JPH0366649B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transmission screen that generates an image by receiving image light projected from a projection device.

(Prior art) Screens are classified into reflective screens and transmissive screens.Reflective screens are used to observe the projected image projected from a projection device and reflected there.Therefore, the projection device and the viewer are on the same side of the screen. However, the transparent screen is used to observe the transmitted image of the projected image focused on the screen surface, and therefore the viewer views it from the opposite side of the projection device, also known as the rear screen. Also called a projection screen.

This transmission screen is made of a plate or sheet made of a material with good light transmission, and its surface is roughened (textured).
It is constructed by processing it so that light is diffused non-directionally by coating it with a suitable diffusion layer.

However, a transparent screen with this structure,
Because the light is not diffused sufficiently, a hot spot (glare) occurs in the center when used, and the brightness in the center is significantly higher than in the four corners, resulting in an extreme difference in brightness and darkness in the image even when viewed from the front. , especially when observing diagonally from the front.
Parts farther away from the location will be darker than parts closer to the location, making it nearly impossible to observe the image. To explain this in detail, Figure 1 shows a conventional transparent screen A.
The transparent screen A is set between a projection device 1 and an observer 2. This transmission screen A is made of an acrylic plate or the like with good light transmittance, and one side 3a of the screen plate 3 is treated with a non-directional light diffusing film by forming ultrafine uneven embossing, etc. It consists of a black mesh 4 stretched on the viewer 2 side of the screen plate 3 to improve contrast.
FIG. 2 is a perspective view of the transparent screen A.
In addition, in this FIG. 2, only a part of the black mesh 4 is drawn.

FIG. 3 is for explaining the optical characteristics of the screen plate 3 of this transmission screen A. One side 3a, which is the front side, is matted by embossing with extremely fine irregularities as shown in FIG. 3a. It has a directional light diffusing film surface. FIG. 3b shows a cross section.

When light is projected from the projection device 1 onto such a screen plate 3, the light is scattered only by the light diffusion film surface on one side 3a, and the unevenness of this light diffusion film surface is extremely minute. , the light diffusion characteristics are poor, and as shown in FIG. 3c, a hot spot a is formed in the center, and the four corners are dark.

FIG. 8 shows the brightness characteristics in a state where these hot spots appear. In FIG. 8, the left side shows the brightness at the viewing angle from the center in the horizontal direction, and the right side shows the brightness at the viewing angle from the center in the vertical direction. As shown in this figure, the hot spot has a circular shape with the same steep curve in both the horizontal and vertical directions.

Therefore, as shown in JP-A-58-122527, a surface with a plurality of vertically curved lenses and a surface with a plurality of horizontally curved lenses are provided, and each surface directs light in the vertical and horizontal directions. Transparent screens have been proposed that diffuse light to prevent the formation of light spots.

(Problem to be solved by the invention) However, with this structure, although the light is diffused in the direction of the curved surface of the curved lens on each surface and light spots are reduced, the vertical and horizontal curved lenses are precisely aligned. Therefore, the problem is that the light in the center is only diffused horizontally and vertically, and the corners are darker than the center.

Furthermore, since the black screen 4 for improving contrast shown in FIG. 1 is placed on the viewer's side of the screen, there is a problem that the screen becomes black and crushed when the screen is observed from an oblique direction.

Furthermore, if the screen plate 3 in FIG. 1 is thin, it is difficult to attach the black mesh 4 to it closely.

An object of the present invention is to provide a transmission screen that solves all of the above-mentioned problems.

(Means for Solving the Problems) For this purpose, the transmission screen of the present invention includes a non-directional light diffusion film and a plurality of semicylindrical lenses having different radii of curvature and lengths in the longitudinal direction so as to concentrate and diffuse light primarily in the horizontal direction. The first wrench killer has an embossed surface where the lenses are mixed almost in parallel, and the second wrench has a plurality of semicylindrical lenses with different radii of curvature and lengths in the longitudinal direction mixed almost in parallel to concentrate and diffuse light mainly in the vertical direction. The radius of curvature of the semi-cylindrical lens of the first Wrench Killer emboss was compared with that of the second Wrench Killer emboss on a transparent screen in which the surfaces on which the killer emboss was applied were overlapped and the surface facing the viewer was covered with a black net. and make it smaller.
In addition, the film and each of the above surfaces are formed into separate sheets with good light transmittance, and each sheet is stacked and pasted on the convex side of a transparent plate curved in the vertical direction so that the viewer side is the convex side. , and the mesh of the black mesh is longer in the horizontal direction than in the vertical direction.

(Example) Examples of the present invention will be described below. First, the technology behind the embodiment will be explained.

FIG. 4 shows one side 3a of the screen plate 3 mentioned above.
In addition to the light diffusing film described above, the multi-focus lenticular emboss is mainly rotated in the vertical direction. This multi-focus wrench killer emboss is formed by mixing several types of semi-cylindrical lenses with different radii of curvature and lengths in the longitudinal direction in parallel in the horizontal direction. As a result, when light is projected, the light is concentrated and diffused in the horizontal direction as shown in FIG.

