JP2005121811A - Optical diffusion layer transfer sheet and method for forming the optical diffusion layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer sheet which can easily provide a thin optical diffusion layer having superior optical diffusion properties on a substrate (adherend), and to provide a method for forming the optical diffusion layer using the same. <P>SOLUTION: The optical diffusion layer transfer sheet 10 includes on a support body 1: the uncured optical diffusion layer 2, which is an adhesive and which has an ionizing radiation curable resin composition and an optical diffuser having different refractive indexes with respect to the incident light; and a protective film 3. After the protective film 3 of the optical diffusion layer transfer sheet 10 is peeled off, the optical diffusion layer 2 is stuck on the adherend 20, under a pressing and heating condition. After curing the optical diffusion layer 2 by performing exposure treatment with active light rays, the support body 1 is peeled off so that the cured optical diffusion layer 2a is formed on the surface of the adherend 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light diffusion layer transfer sheet for providing a light diffusion layer to a diffusion plate or a light guide plate used in a backlight such as a liquid crystal display, and a method for forming a light diffusion layer using the light diffusion layer transfer sheet.

Light diffusing materials are used for backlights used in liquid crystal displays (hereinafter referred to as LCDs) such as notebook personal computers, televisions, and mobile phones, lighting covers, lighting signs, and display screens. In the case of an LCD backlight, the entire screen has to be irradiated with light uniformly, so a surface light source structure called a side light type or a direct type is adopted. In particular, a thin type LCD used in a notebook type personal computer or the like for which a thin and small size is desired employs a sidelight type, that is, a type of backlight that emits light from the side of the screen. In general, a light guide plate is used for the sidelight type backlight because it irradiates the entire liquid crystal display uniformly. The light guide plate is engraved with a pattern so that light incident from the side surface is emitted in the vertical direction, and the light distribution obtained by the pattern is non-uniform. Therefore, in this type of liquid crystal display, it is necessary to install a light diffusive film on the light guide plate and irradiate light uniformly in order to improve the uniformity within the screen and obtain a high quality image.
The performance required for such a light diffusion sheet includes high light transmittance, concealing the printed pattern of the light guide plate, and good color rendering, and the required optical characteristics include light emitted from the light guide plate. To spread the light emitted from the light guide plate to broaden the sight, to make the fine print pattern that can be called a light diffusive pseudo light source printed on the light guide plate invisible, etc. .

  Various light diffusion sheets used for this purpose have been proposed. For example, Japanese Patent Application Laid-Open No. 4-27501 (Patent Document 1) proposes a light diffusion sheet obtained by a process of physically forming irregularities on the surface after forming a polymer film. These light diffusing films obtain a diffusing effect by surface irregularities, and the light diffusing property depends only on the surface shape. Therefore, when the adhesive is applied to the surface of the light diffusion sheet and laminated with another base material, there is a problem that the original light diffusion property is lost. In addition, since the polymer film base material needs to have a certain thickness, the total thickness of the light diffusion sheet is increased, and there is a problem that the display cannot be made thinner. Furthermore, when a light diffusion sheet is installed on a substrate such as a light guide plate, an adhesive is required, which causes problems such as deterioration of optical characteristics and poor workability.

  Further, in JP-A-6-59108 (Patent Document 2) and JP-A-10-142406 (Patent Document 3), it is obtained by coating a polymer film with a transparent resin liquid containing a light diffusing material. Light diffusing films have been proposed. These methods have both internal diffusion due to the difference in refractive index between the transparent resin and the light diffusing agent and surface diffusion due to surface irregularities, and can provide excellent diffusibility. However, since the light diffusion layer is coated on the polymer film, this method also increases the total thickness of the light diffusion sheet and cannot cope with the thinning of the display. In addition, the light diffusion sheet is applied to a substrate such as a light guide plate. When installing, there was a problem that an adhesive was required and workability was poor. In addition, when an adhesive is applied to the surface and laminated with another substrate, the original light diffusibility may be lowered.

