical device, an optical member, and a light-guiding member.

In recent years, a variety of optical devices have been developed that use LED elements as light sources. Among these are optical devices that have a light source and multiple light-guiding layers.

For example, Patent Document 1 discloses a backlight unit having multiple light guide layers. Patent Document 2 discloses a display device having multiple light guide layers.

JP 2011-23353 A Japanese Patent Application Laid-Open No. 9-212116

　Conventional optical devices such as those described in Patent Documents 1 and 2 are optical devices of a predetermined size, and it is not assumed that the user will be able to change the size.

The present invention aims to provide an optical device that can provide completely new usage patterns, for example by allowing the user to easily change the size, and optical members and light-guiding members used in such an optical device.

According to an embodiment of the present invention, the following solutions are provided:
[Item 1]
at least one light guide block row in which a plurality of light guide blocks are arranged along a light guide direction, each of the plurality of light guide blocks having a light receiving surface, an emission surface opposite to the light receiving surface, and at least three side surfaces between the light receiving surface and the emission surface, the at least one light guide block row including a first light guide block having a light diffusion structure formed on the light receiving surface or a second light guide block having a light diffusion structure formed on the emission surface;
a light extraction layer disposed on at least one of the at least three side surfaces of the first light guide block, or a light extraction layer disposed on at least one of the at least three side surfaces of a light guide block disposed on the exit surface side of the second light guide block.
[Item 2]
2. The optical member according to claim 1, wherein the light diffusion structure is a concave-convex structure formed on the light receiving surface or the light emitting surface.
[Item 3]
3. The optical member according to claim 2, wherein the uneven structure is a fine uneven structure formed by roughening the light receiving surface or the light emitting surface.
[Item 4]
Item 4. The optical member according to item 3, wherein the fine uneven structure has an average roughness Ra of 1.6 μm or more and 100 μm or less.
[Item 5]
5. The optical member according to any one of items 1 to 4, wherein the plurality of light guide blocks in the at least one row of light guide blocks include a light guide block that does not have a light extraction layer on the at least three side surfaces.
[Item 6]
6. The optical element according to any one of items 1 to 5, wherein the light extraction layer has a plurality of internal spaces that extract light by total internal reflection.
[Item 7]
7. The optical member according to any one of claims 1 to 6, wherein the light guiding block has a substantially rectangular parallelepiped shape.
[Item 8]
8. The optical member according to any one of items 1 to 7, wherein the at least one row of light guide blocks includes a plurality of rows of light guide blocks arranged in parallel.
[Item 9]
The optical member according to claim 1 , wherein the at least one row of light guiding blocks further comprises an adhesive layer disposed on the light diffusing structure.
[Item 10]
10. The optical member according to any one of items 1 to 9,
a light source arranged to emit light toward the plurality of light guide block rows.
[Item 11]
a light guiding block having a light receiving surface, an emission surface opposite the light receiving surface, and at least three side surfaces between the light receiving surface and the emission surface;
a light extraction layer disposed on at least one of the at least three sides;
a light-diffusing adhesive layer disposed on at least one of the light-receiving surface and the light-emitting surface.

Embodiments of the present invention provide an optical device that allows the user to easily change the size, enabling completely new forms of use, as well as light-guiding members and optical members that are suitable for use with such optical devices.

FIG. 1 is a schematic perspective view of an optical member 100A according to an embodiment of the present invention. 1 is a schematic perspective view of a light guide member 10M1 included in an optical member 100A. FIG. 1 is a schematic partial cross-section of a portion including a light receiving surface RS of a light guide block 10A of an optical member 100A. 1 is a schematic partial cross-sectional view of a portion including a light extraction layer 20 of a light guide member 10M1. FIG. FIG. 11 is a schematic perspective view of an optical member 100B according to another embodiment of the present invention. FIG. 11 is a schematic perspective view of an optical member 100C according to still another embodiment of the present invention. FIG. 11 is a schematic perspective view of an optical member 100D according to still another embodiment of the present invention. FIG. 1 is a schematic perspective view of an optical device 1000 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a light extraction film 200 used in manufacturing an optical member according to an embodiment of the present invention. FIG. 2 is a schematic plan view of a light extraction film 200. 2 is a schematic cross-sectional view of an internal space 24. FIG. FIG. 2 is a schematic plan view of the internal space 24. FIG. 2 is a schematic perspective view of a light-guiding member 10M2 according to an embodiment of the present invention. 1 is an optical image of a prototype optical component. 13 is an optical image of another prototype optical member. 13 is an optical image of yet another prototype optical member. 13 is an optical image of yet another prototype optical member.

