JP3265632B2 - Reflection type projection screen and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection screen for receiving an image projected from a projection apparatus, and more particularly to a reflection type projection screen for a liquid crystal projector and a method of manufacturing the same.

[0002]

2. Description of the Related Art A reflection type projection screen used for a liquid crystal projector or the like is required to have high luminance and good diffusion performance.

[0003] As a screen that meets this demand, there is known a screen manufactured by applying an adhesive to a sheet of plastic or the like, and then arranging small-diameter glass beads on the sheet so as to be closest packed. However, this screen has a small reflection angle and a narrow area where an image can be seen well. Also,
Due to its structure, beads are easy to fall off and dust easily accumulates on the surface, which is not practical. In particular, when this type of screen is used as a roll-up type screen, there is a problem that the glass beads gradually fall off as the screen is rolled and spread many times.

As a projection screen which has solved the above-mentioned problems, the applicant has proposed a reflection type in which a polyester film having a metal deposition layer on a base fabric and a translucent polyvinyl chloride film containing a brilliant pigment are laminated. (Japanese Utility Model Application Laid-Open No. 50842/1992). The present applicant further disclosed a metallized layer or printing on the entire surface of a plastic sheet as a projection screen having a light diffusion direction limited to a certain range. Japanese Patent Application No. 2-336654 proposes a screen in which a reflective layer having a layer formed thereon, a plastic Fresnel lens sheet, and a plastic diffusion layer containing powder of a light diffusing material are sequentially provided.

[0005] Subsequently, the applicant has proposed a reflection type projection screen in which a reflection sheet in which a number of fine concave mirrors are arranged on a base material is superposed, and the reflection sheet is made of a transparent plastic support sheet with transparent ink. By arranging a large number of fine curved projections by printing, by covering at least a part of the surface of the fine curved projections with a light reflecting material,
Either a reflective surface is formed into a concave mirror, or a plastic support sheet is formed by arranging a large number of fine secondary curved dents made of plastic, and a part of the surface of the fine secondary curved dent is formed. A reflective mirror was formed by forming a reflective surface by coating with a reflective material, and this was also proposed (Japanese Utility Model Application No. 3-144968). Although this reflection type projection sheet exhibits high performance, it cannot be denied that the step of coating with a light reflecting material increases the cost.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflection type projection screen which has both high brightness and uniform diffusivity, and further enhances the contrast of the screen to make it easier to view an image. Accordingly, it is an object of the present invention to provide a product which can be manufactured at low cost.

[0007]

According to one embodiment of the reflection type projection screen of the present invention, as shown in FIG. 1, a transparent plastic support sheet (31) is provided on a substrate (1).
A sheet (3) having a large number of fine fly-eye lens type or lenticular lens type projections (32) arranged on the surface of
A plastic adhesive layer kneaded with a brilliant pigment (2)
Wherein the interface between the projections and the adhesive layer forms a concave mirror.

The substrate (1) itself may be darkened, or a dark-colored layer (6) as shown in FIG. 1 may be provided between the substrate and the adhesive layer (2) or on the opposite side of the substrate to the adhesive layer. Is preferably provided.

In a preferred embodiment, as shown in FIG. 1, a sheet is used in which a concave portion (4) where finely curved projections are in contact with each other is filled with a light absorbing material.

Projection screens include roll-up screens and fixed screens. When a roll-up screen is manufactured, a flexible and flexible material is used as a base cloth. Use a rigid material as the substrate.

The base cloth is preferably made of glass fiber impregnated with a resin and fixed, but any woven or non-woven cloth having good dimensional stability can be used. The base fabric is required to enhance the dimensional stability of the screen, and particularly when used as a roll-up screen, to prevent the lowered screen from sagging.
Further, when the rolled-up and stored screen is used again for projection for projection, the image is distorted if the curling remains, so that the base fabric is required to have a sufficient elastic restoring property.

What best meets these requirements is a glass fiber woven fabric, particularly a glass fiber woven fabric impregnated with a resin, or a film such as polyethylene terephthalate or cellulose acetate having a large number of small holes formed by punching. A glass fiber woven fabric impregnated with a plastic such as polyvinyl chloride or phenol resin is easy to use. In addition, a nonwoven fabric of glass fiber having good dimensional stability as described above can be used. If necessary, a flexible semi-rigid polyvinyl chloride, polyethylene, polyester, etc.
Layer may be used.

