JPS58186131A - Crt and its production method - Google Patents

Abstract

PURPOSE:To prevent a spark from occurring between a low voltage electrode and a bulb neck portion by forming a thin and high resistance film by deposition on a region inside the bulb neck portion facing the low voltage electrode so as to maintain said region at a relatively low and stable potential during an operation. CONSTITUTION:A thin and high resistance film 10 is arranged on a region inside a bulb neck portion 1a mainly facing a G2 electrode 4. The high resistance film 10 is obtained by evaporating the surface portion of the G2 electrode 4 made of stainless steel, iron, nickel alloy or kovar, etc. in the vacuum. This high resistance film 10 is the thickest at said region facing the G2 electrode 4 and becomes thinner as it is separated from said region in sequence. The thickness at said region is such that the color can be slightly visible to the naked eye.

Description

[Detailed Description of the Invention] The present invention is particularly applicable to low voltage electrodes such as accelerating electrodes,
The present invention relates to a cathode ray tube configured to prevent sparks from occurring between the cathode ray tube and the hook portion, and a method for manufacturing the same.

Generally, when a spark occurs inside a cathode ray tube, an excessive current flows and there is a risk of damaging the cathode and external circuit components. Therefore, the surface of the electrode is generally made smooth by polishing the electrode or by applying a forced spark treatment to the electrode by applying a high voltage equivalent to about twice that of normal operation. However, although such treatment may be a measure to prevent sparks between a high voltage electrode such as an anode and a low voltage electrode such as a focusing electrode to which one-third or less of the voltage is applied, The spark between... and the Lubnenok club p) It is difficult to make it a once-a-month plan.

According to the cathode ray tube and the manufacturing method thereof of the present invention, the surface portion of the low voltage electrode of the electron gun installed in the bulb neck is evaporated in vacuum, and the area on the inner surface of the bulb neck mainly facing the low voltage electrode is heated. A thin, high resistance film is deposited to maintain the region at a relatively low and stable potential during operation. Therefore, the generation of sparks between the low voltage electrode and the valve neck can be prevented.The present invention will now be described in more detail with reference to embodiments shown in the drawings.

In FIG. 1, inside the neck part a of a glass bulb 1 forming the cathode ray tube envelope, there are a cathode 2, an 01 electrode 3 as a control electrode, an 02 electrode 4 as an accelerating electrode, and an 03 focusing electrode. Ga 'f13. as electrode 5 and anode.
Pole 6 is enclosed. The cathode 2 is insulated and supported within the 01 electrode 3 by a field-like insulating support (not shown),
The G1 electrode 3, the G2 electrode 4, the G5 electrode 5, and the G4 electrode 6, which together with the cathode 2 constitute the electron needle, are made of rod-shaped insulating supports (
They are integrally insulated and supported by the illustrated moon tζ. Great, cathode 2, G1 electrode 3, G2 electrode 4 and G5 Dengin 6i
t, the stem part 1bq of the valve 1 is connected to a number of conductive vias that communicate with the airtight K i'j (the xa electrode 6 is in contact with the JH' city membrane 9 made of graphite via the conductive tongue 8). There is.

The conductive film 9 starts from near the area facing the G4 electrode 6 on the inner surface of the neck portion 1a of the bulb 1 and widens to +f+i within the funnel portion 1c of the bulb 1.
It is in contact with an anode button (not shown) provided on the funnel portion 1c.

. Is the above configuration the same as that of a conventional cathode ray tube?
It differs from the conventional structure in that a thin high-resistance film 1o is attached to the region facing the electrode 4. The high-resistance film 10 is made of stainless steel, iron, nickel alloy, Kovar, etc.
By evaporating the human part of the two electrodes 4 in a vacuum, it is removed. That is, after placing the electron gun in the valve notch part 1a, the stem part 1b is placed inside the valve notch part 1a.
1aV month after month.