Below, optical devices, optical members, and light-guiding members according to embodiments of the present invention will be described with reference to the drawings. The optical devices, optical members, and light-guiding members according to embodiments of the present invention are not limited to those exemplified below.

The optical member according to an embodiment of the present invention has at least one light guide block row in which a plurality of light guide blocks are arranged along the light guide direction, and each of the plurality of light guide blocks has a light receiving surface, an exit surface opposite to the light receiving surface, and at least three side surfaces between the light receiving surface and the exit surface. The optical member has at least one light guide block row including a first light guide block (see light guide block 10A in FIG. 1) having a light diffusion structure formed on the light receiving surface, or a second light guide block (see light guide block 10B in FIG. 6) having a light diffusion structure formed on the exit surface, and a light extraction layer disposed on at least one of the at least three side surfaces of the first light guide block, or a light extraction layer disposed on at least one of the at least three side surfaces of the light guide block disposed on the exit surface side of the second light guide block. The optical device according to the embodiment of the present invention is obtained by arranging a light source so as to emit light toward the light guide block row. Of course, the light guide block may have a light diffusion structure formed on both the exit surface and the light receiving surface.

For example, the size of the optical device can be easily changed by changing the number of light guide blocks constituting a light guide block row and/or by changing the number of light guide block rows. The optical device can be used, for example, as a lighting device or a display device. By changing the arrangement of the light guide block rows, lighting devices of various shapes can be obtained. Also, for example, a display device having multiple light guide block rows arranged in parallel can perform dot display, with each light guide block serving as one dot. Also, light guide blocks of various sizes or shapes can be combined.

The structure and operation of an optical element 100A according to an embodiment of the present invention will be described with reference to Figures 1 to 4. An example having a light guide block that is approximately rectangular parallelepiped will be described below, but the light guide block may be, for example, a triangular prism or a polygonal prism having pentagonal or higher sides. The shape of the light guide block may also be, for example, a rectangular prism with chamfered edges.

First, let us refer to Fig. 1 and Fig. 2. Fig. 1 shows a schematic perspective view of an optical member 100A according to an embodiment of the present invention, and Fig. 2 shows a schematic perspective view of a light guide block 10A having a light extraction layer 20. The light guide block 10A having a light extraction layer 20 is sometimes referred to as a light guide member 10M1.

As shown in FIG. 1, the optical member 100A illustrated here has one light guide block row 10R1 in which three light guide blocks 10A are arranged along the light guide direction (z direction). As shown by the white arrow in FIG. 1, light emitted from below toward the light guide block row 10R1 is diffused by the light diffusion structure of the light guide block 10A and propagates in the z direction within the light guide block row 10R1. Of the light propagating within the light guide block row 10R1, a portion of the light that enters the light extraction layer 20 is emitted to the outside as shown by the black arrow. The optical member 100A has one light guide block 10A that does not have a light extraction layer, and two light guide members 10M1 that have a light extraction layer 20 only on one side of the light guide block 10A. Of course, the light guide block 10A in which the light extraction layer 20 is arranged can be changed arbitrarily, and the number of light extraction layers 20 can also be changed arbitrarily.

As shown in FIG. 2, the light guide block 10A has a light receiving surface RS, an exit surface OS opposite the light receiving surface RS, and four side surfaces SSa, SSb, SSc, and SSd between the light receiving surface RS and the exit surface OS. Here, light is emitted from the bottom of the drawing toward the light receiving surface RS (in the z direction), so the light receiving surface RS is located on the bottom and the exit surface OS is located on the top.

A light diffusion structure DS is formed on the light receiving surface RS of the light guide block 10A. The light diffusion structure DS broadly includes structures that diffuse (opposite to converging) light, and includes, for example, a diffusion lens array, a diffusion prism array, and a scattering structure (rough surface). The light diffusion structure DS is preferably an uneven structure formed on the light receiving surface RS. The uneven structure may be formed by processing the flat surface of the block, or a film having an uneven structure may be attached to the flat surface of the block. In this case, it is preferable that the refractive indexes of the film, adhesive, and block are matched so that no optical interface is formed between the film, adhesive, and block, and the refractive index difference is preferably 0.1 or less. Note that the uneven structure constituting the light diffusion structure DS is small (for example, the height difference and pitch (average value of adjacent distances when there is no regularity) are about 1 μm or more and about 200 μm or less), so that the light guide block 10A including the light diffusion structure DS can be said to be approximately a rectangular parallelepiped (here, approximately a cube). Furthermore, the light diffusion structure DS is not limited to a concave-convex structure, but may be a light diffusion layer in which fine particles having a refractive index different from that of the resin matrix are dispersed in the resin matrix (see FIG. 10). The refractive index of the resin matrix (and the adhesive used if necessary) preferably matches the refractive index of the block, and the difference in refractive index is preferably 0.1 or less.

