JPS61237330A - Assembling method for electron gun for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To alleviate damage at the opposed surface of electrode with a simplified method and improve voltage resistance characteristic by executing the beading process in the assembling of electron gun using a rod type spacer between the electrodes. CONSTITUTION:A rod type spacer 23 having the circular section is used and a hole 12A elongated in the axial direction is formed at the area of core metal 12 where the spacer 23 is to be inserted. The spacer 23 is then inserted into the hole 12A through the longitudinal direction of electrode element and it is held by a fourth grid 6 and an upper third grid 5. Since the rod type spacer 23 is in the contact with the grids 6 and 5 at only a very narrow area, a foreign matter is little caught between the electrodes 5, 6 and spacer 23, the spacer 23 is a little rotated when it is pulled and thereby damage at the surface of electrodes 6, 5 is not severe. The rod type spacer 23 is well finished in the predetermined thickness and this spacer can be obtained only by cutting a hard steel wire. Moreover, it rotates only when it is held by the electrodes 5 and 6. Therefore, a little bending does not give any influence on the accuracy of interval and it can be formed economically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method of assembling an electron gun for a color cathode ray tube.

[Background of the invention]

In electron guns for color cathode ray tubes, assembly accuracy such as coaxiality and parallelism between the constituent electrodes not only affects the focus characteristics, but also the spacing accuracy and surface condition between the electrodes to which high voltage is applied. Affects voltage characteristics.

FIG. 1 is a side view of essential parts showing an example of an in-line electron gun of the pi-potential focusing type. In the figure, 1 is a first grid that includes a cathode (not shown) and controls the amount of electron beam by a signal voltage, 2 is a second grid that accelerates the electron beam, and 3 is a third grid that focuses the electron beam.
In the grid, lower third grid 4 and upper third grid 5
It is formed by combining. 6 is a fourth grid, and 7 is a multiform glass that insulates and supports each of the electrodes.

In such a configuration, when the color cathode ray tube operates, E
A high voltage of QV is applied to the first grid 11, about 700 V to the second grid, about 7 KV to the third grid 3, and about 25 KV to the fourth grid 6t. Therefore,
In particular, the third grid 3 and the fourth grid 6 have a large potential difference.
It is desirable that the distance between the However, the electrode spacing is set to be as narrow as about 1 m in order to prevent a shift in the convergence of the three electron beams due to changes in the inner wall potential of the color cathode ray tube to which the electron gun is attached.

The withstand voltage characteristics can be improved to a level that causes no practical problems by applying a high voltage of 50 to 60 KV to the fourth grid 6 during the manufacturing process of the color cathode ray tube.

However, if there is a defect such as a large scratch on the surface of the upper third grid 5 facing the fourth grid 6, even if high voltage treatment is applied, there will be a discharge during operation or electron emission from the defective part. However, problems such as unnecessary parts of the phosphor surface emitting light remain, resulting in defective color cathode ray tubes.

Such scratches on the upper third grid 5 occur during the beading process of electron gun assembly.

FIG. 2 shows a cross section of an electron gun equipped with the beading jig I disclosed in, for example, Japanese Utility Model Application No. 51-46256. In FIG. 1, supports IA and 6A are attached in advance to the first grid 1 and the fourth grid 61, respectively. Also, the lower third grid 4 and the upper third grid 5
The third grid 3 is assembled by welding and fixing the respective flange parts 4A and 5A in advance. Therefore, the plurality of core metals 12f set on the substrate 11, the fourth grid 6
, third grid 3, second grid 2 and first grid 1
13, 14, and 15 of a predetermined thickness are sandwiched between each electrode.
The grid 1 is held by pressurizing it from above with a presser bar 16.

The beading jig holding the electrodes in this manner is placed on a beading machine, and the multiform glass 7 heated to 1000 to 1200" C1 is pressed onto the support portion of each electrode. Next, the beading jig holds the electrodes in this manner. The beaded electron gun is removed from the beading jig, and then spacers 13 and 14 are
．． Pull out 15. From this, the electron gun shown in FIG. 1 is obtained.

However, there is a problem in that when the spacers 13, 14, and 15 are pulled out, scratches occur on the electrode surfaces. As described above, since scratches on the upper grass 3 grid 5 in particular have a large effect on the withstand voltage characteristics, the case where the spacer 13 is pulled out will be explained. As shown in FIG. 3, the spacer 13 is provided with a cut 13A that escapes the core 12 of a steel plate I of a predetermined width.
Both surfaces 13B in contact with the electrodes are polished smoothly.

