JP2004309528A - Video image projection device in dome screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize accurate extinction at a joint part of projected images when projecting and joining the plurality of projected images on a dome screen. <P>SOLUTION: In the projection device where a shielding member for shielding the joint of the projected image is provided at a position deviated from the position of the principal point of a projection lens so as to lower the illuminance of the joint thereof, with the use of the shielding member 1A whose shielding part is three-dimensionally constituted so that its shape may be similar to the shape of the joint T of the projected image PA on a dome screen S, the shielding part of the shielding member is positioned at a distance at which the the shielding part is similar to a relation between the joint T of the projected images PA on the dome screen and that on the principal point RA of the lens. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a video image projector in a dome screen, and more particularly to a video image projector using a video image projector optimal for a planetarium or the like.
[0002]
[Prior art]
For example, the idea of applying a video image projector that projects an image generated on an image display unit such as a liquid crystal display to a screen via an optical system to a planetarium is already known. Since this type of projector can easily obtain a moving image with a large angle of view, it is extremely useful to use this for a planetarium.
[0003]
[Problems to be solved by the invention]
By the way, in a video image projector as described above, unlike a conventional projector using an original plate composed of an optically transparent portion and a non-transparent portion such as a film, the outside of an image display area is displayed dimly and apparently. A phenomenon occurs as if a frame-shaped contour is generated around the projected image. That is, in the essence of the video image projector that actively emits light to be an image from the image display unit, even when the periphery of the display area is displayed in black, the black display unit is also projected as light. Cause a phenomenon. In particular, at the technical level at the time of the filing of the present invention, when a liquid crystal or DLP video image projector is used, the black level outside the image display area is projected brightly on the screen due to the low contrast ratio of the projector. Tends to be easy. In other words, when the contrast ratio of the projector is 500: 1, if the illuminance of the projected image is 50 lux at the maximum, the minimum illuminance is 0.1 lux, and a black image can be obtained in a completely dark environment such as a planetarium. Even when the image is projected, the whole projected image appears to be white.
[0004]
Of course, the above-mentioned phenomenon does not constitute any problem in the case where a single video image projector is used as in a normal theater, and the image is projected on a screen whose size and position are fully defined in advance in the image plane. In the first place, the audience was not even aware that such a phenomenon had occurred. However, when this is used in a planetarium or a dome screen of an all-sky all-around type, the above-mentioned phenomenon has become apparent as a problem.
[0005]
In the planetarium, it is well known that auxiliary stars are used to project various stars, landscapes, objects, etc. in addition to the starry sky using a star projector, but in this case, the entire surface of one dome screen is projected as a single video image. The projected images projected by the individual video image projectors occupy only a part of the dome screen, and are not occupied by the projectors. When an image projector is used, the frame-shaped outline becomes conspicuous in a dark dome screen. In other words, in a planetarium, since the screen is dark except for the very small part where the stars are projected due to the essence of reproducing the starry sky, there is a problem that the frame-like outline of the video image projector becomes conspicuous. Occurs. For example, when projecting a planet as a magnified image, a frame-shaped outline occurs even though the other parts must be jet black and have to be melted into the dome screen surface.
[0006]
In addition, the above phenomena are not only planetariums that scientifically strictly reproduce celestial phenomena, but also general dome screens that obtain various simulations by projecting projected images such as natural phenomena in all directions around the sky. Common. That is, also in this case, the entire surface of one dome screen is not occupied by a single video image projector, but is projected by individual video image projectors, so there may be a dark screen surface on the production, Such a phenomenon may occur.
[0007]
On the other hand, in the case where one apparent projection image such as a starry sky or a continuous skyline is obtained by connecting and synthesizing it with the same type of projection image or a projection image from another video device, the joint portion is formed by a frame-shaped outline. There was a problem that the illuminance was increased, resulting in an unnatural projection image.
[0008]
As one of the measures for solving the above problems, a process of processing a video signal and adding a gradation (blur) at a joint is known. However, there is a problem that an expensive dedicated computer is required. Further, even if gradation is performed by the above-described signal processing, there still remains a problem that in a projector having a bright black level, the overlapping portion of the black level is projected more brightly and the seam becomes difficult to see. To make this frame inconspicuous, a very high-contrast CRT projector must be used, but this type of projector is expensive and high-contrast projectors are generally used. The illuminance was low, and the brightness was insufficient to project colorful images on the entire dome.