Light guide block 10B, which will be described later with reference to Figure 6, has a light diffusion structure DS on the exit surface OS. Light guide block 10B can be obtained by turning light guide block 10A upside down (opposite the light guiding direction), but for example, the structures of the diffusion lens array and diffusion prism array may be different when formed on the light receiving surface RS and when formed on the exit surface OS. Also, the scattering structure (rough surface) may be the same when formed on the light receiving surface RS and when formed on the exit surface OS.

The light-guiding block 10A has four side surfaces SSa, SSb, SSc, and SSd, of which the light-extraction layer 20 is disposed only on side surface SSb. The light-extraction layer 20 may be disposed on two or more surfaces. The light-extraction layer 20 may be a layer having a known light-extraction structure, but it is preferable to use a light-extraction layer having multiple internal spaces that extract light by total internal reflection, as described below with reference to FIG. 4.

The light guide block row 10R1 shown in FIG. 1 has three light guide blocks 10A arranged in the z direction. For example, when the z direction is the opposite vertical direction, the two upper light guide blocks 10A are stacked so that the light receiving surface RS faces the light emitting surface OS of the light guide block 10A below. That is, the upper light guide block 10A is placed on the light emitting surface OS of the lower light guide block 10A by gravity. When the light diffusion structure DS of the light receiving surface RS has an uneven structure, even if the light receiving surface RS of the upper light guide block 10A is brought into contact with the light emitting surface OS (flat surface: having enough flatness to prevent light scattering) of the lower light guide block 10A, air will be interposed between the flat surface of the light emitting surface OS and the uneven structure of the light diffusion structure DS of the light receiving surface RS. By interposing air, the diffusion lens array and the diffusion prism array diffuse light by refraction. Although the light exit surface OS and the light receiving surface RS do not necessarily need to be in contact with each other, it is preferable to place them as close as possible to each other so that light does not leak out of the light guide block row 10R1 from between the light exit surface OS and the light receiving surface RS. An adhesive layer (including a pressure-sensitive adhesive layer) that does not fill the surface irregularities may be provided on the light diffusion structure DS of the light exit surface OS and/or the light receiving surface RS to bond two adjacent light guide blocks 10A together. If the pressure-sensitive adhesive layer is used, the user can easily peel off (separate) the two light guide blocks 10A. The light guide block row 10R1 may also be fixed using a separately provided support. If the light guide block row 10R1 is fixed using an adhesive layer and/or a support, the light guide block row 10R1 can also be arranged in a direction that crosses the vertical direction, for example, in the horizontal direction.

The adhesive layer is preferably, for example, (meth)acrylic or polyester-based, and has a storage modulus G' of 1.2 x ¹⁰⁵ Pa or more at 25°C. There is no particular upper limit to the storage modulus G' at 25°C, but it is, for example, 1.0 x ^107. If the storage modulus G' at 25°C is less than 1.2 x ¹⁰⁵ Pa, the unevenness of the surface of the light diffusion structure is easily filled, and the amount of light that can be extracted from the light extraction layer is reduced.

Figure 3 shows a schematic partial cross section of a portion of the light-guiding block 10A that includes the light-receiving surface RS. The light-diffusing structure DS of the light-receiving surface RS is an uneven structure, a fine uneven structure formed by roughening the light-receiving surface RS, and scatters light. The average roughness Ra of such a fine uneven structure is, for example, 1.6 μm or more and 100 μm or less.

The light guide block 10A is made of a colorless, transparent material that has a high transmittance of visible light (light with a wavelength of 380 nm or more and 780 nm or less). For example, the material that makes up the light guide block 10A preferably has a visible light transmittance of 70% or more, and a haze value of 5% or less. The visible light transmittance and haze value can be measured, for example, using a haze meter (manufactured by Murakami Color Research Laboratory: product name HM-150).

