JPH1020396A - Overhead projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To project an original and a hand-written pattern in a superposed state. SOLUTION: The contents of the original is displayed on a liquid crystal panel 10 by imaging the original 1 by an image pickup element 5. The hand written pattern is displayed on the liquid crystal panel 12 by converting the pattern plotted on a touch panel 17 to an image signal by a signal processing part 19. Blue light in light emitted from a lamp 7 is reflected by a dichroic mirror 9, and light other than the blue light is transmitted through the mirror 9, then, the light other than blue light is made incident on a liquid crystal panel 10, and the blue light is made incident on a liquid crystal panel 12. Light beams separately transmitted through the liquid crystal panels 10 and 12 are synthesized by a dichroic mirror 14, then, the synthesized light is projected on a screen through a projecting lens 16. The original 1 and the hand-written pattern are projected in a superposed state in such a way.

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 document as it is.

[0002]

2. Description of the Related Art Recently, an overhead projector (hereinafter, referred to as OHP), which is capable of enlarging and projecting an opaque document as it is without using a conventional transparent sheet, as a presentation device used for a conference or a lecture at a university. (For example, Japanese Patent Application Laid-Open No. 7-1047)
No. 13). In this technique, a document is imaged by a TV camera, and the imaged content is projected on a screen by a projection display device.

In this OHP, an image is taken by illuminating a document surface of a document set face down on a document mounting glass with illumination inside the OHP. Such a configuration is employed because an image can be captured without being affected by external light. By the way, in a lecture or the like of a university, a presenter sometimes makes a presentation while writing characters or figures on a manuscript. However, in the above-described OHP, in order to turn the material side of the original face down, while writing characters and figures on the original,
It is not possible to project at the same time. In addition, if it is desired to project a non-written document again after writing and projecting characters and graphics on the document, a new document without writing must be newly created.

[0004]

As described above, the OHP capable of projecting an opaque original as it is has a problem that the original and the handwritten content cannot be projected in an overlapping manner. SUMMARY An advantage of some aspects of the invention is to provide an OHP capable of projecting a document on a desired content in a superimposed manner.

[0005]

According to a first aspect of the present invention, there is provided an image pickup means for reading an original, and a first means for converting an image signal output from the image pickup means into a liquid crystal drive signal.
, A lamp as a light source, a first dichroic mirror that reflects predetermined color light out of light from the lamp and transmits light other than the predetermined color light, and is arranged so that light other than the predetermined color light is incident. A first liquid crystal panel for performing display based on a liquid crystal drive signal from the first driving means, a pattern input means for inputting a handwritten pattern to be projected on a document, and an output from the pattern input means. Second driving means for converting an image signal into a liquid crystal driving signal;
A second liquid crystal panel arranged to receive predetermined color light from the first dichroic mirror and performing display based on a liquid crystal driving signal from a second driving unit; and a light transmitted through the second liquid crystal panel. It is provided with a second dichroic mirror that reflects and transmits light transmitted through the first liquid crystal panel and combines them, and a projection lens that projects light from the second dichroic mirror onto a screen. In this way, the image of the original is imaged by the imaging means, the contents of the original are displayed on the first liquid crystal panel, and the drawn handwritten pattern is converted into an image signal by the pattern input means, whereby the handwritten pattern is converted. It is displayed on the second liquid crystal panel. On the other hand, the first dichroic mirror reflects predetermined color light out of the light emitted from the lamp and transmits light other than the predetermined color light, and the light other than the predetermined color light enters the first liquid crystal panel, and the predetermined color light is emitted. The light enters the second liquid crystal panel. Then, the second dichroic mirror combines the transmitted light of the first and second liquid crystal panels, and the projection lens projects the light on the screen.

Further, the present invention further comprises a third liquid crystal panel for performing display based on a liquid crystal drive signal from the first driving means, and the pattern input means includes a third liquid crystal panel. It is provided on the display surface and has a light transmitting property for transmitting light from the third liquid crystal panel. By providing the light-transmissive pattern input means on the display surface of the third liquid crystal panel, the contents of the document can be viewed through the pattern input means.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

1. Embodiment 1. FIG. 1 is a block diagram of an OHP according to the first embodiment of the present invention. First, the operation of the OHP when the overlapping display is not performed will be described. First, this OHP
The user sets the original 1 on the original glass 2 face down. The lower surface of the set document 1 is illuminated by a document light 3 such as a fluorescent lamp. The total reflection mirror 4 reflects light from the document 1 and causes the light to enter the image sensor 5.

The image pickup device 5 photoelectrically converts incident optical information and outputs an image signal.
Is converted into a liquid crystal drive signal and output to the transmissive liquid crystal panel 10. Thus, the contents of the document 1 are displayed on the first liquid crystal panel 10. On the other hand, the light emitted from the lamp 7 is
To the dichroic mirror 9. The cold mirror 8 transmits harmful infrared rays and reflects only visible light.

