JPH0733357Y2 - Cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an improvement of a microminiature cathode ray tube used as, for example, a viewfinder of a video device or a television camera.

[Prior Art] A cathode ray tube for reproducing an image in a video device or the like has an electron gun housed in its neck, and an electron beam from this electron gun is deflected horizontally and vertically by a deflection coil on the outer periphery of the neck. Then, the one that scans on the fluorescent part of the face part,
It is common. The electron gun housed in this neck is a cathode that emits electrons when heated by a heater (filament), one or more grids that converge the electrons, and images of the converged intersections, and the face portion. It is equipped with a converging lens system that can be connected on the fluorescent screen, and the cathode and the first grid are integrally assembled, for example, in the structure shown in FIGS.

That is, in FIGS. 4 to 5, 1 is a grid hole 1a in the center.
The first grid 2 having a cap shape is an electrically insulating cathode support fitted inside the first grid 1, and is fixed by a retainer 3 from below so as not to come out. Then, the pair of leads 4 attached to the support body 2,
A filament 5 is stretched between the upper ends of 4 and an electron emissive material is applied to the central portion thereof to form a cathode 6. Reference numeral 7 is a spacer for keeping the distance between the first grid 6 and the cathode 6 (hereinafter, referred to as GK distance) constant, which is omitted in FIG.

However, in this assembly structure, when the side wall 1b of the first grid 1 is cylindrical as shown, the circular cathode support 2 that fits the side wall is fitted to the side wall 1b of the first grid. Since the cathode support 2 having such a shape is used and the cathode support 2 is tightly fitted over the entire circumference so that no gap is formed, the following problems occur.

[Problems to be solved by the invention]

That is, when the mounting positions of the leads 4, 4 on the cathode support 2 are displaced in the direction perpendicular to the direction in which the filament 5 is stretched or the leads 4, 4 are bent in the same direction, the cathode support 22 is directly moved to the first position. If one grid 1 is fitted and fixed, as shown in FIG. 4, the cathode 6 will not be located immediately below the grid hole 1a, but if such a positional deviation of the cathode 6 occurs, as described above, In the assembly structure in which the conforming cathode support 2 is tightly fitted to the first grid 1, it is not possible to appropriately move the cathode support 2 inside the first grid 1 to correct the positional deviation of the cathode 6. There was a problem.

Since such a problem meets the recent demand for ultra-miniaturization of cathode ray tubes, when the grid hole 1a has a hole diameter of about 0.2 mm and a coiled filament 5 having a coil diameter of about 0.1 mm is stretched, Since it requires a considerably high degree of accuracy, it is important and its early solution is desired.

[Means for solving problems]

In order to solve the above problems, the present invention provides a cathode ray tube having a single electron gun in a neck portion, in which a cathode support fitted in a first grid having a grid hole in the center of the electron gun is provided in the center thereof. At both ends in the extending direction of the filament in which the cathode is formed on the part, the side wall of the first grid is joined and fixed, and a clearance is provided between the side wall of the first grid and the cathode support except for this joining and fixing part. It is characterized by being provided.

[Action]

According to the cathode ray tube having such a configuration, the cathode support fitted in the first grid is first joined and fixed to the side wall of the first grid at one end portion in the filament tensioning direction, and then the one of the joints is joined. The cathode support is rotated within the clearance around the fixed end, and the cathode is positioned so that the cathode is located directly below the grid hole. Then, the other end of the cathode support is located. Can be assembled by being fixedly bonded to the side wall of the first grid, so that the cathode will not be displaced.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partially cutaway side view of a cathode ray tube according to an embodiment of the present invention, FIG. 2 is a partially cutaway plan view showing an assembly structure of a cathode and a first grid, and FIG. It is sectional drawing of a structure.

The cathode ray tube 8 of this embodiment has an inside of the neck portion 8a,
A single electron gun is housed, and a deflection coil 10 and a centering magnet 11 are fitted and fixed to the outer periphery of the neck portion 8a on the funnel portion 8b side through a support body 12, and an electron beam from the electron gun 9 is emitted. Is deflected in the horizontal and vertical directions by the deflection coil 10 to scan the fluorescent surface 8d of the face portion 8c, and the centering magnet 11 causes the spot position on the fluorescent surface 8d of the electron beam during non-deflection,
The center of the fluorescent screen 8d can be corrected.

