JPH05241243A - Transmission type screen - Google Patents

Abstract

PURPOSE:To eliminate moires without increasing constituting members and without deteriorating videos by using a Fresnel lens sheet consisting of a base material layer, an intermediate layer contg. a light diffusing agent and a lens layer. CONSTITUTION:This transmission screen consists of the Fresnel lens sheet and a lenticular lens sheet. The Fresnel lens sheet is constituted of three layers; a transparent base material layer A-1, the intermediate layer A-2 contg. the light diffusing agent and the lens layer A-3 having a lens part of a Fresnel lens shape. The lens layer A-3 is constituted of the lens part and a base part. The thickness of the base part is preferably thin. The reason thereof lies in that the intermediate layer A-2 is formed more adjacent to the lens part as the thickness of the base part is smaller, resulting in the shortened distance from the diffusion of the incident light on the screen by the light diffusing agent to the lenticular lens and the decreased out-of-focus of the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission type screen composed of a Fresnel lens and a lenticular lens used as a screen of a projection television, a micro film reader or the like.

[0002]

2. Description of the Related Art In rear projection type projection televisions, in order to obtain screen brightness and uniformity,
Further, the projection light is diffused on the screen so that a bright image can be observed to some extent even when viewed from an oblique direction. As shown in FIG. 2, the transmissive screen is composed of a Fresnel lens sheet A and a lenticular lens sheet B. The lens surface of the Fresnel lens sheet A is arranged on the light source side C, and its front surface is subjected to black stripe processing. The lenticular lens sheet B is arranged.
In the transmissive screen having such a structure, a sufficient distance exists between the lens surface (1-a) of the Fresnel lens sheet A and the lenticular lens sheet B,
Optical interference (moire) due to the Fresnel lens and the lenticular lens is less likely to occur. However, since the lens surface of the Fresnel lens sheet A is arranged on the light source side C, the incident light E incident on the non-lens surface (1-a) of the Fresnel lens is not condensed as shown in FIG. The decrease of the light quantity becomes remarkable in the peripheral part of the screen, and the observation side D
There is a problem that the peripheral part becomes dark when the image is observed at.

As shown in FIG. 4, a transmissive screen in which the lens surface (1-a) of the Fresnel lens sheet A is arranged on the side of the lenticular lens sheet B is generally used for the reduction of the light amount in the peripheral portion. Is used for. In the transmissive screen having such a structure, although the reduction in the amount of light in the peripheral portion is improved, the lens surface (1-a) of the Fresnel lens sheet A and the lenticular lens sheet B come close to each other, and the Fresnel lens and the lenticular lens have a similar structure. There is a problem that a partial moire is likely to occur due to the relationship of the lens pitch, and the image quality is deteriorated due to the moire.

For the purpose of preventing the occurrence of such moiré, as described in JP-A-59-90836, a transmissive screen having a light diffusing film arranged between a Fresnel lens sheet and a lenticular lens sheet. Is proposed. However, due to the interposition of the light diffusing film, the reflection loss at the interface with the air increases for both sides of the light diffusing film, and the entire screen becomes dark, and the number of screen components increases, which complicates the laminating process, This causes a defect such as image distortion due to a decrease in adhesion between the two.

[0005]

Therefore, as a method for suppressing the deterioration of resolution and eliminating moire without increasing the number of components of the screen, a light diffusing agent is mixed in advance in the Fresnel lens sheet. It is possible.
As a method of mixing the light diffusing agent into the Fresnel lens sheet, as shown in FIG.
A method of mixing the light diffusing agent a into the whole, a method of mixing the light diffusing agent a into the base material layer (A-1) of the Fresnel lens sheet A as shown in FIG. 6, and a Fresnel lens as shown in FIG. A method of mixing the light diffusing agent a into the lens layer (A-3) of the sheet A can be considered.

