JPH0545006B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention first projects recorded image information or transmitted image information onto a CRT screen, and then displays this projected image (hereinafter referred to as a CRT image). The present invention relates to a projector for enlarging and projecting a CRT image onto a screen, and particularly to an optical device for a projector for enlarging a CRT image.

[Conventional technology]

In recent years, a projector as shown in Figure 4 has been developed in order to reproduce information recorded on an image recording device, etc. onto a CRT screen, and enlarge and project it onto the screen. , an image forming apparatus (not shown) having CRTa,
Some devices include an optical device c that enlarges a CRT image and projects it onto a screen b.

By the way, as shown in Figure 5, this optical device for projectors usually uses a combination of multiple lenses.・
In order to facilitate replacement work, the lens group e is divided into a lens group e attached to a lens holder d, and a CRT lens g adjacent to the front side of the CRTa and attached to a holder f. In the space formed by the CRT holder h attached to the fixed part and the front side of the CRTa, a lens identical to that of the CRT lens g is placed in order to dissipate the heat generated from the CRTa and prevent the attenuation of light rays from the CRT image. There is a structure filled with a liquid i having a refractive index. Then, an optical device with such a configuration is
When installing on the front side of the CRTa, first align and center the holder f and lens holder d, screw the holder f side onto the lens holder d side with the screw x, and then attach the lens holder d to the CRT. holder h
It is designed to be positioned and centered, and then screwed in with screw y.

In addition, between the CRT lens g and the CRT holder h, and between the CRT holder h and the front side of the CRTa, rubber is installed as shown in Figure 6 to prevent liquid from leaking between these spaces. A sealing means j formed of, etc. is provided.

[Problem to be solved]

By the way, in the optical device for a projector having such a configuration, as shown in FIG. Because it has a special cylindrical shape, its structure and installation are difficult.
There is a problem with sealing against liquid.

In addition, in the optical device for a projector having such a configuration, the light rays from the CRTa may be reflected by the sealing means j and then enter the screen (not shown) to adversely affect the projected image. be.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional art, the present invention provides an optical device for a projector that has good sealing properties against liquid, is provided with a sealing means of a simple shape, and is capable of projecting a good image on a screen. Our goal is to provide the following.

[Means for solving problems]

That is, the present invention includes a CRT holder fixed to a fixed portion of a CRT, a lens group consisting of a plurality of lenses, a lens group fixed and held, and a CRT holder.
A lens holder screwed onto the holder and the CRT
A CRT lens located between the front lens group,
In order to fix and hold this CRT lens,
The space formed by the holder provided between the CRT holder and the lens holder, the CRT lens, the CRT holder, and the front surface of the CRT is filled with
A liquid that has the same refractive index as the CRT lens, and this liquid is placed between the CRT lens and the CRT holder and
In an optical device for a projector that enlarges and projects an image on a CRT screen onto the screen, the sealing means is arranged to prevent leakage from between the front surface of the CRT and the CRT holder.
A cylindrical sealing body or a sealing adhesive body that prevents the liquid from leaking between the lens and the CRT holder, and a rectangular sealing body that prevents the liquid from leaking between the CRT front side and the CRT holder. or a viscous material for sealing, and the CRT
A light shielding means for absorbing incident light is provided in a certain area on the front end side of the lens, and in order to reflect the light incident from the CRT onto the inner peripheral surface of the CRT holder opening toward the light shielding means, the CRT The inner peripheral surface of the holder is formed into a tapered shape.

[Effect]

In the optical device for a projector of the present invention, the sealing means is composed of a cylindrical seal body and a rectangular seal body each having a simple shape.
Since these can be arranged separately in different parts, it is easy to manufacture these cylindrical seal bodies and rectangular seal bodies, and the installation work can be carried out easily and reliably. This improves sealing performance and also allows CRT
The inner circumferential surface of the holder is formed into a tapered shape (hereinafter referred to as a tapered surface) with a constant inclination angle toward the tip, and even if a ray of light from a CRT image is incident on this tapered surface, the ray will be Since the light is absorbed by the light shielding means on the front end of the CRT lens and does not enter the lens group, the image projected onto the screen is not disturbed by the light, improving image quality. This is what happens.

〔Example〕

Hereinafter, a practical example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an optical device for a projector according to the present invention. This optical device for a projector includes a sealing means 1 divided into two parts, and a CRT lens 3 having a light shielding means 2 on the peripheral edge of the tip side. and,
The CRT holder 4 has a tapered inner peripheral surface. In addition, numeral 5 is a lens group, 6 is a lens holder that fixes and holds the lens group 5, and 7 is a lens group.
The holding body L for fixing and holding the CRT lens 3 is a liquid, and these constitute the optical device for a projector of the present invention, but the same ones as those used in the past are used. Further, reference numeral 8 is a CRT.

