JP2005309186A - Light diffusing plate, and lenticular plate and transmission type screen equipped with the light diffusing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light diffusing plate which can obtain a high-luminance, high-resolution and high-quality image without substantially causing any scintillation even when using bright light sources uniform in direction such as a liquid crystal projector as a projection source, and is used for a transmission type screen or the like, and to provide the transmission type screen equipped with the light diffusing plate. <P>SOLUTION: The light diffusing plate has three-layer structure constituted by integrally laminating a transparent plastic layer (A) formed of transparent plastic material, a middle layer (B) formed of plastic material in which diffusion material is mixed, and a transparent plastic layer (C) formed of transparent plastic material, and the front and the back surfaces of the middle layer (B) form a random wavy surface. The lenticular plate and the transmission type screen equipped with the light diffusing plate are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the field of image display technology, and is used as a screen for projection televisions, microfilm readers, and the like. In particular, scintillation does not substantially occur and high brightness, high resolution, and high quality images are obtained. The present invention relates to a light diffusing plate, a lenticular plate including the light diffusing plate, and a transmissive screen.

  Conventionally, in a rear projection type projection television, it has been required to allow a projected image to be observed brightly in a wide range on the observation side, and is widely diffused in the horizontal direction and narrower in the vertical direction. A transmission type screen having anisotropy in the visual field range, which is diffused in an appropriate range, is used.

  As such a transmissive screen, a lens such as a lenticular lens extending in the vertical direction is provided continuously on one or both sides of the sheet, and a light diffusing material is further contained in the diffusion sheet thus provided with diffusibility. In general, a lenticular lens sheet is used in which light is diffused widely in the horizontal direction by a continuous lens and light is also diffused in the vertical direction by a light diffusing material.

  The light diffusing material has a high ratio of diffused light transmittance (cloudiness value) to the total light transmittance of a transmissive screen using the light diffusing material, excellent light utilization efficiency, high color temperature, CRT and liquid crystal Performances such as see-through in which the light from a light source such as a projector is observed and a hot bar in which a partially striped bright portion is not observed are required.

Patent literature is described below.
JP 60-46503 A JP-A 61-4762 As such a light diffusing material, for example, inorganic light diffusing materials such as silica, muscovite, alumina, calcium carbonate and glass beads described in Patent Document 1, and acrylic described in Patent Document 2 are used. Amorphous organic light diffusing materials such as styrene resins, styrene resins, copolymers thereof, and silicone resins described in Patent Document 3 are used. As shown in FIG. 5, these light diffusing materials disperse the light diffusing material 82 uniformly in the lenticular lens sheet 80, or the light diffusing material 92 is disposed inside the lenticular lens sheet 90 as shown in FIG. It is used by being unevenly distributed on the emission side.

  On the other hand, as a projection image source used in combination with a transmissive screen, a liquid crystal projector using a liquid crystal panel instead of a CRT has been developed in recent years. Since this liquid crystal projector forms an image by passing or blocking light for each pixel, the light from the light source is usually made parallel light to enter the liquid crystal panel. Therefore, the light for each pixel that has passed through the liquid crystal panel is not diffused unlike the CRT that emits light for each pixel, and is light with more directivity. Moreover, since the liquid crystal panel generally used is smaller than CRT, the direction of the light for each pixel is more aligned on the screen than the CRT.

  When using a bright projection image source (light source) with a uniform orientation, such as a liquid crystal projector, an image is viewed on a transmission screen using a light diffusing material as described above. Then, there is a problem that a phenomenon called scintillation occurs in which a partial change in luminance due to the light diffusing material is clearly recognized and the entire screen is glaring. In particular, when a still image such as a computer is projected, this scintillation is felt strongly, and there is a problem that the image becomes very difficult to view.

  In order to solve such a scintillation problem, first, as a result of evaluating the influence of the particle shape of the light diffusing material on the scintillation, the spherical light diffusing material generated scintillation most remarkably. On the other hand, the irregular light diffusing material has a lower level of scintillation than the spherical light diffusing material, but cannot completely suppress the occurrence of scintillation. In addition, in the irregular diffusing material, a phenomenon of see-through of the light source called see-through occurs, which is not satisfactory as a light diffusing material for a transmissive screen. As a result of further investigation, in order to sufficiently suppress the occurrence of scintillation and to suppress the occurrence of see-through, the thickness of the light diffusion layer is increased or the screen gain is reduced, that is, the addition of a light diffusion material is added. It was found that it is necessary to increase the amount and to increase the diffusivity as much as possible. However, as the thickness of the light diffusing layer is increased, the resolving power decreases, and when the screen gain is decreased, the brightness of the projection television itself decreases. Yes.

