JPS6079342A - Transmission type screen - Google Patents

Abstract

PURPOSE:To manufacture easily a titled screen and also to improve the contrast of a picture by making adhere to arrange a light absorptive threaded substance covered with an adhesive agent to a long and slender groove formed along the dark stripe part of an observation surface. CONSTITUTION:Because of a refracting and condensing action of a long and slender lens 21, a bright stripe part 3a passing a light to a vertical direction and a dark stripe part 3b not passing a light are formed alternately in parallel on the observation surface 3. In order to raise the contrast of a video, the part obtaining the bright stripe 3a of the observation surface 3 of a transmission type screen 1 is provided with the long and slender groove 31 along it to obtain the dark stripe part 3b as a light absorbing and shielding part, and the threaded substance 32 covered with an adhesive agent is inserted into the groove 31 to be made adhered and arranged. The threaded substance 32 is not specifically limited so far it has a light absorbing ability and prescribed strength, and its circumference is covered with an adhesive agent 32a. The adhesive agent 32a having good transparency or colored to a dark color system will to, but to make the most of the feature of the threaded substance 32 having uniform size, the adhesive with good transparency is desirable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission screen, and more particularly to an improvement in a transmission screen provided with light-absorbing stripes to improve image contrast.

Various types of transmissive screens have been proposed for use in video screens of video projection televisions, etc., and some of them are already in use.

Video projection television projects images of large children onto its video screen, and is mainly used to allow viewing by a large number of viewers at once. In order to enable viewing by a large number of viewers, it is necessary to use a video screen with a wide viewing angle, and lenticular screens are preferably used for this purpose.

A lenticular screen is a screen in which a large number of elongated lenses, such as cylindrical lenses, are arranged on at least one side, with their longitudinal axes almost parallel. It refracts and focuses the light, and then diffuses and emits the light within a specific angular range from the observation surface. This lenticular screen is made of a large number of long and narrow lenses arranged in a row, so the front side of the lenticular screen is divided into two parts: one is a bright part through which light passes, and the other is a bright part through which light passes, due to the refraction and focusing effect of the long lenses. Dark areas appear. In other words, in front of the lenticular screen, due to the transmitted light,
A large number of parallel bright and dark stripes result. Generally speaking, in a transmission screen having one surface having a lens effect, there are bright areas through which light passes and dark areas through which light does not pass, on the viewing side.

It is preferable that the video projection screen can also be used in a so-called bright room where there is fairly bright outside light. However, when external light hits the image area of the video projection screen, the image area that displays dark areas such as black is brightly illuminated, reducing the contrast of the image.

Generally, the image contrast of a video projection screen is defined as: DMAX + Bs contrast C = □ BMlN + B2.

BMAX: Brightness of the bright part of the image BM Engineering N: Brightness of dark areas of the image Bl: Reflection brightness of external light in bright areas B2: Reflection brightness of external light in dark areas It is.

In a dark room with no outside light, increasing the MAX/BMIN ratio will improve the contrast, but in a bright room where outside light is affected, the reflected brightness (Bl) of outside light (Bz) must be taken into account. .

In other words, K, which enhances the contrast of the image on the video projection screen itself, is the reflected brightness of external light on both sides (
Bl, B2) It is to minimize the amount of external light transmitted into the video projection screen.In other words, it is to increase the amount of external light that passes into the video projection screen and give the video projection screen the ability to absorb external light. for,
The method is to completely scatter a light-absorbing substance on the screen base material or to provide a light-absorbing portion on the surface of the screen.

For example, Japanese Unexamined Utility Model Publication No. 49-3528 proposes attaching a light-impermeable network made of photoresist to the viewing surface or projection surface of the screen. However, in the structure of this Kakai Publication No. 49-3528,
Since the absorber gold film shields the light tube including the original transmitting part of the screen, the transmitted image of the transmitted light to be imaged is also reduced, which is advantageous for use as this type of screen. It can not be said.

Japanese Patent Publication No. 52-46693 proposes that a light-shielding stripe portion be provided on the opposite side of a transmissive video projection screen that has a lenticular structure consisting of a large number of cylindrical lenses on one side where light does not pass through to increase contrast. has been done. This special public service 52-466
The configuration disclosed in Japanese Utility Model Publication No. 93 is very advantageous for use as a video projection screen when compared with the configuration disclosed in Japanese Utility Model Application No. 49-3528. This is because there is no problem of blocking transmitted light for images.

The video projection screen disclosed in Japanese Patent Publication No. 52-46695 is provided with a photoresist film on the opposite side of the entire lenticule of the lenticular screen, and this film is exposed, developed, and dried so that no light passes through the opposite side. A stripe pattern of a photoresist film is entirely formed, leaving only a portion of the photoresist film, and an oil-based ink is applied onto the stripe pattern using offset printing or the like to form a light-shielding portion.

