JPH0521071Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention enables the projection of a clear enlarged image using a general transmission type overhead projector, even though the area of the original picture is small compared to the area of the stage. The present invention relates to an enlarged projection device for an overhead projector.

(Prior art) In a general transmission type overhead projector (hereinafter referred to as OHP), the stage surface is illuminated with high brightness by a halogen lamp or the like disposed below, and a transparent film or the like is placed on the stage surface. The original picture drawn on the page will be displayed. The light from the stage surface passes through the original image and enters the lens in the head section placed above the stage, and then the optical axis direction is changed by a reflector and is directed onto a screen or wall placed at a distance. The image is enlarged and projected. It takes
OHPs are widely used at conferences, lectures, and various research presentations because they can easily enlarge and project handwritten materials as original images, and also allow writing on the original images on stage during projection.

(Problem to be solved by the invention) By the way, the size of the OHP stage is, for example, 280 x 280 mm. On the other hand, when using slide film, a liquid crystal display that is difficult to enlarge, 35 mm film, etc. as the original image, the area of the original image is too small compared to the area of the stage.
The following problems will occur.

First, even if you increase the magnification of the lens in the head of a conventional general OHP, you will not be able to obtain a sufficient magnification and the image will be projected onto a screen or wall. The image is small and unclear. Moreover, the amount of light that passes through the small area of the original image is only a fraction of the light that illuminates the entire surface of the stage, so if the screen or wall is moved away and the image is enlarged, the amount of light will be insufficient and the projected enlarged image will be becomes dark and indistinct.

Furthermore, the light on unnecessary parts of the stage surface other than where the small original picture is placed is dazzling for the OHP operator, so it is necessary to take measures such as covering unnecessary stage parts with black paper.

The purpose of this invention was made in consideration of the above-mentioned circumstances when projecting a small area original image using a general OHP, and it is possible to clearly obtain an enlarged image of a small original image while using a general OHP. An object of the present invention is to provide an enlarged projection device for an overhead projector.

(Means for Solving the Problem) In order to achieve the above object, the magnifying projection device for an overhead projector of the present invention has an optical axis perpendicular to the stage surface on the stage of a transmission type overhead projector. A predetermined angle θ with respect to this stage surface is placed directly below the head portion having a
A planar image reflection plate is provided at an angle of θ, and the lens light is further directed by the predetermined angle θ in the direction of the inclination of the perpendicular line to the vertical line of the image reflection plate so as to connect the enlarged image to the image reflection plate. A lens means is disposed with its axis tilted, and an enlarged image is further connected to the image reflection plate in a direction in which the optical axis of the lens is inclined with respect to the optical axis of the lens on the opposite side of the image reflection plate on the optical axis of the lens. an original image holding means for holding the original image by tilting a vertical line of the original image as much as necessary to display the original image; further, an irradiation means for irradiating the original image from the opposite side of the lens means; The image connected to the head is enlarged and projected through the head section.

The irradiating means may be configured to condense and reflect the light from the stage surface with one or more light source reflectors to irradiate the original image from the back side.

Further, as the irradiation means, a light source different from the light source that irradiates the stage surface may be provided, and the original image may be directly irradiated from the back side with this light source.

(Function) A sufficient amount of light from the irradiation means passes through the small area of the original image, is enlarged by the lens means, and an enlarged image is formed on the image reflection plate. And the video reflector. Since it is tilted by a predetermined angle θ with respect to the stage surface of the OHP, the enlarged image connected to the image reflection plate is not obstructed by the lens means, etc.
The light enters a lens in the head section located above the OHP and is enlarged and projected.

The light from the stage surface can be effectively utilized by condensing and reflecting the light from the stage surface using one or more light source reflectors to serve as an irradiation means.

Furthermore, if a light source as an irradiation means is provided separately from the light source that irradiates the stage surface, a small original image can be easily irradiated with a desired amount of light and enlarged and projected without turning on the light source that irradiates the stage surface.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a vertical cross-sectional view of the essential parts of the enlarged projection device for an overhead projector of the present invention, FIG. 2 is an external perspective view of FIG. 1, and FIG. FIG. 2 is an external perspective view of the magnifying projection device of the present invention mounted on the screen.

In FIGS. 1 to 3, a stage 2 is provided on the upper surface of an OHP main body 1, and the surface of this stage 2 is illuminated with high brightness from below by a halogen lamp, etc. (not shown) built into the OHP main body 1. Further, above the stage 2, a head section 5 consisting of a lens 3 having an optical axis perpendicular to the stage surface and a reflecting mirror 4 is arranged so as to be vertically adjustable by a focus adjustment member 6 or the like. Note that 7 is an OHP power switch, 8 is a fuse, and 9 is a commercial frequency power cord.

