JPH0719028B2 - Overhead Projector - Google Patents

Description

The present invention relates to an overhead projector capable of projecting and displaying a digital image based on digital image data stored in a memory.

[Prior art] As a device for projecting materials for presentation meetings on a screen,
There is an overhead projector (hereinafter called OHP). Compared with slides, OHP has the advantages that it is easier to create materials, can be used while directly pointing or adding an original, and has a brighter screen than ordinary slide projectors.

However, in the conventional OHP, basically, characters and figures are written in advance on a transparent sheet by using a marker or the like to create a material, and a plurality of sheets are arranged in the order of explanation and sequentially displayed while being exchanged. There is. For this reason, when the number of sheets used is large, the sheet organization is complicated,
There is also a problem that it is difficult to select a specific sheet by random access.

In order to solve such a problem, in JP-A-60-3616, JP-A-60-213935, and JP-A-61-223726, a liquid crystal display for displaying digital image data is disclosed in OHP. It is disclosed that it is provided between a light source and a screen to project image data on the screen.

[Problems to be solved by the invention]

However, in these OHP devices, a liquid crystal display was simply provided instead of the OHP film, and the Bresenter had to rely on the memory at the time of creating the image data as to which screen was projected next. .

The present invention has been made in view of such conventional problems, and digitizes the OHP material in accordance with the direction of digital commonization of office information, and what kind of image is next projected on the screen. The purpose is to provide an OHP that can be checked in advance.

[Means for solving problems]

To achieve this object, an overhead projector of the present invention includes a display device that displays digital image data in an image file as a still image, and a projection optical system that projects the still image displayed on the display device onto a screen. The above-mentioned overhead projector is characterized in that the projector main body is provided with an auxiliary display device for displaying image data to be displayed next on the display device.

[Action]

According to the present invention, in the conventional OHP, the glass plate portion for placing the original document on the flat lens that focuses the illumination light is a display device including a two-dimensional optical shutter element array such as a liquid crystal display. This makes the display device act as a conventional OHP sheet. Then, the digitized presentation material stored in advance in the image file, that is, the digital image data is retrieved, the digital image data is supplied to the display device, and the presentation material is displayed on the display device. An optical image formed by the illumination light from the projector is enlarged and projected on a screen or the like by a projection mechanism. This allows
It becomes possible to digitize OHP materials. Further, the image data to be displayed next is displayed on the auxiliary display device provided in the main body of the projector so that the content and order of the presentation material can be confirmed.

〔Example〕

Hereinafter, the present invention will be specifically described based on the embodiments shown in the drawings.

FIG. 1 shows the appearance of an embodiment of the present invention.

In the figure, reference numeral 1 denotes a projector main body, and on the upper surface of the projector main body 1, a transmissive display device 2 having a two-dimensional structure including an optical shutter element array and the like is arranged. A light source 13 and a plane lens 11 (see FIG. 2) are arranged on the back surface of the display device 2 so that the convergent light 3 transmitted through the display device 2 is a conventional light source.
Similar to the OHP, the image of the display device 2 is projected on the screen 5 by the projection mechanism 4 including the projection lens 4a and the reflecting mirror 4b.

In addition, the operation panel 6 provided on the front inclined portion of the projector body 1 has three auxiliary display devices 7a, 7b, 7
c, an operation switch 8 and the like are provided. Further, a memory medium storage unit 9 such as a floppy disk device, which functions as an image file described later, is provided on the front surface of the projector body 1.

FIG. 2 shows the optical mechanism.

In the figure, reference numeral 10 denotes a two-dimensional optical shutter element array that constitutes the display device 2, and a plane lens such as a Fresnel lens is arranged in parallel with the optical shutter element array 10 interposed therebetween.
11 and a transparent member for protection, for example, a glass plate 12 are arranged. Then, the light 14 from the light source 13 reaches the plane lens 11 directly or indirectly via the back mirror 15. Then light 14
Is refracted by the plane lens 11 to become convergent light, which is applied to the optical shutter element array 10.

The optical shutter element array 10 includes, for example, a liquid crystal panel using nematic liquid crystal, in which electrodes corresponding to 640 pixels × 480 pixels are formed in a matrix, and a polarizer and an analyzer are arranged on both surfaces of the liquid crystal panel. There is. And
By supplying digital image data from the control circuit 16 to each electrode corresponding to each pixel, the liquid crystal is made optically transparent or opaque for each pixel to control the transmission and blocking of light. In the figure, the hatched portion indicates the light shielding portion.

The convergent light 3 that has passed through the optical shutter element array 10 enters the projection lens 4a of the projection mechanism 4, and is then projected by the reflecting mirror 4b in the direction of the screen 5 (see FIG. 1).
At this time, the projection lens 4a is the optical shutter element array.
An adjustment mechanism (not shown) adjusts the image in 10 in the height direction so that the image is formed on the screen 5. At this time, since the glass plate 12 is within the image forming range of the projection lens 4a, by adding a character or a picture on the glass plate 12 with a water-based marker or the like, it is possible to perform the same on-the-spot as in the conventional OHP. It becomes possible to add and the image of the optical shutter element array 10 is superimposed and projected on the screen 5.

Next, FIG. 3 shows the flow of digital image data.

