JPH1195326A - Lenticular sheet for projection screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lenticular sheet used for a transmission type screen whose contrast is high, where the loss of light is not caused, and which is inexpensive and high-definition by forming a specified light diffusion layer on a flat surface on an opposite side to the lens surface of the lenticular sheet only one surface of which a cylindrical lens group is formed on. SOLUTION: This screen is constituted by combining a Fresnel lens 1 and the lenticular sheet 2. A light diffusion sheet is laminated on a lenticular base material 5 constituted of a cylindrical lens part 3 and a transparent supporting body 4 so that the light diffusion layer 9 may be positioned on the outermost surface through a sticky layer 11 on a black stripe light shading layer 10 formed at a position equivalent to the non-condensing part of the lens part 3. The light diffusion sheet is constituted by coating the film base material 12 with light diffusion ink constituted by dispersing and blending light diffusing particulates A7 which are not colored and light diffusing particulates B8 which are colored in black in light transmissive resin 6 so that the layer 9 may be formed, and forming the sticky layer 11 on an opposite side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lenticular sheet used for a projection screen composed of a combination of a Fresnel lens and a lenticular sheet, and more particularly, to an image formed by projecting light projected from a liquid crystal projector on a transmission type liquid crystal projection television. The present invention relates to a lenticular sheet provided with a means for improving external light contrast characteristics in a diffusion layer functioning as such.

[0002]

2. Description of the Related Art A projection screen composed of a combination of a Fresnel lens and a lenticular sheet is used for a transmission type liquid crystal projection television or the like. 2. Description of the Related Art In recent years, high-quality images have been demanded along with higher definition. There are various factors that lower the quality of the image. One of the factors resulting from the projection screen used in a projection television or the like is external light reflection, reflection, glare, etc. on the surface of the screen serving as an image observation surface. Of the image quality due to a decrease in contrast caused by the image quality. In order to solve such a problem, the following proposals have conventionally been made.

[0003] Japanese Unexamined Patent Application Publication No. HEI 9 (1999) -1995 aims to improve the light use efficiency, to prevent reflection and to improve the visual field characteristics by forming fine irregularities (mat processing) on the lenticular sheet on the emission surface side of the projection light from the projector. JP-A-3-43724, JP-A-5-61120 and JP-A-7-270918 have been proposed. Although the above-mentioned proposal is intended to eliminate the reflection prevention, there has been a problem that the screen surface is whitened due to glare on the screen surface peculiar to the matte treatment and irregular reflection of external light, and the contrast is lowered.

A projection screen composed of a combination of a Fresnel lens and a lenticular sheet is separately provided with a front panel located closest to the observer, and the front panel is provided on the surface of the front panel on the incident surface side of the projection light from the projector. Japanese Patent Application Laid-Open No. 7-24 for forming a diffusion layer composed of fine particles having a light diffusing property including a black material to improve resolution, improve contrast, and improve visual field characteristics.
No. 8537 has been proposed. In the above proposal, since the outermost observation surface of the front panel is made of a transparent resin, reflection occurs, and there is a problem of lowering the contrast.
To solve this problem, the contrast is improved by forming an anti-reflection film on the outermost transparent resin surface, and the cost is reduced due to the increase in the number of front-reflection film formation steps and front panel members. There was a problem. In addition, there is also a problem of light quantity loss due to mixing and adding a black material.

Heretofore, as described above, there has been a problem in that the image is reflected on the surface of a projection screen composed of a combination of a Fresnel lens and a lenticular sheet, glare, surface reflection, and the like, and the contrast is reduced. In addition, at the same time as improving the contrast, there is a problem that the screen cost is increased due to loss of light amount and anti-reflection treatment. From such a background, there is a demand for a low-cost, high-contrast projection screen that has no loss of light quantity on the screen.

On the other hand, when the projector is a three-tube type CRT system as a transmission type projection television,
A lenticular sheet having cylindrical lens groups formed on both surfaces is used because it is necessary to correct the deviation of the three colors R, G, and B with the front and back lenses. In recent years, a transmission type liquid crystal projection television has become widespread. .

[0007] In the case of a liquid crystal projection television, there is no problem of color misregistration of RGB as compared with a three-tube CRT system due to the projection mechanism, so there is no need to use a double-sided lenticular sheet in which cylindrical lens groups are arranged on both sides. A single-sided lenticular sheet having cylindrical lens groups arranged on one side can be used.

