JPH06289485A - Overhead projection and film thereof - Google Patents

Abstract

PURPOSE:To provide a distinct easy-to-view video without gradation by placing a light reflecting sheet integrally stuck to a film on the smooth surface of a Fresnel lens whose condensing surface turns downward and whose smooth surface turns upward and performing projection. CONSTITUTION:Light from a light source lamp 2 is reflected on a reflection mirror 3, condensed by the condensing surface 5c of the Fresnel lens 5b, passes through the film 9 from the smooth surface 5d, and is reflected in parallel by the light reflecting sheet 12 integrally stuck to the film 9. The reflected light reflected by the sheet 12 passes through the film 9 and returns to the Fresnel lens 5b again, and further it is condensed and reflected by the reflection mirror 3 to enter a projection lens 4, then it is enlarged and projected on a screen 8. Aluminum foil being the light reflection sheet 12 is constituted to have the same size as the film 9, whereby the light made incident on the lens 5b is uniformly reflected by whole parts of the sheet 12 and projected to the screen 8 through the Fresnel leans again, so that the excess light is prevented from being reflected.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to overhead projectors and films thereof.

[0002]

2. Description of the Related Art Conventionally, in the case of a conference or a lecture, a transparent material (original) is projected on a screen using an overhead projector (hereinafter referred to as a projector) for explanation.

FIG. 3 shows Japanese Patent Application No. 4-
FIG. 4 is a side sectional view showing a closed state of an overhead projector described in No. 225780 (hereinafter referred to as a conventional example), and FIG. 4 is a view showing light reflection in the conventional example.

In FIG. 3, reference numeral 1 is a main body of the ejector (hereinafter referred to as a main body), which is a light source lamp 2 and a first optical path changing unit
And the projection lens 4 for projecting the light from the first reflecting mirror 3 onto the screen 8 and the transparent light collecting surface 5c facing downward and the smooth surface 5d facing upward. It is composed of a Fresnel lens 5b on which 9 is placed. Reference numeral 6 denotes a material cover, which is composed of a flat second reflecting mirror 7 and a lid 10, and is a cover which comes into contact with the Fresnel lens 5b about the connecting shaft 11 so as to be openable and closable.

The material cover 6 shown by the alternate long and short dash line in the figure is in an open state.

Further, both the smooth surface 5d (hereinafter referred to as a stage) of the Fresnel lens 5b on which the material of this conventional example is placed and the second reflecting mirror are formed in a square shape.

Next, the operation of this conventional example will be described with reference to FIGS.

In FIG. 3, the light emitted from the light source lamp 2 is reflected by the first reflecting mirror 3 and proceeds to the Fresnel lens 5b. Then, the parallel light condensed by the condensing surface 5c of the Fresnel lens 5b passes through the material 9 placed on the smooth surface 5d of the Fresnel lens 5b and is reflected in parallel by the flat second reflecting mirror 7. Then, it returns to the Fresnel lens 5b again, and is further condensed, reflected by the first reflecting mirror 3 and enters the projection lens 4, and is enlarged and projected on the screen 8.

In this case, since the stage 5d and the second reflecting mirror 7 are square as described above, there is no problem when placing and projecting a square material (film) 9 conforming to this size. When a vertically or horizontally long film is projected, the light is reflected as shown in FIG.

In FIG. 4, (a) is a side sectional view showing reflection of light when a vertically long material (film) 9 is placed, and (b) is a plan view. In the figure, 7a is a gap formed between the film 9 and the smooth surface 5d of the Fresnel lens 5b and the second reflecting mirror 7.

The light X ₁ incident on the gap 7a is reflected as extra light by the second reflecting mirror 7 without passing through the film 9, and is reflected as X _{2 from} the first reflecting mirror 3 to the projection lens 4. It is projected on the screen 8 as the street.

[0012]

As described above, in the conventional example, when a vertically long or horizontally long material (film) is projected, extra light is reflected vertically or horizontally,
The light on the screen has a strong and weak part, which causes shading in the image. As a result, there is a problem that the image becomes difficult to see.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to obtain a clear and easy-to-see image by uniformly sharpening the entire surface of the screen without causing a shade portion in the image on the screen. To aim.

[0014]

Therefore, in claim 1 of the present invention, an overhead projector main body provided with a light source lamp, a first reflecting mirror for changing the optical path, a projection lens, and a transparent material mounting plate. And a material cover that is openably and closably in contact with the transparent material mounting plate and does not have a light reflection plate, and the transparent material mounting plate has a light collecting surface facing downward and a smooth surface facing upward. With an overhead projector characterized by a Fresnel lens composed of
The object is to solve the above problems and achieve the above objects.

Further, according to a second aspect of the present invention, a film for an overhead projector is characterized in that a light reflecting sheet is attached or adhered to a transparent film to be used as an integral body, thereby solving the above problems and achieving the above object. It's something you want to achieve.

[0016]

In the overhead projector of the present invention, the light emitted from the light source lamp is reflected by the first reflecting mirror, passes through the Fresnel lens and becomes parallel light, and passes through the material placed on the Fresnel lens. The light is reflected by the light reflection sheet, passes through the Fresnel lens again, is re-focused, enters the projection lens, and is enlarged and projected on the screen.