When an image to be displayed is specified by the operation switch 8 provided on the operation panel 6, an image file is generated by a signal from the interface 21 connected to the operation switch 8.
For example, digital image data in a floppy disk device built in the projector body 1 is searched, and the searched image data is loaded into the image memory 22 such as a semiconductor memory. In the case of this embodiment, the image memory 22 has a capacity to store information for four images.

Next, the following functions are selected by an instruction from the operation panel 6.

The digital image data loaded in the image memory 22 is displayed as it is. That is, the optical shutter element array 10 is controlled by the reduction / magnification control device 23 based on the digital image data for one sheet in the image memory 22. In this case, by loading four pieces of digital image data in the image memory 22 in the order of display in advance, it is possible to save access and loading time. At this time, the four pieces of digital image data in the image memory 22 to be displayed next are sequentially displayed on the above three auxiliary display devices 7a, 7b, 7c.

The digital image data in the image memory 22 is displayed after being subjected to image editing such as enlargement, reduction, magnification, and image shift. That is, as shown in FIG. 4A, with respect to the original image data 100, demagnified image data as shown by 110, enlarged image data as shown by 120, and shifted image data as shown by 130 are obtained. . When expanding, for example,
The digital image data may be padded and displayed by reading the data at the same address in the image memory 22 a plurality of times. In this case, the character "ABC" shown by the broken line indicates a part that is not displayed. On the contrary, when the reduction is performed, for example, the digital image data in the image memory 22 may be thinned out and read and displayed. It should be noted that the bias magnification means that the vertical and horizontal ratios of enlargement and reduction are different.

Digital image data for multiple images are displayed in parallel and superimposed. That is, as shown in FIG. 4B, the two original image data 200, 21 stored in the image memory 22 are stored.
For 0, partial parallel image data such as 220, 230
The reduced parallel image data in which two or more images are reduced and displayed side by side are obtained. In addition, as shown in FIG. 4 (c), the two original image data 300, 310 are overlapped 320
It is also possible to create synthetic image data as shown in.

The image file 20 has a capacity of 1 MB, for example.
When a 3.5 inch floppy disk is used, the number of displayable pixels on the display device 2 is 640 pixels x 4 in binary display.
Assuming 80 pixels, about 25 images can be stored. If an index is added to each image, this index will be searched according to an instruction from the operation panel 6, and the image file will be serially or randomly generated.
You can access the desired digital image data in 20.

As the above-described image reduction / enlargement method, various methods such as thinning, padding, and interpolation by averaging are known as described above, and hardware for realizing those methods is known. As for the above, various means such as reading by a counter based on the enlargement ratio have been proposed, and therefore detailed description thereof will be omitted here.

When an existing manuscript is input to the image file 20 such as a floppy disk as digital image data, the manuscript is digitally input by an image input device 24 having the same structure as that of a facsimile or a digital copying machine as shown in FIG. Digital information can be obtained by converting it to image data. Further, a material is created using the workstation 25 having a document creating function and a graphic creating function, and this is transferred to the image file 20 to be digital image data,
This can also be displayed directly on the OHP26. in this case,
Since it is not necessary to print out the material once at the workstation 25, the material creation work is rationalized.

In the above-described embodiments, the optical shutter element array is taken as an example of the display device, but in addition to this, a high brightness CRT (cathode ray tube) that also serves as a light source, an LED (light emitting diode) display, or the like may be used. It is possible.

Further, in the example shown in FIG. 5, the image file 20 such as a floppy disk is used as one of the image data link terminals, but the data is directly received without using the floppy disk, or both are arranged in parallel. Is also possible.

〔The invention's effect〕

As described above, in the present invention, a display device such as an optical shutter element array that displays digital image data of an image file as a still image is used as an OHP image source. Since this display device is digitally image-processed, it is easy to handle or search OHP images. Further, it is possible to instantly enlarge or reduce the image by digital processing, and at the presentation conference or the like, the optimum material can be displayed in an appropriate state according to the content of the explanation, so that the effect of the presentation can be enhanced. In addition to this, since the auxiliary display device is provided in the display body, it is possible to check the screen to be displayed next, and the confusion that the image different from the image content that the presenter thought was displayed is eliminated, The presentation effect can be enhanced. Further, since the image is processed as digital image data, there is an effect that it corresponds to the digitization of the office information and the material created by the workstation can be input without printing out.

[Brief description of drawings]

FIG. 1 is an external view of an OHP according to an embodiment of the present invention, FIG. 2 is a schematic diagram for explaining the optical system of the OHP, FIG. 3 is a block diagram showing the flow of digital image data, and FIG. 4 is digital image processing. And FIG. 5 is a block diagram showing a method of creating digital image data. 1: Projector body, 2: Display device 3: Convergent light, 4: Projection mechanism 4a: Projection lens, 4b: Reflector 5: Screen, 6: Operation panel 7a, 7b, 7c: Auxiliary display device 8: Operation switch, 9 : Memory medium storage 10: Optical shutter element array, 11: Flat lens 12: Glass plate, 13: Light source 14: Light, 15: Rear mirror

Claims (1)

[Claims] 1. An overhead projector provided with a display device for displaying digital image data in an image file as a still image, and a projection optical system for projecting the still image displayed on the display device onto a screen. An overhead projector, further comprising an auxiliary display device for displaying image data to be displayed on the display device next.