JP3182599B2 - Video projection screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen for projecting and displaying an image with a projector such as a projector or a liquid crystal projector.

[0002]

2. Description of the Related Art Recently, a large image projection screen is provided at a place where young people gather and a variety of commercial or service images are projected and displayed by a projector such as a projector or a liquid crystal projector. Such a screen is often limited to a narrow range in view point (viewing position) due to the installation location and the like.

[0003]

However, in the conventional screen, the visibility of the projected image is poor because the light source of the projector is not so strong. In particular, when the screen is installed in a bright place such as outdoors. However, there is a problem that the image is extremely difficult to see. Such a problem,
Using a high-power projector light source solves this a bit, but has limitations.

[0004] The present invention has been made in view of the above problems, and in a screen in which the viewpoint is limited to a narrow range,
It is intended to improve the contrast of the image projected on the surface and to significantly improve the visibility.

[0005]

In order to achieve the above object, a video projection screen according to the present invention has a light-shielding grid assembled by assembling a large number of light-shielding plates vertically and horizontally on a front surface of a screen having a narrow viewpoint range. At the same time, at least the horizontal light shields, preferably the vertical and horizontal light shields, are slightly inclined in a direction that passes through the specific convergence point range between the viewpoint range and the projector when virtually extended forward. It is characterized by:

More preferably, the above-mentioned screen is surrounded by a frame, and a light-shielding grid arranged on the front surface of the screen is attached to the inside of the frame so that the screen can be inclined back and forth within a predetermined angle range with respect to the screen. Things.

[0007]

When a light-shielding grid assembled by intersecting a large number of light-shielding plates vertically and horizontally like the image projection screen of the present invention is arranged on the front surface of the screen, the left, right, upper and lower sides are obliquely viewed from the front. Since the incidence of light on the screen is blocked, the contrast of the image projected and displayed on the screen is improved.

In this case, if the vertical and horizontal light shielding plates of the light shielding grid are at right angles (perpendicular) to the screen, when the screen is viewed from the viewpoint range, the vertical and horizontal light shielding plates in front of the viewpoint can only see the thickness. However, as the vertical and horizontal light blocking plates are separated from the position directly in front of the viewpoint in the left, right, up, and down directions, the board surface becomes larger in addition to the plate thickness, so that the visibility inhibition ratio of the screen image by the light blocking plates increases. For similar reasons,
As the vertical and horizontal light shielding plates move away from the position directly in front of the projector in the left, right, up, and down directions, the inhibition ratio of the projected light rays from the projector increases. However, like the image projection screen of the present invention,
If at least each light-shielding plate in the horizontal direction of the light-shielding grid is slightly extended in a direction passing through a specific convergence point range between the viewpoint range and the projector when virtually extending forward, the position in front of the viewpoint is Since the visible area of the plate surface is reduced even with a light shield plate that is separated from the top and bottom of the screen, the ratio of obstruction of viewing the screen image by the horizontal light shield decreases, and for the same reason, the ratio of inhibition of the projected light by the horizontal light shield also decreases. descend. In particular, when each of the vertical and horizontal light shielding plates is slightly inclined in the direction of the above-mentioned convergence point range, the inhibition ratio of the screen image visual recognition and the projection light inhibition ratio by the vertical light shielding plates also decreases. The closer the convergence point range and the viewpoint range are, the smaller the viewing inhibition ratio of the screen image is, and the closer the convergence point range and the projector are, the smaller the inhibition ratio of the projected light is.

As described above, in the image projection screen of the present invention, the contrast of the image projected and displayed on the screen is improved by the shading grid, and the obstruction ratio of the screen image and the obstruction ratio of the projected light beam by the shading plate are reduced. Because of its small size, the image is clear and the visibility is extremely good even when the surroundings are bright and the light source of the projector is not strong.

[0010] Further, the screen is surrounded by a frame, and the above-mentioned light-shielding grid arranged in front of the screen is attached to the inside of the frame so that the screen can be tilted back and forth within a predetermined angle range with respect to the screen. For example, when the convergence point range moves due to a change in the positional relationship between the screen and the projector due to use conditions and installation conditions, simply adjusting the inclination angle of the light-shielding grid and moving the vertical and horizontal light-shielding plates after the movement It can be directed to the direction of the convergence point, so that good visibility can be maintained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of an image projection screen according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the screen, and FIG. 3 shows the relationship between the screen, a projector, a viewpoint, and a convergence point. FIG.

