JPH10239773A - Overhead projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the image of an original projected on a projection surface easy-to-view by moving the projected part to a position nearer to the center of the projection surface when it is hardly viewed because it is projected at the lower edge part of the projection surface and the like, as for an overhead projector of such a system that the plain-paper original placed on an original platen is read and projected. SOLUTION: This projector is provided with a turning mechanism 15 turning an image pickup element 13 reading the image of the original 2 placed on the original platen 3 around an X axis and a Y axis which are mutually orthogonally crossed. By turning the element 13 around the X axis and the Y axis by driving the turning mechanism 15, the reading position of the original 2 by the element 13 can be moved. Thus, the image of the original projected on the projection surface is easily and quickly moved to the position nearer to the center of the projection surface where it is easily viewed without executing such troublesome work that the original 2 placed on the platen 3 is moved by hand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead projector for reading an image on a document placed on a document table and projecting the image on a projection surface.

[0002]

2. Description of the Related Art Conventionally, there has been known an overhead projector in which an image of a plain paper original placed on a platen is read and projected. One example of such an overhead projector will be described with reference to FIG. Case 1
A document table 3 on which a document 2 is placed is provided on the upper surface of the document. An illumination light source 4 for illuminating the original 2 placed on the original table 3 and a total reflection mirror 5 for totally reflecting light reflected by the original 2 are provided below the original table 3 in the housing 1. An image sensor such as a two-dimensional CCD 6 for reading an image on the document 2 by receiving light reflected by the total reflection mirror 5 is provided.

Further, the two-dimensional C
A signal processing unit 7 for converting an image signal output from the CD 6 into a display drive signal such as a liquid crystal drive signal, a liquid crystal panel 8 for displaying an image corresponding to the liquid crystal drive signal, and a projection for emitting projection light A light source 9, a cold mirror 10 that reflects visible light of the light emitted from the projection light source 9 toward the liquid crystal panel 8 and transmits infrared light, and a total reflection mirror that totally reflects light transmitted through the liquid crystal panel 8 11
And a projection lens 12 for projecting the light reflected by the total reflection mirror 11 onto a projection surface such as a screen.

In such a configuration, an image of the document 2 placed on the document table 3 is read by the two-dimensional CCD 6, and an image signal corresponding to the read is output from the two-dimensional CCD 6 to the signal processing unit 7. The signal processor 7 converts the image signal into a liquid crystal drive signal, and an image corresponding to the liquid crystal drive signal is displayed on the liquid crystal panel 8. When light emitted from the projection light source 9 is applied to the liquid crystal panel 8 on which such display is performed, the displayed image is changed to the projection lens 12.
Through the projection surface. Therefore, even if the document 2 is plain paper, it can be projected as it is.

[0005]

SUMMARY OF THE INVENTION When explaining to a large number of people while watching an image projected on a projection surface,
If the part to be described is projected on the lower edge of the projection plane, the part may be difficult to see from behind. In addition, when the projected image is enlarged and zoomed, the peripheral portion of the image comes off the screen. In such a case, the original 2 placed on the original platen 3 is moved by hand to adjust the position, and the image of the portion to be projected is moved to a position near the center of the projection surface.

However, it is complicated to move the original 2 by hand during projection to adjust the position. In particular, when performing the enlargement zoom, the position of the document 2 must be adjusted in accordance with the movement of the enlargement zoom point, which is very complicated.

Accordingly, the present invention is to move an image of a document projected on a projection surface to a position near the center of the projection surface for easy viewing without moving and adjusting the position of the document placed on the document table. It is an object of the present invention to provide a possible overhead projector.

[0008]

According to the present invention, an image of a document placed on a document table is read by an image sensor, and an image signal output from the image sensor is converted into a display drive signal by a signal processing unit. In an overhead projector for displaying an image corresponding to the display drive signal on a display unit and projecting the image displayed on the display unit toward a projection surface, the image pickup device is moved around X-axis and Y-axis orthogonal to each other. And an operating unit for driving the rotating mechanism. Therefore, by operating the operation unit to drive the rotation mechanism, the image sensor rotates around the X axis and the Y axis that are orthogonal to each other. By rotating the image sensor about the X axis and the Y axis, the reading position of the document by the image sensor can be moved, and the document placed on the document table is projected onto the projection surface without moving. The displayed image can be moved to an easy-to-see position near the center of the projection plane.