However, in the case where the light diffusing agent is mixed in the entire Fresnel lens sheet and the case where the light diffusing agent is mixed in the base material layer, the incident light incident on the screen is diffused by the light diffusing agent and then the lenticular lens. The distance to is longer and the image tends to be blurred. Further, in the case where the lens layer (A-3 ′) is mixed with a light diffusing agent, as shown in FIG.
1 and the central portion 12 have different thicknesses of the light diffusion layer, which causes a difference in brightness. Therefore, an object of the present invention is to provide a transmissive screen capable of eliminating moire without increasing the number of constituent members of the screen, deterioration of resolution.

[0007]

The inventors of the present invention have arrived at the present invention as a result of intensive studies in view of the problems of the above-mentioned prior art. That is, the transmissive screen of the present invention is a transmissive screen comprising a Fresnel lens sheet and a lenticular lens sheet, wherein the Fresnel lens sheet comprises a transparent base material layer, an intermediate layer mixed with a light diffusing agent, and a Fresnel lens. It is characterized by comprising a transparent lens layer having a lens-shaped lens portion.

As shown in FIG. 1, the Fresnel lens sheet constituting the transmissive screen of the present invention has a transparent base material layer (A-1) and an intermediate layer (A-2) containing a light diffusing agent.
And at least three layers of a lens layer (A-3) having a Fresnel lens-shaped lens portion, and an intermediate layer (A-2) includes a base material layer (A-1) and a lens layer (A-3). It is structured to be located between. Lens layer (A
(3) is composed of a Fresnel lens-shaped lens portion and a base portion, and it is preferable that the base portion has a small thickness. This is because the thinner the base portion, the closer the intermediate layer (A-2) is formed to the lens portion, and the shorter the distance from the lenticular lens after the incident light incident on the screen is diffused by the light diffusing agent. This is because the image becomes less blurred.

The thickness and material of each layer constituting the Fresnel lens sheet A are not particularly limited, but it is not preferable that the light transmittance is lowered due to coloring or turbidity. Examples of materials that can be used include plastic and glass. Specifically, acrylic resin,
Examples thereof include polycarbonate resin, polyester resin, polystyrene resin, fluororesin, polyimide resin, copolymers of these resins, and polymer alloys.

The base material layer (A-1) is preferably a plastic sheet or film having a thickness of 3 mm or less from the viewpoint of handleability and the like. In particular, a film having a thickness of 1 mm or less is preferable in view of optical characteristics such as multiple images and iridescent color spots. The intermediate layer (A-2) is a light diffusing layer in which a light diffusing agent having a refractive index different from that of the material forming the intermediate layer is mixed, and the light diffusing agent mixed is alumina, silica,
Inorganic particles such as calcium carbonate, polymer beads and the like can be mentioned. The particle size of these light diffusing agents is not particularly limited, but a particle size of about 0.5 to 30 μm is preferable. Further, a colorant such as carbon black or a neodymium compound may be mixed with the light diffusing agent to adjust the contrast of the image. The thickness of the intermediate layer (A-2) is 30% of the total thickness of the Fresnel lens sheet (A).
The following is preferable. This is the middle layer (A-2)
If the thickness exceeds 30% of the entire Fresnel lens sheet (A), the distance from the lenticular lens after the incident light that has entered the screen is diffused by the light diffusing agent becomes short, and the resolution of images such as blurring is reduced. This is because deterioration tends to occur, and more preferably 20% or less of the total thickness of the Fresnel lens sheet (A).

The lens layer (A-3) is formed by forming a Fresnel lens-shaped lens portion. The lens pattern is formed by hot press molding a thermoplastic resin film or by using an active energy ray curable resin with ultraviolet rays. It can be produced by an active energy ray curing method of curing with an active energy ray such as. Among them, the active energy ray curing method is preferable in that the lens pattern can be accurately formed and the productivity is excellent.