  Accordingly, an object of the present invention is to solve the above-described conventional problems, and in the case where a bright light source having a uniform orientation, such as a liquid crystal projector, is used as a projection source, scintillation does not substantially occur and high brightness is achieved. Another object of the present invention is to provide a light diffusing plate used for a transmissive screen or the like capable of obtaining a high-resolution, high-quality image, and a transmissive screen provided with the diffusing plate.

In order to achieve the above object, that is, the invention according to claim 1,
A transparent plastic layer (A) formed from a transparent plastic material, an intermediate layer (B) formed from a plastic material mixed with a diffusion material, and a transparent plastic layer formed from a transparent plastic material A light diffusing plate having a three-layer structure in which (C) is laminated integrally;
The light diffusion plate is characterized in that the front and back surfaces of the intermediate layer (B) form random waviness surfaces.

The invention according to claim 2
When the waviness surfaces of the front and back surfaces of the intermediate layer (B) are represented by surface roughness Rm (maximum height) and Ra (centerline average roughness), the light diffusion plate having a three-layer structure integrally laminated When the thickness is D (μm) and the average particle diameter of the diffusion material mixed in the intermediate layer (B) is φ, the following expressions (1) and (2) and expression (3) are satisfied. The light diffusing plate according to claim 1.

0 <Rm <D / 10 Formula (1)
0 <Ra <D / 20 Formula (2)
And 1 μm <φ <30 μm (3)
The invention according to claim 3
A lenticular plate characterized in that a lenticular sheet is laminated on the surface of either the transparent plastic layer (A) or the transparent plastic layer (C) of the light diffusion plate.

The invention according to claim 4
A transmissive screen comprising a combination of the lenticular plate and at least a Fresnel plate.

<Action>
It consists of a light diffusion plate having a three-layer structure in which a transparent plastic layer (A), an intermediate layer (B) in which a diffusing material is mixed, and a transparent plastic layer (C) are integrally laminated. B) When random undulation surfaces are formed on the front and back surfaces of B), and the undulation surfaces are represented by surface roughnesses Rm and Ra, the thickness of the light diffusing plate having a three-layer structure integrally laminated is D ( μm), and when the average particle diameter of the diffusion material mixed in the intermediate layer (B) is φ, by satisfying the following formulas (1) and (2) and formula (3), scintillation At the same time as the generation is substantially eliminated, the thickness of the light diffusing layer can be reduced and the amount of light diffusing material added can be reduced, reducing the resolution that has been a problem in the past and reducing the screen gain. Eliminates harmful effects such as reduced brightness Is done.

0 <Rm <D / 10 Formula (1)
0 <Ra <D / 20 Formula (2)
And 1 μm <φ <30 μm (3)

  According to the present invention, the occurrence of scintillation is substantially eliminated, and at the same time, the thickness of the light diffusing layer can be reduced and the amount of the light diffusing agent added can be reduced. The adverse effects such as lowering of the brightness are eliminated.

  In addition, since the optical path difference per unit light beam is increased by the three-layer structure, speckle and scintillation can be controlled.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of the configuration of the light diffusion plate of the present invention. FIG. 2 is an explanatory view for explaining an example of a method for forming random waviness surfaces on the front and back of the intermediate layer (B) of the light diffusion plate in the present invention. FIG. 3 is a vertical sectional view showing an example of the configuration of the lenticular plate provided with the light diffusion plate of the present invention. FIG. 4 is a perspective view showing an example of a transmission screen in which a lenticular plate provided with the light diffusion plate of the present invention and a Fresnel plate are combined.

  As shown in FIG. 1, a light diffusing plate 10 according to the present invention includes a transparent plastic layer (A) 11 formed of a transparent plastic material and an intermediate formed of a plastic material mixed with a diffusing material 12a. A light diffusing plate having a three-layer structure in which a layer (B) 12 and a transparent plastic layer (C) 13 formed of a transparent plastic material are integrally laminated, the front and back of the intermediate layer (B) The light diffusing plate is characterized in that the surfaces of 12b and 12c form random waviness surfaces.

And when the waviness surface of the front and back of said intermediate | middle layer (B) is represented by surface roughness Rm (maximum height) and Ra (centerline average roughness), the said light of the three-layer structure laminated | stacked integrally When the thickness of the diffusion plate is D (μm) and the average particle diameter of the diffusion material mixed in the intermediate layer (B) is φ, the following formulas (1) and (2) and formula (3) It is characterized by satisfying.

