JP3071247B2 - Light guide plate for surface light emitting device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate for a surface light emitting device capable of obtaining high luminance surface light emission and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in a light guide plate for a surface light emitting device, a light diffusion layer 3 is formed on the back surface of a transparent light guide 1 having a flat surface by a printing method or a transfer method (FIG. 9 and FIG. 9). 10). The light diffusion layer 3 is formed in a gradation pattern, and a part of the light emitted from the line light source is scattered and reflected in a small area in the vicinity of the line light source to guide the light to the upper surface of the transparent light guide 1 and to a part far from the line light source. Has scattered and reflected most of the light that has been totally reflected inside the transparent light guide 1 within a large area and guided the light to the surface of the transparent light guide 1.

[0003]

However, in a conventional surface light emitting device using a light guide plate for a surface light emitting device, since the front and back surfaces of the light diffusion layer are flat, the entire surface of the light diffusion layer faces the transparent light guide. There was a loss in the scattered reflection due to the reflected light and the light transmitted through the inside of the light diffusion layer, and sufficient luminance was not obtained. Therefore, an object of the present invention is to provide a light-emitting plate for a surface-emitting device in which light is more efficiently scattered and reflected on the upper surface of a transparent light-guide by a light-diffusing layer to obtain high-luminance surface light, and a method for manufacturing the same. is there.

[0004]

In order to achieve the above object, the present invention provides a light diffusing layer having at least one of its front and back surfaces having irregularities, thereby scattering and reflecting more light rays, thereby achieving high brightness. This was configured to obtain surface light emission.

Namely, the surface-emitting device for the light guide plate of the present invention, the light diffusing layer through the adhesive layer to the transparent light guiding body backside Glade
The light diffusion layer was transferred so as to have irregularities on the interface between the light diffusion layer and the adhesive layer and on the back surface of the light diffusion layer. The method for manufacturing a light guide plate for a surface light emitting device having the above-described configuration includes coating or printing a radiation-curable resin containing a light-diffusing pigment on a base sheet having an uneven surface, and crosslinking the radiation-curable resin by irradiation with radiation. A light diffusion layer having irregularities on the surface was formed by shrinking, a transfer material having an adhesive layer formed on the light diffusion layer was transferred to the rear surface of the transparent light guide, and then the base sheet was peeled off.

In the light guide plate for a surface light emitting device according to the present invention, the light diffusion layer is provided with a gradation on the back surface of the transparent light guide via an adhesive layer.
The pattern was transferred so as to have irregularities only at the interface between the light diffusion layer and the adhesive layer. The method for manufacturing a light-emitting plate for a surface-emitting device having the above-described structure includes coating or printing a radiation-curable resin containing a light-diffusing pigment on a flat base sheet, and crosslinking and shrinking the radiation-curable resin by irradiation with radiation. A light diffusion layer having irregularities on the surface was formed by using a transfer material having an adhesive layer formed on the light diffusion layer, the image was transferred to the rear surface of the transparent light guide, and then the base sheet was peeled off.

In the light guide plate for a surface light emitting device according to the present invention, the light diffusion layer is formed on the back surface of the transparent light guide in a gradation pattern.
Is copy was configured to have an uneven only on the back surface of the light-diffusing layer. The method for manufacturing a light guide plate for a surface light emitting device having the above configuration uses a transfer material having a light diffusion layer formed by applying or printing a resin containing a light diffusible pigment on a base sheet having an uneven surface. It was configured to transfer to the back surface of the light guide, and then peel off the base sheet.

In the light guide plate for a surface light emitting device according to the present invention, the light diffusion layer is provided with a gradation on the back surface of the transparent light guide via an adhesive layer.
The light diffusion layer was transferred in a pattern, and only the back surface of the light diffusion layer had irregularities. The method for manufacturing a light-emitting plate for a surface-emitting device having the above configuration includes forming a light-diffusing layer by applying or printing a resin containing a light-diffusing pigment on a base sheet having an uneven surface. Using a transfer material having an adhesive layer formed thereon, transfer was performed on the rear surface of the transparent light guide, and then the base sheet was peeled off.