The enlarged projection device 10 for an overhead projector according to the present invention is as shown in FIG.
It is placed to cover stage 2 of the OHP.

This enlarged projection apparatus 10 is configured as follows. First, the lower surface of the casing 11 is opened, and a planar image reflection plate 12 with a chain-like surface is mounted on the stage 2 in a portion of the casing 11 located directly below the head portion 5.
It is arranged so as to be inclined at a predetermined angle θ with respect to the surface. This predetermined angle θ is set to an appropriate angle greater than 0 degrees and less than 45 degrees. Furthermore, the housing 11 has a video output port 13 located above the video reflection plate 12 at the head portion 5.
It is opened towards. In addition, the lens means 14 further tilts the lens optical axis by a predetermined angle θ in the direction of inclination of the vertical line V ₁₂ with respect to the vertical line V ₁₂ of the image reflection plate 12.
The V ₁₄ is tilted and fixed to the housing 11. Then, an image reflection plate 12 is provided for this lens means 14.
An original image holding means 16 for holding an original image 15 is appropriately formed on the lens optical axis line V ₁₄ on the opposite side. This original image holding means 16 holds the vertical line V of the original image ₁₅ by a predetermined angle θ' suitable for further connecting the enlarged image to the image reflection plate 12 in the direction of the inclination of the lens optical axis V ₁₄ with respect to the lens optical axis V 14. Original picture 15 by tilting ₁₅
hold. The original image holding means 16 also has an original image insertion opening 1 that allows the original image 15 to be inserted and taken out from the outside of the housing 11 up to the lens optical axis line V ₁₄ .
7 is opened to communicate with the outer wall of the casing 11. The distance between the lens means 14 and the image reflecting plate 12 and the distance between the lens means 14 and the original image 15 are fixed such that the enlarged image of the original image 15 is connected to the image reflecting plate 12 according to the focal length of the lens means 14. Of course.

Further, one or more light source reflection plates 18 serving as irradiation means are appropriately disposed on the casing 11 so as to condense and reflect the light from the stage 2 surface and irradiate the original image 15 from the back side. It is desirable that the light source reflection plate 18 be able to condense and reflect the light from the stage 2 surface without waste, and to illuminate the original image 15 with a sufficient amount of light. However, if the structure becomes too complicated, the device becomes expensive. Therefore, the light source reflection plate 18 may be appropriately designed in consideration of the amount of light irradiating the original image 15 from the back side and the appropriate price.

In this configuration, the light from the stage 2 surface (FIG. 1a) is appropriately focused and reflected by the light source reflection plate 18, and the original image 15 is illuminated from behind with a sufficient amount of light as shown in FIG. 1b. . And original picture 15
The light that has passed through is refracted and expanded by the lens means 14, and an enlarged image is formed on the image reflection plate 12. Note that points A and B on the original image 15 are located on the video reflection plate 12.
Images are formed in opposite directions as A' and B'.
The image reflecting plate 12 is tilted by a predetermined angle θ, and the lens means 14 and the like are further inclined by a predetermined angle θ, so that the image reflecting plate 12
The enlarged image connected to the screen is reflected by the image reflection plate 12, and is incident on the lens 3 of the head section 5 of the OHP above through the image output port 13. Here, by tilting the image reflection plate 12 by a predetermined angle θ, the lens means 14 and the original image holding means 16 are tilted toward the image reflection plate 12.
It can be arranged so as not to be located above the image reflection plate 12, and the enlarged image of the image reflection plate 12 can be incident on the head section 5 without any path being obstructed. The enlarged image incident on the head section 5 is further enlarged by the lens 3 of the head section 5, and the optical axis is converted by the reflector 4, so that the original image 15 can be sufficiently projected onto a screen or wall (not shown) located at a distant location. The image is enlarged and projected as a clear image with a sufficient amount of light.

FIG. 4 is a longitudinal sectional view of a main part of another embodiment of the enlarged projection device for an overhead projector according to the present invention. In FIG. 4, the same members as in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

The embodiment shown in FIG. 4 differs from FIG. 1 in that a light source 19 such as a lamp is provided as an irradiation means in place of the light source reflection plate 18.