[0009]
As another measure, when projecting a projected image using a video image projector, provide a shield at a position off the principal point of the projection lens so that the brightness at the periphery of the projected image is continuously reduced. Is known as an invention of the present applicant (Japanese Patent Application Laid-Open No. 8-171344). According to the present invention, the image including the black level of the unnecessary portion is not displayed on the screen, and the projected image has an appropriate gradation due to the positional relationship between the occlusion and the principal point of the lens.
[0010]
The invention described above relates to a case where a single image is projected on a dome screen, and even when a plurality of projected images are connected, when the projectors that project images to be connected have the same condition with respect to the dome screen, the lens is If they are shielded at the same distance from each other, their gradations become equal, and there is no problem even if a flat shielding plate as disclosed in JP-A-8-171344 is used.
[0011]
However, in an actual dome screen, the projectors that project images to be connected are the same as the dome screen due to the arrangement of the audience seats or the installation environment of the projector such as another projector has already been installed. It is not realistic to arrange on condition. On the other hand, instead of dividing one projection image equally, for example, as shown in FIG. 1, the vicinity of the dome horizontal line is projected by a plurality of target projectors with respect to the dome Z axis, and the pole of the dome is set to another projector. It is common to divide the image non-uniformly so that the image is projected. In such a case, it is impossible to compose one image by synthesizing each image due to distortion when projected on a dome screen. It has been performed to correct the image to be projected from the deformation, but when using a flat shielding plate as in the above-mentioned known invention, the resulting gradation is distorted on the dome screen in a distorted state. Since the projection is performed, a state in which the joint of the projected projection image does not match the gradation occurs.
[0012]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the problems of the prior art described above, and when projecting projected images on a dome screen by connecting projected images from a plurality of video image projectors, In a projection device in which a shielding member for shielding the joint is provided at a position deviated from the principal point position of the projection lens so as to reduce the illuminance of the joint, a shielding portion of the shielding portion is formed so as to be similar in shape to the joint of the projected image on the screen surface. It is characterized in that the shielding portion of the shielding member is positioned at a distance similar to the relationship between the principal point of the lens and the joint of the projected image on the screen surface by using a shielding member having a three-dimensional shape.
[0013]
Also, here, when connecting the projection images from a plurality of video image projectors and projecting the projection image on the dome screen, a shielding member for shielding the joint is used as a main point of the projection lens so as to reduce the illuminance of the joint of the projection image. In a projection device provided at a position deviated from the position, when the projected image is circular, the relationship between the principal point of the lens and the joint of the projected image on the screen surface using a shielding member provided with a circular transparent portion on a plane. Also disclosed is an invention characterized in that the shielding portion of the shielding member is positioned at a distance that is similar to the above.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a plurality of projected images PB connected circumferentially by dividing and projecting the vicinity of the horizontal line of the dome screen S with respect to the dome Z axis by a plurality of video image projectors (not shown). And the other video image projector 4 projects a polygonal projection image PA in the vicinity of the dome screen, and joins the projection image PA to each of the projection images PB to form a whole sky projection. An example of obtaining an image is shown. In this example, since each video image projector is installed at a position off the center of the dome screen, which is an ideal position, each video image projector is projected from each video image projector so that distortion does not occur when projected on the dome screen. The image to be corrected has been modified.
[0015]
In the above case, the illuminance at the joint T of the projected image PA (PB) is reduced in a gradation manner by installing the shielding member 1A (1B) for partially shielding the projection light beam on the front surface of the lens of the video image projector. . At this time, by shielding at a distance similar to the relationship between the dome screen S and the lens principal point RA (RB), it is possible to ensure that the width of the projection image of the shielding portion is equal without distortion in the gradation. By using the screen, a similar shielding is applied to the screen, and the light is shielded in accordance with the projection position of the joint of the projected images, thereby obtaining a gradation exactly along the joint of the projected images. Here, for this purpose, the lens principal point RA is formed by using a shielding member 1A (1B) in which the shape of the shielding portion is three-dimensionally configured so as to be similar to the shape of the joint T of the projected image PA (PB) on the screen surface. The shielding portion of the shielding member is located at a distance similar to the relationship between (RB) and the joint of the projected image on the screen surface.
