JPH0996871A - Production of projection screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately form black stripes in a part where no light outgoes in an image projecting screen. SOLUTION: After lenticular lens sheet 5 having lenticular lenses on one surface is formed, a photosensitive resin which can be dissolved with an org. solvent is applied on the other surface of the sheet. The lenticular lenses are irradiated with light so that the photosensitive resin 8 is selectively exposed to light by the converging function of the lenticular lenses and a mask is formed in the part where light beams are transmitted. After a light-absorbing coating material 8 is applied, the mask part is cleaned with an org. solvent and removed to form black stripes 6. Thus, the obtd. device has high contrast and small optical loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a projection screen for use in an image projection apparatus in which an image of a CRT, a liquid crystal panel or the like is enlarged and projected from the back of the screen.

[0002]

2. Description of the Related Art In recent years, there has been an increasing need for a large screen centering on a TV receiver, and a rear projection type image projection apparatus which can realize this in a relatively lightweight and compact manner is drawing attention.

FIG. 2 schematically shows a conventional basic structure. The image formed on the CRT 1 is enlarged and projected on the screen 3 by the projection lens 2. The screen 3 includes a Fresnel lens 4 and a lenticular lens 5. The Fresnel lens 4 functions to convert the projection light divergently incident on the screen 3 from the projection lens 2 into substantially parallel light. The lenticular lens 5 serves to diffuse incident light, which determines the visual field characteristics of the device.

Next, the operation of the lenticular lens 5 will be described with reference to FIG. The ray trace shown by the solid line in FIG. 3 indicates the principal ray passing through the center of the pupil of the projection lens 2, and the broken line indicates the ray passing through the peripheral portion of the projection lens.

As is apparent from the figure, the light which is incident with a sharp directivity is largely diffused, and the image can be observed from a wide visual field range.

At this time, the projection light is emitted from a specific area and is not emitted from other areas. By utilizing this, the black stripes 6 are generally formed by the light absorbing material in the non-emission area of the emission surface.

With this structure, reflection of external light can be reduced without loss of projection light, and as a result, the contrast can be greatly improved.

However, as is clear from the above description,
This black stripe must be formed in the correct position to face the incident lens. If this position shifts,
The light that should be emitted is absorbed and the light efficiency is reduced.

The screen size of this type of device, typified by a rear projection television, is typically 40 to 70 inches, while the lenticular lens pitch is 0.6 to 1.0.
mm, and in normal screen printing, a large positional deviation occurs due to a positioning error between the plate and the lenticular lens sheet and a pitch error due to a difference in expansion coefficient between the two.

Therefore, when molding a lenticular lens sheet, a method of integrally forming concave and convex on the exit surface with the lens shape of the incident surface and printing a light absorbing material on the convex surface, or a method of absorbing light on the entire surface A method has been proposed in which the material is applied and then scraped to fill only the recesses with the light absorbing material.

Specifically, when a lenticular lens sheet is press-molded or roll-molded, a mold having a lens shape on the incident surface side and a mold having an uneven pattern on the emission surface side are used. Generally, it is molded integrally.

[0012]

However, in the above-mentioned conventional configuration, the position caused by the positional error between the plate and the lenticular lens sheet and the pitch error due to the difference in expansion coefficient between the plate and the lenticular lens sheet, which is a problem when simply performing screen printing. It is possible to form the black stripes relatively accurately without causing the deviation, but the deviation of the black stripes due to the positioning error of the mold is unavoidable and causes an error of about several tens μm to 100 μm.

Further, in order to increase the above-mentioned contrast improving effect, it is advantageous to make the width of the black stripe large with respect to the lens pitch, but since such an error exists, in the conventional screen. The width of the black stripe is 40% to 50% of the lens pitch.
Was the limit.

In the case of a screen for high-definition video such as high-definition, about half of the conventional screen, 0.3 mm to 0.5 m.
Although a pitch of m is required, it has been difficult to form a black stripe in the conventional technique due to the positional deviation.

The present invention solves the above-mentioned conventional problems and provides a method of manufacturing a projection screen capable of accurately forming a black stripe and maximizing the area ratio of the black stripe to the screen. The purpose is to do.