In a normal Wrench Killer Emboss, the kamaboko lenses with the same radius of curvature are arranged precisely in parallel, so if light is projected onto them, the light will be diffused in the direction perpendicular to the curved surface of the kamaboko lens, that is, in the longitudinal direction of the kamaboko lens. However, in the present invention, as shown in Fig. 4b, semicylindrical lenses with various curvature radii are formed mainly in the vertical direction with various lengths as shown in Fig. 4a. Therefore, the light is diffused to some extent not only in the horizontal direction but also in the vertical direction, resulting in a high-intensity hot line b having a width in the vertical direction.

FIG. 8 shows this characteristic. In the horizontal direction, a certain degree of brightness gain can be obtained even from an angle quite far from the center, but in the vertical direction, little brightness gain can be obtained even at an angle quite close to the center. Note that the angle is 0
This is because the light from that area is concentrated and diffused in the surrounding area, especially in the horizontal direction, rather than in front.

In FIG. 5, as described above, one side 3a is provided with a non-directional light diffusing film and a multi-focus wrench killer embossing is applied mainly in the vertical direction, and the other side 3b is provided with
Multi-focus wrenchkiller embossing is applied mainly in the horizontal direction. Therefore, due to the concentration and diffusion of light in the vertical direction by the multi-focus lenticular embossing on the other surface 3b, the high brightness hot line b that appears in FIG. 3 is expanded in the vertical direction, and the screen plate 3 is becomes high brightness.

In addition, in this multi-focus wrench killer emboss, the width of the semi-cylindrical lens is wider and the radius of curvature is larger than that of the multi-focus wrench killer emboss applied on one side 3a. For example, an embossed kamaboko lens on one side 3a with a width of 1
Assuming 9 to 11 embossments per mm, the number of embossing on the other side 3b is 4 to 6 per 1 mm of width. Therefore, the spread of light in the vertical direction on the other surface 3b is due to the above-mentioned difference in width and curvature of the semicylindrical lens.
It is smaller than the spread on one side 3a.

This was done for the following reasons. In other words, the spread of light in the vertical direction of the transmission screen A is determined by the radiation angle ±
It is sufficient to cover a width of about 15 degrees, but considering the case where multiple observers are lined up side by side, it is necessary to cover a width of about ±35 degrees from the radiation angle.

FIG. 8 shows this characteristic. In the horizontal direction, the gain decreases with a curve having a shape almost similar to the characteristic curve of , but in the vertical direction, the gain improves over a wider angle. Therefore, differences in screen gain due to differences in viewing angles of observers are reduced.

FIG. 6 is an explanatory diagram of the black mesh 4. Transmissive screens have the advantage that they can be used in bright places compared to reflective screens, but when light rays from the front of the screen hit the screen, the contrast of the projected image transmitted from the back is impaired. Therefore, in order to prevent this, the black netting 4 is pasted on the side facing the observer.

The black net 4 is made of a black synthetic resin or a thin metal wire coated with black (preferably a fine wire whose surface has been treated with a matte finish). This black net 4 is the seventh
As shown in the figure, illumination light source B from the front ceiling direction
The thin wire 4a acts as a hood for the light reflected from the floor 5 by the light source B (the reflected light source is indicated by B'), and the shadow due to the diameter of the thin wire 4a (the light by the light source B is x, the reflected light source B' is )
is caused on the screen plate 3, and the reflection on the surface of the screen plate is reduced by the area of the shadow. Therefore, contrast can be improved.

Also, as shown in Figure 6a, if the horizontal length of the black mesh 4 is longer than the vertical length (for example, 1:2), when observed from diagonally horizontally in front, the vertical It is also possible to alleviate the problem that the directional mesh appears to be collapsed and the image becomes difficult to see.

Figure 8 shows the gain when this black mesh 4 is pasted, and compared to the characteristics of , the gain is reduced by the amount of light loss in the black mesh 4, but the contrast improvement effect is greater. much larger. .

From the above, basically, a transmission screen is formed by applying a multi-focus lens killer embossing with a non-directional light diffusing film on one side 3a of the screen plate 3 and a multi-focus lens killer mainly in the vertical direction with a small width and a small radius of curvature, and on the other side 3b. If a multi-focus lens killer embossing with a wide kamaboko lens and a large radius of curvature is applied mainly in the horizontal direction, and a black mesh 4 is pasted on the viewer side of the screen plate 3, the The image projected from the projection device 1 appears on the diffusion film of the screen whose entire surface is in a state of high brightness due to the diffusion film and each multi-focus wrench killer emboss.