[0009]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG. In addition, the same parts as those described in FIG. FIG. 1 is a side view showing a schematic structure of the overhead projector. An illumination light source 4 for illuminating a document 2 placed on a document table 3 and light reflected from the document 2 are provided inside the housing 1 in the same manner as in the conventional overhead projector described with reference to FIG. A total reflection mirror 5 for total reflection, and a two-dimensional CCD as an image sensor for reading an image of the original 2 by receiving light reflected from the total reflection mirror 5
13, a signal processing unit 7 for converting an image signal output from the two-dimensional CCD 13 into a liquid crystal drive signal as a display drive signal, a liquid crystal panel 8 as a display unit for displaying an image corresponding to the liquid crystal drive signal, and a projection Light source 9 that emits light for use, a cold mirror 10 that reflects visible light of the light emitted from the light source 9 toward the liquid crystal panel 8 and transmits infrared light, and a light that has passed through the liquid crystal panel 8. A total reflection mirror 11 for total reflection, a projection lens 12 for projecting light reflected by the total reflection mirror 11 onto a projection surface, and the like are provided.

The signal processing unit 7 includes an FDD 14
Is connected. This FDD 14 is the two-dimensional CC
The image signal output from D13 is recorded on the FD, and
An image signal recorded on the FD is output.

The two-dimensional CCD 13 is attached to a rotating mechanism 15. The rotating mechanism 15 is provided with the two-dimensional CC.
This is a mechanism for rotating D13 around an X axis (vertical axis) and a Y axis (horizontal axis) orthogonal to each other. This rotating mechanism 1
5 will be described in detail with reference to FIGS.

A base 16 is fixed in the housing 1, and the X-axis frame 1 is rotatably mounted on the base 16 around the X-axis.
7 are connected. A Y-axis frame 18 is connected to the upper part of the X-axis frame 17 so as to be rotatable around the Y-axis, and the two-dimensional CCD 13 is fixed to the Y-axis frame 18.

An X-axis motor 19 is fixed to the base 16, and an X-axis worm gear 20 is connected to a motor shaft of the X-axis motor 19. X-axis worm gear 20 is X
The X-axis gear 21 meshes with an X-axis gear 21 that is rotatable about an axis, and the X-axis gear 21 is connected to rotate integrally with the X-axis frame 17. Here, when the X-axis motor 19 is driven, the X-axis gear 21, the X-axis frame 17, and the Y-axis frame 18 rotate around the X-axis, and the Y-axis frame 18
The two-dimensional CCD 13 fixed to the camera shakes its head in the horizontal direction indicated by the arrow A in FIG.

The X-axis frame 17 has a Y-axis motor 22
Is fixed, and a Y-axis worm gear 23 is connected to a motor shaft of the Y-axis motor 22. Y-axis worm gear 2
Numeral 3 meshes with a Y-axis gear 24 rotatable about the Y-axis, and the Y-axis gear 24 is connected to rotate integrally with the Y-axis frame 18. Here, the Y-axis motor 2
2 is driven, the Y-axis gear 24 and the Y-axis frame 18 rotate around the Y-axis, and the two-dimensional CCD 13 fixed to the Y-axis frame 18 moves the head in the vertical direction indicated by the arrow B in FIG. Shake.

The rotation mechanism 15 is provided with sensors (not shown) for detecting a rotation position in the X-axis direction and the Y-axis direction. Home position management relating to the moving position is performed.

An operation panel (not shown) is mounted on the outer peripheral surface of the housing 1, and an operation section for driving the rotating mechanism 15, for example, a two-dimensional CCD, is provided in the operation panel.
13 are provided with arrow keys (not shown) indicating the swing direction. This operation unit may be of a remote control type.

In such a configuration, the basic operation of the overhead projector, that is, the reading of the image of the document 2 placed on the document table 3 by the two-dimensional CCD 13 and the liquid crystal of the image signal output in accordance with the reading. The conversion into the drive signal, the display of the image corresponding to the converted liquid crystal drive signal on the liquid crystal panel 8, the projection of the image displayed on the liquid crystal panel 8 onto the projection surface, and the like are performed by the overhead of the conventional example shown in FIG. Performed in the same way as a projector. Therefore, even if the document 2 is plain paper, it can be projected as it is.

