JPH04118833A - High voltage processing method for cathode-ray tube - Google Patents

Abstract

PURPOSE:To effectively remove burr-like projections by causing electrical discharge to occur between the burr-like projections at the peripheral portions of a hole in a low-voltage electrode and a quasi-electrode inserted into a hole portion of an electrode applied with a positive high voltage, through application of a high voltage between the quasielectrode and the low-voltage electrode. CONSTITUTION:The vacuum vessel 33 is evacuated to a substantially wholly vacuum state. Thereafter, a high voltage of 40KV or so and an earth voltage are applied to a quasi-electrode 34 and a second grid member 15, respectively. At this time, since a high electric field is applied to burr-like projections 31 at the peripheral portion of a hole 28 of the second grid member 15, the field emission from the burr-like projections 31 collides against a distal end of the quasi-electrode 34 to cause the gaseous material adsorbed on the surface thereof to give forth or to cause metal vapor to generate from the quasi-electrode 34. Resultantly, electric discharge takes place in the vicinity of the projections 31 to effectively remove these projections 31. Then, an electron gun is taken out from the vacuum vessel 33 and, at the same time, the quasi-electrode 34 is drawn off. By sealing the electron gun into a glass bulb of a cathode-ray tube, assembling thereof is completed.

Description

[Detailed description of the invention]

[Industrial Field of Application 1] This invention relates to a high voltage treatment method for cathode ray tubes, which is applied, for example, to improve the withstand voltage characteristics of color cathode ray tubes. [Prior Art] Fig. 2 is a partially cutaway side view showing the general configuration of a color cathode ray tube. ) and a neck part (3), with an internal conductive film (5) on its inner and outer surfaces.
and an external conductive film (6). The F-oriented conductive part 1ll (51 extends to the inner surface of the neck part (3), and an insulating coating (7) is provided on a part of the funnel (2).
) is electrically connected to an anode terminal (8) provided covered by. (9) is an electron gun housed in the neck part (3). FIG. 3 is an enlarged longitudinal sectional view of the vicinity of the neck portion (3), and the electron gun (9) includes an anode (1)), a W5 grating (12
), 4th lattice (+31. 3rd lattice (14), 2nd lattice (
15), a bead glass (18), a cup-shaped body (19), and a bulb spacer (20) that hold the first grid (16) and cathode (17) electrodes together. The above anode (It) and I! The fourth grid (13) is connected to the connector (21A3), and high pressure is applied from the outside through the anode terminal (8), the internal conductive film (51tl+) and the valve spacer (20). It is connected to the third lattice (14) through a connector (2-1'll), and an auxiliary high voltage is applied from the outside through the lead #I (24^) planted on the stem (23). lattice (15), first lattice (
I6) and cathode (17) are separate connectors 12]C
1 and the lead wire (
24B), a voltage is applied from the outside. The operating voltage of the multi-step focusing electron gun is 9 KV for the third grating (14) and several +00 V for the second grating (15), so there is a voltage between the second grating (15) and the third grating (14). A voltage nearly twice that of a conventional pi-potential electron gun is applied. Figure 4 shows the third grating (I4), the second grating (+5) iS, and the first grating.