  In addition, among the above-mentioned problems, Japanese Patent Laid-Open No. 2002-162508 (Patent Document 4) discloses a method for improving the lamination property with another base material without utilizing the light diffusibility due to the surface shape. A sheet is proposed. That is, it is a light diffusing sheet having a smooth surface obtained by kneading a light diffusing agent into a thermoplastic resin to form a sheet and laminating resin films on both sides thereof. In this case, even if it is laminated with another base material due to the internal diffusion system, the light diffusion characteristics are hardly reduced. However, even in this method, the problem that it is difficult to reduce the thickness of the light diffusion sheet has not been solved.

JP-A-4-275501 JP-A-6-59108 Japanese Patent Laid-Open No. 10-142406 JP 2002-162508 A

  The object of the present invention is to solve the above-mentioned problems of the conventional light diffusion sheet for a light diffusion sheet used for a backlight of a liquid crystal display, and to easily form a thin light diffusion layer having a good light diffusion property. It is an object of the present invention to provide a transfer sheet that can be provided on a substrate (adherent) and a method for forming a light diffusion layer using the transfer sheet.

According to claim 1, the above-described problem has adhesiveness including an ionizing radiation curable resin composition having a different refractive index with respect to incident light and a light diffusing agent on a support directly or via a release layer. This is achieved by a light diffusion layer transfer sheet comprising an uncured light diffusion layer.
Further, according to claim 2, the release layer has a matted surface on the side in contact with the light diffusion layer, according to claim 2. Achieved.
Further, according to claim 3, the above-mentioned problem is that the light diffusion layer of the light diffusion layer transfer sheet according to claim 1 or 2 is bonded to an adherend under pressure and heating conditions, and exposed to actinic rays. After the light diffusing layer is cured, the light diffusing layer is formed on the surface of the adherend by peeling off the support or the support having the release layer. Achieved.
Further, according to claim 4, the above-described problem is that the light diffusion layer of the light diffusion layer transfer sheet according to claim 1 is bonded to an adherend under pressure and heating conditions, and has a support or a release layer. After forming an uncured light diffusing layer on the adherend by peeling off the support, a resin film is bonded onto the light diffusing layer under heat and pressure, and exposed to actinic rays for light treatment. This is achieved by a method for forming a light diffusing layer characterized in that a light diffusing layer is formed between an adherend and a resin film by curing the diffusing layer.

According to the present invention, by using a transfer sheet provided with an uncured light diffusing layer having adhesiveness on a support, the light diffusing layer is transferred and formed on a desired adherend. A thin light diffusion layer having good light diffusibility can be easily provided on the adherend without impairing the transparency. Therefore, it is effective for thinning the light diffusion sheet and improving workability.
In addition, when another member such as a prism sheet is laminated on the light diffusion layer, the uncured light diffusion layer can also serve as an adhesive layer for laminating the other member. The light diffusibility due to the internal diffusion of the light diffusion layer is not impaired.
In addition, since the light diffusion layer contains a light diffusion agent, internal diffusion can be easily adjusted by the type and blending amount of the light diffusion agent, and a release layer is interposed between the support and the light diffusion layer. By matting the surface of the release layer that is in contact with the light diffusing layer, the surface unevenness of the mat surface can be copied onto the surface of the light diffusing layer. Can be easily adjusted, and excellent light diffusibility can be imparted by internal diffusion and surface diffusion of the light diffusion layer.