The dichroic mirror 9 reflects only blue light, which is a predetermined color light, out of the visible light emitted from the lamp 7 and reflected by the cold mirror 8. Here, since no superimposed display is performed, nothing is displayed on the liquid crystal panel 12 described later. Therefore, the dichroic mirror 9
The blue light reflected by is transmitted through the liquid crystal panel 12 as it is and enters the total reflection mirror 13. The total reflection mirror 13 reflects the blue light and guides the blue light to the second dichroic mirror 14.

At the same time, the dichroic mirror 9 transmits light other than blue light from the cold mirror 8 and makes the light enter the liquid crystal panel 10. Then, the total reflection mirror 11 reflects the light passing through the liquid crystal panel 10 and makes the light enter the dichroic mirror 14. At this time, since the contents of the original 1 are displayed on the liquid crystal panel 10, of the light from the dichroic mirror 9, light incident on a black portion in the original, that is, a portion where characters and figures are displayed is blocked. Then, only light incident on a white background portion, that is, a non-display portion in the document passes.

Next, the dichroic mirror 14 reflects the blue light from the total reflection mirror 13 and
These lights are combined by transmitting light from the light source. Therefore, since the light from the total reflection mirror 11 is light excluding blue light (yellow light), the black portion of the document becomes blue light and the white portion of the document becomes the original white light of the lamp 7 by being combined. . Then, the total reflection mirror 15 reflects this light and the projection lens 16 projects.

In this manner, an original with blue characters and figures and a white background is projected on a screen (not shown). Therefore, if this OHP is used, the original 1 can be directly projected on an enlarged scale, and there is no need to copy the original onto a transparent film.

Next, the operation of the OHP when performing superimposed display will be described. The OHP includes a document cover having a function of holding down the original 1 and shielding light when the original 1 is smaller than the reading surface of the original glass 2. Then, this material cover is a cover 21 which becomes an outer cover when closed.
And a cover 22 serving as an inner cover.
These are attached to the housing of the OHP main body by hinges 23, and are rotatably supported around the axis of the hinge 23 as shown by a two-dot chain line in FIG.

A touch panel 17 is provided on the back side of the material cover 21. A user of the OHP opens the cover 21 so that the touch panel 17 faces upward as shown in FIG. 1 and presses the touch panel 17 from above with a fingertip or a writing instrument to draw a pattern such as a character or a figure. In response to this, the touch panel coordinate value detection unit 18 sequentially detects the positions on the touch panel where the fingertip or the writing implement has contacted,
A position coordinate signal indicating the detected position is output.

The signal processing section 19 receives the position coordinate signals output from the coordinate value detecting section 18 one after another, and
7, image signals for all the detection areas are generated. This image signal is converted into a liquid crystal drive signal by the drive unit 20 and output to the transmissive liquid crystal panel 12. Thereby, a handwritten pattern such as a character or a figure drawn by the user is displayed on the second liquid crystal panel 12. With the display on the liquid crystal panel 12, of the blue light from the dichroic mirror 9, light incident on the portion where the handwritten pattern is displayed is blocked, and only light incident on the non-display portion passes.

Therefore, the blue light from the total reflection mirror 13 incident on the dichroic mirror 14
Only the light that has entered the non-display portion of the original 1. This light and the yellow light from the total reflection mirror 11 are combined by the dichroic mirror 14 as described above. Is yellow light, and the white background portion of the document 1 excluding the handwritten pattern is white light. In this way, the original 1 having a blue character and a graphic and a white background and a yellow handwritten pattern are projected on a screen (not shown) in a superimposed manner.

Embodiment 2 In the first embodiment, the touch panel 17 is used as the pattern input means, but an electronic blackboard type pattern input means may be used. FIG. 2 is a block diagram of an OHP showing another embodiment of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. Also in the present embodiment, the material covers are the covers 21a,
2 which are hinged to the housing of the OHP body.
Is the same as in the first embodiment.

In this embodiment, an electronic blackboard is provided on the back side of the material cover 21a. The electronic blackboard includes a whiteboard 24 and a reading unit 25 that moves on the rail (not shown) provided on the document cover 21a in the left-right direction in FIG. The reading unit 25 is provided with an image sensor 26 in which pixels are arranged in a straight line in a predetermined direction (here, a direction perpendicular to the plane of FIG. 2), and a reading light source (not shown). .

As in the first embodiment, the OHP user operates the cover 21a so that the white board 24 faces upward.
Is opened, and patterns such as characters and figures are written on the whiteboard 24 with a writing instrument such as a felt pen. After the drawing is completed, the reading unit 25 moves to the left in FIG. The light of the light source for reading is irradiated on the whiteboard 24, and the reflected light is incident on the image sensor 26. The image sensor 26 photoelectrically converts the incident light information and outputs an electric signal to the signal processing unit 19a. I do.

By performing such image capturing while moving the reading section 25 to the left in FIG. 2, the signal processing section 19a generates image signals for the entire drawing area of the whiteboard 24 and drives them. Output to the unit 20. Subsequent operations are the same as those in the first embodiment. Thus, the same effect as in the first embodiment can be obtained. In the present embodiment, the electronic blackboard is of the type in which the reading unit 25 moves, but it goes without saying that the electronic blackboard of the type in which the whiteboard 24 moves may be used.

