JPH099186A - Projection type receiver - Google Patents

Abstract

PURPOSE: To prevent the reduction in the contrast performance by combining a space between a face of a cathode ray tube and a lens arranged in front of the cathode ray tube with a radiator in which liquid is filled, and arranging a recessed part to a face side in contact with the liquid of the lens. CONSTITUTION: A cathode ray tube 1 and a lens 2 are coupled with a radiator 4, in which a coolant 3 is filled. Five recessed parts 6 are provided to a lower face of a flange 5 of the lens 2, that is, a face in contact with the coolant 3. Air bubbles 7 generated in the coolant 3 enter an elliptic recessed part 6 at a highest position, resulting that the residence of the air bubbles 7 in the vicinity of the effective part of the lens 2 is avoided to prevent deterioration in the contrast performance. Moreover, the recessed parts 6 and the surrounding are colored in black to absorb even a slight undesired reflecting light caused by the air bubbles. Should the air bubbles be produced in the coolant, the air bubbles are collated at a position apart from the optical path and resident thereat to prevent deterioration in the contrast performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type receiver for magnifying and projecting an image projected on a receiver by using a projection lens.

[0002]

2. Description of the Related Art In recent years, in projection type image receivers, for the purpose of cooling and improving the contrast on the projection screen,
It has become mainstream to use a technique of filling a transparent liquid between a cathode ray tube and a projection lens. Since projection light is transmitted through the transparent liquid enclosed between the cathode ray tube, the liquid container (hereinafter referred to as the radiator), and the coupling lens (hereinafter referred to as the lens), if bubbles exist in the transparent liquid, the liquid and the bubbles will be separated from each other. It has been found that unnecessary reflection of light occurs at the boundary surface of, which deteriorates the contrast performance.

Therefore, it is necessary to prevent air bubbles from being mixed in at the time of filling the liquid, and to collect the air bubbles in a portion far away from the optical path even if they are generated in the liquid.

A conventional projection type receiver will be described below with reference to the drawings. FIG. 4 is a schematic view showing an example of a configuration of a conventional projection type receiver viewed from the side. The image projected on the cathode ray tube 1 is enlarged by the projection lens 10 and projected on the screen 12 via the mirror 11. Cathode ray tube 1 and projection lens 1
The installation angle θ of the optical unit composed of 0 is generally set to an angle of 60 ° to 80 ° in order to effectively arrange and secure the projection distance required by the projection lens 10 in the housing 13 of the receiver. Many.

FIG. 5 is an enlarged sectional view of the optical section of FIG.
The cathode ray tube 1 and the lens 20 are connected by the radiator 4,
The refrigerant liquid 3 is filled therein. Even if a bubble is mixed or generated in the refrigerant liquid 3, the optical part is installed so as to be inclined, so that the bubble 7 gathers at the corner portion of the radiator, which becomes higher in position, and stays at that position.
Since it is far away from the optical path of the projection light, the influence of the unnecessary reflected light 15 on the deterioration of the contrast performance is small.

Further, a method of providing a bubble pool in the radiator 4 in order to completely expel the bubble out of the optical path (actually, the flat plate 6-
31280 gazette) etc. are also proposed.

On the other hand, recently, with the adoption of a short-focus lens capable of shortening the projection distance, the optical part is vertically (θ = 90 °) in order to reduce the height of the housing due to the demand for a tabletop type image receiver. Install (lens faces right above)
Things have also been done. FIG. 6 is a block diagram showing an example thereof.

FIG. 7 is an enlarged sectional view of the optical section of FIG.
The bubbles 7 generated in the refrigerant liquid 3 are retained vertically on the lower surface 9 of the flange portion around the lens because the optical portion is vertically installed.

[0009]

Therefore, in such a conventional structure, when the optical portion is installed vertically, the bubbles generated in the refrigerant liquid stay near the optical path under the lens flange portion, and The unnecessary reflected light generated at the interface between the bubble and the bubble increases, and as a result, the contrast performance deteriorates.

Further, even if a bubble reservoir is provided in the radiator, it must be provided at a position higher than the lens flange portion, which is structurally difficult, and even if it is possible, the structure will be complicated and the cost will be high.

Further, in order to suppress the invasion of air bubbles at the time of assembling, a defoaming step, a careful assembling work and the like are required, which leads to an increase in the number of steps.

The present invention solves the above problem. Even if bubbles are generated in the refrigerant liquid when the optical unit is installed vertically, the bubbles are collected at a position distant from the optical path and stayed there, thereby improving the contrast. The purpose is to prevent the deterioration of performance at low cost.

[0013]

In order to achieve the above object, the present invention comprises a concave portion formed on the entire inner circumference or a part of the inner side of the coupling lens flange portion.