Such colorless and transparent materials include acrylic resin (e.g. PMMA), optical plastics such as polycarbonate, and optical glass. The surface of optical plastic can be roughened using sandpaper, for example. The surface of optical glass can be roughened using a grindstone, for example. The degree of fine irregularities in the roughened surface (surface roughness) can be evaluated, for example, by the average roughness Ra measured using a laser microscope (VK-X1000 manufactured by KEYENCE). The average roughness Ra is, for example, 1.6 μm or more and 100 μm or less, and more preferably 1.7 μm or more and 80 μm or less. If the average roughness Ra is less than 1.6 μm, the amount of diffused (scattered) light is reduced, and the amount of light that can be extracted by the light extraction layer 20 is reduced. On the other hand, even if the average roughness Ra exceeds 100 μm, the amount of diffused (scattered) light does not increase, and the time required for roughening becomes unnecessarily long.

FIG. 4 shows a schematic partial cross-sectional view of a portion of the light guide member 10M1 including the light extraction layer 20. The light extraction layer 20 has a plurality of internal spaces 24 in the transparent member 22 that extract light by total internal reflection (TIR). Light extraction structures having internal spaces (air cavities) are described, for example, in WO 2019/182091, WO 2019/146628, WO 2011/124765, and WO 2019/087118. The disclosures of these four international publications are all incorporated herein by reference. Specific examples of the light extraction layer 20 will be described later with reference to FIG. 9, etc.

FIG. 5 shows a schematic perspective view of an optical element 100B according to another embodiment of the present invention. As with the optical element 100A shown in FIG. 1, the optical element 100B has one light guide block row 10R1 in which three light guide blocks 10A are arranged along the light guide direction (z direction). The optical element 100B differs from the optical element 100A in that the side of the central light guide block 10A on which the light extraction layer 20 is arranged is different from that of the optical element 100A. In this way, it is possible to provide different illumination by simply changing the position of the side on which the light extraction layer 20 is arranged. Of course, the light guide block 10A on which the light extraction layer 20 is arranged can be changed as desired, and the number of light extraction layers 20 can also be changed as desired.

FIG. 6 shows a schematic perspective view of an optical element 100C according to yet another embodiment of the present invention. The optical element 100C has one light guide block row 10R2 in which three light guide blocks 10B, 10B, and 10C are arranged along the light guide direction (z direction). The light guide block 10B differs from the light guide block 10A shown in FIG. 1 in that it has a light diffusion structure DS on the exit surface OS. The top light guide block 10C has no light diffusion structure on either the light receiving surface RS or the exit surface OS. The optical element 100B has one light guide block 10B without a light extraction layer, one light guide member 10M2 having a light extraction layer 20 only on one side of the light guide block 10B, and one light guide member 10M3 having a light extraction layer 20 only on one side of the light guide block 10C. Of course, the light guide block 10B on which the light extraction layer 20 is arranged can be changed as desired, and the number of light extraction layers 20 can also be changed as desired.

Figure 7 shows a schematic perspective view of an optical element 100D according to yet another embodiment of the present invention. The optical element 100D has one light guide block row 10R3 in which three light guide blocks 10C, 10A, 10A are arranged along the light guide direction (z direction). The bottom light guide block 10C has no light diffusion structure on either the light receiving surface RS or the light exiting surface OS. In this way, a block row combining light guide blocks 10C that do not have a light diffusion structure can also be used. A light guide block having a light diffusion structure DS on both the light receiving surface RS and the light exiting surface OS can also be used.

Next, FIG. 8 shows a schematic perspective view of an optical device 1000 according to an embodiment of the present invention. The optical member 100E of the optical device 1000 has six light guide block rows 110R1, 110R2, 110R3, 110R4, 110R5, and 110R6 arranged in parallel. A gap (air layer) is provided between adjacent light guide block rows. Each block row has six light guide blocks 10A. Therefore, the optical member 100E has 6 x 6 = 36 light guide blocks 10A. Of the 36 light guide blocks 10A, light extraction layers 20 are arranged on the side faces of 16 light guide blocks 10A facing the same direction. The 16 light extraction layers 20 are arranged to form the letter N.

