JPH06260102A - Electron gun structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent deterioration of electrical characteristics due to displacement of the first grid electrode in the direction of the central axis. A cathode including a heater and a first grid electrode positioned in a direction of emitting electrons from the cathode are provided, and the cathode and the first grid electrode are supported by a glass bead with their central axes aligned with each other. In addition, the cathode and the first grid electrode are supported by the glass beads through the support members extending orthogonally to the central axis, respectively. In the electron gun assembly, the cathode is supported by the glass beads. The support material was provided with a cushioning means against elongation due to thermal expansion.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to electron gun assemblies.

[0002]

2. Description of the Related Art An electron gun assembly incorporated in a cathode ray tube basically comprises a cathode that emits electrons by heating a heater and an electron beam that is arranged in the electron emission direction of the cathode and irradiates a fluorescent screen. And an electronic lens that focuses the light.

A first grid electrode is arranged between the cathode and the electron lens in order to control the amount of electrons emitted from the cathode.

The cathode, the first grid electrode,
The electrodes constituting the electron lens are supported by a common bead glass with their central axes aligned.

That is, the cathode containing the heater is
The tip portion of the support member that is fixed to the cathode and extends in the direction orthogonal to the central axis is embedded in the bead glass, thereby being fixed to the bead glass.

The first grid electrode arranged adjacent to the cathode is made of a plate material having a through hole through which electrons pass, and the plate material extends in a direction orthogonal to the central axis to form a support material. And the tip of this support material is embedded in the bead glass, thereby being fixed to the bead glass.

[0007]

However, in the electron gun assembly constructed as described above, the heat generated by the heater is conducted to the support material of the heater and expands the support material during its operation. .

For this reason, the bead glass is pushed in the radial direction, and accordingly, the bead glass is the first.
It will pull the grid electrode.

In view of the above, the first grid electrode is usually formed with a bent portion in the vicinity of the portion embedded in the bead glass, and the bent portion prevents the force from reaching the vicinity of the central axis. It has become.

However, creep of metal occurs due to heat and stress when viewed for a long time. Therefore, the bending of the bent portion due to the pulling of the first grid electrode of the bead glass causes a slight deviation in the central axis direction in the vicinity of the central axis, which changes the electrical characteristics (cutoff voltage). The problem was found.

Therefore, the present invention has been made under such circumstances, and an object of the present invention is to prevent the deterioration of the electrical characteristics due to the displacement of the first grid electrode in the central axis direction. It is to provide the electron gun structure.

[0012]

In order to achieve such an object, the present invention basically comprises a cathode containing a heater and a first grid electrode positioned in the electron emission direction from the cathode. And at least the cathode and the first grid electrode are supported by the glass bead with their central axes aligned, and the cathode and the first grid electrode are supported by the glass bead at right angles to the central axis. In an electron gun assembly formed through an extending support material, the support material for supporting the glass beads of the cathode is provided with a buffering means against expansion due to thermal expansion.

[0013]

The thus constructed electron gun assembly has a structure in which a buffer member for supporting the glass beads of the cathode is provided with a buffering means against expansion due to thermal expansion.

Therefore, even if the heat generated by the heater is conducted to the support material of the heater to expand the support material during its operation, the force due to the expansion is buffered by the buffer means. , There is no need to push the bead glass in the radial direction.

Therefore, the pulling of the first grid electrode by the bead glass is eliminated, the vicinity of the central axis of the first grid electrode is displaced in the central axis direction, and the electrical characteristics (cutoff voltage) change. That will disappear.

From this, it is possible to prevent the deterioration of the electrical characteristics due to the displacement of the first grid electrode in the central axis direction.

[0017]

2 is a block diagram showing an embodiment of a color cathode ray tube to which the electron gun assembly according to the present invention is applied.

In FIG. 1, there is a glass envelope 1, and a phosphor screen 3 is formed on the inner wall of a face plate portion 2 of the glass envelope 1. The phosphor screen 3 is formed by alternately coating stripes of phosphors of three colors (R, G, B).

An electron gun assembly 30 is arranged in the neck portion 22 of the glass envelope 1 so as to face the fluorescent screen 3.

The electron gun assembly 30 is composed of red (G), green (G), and blue (B) electron guns.

One of the electron guns is a cathode (cathode) 6, a first grid electrode 9, a second grid 10, electrodes 11, 12 and 13 constituting a front lens, a focusing electrode 13 constituting a rear lens, The shielding cups 15 are arranged one after another with their central axes aligned. The same configuration is adopted in other electron guns, and the above-mentioned electrodes and the like are integrally formed with electrodes having the same function in other electron guns.

A voltage is applied to each of the electrodes and the cathode 6 which are integrally formed as described above via the stem pin 23, and the cathode 6 is applied by such a voltage application.
An electron beam emitted from the phosphor screen 3 is to be irradiated on the phosphor screen 3 with a predetermined beam diameter.

A shadow mask 4 is arranged on the side of the fluorescent screen 3 which faces the electron gun structure 30. The electron beams from the respective electron guns are focused on the surface of the shadow mask 4 and simultaneously overlap each other. Has become.

