JPH0225840A - Transmissive graph projector - Google Patents

Abstract

PURPOSE:To prevent the difficulty of viewing an image from a front seat by lighting a transmissive graph horizontally placed with light having an optical axis which is in parallel with the surface of a projection screen and inclined toward a vertical direction and forming the image on the surface of the projection screen by an image- formation lens whose optical axis is made to turn to the vertical direction and as reflecting mirror which is inclined toward the vertical direction. CONSTITUTION:The light from a source 12 is emitted in the direction which is in parallel with the surface of the projection screen 2 and where it is inclined by about 45 deg. toward the vertical direction. After the light from the light source 12 is reflected by the reflecting mirror 13 and condensed by a condensing lens 14, it lights the transmissive graph A. After the light is transmitted through said graph A, the image is formed on the surface of the projection screen by the image-formation lens 16 and a reflecting mirror 17 and the pattern (a) of said graph A is projected as the image (a'). At such a time, the surface of the projection screen 2 and in a state where it is deflected by 45 deg. toward the vertical direction, so that the image is appropriately formed on the surface of the projection screen 2. Thus, it is possible to view the projected image from the front of the projection screen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a perspective graph projector, also called an overhead graph projector or viewgraph.

[Conventional technology]

Conventionally, this type of perspective graph projector places the perspective graph to be projected on a transparent table placed horizontally, illuminates it from below, and uses an imaging lens and a reflecting mirror placed above. is configured to project the image of the perspective graph onto the projection screen surface.

[Problem to be solved by the invention]

In the conventional projector described above, the perspective graph is illuminated vertically from directly below, so in order to properly project the perspective graph onto the projection screen surface, it is necessary to use a light source, an imaging lens,
It is necessary to align the optical axis formed by the reflecting mirror directly with the projection screen surface.

Therefore, it is necessary to position the projector in front of the projection screen surface, and there is a problem in that dust in front of the projection screen surface obstructs the projector and makes it difficult to see the projected image.

SUMMARY OF THE INVENTION An object of the present invention is to provide a perspective graph projector that allows a projected image to be viewed from the front of the projection screen without being obstructed by the projector.

[Means to solve the problem]

The perspective graph projector of the present invention includes a light source system that illuminates a perspective graph placed horizontally with an optical axis that is parallel to the projection screen surface and inclined in the vertical direction, and a lens that is arranged on the optical axis and that has a lens optical axis. It includes a vertically oriented imaging lens and a vertically inclined reflective mirror located above the imaging lens.

[Effect]

With the above-described configuration, it is possible to project light onto the projection screen diagonally from the side to form a perspective graph on the projection screen surface, and it is possible to arrange the projector diagonally in front of the projection screen.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1 is a front view of an embodiment of the present invention, and FIG. 2 is a side view thereof. In FIG. 0, 1 is a projector, 2 is a projection screen, and the projection screen 2 is arranged vertically and vessel l
is arranged diagonally in front of this projection screen 2.

The projector I has a light source box 11 with a transparent upper surface, and a perspective graph A to be projected is placed on the upper surface. Inside this light source box 11 are a light source 123, a reflecting mirror 13. A condensing lens 14 is disposed to constitute a light source system that illuminates the perspective graph A by emitting light from the light source 12 obliquely from below to the upper surface. Here, the light from the light source 12 is emitted in a direction that is parallel to the surface of the projection screen 2 and inclined at approximately 45 degrees to the vertical direction.

Further, a support 15 that projects obliquely upward is fixed to the light source box 11, and an imaging lens 16 and a reflection mirror 1 are attached to this support.
7 is supported. The imaging lens 16 is placed on the optical axis of the light emitted from the light source box 11, with its optical axis oriented vertically. Further, the reflecting mirror 17 is located approximately directly above the imaging lens 16, at the same height as the center of the projection screen 2, and at an angle of 45° with respect to the vertical direction.
It is tilted.

According to this configuration, the light from the light source 12 is reflected by the reflection mirror 13 and condensed by the condensing lens 14, and then illuminates the perspective graph A. Furthermore, after passing through the perspective graph A, the image is formed on the surface of the projection screen 2 by the imaging lens 16 and the reflection mirror 17, and the pattern a of the perspective graph A is projected as an image a'. At this time, perspective graph A, light source 1
The relationship between the reflective surface of the optical axis 1 reflecting mirror 17 from 2 and the surface of the projection screen 2 is the angular relationship schematically shown in FIG. The image is parallel to and offset by 45 degrees in the vertical direction, and is suitably imaged on the surface of the projection screen 2. Note that in each figure, image a# indicated by a virtual line indicates the image formation position when the reflection mirror 17 does not exist.

Therefore, since this projector can image and project the perspective graph A onto the projection screen 2 from diagonally in front of the projection screen 2, there is no need to place the projector in front of the projection screen. Since the projector does not get in the way of the front seat of No. 2, and the light is incident on the projection screen 2 diagonally, the distance between the screen 2 and the projector 1 must be adjusted to obtain the same screen size. Can be made smaller.

Note that by reversing the direction of inclination of the reflection mirror 17, it is also possible to perform projection from the right side as viewed from the projection screen 2. Also, the angle that the optical axis makes in the vertical direction is 1
It can also be set at an appropriate angle of 0° to 45°.

〔Effect of the invention〕

As explained above, the present invention provides an imaging lens for illuminating a perspective graph placed horizontally with an optical axis parallel to the projection screen surface and tilted in the vertical direction, and with the optical axis of the lens oriented in the vertical direction; Since the image is formed on the projection screen surface by a reflecting mirror tilted in the vertical direction, it is possible to project onto the projection screen surface from diagonally in front of the projection screen. This arrangement has the effect of eliminating visibility from the front seat.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of an embodiment of the projector of the present invention, FIG. 2 is a partially cutaway side view, and FIG. 3 is a schematic diagram for explaining the image forming state. FIG. 1... Projector, 2... Projection screen, 11...
Light source box, 12... Light source, 13... Reflection mirror 14
...Condensing lens, 15... Support column, 16... Imaging lens, 17... Reflection mirror, A... Perspective graph,
a... Projection pattern, a'... Projected image, a''...
virtual image. 13, 1 mifu

Claims (1)

[Claims] 1. A light source system that illuminates a perspective graph placed horizontally with an optical axis parallel to the projection screen surface and tilted in the vertical direction;
An imaging lens disposed on the optical axis and with the optical axis of the lens oriented vertically, and a reflection mirror positioned above the imaging lens and tilted in the vertical direction. A perspective graph projector characterized in that it is configured to form an image onto a projection screen surface from diagonally in front of the projection screen.