When the explanation is made while looking at the image projected on the projection plane, the part to be explained is on the lower edge side of the projection plane, and it becomes difficult for a person behind to see, or the projected image is enlarged. When the part to be projected is out of the projection plane due to zooming, the rotating mechanism 15 is driven by operating the operation unit, and the two-dimensional CCD 13 is
Swing around the axis and Y axis. As a result, the reading position of the original 2 by the swung two-dimensional CCD 13 is moved,
The position of the image read by the two-dimensional CCD 13 and projected on the projection plane also moves, and the part to be projected can be moved to a position closer to the center of the projection plane to make it easier to see the part. Moreover, this operation is performed on the original 2 placed on the original platen 3.
Easy and, without moving the hand to adjust the position
Can be done quickly. In particular, when the enlarged zoom is performed, by rotating the two-dimensional CCD 13 while the enlarged zoom is being performed, all the portions of the image can be reliably projected onto the projection surface without any trouble.

In this embodiment, since the rotating mechanism 15 has a structure in which the two-dimensional CCD 13 is swung in the horizontal and vertical directions, the rotating mechanism 15 can be installed in a small space. Even if such a rotating mechanism 15 is provided in the housing 1, the overhead projector can be downsized.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. FIG. 4 shows an optical system that separates and combines visible light in an overhead projector that can perform color projection. The point that a two-dimensional CCD attached to the rotation mechanism is provided is the same as in the first embodiment. Only the visible light of the light emitted from the projection light source 9 is transmitted by the cold mirror 10, and the transmitted visible light passes through the integrator lenses 25 and 26 to become a light beam having a plurality of focal points. And blue and green light. The decomposed red light is reflected by the cold mirror 28, converted into parallel light by the condenser lens 29, enters the polarizing plate 30, passes through the LCD 31, is reflected by the dichroic prism 32, and is projected from the projection lens 12. Projected onto the surface.

The blue / green light separated by the dichroic mirror 27 is separated into blue light and green light by the dichroic mirror 33, and the green light is converted by the condenser lens 29.
Are incident on the polarizing plate 30, pass through the LCD 31, are reflected by the dichroic prism 32, and are projected from the projection lens 12 onto the projection surface. The blue light passes through the correction lenses 34 and 35, is reflected by the total reflection mirrors 36 and 37, and is converted into parallel light by the condenser lens 29.
The light enters the polarizing plate 30, passes through the LCD 31, is reflected by the dichroic prism 32, and is projected from the projection lens 12 onto a projection surface. Therefore, the light transmitted through the LCD 31 on which the image corresponding to each color is displayed is synthesized by the dichroic prism 32, so that a color image is projected on the projection surface. Since the red light, the green light, and the blue light have different optical path lengths, the difference in the optical path length is corrected by the correction lens 3.
It is corrected by 4, 35.

[0022]

According to the first aspect of the present invention, there is provided an overhead projector for rotating an image sensor for reading an image of a document placed on a document table around an X axis and a Y axis orthogonal to each other. Since an operation unit for driving the rotation mechanism is provided, the reading position of the document by the imaging element can be moved by driving the rotation mechanism to rotate the image sensor around the X axis and the Y axis. Therefore, when the projected image falls on the lower edge of the projection surface and becomes difficult to see, or when the image deviates from the projection surface due to the enlarged zoom, the rotating mechanism is driven to drive the image pickup device. By moving the reading position, the portion to be projected can be moved to a position closer to the center of the projection surface to make it easier to see, and the movement of the projection position is complicated by moving the image placed on the document table by hand. work Easy without, and can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic structure of a first embodiment of the present invention.

FIG. 2 is an enlarged side view showing a structure of a rotating mechanism.

FIG. 3 is an enlarged plan view showing the structure of the rotating mechanism.

FIG. 4 is an explanatory diagram showing an optical system according to a second embodiment of the present invention.

FIG. 5 is a side view showing a schematic structure of a conventional example.

[Explanation of symbols]

 2 Document 3 Document table 7 Signal processing unit 8 Display unit 13 Image sensor 15 Rotation mechanism

Claims (1)

[Claims] An image of a document placed on a platen is read by an image sensor, and an image signal output from the image sensor is converted into a display drive signal by a signal processing unit, and an image corresponding to the display drive signal is converted. Is displayed on a display unit, and an image displayed on the display unit is projected toward a projection plane.
An overhead projector, comprising: a rotating mechanism for rotating around a shaft; and an operation unit for driving the rotating mechanism.