As the substrate, any metal plate, wood plate or plastic plate can be used.

The color of the surface of the base material is of a white type when it is desired to increase the reflectivity of the projection screen itself and to improve the brightness, and to absorb the stray light other than the projection light even if the brightness is lowered, and to be bright. When it is desired to increase the contrast of the projection light, a black system is used.

As the support sheet, a transparent plastic sheet typified by polyester such as polyvinyl chloride, polyethylene, polypropylene, triacetyl cellulose, polycarbonate and polyethylene terephthalate may be used. Particularly, semi-rigid polyvinyl chloride is preferable from the viewpoint of flexibility and moldability. The thickness of the support sheet is arbitrary, but is usually 100 to 500 μm.
Is appropriate.

If the curved surface shape of the fine projections is specifically shown, for example, a so-called fly-eye lens as shown in FIG. 2 in which minute convex surfaces such as a spherical surface, an elliptical spherical surface, and a paraboloid of revolution are distributed over the entire surface. FIG. 3 is a diagram showing a shape, or a shape obtained by cutting a cylinder, a parabolic cylinder, an elliptic cylinder, or the like in half in the direction of a symmetric axis, and distributing the entire surface so that the vertical direction is the axial direction.
And a lenticular lens type as shown in FIG.

These projections may be formed directly on the surface of the support sheet (31) itself (the support sheet and the projections are made of the same material and are integral), or may be formed on the support sheet (31). Another transparent plastic protrusion (32)
It may be formed as. In any case, the protrusions formed on the support sheet are bonded through a plastic adhesive layer containing a brilliant pigment in a form in which the protrusions face the base material, so that the protrusions enter from the support sheet side. For light, the surface of the projection is concave.

In a projection screen, when it is desired to diffuse light in all directions of up, down, left, right, and oblique directions so that the light can be seen with the same luminance from a field of view in all directions, the above two types of lenses are used. Of these, the use of a fly-eye lens type is suitable, and the lenticular lens type is limited when a wide field of view in the vertical direction is not required for normal ornamentation, etc. This is preferable because the light amount can be efficiently diffused only to a necessary portion (front and left and right directions).
Normally, the half-value angle of light diffusion in the horizontal plane (left-right direction) (the angle at which the reflectance at an inclined angle is attenuated by half with respect to the reflectance in the direction perpendicular to the screen) is 20 ° or more, preferably 60 °. Degree is needed.

Further, in order to cope with the problem that the luminance at the periphery of the projection screen is insufficient when viewed from the front of the center, a Fresnel lens is placed in front of the projection screen, and the Fresnel lens is scattered out of the field of view from the periphery of the screen. The light that goes
What is necessary is just to make it converge in the screen center front direction. This can be said to be a diversion of a technique known for a transmission type television screen or the like.

In the case of a system in which lenticular lenses are arranged in the vertical direction, it is practically inconvenient if light is not diffused in the vertical direction at all, so that it is preferable to diffuse the light to some extent in the vertical direction. The brilliant pigment in the adhesive layer of the plastic containing the brilliant pigment functions, but when it is desired to further enhance the diffusivity, the light diffusion is performed on the flat surface of the sheet (3). As the agent, a surface diffusion layer (5) of a material obtained by adding a suitable amount of a calcite powder, a pearl pigment such as mica coated with titanium oxide, a mat material such as calcium carbonate, barium carbonate, silica or alumina to a plastic may be formed.

The size of the fine projection, that is, the radius of curvature of the concave surface is suitably about 0.2 to 3 mm. The period of the projection is determined based on the size of the projection screen, the number of pixels based on the number of scanning lines, and the like. Usually, one reflective concave mirror projection is assigned to one pixel, or one pixel is divided by several projections. As the resin used for printing for forming the projections, an appropriate resin is selected according to the forming means of the light reflecting surface.

As the brilliant pigment, a so-called "par pigment" such as powder of a metal such as aluminum or brass, or mica coated with titanium oxide is used. Average particle size 5-1
00 μm, preferably 10 to 30 μm powder or scale, 1 to 30% by weight based on plastic
It is used as the above-mentioned adhesive layer or light diffusion layer after being added to some extent.