However, in the above explanation, one screen board 3
A non-directional light diffusing film and a multi-focus wrench killer emboss are provided on the screen, but from the viewpoint of manufacturing and practical use, it is difficult to use multiple screen plates, for example, three, and one of them is a non-directional light diffusing film plate and the other. It is preferable that one of the sheets is, for example, a transparent plate with multi-focus wrench killer embossing applied in the horizontal direction on one side, and the remaining one is made, for example, a transparent plate with multi-focus wrench killer embossing applied in the vertical direction on one side. In this case, if the diffusion membrane plate or transparent plate is a thin sheet, it is difficult to stick them tightly together, but this can be solved as shown in FIG. 9.

In Fig. 9, reference numeral 10 denotes a transparent plate with a wall thickness of about 1 to 5 mm that has a convex curved surface only in the vertical direction, and a sheet 11 on the convex side of which is embossed with multi-focus wrenchkiller mainly in the horizontal direction. A sheet 12 with multi-focus wrench killer embossed in the vertical direction and a non-directional diffusion film sheet 13 are placed in this order, and a black net 14 is placed on the outside of the sheet 13. In this way, each of the sheets 11 to 13 and the black mesh 14 can be attached to the transparent plate 1.
Since it is in close contact with the convex side of the screen, there will be no unevenness in parts, and even when used for large screens, the screen will not sway due to wind or the like.

In addition, since a transmission screen can be configured with multiple sheets in this way, if you prepare multiple sheets with different aggregated diffusion rates in one direction, you can adjust the screen size of a normal TV receiver (aspect ratio 3:4) and height. Controls the rate at which light is spread in the horizontal and vertical directions for applications such as TV receiver screen size (3:5 aspect ratio) or movie size (3:8, 3:10 aspect ratio). , can be easily accommodated.

Moreover, when it is made into a sheet, it is easy to join the sheets together to make a large screen.

(Effects of the Invention) As described above, according to the present invention, the radius of curvature of the kamaboko lens of the first wrench killer emboss is made smaller than that of the second wrench killer emboss. The entire surface can be accurately and almost evenly brightened.

In addition, the non-directional light diffusing film, the first lenticiller embossed surface, and the second lenticillary embossed surface are each formed into separate light-transmitting sheets, which are curved in the vertical direction. Since the convex side of the transparent plate facing the viewer is stacked on top of the transparent plate, even if the transparent plate and each sheet are thin, they can be attached closely to each other, and the convex side is oriented vertically instead of horizontally. Therefore, even if the viewer is located at the left or right edge of the screen, the viewing of the entire screen will not be adversely affected.

Furthermore, since the mesh of the black mesh is made longer in the horizontal direction than in the vertical direction, the screen will not be crushed by the mesh even when observed from the left and right edges of the screen.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the use of a conventional transparent screen.
FIG. 2 is a perspective view of the transmission screen in FIG. 1, FIG. 3a is an explanatory diagram of a conventional transmission screen in which a non-directional light diffusion film is applied on one side of the screen plate constituting the transmission screen, and b is a cross-sectional view. Figure 4 (c) is an explanatory diagram of the case where light is projected from the back, Figure 4 (a) is an explanatory diagram of one side of the screen plate with a non-directional light diffusion film and multi-focus wrenchkiller embossed mainly in the vertical direction, and (b) is an enlarged partial cross section. Figure 5c is an explanatory diagram when light is projected from the back, and Figure 5a is a screen plate with a non-directional light diffusion film on one side and a multi-focus lenticular embossed mainly in the vertical direction, and mainly in the horizontal direction on the other side. An explanatory view of the other side with multi-focus wrenchkiller embossed on the side, b is an enlarged partial sectional view, c is an explanatory view when light is projected from the back side, Fig. 6a is a partial view of the black mesh, b
7 is a diagram illustrating the function of the black mesh, FIG. 8 is a luminance characteristic diagram, and FIG. 9 is a partial sectional view of a transparent screen according to an embodiment of the present invention. A... Screen, 1... Projection device, 2... Observer, 3... Screen board, 4... Black net, 10...
...Transparent plate, 11... Sheet with multi-focus wrench killer embossing mainly in the horizontal direction,
12... Sheet with multi-focus lenticular embossing mainly in the vertical direction, 13... Non-directional light diffusing film sheet.

Claims (1)

[Claims] 1. A first wrench killer emboss in which a non-directional light diffusing film and a plurality of semicylindrical lenses having different radii of curvature and lengths in the longitudinal direction coexist almost in parallel so as to concentrate and diffuse light primarily in the horizontal direction. The embossed surface and the second lenticiller embossed surface, in which multiple kamaboko lenses with different radii of curvature and length in the longitudinal direction coexist in almost parallel to concentrate and diffuse light mainly in the vertical direction, are overlapped and observed. In a transparent screen whose surface on the user side is covered with a black mesh, the radius of curvature of the semicylindrical lens of the first Wrench Killer emboss is made smaller than that of the second Wrench Killer emboss, and the film and each of the surfaces are formed into separate sheets with good light transmittance, and each of the sheets is stacked and pasted on the convex side of a transparent plate that is vertically curved so that the viewer side is convex, and the mesh of the black mesh is A transparent screen characterized by being longer in the horizontal direction than in the vertical direction.