JPS6372038A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To improve withstand voltage characteristic and eliminate generation of sparks by specifying the amount of foreign matter on an electron gun to be sealed in an envelope. CONSTITUTION:Foreign matter attached on an electron gun to be sealed in an envelope 10 is controlled to be particles of 1-100mum in diameters and 100-9,000 in number. As a method to control the amount of the attached foreign matter, the third grid 3 through the sixth grid 6 are immersed in washing liquid after the electron gun is assembled to be washed while being subjected to ultrasonic irradiation. At this washing, the number and the particle diameters of the foreign matter particles be removed are measured, and they are washed so as to make the remaining foreign matter particles to be 1-100mum in diameters and 100-9,000 in number. After the washing, further electron guns by sampling are immersed in washing liquid to be subjected to ultrasonic washing to confirm that foreign matter particles removed are 100-9,000 in number and 1-100mum in diameters. By this method, withstand voltage characteristic can be improved and a CRT in which no spark is generated is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a cathode ray tube E.

[Conventional technology]

In a cathode ray tube, for example, a color cathode ray tube (hereinafter referred to as a color picture tube) used in a color TV, a high voltage of 20-odd KV or more is applied as an anode voltage, and a focus voltage is about a fraction of the anode voltage. Further, a voltage of zero to several hundred volts is applied to each of the electric currents.

For such color picture tubes, as shown in US Pat. No. 3,556,627, measures are taken to clean the electron gun before it is enclosed in the envelope. .

As another method, each electrode part constituting the electron gun is press-molded and then cleaned, and then the electron gun is assembled in a 11-room, and after that, the electron gun is immersed in a cleaning agent. A method of cleaning the electron gun by irradiating it with ultrasonic waves and cleaning it has been proposed.

Furthermore, after enclosing an electron gun in the envelope and sealing it vacuum-tight, a high voltage is applied to a predetermined electrode E to eliminate the enclosed foreign matter and minute protrusions on the electrode (spot knocking). ) has been proposed.

[Problem that the invention seeks to solve]

However, even if an electron gun is cleaned using the conventional method described above, sparks are generated during operation due to foreign matter adhering to the gun, causing problems in terms of voltage resistance characteristics.On the other hand, if the cleaning progresses too much, There was a problem in that it interfered with spot knocking.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cathode ray tube that has improved voltage resistance characteristics and does not generate sparks.

[Means for solving problems]

The present invention achieves the above object by controlling the amount of foreign matter contained in the envelope of the electron gun.

[Effect]

By identifying the bag of foreign matter that adheres to the electron gun, it is possible to prevent sparks induced by the foreign matter 1, and to control the spot knocking process from the minute foreign matter.

〔Example〕

Hereinafter, the present invention will be explained with reference to the drawings and examples shown. First, FIG. 1 is a side view showing an embodiment of the cathode ray tube of the present invention, and FIG. 2 is an enlarged sectional view of the main part of FIG. 1. In the figure, K
is Kando, 1 to 6 are 1st to 6th grid,
7 is a contact spring, 8 is an inner conductive film, 9 is a neck tube, 10 is an envelope, 11 is a shield cup placed between the sixth grid 6 and the contact spring 7, 12
(The light surface 13 is a shadow mask, an anode voltage is applied to the sixth grid 6 through the inner conductive film 8 and the contact spring 7, and each electrode of the third grid 3 and below is connected from the stem side.) A predetermined voltage is applied to each, and the fifth grid 5 is connected to the third grid 3, and the fourth grid 4 is connected to the sixth grid 6 within the tube. 1 to 10
The adhesion amount is controlled at 100 to 9,000 particles with a particle size of 0 μm.

As a method of controlling the amount of foreign matter adhering, it is of course possible to treat the electrode itself, but after assembling the electron gun, the third grid 3 to the sixth grid 6 are immersed in a cleaning solution and cleaned while irradiating them with ultrasonic waves. I do. The number and particle size of the attached foreign matter removed during this cleaning is measured, and the remaining foreign matter is determined to have a particle size of 1 to 100.
Wash so that the number of particles is 100 to 9000 μm. Note that the cleaning liquid used is one with a composition containing pure water and an organic solvent, and the cleaning time differs depending on the structure of the electron gun.
If the structure is as shown in the figure, cleaning may be performed for about 10 minutes.

After cleaning, remove the electron gun by immersing it in fresh cleaning solution and performing ultrasonic cleaning, and confirm that the number of foreign particles removed is 100 to 9,000 particles with a particle size of 1 to 100μ. .

The foreign matter removed by this cleaning and the remaining attached foreign matter are inorganic, metallic, and organic foreign matter, and exhibit ionic and nonionic properties with respect to the cleaning solution.

Cathode ray tube 1 consisting of such structure and 3rd flp
i As a result of measuring the leakage current with the wiring shown, the fourth
As shown in Figure I, compared to the characteristics a1 of the conventional structure, in the present invention, as shown in the characteristics, the leakage current is less than W or less, and the withstand voltage is improved by about 2 to 8 KV. In addition, in the case where the amount of foreign matter attached was further reduced than that of the present invention, there was a problem in the spot knocking process, and the tendency was almost the same as characteristic a. The square ratio is taken, and the horizontal axis is the reciprocal of the applied voltage.As is clear from this figure, the characteristic C of the present invention is significantly improved compared to the characteristic fid of the conventional structure. is being measured.

In addition, in the above-mentioned embodiment, one example having grid electrodes from the first grid to the sixth grid was explained.
Of course, the present invention can be similarly applied to other electrode structures.

〔Effect of the invention〕

As described above, according to the present invention, the leakage current can be reduced by the conventional structure f.
This can be reduced by half compared to the previous model, and there is no generation of sparks, making it possible to improve the withstand voltage characteristics.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the cathode ray tube of the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, FIG. 3 is a leakage current measurement circuit diagram, and FIGS. 4 and 5 are It is a characteristic diagram. 1 to 6...1st to 6th grid, 8...Inner αI
! Membrane in J conductor, 9... neck tube, 10...
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Claims (1)

[Scope of Claims] 1. A cathode ray tube having an envelope and an electron gun enclosed in the envelope, in which 1 to 10 particles attached to the electron gun are provided.
A cathode ray tube comprising 100 to 9,000 foreign particles with a particle size of 0 μm. 2. The cathode ray tube according to claim 1, wherein the foreign matter is composed of an inorganic foreign matter, an organic foreign matter, and a metallic foreign matter, and exhibits ionic and nonionic properties with respect to a cleaning agent.