In this way, the light source that illuminates the original picture 15 from the back,
By providing a light source separate from the light source that illuminates the two surfaces of the stage, when using the magnifying projection device 10 for an overhead projector of the present invention, the magnifying projection device 10' of the present invention can be used without turning on the light source of the OHP main body 1. By turning on the light source 19, the small original image 15 can be directly illuminated with a desired amount of light, and a clear enlarged image can be obtained. Furthermore, the structure is extremely simple compared to the light source reflection plate 18 shown in FIG.

Note that the original image holding means 16 for holding the original image 15 at a predetermined angle on the lens optical axis line V ₁₄ is not limited to the above-mentioned embodiment, and may be used as long as it can hold the original image 15 at a desired position and angle and can easily replace the original image 15. It may have any structure. Furthermore, in the embodiments shown in FIGS. 1 to 3, the inner wall of the housing 11 may have a chain shape. Furthermore, the light source reflection plate 18 is not limited to a plane mirror, but may be a concave mirror. Also, the fourth
In the embodiment shown in the figure, a lens may be interposed between the original image 15 and the light source 19 so that the original image 15 can be illuminated efficiently. Furthermore, a concave mirror may be provided on the back side of the light source 19.

(Effects of the invention) Since the present invention is configured as described above, it produces the following effects. An image reflection plate placed on the stage directly below the head section with an optical axis perpendicular to the stage surface is tilted at a predetermined angle θ with respect to the stage surface, so an enlarged image of the original image is connected to this image reflection plate. The lens means for displaying the original image and the original image holding means can be arranged so as not to be located above the image reflecting plate, and the enlarged image of the image reflecting plate can be incident on the head part, and can be further enlarged and projected by the head part. Therefore, it is possible to project a clear enlarged image of a small original image from the head using a general transparent OHP. Since the lens optical axis of the lens means is tilted at a predetermined angle with respect to the image reflection plate, and the original image holding means is tilted at a certain angle, the original image can be enlarged and projected onto the screen without distortion. Moreover, since the head of the OHP is used for enlarged projection,
The lens means of this device only needs to magnify the original image and focus the image on the image reflection plate, and the entire device can be manufactured at a relatively low cost, which is extremely useful in practice.

If the original image is irradiated by condensing and reflecting the light from the stage surface, the light from the stage surface can be effectively utilized and the original image can be irradiated with a desired amount of light.

Additionally, if you provide a light source separate from the light source that illuminates the stage surface and directly illuminate the original image, you can easily illuminate a small original image with the desired amount of light with a simple configuration without having to turn on the OHP light source. be able to.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an enlarged projection device for an overhead projector according to the present invention, FIG. 2 is an external perspective view of FIG. 1, and FIG.
FIG. 4 is a perspective view of the appearance of the magnifying projection device of the present invention placed on an OHP stage, and FIG. be. 1... OHP body, 2... Stage, 5... Head section, 10, 10'... Enlargement projection device, 12...
...Video reflecting plate, 14...Lens means, 15...Original image, 16...Original image holding means, 18...Light source reflecting plate, 19...Light source, V ₁₂ ...Vertical line of image reflecting plate, V ₁₄ ... Lens optical axis of lens means, V ₁₅ ...
...The vertical lines of the original picture.

Claims (1)

[Claims for Utility Model Registration] (1) On the stage of a transmission type overhead projector, directly below the head portion having an optical axis perpendicular to the stage surface, the head portion is tilted at a predetermined angle θ with respect to the stage surface. A planar image reflection plate is provided, and the lens optical axis line is further tilted by the predetermined angle θ in the direction of inclination of the perpendicular line with respect to the vertical line of the image reflection plate so as to connect the enlarged image to the image reflection plate. and disposing a lens means on the opposite side of the image reflecting plate on the optical axis of the lens, further connecting an enlarged image to the image reflecting plate in a direction of inclination of the optical axis of the lens with respect to the optical axis of the lens. An original image holding means is provided for holding the original image by tilting a vertical line of the original image by a suitable angle, and an irradiation means for irradiating the original image from the opposite side of the lens means is provided, and is connected to the image reflecting plate. 1. An enlarged projection apparatus for an overhead projector, characterized in that the enlarged image is enlarged and projected through the head section. (2) The overlay according to claim 1, wherein the irradiation means is configured to condense and reflect the light from the stage surface with one or more light source reflection plates to irradiate the original image from the back side. Magnifying projection device for head projector. (3) The overlay according to claim 1, wherein the irradiation means is a light source different from the light source that irradiates the stage surface, and is configured to directly irradiate the original picture from the back side with this light source. Magnifying projection device for head projector.