By the way, before the spacer 13 is pulled out, the electrode spacing becomes narrower due to contraction of the multiform glass 7 due to cooling.
Strong force is required to remove the spacer 13. Therefore, if there is a minute protrusion on the top @3 grid 5# or if a minute foreign matter is attached to the surface of the top third grid 5 or the spacer 13, the top third grid 5# will be removed as shown in Fig. 4. There was a serious problem in that a scratch 5B was formed on the top surface of the spacer 5 by pulling out the spacer 13, which deteriorated the withstand voltage characteristics.

[Purpose of the invention]

An object of the present invention is to assemble an electron gun for a color cathode ray tube that can obtain a color cathode ray tube with excellent withstand voltage characteristics by preventing scratches on the electrode facing surface that occur during the beading process of the electron gun assembly as described above. The purpose is to provide a method.

[Summary of the invention]

According to one embodiment of the present invention, a rod-shaped spacer is used between electrodes to perform a beading process for assembling an electron gun. This reduces scratches when pulling out the spacer.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. Note that the same members ζ as in FIG. 2 are designated by the same reference numerals, and their explanations will be omitted. The present invention is directed to a plate-shaped spacer 13I shown in FIG.
Instead, a bar-shaped spacer 23 with a circular cross section is used.

Further, the core bar 12t has an axially long hole 12A formed at a location where the spacer 23 is inserted. Therefore, the spacer 23 is inserted into the hole 12A and passed through the electrode component in the longitudinal direction, and is sandwiched between the fourth grid 6 and the upper third grid 5.

Since the rod-shaped spacer 23 has a very small contact area with the fourth grid 6 and the upper third grid 5, the electrode 6.
5 and the spacer 23, and
Also, since the spacer 23 can be rotated slightly when being pulled out, the scratches on the surface of the electrode 6.5 will be minor. In addition, the rod-shaped spacer 23 can be used by simply cutting a steel wire of a predetermined thickness with a good surface finish and high hardness, such as commercially available piano wire, and can also be used between the electrodes 6.5 (by sandwiching it Therefore, slight bending does not affect the spacing accuracy and can be manufactured economically.

The parallelism of the electrode spacing due to the bar-shaped spacer 23i is regulated by the substrate 11 and core metal 121 of the beading jig, but if even higher precision is required, use A rod-shaped spacer 33 may be used. That is, each of the core metals 12F on both sides is provided with a long hole 12A, and each of these long holes 12AJ penetrates through the spacer 33 and is arranged parallel to the short diameter direction E of the electrode component. This further improves the parallelism between the electrodes, and also reduces scratches on the surface facing the electrodes as in the previous embodiment.

〔Effect of the invention〕

As is clear from the above description, according to the present invention,
A very simple method (this makes it possible to reduce scratches on the surface facing the electrodes and improve the withstand voltage characteristics of color cathode ray tubes).

[Brief explanation of drawings]

Figure 1 is a side view of the main parts of an electron gun for color cathode ray tubes, Figure 2
The figure is a sectional view of the main parts showing the conventional assembly method, Figure 3 is a perspective view of the spacer in Figure 2, and Figure 4 is an explanatory plan view showing the state of scratches on the electrode surface due to the spacer being pulled out in Figure 2. , FIG. 5 shows an embodiment of the assembly method according to the present invention,
tal is a side view of the main part, (b) is a front view of the main part, and FIG. 6 is a front view of the main part showing another embodiment of the assembly method according to the present invention. 5... Upper third grid, 6... Fourth grid, 7... Multiform glass, 12... Core metal, 23. 33... Rod-shaped spacer. Figure 2 Figure 3 Figure 4 Figure 5 (0) (b) Figure 6

Claims (1)

[Claims] A plurality of electrodes are fitted to a core metal, a spacer is sandwiched between each electrode, and each electrode is arranged at a predetermined interval, and a plurality of heated multi-form glasses are crimped to a support provided on each electrode. 1. A method of assembling an electron gun for a color cathode ray tube in which each electrode is insulated and supported, wherein at least one of the spacers is a rod-shaped spacer.