JPH0310498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antireflection plate that is used in cathode ray tubes, projection screens, various display devices, etc., and improves display effects by preventing surface reflection of external light.

When using a display device that uses light such as a clock that uses a solid-state light emitting device such as a cathode ray tube or a light emitting diode, or a gas discharge tube, etc., in daylight or under strong lighting, the above display device must be External light (sunlight and illumination light, etc.) is reflected on the surface of the transparent plate that covers the front, causing the plate to shine brightly, resulting in poor display contrast and poor display quality (image quality).
Sometimes things got worse.

In order to avoid the above-mentioned problems, antireflection plates shown in FIGS. 1 to 5 and described below have conventionally been used as the above-mentioned "transparent plates."

The antireflection plate shown in FIG. 1 is manufactured by a known method.
The front surface 1a of a transparent plate 1 made of transparent resin such as acrylic or glass is formed into a rough surface.

This antireflection plate randomly diffuses external light on its rough surface 1a, so it has the effect of suppressing so-called glare, but it has no effect at all attenuating the amount of external light reflected on the surface of the antireflection plate. from,
The plate surface shines brightly, weakening the contrast of the display, and the display light itself is also diffused by the rough surface 1a, making the display (image) unclear.

The antireflection plate shown in FIG. 2 is made by applying a transparent paint 3 mixed with a light diffusing material such as a matte pigment on the front surface of a transparent plate 2 made of transparent resin, glass, etc. This also has the same drawbacks as the antireflection plate.

What is shown in FIG. 3 is a so-called blind type plate, which is made by inserting a large number of flat black fillers 5 in the cross-sectional direction of a transparent resin plate 4.

The above-mentioned blind type must be manufactured by arranging a large number of transparent resin pillars and black filler alternately and then integrating them into a single pillar, which results in a complicated manufacturing process and high cost. In addition, with this type, external light (Fig. 4, B and C) that enters the board is internally reflected on the back surface 4b of the board and is emitted again to the viewer. However, since it cannot prevent reflection of external light (FIG. 4, A) on the front surface 4a of the plate, the anti-glare effect is poor. A structural plate is also known, which is made by laminating and integrating a large number of transparent plastic films having a diffusely reflective light-reflecting layer and a light-shielding layer, into a block shape, and planing the film at a right angle or at a predetermined angle to the surface of the film. However, such a plate has the disadvantage that its anti-glare effect is somewhat low due to the presence of a light-reflecting layer, and the manufacturing cost is also high.

The anti-reflection plate shown in FIG. 5 is made by laminating an extremely thin cheesecloth 7 on a transparent plate 6, and allowing the gauze 7 to absorb external light reflected by the surface 6a. However, it has poor abrasion resistance and is difficult to handle because the bonded parts tend to shift, and its uses are limited.

Furthermore, since the cross section of the fibers of the cheesecloth 7 is approximately circular, in order to more completely absorb the reflected light, etc., the area (density) of the cheesecloth 7 occupying the surface 6a must be increased. However, a large amount of display light was absorbed by the gauze 7, making the display (image) dark and difficult to see.

The present invention was made to improve the above-mentioned drawbacks of the reflector, and allows sufficient display (light) from behind to pass through, but blocks light from a different direction, while blocking external light from entering. It is an object of the present invention to provide a reflector plate and a method for manufacturing the same, which suppresses the adverse effects of reflection and enhances display effects.

The present invention will be explained below based on the drawings. As shown in FIG. 6, the reflective plate of the present invention is a front surface 8a of a transparent plate 8 made of transparent resin such as acrylic or glass.
A large number of streak-like or lattice-like light-opaque protrusions 9 made of a photocurable resin are provided on the top.
The protrusions 9 are formed by mixing a photocurable resin with a coloring agent such as a light-absorbing pigment or dye and photocuring the resin, or by photocuring the photocurable resin to form a protrusion and then using a liquid containing a colorant. However, protrusions made of a photocurable resin mixed with a colorant may be further treated with a liquid containing a colorant. The coloring agent consisting of a light-absorbing pigment or dye that can be used in the present invention may be any pigment or dye that can color the photocured photocurable resin to a light-opaque color, specifically, a blackish color. , e.g. carbon black,
Examples include triiron tetroxide and aniline black.

To explain the case where external light is incident on the antireflection plate of the present invention from an oblique direction (Fig. 7), approximately half of the external light D (portion D ₁ indicated by many dots)
Most of the light that directly hits the protrusion 9a and is absorbed by the protrusion, and also reaches the front surface 8a of the transparent plate 8, enters the transparent plate, and the remaining part (a large number of dots) is absorbed by the protrusion. The portion D ₂ ) shown is reflected by the front surface 8a and is entirely absorbed by the protrusion 9a.

