JPS59165042A - Projector for deskwork - Google Patents

Abstract

PURPOSE:To form a normal projection image on a projection screen by operating plural oscillation supporting means to incline an original placing plate and a focusing optical lens properly. CONSTITUTION:The original placing plate 22 is supported on the upper part of a base plate 21 of a projector by plural drawing hinges 23 so as to be inclined in two directions with respect to a surface intersected with an optical axis at right angles. A strut 24 is formed on the side part of the base plate 21 and a projecting device 25 is formed on the upper part of the strut 24. A bending oscillation member 26 to which a lens fitting board 28 mounting the focusing optical lens 27 is fitted is fixed on the lower end of the projecting device 25. The focusing optical lens 27 can be held so as to be inclined in two directions with respect to the surface intersected with the optical axis 29 at right angles by bending the bending oscillation member 26 properly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an office projector, also called an overhead projector, and more particularly to a document holder for placing a document to be projected and a document holder for placing the document to be projected. The present invention relates to an office projector equipped with a focusing optical lens for receiving projection light from a document placed on a table and creating a projection image on a projection surface.

Prior Art This type of conventional office projector is generally used by being installed directly in front of a projection screen to perform projection. If the projector is placed in the same direction as the viewing direction with respect to the projection screen, the projector itself may obstruct the view of the person viewing the projection screen behind it. In order to avoid this, it is conceivable to project the image from an oblique direction to the projection screen instead of installing the projector directly in front of the projection screen. In this way, as schematically illustrated in FIG. 1 of the accompanying drawings, the projector 10 is located away from the viewing direction P of the projection screen 1, so that the projector 10 does not interfere with the person viewing the projection screen 1. It will never be. However, in the conventional projector 10, the document placing table 11 on which the original 2 to be projected is placed is fixed to a surface perpendicular to the optical axis 13, and the document placing table 11 is unnecessarily fixed.
A focusing optical lens (not shown in the figure), which is provided on the projection device 12 supported on the document 1 and receives the projection light from the original 2 to create a projected image on the projection screen 1, is also oriented toward the optical axis 13. Since the document 2 is fixedly held on a plane perpendicular to the projection screen 1, the projected image 3 of the document 2 projected onto the projection screen 1 will not be an exact square, as shown in FIG. 1, and will be distorted. The image becomes difficult to see and becomes out of focus. In the conventional projector configuration, there was no means for correcting image distortion or focus error in such cases.

OBJECTS OF THE INVENTION An object of the present invention is to provide an office projector that eliminates the problems of conventional projectors as described above.
Structure of the Invention According to the present invention, there is provided a document placing table for placing an original to be projected, and a device for receiving projection light from the original placed on the document placing table 11 to create a projected image on a projection surface. a first rocking device for supporting the document table so that it can tilt in two directions perpendicular to the optical axis of the projection light; supporting means, and two directions perpendicular to y with respect to the optical axis of the projection light in order to correct a focal shift of the projection light from the original document caused by the tilting of the original table by the first swing support means. a first swinging support means for supporting the focusing optical lens so as to be tiltable; and when projecting from an oblique direction to the projection plane, the first swinging support means By operating the rocking support means, the document mounting table and the focusing optical lens can be tilted with respect to the optical axis as appropriate so that a projected image without distortion and out of focus is formed on the projection plane. be made possible.

Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on FIGS. 2 to S of the accompanying drawings.

FIG. 2 is a schematic perspective view showing the document mounting table of the office projector as an embodiment of the present invention, and FIG. 3 is a schematic perspective view showing the document mounting table of the office projector shown in FIG. FIG. 2 is a schematic perspective view showing a portion of the projection device.

The perspective view of FIG. 3 shows the second distortion swinging member for easy viewing.
The perspective view in the figure is a view from a different direction.

As shown in FIG. 2, the office projector of this embodiment includes a base 21 housing a projection light source and a projection condensing lens, which will be described later. On the top of this base 21, there is a JQ
A bucket mounting table 22 is provided, and this document mounting table 22 has a plurality of drawer butterfly plates 2 that can freely change the amount of drawer and hold the document.
It is supported on the base 21 using three components. These drawer butterfly plates 23 constitute a seventh swinging support means for supporting the original document placement table 22ft, and each drawer butterfly plate 23 can be appropriately pulled out from the trap to support the original document placement reference surface 22A.

That is, with respect to the plane perpendicular to the optical axis, the original table 22 is tilted at an angle θ in two directions, that is, in the six directions and in the B direction.
It can be held tilted by A and θB respectively.

A support 24 is provided to stand upright from the side of the base 21, and a projection device 25 is provided at the upper end of this support 24, as shown in FIG. The projection device 25 is located directly above the document mounting table 22, and the projection device 25
The upper end of the distortion swinging member 26 is fixedly attached to the lower end of the distortion swinging member 26 . A lens mounting plate 28 on which a focusing optical lens 27 is mounted is attached to the lower end of the distortion swinging member 26.