0 <Rm <D / 10 Formula (1)
0 <Ra <D / 20 Formula (2)
And 1 μm <φ <30 μm (3)
As each plastic material forming the transparent plastic layer (A) 11, intermediate layer (B) 12, and transparent plastic layer (C) 13 constituting the light diffusion plate used in the present invention, acrylic resin, methacrylic resin, Ordinarily used transparent resins such as polycarbonate resin, polyester resin, styrene resin, acrylic-styrene copolymer resin, vinyl chloride resin, and ultraviolet curable resin can be appropriately selected and used.

  As the light diffusing material 12a mixed in the intermediate layer (B) 12 in the present invention, those conventionally used can be used, for example, from styrene resin, acrylic resin fine particles, silicone resin and the like. Inorganic fine particles made of organic fine particles or glass beads, silica, alumina, calcium carbonate, or the like can be used. As these fine particles, those having an average particle diameter (φ) of 1 to 30 μm are used. The light diffusing material may have a spherical shape or an indefinite shape, or a spherical shape and an indefinite shape may be used in combination.

  The mixing amount of the light diffusing material 12a can be appropriately set according to the screen gain required for the transmission screen and according to the thickness of the intermediate layer (B) 12 constituting the light diffusing plate. The mixing amount is 3 to 50% by weight, preferably 10 to 30% by weight.

As a method of forming waviness surfaces on the front and back surfaces 12b and 12c of the intermediate layer (B) constituting the light diffusion plate, for example, as shown in FIG. 2, the front and back waviness surfaces 12b and 12c are represented by surface roughnesses Rm and Ra. When the thickness of the light diffusion plate having a three-layer structure formed integrally is D (μm), the embossing die 20 finished to a surface satisfying the following formulas (1) and (2) is obtained. make,
0 <Rm <D / 10 Formula (1)
0 <Ra <D / 20 Formula (2)
For example, the mold surface shape is transferred and molded on one side of a transparent plastic sheet or plate constituting the transparent plastic layer (A) 11 by a heat embossing method [see FIG. 2 (a)]. Desirable is a diffusion coating made of an ultraviolet curable resin in which a transparent plastic sheet or plate 11 whose surface shape is transfer-molded is mixed with a diffusion material having an average particle diameter (φ) of 1 μm <φ <30 μm. After the intermediate layer (b) 12 'made of an uncured diffusing material mixed ultraviolet curable resin to be the intermediate layer (b) 12 is formed by uniformly applying and forming to a predetermined thickness by the coating device 30 of FIG. 2 (b)], a surface shape satisfying the above formulas (1) and (2) was transferred and molded on one side of the other transparent plastic layer (C) 13 constituting the light diffusion plate by the embossing method described above. After the transparent plastic sheet or plate 13 is placed and pressed so that the surface side is in contact with the coating surface, the intermediate layer (B) is irradiated with ultraviolet rays from the front and back of the light diffusion plate by a desired ultraviolet irradiation device 40. Cure 12 ' At the same time, the transparent plastic layer (A) 11, the intermediate layer (B) 12 ', and the transparent plastic layer (C) 13 are bonded and integrated together [see FIG. 2 (c)], thereby forming a transparent plastic material. A transparent plastic layer (A) 11, an intermediate layer (B) 12 formed of a plastic material mixed with a diffusing material, and a transparent plastic layer (C) 13 formed of a transparent plastic material, In the present invention, the front and back surfaces of the intermediate layer (B) of the light diffusion plate having a three-layer structure formed by integrally stacking are formed with random undulation surfaces satisfying the above formulas (1) and (2). The light diffusing plate 10 is obtained [see FIG. 2 (d)]. The method of forming waviness surfaces on the front and back of the intermediate layer (B) constituting the light diffusing plate is an example, and is not particularly limited to this method.

  A lenticular lens layer can be laminated on any surface of the light diffusion plate obtained above to obtain a lenticular plate provided with the light diffusion plate of the present invention.

  As an example of the above lenticular layer, as shown in FIG. 3, a convex cylindrical lens 62 is juxtaposed on one surface of a transparent substrate 61, and the convex cylindrical lens 62 is not arranged on the opposite substrate surface of the lens. A lenticular plate 50 formed by laminating a lenticular layer 60 in which a black light shielding layer 63 called a black stripe (BS) is provided in a stripe shape at a position corresponding to a light condensing portion on any surface of the light diffusion plate 10 of the present invention. Is obtained.