There are various methods for producing the reflection type projection screen of the present invention. First, a sheet can be manufactured by casting or embossing a transparent plastic, and a technique called "drum printing system" disclosed in, for example, JP-A-64-6935 and JP-A-2-13117. Can be used. As a method of laminating a half mirror sheet as a base material with a plastic adhesive kneaded with a photovoltaic pigment,
First, thermal lamination is used, and a method of extruding and coating an adhesive made of a plastic such as acrylic resin, polyethylene, polypropylene, or polyvinyl chloride, or using an adhesive such as a two-component curing type polyurethane or polyester is used. Dry lamination is useful.

The drum printing system is suitable for accurately reproducing the shape and curvature of minute projections.
It is also suitable for in-line operation, in which the sheet thus produced is passed through the step of laminating it with a substrate with an adhesive kneaded with a light-emitting pigment.

The method for producing a reflection type projection sheet of the present invention using such a method comprises the following steps. 1) A roll intaglio having fine fly-eye lens type or lenticular lens type irregularities on the surface is rotated, and at least the concave portion of the roll intaglio is filled with an ionizing radiation-curable resin liquid or a thermosetting resin liquid, and is flexible and transparent. A belt-shaped support sheet made of plastic is run in synchronization with the direction of rotation of the roll intaglio and pressed against the roll intaglio. 2) Irradiating ionizing radiation or heat while rotating the roll intaglio and the support sheet synchronously. In addition, after the ionizing radiation-curable resin or the thermosetting resin is cured and simultaneously bonded to the support sheet, the support sheet and the fly-eye lens type or lenticular lens type projections formed on the surface of the support sheet are roll intaglio. And 3) feeding the belt-shaped base material and kneading the brilliant pigment. An adhesive in which the stick is extruded from an extruder and sandwiched between the protrusions of the sheet and the base material, and the protrusions of the sheet are laminated by roll pressing so as to face the plane of the base material, or a bright pigment is kneaded. And laminating the base material and the sheet so that the protrusions of the sheet face the flat surface of the base material.

Also in the projection screen of the present invention, it is preferable to provide a so-called black stripe or its equivalent to enhance the contrast of the screen.
The black stripe is formed at the portion where the fine protrusions of the sheet are in contact with each other, that is, at the portion shown by hatching in FIGS. 2 and 3.
It can be formed by printing a black ink containing a black pigment such as carbon black. More simply, it can be formed by applying black ink to the entire surface and then leaving the ink only in the recesses by wiping. The wiping is preferably performed using a flexible plastic doctor blade or air knife so as not to damage the curved projections acting like concave mirrors. Further, it is preferable to remove the ink which is thinly adhered and remains on the projections of the projections by wiping with a cloth or a roller of a sponge impregnated with a solvent.

[0027]

When projection light is incident on the reflection type projection screen of the present invention as a substantially parallel light flux from a normal line or a direction close to the normal line, the interface between the projection surface of the sheet and the adhesive layer is exposed to the incident light. As a group of concave mirrors, a part of the projection light (Li) is reflected there as shown in FIG. The reflected light once converges at the focal point of the concave mirror and then diverges, reaching the eyes of the observer as diffusely reflected light. As shown in FIG. 5, a part of the projection light transmitted through the interface is irregularly reflected by the photovoltaic pigment contained in the adhesive layer.
The sum of these two types of reflected light gives substantially uniform diffuse reflected light at a desired half-value angle, and a clear image is realized. If a light absorbing portion such as a black stripe is provided in the concave portion where the fine projections are in contact with each other, stray light (Ls) other than the projection light incident from a direction inclined with respect to the projection screen is large. The part is absorbed there and is not reflected back towards the observer. Therefore, the image becomes clearer.

When a scaly pigment is used as the brilliant pigment, the pigment scribing is performed in a form in which the sheet plane is oriented so as to be parallel to the flat surface of the scaly at the time of sheeting, that is, at the time of extrusion molding or coating. Because of the dispersion, most of the projection light that is perpendicularly incident on the projection screen is reflected by the flat surface of the scale, while stray light that is obliquely incident mostly reaches the substrate through the gap between the scales. . If the substrate is black, stray light will be absorbed by the substrate surface, so only the projected light will be reflected at a high reflectance and the stray light will be significantly attenuated. Looks like

[0029]

EXAMPLES A colorless and transparent semi-rigid (plasticizer 20 phr) polyvinyl chloride sheet (2034 mm wide, 0.1 mm thick) was used as a support sheet. An intaglio having a pattern in which protrusions formed by vertically dividing a cylinder having a diameter of 0.5 mm along its axis run in the vertical direction and the period in the horizontal direction was 1.0 mm was produced.