As shown in FIG. 1, this video projection screen comprises a screen 1 and a light-shielding grid 2 arranged on the front surface thereof.

As the screen 1, for example, a milky white resin plate or a screen in which a milky white cloth, a thin resin plate, or the like is adhered to a base material is used. Any material and structure may be used.

The light-shielding grid 2 is formed by crossing a large number of vertical and horizontal light-shielding plates 2a and 2b having cuts formed at equal intervals at a right angle, and meshing the cuts to form a grid. Such a light-shielding grid 2 is advantageous in that the material processing and assembly are simple, and that the strength can be obtained even with a very thin material. A resin plate, a metal plate, or the like is used as the vertical and horizontal light-shielding plates 2a, 2b, and as described later, it is desirable to use an iron plate or the like so that the strength can be obtained with a thickness as thin as possible. The light-shielding plates 2a and 2b are preferably made of a non-reflective surface by applying a black matte coating or a surface treatment to the plate surface so that light is not reflected.

The image projection screen of the present invention has a side of 50.
It is most suitable for a large size of 0 mm or more. In this case, the arrangement interval A of the vertical light shielding plates 2a and the arrangement interval B of the horizontal light shielding plates 2b are set to about 30 to 200 mm, respectively, in terms of strength and cost. Is preferred. Vertical and horizontal light shield 2
In consideration of the fact that the output of the light source of the projector 3 is not so strong, the front and rear widths (depths) of a and 2b are at least twice as large as the above-mentioned arrangement intervals A and B, and practically about 3 to 5 times. It is desirable to set. If the depths of the light shielding plates 2a and 2b are at this level, it is possible to sufficiently shield external light from entering the screen 1 from each of the upper, lower, left, and right oblique fronts.
The contrast of the image projected on the screen can be reliably improved.

The arrangement intervals A and B do not need to be the same. For example, in a place where direct sunlight is likely to receive from above, the arrangement interval of the light shielding plates is set to A> B, so that the light shielding effect is more effective. What is necessary is just to set so that it may be exhibited. Also,
The front-back width (depth) of the light-shielding plate does not need to be the same. For example, as shown in FIG.
And the front and rear widths of the horizontal light shielding plates 2b at both the upper and lower ends are set to be larger than the front and rear widths of the vertical and horizontal light shielding plates on the inner side, or in a place where direct sunlight is likely to receive from above, the horizontal light shielding plates 2b The front-rear width may be made larger than the front-rear width of the vertical light shielding plate 2a to enhance the light shielding effect. Further, when the viewpoint range (position) is slightly widened to the left and right, the width of the vertical light shielding plate 2a is set to be small, and the horizontal light shielding plate 3b is set to be slightly inclined as described later. I just need.

The thickness of the vertical and horizontal light shielding plates 2a and 2b is desirably as thin as possible so as not to block an image projected on the screen 1. At least the intervals A,
It is desired that the thickness be 1/20 or less of B, preferably 1/100 or less. Specifically, a thickness of about 0.3 to 1.2 mm is appropriate, and in the embodiment, an iron plate having a thickness of 0.5 mm is used.

As shown in FIG. 2, the light shielding grid 2
The feature is that the vertical and horizontal light shielding plates 2a and 2b are not perpendicular (perpendicular) to the screen 1 but are slightly inclined. That is, the vertical and horizontal light shielding plates 2a and 2b
When it is virtually extended forward, it is slightly inclined in a direction passing through a convergence point P in a specific range between the viewpoint E and the projector M in a narrow range.

It is assumed that the vertical and horizontal light shielding plates 2a, 2
Assuming that b is a right angle (perpendicular) to the screen 1, when the screen 1 is viewed from the viewpoint E, the vertical and horizontal light shielding plates in front of the viewpoint E can only see the thickness, but only in the thickness direction. The light-shielding plates 2a and 2b separated from the position in the left, right, up, and down directions can see the plate surface in addition to the plate thickness. And, as the horizontal and vertical light shielding plates 2a and 2b are farther away from the position in front of the viewpoint, left, right, up and down, the visible area of the plate surface increases.
The visibility inhibition ratio of the screen image by the light shielding plates 2a and 2b increases. For the same reason, the vertical and horizontal light shielding plates 2a,
As the position of 2b moves right and left and up and down from the position in front of the projector M, the inhibition ratio of the projection light from the projector M also increases.