  The convex cylindrical lens 62 part is made of, for example, an active energy ray-curable resin cured product such as ultraviolet rays, and an active energy ray-curable resin such as ultraviolet rays is applied to the molding surface of an embossing roll mold to form a transparent substrate. 61 is supplied to an embossing roll mold, and an active energy ray such as ultraviolet rays is irradiated through the transparent base 61 to cure the resin, and at the same time, the convex cylindrical lens 62 which is a resin molding is applied to the transparent base 61. Polymerization adhesion is performed, or an active energy ray-curable resin composition is applied to the transparent base material 61, supplied to an embossing roll mold, and irradiated with active energy rays through the transparent base material 61 to cure the resin. At the same time, the cylindrical lens 62, which is a resin molded product, is molded by a method such as polymerizing and bonding to the transparent substrate 61. The present invention is not limited to. The shape of the convex cylindrical lens 62 may be circular or aspherical, and the shape is not particularly limited. The shape and dimensions of these lenticular lenses can be appropriately set according to the required performance of the transmission screen.

  The transparent substrate 61 is a transparent support for supporting the convex cylindrical lens portion, and is not particularly limited as long as it is a transparent material. However, polyethylene terephthalate (PET), polycarbonate A boat (PC) film substrate is preferred.

  Further, the black light shielding layer 63 has adhesiveness on the flat surface of the transparent substrate 61 on the side opposite to the convex cylindrical lens 62, and ultraviolet rays having such a characteristic that the adhesiveness disappears when irradiated with ultraviolet rays. A curable resin layer is applied or formed by laminating a film-like ultraviolet curable resin. Next, ultraviolet rays are irradiated through the convex cylindrical lens 62, and the viscosity of the resin is used for the uncured portion of the ultraviolet curable resin layer other than the portion which is condensed and cured by the lens action. The body toner is attached only to the uncured portion, and the black light shielding layer 63 is formed. Examples of the black powder toner include black pigments, pigments, carbon, metal salts, or black-colored acrylic resins, organic silicone resins, polystyrene, urea resins, and formaldehyde condensates, but are not particularly limited. . If necessary, two or more kinds of black powder toners may be used in combination.

  Alternatively, a black colored layer is formed by using the viscosity of the resin in the uncured portion of the ultraviolet curable resin layer other than the portion that is irradiated with ultraviolet rays through the convex cylindrical lens 62 and condensed and cured by the lens action. The transfer sheet having a color is overlapped on the colored layer side, the viscosity of the uncured portion of the resin is used to attach the colored layer only to the uncured portion, and then the cured portion of the colored layer is peeled off from the lens sheet. Thus, the black light shielding layer 63 may be formed. The transfer sheet is not particularly limited to the material and configuration of the transfer sheet as long as it is a transfer sheet having a black colored layer, and a general-purpose transfer sheet can be used.

  The lenticular lens layer 60 obtained above is easily bonded to the light diffusing plate 50 through an adhesive layer made of a light-transmitting adhesive or pressure sensitive adhesive. Can be manufactured.

  In addition, if necessary, the lenticular plate is colored, or an antireflection film is formed on the exit surface of the exit side transparent plastic layer (C) of the lenticular plate to prevent external light from being reflected and to prevent deterioration of image quality. Or a hard coat layer for the purpose of imparting scratch resistance for preventing scratches on the exit side surface. Furthermore, if necessary, a low reflection layer, a polarizing filter layer, an antistatic layer, an antiglare layer, and the like can be formed.

  The lenticular plate is colored by mixing and dispersing in a plastic material constituting the lenticular lens sheet using a dye or a fine pigment. As the color to be colored, an achromatic color such as gray or a color that selectively absorbs or transmits a specific color that controls the balance of the three primary colors (red, green, and blue) in the spectral characteristics of the light source is used. be able to. For example, by coloring the transparent plastic layer (c) 13 of the lenticular plate, the external light is absorbed more than the projection light from the light source, so that the contrast of the image can be improved.

The antireflection film can be formed, for example, on the emission surface of the transparent plastic layer (c) 13 by vapor deposition or coating. In the case of vapor deposition, a dielectric such as MgF ₂ or SiO ₂ can be used, and in the case of coating, a fluorine resin or the like can be used.