Hereinafter, a more detailed description will be given with reference to the drawings. FIG. 1 is a partially enlarged sectional view showing one embodiment of the light guide plate for a surface light emitting device of the present invention, and FIGS. 2 to 4 are partially enlarged sectional views showing another embodiment of the light guide plate for a surface light emitting device of the present invention. Figure 5
FIG. 8 is a partially enlarged sectional view showing one embodiment of the method for manufacturing the light guide plate for the surface light emitting device of FIGS. Reference numeral 1 denotes a transparent light guide, 2 denotes a light diffusion portion, 3 denotes a light diffusion layer, and 4 denotes an adhesive layer.

First, a light guide plate for a surface light emitting device according to the present invention will be described. The transparent light guide 1 is preferably a transparent rectangular plate made of transparent plastic and having a thickness of about 1 to 30 mm. As a material of the transparent light guide 1, an acrylic resin, glass, polycarbonate, polyvinyl chloride, or the like may be used.

On the back surface of the transparent light guide 1, the light diffusing layer 3 is interposed via the adhesive layer 4 in a gradation pattern having a small area ratio near the line light source and a large area ratio near the line light source. It is formed. If the light guide side surface of the light diffusion layer 3 is flat and has an adhesive property,
The adhesive layer 4 may be omitted. The gradation pattern of the light diffusion layer 3 has a dot shape, a stripe shape, a square shape, a chain shape, and the like. The light diffusion layer 3 is a resin layer containing a light diffusion pigment, and has irregularities on the interface between the adhesive layer 4 and the light diffusion layer 3 and / or on the back surface of the light diffusion layer 3. As the adhesive layer 4, a transparent resin generally used as an adhesive layer for a transfer material is used, and an acrylic resin is particularly preferably used. As the light diffusing pigment, it is preferable to use a transparent pigment such as calcium carbonate or silica having a refractive index substantially equal to or less than the refractive index of the light guide.

The light-diffusing pigment has a function of scattering and reflecting light rays, and has an adhesive layer 4 and a light-diffusing layer 3 which will be described later.
Also has the function of forming irregularities at the interface between them. The unevenness of the light diffusing pigment can be increased by increasing the mixing amount. Further, when the resin of the light diffusion layer 3 has unevenness at the interface between the adhesive layer 4 and the light diffusion layer 3, the radiation curable resin is used by being cross-linked and contracted by irradiation with radiation. Examples of the radiation curable resin include an electron beam curable resin and an ultraviolet curable resin. As the electron beam-curable resin, a resin obtained by mixing a photopolymerizable monomer such as pentaerythritol acrylate / trimethylolpropane triacrylate with polyester acrylate / polyester urethane acrylate / epoxy acrylate / polyol acrylate is used. In addition, as an ultraviolet curable resin, polyester acrylate, polyester urethane acrylate, epoxy acrylate, polyol acrylate, etc., as a photoinitiator, acetone phenone type, benzoin ether type, benzyl ketal type, etc.
A mixture containing a ketone-based initiator, a reactive diluent composed of mono-, di-, or trivinyl compounds such as hydroxyethyl acrylate / diethylene glycol dimethacrylate is used. Further, as the radiation-curable resin used here, when it is desired to increase the unevenness of the interface between the adhesive layer 4 and the light diffusion layer 3, it is preferable to select a resin having a high shrinkage rate upon irradiation with radiation.

In order to obtain the light guide plate for a surface light emitting device as described above, a transfer sheet as described below is used and the base sheet 2 is used.
The transfer material is transferred on the back surface of the transparent light guide plate by superimposing and adhering the transfer material with the light diffusion layer 3 side down, and then the base sheet 2 is peeled off.

As the base sheet 2, a plastic film such as polyethylene terephthalate / polypropylene / polyethylene / nylon / cellophane or a composite film of these and paper, which is used as the base sheet 2 of a normal transfer material, is used.

When forming irregularities on the back surface of the light diffusion layer 3 provided on the back surface of the transparent light guide 1, a base sheet 2 having an uneven surface is used. As the base sheet 2 having an uneven surface, a base sheet 2 having a surface provided with unevenness by a physical means such as a sand blast method, a chemical etching method, or a sand paper polishing method, an extender pigment or wax on the base sheet 2 It is preferable to use a material in which a layer having an additive such as is formed. Furthermore, if necessary, a release layer may be formed on the base sheet 2 or a release layer that is peeled off together with the base sheet 2 such as a hot-melt wax, a silicone resin, or a curable melamine resin. When the surface of the base sheet 2 is smooth, a release layer may be provided thereon.