Embodiments of the present invention will be described below.
As shown in FIG. 1, an embodiment of the light diffusion layer transfer sheet of the present invention includes a light diffusing agent and an uncured ionizing radiation curable resin that can be peeled from the support 1 on the support 1. The light diffusion layer 2 and the protective film 3 to be laminated are laminated. FIG. 2 shows a step of forming a light diffusion layer using this light diffusion layer transfer sheet 10. First, the protective film 3 of the light diffusion layer transfer sheet 10 is peeled off (see FIG. 2A). The light diffusing layer 2 is bonded to the adherend 20 under pressure and heating conditions (see FIG. 5B), and the light diffusing layer 2 is cured by exposure with actinic rays. The cured light diffusion layer 2a is formed on the surface of the adherend 20 (see (c) in the same figure). In this embodiment, no release layer is provided. However, in order to facilitate separation of the support 1 and the light diffusion layer 2, a release mold is provided between the support 1 and the light diffusion layer 2. It is preferred to provide a layer.

The greatest feature of the light diffusion layer transfer sheet 10 is that the light diffusion layer 2 is uncured and has adhesiveness, so that it can be bonded to various substrates by pressurization and heating and irradiated with actinic rays. As a result, the light diffusion layer 2 is cured and the adhesiveness disappears and adheres to the adherend 20. Therefore, when the support 1 is peeled off, only the light diffusion layer 2 a can be transferred to the surface of the adherend 20. Thereby, since the base film integrated with the light-diffusion layer like the conventional diffusion sheet is not required, thin film thickness becomes possible. Furthermore, since it is not necessary to attach an adhesive to a substrate such as a light guide plate like a conventional diffusion sheet, workability is good and optical properties such as light transmittance are not impaired.
Moreover, since the light-diffusion layer 2 contains the light-diffusion agent, internal diffusion can be easily adjusted with the kind and compounding quantity of a light-diffusion agent. Furthermore, by providing a release layer having a matte surface between the support 1 and the light diffusion layer 2, it is possible to copy the surface irregularities of the mat surface onto the surface of the light diffusion layer 2. Therefore, the surface diffusion of the light diffusion layer 2 can be easily adjusted. In the case of a smooth support or a smooth release layer having no mat surface, there is no surface diffusion, and a light diffusion layer depending only on internal diffusion can be obtained. That is, in the present invention, it is possible to separately adjust both the internal diffusion and the surface diffusion of the light diffusion layer, and thus good light diffusibility can be obtained.

  Further, when another member (not shown) such as a prism sheet is laminated on the light diffusion layer 2, for example, the light diffusion layer 2 of the light diffusion layer transfer sheet 10 is pressed and heated under the adherend 20. The uncured light diffusing layer 2 is formed on the adherend 20 by laminating and peeling off the support 1, and another member (resin film) is heated and pressurized under the light diffusing layer 2. The cured light diffusion layer 2a can be formed between the adherend 20 and another member by laminating below and exposing the light diffusion layer 2 by exposure treatment with actinic rays. That is, after pasting another member on the uncured light diffusing layer transferred to the adherend, the light diffusing layer can be laminated to other members by curing the light diffusing layer with actinic rays. Since it can also serve as an adhesive layer, it is effective in reducing the thickness and improving workability. In this case, since light diffusibility is obtained by the internal diffusion of the light diffusion layer, the light diffusibility is not impaired even if such other members are laminated on the light diffusion layer.

Hereinafter, the present invention will be described in more detail.
Conventionally known resin films can be used as the support used in the present invention. Examples thereof include polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, and triacetate. Polyethylene terephthalate (PET), which is excellent in mechanical strength, thermal stability and economy, is suitable. Although there is no restriction | limiting in particular in the thickness of a support body, 25-150 micrometers is preferable. This is because if the thickness of the support is too thin, wrinkles are liable to enter during bonding to the adherend, and the workability decreases, and if the thickness of the support is too thick, the rigidity of the transfer sheet increases. When pasting on the adherend, the followability to the adherend surface is reduced, and if the surface of the adherend has irregularities, bubbles are mixed. It is also economically disadvantageous.
In the present invention, in order to facilitate the transfer of the light diffusion layer, a release treatment substrate obtained by performing a release treatment on the sheet substrate may be used for the support. As such a release treatment substrate, in addition to a commercially available release film coated with silicone or Teflon, a urethane resin, a melamine resin, a fluorine resin, a silicone resin on a sheet-like substrate A release layer obtained by applying and drying a coating solution containing any of polyester resin, polyolefin resin, or a mixture thereof so that the thickness after drying is 0.1 to 10 μm, more preferably 1 to 3 μm. It can be provided and used.

