JPH0547313A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To stably provide a color cathode-ray tube in which inferior initial emission and inferior withstand, voltage characteristics much less occur. CONSTITUTION:The amount of contaminant substances deposited on the surfaces of metal parts constituting an electron gun 11 used in the tube, metallic members for use in a magnetic shield 6, and metallic members for use in a shadow mask 5 is determined to range from 10<-6> to 10<-10>g in terms of chlorine, from 10<-5> to 10<-7>g in terms of phosphorus, from 10<-6> to 10<-10>g in terms of carbon, and from 1 to 50nm in terms of the contamination depth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube used for color image display, and more particularly to a color cathode ray tube in which initial emission defects, withstand voltage defects and the like are extremely small.

[0002]

2. Description of the Related Art A cathode ray tube used for color image display is composed of a panel forming an image screen, a neck tube accommodating an electron gun, and a funnel connecting the panel and the neck tube, and a cone portion on the outer surface of the funnel. Is equipped with a deflecting device for scanning an electron beam emitted from an electron gun on a fluorescent screen formed by coating on the inner surface of the panel.

The electron gun housed in the neck tube is provided with various electrodes such as a cathode electrode, a control electrode, a focusing electrode and an accelerating electrode, and an electron beam from the cathode electrode is modulated by a signal applied to the control electrode. A desired cross-sectional shape and energy are applied through the focusing electrode and the accelerating electrode so that the fluorescent surface is bombarded. On the way from the electron gun to the fluorescent screen, the electron beam is deflected in the horizontal direction and the vertical direction by the deflecting device provided on the cone portion on the outer surface of the funnel to form an image on the fluorescent screen. (JP Sho
59-215640).

[0004]

In the conventional color cathode ray tube as described above, an electron gun consisting of metal parts and members, a magnetic shield, a shadow mask, etc. are mounted in the tube, and these metal parts and metal members are , The lubricating oil normally used in press molding is washed and removed with an organic solvent in advance,
Further, cleaned products that have been subjected to various heat treatments are used, but among the products that have undergone similar cleaning and heat treatments, some that impair the initial emission characteristics or some that deteriorate the withstand voltage characteristics are observed. There was something.

An object of the present invention is to solve the problems of the prior art and to provide a stable color cathode ray tube in which initial emission defects, withstand voltage characteristic defects and the like are extremely small.

[0006]

Means for Solving the Problems The above-mentioned object is to determine the amount of contaminants adhering to the surface of metal parts, magnetic shield metal members and shadow mask metal members constituting an electron gun used in a tube, with respect to chlorine. ⁶ to 10 to ¹⁰ g, sulfur 10 to ⁵ to 10 to ⁷ g, carbon 10 to ⁶ to 10 to ¹⁰ g
It can be achieved by setting the range.

Further, it is desirable that the contamination depth of the contaminants adhered to the surfaces of the above-mentioned metal parts and members is in the range of 1 to 50 nm from the surface.

[0008]

The above conclusions are that optical analysis of the cathode surface of the color cathode ray tube with initial emission failure, microscopic observation of defective products withstand voltage characteristics, and samples of various pollutant species and pollutant amount for each of the above metal parts and members. It is obtained as a result of a cathode ray tube mounting confirmation experiment conducted using the above.

That is, the presence of chloride and / or sulfide on the surface of the electron-emitting substance is recognized in the cathode of the color cathode ray tube having a poor initial emission.
In confirmation of cathode ray tube mounting using parts with various levels of contamination, if parts with pollution levels above the above range are used, the frequency of occurrence of defective initial emission will be high, whereas if the range below or below It was confirmed that the initial emission failure hardly occurred in the sample using the parts with the pollution degree.

Further, in the color cathode ray tube having a poor withstand voltage characteristic, the presence of minute whiskers was recognized inside the tube or on the surface of the metal part. For example, in FIG. 2, minute whiskers 13 generated in the cross section of the electron beam passage opening 12 of the shadow mask, minute whiskers 14 generated in the particles of the metal for the shadow mask,
Small whiskers formed at grain boundaries of metal for shadow mask 15
Indicates. Further, FIG. 1 shows an enlarged view of the electron beam passage opening portion of FIG. It has been confirmed that this minute whisker occurs remarkably when the amount of carbon contamination is large, and the withstand voltage failure is caused by the whisker causing discharge when a high voltage (25 to 35 kV) is applied to the electron gun. It is supposed to occur. It should be noted that the minute whiskers are generated when the impurities are present on the surfaces of the metal parts and members, and the crystals become abnormally grown as the nuclei of the impurities during the heat treatment in the cathode ray tube manufacturing process.