On the base sheet 2, the light diffusion layer 3 and the adhesive layer 4 having the above-mentioned components are formed so that the light diffusion layer 3 becomes a gradation pattern after the transfer. When the surface of the light diffusion layer 3 is flat and has adhesiveness, the adhesive layer 4 may be omitted.

The light diffusing layer 3 and the adhesive layer 4 are formed by a printing method such as a screen printing method or a gravure printing method, a gravure coater method, or a reverse coater method. When a radiation-curable resin is used as the resin of the light diffusion layer 3, irradiation is performed after the formation of the light diffusion layer 3. Irregularities can be formed on the surface of the light-diffusing layer 3 by the crosslinking shrinkage of the radiation-curable resin due to the radiation irradiation and the light-diffusing pigment present in the radiation-curable resin.

[0018]

When a line light source is disposed on the side surface of the light guide plate for a surface light emitting device having the above-described structure, light rays emitted from the line light source have the same incident angle and the same reflection angle inside the light guide 1 and repeat total reflection.
The light beam is scattered and reflected by the light diffusion portion and is guided to the upper surface side. According to the configuration of the present invention, the adhesive layer 4 of the light diffusion layer 3 and the light diffusion layer 3
And / or unevenness on the back surface of the light diffusion layer 3 can more efficiently scatter and reflect light rays toward the surface light emitting surface of the light guide plate.

[0019]

【Example】

Example 1 A polyethylene terephthalate film whose surface was sandblasted was used as a base sheet 2, and a radiation curable resin composed of polyester acrylate and pentaerythritol acrylate containing calcium carbonate as a light diffusing pigment was entirely coated thereon with a gravure coater. The radiation-curable resin was cross-linked and shrunk by electron beam irradiation to form a light diffusion layer 3 having irregularities on the surface, and an adhesive layer 4 was formed on the light diffusion layer 3 in a gradation pattern by screen printing. Using a transfer material, the light was transferred onto the back surface of the transparent light guide 1 made of an acrylic resin plate, and then the base sheet 2 was peeled off to produce a light guide plate for a surface emitting device (see FIGS. 1 and 5). When a line light source is disposed on the side surface of the light guide plate for a surface light emitting device obtained in this manner, the light beam is generated due to the interface between the adhesive layer 4 of the light diffusion layer 3 and the light diffusion layer 3 and the unevenness on the back surface of the light diffusion layer 3. Can be more efficiently scattered and reflected on the surface light-emitting surface side of the light guide plate, and high-luminance surface light was obtained.

Example 2 A polyethylene film was used as the base sheet 2, and a radiation curable resin containing silica as a light diffusing pigment and containing polyol acrylate, ketone initiator and hydroxyethyl acrylate was screen-printed on a gradation pattern. Then, the radiation-curable resin is cross-linked and contracted by ultraviolet irradiation to form the light diffusion layer 3 having irregularities on the surface, and the adhesive layer 4 is entirely formed on the light diffusion layer 3 using a transfer material formed by a reverse coater method. Then, the light was transferred onto the back surface of the transparent light guide 1 made of a glass plate, and then the base sheet 2 was peeled off to produce a light guide plate for a surface emitting device (see FIGS. 2 and 6). When a line light source is arranged on the side surface of the light guide plate for a surface light emitting device obtained in this way, the light guide plate is more efficiently transmitted by the unevenness of the interface between the adhesive layer 4 of the light diffusion layer 3 and the light diffusion layer 3. The surface light-emitting surface side could be scattered and reflected, and high-luminance surface light was obtained.

Example 3 A polyethylene film having a surface chemically etched is used as a base sheet 2, and a light diffusion layer 3 made of an acrylic resin containing silica as a light diffusion pigment and having adhesive properties is formed on the base sheet 2 in a gradation pattern. Using a gravure-printed transfer material, the transfer material was transferred onto the back surface of the transparent light guide 1 made of a glass plate, and then the base sheet 2 was peeled off to produce a light guide plate for a surface emitting device (see FIGS. 3 and 7). When a line light source is arranged on the side surface of the light guide plate for a surface light emitting device thus obtained, light can be more efficiently scattered and reflected on the surface light emitting surface side of the light guide plate due to the unevenness on the back surface of the light diffusion layer 3. As a result, high-luminance surface emission was obtained.