However, when the vertical and horizontal light shielding plates 2a and 2b are virtually extended forward like the light shielding grid 2, the viewpoint E
Is slightly inclined in the direction passing through the convergence point P between the light source and the projector M, even if the light shielding plates 2a and 2b are separated from the position in front of the viewpoint E by right and left and up and down, the visible area of the plate surface decreases. In addition, the visibility inhibition ratio of the screen image by the light shielding plate decreases, and the inhibition ratio of the projected light rays by the light shielding plates 2a and 2b also decreases for the same reason. The closer the convergence point P and the viewpoint E are, the smaller the visual inhibition ratio of the screen image is, and the closer the convergence point E is to the projector M, the smaller the inhibition ratio of the projected light is.

The position of the convergence point P can be adjusted to the position of the viewpoint E or the projector M. However, if the convergence point P is adjusted to the viewpoint E, only the thickness of the light shielding plates 2a and 2b can be seen. While the screen viewing inhibition ratio is minimal,
The area where the projection light is blocked by the plate surfaces of the light shielding plates 2a and 2b is increased, and the inhibition ratio of the projection light is maximized, so that the sharpness of the image is considerably reduced. For the same reason, the convergence point P
Is adjusted to the position of the projector M, the inhibition ratio of the projected light beam is minimized, but the visual inhibition ratio of the screen image is maximized, so that the visibility of the image is considerably reduced. In contrast,
If the convergence point P is set within a certain range between the viewpoint E and the projector M, both the visibility inhibition ratio of the screen image and the inhibition ratio of the projected light beam decrease, so that both the sharpness and the visibility of the image are reduced. Moderately maintained, making screen images easier to see.

In practice, as shown in FIG. 3, the projector M is often installed on the ground. In this case, the most preferable position of the convergence point P is set at the upper end of the screen 1 from the projector M and the viewpoint E, respectively. The line L3 bisecting the included angle α1 sandwiched by the lines L1 and L2 and the included angle α2 sandwiched by the lines L4 and L5 extending from the projector M and the viewpoint E to the lower end of the screen 1, respectively. This is a point that intersects with the line L6, and is located on the left-right symmetry plane of the screen 1.

When the convergence point P is set as described above and the vertical and horizontal light shielding plates 2a and 2b of the light shielding grid 2 are slightly inclined toward the convergence point P, either the included angle α1 or the included angle α2 is obtained. When the larger one is 20 ° or less, the sharpness and visibility of the screen image are effectively improved, and particularly when it is 10 ° or less, it is extremely effectively improved.

In the above embodiment, the vertical and horizontal light shielding plates 2a and 2b of the light shielding grid 2 are slightly inclined toward the convergence point P, but the range of the viewpoint E is slightly widened in the horizontal direction. Therefore, it is not always necessary to incline the vertical light shielding plate 2a, and only the horizontal light shielding plate 2b is inclined to reduce the inhibition ratio of the screen image and the inhibition ratio of the projected light beam by the horizontal shielding plate 2b. That is enough for practical use.

FIG. 4 is a perspective view showing an image projection screen according to another embodiment of the present invention, FIG. 5 is a longitudinal sectional view of the screen, and FIGS. 6 and 7 are partially enlarged sectional views of the screen.

This image projection screen is a screen 1
Is surrounded by a frame 3, and a light-shielding grid 2 is arranged in front of the screen 1, and the vertical light-shielding plates 2a at both ends of the grid are rotatably supported by the side plates 3a on both sides of the frame 3, and Shading grid 2
By temporarily fixing the upper and lower portions of the
Can be tilted back and forth with respect to the screen 1 within a predetermined angle range.

