JPS5947519B2 - television projection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television projection device that obtains an enlarged color image by projecting three primary colors. This is intended to make it possible to freely change the magnification rate without the need for adjustment.

Method of obtaining color images by projecting three primary colors - Italy
is shown in Figure 1.

In FIG. 1, each projector is arranged inline, but this may also be in a delta arrangement or the like. In the figure, 1 is the projection screen surface, 2 is the red projector, 3 is the green projector, 4 is the blue projector, and 5, 6, and T are the projection optical axes of each projector 2, 3, and 4. be. In addition, as the projection optical system of each projector 2, 3, 4, there is one using a refractive optical system, but C
For RT projection, a Schmitt optical system with high light utilization efficiency is used.

In such a color television image projection device that projects three primary colors, if you want to change the magnification of the projected image, if you use a refractive optical system, you must change the lens position for each projector. In the Schmitt optical system shown in Figure 2, it is necessary to change the position of the cathode ray tube for each projector. In Figure 2, 11 is a spherical reflection. A mirror, 12 a Schmitt correction lens, and 13 a projection cathode ray tube.

In this case, as can be seen from FIG. 1, in the initial state, the projection optical axes of the projectors 2, 3, and 4 coincide with each other at the center of the screen surface 1. 3.
If we leave the arrangement in step 4 unchanged and only change the projection distance (enlargement ratio) of each projector, the optical axes will no longer coincide at the center of the screen surface after movement, as shown in Figure 3. In FIG. 3, 1 is the position of the projection screen surface after the change, and 1' is the position of the projection screen surface before the change. The fact that the projection optical axes 5, 6, and T of each projector 2, 3, and 4 do not match at the center of the screen surface 1 means that convergence correction is performed in the initial state and the three primary color images are projected onto the screen surface. ,
By changing the projection distance, the superimposed objects can be
The situation is the same as when the static convergence is out of alignment. Therefore, if you want to correct this, the third
Projectors 2 on both sides of each projector 2, 3, and 4 shown in the figure
- Either change the projection direction of 4 and readjust it so that the projection optical axes 5, 6, and T intersect at the center of the screen surface 1, or use the projectors 2 and 4 on both sides to It becomes necessary to move the position in some way, and 3
In a projection device that obtains a color image by primary color projection, changing the magnification ratio is a very complicated problem. In addition, the projection distance for each projector can be changed by changing the position of the lens as described above, or in the case of a Schmidt optical system, by changing the position of the prune tube surface D relative to the spherical reflector 11. However, as shown in Figure 4, the same lens B,
Although it is possible to change the projection distance of each projector 2, 3, and 4 by the same amount by adding , respectively, the problem that the static convergence shifts due to changing the projection distance in that case is It remains.

The present invention eliminates the above-mentioned complexity that occurs when changing the projection distance (magnification rate) in three primary color projection, and provides a method of changing the magnification rate very easily without convergence shift. That is. An embodiment of the present invention is shown in FIG.

That is, in this embodiment, each primary color projector 2, 3, 4
A common large-diameter lens 8 is provided on the front surface of each lens. With this structure, it is possible to change the position of the optimal focus plane (change the magnification) and simultaneously change the projection direction of each primary color projector 2, 3, and 4, so that multiple primary color images can be displayed. In a device that projects an enlarged color image, it becomes extremely easy to change the enlargement ratio.

In FIG. 5, 5, 1' indicate the projection optical axes of the projectors 2 and 3 when the lens 8 is not provided. Also this lens 8
By moving the position back and forth, it is also possible to continuously change the size of the projected image without static convergence deviation.

As another method, as shown in FIG. 6, a projection distance converting D lens 8 is attached to the front surface of the three primary color projectors 2, 3, and 4 in accordance with the arrangement of the projectors. However, in this case, the center lens 8b is connected to the center of the lens and the projector 3.
The projection optical axes 6 of the left and right projectors 2 are aligned, but the left and right projectors 2
, 4, the distance between each lens is set so that the center 9 of the lens is located inside the projection optical axis of the projectors 2 and 4. Further, the distance between the lenses at this time is selected to a value such that each projection optical axis coincides with the center of the new projection screen image after conversion. By doing so, when the conversion lens 8 is attached, you can move only the screen surface and bring it to the optimal focus position, making it extremely easy to change the magnification ratio to suit your taste. You can get it. In addition, in Figure 6, 5
"・T' is the projection optical axis when there is no lens 8, 5,
1 is the projection optical axis when the lens 8 is attached. Another method? Projector 2 on both sides as shown in the figure
, 4, and a wedge-shaped prism 10 for converting only the projection direction may be attached to one surface of the lenses 8a, 8c. Of course, in this example as well, the same effects as in each of the above embodiments can be obtained. Moreover, this method can produce the same effect whether the projector is arranged in-line or in delta.

As explained above, according to the present invention, a common lens is installed for each primary color projector, or the same number of lenses as the projectors are installed in front of each primary color projector, thereby improving coherence. Projection distance (
magnification ratio) can be easily changed.

[Brief explanation of the drawing]

1 to 4 are diagrams showing a conventional television projection device, and FIGS. 5 to 7 are diagrams each showing a television projection device according to an embodiment of the present invention. 1... Screen surface, 2...
...Projector for red, 3...Projector for green, 4
...... Blue projector, 5, 6, 7...
. . . Projection optical axis, 8 . . . Lens for projection distance conversion, 10 . . . Prism for projection optical axis conversion.

Claims (1)

[Claims] 1. In a projection television device that projects a plurality of primary color images to obtain an enlarged projected image, a lens common to each of the primary color projectors is attached to the front of each primary color projector. A television projection device that simultaneously changes the projection distance and projection direction of each primary color. 2. The television projection device according to claim 1, wherein a common lens is disposed in front of each projector so as to be movable in the main axis direction. 3. In a projection television device that projects multiple primary color images to obtain an enlarged projected image, the same number of lenses as the projectors are attached to the front of each primary color projector, and the projection distance of each primary color projector is varied. and a television projection device in which the projection direction of the primary color projector is changed by shifting the center of at least one of these lenses from the optical axis of the primary color projector facing the lens. 4. In a projection television device that projects a plurality of primary color images to obtain an enlarged projected image, the same number of lenses as the projectors are provided in front of each primary color projector to vary the projection distance of each of the primary color projectors. and a wedge-shaped prism is arranged for at least one of the primary color projectors to change the projection direction of the at least one projector.