The optical device 1000 has a light source 30 arranged to emit light toward the six light guide block rows 110R1, 110R2, 110R3, 110R4, 110R5, and 110R6. Here, an example is shown in which one light source 30 is provided for each light guide block row, but light may be emitted from one light source to the six light guide block rows 110R1, 110R2, 110R3, 110R4, 110R5, and 110R6. By providing one light source 30 for each light guide block row, for example, it is possible to display different colors for each light guide block row.

The optical device 1000 can display the letter N by turning on the light source 30. In other words, by using an optical member having a row of multiple light guide blocks arranged in parallel and changing the arrangement of the light guide blocks on which the light extraction layer 20 is arranged, an optical device can be obtained that can display various characters, pictures, and the like in dots.

Next, a preferred example of the light extraction layer 20A will be described with reference to Figures 9, 10, 11A, and 11B.

FIG. 9 is a schematic cross-sectional view of a light extraction film 200 used in the manufacture of an optical component according to an embodiment of the present invention. The light extraction film 200 has a shaping film 22 having a recess 24 (indicated by the same reference number as the internal space) on its surface, an adhesive layer 26, a base layer 42, a pressure-sensitive adhesive layer 28, and a release sheet 44.

By providing an adhesive layer 26 so as to cover the recesses 24 on the surface of the shaping film 22, a light extraction layer 20A having an internal space 24 is obtained. The adhesive layer 26 is adhered to the shaping film 22 while being supported by the base layer 42. The release sheet 44 is peeled off, and the exposed adhesive layer 28 is adhered to the side of the light guide block.

The orientation distribution of the light emitted from the light extraction layer 20A can be controlled, for example, by adjusting the cross-sectional shape, planar shape, size, arrangement density, and distribution of the internal space 24. As described later with reference to FIG. 11A, the inclination angle θa of the front inclined surface ISa is, for example, 10° or more and 70° or less. Also, the inclination angle θb of the rear inclined surface ISb is, for example, 50° or more and 100° or less. The cross-sectional shape of the internal space 24 is triangular as exemplified here, but is not limited to this and may be trapezoidal or the like independently.

When viewed from the normal direction of the main surface of the light extraction layer 20A, the ratio of the area of the multiple internal spaces 24 to the area of the light extraction layer 20A (occupancy rate) is preferably 1% or more and 80% or less, with the upper limit being more preferably 50% or less, and even more preferably 45% or less, and in order to obtain a high transmittance and/or a low haze value, it is preferably 30% or less, more preferably 10% or less, and even more preferably 5% or less. For example, when the occupancy rate of the internal spaces is 50%, a haze value of 30% can be obtained. The occupancy rate of the internal spaces 24 is, for example, uniform.

An example of the planar shape and arrangement of the internal space 24 will be described with reference to FIG. 10. FIG. 10 shows a schematic plan view of the light extraction film 200. The shape of the internal space 24 will be described with reference to FIG. 11A and FIG. 11B. FIG. 11A is a schematic cross-sectional view of the internal space 24, and FIG. 11B is a schematic plan view of the internal space 24.

As shown in FIG. 10, the multiple internal spaces 24 are discretely arranged, for example, in the light guiding direction (z direction) of the light guiding block and in a direction perpendicular to the light guiding direction (x direction). The size of the internal spaces 24 (length L, width W: see FIG. 11A and FIG. 11B) is, for example, preferably such that the length L is 10 μm or more and 500 μm or less, and the width W is 1 μm or more and 100 μm or less. From the viewpoint of light extraction efficiency, the height H (see FIG. 11A) is preferably 1 μm or more and 100 μm or less.

In this example, multiple internal spaces 24 are discretely arranged in the light guide direction (z direction) and in a direction perpendicular to the light guide direction (x direction), but this is not limiting.

The multiple internal spaces 24 are arranged discretely, for example, in the light guide direction and in a direction intersecting the light guide direction. The discrete arrangement may or may not have periodicity (regularity) in at least one direction. However, from the viewpoint of mass production, it is preferable that the multiple internal spaces 24 are arranged uniformly. For example, in the example shown in FIG. 10, multiple internal spaces 24 having substantially the same shape and a curved surface convex in the same direction are arranged discretely and periodically in the entire region of the light extraction layer 20A in the light guide direction (z direction) and the direction perpendicular to the light guide direction (x direction). In this case, the pitch Px is preferably, for example, 10 μm or more and 500 μm or less, and the pitch Pz is preferably, for example, 10 μm or more and 500 μm or less. In the example shown in FIG. 10, there are further internal spaces arranged at a half pitch in each of the z direction and the x direction.