  As said hard-coat layer, it can form from the ultraviolet curable coating material in the output surface of the transparent plastic layer (c) 13, for example. UV curable coatings are generally composed mainly of polymers, oligomers, monomers, etc. that have radically polymerizable double bonds or epoxy groups in their structure as film-forming components. Contains sensitizers and sensitizers. What is preferable for the present invention is that the film-forming component uses a polyfunctional (meth) acrylate-based ultraviolet curable coating having an acrylate functional group, so that surface hardness, transparency, abrasion resistance, scratch resistance, etc. It is possible to form an excellent hard coat layer.

It can be applied by any coating method such as blade coating, rod coating, knife coating, reverse roll coating, spray coating, offset gravure coating, etc. A gravure coating, a gravure reverse coating, a reverse roll coating, an offset gravure coating method and the like excellent in properties and the like are suitable. Moreover, it can also form by transfer using the transfer sheet which made the hard-coat layer the transfer layer. The whole thickness of a lenticular board can be suitably selected by the product size to apply, for example, 1-5 mm, Preferably it is 2 It can be 4 mm. When a higher resolution is required, the thickness is preferably 3 mm or less.

  As shown in FIG. 4, the lenticular plate 50 and the Fresnel plate 70 obtained above can be combined to form a transmission screen.

  In the above transmission type screen, a front plate (not shown) or the like can be used in combination with the observation surface closest to the emission surface. As the front plate, a durable transparent resin plate is used for the purpose of preventing dust or dirt from adhering to the surface of the screen or scratching. Of course, an antistatic layer, an antireflection film, a hard coat layer, and an antiglare treatment layer can be formed on the transparent resin plate. When such a front plate is disposed and used, the above-described antistatic layer, antireflection film, hard coat layer, antiglare layer and the like formed on the emission surface of the above lenticular plate can be excluded.

  The transmissive screen of the present invention is particularly suitable when a projected image with a uniform orientation is used, such as a liquid crystal projector in which scintillation is likely to occur. High brightness, high resolution, and high quality images can be obtained.

It is sectional drawing which shows an example of a structure of the light diffusing plate of this invention. It is explanatory drawing explaining an example of the method of forming a random waviness surface in the front and back of the intermediate | middle layer (B) of the light diffusing plate in this invention. It is a vertical sectional view showing an example of the composition of the lenticular plate provided with the light diffusion plate of the present invention. It is a perspective view of the transmission type screen which combines the lenticular plate in this invention, and a Fresnel board at least. It is a vertical sectional view showing an example of a conventional light diffusing material mixed lenticular lens sheet. It is a vertical sectional view showing another example of a conventional light diffusing material mixed lenticular lens sheet.

Explanation of symbols

10 ... Light diffusion plate 11 ... Transparent plastic layer (A)
12 ... Intermediate layer (B)
12 '... Uncured intermediate layer (B)
12a, 82, 92 ... diffusion material 12b, 12c ... wavy surface black light shielding layer 13 ... transparent plastic layer (C)
DESCRIPTION OF SYMBOLS 20 ... Embossing die 30 ... Coating apparatus 40 ... Ultraviolet irradiation apparatus 50 ... Lenticular plate 60 ... Lenticular lens layer 61 ... Transparent base material 62, 81, 91 ... Convex shape Cylindrical lens 63 ... Black shading part 70 ... Fresnel plate 80, 90 ... Lenticular sheet

Claims (4)

A transparent plastic layer (A) formed from a transparent plastic material, an intermediate layer (B) formed from a plastic material mixed with a diffusion material, and a transparent plastic layer formed from a transparent plastic material A light diffusing plate having a three-layer structure in which (C) is laminated integrally;
A light diffusing plate, wherein the front and back surfaces of the intermediate layer (B) form random waviness surfaces. When the waviness surfaces of the front and back surfaces of the intermediate layer (B) are represented by surface roughness Rm (maximum height) and Ra (centerline average roughness), the light diffusion plate having a three-layer structure integrally laminated When the thickness is D (μm) and the average particle diameter of the diffusion material mixed in the intermediate layer (B) is φ, the following expressions (1) and (2) and expression (3) are satisfied. The light diffusing plate according to claim 1.
0 <Rm <D / 10 Formula (1)
0 <Ra <D / 20 Formula (2)
And 1 μm <φ <30 μm (3)   A lenticular plate characterized in that a lenticular sheet is laminated on the surface of either the transparent plastic layer (A) or the transparent plastic layer (C) of the light diffusion plate.   A transmission type screen comprising a combination of the lenticular plate and at least a Fresnel plate.

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