However, printing oil-based ink on a striped pattern as described above requires a fairly sophisticated printing technology and requires complicated steps. This is because the stripes in the stripe pattern are very thin, and it is necessary to accurately align the ink application nose. In addition, the photoresist film must go through a process of exposure, development, and drying, which necessitates work in a dark room to manufacture the video projection screen, complicating the manufacturing process, and the adhesion of the photoresist film is poor. Extreme care must be taken, which necessarily increases production costs.

A method of directly printing or painting on the portions of the video projection screen through which light does not pass could be considered, but uneven printing is likely to occur, and as mentioned above, it is difficult to paint with a narrow and uniform width.

From this point of view, the present inventors have developed a video glossier that has excellent performance such as contrast and is easy to manufacture, by utilizing the grooves of the dark stripe portion on the observation surface and arranging a thread-like material as a light absorber within the grooves. It has already been proposed to provide a transparent screen for
34409), but the present invention further seeks to improve the stability of this filament.

That is, the gist of the present invention is to provide a transmission screen having a projection surface and an observation surface, in which at least 10,000 surfaces of the projection surface and the observation surface are formed to have a lens function, and the projection surface is In a transmissive screen configured so that the light projected onto the viewing surface defines a large number of bright striped portions through which the light passes and dark striped portions through which the original light does not pass, the light projected onto the viewing surface overflows into the dark striped portions of the viewing surface. This is a transmissive type screen 1-none characterized by forming elongated grooves and adhering and disposing light-absorbing filamentous materials coated with an adhesive in these elongated grooves.

The base material constituting the transmission screen of the present invention includes acrylic resin, vinyl chloride resin, polycarbonate resin,
Materials such as olefin resins and styrene resins are used, and the products of the present invention are manufactured by extrusion molding, hot pressing, or injection molding. Therefore, the large number of elongated grooves to be formed on the observation surface of the above-mentioned transmission screen can be easily formed at the same time as the lens action surface. Further, the arrangement of the filamentous substances in the large number of elongated grooves can be easily performed by arranging the filamentous substances in advance at intervals equal to the arrangement spacing of the elongated grooves.

Note that it is also effective to add a diffusing agent to the base material constituting the transmission screen of the present invention to supplement the vertical diffusivity of the screen. The diffusing agent at this time is 5i02.
At203. At(OH)3. BaSO4゜Ti
Examples include O2, 0a003, and the like. Similarly, if a light-absorbing colorant such as carbon black or aniline black is added to this base material, either in combination with a diffusing agent or alone, the brightness of the screen can be adjusted. However, if a large amount of vinegar is added to this light-absorbing colorant,
Since the transmittance of the screen decreases, the total light transmittance is 6.
It is desirable to add about 10 to 20 ppm so that it does not become less than 0%.

The invention will be explained in more detail below by way of example and with reference to the accompanying drawings, in which: FIG.

FIG. 1 schematically shows a video projection device, in which a transmission screen (1) of the present invention has a projection surface (2) on which projection light is projected from a video projector (P). The projection surface (2) is a lenticular lens surface provided with a number of elongated lenses (21) whose longitudinal axes extend in the vertical direction. The projection light is refracted and condensed by the elongated lens (21) and emitted from the observation surface (6) while being uniformly distributed over a predetermined angle range in the horizontal direction. , on the observation plane (3),
Bright stripe portions (3a) through which light passes in the vertical direction and dark stripe portions (3b) through which light does not pass are alternately formed in parallel.

In order to increase the contrast of the image, the dark stripe part C0b)'fr is used as an original light-absorbing part. The dark stripe (3a) of the observation surface (3) is provided with elongated grooves (3a) along the dark stripe (3a), and these grooves are inserted and bonded.

The filamentous material (52) used in the present invention is particularly limited as long as it has light absorption ability, has a predetermined strength, and is coated with an adhesive (32a) around the periphery as shown in FIG. Not done. For example, spun yarns or filament yarns made of natural fibers or synthetic fibers that are dyed in dark colors are common, but instead of these fiber yarns, metal fiber yarns such as Ic aluminum or ultra-fine metal wires such as piano wire are used. Articles etc. are available. In addition, the adhesive (32a) at this time may be one with good transparency or one with a dark VC color.
In order to take advantage of the characteristics of the thread-like material (32) having a uniform diameter, it is preferable to use a transparent material. For example, a solvent-based adhesive (52)
Types of a) include vinyl acetate, acrylic, and urethane adhesives, but so-called hot melt type adhesives can also be used. Hot-melt type adhesives include polyamide, butyl rubber, olefin, and ethylene-vinyl acetate (gvA) adhesives, but EVA adhesives are particularly preferred because they can be bonded at temperatures below 100°C and are transparent. O As mentioned above, light-absorbing yarn material (32) is used as a light absorber.
e. Light-absorbing and shading portions with a constant uniform width are placed in the exact position by a simple method of arranging them in the elongated grooves (31) of the observation surface (3) of the transmission screen (1) using the adhesive gold. can be provided, and its position is stable without shifting. Therefore, unlike conventional transmission screens, there is no need to print and paint the light absorbing/collecting portions, and the complicated steps associated therewith can be omitted.

