JPS62254132A - Projecting device - Google Patents

Abstract

PURPOSE:To save space and to obtain a bright large screen by arranging a convergent Fresnel lens in front of a panel sheet, providing a light source and an image forming lens in front of this convergent Fresnel lens, and providing a reflecting mirror behind the panel sheet. CONSTITUTION:The convergent Fresnel lens 4 converges light from the light source 5 on in front of a liquid crystal panel 2 to irradiate the entire surface of the liquid crystal panel 2 with the illumination light, and also converges light reflected by a reflecting mirror 3 to project the light to the overall diameter of the image forming lens 7, thereby obtaining the bright large screen. Further, the convergent Fresnel lens 4 is arranged in front of the liquid crystal panel 2 and the light source 5 and image forming lens 7 are arranged in front of the lens to shorten the length of the optical path, thereby saving the space.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a projection device.

2. Description of the Related Art Conventionally, as shown in FIG. 3, a transmissive Fresnel lens 32 on which a transparent sheet 31 with an image is placed, and an illumination lamp 33 located below the lens are mounted on the top of a housing 34. , an imaging lens 35 and a reflection mirror 36 are provided, the light from the illumination lamp 33 is focused by the transmission type Fresnel lens 32 to illuminate the transparent sheet 31, and the light transmitted through the transparent sheet 31 is transmitted through the imaging lens 35. Reflection mirror 3
6 there is an over-rad projector that is reflected towards the screen.

In addition, as a device described in Japanese Utility Model Application Publication No. 60-115232, as shown in FIG.
An illumination lamp 40, an imaging lens 41, and a reflecting mirror 42 are placed in the second part of the housing 39, which illuminates the transparent sheet on the Fresnel lens 37 from above, and the reflected light is sent to the imaging lens. 41 and a reflective mirror 42.
There is an over rad projector that reflects towards the screen.

Furthermore, as a device described in Japanese Utility Model Application Publication No. 60-96681, as shown in FIG.
The image of the liquid crystal panel 43 illuminated by the illumination lamp 44 is transmitted through the imaging lens 45 and reflected by the reflection mirror 46.
There is an over rad projector which reflects the light towards the screen 47.

Problems to be Solved by the Invention In the case shown in FIG. 3, the illumination lamp 33 is placed below the transmission type Fresnel lens 32, so the casing 34 becomes large and the distance between the transparent sheet 31 and the transmission type Fresnel lens 32 increases. Since the light transmitted from the back side is imaged, the optical path length becomes long and a large space is required. Moreover, the transparent sheet 31 on which the image is drawn must be prepared in advance, and flexible usage such as changing the projected image on the spot is not possible.

4, the illumination lamp 40 is connected to the imaging lens 4.
1 and the reflective mirror 42 above the housing 39, it is possible to make the housing 39 thinner, but the disadvantage of operability due to the use of a transparent sheet remains.

In the case shown in FIG. 5, the light from the illumination lamp 44 is not focused and is irradiated onto the liquid crystal panel 43, so the screen 47
The projected image above also becomes darker.

The present invention has been made in view of these points, and an object of the present invention is to provide a projection device that can save space and provide a bright, large screen.

Means for Solving the Problem A condensing Fresnel lens is placed just before the panel sheet whose light transmittance and scattering state change depending on external signals, and a light source and an imaging lens are provided in front of the condensing Fresnel lens. A reflective mirror is provided behind the panel sheet.

Accordingly, the panel sheet is illuminated by a light source, the illumination light is reflected by a reflective mirror at the rear of the panel sheet, and an image of the panel sheet is transmitted through an imaging lens and projected.

A condensing Fresnel lens condenses the light rays from the light source just in front of the panel sheet, illuminates the entire surface of the panel sheet, and condenses the light rays reflected by the reflection mirror so that they illuminate the entire aperture of the imaging lens. This makes it possible to obtain a bright, large screen. Furthermore, by arranging a condensing Fresnel lens just before the panel sheet and arranging the light source and imaging lens in front of it, the optical path length is shortened and space is saved.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. A liquid crystal panel 2, which is a panel sheet, a reflective mirror 3 located on the back of the liquid crystal panel 2, and a condensing Fresnel lens 4 close to the front of the liquid crystal panel 2 are arranged in a leaning state inside the casing l. In front of Fresnel lens 4,
A light source 5 using a halogen lamp, a condenser lens 6, and an imaging lens 7 are arranged. Furthermore, legs 8 are attached to both sides of the casing 1 so as to be rotatable and fixable at any position for changing the elevation angle of the casing 1.

