JPS6079343A - Transmission type screen - Google Patents

Abstract

PURPOSE:To expand the angle of a field of view by providing a substance layer having a swaller refractive index than that of a base material for constituting a screen on the outside surface of a groove forming adjacently a total reflecting surface provided on the inclined surface of both sides of a lens unit constituting a lenticular lens and also waking adhere and fixing a light absorptive threaded substance to the inside of the groove. CONSTITUTION:A lenticular lens to a vertical direction is formed on the observation surface 3 of a screen. That is to say, for the lens unit 31 of this lenticular lens, a total reflecting surface 31a is provided on the inclined surface of both sides, and light which is made incident on this part is reflected totally one, and thereafter, emitted extending over a wide angle from the lens surface 31b of the top part. A substance layer 33 having a swaller refractive index than that of a base material is provided on the outside surface of the total reflecting surface 31a to exert no influence on the total reflecting action of the total reflecting surface 31a, even if an adhesive agent 35 for waking adhere a light absorptive threaded substance 34 is stuck. The threaded substance 34 is not specifically limited, as long as it has light absorbing ability and prescribed strength.

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 absorption stripes in order to provide a wide viewing angle and good image contrast.

Various types of transmissive screens have been proposed for use in video screens, etc. of videoglogeography televisions, and some of them have already been put into practical use.

Video glogeation television projects a large image onto its video screen, and is primarily used for the purpose of allowing a large number of viewers to view it 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 approximately parallel to each other. It refracts and focuses the light, then diffuses the light into a specific angular range and emits it from the viewing surface. In this way, the lenticular screen is made up of a large number of long and thin lenses arranged in a row, so the front surface of the lenticular screen has two parts: one is a bright part through which the emitted light passes, and the other is a long and thin part through which the light does not pass. 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 transmissive 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 a lot of 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:

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 Dechiru.

In a dark room with no outside light, increasing the BMAX/BMIN ratio will improve the contrast, but in a bright room affected by outside light, the reflected brightness of the outside light (B11 B2) must be taken into consideration.

In other words, in order to increase the contrast of the image on the video projection screen itself, the reflected brightness of external light on both sides (
B1. B+)K should be suppressed as much as possible. In other words, the video projection screen is made to have an external light absorption function by increasing the amount of external light that passes into the inside of the video projection screen. , the surface of the screen is provided with a light absorbing portion' (il-).

As such a screen, for example,
No. 6693 is known. This special public service 1972-46
Publication No. 693 proposes increasing the contrast by providing a light-shielding stripe portion on the opposite side of a transmissive video projection screen in which a lens gate consisting of a large number of cylindrical lenses is provided on one side, in a portion through which no light passes. There is. Although providing light-shielding stripes in this manner is effective for increasing the contrast of images, when a general lenticule is used, the viewing angle is not necessarily sufficient. The video projection screen of the above-mentioned Japanese Patent Publication No. 52-46695 is provided with a photoresist film on the opposite side of the lenticular screen, and this film is exposed, developed, and dried. It is constructed by forming a photoresist film no-strap pattern in which the photoresist film is left only in areas through which light does not pass, and then attaching oil-based ink gold offset printing or the like to this stripe pattern to form a light-shielding area.

However, printing all the oil-based one ink on the stripe pattern as described above requires highly advanced 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. In addition, the photoresist film must go through a process of exposure, development, and drying, and work in a dark room is required for manufacturing on the video projection screen, which complicates the manufacturing process and also causes poor adhesion of the photoresist film. ,
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 is conceivable, but uneven printing tends to occur and, as mentioned above, it is difficult to paint with a narrow and uniform width.

Therefore, as a result of studies to increase the viewing angle in the horizontal direction, the applicant provided a vertical lenticular lens with a total reflection surface on the viewing surface, and reflected a portion of the light incident on the screen from the light source. He proposed widening the viewing angle by totally reflecting the light on a reflective surface and emitting it to the observation side (Japanese Patent Application No. 56-51194, Japanese Patent Application No. 56-90544).
No. 56-91896, and the uniquely shaped lenticule, the adjacent total reflection surface has a groove shape,
The present inventor has already proposed that a transmissive screen with good contrast can be obtained by storing and arranging a light-absorbing filament using this dark stripe area through which light does not pass (particularly (Gan Sho 57-254409). However, when using an adhesive as a method of fixing the light-absorbing filament, there was a concern that the adhesive would adhere to the total reflection surface, causing light transmission and absorption on the total reflection surface. was completed after careful consideration so that the function of the total reflection surface would not be degraded even if the light-absorbing filament was fixed with an adhesive.