Example 4 A polypropylene film having a surface sandblasted is used as a base sheet 2, and a light diffusion layer 3 made of an acrylic resin containing calcium carbonate as a light diffusion pigment is coated on the entire surface by a reverse coater method. And light diffusion layer 3
Using a transfer material on which an adhesive layer 4 is formed in a gradation pattern by gravure printing, a transfer material is transferred onto the back surface of the transparent light guide 1 made of an acrylic resin plate, and then the base sheet 2 is peeled off to obtain a light guide plate for a surface emitting device. It was produced (see FIGS. 4 and 8). When a line light source is arranged on the side surface of the light guide plate for a surface light emitting device thus obtained, light can be more efficiently scattered and reflected on the surface light emitting surface side of the light guide plate due to the unevenness on the back surface of the light diffusion layer 3. As a result, high-luminance surface emission was obtained.

[0023]

According to the light guide plate for a surface light emitting device of the present invention, the light diffusion layer is provided on the back surface of the transparent light guide with an adhesive layer interposed therebetween.
The transfer was performed in a turn, and the interface between the light diffusion layer and the adhesive layer and the back surface of the light diffusion layer were configured to have irregularities. The method for manufacturing a light guide plate for a surface light emitting device having the above-described configuration includes coating or printing a radiation-curable resin containing a light-diffusing pigment on a base sheet having an uneven surface, and crosslinking the radiation-curable resin by irradiation with radiation. A light diffusion layer having irregularities on the surface was formed by shrinking, a transfer material having an adhesive layer formed on the light diffusion layer was transferred to the rear surface of the transparent light guide, and then the base sheet was peeled off.

Further, in the light guide plate for a surface light emitting device of the present invention, the light diffusion layer is provided with a gradation on the back surface of the transparent light guide via an adhesive layer.
The pattern was transferred so as to have irregularities only at the interface between the light diffusion layer and the adhesive layer. The method for manufacturing a light-emitting plate for a surface-emitting device having the above-described structure includes coating or printing a radiation-curable resin containing a light-diffusing pigment on a flat base sheet, and crosslinking and shrinking the radiation-curable resin by irradiation with radiation. A light diffusion layer having irregularities on the surface was formed by using a transfer material having an adhesive layer formed on the light diffusion layer, the image was transferred to the rear surface of the transparent light guide, and then the base sheet was peeled off.

In the light guide plate for a surface light emitting device according to the present invention, the light diffusion layer is formed on the back surface of the transparent light guide in a gradation pattern.
Is copy was configured to have an uneven only on the back surface of the light-diffusing layer. The method for manufacturing a light guide plate for a surface light emitting device having the above configuration uses a transfer material having a light diffusion layer formed by applying or printing a resin containing a light diffusible pigment on a base sheet having an uneven surface. It was configured to transfer to the back surface of the light guide, and then peel off the base sheet.

In the light guide plate for a surface light emitting device according to the present invention, the light diffusion layer is provided with a gradation on the back surface of the transparent light guide via an adhesive layer.
The light diffusion layer was transferred in a pattern, and only the back surface of the light diffusion layer had irregularities. The method for manufacturing a light-emitting plate for a surface-emitting device having the above configuration includes forming a light-diffusing layer by applying or printing a resin containing a light-diffusing pigment on a base sheet having an uneven surface. Using a transfer material having an adhesive layer formed thereon, transfer was performed on the rear surface of the transparent light guide, and then the base sheet was peeled off.

Therefore, when the light guide plate for a surface light emitting device of the present invention is used in a surface light emitting device, light is more efficiently emitted due to the interface between the adhesive layer of the light diffusion layer and the light diffusion layer and / or the unevenness on the back surface of the light diffusion layer. The light can be well scattered and reflected on the surface light-emitting surface side of the light guide plate, and high-luminance surface light can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing one embodiment of a light guide plate for a surface emitting device of the present invention.