It is difficult to detect the surface contamination degree in the above range by a conventional analysis method, but the element species, size, and number of the surface contamination substance are the scanning type with an X-ray analyzer. By using an electron microscope (SEM-EDX, particles with a diameter of 0.2 μm or more can be discriminated from constituent elements), the contaminant distribution in the surface depth direction can be measured by a secondary ion mass spectrometer (SIMS, sensitivity 0.1
By using a × ¹⁰ ~ 10 g), and the amount of contamination carbon laser Raman spectrum (laser-Raman spectrum, the analysis of the sensitivity 0.5 × ¹⁰ ~ 10 g), could be possible.

[0012]

EXAMPLES The color cathode ray tube of the present invention will be specifically described below with reference to examples.

FIG. 3 is a schematic configuration diagram showing an embodiment of the present invention, in which 1 is a face plate panel portion, 2 is a funnel portion, 3 is a neck portion, 4 is a fluorescent surface (screen), 5
Is a shadow mask, 6 is a magnetic shield, 7 is a deflection yoke, 8 is an electron beam, and 11 is an electron gun.

Although not shown, an inner conductive film made of graphite or the like is deposited on the inner surfaces of the funnel portion 2 and the neck portion 3. The conductive film is titanium dioxide in addition to graphite for the purpose of arc suppression. The resistance value is controlled including the above. The conductive film electrically connects a high voltage terminal (not shown) to the electron gun 11.

Therefore, among the parts constituting the color cathode ray tube, in particular, the metal parts forming the electron gun, the metal member for the magnetic shield, and the metal member for the shadow mask are made into samples having respective contamination levels. The respective combinations were mounted and mounted in the cathode ray tube, and the withstand voltage characteristics and the initial emission characteristics were tested. In this case, the pollution degree of each part and member is measured by vacuum deposition of silver (Ag) on the surface of each part and member for chlorine and sulfur.
m), heat-treated in air at 450 ° C for 30 minutes, and the formed silver chloride (AgCl) and silver sulfide (Ag ₂ S) were detected by the SEM-EDX method and SIMS method described above. It was detected by the laser Raman method. The sample of the contamination distribution in the depth direction was prepared by ion implantation.

As a result of the above-mentioned test, in the case of using a combination of parts having a pollution degree of the above range or higher, the withstand voltage failure and the initial emission frequently occur, whereas the pollution of the range or lower is mentioned. The result was that in the case of the combined use of several parts, these defects were not recognized at all.

[0017]

As described above, by using the color cathode ray tube as the color cathode ray tube having the constitution of the present invention, the problems of the prior art can be solved and the initial emission defect, the withstand voltage characteristic defect, etc. can be solved. It was possible to provide a color cathode-ray tube in which the occurrence of

[Brief description of drawings]

FIG. 1 is an enlarged view of an electron beam passage opening portion of a shadow mask of a color cathode ray tube.

FIG. 2 is a partially enlarged view of a shadow mask of a color cathode ray tube.

FIG. 3 is a cutaway sectional view of a color cathode ray tube.

[Explanation of symbols]

1 ... Panel part, 2 ... Funnel part, 3 ... Neck part, 4 ...
Fluorescent screen, 5 ... Shadow mask, 6 ... Magnetic shield, 7 ...
Deflection yoke, 8 ... Electron beam, 11 ... Electron gun, 12 ... Electron beam passage opening of shadow mask, 13, 14, 15 ... Whiskers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromi Kawagoe 3300 Hayano, Mobara-shi, Chiba Hitachi Mobara Plant, Inc. (72) Inventor Shigeru Wakana 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara Plant, Ltd.

Claims (1)

[Claims] 1. An exhausted envelope including a face plate panel portion, a neck portion, and a funnel portion connecting these portions to each other, and a color phosphor on an inner surface of the face plate panel portion. A screen is formed, a shadow mask for color selection is arranged apart from this screen, and an electron gun for generating three electron beams at the neck portion and projecting them toward the screen is mounted. In a color cathode ray tube which is inserted and in which a magnetic shield is formed along the inner surface of the funnel portion, of the metal parts constituting the electron gun used in the tube, the metal member for magnetic shield and the metal member for shadow mask The amount of pollutants adhering to the surface is about 10 to ⁶ to 10 for chlorine.
¹⁰ g range, 10 to ⁵ to 10 to ⁷ g range for sulfur, 10 to ⁶ to 10 to ¹⁰ g range for carbon, and the contamination depth of the contaminants adhering to the surfaces of the above metal parts and components from the surface. 1-50 n
Color cathode ray tube characterized by being in the range of m.