Also, most of the light that enters the transparent plate above is
The remaining part is internally reflected on the back surface 8b of the transparent plate, most of it passes to the front side and is absorbed by the protrusion 9b, and only the remaining portion is reflected back to the back surface. Due to the repetition of reflection, absorption, and transmission as described above, the external light D is not reflected and does not reach the observer K. Therefore, the observer sees the display (light) E
, even if it is dark, can be clearly seen without being affected by external light. Now, assuming that the width of each protrusion 9 is 0.2 mm, the height is 0.8 mm, and the pitch between each protrusion is 1.8 mm, the ideal value of the absorption rate of the incident external light ray is 100% for incident light rays that form an angle of 45° or more with respect to the axis (the axis perpendicular to the surface of the anti-reflection plate);
Even when the incident ray is at a right angle of 30° to the optical axis,
88% or more.

Furthermore, the rate at which internal light E [display (light)] is absorbed by the antireflection plate is 11.1% when the internal light E is at an angle of 0° to the optical axis, and 50% when the internal light E is at an angle of 45° to the optical axis. %. This means that the absorption rate of external light is significantly higher than that of internal light E, and internal light (display light) E is significantly higher than external light D.
Even if it is darker or there is light from a direction different from the display light, by looking through the anti-reflection plate of the present invention from the front, the brightness advantage is reversed and the internal light E shines through. I understand that it looks like this.

Next, an embodiment of the method for manufacturing an antireflection plate of the present invention will be described. The size of the protrusion 9 on the anti-reflection plate is the same as in the above case.

First, a spacer 10 made of polyester film with a height of 0.1 mm is placed around a transparent resin plate 8 such as a transparent acrylic resin placed horizontally. The photocurable resin 9' mixed with the above-mentioned (weight ratio) is injected to the upper edge of the spacer 10 to the fullest extent. Next, as shown in FIG. 9, a negative film 11 having a large number of transparent parts 11a each having a width of 0.05 mm is placed on top of the negative film 11 and irradiated with a powerful light source 12 for several minutes. (FIG. 8) By this irradiation, the portion of the photocurable resin 9' that corresponds to the transparent portion 11a of the negative film is cured, so by removing the uncured photocurable resin by washing with water etc. A striped black protrusion 9 as shown in FIG. 6 is obtained. In addition, during the above-mentioned curing process, the black protrusions 9 are firmly fixed to the transparent resin plate 8, such as acrylic resin, and will not be peeled off by some external force. It was also confirmed that the hardened protrusions have excellent wear resistance, flexibility resistance, etc.

The protrusions of the present invention may be linear as shown in FIG. 6, or may be square or hexagonal lattice-shaped. Further, the cross section of the protrusion is usually rectangular because it is formed by exposing the light through a light-shielding film and curing the photocurable resin as described above, but it does not have to be a strict rectangle. Further, the transparent plate may have a curved surface to match the surface of the cathode ray tube depending on the purpose, for example, when the purpose is to prevent glare from external light of the cathode ray tube. The size and shape of each protrusion and the spacing between them can be determined by taking into consideration the direction and angle from which the display light is viewed.

As explained above, the anti-reflection plate of the present invention can almost completely prevent reflection of external light, and can obtain display effects with excellent contrast etc. even in bright places without being affected by external light. Therefore, it is particularly effective when used not only in cathode ray tubes, various (electronic) display devices, and rear projection screens, but also in power-saving display devices that use relatively low-luminance light-emitting elements.
In addition, the structure is simple, easy to manufacture, and the manufacturing cost is low, making it suitable for mass production. Therefore, the antireflection plate of the present invention can be effectively used in, for example, ordinary projection screens, road sign boards, show windows, various displays, etc. in addition to the above, and has an extremely wide range of applications.

[Brief explanation of drawings]

1, 2, and 5 are sectional views of a conventional antireflection plate, FIG. 3 is a perspective view of a conventional blind mold plate, and FIG. 4 is a sectional view of FIG. 3. 6 is a perspective view of one embodiment of the present invention, and FIG. 7 is an explanatory view for explaining the operation of FIG. 6. FIG. 8 is an explanatory diagram of the method for manufacturing an antireflection plate of the present invention, and FIG. 9 is a front view of the negative film in FIG. 8. 8...Transparent plate, 9...Protrusion, 10...Spacer, 11...Negative film, 12...Light source.

Claims (1)

[Scope of Claims] 1. An antireflection plate in which a large number of streak-like or lattice-like light-impermeable projections made of a photocurable resin are fixed to the surface of a transparent plate. 2. Forming a photocurable resin layer mixed with or without a light-absorbing colorant on a transparent plate,
It is exposed to light through a light-shielding film that transmits light through a large number of striped or lattice-like patterns to form projections made of a photocurable resin on the transparent plate, and then, as necessary, the projections are A reflective film in which a large number of streak-like or lattice-like light-impermeable protrusions made of a photocurable resin are fixed to the surface of a transparent plate that is treated with a liquid containing a light-absorbing colorant. Manufacturing method of prevention plate.