A personal computer 10 to which the liquid crystal panel 2 is connected via an interface circuit 10a via a cable 9 is provided with a storage device 11, a video camera 13 for photographing a subject such as a document 12, and a still image storage device 14.
A word processor 15, an image scanner 16, and a mouse 17 are connected. These personal computers 10 and video cameras 1 serve as external image input devices.
3. Still image storage device 14, word processor 15, image scanner 16, etc. may be connected to liquid crystal panel 2 independently. Also, the panel sheet is replaced with LCD panel 2,
T'N liquid crystal panel, smectic liquid crystal panel, ECD
A phase changeable panel sheet such as a panel or T e Ox may also be used.

In such a configuration, images are selectively input to the liquid crystal panel 2 from any of the external image input devices, and images can be freely changed and new images created on the spot. for example,
A photographic screen of a subject such as the manuscript 12 photographed by a video camera 13, a screen on the manuscript 12 optically read by an image scanner 16, a text or image created on a personal computer 10 using a mouse 17, etc., a word processor 15 The sentences etc. created by the above are input to the liquid crystal panel 2. In addition, an image signal from any external image input device is inputted to the still image storage device 14, and the image is inputted as it is to the liquid crystal panel 2, or a part of the image is added to or deleted from the image by the personal computer 10, etc. You can freely input data to the liquid crystal panel 2 while processing the data.

Further, when a smectic liquid crystal panel is used in place of the liquid crystal panel 2, an image once input can be stored semi-permanently unless it is rewritten, and there is an advantage that loss of light amount is reduced.

The image thus formed on the liquid crystal panel 2 is projected onto the screen 18. That is, the light rays from the light source 5 are diffused by the condenser lens 6 into an area corresponding to the size of the liquid crystal panel 2, and further condensed by the condensing Fresnel lens 4 to avoid waste, and irradiated onto the liquid crystal panel 2 all at once. be done. This illumination light is reflected by a reflection mirror 3, and further condensed by a condensing Fresnel lens 4 so as to illuminate the entire aperture of an imaging lens 7, and projected onto a screen 18.

In this way, an image is projected. The condensing Fresnel lens 4 condenses the light rays from the light source 5 just in front of the liquid crystal panel 2 and illuminates the entire surface of the liquid crystal panel 2, and the light beams reflected by the reflection mirror 3 It becomes possible to condense the light so that it illuminates the entire aperture of the imaging lens 7, and a bright large screen can be obtained.

Further, by arranging the condensing Fresnel lens 4 immediately before the liquid crystal panel 2 and arranging the light source 5 and the imaging lens 7 in front of it, the optical path length can be shortened and space can be saved.

Effects of the Invention Since the present invention is configured as described above, the panel sheet is illuminated by a light source, the illumination light is reflected by the reflective mirror at the rear of the panel sheet, and the image of the panel sheet is transmitted through the imaging lens and projected. However, a condensing Fresnel lens condenses the light rays from the light source just in front of the panel sheet, illuminates the entire surface of the panel sheet, and also irradiates the light rays reflected by the reflection mirror onto the entire aperture of the imaging lens. It is possible to condense light, and therefore a bright large screen can be obtained.Also, by placing a condensing Fresnel lens just in front of the panel sheet and placing the light source and imaging lens in front of it, the optical path length can be reduced. This has the effect of shortening the time and saving space.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 show an embodiment of this invention.
FIG. 1 is a longitudinal side view, FIG. 2 is a side view showing a connection state of an external image input device in a reduced scale, and FIGS. 3 to 5 are side views showing a conventional example. 2...Liquid crystal panel (panel sheet), 3...Reflecting mirror, 4...Condensing Fresnel lens, 5...Light source, 7
...imaging lens

Claims (1)

[Claims] A condensing Fresnel lens is placed just before the panel sheet whose light transmittance and scattering state change depending on an external signal, a light source and an imaging lens are provided in front of the condensing Fresnel lens, and a reflection mirror is installed behind the panel sheet. A projection device characterized by being provided with.