[0016]
FIG. 2 is a view for explaining the configuration of the above-mentioned shielding member, taking as an example the shielding member 1A of the video image projector 4 for obtaining a projected image PA near the dome screen. The shielding member 1A has a dome shape similar to that of the dome screen S, and by providing a transmissive portion 2A and a non-transmissive portion 3A therein, the shape and position of the shield portion can be changed to the shape of the joint of the projected image on the screen surface. It is three-dimensionally configured so as to be similar to the position (here, a polygon curved in a dome shape). In this embodiment, the cutout window is provided in the non-transmissive shielding member 1A to obtain the transmissive portion 2A and the non-transmissive portion 3A. However, the transmissive portion 2A may be configured to be transparent without being cut out. Of course. The shielding member 1A may have a shape of the shielding portion (specifically, the periphery of the transmission portion 2A) similar to the shape of the joint of the projected image on the screen surface, and it is not always necessary that the entire shielding member has a dome shape. Absent. However, as a means for obtaining the shape of the shielding portion similar to the shape of the joint of the projected image on the screen surface, the most reasonable and easy method is to form the entire shielding member into a dome shape and provide a transmission portion thereat.
[0017]
In the above embodiment, the shape of the shielding portion is three-dimensionally configured so as to be similar to the shape of the joint of the projected image on the screen surface. However, when the projected image PC is circular as shown in FIG. It is not necessary to form the shape of the shielding portion three-dimensionally, and the shielding member 1C only needs to use a circular transparent portion 2C on a plane. Similarly to the above-described embodiment, the shielding member 1C also has the shielding portion positioned at a distance similar to the relationship between the lens principal point RC (RB) and the joint T of the projected image PC (PB) on the screen surface. The shielding member 1C obtains a shielding portion by providing a transparent portion 2C and a non-transmitting portion 3C on a flat plate, but the transparent portion 2C may be a cutout window or a transparent portion as in the above-described embodiment.
[0018]
FIG. 4 is an explanatory diagram for explaining the operation of the above embodiment by taking the shielding member 1C as an example. In the drawing, reference symbol P indicates an image display unit (original plate surface) of a video image projector. As is clear from this figure, G: H = G ′: H ′, and the brightness of the joint T of the projected image PC is reduced at the same rate everywhere with respect to the original brightness.
[0019]
By the way, when a video image projector is used as an auxiliary projector in a planetarium, a black level portion in an image is also projected as having brightness as described above in the present invention. If it overlaps a star projected from a sphere, it will hinder the projected image. In such a case, the above-mentioned phenomenon can be avoided by providing a movable shielding member in the video image projector by applying the technology disclosed in the present invention and inserting the movable shielding member into the black level portion as necessary. It becomes possible.
[0020]
【The invention's effect】
According to the video image projection apparatus of the present invention having the above-described configuration, even when a plurality of projection images are projected on the dome screen and connected, a precise dimming of a joint portion is possible, so that a liquid crystal having a low contrast ratio is used. There is no problem even if a video image projector of the DLP system is used, and it is possible to project a bright and colorful image by using a video image projector that is cheaper and has higher power than those conventionally used. .
[Brief description of the drawings]
FIG. 1 is a perspective view of a video image projection device according to the present invention in use.
FIG. 2 is a perspective view of an essential part of the embodiment.
FIG. 3 is a perspective view of a video image projection device according to another embodiment of the present invention in use.
FIG. 4 is an explanatory view showing the operation of the present invention.
[Explanation of symbols]
S Dome screen PA Projected image T Joint RA Main lens point 1A Shielding member 2A Transmissive part 3A Non-transmissive part 4 Video image projector

Claims (3)

When connecting projected images from multiple video image projectors and projecting the projected image on the dome screen, the shielding member that shields the joint is shifted from the principal point of the projection lens so as to reduce the illuminance of the joint of the projected image. In the projection device provided at the position, using a shielding member in which the shape of the shielding portion is three-dimensionally configured to be similar to the shape of the joint of the projected image on the screen surface, the principal point of the lens and the projected image on the screen surface A video image projection device for a dome screen, wherein a shielding portion of a shielding member is positioned at a distance similar to a relationship with a joint. It has a dome shape similar to a dome screen, with a transmissive portion and a non-transmissive portion provided therein, and uses a shielding member in which the shape and position of the transmissive portion are similar to the shape and position of the joint of the projected image on the screen surface. A video image projection device for a dome screen according to claim 1. When connecting projected images from multiple video image projectors and projecting the projected image on the dome screen, the shielding member that shields the joint is shifted from the principal point of the projection lens so as to reduce the illuminance of the joint of the projected image. In the projection device provided at the position, when the projected image is circular, using a shielding member provided with a circular transparent portion on a plane, a shape similar to the relationship between the lens principal point and the joint of the projected image on the screen surface. A video image projection device for a dome screen, wherein a shielding portion of a shielding member is located at a certain distance.

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