  Further, a pigment can be added to the release layer to form a matte release layer. In that case, since the matting pattern is formed on the light diffusion layer coated thereon, it is possible to provide the adherend with the light diffusion layer with the outermost surface matted. That is, the outermost surface of the light diffusion layer transferred from the transfer sheet of the present invention has the same surface shape as the release surface (release surface) of the transfer sheet support. If the release surface of the support is smooth, the outermost surface of the transferred light diffusion layer is smooth. If the release surface is matte, the transferred outermost surface of the light diffusion layer is matted. Therefore, since surface diffusion can be imparted to the light diffusion layer in addition to internal diffusion, it is effective for adjusting the light diffusion property. As the pigment forming the matting release layer, the surface roughness can be adjusted by adding an inorganic pigment such as silica or a plastic pigment as a matting agent. The surface diffusion of the light diffusion layer can be adjusted by adjusting the roughness of the matting release layer surface with the pigment particle size, blending amount and release layer thickness.

The light diffusion layer in the present invention comprises a light diffusing agent and an uncured ionizing radiation curable resin composition. The ionizing radiation curable resin composition refers to a composition that cures when irradiated with ionizing radiation. Specifically, an oligomer or monomer such as an acrylate having an acryloyl group as a functional group or a methacrylate having a methacryloyl group is used. More specifically, oligomers and monomers such as urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and silicon-based (meth) acrylate can be exemplified.
Since ionizing radiation curable resins generally have low viscosity and fluidity in an uncured state, winding the transfer sheet causes problems such as the resin sticking out from the end, which is not preferable. In order to prevent this, it is preferable to adjust the cohesive force of the light diffusion layer by blending a high-viscosity ionizing radiation curable resin or blending an appropriate amount of a thermosetting resin and thermosetting it. Adhesion can be imparted to the diffusion layer. The thermosetting resin is a resin that is cured by heating, and urea resin, melamine resin, phenol resin, epoxy resin, alkyd resin, urethane resin, and the like can be used. Moreover, you may mix | blend the polyamine which has a primary or secondary amino group instead of a thermosetting resin. When a polyamine having a primary or secondary amino group is blended in an ionizing radiation curable resin, the active amine hydrogen causes an addition reaction (Michael addition reaction) with an acrylic unsaturated bond, thereby causing stickiness.

As a light diffusing agent to be blended in the light diffusion layer, inorganic fine particles such as titanium oxide, glass, silica (silicon dioxide), magnesium fluoride, magnesium carbonate, barium sulfate, magnesium sulfate, calcium carbonate, acrylic resin, silicone resin, Plastic pigments such as fluororesins, (poly) styrene resins, melamine resins, and formaldehyde condensates can be used alone or in combination of two or more.
In selecting the light diffusing agent to be used, those in which the difference in refractive index between the ionizing radiation curable resin composition and the light diffusing agent is 0.03 or more are preferable, and 0.05 or more are particularly preferable. If the difference in refractive index is too small, the light diffusion property of the light diffusion layer will be insufficient. However, if the difference in refractive index is too large, the transmittance may be lowered. In such a case, sufficient attention must be paid to the amount added.

The average particle size of the light diffusing agent is preferably 1 to 50 μm, particularly preferably 1 to 20 μm. When the particle size is too small, the transmitted light is colored, and when the particle size is too large, the transmittance is lowered, so the above range is preferable.
The proportion of the light diffusing agent in the light diffusion layer is preferably 1 to 50% by weight, particularly preferably 5 to 30% by weight. If the ratio of the light diffusing agent is small, sufficient light diffusibility cannot be obtained, and if the ratio of the light diffusing agent is too large, the adhesiveness of the light diffusing layer is lowered and the transferability to the adherend is lowered. Problems such as a decrease in transmittance occur.