Embodiment 3 FIG. 3 is a block diagram of an OHP showing another embodiment of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. Also in the present embodiment, the material cover includes the covers 21b and 22. On the back side of the document cover 21b, a third liquid crystal panel 27 with a backlight,
Transparent touch panel 1 installed in close contact with the display surface of 7
7a.

As in the first embodiment, the original glass 2
When the original 1 is set upside down, the contents of the original 1 are displayed on the liquid crystal panel 10. At this time, the liquid crystal driving signal from the drive unit 6 is also supplied to the liquid crystal panel 27. As a result, the contents of the original 1 are displayed not only on the liquid crystal panel 10 but also on the liquid crystal panel 27. The user of the OHP presses the transparent touch panel 17a from above with a fingertip or a writing tool to draw a pattern such as a character or a figure while watching the screen of the liquid crystal panel 27 displayed through the transparent touch panel 17a.

In response to this, the touch panel coordinate value detecting section 18 successively detects the positions on the touch panel where the fingertip or the writing implement has contacted, and outputs a position coordinate signal indicating the detected position. Subsequent operations are the same as those in the first embodiment. Therefore, by providing the transparent touch panel 17a, which is a light-transmissive pattern input means, on the third liquid crystal panel 27, the user touches the transparent touch panel 17a while watching the contents of the document 1 displayed on the liquid crystal panel 27, and
Can be written, so that the usability can be greatly improved as compared with the first and second embodiments.

In the first to third embodiments, the pattern input means is provided on the document cover. However, as shown in FIG. 4, the board 30 provided with the pattern input means may be pulled out from the OHP housing. However, it may be separate from the main body of the OHP. In addition, in the first to third embodiments, the dichroic mirrors 9 and 14 are described as reflecting the blue light as the predetermined color light. However, the predetermined color light may be other than the blue light. It is possible to project the original 1 in which the characters and figures are green and the background is white and the handwritten pattern of magenta (purple), and the combination of these can be set as appropriate by changing the light of the predetermined color.

Further, the density of the image signal may be inverted by the first driving unit 6. In this case, only the characters and figures pass through the liquid crystal panel 10, so that the characters and figures are white and the background is blue. Original 1 and a black (that is, no light is projected) pattern can be projected.

[0026]

According to the present invention, the contents of the original are displayed on the first liquid crystal panel, the input handwritten pattern is displayed on the second liquid crystal panel, and the first light to which light other than the predetermined color light enters is displayed. By combining the transmitted light of the liquid crystal panel and the transmitted light of the second liquid crystal panel on which the predetermined color light is incident, the original and the handwritten pattern can be projected in different colors so that the handwritten pattern is input while This can be superimposed on the original and projected simultaneously. Therefore, it is not necessary to directly write the handwritten pattern on the original, and the same original can be used repeatedly.

Further, by providing the light-transmissive pattern input means on the display surface of the third liquid crystal panel for displaying the contents of the document, the contents of the document can be viewed through the pattern input means, so that the usability is further improved. Can be done.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of an OHP showing another embodiment of the present invention.

FIG. 3 is a block diagram of an OHP showing another embodiment of the present invention.

FIG. 4 is an external view of an OHP showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Original document, 5 ... Image sensor, 6, 20 ... Drive part, 7 ... Lamp, 9, 14 ... Dichroic mirror, 10, 12, 2
7: Liquid crystal panel, 16: Projection lens, 17, 17a: Touch panel, 18: Coordinate value detection unit, 19, 19a: Signal processing unit, 24: White board, 25: Reading unit.

Claims (2)

[Claims] 1. An image pickup means for reading an original, a first drive means for converting an image signal output from the image pickup means into a liquid crystal drive signal, a lamp as a light source, and a predetermined color light of light from the lamp A first dichroic mirror that reflects light other than the predetermined color light and transmits the light other than the predetermined color light;
A first liquid crystal panel for performing display based on a liquid crystal driving signal from the driving means, a pattern input means for inputting a handwritten pattern to be projected on the original, and an image signal output from the pattern input means A second driving means for converting the light into a liquid crystal driving signal; and a second driving means arranged to receive a predetermined color light from the first dichroic mirror and performing display based on the liquid crystal driving signal from the second driving means. A second liquid crystal panel that reflects light transmitted through the second liquid crystal panel and transmits light transmitted through the first liquid crystal panel to combine them;
And a projection lens for projecting light from the second dichroic mirror onto a screen, and projecting the document and the handwritten pattern in a superimposed manner. 2. The overhead projector according to claim 1, further comprising: a third liquid crystal panel that performs display based on a liquid crystal drive signal from the first drive unit, wherein the pattern input unit includes the third liquid crystal panel. An overhead projector which is provided on a display surface of the panel and has a light transmitting property for transmitting light from a third liquid crystal panel.