JPH01276888A - Projection type television receiver - Google Patents

Abstract

PURPOSE:To suppress the unnecessary reflection of the light between a glass plate and a lens and to obtain a high contrast by enclosing a solution having approximately the same refraction factor as that of the glass plate between the glass plate of a CRT unit and the lens. CONSTITUTION:Solutions 6 and 8 having approximately the same refraction factor as that of a glass 7 are enclosed into the gaps between the CRT tube surface of a CRT unit 5 and the glass 7, and between the glass 7 and a lens 9. Since the CRT 5 is cooled by the solution 6, large injection power can be applied, and since the glass plate 7 is inserted and set between the solution 6 and the lens 9, the solution 6 and the lens 9 are shielded, the heat of the solution 6 does not conducted to the lens 9, and a lens material can be widely selected in the viewpoint of heat resistance. Thus, the unnecessary light reflection does not occur between the CRT and the lens 9, and the high contrast can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection television receiver (hereinafter referred to as a video projector), and particularly relates to an improvement of a CRT unit thereof.

[Conventional technology]

FIG. 2 is a sectional view showing the structure of a CRT unit of a conventional video projector.
is a glass plate, and 4 is a lens.

Moreover, 2 is a liquid sealed between the CRTI and the glass plate 3 and having almost the same refractive index as the glass plate 3 .

Next, the effects of the conventional device will be explained.

In the apparatus shown in FIG. 2, the liquid 2 is exposed to C due to electron beam collision.
Heat generated on the RTIO tube surface is cooled down by natural convection. As described above, the liquid 2 used here has a refractive index similar to that of the glass plate 3, so that reflection of light emitted from the CRTI tube surface can be suppressed. Also, this liquid 2
Since the glass plate 3 is inserted and installed between the liquid 2 and the lens 4, the liquid 2 and the lens 4 are cut off, and the heat of the liquid 2 is not transmitted to the lens 4. From the viewpoint of heat resistance, a wide range of lens materials can be used. It is possible to choose.

[Problem to be solved by the invention]

The CRT unit used in conventional video projectors is constructed as described above, and since there is air between the glass plate and the lens, reflection occurs due to the difference in refractive index between the air and the glass, reducing contrast. There was a problem with that.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a projection type television receiver having a CRT unit that does not cause reflection of light between a glass plate and a lens.

[Means to solve the problem]

The projection television receiver according to the present invention has a CR
Between the CRT tube surface of the T unit and the glass.

A liquid having a refractive index approximately equal to that of the glass is filled in both spaces between the glass and the lens.

[Effect]

In this invention, since the space between the glass of the CRT unit and the lens is also filled with a liquid having a refractive index almost equal to that of the glass, unnecessary reflection of light is suppressed.
High contrast can be obtained.

〔Example〕

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

FIG. 1 is a diagram showing the structure of a CRT unit used in a projection television receiver according to an embodiment of the present invention. In the figure, 5 is a CRT, 7 is a glass plate, 9 is a lens, 6, 8 Both are liquids having almost the same refractive index as the glass plate 7.

Next, the operation will be explained.

As in the conventional device, the CRT 5 is cooled by the liquid 6, so a large injection power can be applied. Also,
Since the glass plate 7 is inserted and installed between the liquid 6 and the lens 9, the liquid 6 and the lens 9 are cut off, and the liquid 6
The heat is not transferred to the lens 9, and from the viewpoint of heat resistance, it is possible to select a wide range of materials for the lens.

Furthermore, in this embodiment, a liquid 8 is also sealed between the glass plate 7 and the lens 9, and since both liquids 6 and 8 have the same refractive index as the glass plate 7, unnecessary No light reflection occurs, and high contrast can be achieved.

(Effects of the Invention) As described above, according to the present invention, a projection television receiver has a structure in which a liquid having a refractive index substantially equal to that of the glass plate is sealed between the glass plate of the CRT unit and the lens. Therefore, unnecessary reflection of light between the glass plate and the lens is suppressed, and a projection television receiver with high contrast can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a CRT unit used in a projection television receiver according to an embodiment of the present invention, and FIG. 2 is a diagram showing the structure of a CRT unit used in a conventional projection television receiver. . 5 is a CRT, 6.8 is a liquid, 7 is a glass plate, and 9 is a lens.

Claims (1)

[Claims] (1) In a projection television receiver, a cathode ray tube (
A glass plate is inserted between the glass plate (hereinafter referred to as a CRT) and the lens, and the glass plate is provided in both the space between the glass plate and the CRT and the space between the glass plate and the lens. A projection television receiver characterized by being filled with a liquid having approximately the same refractive index.