The active energy ray-curable resin composition is a polyvalent acrylate and / or a polyvalent methacrylate (hereinafter referred to as a polyvalent (meth) acrylate), a monoacrylate and / or a polyacrylate in view of handleability and curability. Alternatively, those containing, as a main component, monomethacrylate (hereinafter, referred to as mono (meth) acrylate) and a photopolymerization initiator by an active energy ray are preferable. Typical polyvalent (meth) acrylates include polyol poly (meth) acrylate, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, urethane poly (meth) acrylate, and the like. These are either alone or 2
Used as a mixture of more than one species. Also, mono (meta)
As acrylate, mono alcohol (mono)
Acrylic acid esters, mono (meth) acrylic acid esters of polyols, and the like can be mentioned. In the latter case, it is thought that the effect of free hydroxyl groups, but since the releasability from the metal type deteriorates, the metal type When using, it is better not to use a large amount. Further, since (meth) acrylic acid and its metal salt also have high polarity, it is better not to use a large amount when using a metal mold.

The Fresnel lens sheet of the present invention can be manufactured by a conventionally known manufacturing method. For example, as shown in FIG. 9, a transparent plastic sheet or film (9-c) corresponding to the base material layer, a plastic sheet or film (9-d) containing a light diffusing agent corresponding to the intermediate layer, and a lens. A transparent plastic sheet or film (9-c ') corresponding to the layer,
A base layer, an intermediate layer, and a lens layer are superposed in this order, and a lens die having a Fresnel lens pattern (9-a) and a mirror surface plate (9-b) are used to form a Fresnel lens layer by hot pressing. While transferring the lens shape, 3
It can be manufactured by combining two layers. In this case, the base material layer (9-c) and the intermediate layer (9-d),
Intermediate layer (9-d), lens layer (9-c '), base material layer (9
-C), the intermediate layer (9-d) and the lens layer (9-c ').
It is also possible to use a material which is previously integrated into two layers or three layers.

Further, as shown in FIG. 10, the active energy ray-curable resin liquid (10-e) is poured into a lens mold (10-a) having a Fresnel lens pattern, and a base material layer is formed thereon. A corresponding transparent plastic sheet or film (10-c) and a plastic sheet or film (10-c) in which a light diffusion agent corresponding to the intermediate layer is mixed.
After laminating a laminated sheet or film (10-b) in which d) is integrated by means such as hot pressing,
The active energy ray-curable resin (1) is irradiated by activating the active energy ray from the laminated sheet or film (10-b) side.
0-e) to form a Fresnel lens pattern, and a laminated sheet or film (10-b)
It can be manufactured by integrating with. In this case, after the active energy ray-curable resin liquid (10-e) corresponding to the lens layer is poured into the lens mold (10-a), the active energy ray is irradiated to cure or semi-cure the resin liquid to form an intermediate layer. As a layer, a resin liquid obtained by mixing an active energy ray-curable resin with a light diffusing agent is spread or poured, and a transparent plastic sheet or film (10-c) corresponding to the base material layer is superposed thereon, and the active energy ray is May be irradiated. In addition, the active energy ray-curable resin liquid (10-e) corresponding to the lens layer is applied to the lens type (10
Even if the resin liquid in which the light diffusing agent is mixed with the active energy ray-curable resin as the intermediate layer is spread or poured after being poured into -a) and the resin liquid is cured or semi-cured by irradiating with the active energy ray. Good.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A methacrylic resin cast plate (9-c) having a thickness of 2 mm (Acrylite L # 001 manufactured by Mitsubishi Rayon Co., Ltd.), average particle size 1
A 0.3 mm thick methacrylic resin film (9-d) in which 0 μm silica powder was dispersed at a concentration of 4 g / m ² (Acryprene manufactured by Mitsubishi Rayon Co., Ltd.) and a methacrylic resin film 0.3 mm thick (9-c) ') (Acryprene manufactured by Mitsubishi Rayon Co., Ltd.) is overlapped as shown in FIG. 9, and a 3 mm-thick brass lens mold (9-a) having a circular Fresnel lens pattern with a pitch of 0.1 mm and a thickness of 1 mm are used. Using a mold made of SUS mirror-finished plate (9-b), the Fresnel lens sheet having a thickness of about 2.6 mm was obtained by molding and integrating by a hot pressing method. The Fresnel lens sheet thus obtained was combined with a lenticular lens having a pitch of 0.85 mm, which was blackened on the entire surface, and was attached to a projection television as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