FIG. 2 is a partially enlarged sectional view showing another embodiment of the light guide plate for a surface emitting device of the present invention.

FIG. 3 is a partially enlarged sectional view showing another embodiment of the light guide plate for a surface light emitting device of the present invention.

FIG. 4 is a partially enlarged sectional view showing another embodiment of the light guide plate for a surface light emitting device of the present invention.

FIG. 5 is a partially enlarged cross-sectional view showing one embodiment of a method for manufacturing the light guide plate for a surface light emitting device of FIG. 1;

FIG. 6 is a partially enlarged cross-sectional view showing one embodiment of a method for manufacturing the light guide plate for a surface emitting device of FIG. 2;

FIG. 7 is a partially enlarged cross-sectional view showing one embodiment of a method for manufacturing the light guide plate for the surface light emitting device of FIG.

FIG. 8 is a partially enlarged cross-sectional view showing one embodiment of a method of manufacturing the light guide plate for a surface light emitting device of FIG.

FIG. 9 is a sectional view showing a light guide plate for a surface light emitting device.

FIG. 10 is a partially enlarged sectional view showing a conventional light guide plate for a surface light emitting device.

[Description of Signs] 1 Transparent light guide 2 Base sheet 3 Light diffusion layer 4 Adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 6/00 331 F21V 8/00 601 G02F 1/1335 530

Claims (8)

(57) [Claims] 1. A light diffusion layer is transferred in a gradation pattern to a rear surface of a transparent light guide via an adhesive layer, and has irregularities at an interface between the light diffusion layer and the adhesive layer and a rear surface of the light diffusion layer. Light guide plate for surface emitting device. 2. A light emitting device for a surface light emitting device, wherein a light diffusion layer is transferred in a gradation pattern to the back surface of a transparent light guide via an adhesive layer, and only the interface between the light diffusion layer and the adhesive layer has irregularities. Light board. 3. A light diffusing layer on a transparent light guide back surface Guradeshi
A light guide plate for a surface-emitting device, wherein the light guide plate is transferred in an alternative pattern and has irregularities only on the back surface of the light diffusion layer. 4. A light guide plate for a surface light emitting device, wherein a light diffusion layer is transferred in a gradation pattern to the rear surface of a transparent light guide via an adhesive layer, and only the rear surface of the light diffusion layer has irregularities. 5. A radiation-curable resin containing a light-diffusing pigment is applied or printed on a substrate sheet having an uneven surface, and the radiation-curable resin is cross-linked and contracted by irradiation with radiation to form a light having irregularities on the surface. The light guide plate for a surface emitting device according to claim 1, wherein the light guide plate according to claim 1 is formed by forming a diffusion layer, using a transfer material having an adhesive layer formed on the light diffusion layer, transferring the transfer material to the rear surface of the transparent light guide, and then peeling the base sheet. A method for manufacturing a light guide plate for a surface light emitting device, comprising: 6. A light-diffusing layer having an uneven surface by coating or printing a radiation-curable resin containing a light-diffusing pigment on a flat substrate sheet, and crosslinking and shrinking the radiation-curable resin by irradiation with radiation. 3. A light guide plate for a surface light emitting device according to claim 2, wherein the light guide plate is transferred to the back surface of the transparent light guide using a transfer material having an adhesive layer formed on the light diffusion layer, and then the base sheet is peeled off. A method for manufacturing a light guide plate for a surface light emitting device, comprising: 7. A transfer material having a light diffusion layer formed by applying or printing a resin containing a light diffusing pigment on a base sheet having an uneven surface, and transferring the resin to the back surface of the transparent light guide,
4. A method for manufacturing a light guide plate for a surface light emitting device, wherein the light guide plate for a surface light emitting device according to claim 3 is obtained by subsequently peeling the base sheet. 8. A transfer material in which a light-diffusing layer is formed by applying or printing a resin containing a light-diffusing pigment on a substrate sheet having an uneven surface, and an adhesive layer is formed on the light-diffusing layer. A method for producing a light guide plate for a surface light emitting device, wherein the light guide plate for a surface light emitting device according to claim 4 is obtained by transferring the light to the back surface of the transparent light guide and then peeling the base sheet.