[16] In the enlarged view of the vicinity, R, G,
B cathodes (17) are arranged and these cathodes (1
7) has a cathode coating (25) applied to its tip, and a heater (26) is arranged inside. (28) and (29) are the second lattice (15)
) and the third grating (14), respectively.
This hole is formed to correspond to the hole (27) in 6). By the way, 1. In the F color cathode ray tube, the second grating (
Since the hole 128) of 15) is formed by punching with a press die, a pars-like protrusion (31) is formed around the hole (28) as shown in FIG.
Even if 31) is polished using a chemical, for example, it is often scratched by a jig or the like during assembly of the electron gun, and microprotrusions (31) are often present due to the scratches. moreover,
B a O (3
0) adheres to the circumferential surfaces of the protrusion (31) and hole (28). As mentioned above, a voltage of nearly 9 KV is applied between the second grid (I5) and the third grid (14) during operation of the electron gun, so around the hole (28) of the second grid (15). Field emission (32
) occurs. This field emission is
According to the ler-Nordheim relation, the protrusion (31
) is determined by the electric field multiplication coefficient β, which is determined by the shape of the tip of the tip, and the work function of its surface.
32) is released. In order to eliminate such field emissions (32), conventionally the stem (23) is placed in a highly insulating liquid or gas, and a high voltage of about 40 KV is applied from the lead wire (24A) to the third grid (14). high voltage processing was performed. In this case, the hole (
Since 291 is considerably larger than the hole (28) in the second grid (151), the field emission (32) from the paris-like protrusion (31) around the hole (28) in the second grid (15).
passes through the hole (29) of the third grid (14) and collides with the side of the third grid (14), as shown in Figure 5. -Author, "Vacuum discharge initiation simulation using cathode heating and anode heating theory"
According to the anodic heating theory described in , it is not possible to cause discharge in the vicinity of the Paris-like protrusion (31), and therefore, even if high voltage treatment is performed, the Paris-like protrusion (31) cannot be effectively removed. Problem to be Solved by the Invention 1 According to the conventional high-voltage treatment method for cathode ray tubes as described above, it is possible to remove BaO attached to the Paris-like protrusions (3) around the second grating (15) and the surface thereof. When a high voltage is applied between the second grating (15) and the third grating (14) in order to remove the
15), the diameter of the hole (28) in the second lattice (
The field emission (32) emitted from the paris-shaped protrusion (31) around the hole (28) in the third grid (15)
14), therefore, a forced discharge cannot be caused, and the parry-like protrusion (31) cannot be effectively removed. This invention was made to solve the above-mentioned problems, and it is a high-voltage treatment for cathode ray tubes that can effectively remove the pars-like protrusions that exist around the holes in the electrodes to which high positive voltage is applied. The purpose is to provide a method. ``Means for Solving the Problems J'' A method for high voltage treatment of a cathode ray tube according to the present invention provides a pseudo electrode in a hole of an electrode to which a positive high voltage is applied from an anode part of an electron gun before being sealed in a cathode ray tube. is inserted and the pseudo electrode is brought close to an electrode to which a low voltage is applied, and then a high voltage is applied between the pseudo electrode and the low voltage electrode with the electron gun in a vacuum state. [Function] According to the present invention, by applying a high voltage between the low voltage electrode and the pseudo electrode inserted into the hole of the electrode to which a positive high voltage is applied, the area around the hole of the low voltage electrode is reduced. A discharge is generated between the protrusion and the pseudo electrode, and the pariform protrusion is effectively removed. [Embodiment of the Invention] An embodiment of the present invention will be described below based on the drawings.This embodiment The structure of the color cathode ray tube to which this invention is applied is the same as that shown in Figs. 2 to 4, so a description thereof will be omitted. Fig. 1 shows a high voltage processing method for a cathode ray tube according to an embodiment of the present invention. 2 is an enlarged vertical cross-sectional view of the main parts shown in FIG. (31) is a pariform protrusion existing around the hole (28) of the second lattice (15), and (34) is inserted through the hole (29) of the third lattice (14) and its tip is inserted into the second lattice. (15). After the above preparation process, the air in the vacuum container (33) is evacuated to create an almost vacuum state, and then the manufactured electrode (34) is
), apply a high voltage of about 40KV to the second grid (15).
Apply earth voltage to. At this time, the second grid (15)
Since a high electric field is applied to the Paris-like protrusion (31) around the hole (28), the field emission emitted from the Paris-like protrusion (31) collides with the tip of the pseudo electrode (34), and its Gas adsorbed on the surface and furthermore, metal vapor is generated from the pseudo electrode (34), and due to the anode heating stage described above, a discharge occurs near the Paris-like protrusion (31), which causes the Paris-like protrusion (31) to can be effectively removed. Moreover, the pseudo electrode (34) can be placed quite close to the second grating (15). For example, the third lattice (1
4) and the second grating (15). This allows the applied voltage as a high voltage to be reduced to 1
Even at 0KV, it is possible to perform almost the same function as the conventional 40KV. Therefore, it becomes possible to process high voltage using a small and lightweight power supply, which is also advantageous in terms of safety. After the above processing steps, the electron gun is taken out from the vacuum container (33) and the pseudo electrode (34) is extracted, and then the electron gun is sealed in the glass bulb (4) of the cathode ray tube as in the conventional process. Then, the cathode ray tube is completed as specified. Note that, as the material for the pseudo electrode (34), a soft material such as aluminum is more advantageous than a soft material because it can cause discharge at a low applied voltage. Further, in the above embodiment, high voltage treatment was explained between the second grating (15) and the third grating (14), but the high voltage treatment may also be performed between the third grating (14) and the fourth grating (13). This can be applied to cases where the hole diameter of the electrode to which a positive high voltage is applied is larger than the hole diameter to which a lower voltage is applied. Further, in the above embodiment, high voltage processing of one electron gun was explained, but it is also possible to process multiple electron guns at the same time, for example, 50 to 100 electron guns, and in this case, workability can be extremely high. can. Further, in the above embodiment, a multi-step focus electron gun has been described, but the present invention can also be applied to other electron guns.

【Effect of the invention】

As described above, according to the present invention, for an electron gun, the hole diameter of the electrode to which a positive high voltage is applied is larger than the hole diameter to which a low voltage is applied. By reliably causing a discharge between the protrusions and pseudo electrodes that exist in the periphery,
The pariform projections can be effectively removed, and a highly reliable cathode ray tube can therefore be obtained.

[Brief explanation of the drawing]

FIG. 1 is an enlarged vertical sectional view of the main parts showing a high voltage processing method for a cathode ray tube according to an embodiment of the present invention, FIG. 2 is a partially cutaway side view showing the general configuration of a cathode ray tube, FIG. 3 is an enlarged vertical cross-sectional view of the vicinity of the neck of the cathode ray tube, FIG. 4 is an enlarged view of the vicinity of the second grid, and FIG. 5 is a vertical cross-sectional view showing a conventional high voltage processing method for the cathode ray tube. (9)...Electron gun, (14)...Third grating, (15
)...Second grid, +31)...Parid-like projections existing around the second grid holes, +32)-...Field emission, (33)...Vacuum vessel, +341-...
Pseudo electrode. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A step of inserting a pseudo electrode into the hole of the electrode to which a high positive voltage is applied from the anode part of the electron gun before being sealed in the cathode ray tube and bringing it close to the electrode to which a low voltage is applied; A method for high voltage processing of a cathode ray tube, comprising the steps of: placing an electron gun including the pseudo electrode in a vacuum state; and applying a high voltage between the pseudo electrode and the low voltage electrode.