Example 2 An ultraviolet-transparent methacrylic resin plate (10 mm thick) having a thickness of 2 mm
-C) (Mitsubishi Rayon Acrylite L # 000)
And a 0.3 mm-thick methacrylic resin film (10-d) (acryprene manufactured by Mitsubishi Rayon Co., Ltd.) in which silica powder having an average particle diameter of 10 μm is dispersed at a concentration of 4 g / m ² are integrated by a hot pressing method. To obtain a multilayer substrate (10-b). As shown in FIG. 10, an ultraviolet curable resin liquid comprising 60 parts by weight of urethane acrylate (UK-6038 manufactured by Mitsubishi Rayon Co., Ltd.), 40 parts by weight of hydroxyethyl acrylate (Acryester HO manufactured by Mitsubishi Rayon Co., Ltd.) and 3 parts by weight of benzophenone. (10-e) was poured into the same lens mold (10-a) as in Example 1 so that the thickness would be 0.3 mm, and the multilayer substrate (10-b) was overlaid on it. Then, using three 80-Watt ultraviolet lamps, ultraviolet rays are irradiated from a position 20 mm apart on the multilayer substrate (10-a), and the ultraviolet curable resin liquid (10-e).
Was cured. Then, the lens mold (10-a) was released to obtain a Fresnel lens sheet having a thickness of about 2.6 mm.
The Fresnel lens sheet thus obtained was combined with a lenticular lens having a pitch of 0.85 mm, which was blackened on the entire surface, and was attached to a projection television as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

Example 3 Using the same method as in Example 1 except that a methacrylic resin film having a thickness of 1 mm in which silica powder having an average particle size of 10 μm was dispersed at a concentration of 4 g / m ² , a thickness of about 3. A 3 mm Fresnel lens sheet was obtained. The resulting Fresnel lens sheet and pitch 0.8 with the blackest type applied to the entire surface
A 5 mm lenticular lens was combined and attached to a projection television as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

Comparative Example 1 A methacrylic resin cast plate (Acrylite L # 001 manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 2 mm was molded by the hot pressing method using the same molding die as in Example 1, and integrated into Fresnel. I got a lens sheet. The Fresnel lens sheet obtained and a pitch of 0.5.
An 85 mm lenticular lens was combined and attached to a projection television as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

Comparative Example 2 A methacrylic resin cast plate (11-c) having a thickness of 2 mm
(Acrylite L # 001 manufactured by Mitsubishi Rayon Co., Ltd.) and silica powder having an average particle size of 10 μm dispersed at a concentration of 4 g / m ² and having a thickness of 0.3 mm.
d) (Acryprene manufactured by Mitsubishi Rayon Co., Ltd.) was overlaid as shown in FIG. 11, and the Fresnel lens sheet was obtained by molding and integrating the same molding die as in Example 1 by the hot pressing method. The obtained Fresnel lens sheet,
Pitch 0.85mm with black strike type on the entire surface
The lenticular lens of was combined and attached to a projection TV as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

Comparative Example 3 Methacrylic resin cast plate (12-c) having a thickness of 2 mm
(Acrylite L # 001 manufactured by Mitsubishi Rayon Co., Ltd.) and a silica powder having an average particle size of 10 μm dispersed at a concentration of 4 g / m ² and having a thickness of 0.3 mm.
d) (Acryprene manufactured by Mitsubishi Rayon Co., Ltd.) was superposed as shown in FIG. 12, and the Fresnel lens sheet was obtained by molding and integrating the same molding die as in Example 1 by the hot pressing method. The obtained Fresnel lens sheet,
Pitch 0.85mm with black strike type on the entire surface
The lenticular lens of was combined and attached to a projection TV as a transmissive screen, and its image and moire were observed. The results are shown in Table 1.