As shown in FIG. 10, when viewed from the normal direction to the main surface of the light extraction layer 20A, the forward inclined surface ISa forms a curved surface that is convex toward the light source LS. Instead of the discrete internal spaces 24, for example, an internal space such as a groove (e.g., a triangular prism) extending in the x direction may also be used.

11A, the cross-sectional shape of the internal space 24 is, for example, a triangle. The inclination angle θa of the front inclined surface ISa on the light source LS side is, for example, 10° or more and 70° or less. If the inclination angle θa is smaller than 10°, the controllability of the light distribution may decrease, and the light extraction efficiency may also decrease. On the other hand, if the inclination angle θa exceeds 70°, for example, manufacturing may become difficult. In addition, the inclination angle θb of the rear inclined surface ISb is, for example, 50° or more and 100° or less. If the inclination angle θb is smaller than 50°, stray light may occur in an unintended direction. On the other hand, if the inclination angle θb exceeds 100°, for example, manufacturing may become difficult. As shown in FIG. 11B, the length L of the internal space 24 is preferably 10 μm or more and 500 μm or less, and the width W is preferably 1 μm or more and 100 μm or less. The length L is, for example, at least twice the width W. The height H (see FIG. 11A) is preferably 1 μm or more and 100 μm or less.

Preferred examples of each component of a lighting device according to an embodiment of the present invention are described below.

The shaped film for forming the internal space can be manufactured, for example, as follows. A textured shaped film was manufactured according to the method described in JP-A 2013-524288. Specifically, the surface of a polymethylmethacrylate (PMMA) film was coated with lacquer (Finecure RM-64, manufactured by Sanyo Chemical Industries), an optical pattern was embossed on the film surface containing the lacquer, and the lacquer was then cured to manufacture the desired textured shaped film. The total thickness of the textured shaped film was 130 μm.

The thickness of the substrate layer is, for example, 1 μm or more and 1000 μm or less, preferably 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less. The refractive index of each substrate layer is preferably, independently, 1.40 or more and 1.70 or less, and more preferably 1.43 or more and 1.65 or less.

The thickness of each adhesive layer is, for example, independently 0.1 μm or more and 100 μm or less, preferably 0.3 μm or more and 100 μm or less, and more preferably 0.5 μm or more and 50 μm or less. The refractive index of each adhesive layer is, independently, preferably 1.42 or more and 1.60 or less, and more preferably 1.47 or more and 1.58 or less. In addition, the refractive index of the adhesive layer is preferably close to the refractive index of the light-guiding layer, shaping film, or base layer to which it is in contact, and the absolute value of the difference in refractive index is preferably 0.2 or less.

The adhesive layer that contacts the recesses on the surface of the shaped film and forms the internal space can preferably be bonded without filling the recesses on the surface of the shaped film. As an adhesive suitable for forming such an adhesive layer, the adhesives described in WO 2021/167090, WO 2021/167091 or WO 2022/176658 by the present applicant can be preferably used. All of the disclosures of these applications are incorporated herein by reference. In particular, the polyester-based adhesives described in WO 2022/176658 are preferred.

Furthermore, a low refractive index layer, a hard coat layer, an anti-reflection layer, an anti-fouling layer, etc. may be provided on, for example, the front surface of the optical component. These may be formed using known materials.

The refractive index n of the low refractive index layer is preferably, for example, 1.30 or less, more preferably 1.20 or less, and even more preferably 1.15 or less. The low refractive index layer is preferably a solid, and the refractive index is, for example, 1.05 or more. The difference between the refractive index of the light guiding block and the refractive index of the low refractive index layer is preferably 0.20 or more, more preferably 0.23 or more, and even more preferably 0.25 or more. The low refractive index layer with a refractive index of 1.30 or less may be formed, for example, using a porous material. The thickness of the low refractive index layer is, for example, 0.3 μm or more and 5 μm or less.

When the low refractive index layer is a porous material having internal voids, the porosity is preferably 35 volume % or more, more preferably 38 volume % or more, and particularly preferably 40 volume % or more. Within this range, a low refractive index layer with a particularly low refractive index can be formed. The upper limit of the porosity of the low refractive index layer is, for example, 90 volume % or less, and preferably 75 volume % or less. Within this range, a low refractive index layer with excellent strength can be formed. The porosity is a value calculated from the refractive index measured with an ellipsometer using Lorentz-Lorenz's formula.

