JP2573582Y2 - Cathode ray tube - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube having a structure in which the getter agent adheres to a fluorescent film on a face plate when the getter agent is scattered from the cathode ray tube and does not adversely affect an image .

[0002]

2. Description of the Related Art In the manufacture of a cathode ray tube, a getter effect which is considered to effectively adsorb residual gas is used in order to increase the degree of vacuum in the cathode ray tube. To achieve this purpose, a getter agent having a getter effect must adhere to the vacuum-sealed cathode ray tube.
The getter agent loading section loaded with the getter agent generally uses a getter ring (ring), and the getter ring loaded with the getter agent is called a getter. The getter is usually installed at an arbitrary position in the cathode ray tube by a support member extended from the electron gun assembly.

In a small cathode ray tube used for a viewfinder of an image pickup apparatus, the neck diameter is extremely small and extremely short. A space for deflecting the electron beam is required within this short neck length, and it is difficult to install a getter having a large area parallel to the tube axis direction to secure this deflection space. Therefore, the getter is installed perpendicular to the tube axis direction to save space in the neck. In addition, the neck diameter of the small cathode ray tube is extremely small, and a support member that can strongly hold the getter is inserted into the neck with a support spring independent of the electron gun structure, and the getter is fixed to the support arm attached to this support spring A way to be taken. The support spring (getter support structure) provided with the support arm is called a getter holder. The getter holder is arranged by inserting the funnel from the opposite side of the face plate to the face plate. At this time, the getter is inserted from the getter holder supporting arm portion where the getter is supported. Therefore, the getter is located between the face plate and the getter holder as shown in FIG.

In the case where the getter agent is scattered from a getter installed perpendicular to the tube axis of the cathode ray tube, if the scattering direction is set to the electron gun side, the getter agent having electrical conductivity is applied to the side of the electron gun and its surroundings. And adheres to the inner wall surface of the neck, causing a discharge phenomenon or the like, thereby impairing the function as a cathode ray tube. For this reason, the scattering direction of the getter agent is set to the face plate side from the getter installed perpendicular to the tube axis. In this case, the scattered getter agent adheres to the inner wall surface of the neck and the fluorescent film on the face plate. In recent years, as shown in Figure 3,
A cylindrical shield is mounted on the inner diameter of the getter vertically to the getter. Further, the other end of the cylindrical obstacle, which is not attached to the getter, is folded back to the outside of the cylinder to direct the scattering of the getter agent toward the inner wall surface of the neck. Here, this cylindrical shield is referred to as a reflector. However , in a small cathode ray tube, getter and
Even if this reflector is attached because the base plate is close , the getter agent does not completely adhere to the neck wall surface but reflects and adheres to the fluorescent film on the face plate, causing a problem in the image such as luminance unevenness. Had occurred. (The arrow in FIG. 3
The mark indicates the scattering direction of the getter agent. It is considered that this absorbs the energy of the electrons applied to the fluorescent film and lowers the light emission efficiency of the fluorescent film. Further, since the getter agent attached to the fluorescent film is irradiated with the electron beam, there is also a problem that the residual gas is not adsorbed. Further, when the getter agent adheres to the fluorescent film, a problem such as deterioration of the fluorescent film occurs.

[0005]

A problem to be solved by the present invention is to prevent a getter agent from adhering to a fluorescent film on a face plate and to prevent a defect in an image . In addition, the currently installed getter holder,
An object of the present invention is to prevent the increase in the number of parts by also using the supporting structure of the shield.

[0006]

According to the present invention, in a cathode ray tube, a getter holder is disposed between a getter with a reflector and a face plate, and scattering of the getter agent is shielded by the getter holder. To prevent getter agent from adhering. In addition, the above problem was solved by providing an annular or cylindrical mechanism in the getter holder.

[0007]

FIG. 1 is a schematic sectional view of a first embodiment of a cathode ray tube according to the present invention. The cathode ray tube has a fluorescent film 2 made of a phosphor, a funnel 3 serving as a main body of the cathode ray tube, a support arm 4 of a getter holder, a getter holder (support structure for getter) 5, a getter 6,
It comprises a reflector 7 mounted on the inner diameter of the getter, an electron gun 8, and a stem 9 having a sealing portion. The getter holder 5 according to the present invention is located between the fluorescent film 2 and the getter 6 on the face plate, and is arranged so as to cover the gap between the inner wall of the funnel 3 and the reflector 7 mounted on the getter. With such a mechanism, when the getter agent is scattered in the direction of the face plate, the getter agent leaks from the reflector and is reflected on the inner wall of the funnel. Even if the getter agent scatters in the direction of the face plate, it is shielded by the getter holder. Getter holder
Can be shielded by the slope provided at the end of the
You. (The arrow in FIG. 1 indicates the scattering direction of the getter agent.)
For this reason, the image that occurs when the getter agent adheres to the fluorescent film
Failures are eliminated. In a cathode ray tube having a narrow space such as a small cathode ray tube, the mechanism as in the present invention is effective because the distance between the face plate and the getter is short.

[0008]

FIG. 2 is a schematic sectional view of a second embodiment of the cathode ray tube according to the present invention. The structure of the cathode ray tube is the same as that of the first embodiment, but an annular getter agent shielding portion 10 is provided on the opposite side of the getter support arm portion 4a of the getter holder 5a in the axial direction. Since the temperature of the getter at the time of scattering of the getter agent is about 800 ° C. at a high temperature, when the getter or the reflector is brought into contact with the inner wall of the funnel, there occurs a problem that the funnel made of glass is broken. However, the annular getter agent shielding portion 10 located far enough from the getter does not cause the above-described problem, and can be disposed in contact with the inner wall of the funnel. For this reason, even if the getter agent leaks and scatters in the direction of the face plate, it can be shielded by the annular getter agent shielding portion. (The arrow in FIG. 2 indicates the getter agent.
Indicates the scattering direction. ) Furthermore, the getter holder, by providing the shielding portion of the annular, New it is not necessary to provide a support structure of the shielding portions of the annular, the reduction in the number of components.

[0009]

As described above, in the cathode ray tube according to the present invention, the getter holder or the shielding part is arranged between the face plate and the getter, so that the getter is provided on the fluorescent film.
It is possible to eliminate defects in the image caused by the adhesion of the agent . Therefore, since the distance between the face plate and the getter can be designed close to each other, the total length of the cathode ray tube can be shortened.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a second embodiment of the present invention.

FIG. 3 is a schematic view of a cross section of a cathode ray tube according to the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Face plate 2 Fluorescent film 3 Funnel 4 Getter support arm part of getter holder 5 Getter holder 6 Getter 7 Reflector 8 Electron gun 9 Stem 10 Getter agent shielding part of getter holder

Claims (3)

(57) [Scope of request for utility model registration] 1. A funnel, a face plate having a fluorescent film at one end thereof, an electron gun further opposed to the other end, a getter with a reflector disposed at a funnel neck portion, and In a cathode ray tube in which a structure supporting the getter with a reflector is fixed to an inner surface of a funnel neck, a reflector for shielding the scattering of the getter agent is provided between the getter with the reflector and the face plate. > A cathode ray tube having a getter support structure. 2. The cathode ray tube according to claim 1, wherein a mechanism for shielding the annular or cylindrical getter agent from scattering is provided on the support structure of the getter with a reflector . 3. A support structure for the getter with a reflector.
The body is inclined at the end in the direction of the central axis of the funnel neck
A structure having an inclined portion,
Is a cathode ray tube according to claim 2.