The lenticular sheet can spread the projection light in a predetermined angle range which is the direction in which the cylindrical lenses are arranged (generally, the horizontal direction), but hardly spreads the projection light in a direction perpendicular to the direction. An auxiliary role that spreads light horizontally. In addition, a light diffusion layer is required to play a leading role in spreading light in the vertical direction. Also, in the light diffusion layer, the brightness of the central point of the incident light from the projector is locally increased so that the brightness of the screen becomes uniform, and the light diffusion layer appears as stripes in the juxtaposition direction of the cylindrical lenses. It also eliminates hot spots.

For the above reasons, a light diffusion functioning by forming an image of the projection light from the projector (and transmitting the light by diffusing the light) at any place on the projection screen composed of the combination of the Fresnel lens and the lenticular sheet. There are layers.

On the other hand, since the number of pixels of the liquid crystal projector has also increased from several hundred thousand pixels to more than one million pixels, the moiré phenomenon caused by the periodicity of the pixels of the liquid crystal projector and the periodicity of the cylindrical lens has been reduced. At the same time, the finer pitch of the cylindrical lens of the lenticular sheet is required in accordance with the higher definition of the image quality. Specifically, the lens pitch is 0.3 m.
It is necessary to achieve a fine pitch of m or less.

Accordingly, in recent years, there has been a demand for an inexpensive, high-definition, high-contrast lenticular sheet for projection screens used in liquid crystal projection televisions and the like.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and has a fine pitch only on one surface formed of a transparent resin containing no light diffusing fine particles. By applying means for improving external light contrast to the light diffusion layer formed on the flat surface opposite to the lens surface of the lenticular sheet on which the cylindrical lens group is formed, high contrast, no light loss, and low cost It is an object of the present invention to provide a lenticular sheet used for a high definition transmission screen for a liquid crystal projection television.

[0013]

The above objects can be attained by the following means. According to the first aspect of the present invention, there is provided a lenticular sheet used for a projection screen including a combination of a Fresnel lens and a lenticular sheet, wherein a flat surface opposite to the lens surface of the lenticular sheet having a cylindrical lens group formed on only one side is provided. The two types of light diffusing fine particles, the light diffusing fine particles (A) having no color on the surface and the light diffusing fine particles (B) colored black, are dispersed inside the light transmitting resin, and
It is a lenticular sheet for a projection screen having a light diffusion layer in which various types of light diffusing fine particles protrude from the surface to form irregularities.

According to a second aspect of the present invention, in the lenticular sheet for a projection screen according to the first aspect, the light diffusing fine particles (A) and (B) have an average particle diameter in a range of 1 to 10 μm. It is characterized by.

According to a third aspect of the present invention, in the lenticular sheet for a projection screen according to the first aspect, the light diffusing layer is formed by mixing the light diffusing fine particles (A) and (B) with a binder using a solvent. , A light-diffusing ink obtained by dispersion is applied to the surface of a transparent resin film, and the light-diffusing layer is bonded to the flat surface opposite to the lens surface of the lenticular sheet so that the light-diffusing layer is the outermost surface, and is laminated. It is characterized by.

According to a fourth aspect of the present invention, in the lenticular sheet for a projection screen according to the first aspect, the light diffusing layer comprises a light diffusing fine particle (A) and (B) mixed with a binder using a solvent. The lenticular sheet is formed by directly applying a dispersed light diffusion ink to a flat surface opposite to the lens surface of the lenticular sheet.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a transmission screen including a combination of a Fresnel lens (1) and a lenticular sheet (2) according to the present invention. As an example, uncolored light diffusing fine particles (A) are applied to a lenticular substrate (5) comprising a cylindrical lens portion (3) made of a cured product of an ionizing radiation-curable resin and a transparent support (4).
A light formed by dispersing and blending (7) and black light-diffusing fine particles (B) and (8) in a light-transmitting resin (6) on a film substrate (12). A light-diffusing sheet (13) including an adhesive layer (11) provided on the opposite side of the diffusion layer (9) is formed at a position corresponding to a non-light-collecting portion of a cylindrical lens portion (10). On the light diffusion layer (9) via the adhesive layer (11)
Is a lenticular sheet of the present invention having a configuration laminated so as to be positioned on the outermost surface.

FIG. 2 shows light-diffusing fine particles which are not colored.
(A) (7) and light diffusing fine particles colored in black (B)
A light-diffusing ink obtained by dispersing and blending (8) in a light-transmitting resin (6) is directly applied onto a lenticular substrate (5) on which a black stripe light-shielding layer (10) is formed, and a light-diffusing layer ( It is sectional drawing about the lenticular sheet of this invention of the structure which formed 9).