The sealing means 1 seals between the CRT lens 3 and the CRT holder 4, as shown in FIG.
It is composed of a cylindrical seal body 1a having a cylindrical shape and made of rubber or the like, and a rectangular seal body 1b having a square column shape and made of rubber or the like to seal between the front side of the CRT 8 and the CRT holder 4. has been done.
The cylindrical seal body 1a and the rectangular seal body 1b are designed to prevent the light rays from the CRT8 screen from being scattered by the cylindrical seal body 1a and the rectangular seal body 1b and disturbing the image on the screen (not shown). It is colored black etc.

As shown in FIG. 3, the CRT lens 3 is composed of a concave lens having a concave curved surface 3a on the distal end side, and a peripheral edge 3b excluding the curved surface 3a of the distal end surface.
In this embodiment, a light-shielding paint such as black is applied to the outer peripheral surface 3c side in order to absorb unnecessary light rays by the light-shielding means 2 and prevent these light rays from entering the lens group 6 side. .

In the CRT holder 4, the inner circumferential surface 4a of the opening that comes into contact with the liquid L forms a tapered surface that is inclined at a constant angle toward the tip side, and the scattered light reflected on this tapered surface is used as a light shielding means 2. The light is absorbed by the light-shielding paint used and enters the lens group 6 so that it does not disturb the image on the screen (not shown). In addition, the tapered surface of the opening allows the light from the CRT to
In order to make the light incident on the lens 3 effectively, it is desirable to taper so that the aperture on the CRT lens side becomes wider.

Therefore, according to the optical device for a projector according to this embodiment, the sealing means 1 is formed separately from the cylindrical seal body 1a having a simple shape and the rectangular seal body 1b having a similarly simple shape. Ori,
These can be installed separately.

In addition, according to the optical device for a projector according to this embodiment, scattered light on the inner circumferential surface side of the CRT holder 4, which may deteriorate the image quality of the image projected on the screen, is effectively prevented by the light-shielding paint. absorbed,
It does not enter the lens group 6 side.

〔effect〕

As described above, according to the optical device for a projector according to the present invention, the sealing means is divided into two parts, both of which have a simple shape. It is easy to use and can reduce costs, and since the sealing means can be installed separately, the work is easy and reliable, and the sealing performance against the filled liquid is improved, so it has extremely high practical value. .

Further, according to the optical device for a projector according to the present invention, the peripheral edge of the CRT lens on the distal end side has a
A light shielding means is provided so that the light rays scattered on the inner peripheral surface of the CRT holder are incident and absorbed, thereby preventing the image projected on the screen from being disturbed by the scattered light. The image quality can be dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a state in which the optical device for a projector according to the present invention is attached to a CRT, and FIGS. 3 is a schematic perspective view showing a CRT lens of the optical device for a projector according to the present invention, FIGS. 4a and 4b are schematic configuration diagrams showing the projector, and FIG. 5 is a conventional one. FIG. 6 is a schematic cross-sectional view showing a state in which an optical device for a projector of this type is attached to a CRT, and FIG. 6 is a perspective view showing a conventional sealing means. 8...CRT, 4...CRT holder, 5...Lens group, 6...Lens holder, 3...CRT lens,
7...Holding body, L...Liquid, 1...Sealing means, 1
a... Cylindrical seal body, 1b... Square seal body, 3
a...Curved surface, 2...Shading means, 4a...(CRT
holder) inner peripheral surface.

Claims (1)

[Claims] 1. A CRT holder fixed to a fixed part of a CRT;
A lens group consisting of a plurality of lenses, a lens holder that fixes and holds this lens group and is screwed onto the CRT holder, a CRT lens located between the front side of the CRT and the lens group, and this CRT lens. In order to fix and hold the lens, the space formed by the CRT lens, the CRT holder, and the front surface of the CRT is filled with a holder provided between the CRT holder and the lens holder, and a lens having the same refraction as that of the CRT lens is filled. The image on the CRT screen is magnified onto the screen by a liquid having a high temperature and a sealing means arranged to prevent this liquid from leaking between the CRT lens and the CRT holder and between the front surface of the CRT and the CRT holder. - In an optical device for a projector that projects images, the sealing means includes a cylindrical sealing body or a sealing viscous body that prevents the liquid from leaking between the CRT lens and the CRT holder, and a sealing member that connects the CRT front side and the CRT holder. a rectangular sealing body or a sealing viscous body to prevent the liquid from leaking between the CRT lens, and a light shielding means for absorbing incident light in a certain area on the front end surface side of the CRT lens; 1. An optical device for a projector, characterized in that the inner circumferential surface of the CRT holder is formed into a tapered shape in order to reflect light incident on the inner circumferential surface of the CRT holder opening toward the light shielding means.