1] Apply G2 electrode 4 to the culm for about 30 seconds to 2 minutes 8
When high-frequency heating is performed to a temperature of 00 to 900''C, a high resistance film 10 is formed by steaming and steaming.11
i1″1 indicates a high frequency heating coil.

This height (resistance film 1o) is thickest in the region VC facing the G2 electrode 4, becomes thinner as it goes away from the region, and is so thick that a slight color can be seen with the naked eye in the region.

A table considering the potential distribution on the inner surface of the bulb neck portion 1a in a conventional cathode ray tube that does not have a high resistance film 1o, as shown by curve a in FIG. There is a low voltage near the conductive pin 7.The potential distribution in the intermediate region is...
Does not change depending on the inner surface resistance/). That is, when the pulse network jτ1 mark surface in the vicinity of the conductive film 9 becomes dirty and its surface resistance decreases, the potential in the intermediate region increases. ′-! Valve neck part 1 consisting of
When the temperature of d increases due to heat generation from the cathode 2 or the deflection h+, the surface resistance decreases, so that the distribution of electric current fI'1 in the intermediate region becomes quite unstable. and,
When the inward region of the valve neck facing the 02 electrode 4 as a low voltage electrode becomes high potential, the same region and the G271L pole 4
Sparks are more likely to occur between the two.

By the way, when the high resistance film 1o is attached to the inner surface of the valve neck portion 1a as described above, this high resistance film 1o is located between the low potential region and the high potential region on the inner surface of the valve neck portion 1a and plays the role of a bleeder resistance. Moreover, since the film thickness in the region facing the G2 electrode 4 is large and the resistance Pjc value is smaller than the other regions, the potential distribution on the inner surface of the valve uneven part is as shown in the curve shown in Fig. 2. Therefore, the potential in the region facing the G2 electrode 4 is relatively low, and moreover, it is stabilized, and generation of sparks between the region and the G2 electrode 4 is prevented.

In addition, G2 electrode 4, G3 electrode 6, G4 electrode 6, etc.r(
When we conducted a strong 1tjJ test by applying a voltage of 11g, which corresponds to 125cm during normal operation, we found that the inner surface of the halb non-contact part and the 02 electrode were stronger in the case with the high-resistance film 10 than in the case without it. The average number of transfers between the three parties was approximately 1/10. Therefore, under the condition of 10 full-time employees, there is almost no risk of conflict occurring between the three parties.

Although the small (7) electrons a in Figure 1 are of the pi potential type and are of the C beam type, the present invention can also be applied to cathode ray tubes equipped with electron guns such as uniboden noyal If, 14 or double beam type. Of course, it can also be applied in the same way.The electrode that heats and evaporates is not limited to the G2 electrode;
It should be a low-voltage electrode that provides a potential less than 1/2 of the electric potential.

[Brief explanation of the drawing]

1st l゛X16:t, main part cross section 1'/1 of the cathode ray tube embodying the present invention, 21st/71r LII11 cathode ray tube and conventional cathode ray tube. FIG. 1 Nonora x bulb, 1d... neck part of the same bulb, 3 ・G1 electrode, 4... G2 electrode, 5
・・・・・・C, Electrode, 6 ・04 electrode, 9・・・・
・・Conductive film, 1° Fig. 2 n distance □

Claims (4)

[Claims] (1) It has a built-in '11Lf gun, has a 7L conductive film maintained at an anode potential at one end, and a high resistance film that is thickest in the stem and becomes thinner as it goes away from the above region at the other end. A cathode ray tube characterized by: (2) The cathode ray tube according to claim 1, wherein the low voltage electrode is an accelerating electrode. (3) Using an electrostatic gun, a conductive film kept at an anode potential at one end and a stem section at the other end are heated with high frequency on the inner surface of the valve neck, A method for manufacturing a cathode ray tube, characterized in that a surface portion of the electrode is evaporated to form a high resistance film. (4) #! that the low voltage electrode is an accelerating electrode! j
A method for manufacturing a cathode ray tube according to claim 3, wherein R.