One of the configurations shown in FIGS. 1 and 2 may be appropriately selected according to the manufacturing process and required characteristics of the lenticular sheet.

The light diffusing fine particles (A) include silica,
Calcium carbonate, aluminum hydroxide, acrylic resin,
Examples thereof include an organic silicone resin, polystyrene, a urea resin, and a formaldehyde condensate, but are not particularly limited. If necessary, two or more kinds of light diffusing fine particles may be used in combination.

The light diffusing fine particles (B) include carbon black, black pigments, metal salts, or black colored acrylic resins, organic silicone resins, polystyrene,
Urea resin, formaldehyde condensate and the like,
There is no particular limitation. If necessary, two or more kinds of light diffusing fine particles may be used in combination.

The transparent support for supporting the cylindrical lens portion and the transparent film substrate for forming the light diffusion layer are not particularly limited, but are preferably polyethylene terephthalate (PET) and polycarbonate (PC) substrates. .

The light transmitting resin as a binder for dispersing and blending the light diffusing fine particles includes acrylic resin, polyurethane resin, polyester resin, polyvinyl chloride resin, polyvinyl acetate resin, cellulose resin, polyamide Examples thereof include, but are not particularly limited to, resin, fluorine resin, polypropylene resin, and polystyrene resin.

The light transmitting resin as a binder for dispersing and mixing the light diffusing fine particles is polyethylene terephthalate (a transparent support for supporting a cylindrical lens portion or a polyethylene terephthalate used as a transparent film substrate for forming a diffusion layer by coating). Acrylic resins, polyurethanes, etc., which have excellent adhesiveness and application suitability to PET), polycarbonate (PC), etc., as well as excellent dispersion suitability (wettability) of light diffusing fine particles and controllability of refractive index difference. Base resin, polyester resin, polyvinyl chloride resin, polyvinyl acetate resin, or a mixture of two or more of them.

Further, the Tg (glass transition point) of the light transmitting resin as a binder for dispersing and blending the light diffusing fine particles is as follows:
The temperature is preferably 50 ° C. or higher, and if the Tg is lower than 50 ° C., it is not preferable because, when the light diffusion layer (9) comes into contact with another member, a problem occurs in storage stability.

Generally, it is considered that the difference in refractive index between the light transmitting resin and the light diffusing fine particles is preferably 0.02 or more. When the difference in refractive index is less than 0.02, the effect of diffusing light is small, so that a large amount of addition is required, which is not preferable from the viewpoint of economical reasons or mechanical properties.

As a method for forming the light diffusing layer, a light transmitting resin and two kinds of light diffusing fine particles (A) and (B) dissolved or dispersed in an appropriate solvent are applied by a general coating method. It can be obtained by coating and drying. Light diffusing fine particles
The addition amount of (A) and (B) is desirably 1 to 20% by weight with respect to the light-transmitting resin serving as a binder, depending on the required characteristic peak gain (frontal gain) and attenuation of the gain. May be selected as appropriate. The mixing ratio is not particularly limited, and may be combined in consideration of required performance, such as fine adjustment of the angle of contrast and gain and fine adjustment of color temperature characteristics.

The adhesive layer is formed by uniformly applying an acrylic adhesive or the like, but the material of the adhesive is not particularly limited.

The light-diffusing layer has light-diffusing fine particles dispersed inside the light-diffusing layer and has irregularities protruding from the surface. The thickness of the light-diffusing layer should be as small as possible to obtain high resolution. It is preferable that a light diffusion ink in which light diffusing fine particles are dispersed is formed to a thickness of about 5 to 35 μm by a general coating method.

[0030]

【Example】

<Example 1> On one side of a 25 μm-thick polyethylene terephthalate film base material on which both surfaces were subjected to an easy adhesion treatment,
A light diffusion ink having the following composition is applied and dried to form a light diffusion layer, and then an adhesive (BPS3233D manufactured by Toyo Ink Mfg. Co., Ltd.) is applied to the other surface and dried to form a light diffusion sheet having an adhesive layer formed thereon. Was prepared. The adhesive layer side of the light diffusion sheet was laminated on the flat surface of the lenticular sheet, and the lenticular sheet was optically evaluated. The thickness of the light diffusion layer of the light diffusion sheet was 15 μm in thickness after drying, and the thickness of the adhesive layer after drying was 20 μm.