The distortion swinging member 26 constitutes a third swinging support means for supporting the focusing optical lens 27, and by appropriately distorting it,
In the λ direction, that is, the a direction and the b direction, the focusing optical lens 21 can be held tilted by the tilt angles θ8 and θb, respectively.

At the top of the projection device 25, there is a reflecting mirror 3 for reflecting the projection light that has passed through the focusing optical lens 2T toward the projection surface.
0 is attached so that the angle can be adjusted.

The principle by which distortion and defocus of a projected image can be corrected when projecting from an oblique direction to a projection surface in an office projector having such a configuration will be explained with reference to FIG.

The second figure schematically shows a state in which the original 2 placed on the original mounting table 22 is projected onto the projection screen 32 which is inclined by an angle θ3 with respect to the projection source axis 31 in the − plane.

First, when the document mounting table 22 and the focusing optical lens 27 are maintained in a plane perpendicular to the original axis 29 as shown by the dotted line, the projection light source 33 in the base 21 is Optical lens 34, original 2, focusing optical lens 2
The light projected onto the projection screen 32 via the mirror 30 and the reflection mirror 30 has a length β? becomes longer than the length α2 of the projected image of the upper portion of the original 2 with respect to the optical axis 31, and as a result, the projected image as a whole is distorted. Therefore, by appropriately pulling out the drawer butterfly plate 23 that is the first swing support member, the optical axis 3 on the projection screen 32 is
The length α1 of the projected image of the original 2 in the upper part with respect to 1 is the same as the length β1 of the projected image of the original 2 in the lower part with respect to the optical axis 31. By tilting the surface by an angle θ1, the distortion of the projected image as a whole is corrected. When the original 2 is tilted by the angle θ1 in this way, the original image reaching the focusing optical lens 2T has a difference in distance and a focus difference, so the distortion swinging member which is the first swinging support means 26 and shift the correction angle θ with respect to the reference plane trap of the focusing optical lens 27 to correct the focal difference, the focal error can also be eliminated. The state after such correction is shown by a solid line in the figure, and thereby the projection screen 32
The normal projection image imaged above is designated by reference numeral 4.

The above explanation was about the case where the projection screen 32 is inclined in one plane with respect to the projection optical axis 31.
Even if the projection screen 32 is tilted in another plane perpendicular to the above-mentioned - plane, the distortion of the projected image can be prevented by operating the first and first swing support means on the same principle as described above. It will be appreciated that the focus deviation can be completely corrected.

Similarly, in the aforementioned embodiment of the present invention, a plurality of drawer butterfly plates were used as the first swing support member, and a distorted swing member was used as the first swing support member, but the present invention is not limited to this, and may be of any type as long as it allows the original table and the focusing optical lens to be tilted arbitrarily.For example, the distortion swinging member may also be used as the first swinging support member. May be used.

Effects of the Invention Since the office projector of the present invention has the above-described configuration, as shown in FIG. Even in the case of projection, it is possible to obtain a projected image without distortion and out of focus, such as a projected image 5 shown by a solid line. In this way, when projecting onto the projection screen 35 from an oblique direction, the conventional projector would produce a distorted and out-of-focus projected image as shown by the dotted line. According to the projector, as described above, by operating the first swing support means 23 and the first swing support means 2B to appropriately tilt the document mounting table 22 and the focusing optical lens 27, A normal projected image 5 can be created on the projection screen 35. Therefore, viewing direction P
The normal projected image 5 can now be viewed without being obstructed by the projector.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a projection state by a conventional projector, FIG. Figure 3 is a schematic perspective view showing the projection device portion placed on the document table of the office projector of the present invention; Figure 3 is a principle diagram for explaining the principle of projection by the office projector of the present invention; FIG. 2 is a schematic diagram illustrating a projection state by the office projector of the present invention. 2...Manuscript 21...Base 22...
...Document placement table 22A...Document placement reference surface 23...Drawer butterfly plate 24...
・Strut 25... Projection device 26...
Distortion swinging member 2T...Focusing optical lens 28...Lens mounting plate 29...
Optical axis 30... Reflecting mirror 32... Projection screen 33... Projection light source 34... Projection condensing lens ○ -

Claims (1)

[Claims] A document mounting table for placing an original to be projected, and a focusing optical lens for receiving projection light from the placed original and creating a projected image on a projection surface. In the office projector, a seventh swing support means for supporting the document table so as to be tiltable in one direction perpendicular to y with respect to the optical axis of the projection light; In order to correct the focal shift of the projection light from the original document caused by the tilting of the original table by the swing support means, the focal point is tiltable in one direction perpendicular to the optical axis of the projection light. a second for supporting the mating optical lens;
An office projector comprising: a swinging support means;