JPH07175032A - Overhead projector - Google Patents

Abstract

PURPOSE:To enlarge and project an original as it is and to project the whole area of the original whichever it may be the horizontally written original or the vertically written original. CONSTITUTION:The image of the original 1 is picked up by an image pickup element 5 and converted into an image signal. In a first projection mode, the image signal is converted into a liquid crystal driving signal as it is by a signal processing part 6. Then, the light of a lamp 7 transmitted through a liquid crystal panel 8 is reflected on a mirror 9. Besides, the light of the mirror 9 passed through a lens 10 is reflected on a mirror 11 and projected on a screen 20 by a projection lens 12. In a second projection mode, the image signal is converted into the liquid crystal driving signal for projecting the original 1 whose left and right are inverted by the processing part 6. Then, the mirror 11 is rotated with the optical axis of the incident light from the lens 10 as the center. Besides, the reflected light from the mirror 11 made to pass the lens 12 rotated together with the mirror 11 is reflected on a mirror 13 and projected on the screen 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead projector, and more particularly to an overhead projector capable of enlarging and projecting an opaque original as it is.

[0002]

2. Description of the Related Art Conventionally, there is an overhead projector (hereinafter referred to as OHP) which projects light onto a transparent film from below, for example, and projects it onto a screen or the like by a projection lens and a mirror. In such an OHP, an original is once copied onto a transparent film for OHP, and the original is enlarged and projected by irradiating the transparent film with light from a lamp. There is also a type called a reflection type, in which strong light is applied to a document and the reflected light is projected by a lens.

In order to correctly project an original set on the original table with these OHPs, it is necessary to change the orientation of the original depending on whether the original is written vertically or horizontally. However, for example, in the case of an OHP in which an original document described below in which the longitudinal direction of an A4 size sheet is left and right (hereinafter, referred to as horizontal writing) is standard,
If an attempt is made to project an original document in which the longitudinal direction of the size is up and down (hereinafter referred to as vertical writing), a part of the original document will be protruded from the document table and trimmed.

[0004]

Since the conventional OHP projects the original document as described above, it is necessary to copy an opaque original document such as plain paper onto a transparent film. The reflection type OHP used as it is has a problem that it is difficult to see in a bright place because the amount of light is not sufficient because it is projected by the reflected light from the original.
Further, in both OHPs, it is necessary to change the orientation of the original depending on whether the original is written vertically or horizontally. However, in either the vertical writing or the horizontal writing, the original protrudes from the original table and the entire original cannot be projected. was there. In order to solve the above problems, an object of the present invention is to provide an overhead projector capable of correctly projecting a document regardless of whether the document is vertically or horizontally written without having to copy the document onto a transparent film. .

[0005]

SUMMARY OF THE INVENTION According to the present invention, an image pickup device for reading an original and an image signal output from the image pickup device are directly converted into a liquid crystal drive signal in the first projection mode, and the second projection is performed. In the mode, a signal processing unit that converts the left and right of the original into a liquid crystal drive signal, a lamp that is a light source, a liquid crystal panel that is arranged so that light from the lamp is incident and that performs display based on the liquid crystal drive signal, A first mirror that reflects the transmitted light of the liquid crystal panel toward the screen in the first projection mode, and rotates about the optical axis on which the transmitted light is incident and reflects the transmitted light in the second projection mode. Is arranged so that the light from the first mirror is incident, the light from the first mirror is projected onto the screen in the first projection mode, and the first light is projected in the second projection mode.
It has a projection lens that rotates around the optical axis as the mirror rotates, and a second mirror that reflects the light from the projection lens and projects it on the screen in the second projection mode.

[0006]

According to the present invention, a document is imaged by the image pickup device and converted into an image signal. In the first projection mode, the signal processing unit converts the image signal as it is into the liquid crystal drive signal and outputs it to the liquid crystal panel, and the first mirror reflects the light emitted from the lamp and transmitted through the liquid crystal panel in the screen direction. The projection lens projects this reflected light on the screen.
In the second projection mode, the signal processing unit converts the image signal into a liquid crystal drive signal in which the left and right sides of the original are inverted, and the first mirror rotates about the optical axis on which the transmitted light of the liquid crystal panel is incident. The transmitted light of the lever is reflected. Then, the reflected light of the first mirror that has passed through the projection lens rotated together with the first mirror is reflected by the second mirror and projected on the screen.