[0016]

In order to achieve the above object, a method of manufacturing an image projection screen according to the present invention comprises forming a lenticular lens sheet having a lenticular lens on one surface and then forming an organic solvent on the other surface. The photocurable photosensitive resin that can be dissolved is applied, the light is irradiated from the lenticular lens side, and the photosensitive resin is selectively exposed by the light condensing function of the lenticular lens. After the layer is formed and developed, a light absorbing paint which is not melted by an organic solvent is applied and dried, and then the photosensitive cured resin layer is removed by the organic solvent.

[0017]

By using such a method for manufacturing an image projection screen, a black stripe can be formed at an accurate position, and a device having high contrast and small light loss can be realized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a process chart showing an embodiment of a method of manufacturing an image projection screen according to the present invention.

(A) A lenticular lens array is provided on one surface by press molding or extrusion molding,
A transparent lenticular lens sheet 5 is formed, the other surface of which is flat and whose thickness is approximately the focal length of the lenticular lens.

(B) A photocurable photosensitive resin 7 soluble in an organic solvent is applied to the flat side of the lenticular lens sheet 5.

(C) After pre-drying the photosensitive resin 7, light is irradiated from the lenticular lens surface side. At this time, the main directivity and the diffusivity of the irradiation light are set so that the irradiation light is condensed in a flat portion which is an emission surface and is substantially equal to or slightly wider than the effective emission area when used as a device. Specifically, light having a main directivity, which is the same as the projected light when used as an image projection apparatus, and light having a slightly larger diffusivity, is emitted.

(D) This is washed to remove the uncured portion. As a result, the hardened layer 7'of the photosensitive resin is formed only in the light emitting region.

(E) Light-absorbing paint 8 which is not dissolved by an organic solvent on the entire surface on which a cured layer of a photosensitive resin is formed
Apply and dry.

(F) Finally, the black stripe 6 is formed by removing the photosensitive curable resin layer 7 ′ and the light absorbing coating on the photosensitive cured resin layer 7 ′ with an organic solvent.

If it is desired to add a random diffusing action to give a diffusing action also in a direction orthogonal to the diffusing direction of the lenticular lens, use a lenticular lens having a light diffusing material dispersed therein instead of the transparent lenticular lens. Alternatively, a similar method may be used after forming the light diffusion layer on the flat surface portion of the transparent lenticular lens sheet in advance.

Further, in the above embodiment, in order to obtain the opening corresponding to the effective emission area, light having a diffusivity equal to or slightly larger than the projected light when used as a device is irradiated. However, it is also possible to use parallel light having almost no diffusivity to scan the irradiation angle within a range commensurate with the effective emission area, and it is also effective to finely adjust the aperture width by the irradiation light intensity or irradiation time. .

[0028]

As will be apparent from the detailed description above, the projection screen manufacturing method of the present invention does not cause inevitable positional displacement in the conventional method of forming irregularities using a mold. The black stripes can be formed accurately, and the area ratio of the black stripes to the screen can be maximized.

As a result, it is possible to prevent the outside light from entering the apparatus to the maximum without losing the projection light, and it is possible to realize a bright and excellent image projection apparatus.

Further, in the conventional method, it is difficult to realize a fine pitch because the axis shift is generated irrespective of the lenticular lens pitch, but according to the method for manufacturing the projection screen of the present invention, such an absolute error is generated. It is possible to realize a fine pitch screen that is compatible with high-definition video without causing a problem.

[Brief description of drawings]

FIG. 1 is a diagram showing a process in one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a basic configuration of an image projection device.

FIG. 3 is a sectional view showing the function of a lenticular lens.

[Explanation of symbols]

 5 Lenticular lens sheet 6 Black stripe 7 Light curable photosensitive resin 8 Light absorbing paint

Claims (2)

[Claims] 1. A lenticular lens is provided on one surface,
The other surface is flat, a lenticular lens sheet having a thickness approximately equal to the focal length of the lenticular lens is formed, and a photocurable photosensitive resin that can be dissolved by an organic solvent after light irradiation is applied to the flat surface of the lenticular lens sheet. Applying, irradiating light from the direction in which the lenticular lens is formed to selectively expose and cure the photosensitive resin,
After development, the uncured portion is removed to form a photosensitive resin cured film only on the light-transmitting portion, and a light-absorbing paint that does not dissolve in an organic solvent is applied to the entire flat surface and cured, and the photosensitive resin is cured by the organic solvent. A method for manufacturing a projection screen, wherein a cured resin film is removed to form a black stripe made of a light absorbing paint. 2. The method for manufacturing a projection screen according to claim 1, wherein the area of the black stripe is 50% or more of the screen area.