Further, since the film and the light reflection sheet have the same size and are integrally formed, the light flux passing through the film and the light flux reflected by the light reflection sheet match each other, and a clear image is displayed on the screen. can get.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view of an overhead projector (hereinafter referred to as a projector) which is an embodiment of the present invention, and FIG. 2 is a diagram showing a state of reflected light reflected from the light reflecting sheet surface of this embodiment. Is. In the figure, the same reference numerals as those used in the conventional example indicate the same or corresponding components, and the duplicated description will be omitted.

The difference between this embodiment and the conventional example is that
In FIG. 3 showing the above conventional example, the material cover 6 has a second
However, this embodiment does not include the second reflector, and in this embodiment, a light such as an aluminum foil attached to or attached to the material (film) is integrated. It is to have a reflection sheet.

Since the other construction is the same as that of the above-mentioned conventional example, the duplicated description will be omitted.

Next, the operation of this embodiment will be described with reference to FIGS.

In FIG. 1, the light emitted from the light source lamp 2 is reflected by the first reflecting mirror 3 and proceeds to the Fresnel lens 5b. Then, the parallel light condensed by the condensing surface 5c of the Fresnel lens 5b passes through the film 9 from the smooth surface 5d of the Fresnel lens 5b and is reflected in parallel by the light reflection sheet 12 integrally attached to the film 9. . And light reflection sheet 1
The reflected light reflected in parallel by 2 passes through the film 9 and returns to the Fresnel lens 5b again, and is further condensed and reflected by the first reflecting mirror 3 to enter the projection lens 4, which is enlarged and projected on the screen 8. To be done.

FIG. 2 is a diagram showing a state of light reflected by the light reflecting sheet of this embodiment.

In FIG. 2, since the aluminum foil which is the light reflecting sheet 12 has the same size as the material (film) as described above, the light a incident on the Fresnel lens is a.
₁ is a light reflection sheet 1 through a film from a Fresnel lens
Since it is reflected uniformly in all the portions of 2 and again projected from the film through the Fresnel lens, the first reflecting mirror 3 and the projection lens 4 and onto the screen 8, no extra light is reflected. . As a result, the screen 8 will not be visually unsightly due to the light and shade of light.

[0026]

As described above, according to the present invention, the light reflecting sheet integrated with the film is placed on the smooth surface of the Fresnel lens with the light collecting surface facing downward and the smooth surface facing upward. By projecting, it is possible to obtain a clear and easy-to-see image by making the entire screen uniform and clear without causing shading in the image on the screen.

[Brief description of drawings]

FIG. 1 is a side sectional view of an overhead projector that is an embodiment of the present invention.

FIG. 2 is a diagram showing a state of reflected light reflected from a light reflecting sheet surface of this embodiment.

FIG. 3 is a side sectional view of a conventional overhead projector.

FIG. 4 is a diagram showing a state of reflected light reflected from the surface of a second reflecting mirror of a conventional example.

[Explanation of symbols]

 1 Main Body 2 Light Source Lamp 3 First Reflector 4 Projection Lens 5b Fresnel Lens 5c Condensing Surface 5d Smooth Surface 6 Material Cover 8 Screen 9 Material (Film) 10 Lid 11 Rotation Axis 12 Light Reflecting Sheet

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[Procedure amendment]

[Submission date] October 7, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

In FIG. 3, the light emitted from the light source lamp 5 is reflected by the first reflecting mirror 3 and proceeds to the Fresnel lens 5b. Then, the light is collected by the light collecting surface 5c of the Fresnel lens 5b.
Light passes through the article 9 placed in the smooth surface 5d of the Fresnel lens 5b, back again Fresnel lens 5b shines separated by the second reflecting mirror 7 plane, is further condensing First
The light is reflected by the reflecting mirror 3 and enters the projection lens 4, and is enlarged and projected on the screen 8.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

[Action] with an overhead projector of the present invention, light emitted from the light source lamp is reflected by the first reflecting mirror, passes through the placed article on the Fresnel lens passes through the Fresnel lens, the light reflecting sheet It is reflected, re-focused again through the Fresnel lens, enters the projection lens, and is magnified and projected on the screen.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

In FIG. 1, the light emitted from the light source lamp 2 is reflected by the first reflecting mirror 3 and proceeds to the Fresnel lens 5b. Then, the light is collected by the light collecting surface 5c of the Fresnel lens 5b.
Light passes through the film 9 from the smooth surface 5d of the Fresnel lens 5b, as Isa anti in the light reflecting sheet 12 which is attached integrally to the film 9. Then, the light reflected The reflected light anti Isa sheet 12 again Fresnel lens through the film 9 5
Returning to b, the light is further condensed, reflected by the first reflecting mirror 3, enters the projection lens 4, and enlarged and projected on the screen 8.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (2)

[Claims] 1. An overhead projector main body provided with a light source lamp, a first reflecting mirror for changing an optical path, a projection lens, and a transparent material mounting plate, and the transparent material mounting plate is opened and closed freely. A document cover without a light reflector,
An overhead projector comprising the transparent material mounting plate as a Fresnel lens having a light collecting surface facing downward and a smooth surface facing upward. 2. A film for an overhead projector, wherein a light reflecting sheet is attached or adhered to a transparent film to be used as an integral body.