That is, the gist of the present invention is a transmission type screen in which vertical lenticular lenses are formed on the observation surface, and the lens units constituting the lenticular lenses have total reflection surfaces on both inclined surfaces. In addition, a groove is formed in the adjacent total reflection surface, and a material layer having a refractive index lower than that of the base material forming the screen #II is provided on the outer surface of the total reflection surface, and a material layer is provided in the groove. The transparent screen is characterized by having a light-absorbing yarn attached to it with adhesive.

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 formed on the observation surface of the transmission screen described above can be easily formed at the same time as the total reflection surface.

It is also effective to add a diffusing agent to the base material constituting the entire transmission chamber screen of the present invention to completely compensate for the vertical diffusivity of the screen. The diffusing agent at this time is 5i02.
At203. At(OH)3. BaSO4゜Ti
Examples include O2, Ca003, and the like. Similarly, when a light-absorbing colorant such as carbon black or aniline black is added to this base material in combination with a diffusing agent or alone, the brightness of the screen can be adjusted. However, if a large amount of this light-absorbing colorant is added, the transmittance of the screen will decrease, so it is desirable to add about 10 to 20 ppm so that the total light transmittance does not become less than 60.

The invention will be explained in more detail below in the form of an exemplary embodiment and with reference to the accompanying drawings, in which: FIG.

FIG. 1 is a schematic illustration of a video glogejection device ta, in which a transmission screen (1) of the present invention has projection light projected from a video projector (P) onto a projection surface (2). In this example, the projection surface (2) is equipped with a Fresnel lens (2 lenses), which refracts the light incident on the projection surface (2) into parallel light and focuses it on a predetermined spot on the viewing side. Because of this, it is useful for maintaining the brightness especially around the screen and making the screen uniform in brightness, but of course this may be omitted.

On the other hand, a vertical lenticular lens shown in FIGS. 2 and 3 is formed on the viewing surface (3) of the transmission screen of the present invention. In other words, the lens unit (3) of this lenticular lens is provided with a total reflection surface (31a) on both inclined surfaces, and the light incident on this part is once totally reflected, and then reflected by the top lens surface (31b) at a wide angle. For example, the base material has a refractive index of 1,
When a lenticular lens as shown in Figure 3 is made using 492 acrylic resin, the angle (α) of the total reflection surface is approximately 69.
′ is necessary, but the rays incident parallel to this total reflection surface are totally reflected by the total reflection surface (31a), and are emitted from the lens surface (311) at the top of the lens unit (31). Since some of the light is emitted at a large angle, a wide viewing angle can be obtained as a whole. Since a groove (32) is formed by the adjacent total reflection surfaces (31a), the groove (32) portion constitutes a dark stripe through which no light passes. The transmissive screen shown in Fig. 4 is not substantially different from these, only the shape of the lens unit (lens surface (31b') at the top of the lens is different), and grooves (32) are similarly formed. ing.

However, if a substance with a higher refractive index than the base material or a light-absorbing substance adheres to the outer surface of this total reflection surface (31a), the light that should be totally reflected will be transmitted and absorbed here. Become. Therefore, in the present invention, the total reflection surface (31a
) on the outer surface of the material layer (33)' which has a lower refractive index than the base material.
Even if the adhesive (35) for adhering the light-absorbing filament (34) is attached, the total reflection surface (31a)
It is designed so as not to have any effect on the total reflection effect of the

For example, using acrylic resin with a refractive index of 1.492 as the base material, α is 755° with the size (between units) shown in Figure 3.
In the case of the lenticular, the refractive index of the material layer (33) is 1
．． 46 or less, but examples of substances with such a refractive index include, for example, the silicone paint Ki Evotec 394 (manufactured by Epoxy Technology Co., Ltd., refractive index 1,
394) Yafutsuso paints are mentioned. Among these, as a fluorine-based paint, 2.2.3.3.3-
Pentafluoropropyl methacrylate (refraction $1.4
15) i A solution dissolved in methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, or the like is used.