In this invention, since a light-diffusion layer has adhesiveness, a protective film can be provided as needed. In order to use the transfer sheet of the present invention as a rolled-up product, the surface of the support opposite to the surface on which the light diffusing sheet is provided is subjected to release treatment, or the light after drying the release treatment film is used. Affixing to the diffusion layer is preferable from the viewpoint of work efficiency.
As the protective film, a plastic film such as polyethylene terephthalate, polyethylene, or polypropylene, or a sheet such as paper coated with a release agent such as silicone can be used. The protective film having a thickness of 4 to 200 μm can be used, but is preferably 12 to 50 μm from the viewpoint of workability. This protective film is naturally removed when the transfer sheet of the present invention is bonded to an object.

The light diffusing layer in the transfer sheet of the present invention contains a light diffusing agent and an ionizing radiation curable resin composition, but also includes a polymerization initiator, a leveling agent, a preservative, a colorant, an ultraviolet absorber, an antioxidant, An auxiliary agent such as a plasticizer can be contained to the extent that the effects of the present invention are not impaired.
In order to obtain the transfer sheet of the present invention, the release layer and the light diffusing layer on the support may be formed by using a known coater such as a bar coater, a roll coater, a kiss coater, a curtain coater, a die coater, a blade coater, or a comma coater. Can be appropriately selected and used, and can be formed by coating a coating solution for forming the layer on a support. In this case, after apply | coating a coating liquid to a support body, it can dry using well-known dryers, such as an air floating dryer and an infrared dryer.
(Example)
In order to describe the present invention in more detail, the following examples are given, but the present invention is not limited thereto. In the examples and comparative examples, all “parts” indicate parts by weight.

Using a biaxially stretched polyethylene terephthalate (hereinafter abbreviated as PET) as a support, apply the following light diffusing layer forming solution on one side with a roll coater, and dry it at 100 ° C for 1 minute. A light diffusion layer having an adhesiveness of 20 μm was formed.
<Light diffusion layer forming liquid>
Aronix M1960 (multifunctional acrylate, trade name of Toa Gosei Co., Ltd.) 14 parts Aronix M5400 (monofunctional acrylate, trade name of Toa Gosei Co., Ltd.) 14 parts Cyclo-P200 (high viscosity acrylic resin, Daicel UCB ( Product name) 6 parts Lucillin TPO (polymerization initiator, product name manufactured by BASF Japan) 1 part Tospearl T130 (silicon powder, product name manufactured by Toshiba G Silicone) 8 parts Solvent Ethyl acetate 57 parts A 25 μm thick PET film coated with silicon on one side was bonded as a protective film to the uncured light diffusion layer surface to prepare a transfer sheet. At this time, the difference in refractive index between the light diffusing agent of the light diffusing layer and the ionizing radiation curable composition was 0.09.

When the protective film of the transfer sheet obtained as described above was peeled off and bonded to an acrylic plate with a laminator, it was possible to bond without causing wrinkles. Using a high-pressure mercury lamp, the light diffusion layer with a thickness of 20 μm is easily formed on the acrylic plate by exposing from the PET support side so that the cumulative exposure at a wavelength of 365 nm is 500 mj / cm ² and peeling the PET support. It was. The 10-point average roughness of the surface of the light diffusion layer was Rz = 0.154 μm (measured with SP-500 manufactured by Toray Industries, Inc.) and a smooth surface was obtained, and the adhesion between the acrylic plate and the light diffusion layer was sufficient.
The optical properties of the acrylic plate thus provided with a light diffusing layer were measured and found to have a total light transmittance of 96% and a haze of 91% (measured with a direct reading haze meter manufactured by Toyo Seiki Co., Ltd.). It showed transparency and light diffusivity. Further, the parallel light of visible light is vertically incident from the acrylic plate side, and the luminance in the vertical direction of the light emitted from the light diffusion layer surface, which is the opposite surface of the incident portion, is L0, in a direction inclined by 30 ° from the vertical direction. Assuming that the luminance obtained in this way is L30 and the 30 ° light diffusivity is defined by the following equation (1), the light diffusivity was 2.5%.