That is, as shown in FIG.
A bolt insertion hole is formed in the center of the light shielding plate 2a at the center of the light shielding plate 2a, and the bolt 4a is inserted from the outside of the side plate 3a and fixed with the nut 4b from the inside of the light shielding plate 2a. The light-shielding grid 2 is mounted so as to be able to rotate back and forth with the support shaft 4a as a support shaft. And the frame body side plate 3
As shown in FIG. 7, a bolt insertion hole is drilled in the upper and lower portions of a, and a nut 5a is welded to the inside of the side plate 3a.
A temporary fixing bolt 5a is screwed into the nut 5b, and the light-shielding plates 2a on both sides of the lattice are pressed by the tips of the bolts 5a, thereby temporarily fixing the light-shielding lattice 2 so as not to rotate. Therefore, if the bolts 5a for temporary fixing are loosened and tilted back and forth so as to have a desired angle while rotating the grid 2 for light shielding, and the bolts 5a for temporary fixing are tightened in this state, light shielding can be easily performed. The inclination angle of the grid 2 can be adjusted.

The light-shielding grid 2 is the same as described above.
When it is parallel to the screen 1, that is, when it is perpendicular to the ground, the vertical and horizontal light shielding plates 2a and 2b are slightly inclined toward the convergence point P. In addition, as the light-shielding grid, one in which only the horizontal light-shielding plate 2b is slightly inclined may be used.

An image projection screen having such a configuration is as follows.
For example, when the position of the preferable convergence point P is moved due to the change of the position of the projector M, the vertical and horizontal light-shielding plates are adjusted to the convergence point after the movement simply by adjusting the inclination angle of the light-shielding grid in the above-described manner. It has the advantage that it can be oriented so that good visibility can be maintained.

The range of the inclination angle of the light-shielding grating 2 may be appropriately set in consideration of the moving range of the convergence point P. However, in practice, a range of ± 20 ° can sufficiently cope with it. In addition, the manner in which the light-shielding grid 2 can be freely tilted is not limited to the manner of this embodiment, and various attachment means can be employed.

[0032]

As is apparent from the above description, the image projection screen of the present invention can shield light even when the surroundings are installed in a bright place or when the output of the light source of the projector is not so large. The contrast of the screen image is improved by the screen grid, and the visibility of the screen image and the ratio of the projected light rays are small due to the horizontal light shielding plate or the horizontal and vertical light shielding plates of the light shielding grid, so that the visibility is greatly improved. It has a remarkable effect of being improved.
In particular, if the light-shielding grid is attached so that it can be tilted back and forth,
In addition to the above-described effects, even when the positional relationship of the projector or the like with respect to the screen changes, it is possible to obtain an effect that good visibility can be maintained only by adjusting the angle of the light-shielding grid.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an image projection screen according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the screen.

FIG. 3 is an explanatory diagram showing a relationship between the screen, a projector, a viewpoint, and a convergence point.

FIG. 4 is a perspective view showing an image projection screen according to another embodiment of the present invention.

FIG. 5 is a vertical sectional view of the screen.

FIG. 6 is a partially enlarged sectional view of the screen.

FIG. 7 is a partially enlarged sectional view of the screen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screen 2 Light-shielding grid 2a Vertical light-shielding plate 2b Horizontal light-shielding plate 3 Frame E Viewpoint P Convergence point M Projector

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-172939 (JP, A) JP-A-1-209436 (JP, A) JP-A-2-304541 (JP, A) JP-A-62-162 147444 (JP, A) JP-A-56-8182 (JP, A) JP-A-3-54544 (JP, A) JP-A-4-223199 (JP, A) JP-A-62-289823 (JP, A) Hira 4-6044 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 21/60 G02B 26/02

Claims (3)

(57) [Claims] 1. A light shielding grid assembled by intersecting a large number of light shielding plates vertically and horizontally on a front surface of a screen having a narrow viewpoint range, and at least each light shielding plate in a horizontal direction is virtually extended forward. An image projection screen characterized by being slightly inclined in a direction passing through a specific convergence point range between a viewpoint range and a projector. 2. The image projection screen according to claim 1, wherein each of the vertical and horizontal light shielding plates of the light shielding grid is slightly inclined in a direction passing through a convergence point range when virtually extended forward. 3. The screen is surrounded by a frame, and a light-shielding grid arranged in front of the screen is attached to the inside of the frame so that the screen can be inclined back and forth within a predetermined angle range with respect to the screen. The video projection screen according to claim 1.