Also, as the adhesive (35), a wire, the light-absorbing filament (3)
A material that can bond the substance layer [33] with a low refractive index to the material layer [33] is used.
When the above-mentioned silicone paint is used as 3), an epoxy adhesive or N Evotech VA-67/also manufactured by Epoxy Technology Co., Ltd. is preferable. Furthermore, when a fluorine-based paint is used, a solvent-based adhesive such as vinyl acetate-based, acrylic-based, or urethane-based adhesive can be used, and in some cases, a hot-melt adhesive can also be used.

Note that the thread-like material (34) used in the present invention is not particularly limited as long as it has light absorption ability and a predetermined strength. For example, spun yarns or filament yarns made of natural fibers or synthetic fibers that are necessarily dyed in dark colors are common, but instead of these fiber yarns, metal fiber yarns such as aluminum or ultrafine metal fibers such as piano wire are used. is available.

FIGS. 5(A) to 5(D) show the process of processing the viewing surface (3) of the transmission screen of the present invention.
The lens surface (31b) of the lenticular lens unit (31)
), water-soluble paints such as 1 Berorin (manufactured by Musashi Paint Co., Ltd.) or ``Chemipack'' (manufactured by Tamagata Kako Co., Ltd.), or 'R-568' (made by Seitama-Advance Co., Ltd.) as shown in the same figure (A). A mask layer (36) is formed using one color of alkali-soluble resist (manufactured by Kawasaki Co., Ltd.).Next, a paint with a low refractive index is applied to the entire surface of the lenticular lens to form a material layer (33). ), a light-absorbing filament (3
4) Glue with 'e adhesive (65) (same figure (C)
)). Finally, add the material to that part of the mask layer (36). (33) is removed to form an observation surface as shown in (D) of the same figure.

The present invention is constructed as described above, and includes a total reflection surface (31a) which becomes the original non-transparent stripe portion of the lenticular lens provided on the observation surface (3), and a groove (32) formed thereby. Light-absorbing filament C54)
Since the light-shielding stripe part can be provided in a precise position, the filamentous material (34) is stable and the viewing angle can be widened. Therefore, it is possible to provide a transparent screen.

Although the present invention' (I-1 embodiment) has been described in detail above, the present invention is not limited to the above embodiment, and can be variously modified within the scope of the claims.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view schematically showing a video projector device using a transmissive screen of the present invention, and Fig. 2 is a perspective view of a video projector device using a transmissive screen according to an embodiment of the present invention. FIG. 3 is an enlarged view of the observation surface in FIG. 2; FIG. 4 is a partial cross-sectional view of another embodiment of the transparent pot screen; FIGS. 5(A) to 5(D) are diagrams schematically illustrating the processing steps of the viewing surface when manufacturing the transmission screen of the present invention. (1)...Transmissive screen, (2)...Projection surface, (3)...Observation surface (2
1)... Fresnel lens, (61)... Lens unit, (31a)...
Total reflection surface (32)...Groove (33)...Low refractive index material layer (34)...Light-absorbing filament, (35)...Adhesive spot 2 Figure 1 Breast 3 Figure 1 Tail 5 Figure

Claims (1)

[Scope of Claims] 1. A transmission type screen in which vertical lenticular lenses are formed on the viewing surface, and the lenticular lenses are composed of five lens units each having a total reflection surface on each inclined surface. , furthermore, a groove is formed in an adjacent portion of the total reflection surface, and a material layer having a refractive index lower than that of the base material constituting the entire screen is provided on the outer surface of the total reflection surface,
A transmission screen characterized in that a light-absorbing filamentous material is adhesively fixed in the groove. λ The transmission screen according to claim 1, characterized in that a Fresnel lens is provided on the projection surface. (5) A diffusing agent is added to the base material constituting the broadcasting system according to claim 1 or 2. A transparent screen characterized by: 4. A transmission screen according to claims 1 to 3, characterized in that a light-absorbing colorant is added to the base material constituting the screen.