The low refractive index layer having voids includes silica particles, silica particles having micropores, approximately spherical particles such as hollow silica nanoparticles, fibrous particles such as cellulose nanofibers, alumina nanofibers, and silica nanofibers, and flat particles such as nanoclay composed of bentonite. In one embodiment, the low refractive index layer having voids is a porous body formed by direct chemical bonding of particles (e.g., microporous particles). In addition, at least a portion of the particles constituting the low refractive index layer having voids may be bonded to each other via a small amount (e.g., equal to or less than the mass of the particles) of a single binder component. The porosity and refractive index of the low refractive index layer can be adjusted by the particle size, particle size distribution, etc. of the particles constituting the low refractive index layer.

Methods for obtaining a low refractive index layer having voids include, for example, the methods described in JP 2010-189212 A, JP 2008-040171 A, JP 2006-011175 A, WO 2004/113966 A, and references thereto. The disclosures of JP 2010-189212 A, JP 2008-040171 A, JP 2006-011175 A, and WO 2004/113966 A are all incorporated herein by reference.

A porous silica body can be suitably used as a low refractive index layer having voids. The porous silica body is manufactured, for example, by the following method. Silicon compounds; a method of hydrolyzing and polycondensing at least one of hydrolyzable silanes and/or silsesquioxanes, and their partial hydrolyzates and dehydration condensates, a method of using porous particles and/or hollow fine particles, a method of generating an aerogel layer by utilizing the springback phenomenon, a method of using a crushed gel in which a gel-like silicon compound obtained by a sol-gel method is crushed and the resulting crushed body, that is, microporous particles, are chemically bonded to each other with a catalyst or the like, and the like. However, the low refractive index layer is not limited to a porous silica body, and the manufacturing method is not limited to the exemplified manufacturing method, and may be manufactured by any manufacturing method. However, the porous layer is not limited to a porous silica body, and the manufacturing method is not limited to the exemplified manufacturing method, and may be manufactured by any manufacturing method. Silsesquioxane is a silicon compound having ( _RSiO1.5 , R is a hydrocarbon group) as a basic structural unit, and is strictly different from silica having _SiO2 as a basic structural unit. However, it is common to silica in that it has a network structure cross-linked by siloxane bonds. Therefore, in this specification, a porous material containing silsesquioxane as a basic structural unit is also referred to as a silica porous material or a silica-based porous material.

The porous silica body may be composed of microporous particles of a gel-like silicon compound bonded together. Examples of the microporous particles of the gel-like silicon compound include pulverized bodies of the gel-like silicon compound. The porous silica body may be formed, for example, by applying a coating liquid containing the pulverized bodies of the gel-like silicon compound to a substrate. The pulverized bodies of the gel-like silicon compound may be chemically bonded (e.g., siloxane bonds) by, for example, the action of a catalyst, exposure to light, heating, etc.

FIG. 12 shows a schematic perspective view of a light-guiding member 10M2 according to an embodiment of the present invention.

The light guide member 10M2 has a light guide block 10C having a light receiving surface RS, an exit surface OS opposite to the light receiving surface RS, and four side surfaces between the light receiving surface RS and the exit surface OS. The light guide block 10C does not have a light diffusion structure. The light guide member 10M2 has a light extraction layer 20 arranged on one side. Instead of a light diffusion structure, the light guide member 10M2 has an adhesive layer 18 having light diffusion properties arranged on the light receiving surface RS. The adhesive layer 18 is an adhesive layer 18 having light diffusion properties in which fine particles having a refractive index different from that of the adhesive matrix are dispersed in an adhesive matrix. The adhesive layer 18 may be provided on the exit surface OS. Even when this light guide member 10M2 is used, an optical member similar to the above embodiment can be obtained.

Figures 13A to 13D show optical images of the prototype optical components.

The optical component shown in Figure 13A was obtained by stacking two light-guiding blocks. Figure 13A is an optical image of the optical component irradiated from below with light from an LED (Asic Al-1030).

The lower light guide block (referred to as BLa) has a roughly rectangular parallelepiped shape and is formed using an acrylic plate with dimensions of 100 mm width x 20 mm depth x 40 mm height. A fine uneven structure was formed by roughening the top surface (light output surface) of the acrylic plate. The average roughness Ra of the fine uneven structure was 2.0 μm. No light extraction layer was provided on the four side surfaces. Therefore, the lower light guide block is dark in Figure 13A.