Using this, an ultraviolet-curable acrylic-urethane resin was printed by a drum printing method and cured by irradiating ultraviolet rays to form a columnar lenticular lens group on the surface of the support sheet.

A semi-rigid black polyvinyl chloride sheet (0.2 mm thick) of the same size as the support sheet was laminated on a glass fiber base cloth as an intermediate sheet by lamination to prepare a base material. 10 phr of titanium oxide-coated mica having an average particle size of 15 μm was added to polyvinyl chloride having the same material as that of the support sheet, and a bright pigment was kneaded to obtain an adhesive. This is melt-extruded from an extruder to form an adhesive,
The black polyvinyl chloride side of the base material and the lenticular lens side of the support sheet were laminated and adhered so as to face each other to obtain a projection screen of the present invention.

[0032]

According to the reflection type projection screen of the present invention, the image is bright and the contrast is clear. Therefore, a high-quality image can be projected on a large screen, and can be used in combination with various projection means such as a liquid crystal projector. The production can be carried out with high productivity and therefore the cost is low.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view for explaining an example of a reflection type projection screen of the present invention.

FIG. 2 is a plan view for explaining a sheet used for the reflection type projection screen of FIG.

FIG. 3 is a plan view different from FIG. 2 for explaining a sheet used in the reflection type projection screen of FIG. 1;

FIG. 4 is an enlarged sectional view for explaining the operation of the reflection type projection screen of the present invention.

FIG. 5 is a sectional view similar to FIG. 4;

[Description of Signs] 1 Base material 2 Adhesive 3 Sheet 31 Support sheet 32 Fine fly-eye lens type or lenticular lens type protrusion 4 Black printing 5 Surface diffusion layer 6 Dark layer

Claims (6)

(57) [Claims] 1. Bonding a plastic sheet kneaded with a brilliant pigment, on a base material, a sheet formed by arranging a large number of fine fly-eye lens type or lenticular lens type projections on the surface of a transparent plastic support sheet. A reflection type projection screen, wherein the projection screen and the adhesive layer are laminated so as to form a concave mirror at the interface between the projections and the adhesive layer. 2. The reflection type projection screen according to claim 1, wherein the base material itself is dark, or a dark color layer is provided between the base material and the adhesive layer or on a surface of the base material opposite to the adhesive layer. 3. The reflection type projection screen according to claim 1, wherein a sheet is used in which a concave portion in which fine fly-eye lens type or lenticular lens type projections contact each other is filled with a light absorbing material. 4. The reflection type projection screen according to claim 1, wherein a light diffusion layer made of a plastic containing a mat material or a light diffusion layer formed by embossing is provided on a flat surface of the support sheet. 5. A method for manufacturing a reflection type projection screen comprising the following steps: 1) A roll intaglio having fine fly-eye lens type or lenticular lens type irregularities on its surface is rotated to form at least a concave portion of the roll intaglio. Filling with an ionizing radiation-curable resin liquid or a thermosetting resin liquid, and running a belt-shaped support sheet made of flexible transparent plastic in synchronization with the rotation direction of the roll intaglio and pressing against the roll intaglio. 2) Irradiating or applying heat while rotating the roll intaglio and the support sheet synchronously, and after adhering to the support sheet while simultaneously curing the ionizing radiation-curable resin or thermosetting resin, the support sheet and The fly-eye or lenticular lens-shaped projections formed on the surface are released from the roll intaglio to form a sheet. And 3) feeding out the strip-shaped base material, extruding a plastic mixed with the brilliant pigment from an extruder, sandwiching the plastic between the protrusions of the sheet and the base material, and pressing the protrusions of the sheet by roll pressing. Or by laminating the base material and the sheet so that the projections of the sheet face the flat surface of the base material with an adhesive mixed with a brilliant pigment interposed therebetween. 6. The method of manufacturing a reflective projection screen according to claim 5, wherein the following steps are added between step 2) and step 3): 4) Fine fly-eye lens of the sheet Apply dark-colored ink to the surface of the mold or lenticular lens mold where the projections are present, and perform wiping to make only the recesses where the fine projections contact each other light-absorbing.