Figure f54 shows another embodiment in which lenticules are provided on both sides of the transmission screen (the observation surface (
A thread-like material (32) is provided between the elongated lens bodies (33) of 3) in the same manner as in FIG.

Figures 5 and 6 show an elongated lens body (with a shape different from that in Figure 3) only on the viewing surface (3) of the transmission screen (1).
35), (36) This is an embodiment in which a lenticule in which a plurality of transistors are arranged is provided. These lens bodies (35).

In (56), the inclined surfaces on both sides of each lens unit are total reflection surfaces, and no light is emitted from these surfaces, forming a dark stripe portion. Furthermore, such a lens body (35)
, (36)', the transmission type screen provided with lenticules is disclosed in Japanese Patent Application No. 56-51194 filed by the same applicant.
No., Patent Application No. 1982-91896, Patent Application No. 1983-2125
No. 84, Japanese Patent Application No. 56-29178, Japanese Patent Application No. 57-59
389.

FIG. 7 is an enlarged view of the viewing surface of the transmission screen shown in FIG. 5, and shows the shape of a specific lenticular lens, so the explanation will be based on this example (the units are lenticular lenses). For example, when an acrylic resin with a refractive index of 1.492 is used as the base material, the angle of the total reflection surface is required to be approximately 69° or more, but in this example, as shown in the figure, it is configured with an IC of 72.5°. Therefore, light rays that are incident parallel to this total reflection surface are totally reflected on the total reflection surface and emitted from the top of each lens, but some of the light is emitted at a large angle, resulting in a wide viewing angle as a whole. will be obtained. However, if a substance with a high base material F refractive index or a light-absorbing substance adheres to this total reflection surface, light that should be totally reflected will be transmitted or absorbed here. However, when the light-absorbing filament (32) is bonded to the light-absorbing filament (32) using the method of the present invention, the outer surface of the total reflection surface is almost an air layer, so that the light incident on the total reflection surface is The light beam (3) is totally reflected without being affected by the light-absorbing filament (32).

When a light-absorbing filament (32) coated with a hot-melt adhesive is used and the adhesive is melted, the thin layer of the adhesive may slightly scratch the total reflection surface. Even if only a part of the light is affected, as shown by ■ in Figure 7, there is no real problem, and even in such cases, there is no problem at all if the thickness of the light-absorbing filament (32) is taken into consideration. It can be configured as follows.

In addition, in the transmission type screen shown in FIG. 5 and FIG. 6, a Fresnel lens (22) is formed on the projection surface (2).
2) Since it refracts the incident light into parallel light and focuses it on a predetermined spot on the observation side, it maintains the brightness especially around the screen and makes the screen uniform. It is useful for For this reason, the embodiment shown in FIG. 8 uses a separate Fresnel lens sheet (4) as a fourth lens sheet.
This is an example arranged on the projection side of the screen shown in the figure.

Although the present invention has been described above in detail in the form of examples, the present invention is not limited to the above-mentioned examples, and can be variously modified within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a video glodictor device, FIG. 2 is a partially sectional view showing a transmission screen which is an embodiment of the present invention, and FIG. Figures 4 to 6 illustrating absorbent threads in enlarged cross-sectional views;
7 is a partially enlarged sectional view showing the observation surface of the transmission screen shown in FIG. 5 in detail. FIG. 8 is a partial perspective view of an embodiment in which Fresnel lens sheets are combined. (1)...Transmissive screen (2)...Projection surface (3)...Observation surface (2
1), (33), (35), (36)...Lens body (31)...Elongated groove (32)...Light-absorbing filament (P)...・・・Projector compilation 2 (2) 5th edition, 7th edition, Qin a diagram

Claims (1)

[Scope of Claims] 1. A transmission type frame 1 which is on the same side as the projection surface and the observation surface, and at least 10,000 surfaces of the projection surface and the observation surface are formed to have a lens function, and In a transmission screen configured such that light projected onto a projection surface defines a large number of bright striped portions on the viewing surface through which light passes and dark striped portions through which light does not pass, the dark striped portion of the viewing surface 1. A transmission screen characterized in that long and narrow grooves are formed in the substrate, and light-absorbing filamentous materials coated with an adhesive are adhesively arranged in the long and narrow grooves. 2. The transmission screen according to claim 1, wherein a lenticular lens body is provided on the projection surface to have a lens effect. (5) The transmission screen according to claim 1, wherein a lenticular lens body is provided on the observation surface to have a lens effect. 4. The transmission screen according to claim 3, characterized in that total reflection surfaces are provided on both inclined surfaces of each lens unit constituting the lenticular lens body. 5. A transmission screen according to claim 1, 5, or 4, characterized in that a Fresnel lens is provided on the projection surface. 6. A transmission screen according to any one of claims 1 to 85, characterized in that a diffusing agent is added to the base material constituting the screen. 2. A transmission screen according to claims 1 to 6, characterized in that a light-absorbing colorant is added to the base material constituting the screen.