[0021]

[Table 1]

As shown in Table 1, the transmissive screens of Examples 1 and 2 which are the transmissive screens of the present invention are excellent in that no moiré phenomenon occurs, no blurring of images and no decrease in brightness occur. It was Further, in Example 3, the moire phenomenon did not occur, and the brightness of the image was slightly decreased as a whole, but it was not a problem in practical use. On the other hand, the transmissive screen of Comparative Example 1 was very difficult to see because the blurring of the image and the decrease in the brightness were not observed, but the moire phenomenon was remarkable. In Comparative Example 2, the moire phenomenon did not occur, but the brightness of the peripheral portion was significantly reduced, and it was difficult to see. In Comparative Example 3, the moire phenomenon occurs slightly, and the image is slightly blurred,
It was hard to see.

[0023]

The transmissive screen of the present invention comprises a substrate layer,
A Fresnel lens sheet composed of an intermediate layer and a lens layer mixed with a light diffusing agent, which is an excellent transmissive type that can eliminate moire without increasing the number of screen components and without causing image deterioration. It can provide a screen.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a Fresnel lens sheet that constitutes a transmission screen of the present invention.

FIG. 2 is a sectional view showing a structure of a conventional transmissive screen.

FIG. 3 is a schematic diagram showing incident light on a conventional transmissive screen.

FIG. 4 is a sectional view showing a structure of a conventional transmissive screen.

FIG. 5 is a cross-sectional view showing a mixed state of a light diffusing agent in a Fresnel lens sheet.

FIG. 6 is a cross-sectional view showing another mixing state of the light diffusing agent in the Fresnel lens sheet.

FIG. 7 is a cross-sectional view showing another mixing state of the light diffusing agent in the Fresnel lens sheet.

8 is a schematic diagram showing an optical path of light passing through the Fresnel lens of FIG. 7. FIG.

FIG. 9 is a schematic view showing a method for producing a Fresnel lens sheet of the present invention.

FIG. 10 is a schematic view showing a method for manufacturing the Fresnel lens sheet of the present invention.

FIG. 11 is a schematic diagram showing a manufacturing method of a Fresnel lens sheet of a comparative example.

FIG. 12 is a schematic diagram showing a manufacturing method of a Fresnel lens sheet of a comparative example.

[Explanation of symbols]

A: Fresnel lens sheet A-1: Base material layer A-2: Intermediate layer A-3: Lens layer B: Lenticular lens sheet a: Light diffusing agent 9-a: Lens type 9-b: Mirror surface plate 9-c: Plastic sheet or sheet corresponding to base layer 9-c ': Plastic sheet or sheet corresponding to lens layer 9-d: Plastic sheet or sheet corresponding to intermediate layer 10-b: Laminated plastic sheet or film 10-e: Active energy ray curable resin liquid

Claims (4)

[Claims] 1. A transmissive screen comprising a Fresnel lens sheet and a lenticular lens sheet, wherein the Fresnel lens sheet comprises a transparent base material layer, an intermediate layer mixed with a light diffusing agent, and a Fresnel lens-shaped lens section. A transmissive screen comprising a transparent lens layer having: 2. The intermediate layer containing a light diffusing agent is formed adjacent to the lens portion.
The transmissive screen described. 3. The thickness of the intermediate layer containing a light diffusing agent is
The transmissive screen according to claim 1, wherein the total thickness of the Fresnel lens sheet is 30% or less. 4. The transmissive screen according to claim 1, wherein the lens layer of the Fresnel lens sheet is formed of an active energy ray curable resin.