The feature of this cathode ray tube lies in the assembly structure of the cathode support of the electron gun 9 and the first grid. That is, the electron gun 9 itself has substantially the same structure as that of the conventional one, and the cathode 14 that emits electrons when heated by the filament 13, the single or multiple grids 15 that converges the electrons, and the A convergent lens system 16 for further forming an image of the converged intersecting points on the face fluorescent surface 8d is provided, and the cathode support 17 and the first grid 15 thereof are as shown in FIGS. It has a simple structure and is integrally assembled, which is significantly different from the conventional structure shown in FIGS.

The assembly structure of FIGS. 2 to 3 will be described in detail.
This is a cap-shaped first grid having a grid hole 15a in the center, and an electrically insulating cathode support 17 is fitted inside the cylindrical side wall 15b of the first grid 15.
The support 17 has an elliptical planar contour, and a metal band 17a is attached to the outer periphery of the support 17 integrally with glass or by brazing. Further, the cathode support 17 has a pair of leads 18, 18 on the center line in the major axis direction, and a coiled filament 13 is stretched between the upper ends of both the leads 18, 18. The cathode 14 is formed by applying an electron emissive substance such as carbonate to the central portion thereof.

The cathode support 17 is spot-welded to the side wall 15b of the first grid 15 at both ends in the tension direction of the filament 13 (that is, in the major axis direction), and is joined and fixed at both ends. Clearances 19 and 19 are formed between the side wall 15b of the first grid and the metal band 17a of the cathode support 17 except for the joint fixing points P1 and P2.

In addition, 20 is an insulating spacer interposed between the cathode support 17 and the first grid 17, and is for determining the GK interval.

With the above-described assembly structure, the cathode support 17 fitted in the first grid 15 is provided with the metal strip 17a at one end P1 in the filament tensioning direction and the side wall 15b of the first grid.
, Spot-welded and joined and fixed, and then the cathode support 17 is rotated in the direction of arrow AB within the range of the clearance 19 around the joined fixed end P1 as a center,
14 is so positioned as to face the position directly below the grid hole 15a, and is accurately aligned.After that, at the other end P2 of the cathode support 17, the metal strip 17a is attached to the side wall 15b of the first grid.
Assembly can be performed by spot welding and joining and fixing. Therefore, the mounting positions of the leads 18 and 18 are deviated from the tension direction of the filament 13 in the direction at right angles,
Even if the leads 18 and 18 are bent in the same direction, the cathode 14
There will be no misalignment. Needless to say, various other means such as laser can be adopted as means for spot welding.

Since the clearance 19 gives the cathode support 17 a degree of freedom of rotation in order to correct the positional deviation of the cathode 14 as described above, it is not necessary to provide a very large clearance. For example, grid hole 15a
When the coiled filament 13 having a hole diameter of about 0.2 mm and a coil diameter of about 0.1 mm is stretched, it is sufficient to set the maximum clearance to about 0.2 mm.

Although the present invention has been described above with reference to one embodiment, the present invention is not limited to this embodiment.For example, the cathode support 17 may have a shape other than an elliptical shape, Needless to say, various modifications such as a straight thin wire can be allowed for the filament 13.

[Effect of device]

As is clear from the above description, the cathode ray tube of the present invention is
Even if the mounting position of the lead that stretches the filament is misaligned or the lead is bent, it has the effect of accurately aligning the cathode with the opposing position of the grid hole. Accordingly, it is possible to easily realize ultra-miniaturization of the cathode ray tube (for example, a neck portion having a diameter of about 6 mm).

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a cathode ray tube according to an embodiment of the present invention, FIG. 2 is a partially cutaway plan view showing an assembly structure of a cathode support and a first grid, and FIG. FIG. 4 is a cross-sectional view of the assembly structure, FIG. 4 is a partially cutaway plan view showing an assembly structure of a conventional cathode support and a first grid, and FIG. 5 is a cross-sectional view of the structure. 8 ... Cathode ray tube, 8a ... Neck part, 9 ... Electron gun, 13 ...
… Filament, 14… Cathode, 15… First grid, 15a… Grid hole, 15b… First grid sidewall,
17 …… Cathode support, 19 …… Clearing, P1, P2…
… Joining and fixing points.

Claims (1)

[Scope of utility model registration request] 1. A cathode ray tube having a single electron gun housed in a neck portion, wherein a cathode support fitted in a first grid having a grid hole in the center of the electron gun and a cathode in the center portion Both ends of the formed filament in the tension direction are bonded and fixed to the side wall of the first grid, and a clearance is provided between the side wall of the first grid and the cathode support except for this fixed position. Characteristic cathode ray tube.