Light diffusion ink composition: 30 parts by weight of polyester resin (Byron 200 manufactured by Toyobo Co., Ltd.) 7 parts by weight of non-colored light diffusion fine particles (A) Silicone resin fine particles (Tospearl 120 manufactured by Toshiba Silicone Co., Ltd.) Black Light-diffusing fine particles (B) Crosslinked methyl methacrylate spherical fine particles (MBX-5 black manufactured by Sekisui Chemical Co., Ltd.) 3 parts by weight, methyl ethyl ketone 30 parts by weight, toluene 30 parts by weight

Example 2 A light-diffusing ink having the following composition was applied to one surface of a 25 μm-thick polyethylene terephthalate film substrate having both surfaces subjected to an easy adhesion treatment, and dried to form a light-diffusing layer. Then, an adhesive (BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) was applied to the other surface and dried to prepare a light diffusion sheet having an adhesive layer formed thereon. The adhesive layer side of the light diffusion sheet was laminated on the flat surface of the lenticular sheet, and the lenticular sheet was optically evaluated. The thickness of the light diffusion layer of the light diffusion sheet is 15 μm after drying.
m, and the film thickness of the adhesive layer after drying was 20 μm.

Light-diffusing ink composition: 30 parts by weight of acrylic resin (Dianal BR-90 manufactured by Mitsubishi Rayon Co., Ltd.) Uncolored light-diffusing fine particles (A) amorphous silica (Sycilia-446 manufactured by Fuji Silysia Chemical Ltd.) 8 parts by weight-Black light diffusing fine particles (B) Urethane beads (Art Pearl G800, Negami Kogyo Co., Ltd.) 4 parts by weight-29 parts by weight of methyl ethyl ketone-29 parts by weight of toluene

<Comparative Example 1> A light-diffusing ink having the following composition was applied to one surface of a 25 μm-thick polyethylene terephthalate film substrate having both surfaces subjected to an easy adhesion treatment, and dried to form a light-diffusing layer. Then, an adhesive (BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) was applied to the other surface and dried to prepare a light diffusion sheet having an adhesive layer formed thereon. The adhesive layer side of the light diffusion sheet was laminated on the flat surface of the lenticular sheet, and the lenticular sheet was optically evaluated. The thickness of the light diffusion layer of the light diffusion sheet is 15 μm after drying.
m, and the film thickness of the adhesive layer after drying was 20 μm.

Light-diffusing ink composition 30 parts by weight of acrylic resin (Dianal BR-60 manufactured by Mitsubishi Rayon Co., Ltd.) 4 parts by weight of amorphous silica (Silycia-446 manufactured by Fuji Silysia Chemical Ltd.) 4 parts by weight of methyl ethyl ketone 28 parts by weight・ Toluene 28 parts by weight

Comparative Example 2 A light-diffusing ink having the following composition was applied to one surface of a 25 μm-thick polyethylene terephthalate film substrate having both surfaces subjected to an easy adhesion treatment, and dried to form a light-diffusing layer. Then, an adhesive (BPS3233D, manufactured by Toyo Ink Mfg. Co., Ltd.) was applied to the other surface and dried to prepare a light diffusion sheet having an adhesive layer formed thereon. The adhesive layer side of the light diffusion sheet was laminated on the flat surface of the lenticular sheet, and the lenticular sheet was optically evaluated. The thickness of the light diffusion layer of the light diffusion sheet is 15 μm after drying.
m, the film thickness of the adhesive layer after drying was 20 μm.

Light-diffusing ink composition 30 parts by weight of acrylic resin (Dianal BR-90 manufactured by Mitsubishi Rayon Co., Ltd.) 16 parts by weight of polystyrene beads (SBX-6 manufactured by Sekisui Chemical Co., Ltd.) 16 parts by weight of methyl ethyl ketone 27 parts by weight・ Toluene 27 parts by weight

Table 1 below shows the evaluation results of the light diffusing sheets according to the above Examples and Comparative Examples and the lenticular sheets obtained by laminating the light diffusing sheets. As the lenticular sheet, a lenticular sheet having a structure suitable for a screen for a transmission type liquid crystal projection television according to Japanese Patent Application No. 8-277484 was used. That is, a convex cylindrical lens made of a cured product of an ionizing radiation-curable resin is formed (at a fine pitch) on one surface of a transparent support, and a non-condensing portion of each cylindrical lens is formed on the other surface of the support. A lenticular sheet having a structure in which a stripe-shaped light-shielding pattern is formed at a position corresponding to the above, and a light diffusion layer is formed on the pattern.