30 ° light diffusivity (%) = (L30 / L0) × 100 (1)
Similarly to the above, the protective film of the transfer sheet is peeled off and laminated on the acrylic plate with a laminator, and then the PET support is peeled off, and then the prism sheet is laminated on the laminator, and then a high-pressure mercury lamp. When the exposure was carried out from the acrylic plate side so that the integrated exposure amount at a wavelength of 365 nm was 500 mj / cm ² using, a 20 μm thick light diffusion layer and prism sheet were easily formed on the acrylic plate.

A transfer sheet was obtained in the same manner as in Example 1 except that the light diffusion layer forming solution of Example 1 was changed as follows. At this time, the difference in refractive index between the light diffusing agent of the light diffusing layer and the ionizing radiation curable composition was 0.07.
<Light diffusion layer forming liquid>
Aronix M1960 (multifunctional acrylate, trade name of Toa Gosei Co., Ltd.) 14 parts Aronix M5400 (monofunctional acrylate, trade name of Toa Gosei Co., Ltd.) 14 parts Cycloma-P200
(High-viscosity acrylate resin, trade name of Daicel UCB) 6 parts Lucillin TPO (polymerization initiator, trade name of BASF Japan) 1 part
SX350 (styrene powder, trade name, manufactured by Soken Chemical Co., Ltd.) 8 parts Solvent Ethyl acetate 57 parts Using the obtained transfer sheet, a light diffusion layer was formed on an acrylic plate in the same manner as in Example 1. Also in this case, the 10-point average roughness of the surface of the light diffusion layer is Rz = 0.147 μm (measured with SP-500 manufactured by Toray Industries, Inc.) and a smooth surface is obtained, and the adhesion between the acrylic plate and the light diffusion layer is sufficient, When the optical properties of the acrylic plate provided with the light diffusing layer were measured, the total light transmittance was 96%, and the haze was 88% (measured with a haze meter manufactured by Toyo Seiki Co., Ltd.). . The 30 ° light diffusivity was 1.6%.

The following matting release layer forming solution was applied on one side of a biaxially stretched PET film with a thickness of 50 μm with a roll coater and dried at 130 ° C. for 1 minute to form a matting release layer with a thickness of 2 μm. .
<Matte release layer forming solution>
Tesfine 322
(Acrylamide copolymer, product name manufactured by Hitachi Chemical Co., Ltd.) 8 parts Tough Coat Medium No.6
(Epoxy-melamine copolymer, trade name of Dainippon Ink and Chemicals) 11 parts
TP145 (silicone powder, trade name manufactured by GE Toshiba Silicone) 10 parts Hair dryer 900
(Paratoluenesulfonic acid, trade name of Hitachi Chemical Polymer Co., Ltd.) 1 part Solvent 56 parts ethyl acetate
14 parts of methyl ethyl ketone The light diffusion layer forming liquid of Example 1 was applied onto the matting release layer, and the rest was performed in the same manner as in Example 1 to obtain a transfer sheet.
Using the obtained transfer sheet, a light diffusion layer was formed on the acrylic plate in the same manner as in Example 1. Also in this case, the adhesion between the acrylic plate and the light diffusing layer is sufficient, and the surface roughness of the light diffusing layer is 0.316 μm (measured with SP-500 manufactured by Toray Industries, Inc.). The mold layer was able to make the surface uneven. When the optical properties of the acrylic plate on which the light diffusion layer was formed were measured, the total light transmittance was 96%, and the haze was 92% (measured with a haze meter manufactured by Toyo Seiki Co., Ltd.). The diffusivity was improved to 5.6% due to surface irregularities, which showed very good light transmission and light diffusivity.