That is, each electron beam is adapted to be color-selected by the shadow mask 4, and only the component for exciting and emitting the phosphor of the color corresponding to each electron beam of the shadow mask 4. It reaches the phosphor screen 3 through the opening.

In order to scan the fluorescent screen 3 with such an electron beam, an external magnetic deflection yoke 16 is provided on a part of the outer surface of the glass envelope 1.

1 (a) and 1 (b) show the above-mentioned cathodes 6, 7, 8 and the first grid electrode 9, and these cathodes 6, 7, 8 and the first grid electrode 9 are made of bead glass. 25 is an explanatory diagram showing a configuration supported by 25. FIG. Here, FIG. 11A is a side view, and FIG. 11B is a sectional view taken along line Ib-Ib of FIG.

First, in FIG. 1 (a), there is a tubular body 32 having a pellet 31 at one end, and a heater is incorporated in this tubular body 32 to form the cathodes 6, 7, and 8. ing.

The cathodes 6, 7, and 8 are cathodes for red (G), green (G), and blue (B), respectively, and are arranged in parallel.

A plate material is adhered to each cathode 6, 7, 8 at its side surface, and the plate material extends in a direction orthogonal to the central axis to form support members 6A, 7A, 8A. 6A, 7A, 8A tips are the bead glass 2
By being embedded in 5, the bead glass 25 is fixed.

Then, each of these supporting members 6A, 7A, 8A
In each of the above, notches 6B, 7B, 8B are formed in the vicinity of being embedded in the bead glass 25.

These notches 6B, 7B and 8B serve as a buffering means against elongation due to thermal expansion, and serve to alleviate the transmission of force to the glass beads 25.

Further, the first grid electrode 9 is arranged in the direction of emission of electrons from the cathodes 6, 7, 8 so that the cathodes 6, 7,
It is arranged adjacent to No. 8.

The first grid electrode 9 is made of a plate material having through holes through which electrons pass, and the plate material extends in a direction orthogonal to the central axis to form a support material 9A. It is fixed to the bead glass 25 by embedding the tip thereof in the bead glass 25.

Further, the bead glass 25 of this support material 9
A bent portion x that is bent at a right angle is formed in the vicinity of the embedded portion, and a force (a force from the glass bead 25) does not reach the vicinity of the central axis due to the bent portion x.

The planar shape of the first grid electrode 9 is
It is as shown in FIG. 3, which is a sectional view taken along line III-III in FIG.

According to the electron gun assembly of this embodiment,
In particular, the support members 6A, 7B, 8c for supporting the glass beads 25 of the cathodes 6, 7, 8 are provided with notches 6B, 7B, 8B as buffer means against expansion due to thermal expansion.

Therefore, during the operation, the heat generated by the heater is generated by the support members 6A, 7A of the cathodes 6, 7, 8.
Even if the support material 6A, 7A, 8A is conducted to 8A and expands, the force due to the expansion is buffered by the buffer means, and the bead glass 25 is not pushed in the radial direction.

Therefore, the first by the bead glass 25
The grid electrode 9 is no longer pulled,
When the bent portion x of the first grid electrode 9 changes from the right angle state to the acute angle state, the portion near the central axis of the first grid electrode 9 is not displaced in the central axis direction.

Therefore, the electrical characteristics (cutoff voltage) will not change.

From this, it is possible to prevent the deterioration of the electrical characteristics due to the displacement of the first grid electrode 9 in the direction of the central axis.

In the above-mentioned embodiment, each cathode 6, 7,
The cutouts 6B, 7B, 8B are provided as buffer means in the support members 6A, 7A, 8A of No. 8, but the present invention is not limited to this, and the point is that buffer means for extension by thermal expansion is provided It goes without saying that it is all right.

[0042]

As is apparent from the above description,
According to the electron gun assembly of the present invention, it is possible to prevent the deterioration of the electrical characteristics due to the displacement of the first grid electrode in the central axis direction.

[Brief description of drawings]

1A and 1B are cathodes 6 shown in FIG.
FIGS. 7A and 7B are diagrams showing a portion of the first grid electrode 9, and FIG. 7A is a side view, and FIG. 9B is a sectional view taken along line Ib-Ib of FIG.

FIG. 2 is a configuration diagram showing an embodiment of a color cathode ray tube to which the electron gun assembly according to the present invention is applied.

3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

6, 7, 8 ... Cathode, 6A, 7A, 8A ... Supporting material, 6
B, 7B, 8B ... Notch, 9 ... First grid electrode, 25
... glass beads.

Front page continuation (72) Inventor Shunji Saito 3300, Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Devices Division

Claims (1)

[Claims] 1. A glass bead having at least a cathode including a heater and a first grid electrode positioned in a direction of emitting electrons from the cathode, wherein the cathode and the first grid electrode have their central axes aligned with each other. In the electron gun assembly, the cathode and the first grid electrode are supported on the glass bead by way of supporting members extending orthogonally to the central axis. An electron gun assembly characterized in that the support material to be formed is provided with a buffering means against expansion due to thermal expansion.