The second upper light guide block (referred to as BLb) was a light guide block formed in the same manner as the lower light guide block. The average roughness Ra of the fine uneven structure on the upper surface (exit surface) was 2.0 μm. A light extraction layer was provided on one of the four side surfaces (the front surface in the figure). The parameters characterizing the light extraction layer (see Figures 10, 11A, and 11B) are shown below.
Thickness: 100μm
Recess: L = 80 μm, W = 20 μm, H = 10 μm
First inclined surface: curved surface (fourth order curve), inclination angle θa = 30°
Second inclined surface: flat surface (straight line), inclination angle θb = 70°
Pitch Px = 200 μm, pitch Pz = 100 μm, occupied area ratio 5%

In addition, a low refractive index layer was formed on the surface of the light extraction layer, and a hard coat layer was formed on the low refractive index layer. The low refractive index layer was formed using the above-mentioned porous silica body, had a refractive index of 1.20, and was approximately 0.9 μm thick. The hard coat layer (surface hardness: 2H-3H) was formed using a hollow silica layer on the outermost surface and an organic conductive hard coat layer underneath. The thickness of the hollow silica layer was approximately 80-100 nm, and the thickness of the organic conductive hard coat layer was approximately 10 μm.

The optical member shown in FIG. 13B was obtained by stacking a light guiding block (third light guiding block) having the same configuration as the light guiding block BLb on top of the optical member shown in FIG. 13A. The optical member shown in FIG. 13C was obtained by stacking a light guiding block (fourth light guiding block) having the same configuration as the light guiding block BLb on top of the optical member shown in FIG. 13B. In the optical member shown in FIG. 13D, the first, third, and fifth light guiding blocks from the bottom are light guiding blocks having the same configuration as the light guiding block BLa, and the second, fourth, and sixth light guiding blocks are light guiding blocks having the same configuration as the light guiding block BLb.

In this way, it can be seen that light can be extracted efficiently from a light guide block provided with a light extraction layer. A variety of illumination and display can be achieved by using a light guide block row that combines various light guide blocks. Furthermore, users can easily change the number of light guide blocks, the type of light guide block, the arrangement of the light guide block row, and the combinations of these.

The optical device, light-guiding block and optical member according to the embodiments of the present invention can provide a completely new form of use, allowing the user to easily change the size.

10A: Light guide block, 10R1: Light guide block row, 20: Light extraction layer, 100A: Optical member

Claims

at least one light guide block row in which a plurality of light guide blocks are arranged along a light guide direction, each of the plurality of light guide blocks having a light receiving surface, an emission surface opposite to the light receiving surface, and at least three side surfaces between the light receiving surface and the emission surface, the at least one light guide block row including a first light guide block having a light diffusion structure formed on the light receiving surface or a second light guide block having a light diffusion structure formed on the emission surface;
a light extraction layer disposed on at least one of the at least three side surfaces of the first light guide block, or a light extraction layer disposed on at least one of the at least three side surfaces of a light guide block disposed on the exit surface side of the second light guide block.
The optical element according to claim 1, wherein the light diffusion structure is a concave-convex structure formed on the light receiving surface or the light emitting surface.
The optical element according to claim 2, wherein the uneven structure is a fine uneven structure formed by roughening the light receiving surface or the light emitting surface.
The optical member according to claim 3, wherein the average roughness Ra of the fine uneven structure is 1.6 μm or more and 100 μm or less.
The optical member according to claim 1, wherein the plurality of light guide blocks in the at least one light guide block row includes a light guide block that does not have a light extraction layer on the at least three side surfaces.
The optical element according to claim 1, wherein the light extraction layer has a plurality of internal spaces that extract light by total internal reflection.
The optical member according to claim 1, wherein the light guide block has a substantially rectangular parallelepiped shape.
The optical member according to any one of claims 1 to 7, wherein the at least one light guide block row includes a plurality of light guide block rows arranged in parallel.
The optical member according to any one of claims 1 to 8, wherein the at least one light guide block row further includes an adhesive layer disposed on the light diffusion structure.
The optical member according to claim 1 ;
a light source arranged to emit light toward the plurality of light guide block rows.
a light guiding block having a light receiving surface, an emission surface opposite the light receiving surface, and at least three side surfaces between the light receiving surface and the emission surface;
a light extraction layer disposed on at least one of the at least three sides;
a light-diffusing adhesive layer disposed on at least one of the light-receiving surface and the light-emitting surface.