[0007]

1 is a block diagram of an OHP showing an embodiment of the present invention, and FIG. 2 is a view showing the appearance of the OHP. Figure 1
In FIG. 1, 1 is an original, 2 is original glass for setting the original 1, 3 is original illumination such as a fluorescent lamp for illuminating the original 1, 4 is a total reflection mirror for reflecting light from the original 1 in the entire visible region, Reference numeral 5 denotes an image sensor that converts the incident light from the total reflection mirror 4 into an image signal, and 6 converts the image signal output from the image sensor 5 into a liquid crystal drive signal as it is in the first projection mode, and a second signal. In the projection mode, the signal processing unit converts the left and right of the document into a liquid crystal drive signal.

Reference numeral 7 is a lamp which is a light source for projection, and 8
Is a liquid crystal panel that performs display based on a liquid crystal drive signal, 9 is a total reflection mirror that reflects light that has passed through the liquid crystal panel 8 over the entire visible range, and 10 is a lens. Reference numeral 11 denotes a total reflection mirror which is a first mirror. In the first projection mode, the light reflected by the total reflection mirror 9 and passing through the lens 10 is reflected in the screen direction, and in the second projection mode. It rotates around the optical axis of the incident light that has passed through the lens 10 to reflect this light.

A projection lens 12 is arranged so that the light from the total reflection mirror 11 is incident thereon. In the first projection mode, the light from the total reflection mirror 11 is projected onto the screen, and the second Total reflection mirror 1 in the projection mode
With the rotation of 1, it rotates together with the total reflection mirror 11. 1
Reference numeral 3 is a total reflection mirror that is a second mirror that reflects the light from the projection lens 12 and projects it onto the screen in the second projection mode, and 20 is the screen.

In FIG. 2, a total reflection mirror 11 and a projection lens 12 are housed inside, and a total reflection mirror 1 is provided.
A projection head 15 having a rotating mechanism (not shown) rotatable about an optical axis incident on 1 is a casing of this OHP.

FIG. 1A shows a first projection mode which is a standard projection mode.
In the projection mode of, for example, the original 1 in which the horizontal writing "P" is written in the OHP standardized by the horizontal writing.
Shows the operation of projecting. In addition, FIG.
Only the projection part in the OHP of (a) is shown,
In the projection mode, for example, the operation of projecting the original 1 in which the vertically written “P” is written in this OHP. 2A and 2B show the appearance of the OHP in the first and second projection modes, respectively.

Next, the operation of such an OHP will be described for the first projection mode. First, as shown in FIG. 2A, the original 1 on which the horizontal “P” is written is set face down on the original glass 2. The lower surface of the set document 1 is illuminated by the document illumination 3. And the total reflection mirror 4
Is configured to reflect the light from the original 1 and make it enter the image pickup device 5.

Next, the contents of the original 1 are picked up by the image pickup device 5 and converted into image signals. The image signal output from the image sensor 5 is converted into a liquid crystal drive signal by the signal processing unit 6 and output to the liquid crystal panel 8. Thus, the content of the original 1 is displayed on the liquid crystal panel 8 as shown in FIG.

On the other hand, the light emitted from the lamp 7 which is the light source is incident on the liquid crystal panel 8, and the light transmitted through the liquid crystal panel 8 is reflected by the total reflection mirror 9. The reflected light of the total reflection mirror 9 passes through the lens 10 and then enters the total reflection mirror 11. At this time, the image reflected on the total reflection mirror 11 is an image in which the left and right of the document 1 are reversed as seen from the direction of the screen 20 as shown in FIG.