[Comparative Example 1]
A transfer sheet was obtained in the same manner as in Example 1 except that the light diffusion layer forming liquid of Example 1 was changed as follows. At this time, the difference in refractive index between the light diffusing agent of the light diffusing layer and the ionizing radiation curable composition is 0.02, and it can be said that there is substantially no difference.
<Light diffusion layer forming liquid>
Aronix M1960 (multifunctional acrylate: trade name made by Toa Gosei Co., Ltd.) 14 parts Aronix M5400 (monofunctional acrylate: trade name made by Toa Gosei Co., Ltd.) 14 parts Cyclo-P200 (high viscosity acrylic resin: Daicel UCB ( Product name) 6 parts Lucillin TPO (polymerization initiator: BASF Japan product name) 1 part
MX180 (acrylic beads: trade name manufactured by Soken Chemical Co., Ltd.) 8 parts Ethyl acetate (diluted solvent) 57 parts Using the obtained transfer sheet, a light diffusion layer was placed on the acrylic plate in the same manner as in Example 1. Formed. In this case, the adhesion between the acrylic plate and the light diffusion layer was sufficient, but when the optical characteristics were measured, the total light transmittance was 92%, the haze was 7%, and the 30 ° light diffusivity was It was very low as 0.003% and the light diffusibility was insufficient.

[Comparative Example 2]
The same light diffusion layer forming liquid as in Example 1 was applied to one side of a 50 μm thick PET film with a roll coater and dried at 100 ° C. for 1 minute to form a 20 μm thick light diffusion layer. Next, exposure was performed using a high-pressure mercury lamp so that the integrated exposure amount at a wavelength of 365 nm was 500 mj / cm ² to obtain a light diffusion sheet. An acrylic adhesive was applied to the acrylic plate, the light diffusion sheet was bonded with a laminator, and the light diffusion sheet was placed on the acrylic plate. When the optical properties of the acrylic plate were examined, the haze was 90% and the 30 ° light diffusivity was as good as 2.6%, but the total light transmittance was 93%, which was 3 points lower than in Example 1. This is considered to be due to the influence of the 50 μm PET film and the adhesive layer. In addition, the bonding of the light diffusing sheet to the acrylic plate is inferior in workability because an adhesive coating step is included, and the total thickness of the light diffusing sheet is as thick as 80 μm including the adhesive layer.
The data in the above Examples and Comparative Examples are summarized in Table 1 below.

It is sectional drawing which shows one Embodiment of the light-diffusion layer transfer sheet of this invention. It is sectional drawing which shows the process of forming a light-diffusion layer using the transfer sheet of one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support body 2 Light-diffusion layer 3 Protective film 10 Transfer sheet 20 Adhering body

Claims (4)

An uncured light diffusing layer having adhesiveness containing an ionizing radiation curable resin composition having a different refractive index with respect to incident light and a light diffusing agent is provided on the support directly or via a release layer. A light diffusion layer transfer sheet. 2. The light diffusion layer transfer sheet according to claim 1, wherein the release layer has a matted surface on the side in contact with the light diffusion layer. The light diffusing layer of the light diffusing layer transfer sheet according to claim 1 or 2 is bonded to an adherend under pressure and heating conditions, exposed to an active light to cure the light diffusing layer, and then a support. Alternatively, the light diffusion layer is formed on the surface of the adherend by peeling off the support having the release layer. The light diffusion layer of the light diffusion layer transfer sheet according to claim 1 is bonded to an adherend under pressure and heating conditions, and the support or the support having a release layer is peeled off to remove the uncured light diffusion layer. After being formed on the adherend, a resin film is bonded onto the light diffusing layer by heating and pressing, and the light diffusing layer is cured by performing an exposure treatment with actinic rays. A method for forming a light diffusing layer, comprising forming a light diffusing layer with a film.

Images