In measuring the peak gain (front gain), a laminate of a light diffusion sheet and a lenticular sheet was attached to the front of a 50-inch transmission type liquid crystal projection television, and a white signal was projected.
The luminance in the normal direction was measured from the position of m, and was calculated from a sample with a known gain. The luminance was measured using a color luminance meter BM-
7 (manufactured by Topcon Corporation) was used. To measure the attenuation of the external light contrast, a C light source is installed at a position 2 m in the normal direction of the TV screen and 2 m above the ground, and the illuminance at the center of the TV screen is 0, 100, 300 lux. It was adjusted to become. The contrast used was the luminance ratio of the black and white pattern.

The hot spot, which is a phenomenon in which the luminance at the center of the incident light becomes abnormally high and looks like a stripe, was visually evaluated at the time of peak gain measurement.

[0041]

[Table 1]

As is clear from Table 1, it was confirmed that the light diffusion layer according to the present invention was excellent as a light diffusion layer for a transmission type liquid crystal projection screen. Example 1
In Comparative Examples 1 and 2, no hot spots were observed, and the attenuation of the gain at a narrow angle was almost the same. However, the attenuation of the external light contrast with the increase in the external illuminance was small in Examples 1 and 2. It can be seen that Comparative Examples 1 and 2 are large. A light diffusion layer with little contrast decay due to external illuminance was obtained.

[0043]

According to the present invention, a lenticular sheet is formed on a flat surface opposite to a lens surface of a lenticular sheet having a fine pitch cylindrical lens group formed only on one surface formed of a transparent resin containing no light diffusing fine particles therein. In the light diffusion layer,
It consists of two types of light diffusing fine particles, ie, uncolored light diffusing fine particles (A) and black colored light diffusing fine particles (B),
The light-diffusing fine particles are dispersed in the light-transmitting resin, and a means for improving the external light contrast by forming a light-diffusing layer having projections and depressions formed on the surface is provided. 1) Due to the effect of the light-diffusing fine particles colored in black, the black luminance (the luminance value on the screen surface when the power of the television is turned off) was reduced, and the contrast was improved. (2) In the first place, the means for improving the external light contrast is applied to the light diffusing fine particles of the light diffusing layer, which is indispensable as a function by imaging (and diffusing and transmitting) the projection light from the projector. Unlike the method of coloring the screen with a black material, there is no light amount loss. (3) Light-diffusing fine particles of the light-diffusing layer, which are indispensable for the function of the screen, are provided with means for improving the external light contrast. can get. For example, it is possible to provide a low-cost, high-definition lenticular sheet used for a transmission type screen for a liquid crystal projection television, which has a high contrast, has no loss of light amount, and has a low contrast.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a transmission type liquid crystal projection screen of the present invention.

FIG. 2 is a cross-sectional view showing another example of the transmission type liquid crystal projection screen of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fresnel lens 2 ... Lenticular sheet 3 ... Cylindrical lens part 4 ... Transparent support (sheet) 5 ... Lenticular base material 6 ... Light transmissive resin 7 ... Uncolored light diffusing fine particles 8 ... Black light diffusing fine particles 9 ... Light Diffusion layer 10 Black stripe 11 Adhesive layer 12 Transparent film substrate

Claims (4)

[Claims] 1. A lenticular sheet used for a projection screen composed of a combination of a Fresnel lens and a lenticular sheet, wherein a flat surface opposite to the lens surface of the lenticular sheet having a cylindrical lens group formed on only one side is provided on a flat surface. Two types of light diffusing fine particles, a colored light diffusing fine particle (A) and a black colored light diffusing fine particle (B), are dispersed inside a light transmissive resin, and the two types of light diffusing fine particles are dispersed. A lenticular sheet for a projection screen having a light diffusion layer in which fine particles protrude from the surface and have irregularities. 2. The lenticular sheet for a projection screen according to claim 1, wherein the light diffusing fine particles (A) and (B) have an average particle diameter in a range of 1 to 10 μm. 3. The light-diffusing layer is formed by applying a light-diffusing ink obtained by mixing and dispersing light-diffusing fine particles (A) and (B) with a binder using a solvent on the surface of a transparent resin film. The lenticular sheet for a projection screen according to claim 1, wherein the lenticular sheet is laminated and laminated on the flat surface opposite to the lens surface of the lenticular sheet so that the light diffusion layer is the outermost surface. 4. The light diffusing layer comprises a light diffusing ink obtained by mixing and dispersing the light diffusing fine particles (A) and (B) in a binder using a solvent, on the side opposite to the lens surface of the lenticular sheet. 2. The lenticular sheet for a projection screen according to claim 1, wherein the lenticular sheet is directly applied and formed on a flat surface.