Then, the projection lens 12 projects the reflected light of the total reflection mirror 11 onto the screen 20, so that the content "P" of the original 1 is projected onto the screen (FIG. 1).
In (a), the back surface of the screen 20 is shown, and therefore the display is left-right reversed. Therefore, the original 1 can be enlarged and projected as it is, and it is not necessary to copy it on the transparent film.

Next, a second projection mode for projecting the original 1 written in a direction different from that of the original 1 in the first projection mode (vertical writing in this example) will be described. When in the second projection mode, the signal processing unit 6 causes the image sensor 5
The image signal output from the above is converted into a liquid crystal drive signal in which the left and right of the original 1 are inverted. Therefore, as shown in FIG.
When a document 1 in which a vertical “P” is written as shown in (b) is set, the image displayed on the liquid crystal panel 8 is as shown in FIG.
As shown in (b), the content of "P" is reversed left and right.

Then, as in the case of the first projection mode, the light which has passed through the lens 10 is incident on the total reflection mirror 11, and at this time, the total reflection mirror 11 and the projection lens 12 are
By a rotation mechanism (not shown) of the projection head 14 that houses them, the projection head 14 is rotated about the optical axis incident on the total reflection mirror 11 and is oriented in a direction perpendicular to the screen 20.

Therefore, when viewed from the direction of the total reflection mirror 13, the image reflected on the total reflection mirror 11 is an image rotated by 90 ° with respect to the original 1 of FIG. 2 (b) as shown in FIG. 1 (b). There is. Then, the projection lens 12 projects the reflected light of the total reflection mirror 11 onto the total reflection mirror 13 attached to the OHP casing 15 by a supporting mechanism (not shown), and the total reflection mirror 13 projects this light onto the screen 20. . Thus
In the second projection mode, the manuscript 1 in which the vertically written "P" is written
Can be correctly projected and it is not necessary to change the orientation of the original document 1. Therefore, the original document 1 can project the entire area of the original document 1 without protruding from the original document glass 2.

In the optical system of this embodiment, which includes the liquid crystal panel 8 to the total reflection mirror 9 to the lens 10 to the total reflection mirror 11, if the desired image is displayed on the screen 20, for example, the total reflection mirror 9 is used. It may be a non-configuration, or another configuration such as a configuration having a plurality of lenses 10. Further, although the black and white original document 1 is projected in the present embodiment, a color original document can also be projected if both the image pickup device 5 and the liquid crystal panel 9 are used for color.

[0020]

According to the present invention, it is not necessary to copy an opaque plain paper original on a transparent film, and the enlarged projection can be performed with high clarity as it is. Also, the first and second
By providing the projection mode of No. 1, it is possible to correctly project whether the original is written vertically or horizontally, and it is not necessary to change the orientation of the original, so that the entire area of the original can be projected. .

[Brief description of drawings]

FIG. 1 is a block diagram of an OHP showing an embodiment of the present invention.

FIG. 2 is a diagram showing an appearance of the OHP shown in FIG.

[Explanation of reference numerals] 1 original 5 image pickup device 6 signal processing unit 7 lamp 8 liquid crystal panel 9 total reflection mirror 10 lens 11 first mirror 12 projection lens 13 second mirror

Claims (1)

[Claims] 1. An image pickup device for reading an original, and an image signal output from the image pickup device is directly converted into a liquid crystal drive signal in the first projection mode, and the left and right sides of the original are changed in the second projection mode. A signal processing unit for converting into an inverted liquid crystal drive signal, a lamp which is a light source, a liquid crystal panel which is arranged so that light from the lamp is incident and performs display based on the liquid crystal drive signal, and a first projection mode When the second projection mode is selected, the transmitted light of the liquid crystal panel is reflected in the direction of the screen, and in the second projection mode, the first mirror rotates about the optical axis on which the transmitted light is incident and reflects the transmitted light. Is arranged so that the light from the mirror of
A projection lens that projects light from the first mirror onto the screen in the first projection mode, and rotates around the optical axis as the first mirror rotates in the second projection mode; An overhead projector comprising: a second mirror that reflects light from a projection lens and projects the light onto a screen in the second projection mode.