Further, the concave portion and its vicinity are painted black or the like. Further, the diameter of the coupling lens is larger than its effective diameter, and the portion outside the effective diameter is painted black.

Further, the inner side surface of the flange portion of the coupling lens (the surface side in contact with the refrigerant liquid) is provided with a tapered surface whose thickness decreases from the inner circumference to the outer circumference.

[0016]

According to the present invention, with the above configuration, even if bubbles are generated in the refrigerant liquid when the optical unit is installed vertically, the bubbles are gathered at a position apart from the optical path and retained, so that the contrast performance is deteriorated. It is possible to realize the prevention at low cost.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. The same components as those in the conventional example are designated by the same reference numerals.

(Embodiment 1) FIG. 1 (A) is a sectional view showing the main part of a projection type image receiver according to the first embodiment of the present invention. FIG.
1B shows a plan view of FIG.

In FIG. 1A, a cathode ray tube 1 and a lens 2 are connected by a radiator 4, and a refrigerant liquid 3 is filled therein. A plurality of recesses 6 are provided on the lower surface of the flange portion 5 of the lens 2, that is, on the surface side that contacts the refrigerant liquid 3. In the embodiment of the present invention, FIG.
It shows in (B).

The bubbles 7 generated in the refrigerant liquid 3 enter the oval recess 6 which is highest in position, and as a result,
The bubbles 7 do not stay near the effective portion of the lens 2 and prevent deterioration of the contrast performance.

Furthermore, by forming the concave portion 6 and its surroundings black (for example, by means of painting or the like), it becomes possible to absorb even a slight amount of unnecessary reflected light caused by bubbles.

The concave portion 6 may be provided not only on a part of the flange portion 5 but also on the entire circumference.

(Embodiment 2) FIG. 2 is a sectional view of the essential parts of a projection type image receiver according to a second embodiment of the present invention. In FIG. 2, the lens 2A has an outer diameter larger than its effective diameter L, and the portion outside the effective diameter is painted black.

Since the generated bubbles 7 move to the black portion 8 outside the effective diameter, generation of unnecessary reflected light can be prevented.

(Embodiment 3) FIG. 3 is a sectional view showing the main part of a projection type image receiver in the third embodiment of the present invention. In FIG. 3, the inner surface 9 of the flange portion of the lens 2B, that is, the surface side in contact with the refrigerant liquid 3 is provided with a tapered surface whose thickness decreases from the inner circumference to the outer circumference.

The generated bubbles 7 move along the tapered surface and are expelled to the outer peripheral portion of the flange portion, which becomes higher in position. As a result, the bubble 7 is far away from the optical path, and the generation of unnecessary reflected light can be prevented.

As described above, in any of the above-mentioned embodiments, since the countermeasure against bubbles can be dealt with only by the lens shape, the structure is extremely simple and can be implemented at low cost.

[0028]

As is apparent from the above-described embodiments, according to the projection type image receiver of the present invention, even if bubbles are generated in the refrigerant liquid when the optical section is installed vertically, the bubbles will not be generated. It is possible to prevent the contrast performance from deteriorating by collecting and staying at a position distant from the optical path. as a result,
It is possible to provide an inexpensive projection type image receiver with high image quality.

[Brief description of drawings]

FIG. 1A is a sectional view of a main part of a projection type image receiver according to a first embodiment of the invention. FIG. 1B is a plan view of FIG.

FIG. 2 is a sectional view of an essential part of a projection type image receiver according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an essential part of a projection type image receiver according to a third embodiment of the present invention.

FIG. 4 is a side view of a conventional projection type receiver.

5 is a cross-sectional view of the main parts of the optical unit in FIG.

FIG. 6 is a side view of a conventional projection type receiver.

7 is a cross-sectional view of the main parts of the optical unit in FIG.

[Explanation of symbols]

 1 Cathode Ray Tube 2, 2A, 2B Lens 3 Refrigerant Liquid 4 Radiator 5 Flange 6 Recess 7 Bubble 8 Black Part 9 Inner Side

Claims (4)

[Claims] 1. A cathode surface of a cathode ray tube and a lens arranged in front of the cathode surface are connected by a radiator filled with a liquid, and a concave portion is provided on a surface side of the lens which is in contact with the liquid. Characteristic projection type receiver. 2. The projection type image receiver according to claim 1, wherein the concave portion is formed in black. 3. A cathode surface of a cathode ray tube and a lens arranged in front of the cathode surface are connected by a radiator filled with a liquid, and a portion outside the effective diameter of the lens is black. Projection type receiver. 4. The space between the face surface of the cathode ray tube and the lens arranged in front of the cathode ray tube is connected by a radiator filled with a liquid, and the surface of the lens in contact with the liquid extends from the inner circumference to the outer circumference of a wood end. A projection type image receiver having a tapered surface with a reduced thickness.