JPS62140335A - Manufacture of color picture tube - Google Patents

Abstract

PURPOSE:To form a heat absorption film which is peeling resistant and able to suppress heat radiation reflection efficiently by evaporating an inorganic substance or a metal film both having higher melting point than aluminum at the same time of forming evaporated A1 film or following it. CONSTITUTION:A fluorescent screen 2 is formed on the inner face of a panel 1 and aluminum is evaporated on a face 2 by heating and vaporizing with heater 111, 112. Under the atmosphere of evaporation process of aluminum film, eutectic mixture of aluminum and barium, magnesium or silicon whose melting points are higher than aluminum, or eutectic mixture of aluminum and these barium, magnesium or silicon plus aluminum are heated and vaporize by heating heater 12, and evaporized on predetermined position. Hence, the thermal radiation is adsorbed and doming phenomenon is suppressed.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a color picture tube, and particularly to a method for forming a heat-absorbing film on a phosphor screen that can reduce doming of a shadow mask. The present invention relates to a method of manufacturing a color picture tube.

[Technical background of the invention and its problems]

In recent years, color picture tubes have been classified into Franc 1 to square tubes (F
There is a tendency for devices with near-flat screens called s-tubes, and shadow mask type devices with large deflection angles, such as 110° deflection tubes, to become popular. Is this type of color picture tube similar to a normal color picture tube because it needs to provide a good image?

More than that, it is desirable for the electron beam to land accurately on the phosphor stripes or dots.

Next, a simplified configuration of the panel section of a commonly used color picture tube will be explained with reference to FIG.

That is, a double layer consisting of the fluorescent screen (2) and the aluminum vapor deposited film (3) is formed on the inner surface of the panel (2).

This vapor-deposited film (2) increases the brightness of the phosphor screen (2) and prevents ion burnout of the phosphor screen (2), and is well known as a metal back electrode. Shadow masks 0) are provided on this vapor deposited film (3) at regular intervals.

The operation of the color picture tube having such a configuration is as follows. First, when an electron beam is emitted from the electron gun, this electron beam passes through the electron beam passage hole of the shadow mask 0) and hits the aluminum 11 vapor deposited film (3) and the phosphor screen (2) to reach a predetermined position. Supply images.

In this case, part of the electron beam passes through the electron beam passage hole of the shadow mask G), but the other part impinges on the shadow mask (G) and heats it.

Therefore, the shadow mask 0) radiates heat and emits thermal radiation, and due to this radiation, it receives again the thermal radiation reflected from the aluminum vapor deposited film (3) and is further heated. As a result, conventional color picture tubes have the following problems. In other words, since the shadow mask (A) is heated, especially when a white part is received locally, the shadow mask expands and deforms, causing the phosphor stripes and dots on the phosphor screen (2) to change. On the other hand, a deviation occurs in the landing of the electron beam. This is generally regarded as a problem as a doming phenomenon, but as a product, it causes defects related to the color purity of the screen, such as partial loss of white balance and increased stabilization time until white adjustment. This is more noticeable in Fs tubes and wide-angle deflection tubes.

In order to solve this problem, in conventional color picture tubes, a graphite coating film (■) is formed on the surface of the aluminum vapor-deposited film (■) of the phosphor screen (■), as shown in FIG.
The radiant heat from the shadow mask O is absorbed by the heat absorption effect of the shadow mask O) (U.S. Pat. No. 370,340).
No. 1). However, graphite coating film 0 must be applied by dissolving graphite in a solvent such as water and then spraying, and this coating process must be performed separately from the aluminum vapor deposition film ■ on the phosphor screen ■. This makes the process cumbersome and makes continuous work impossible. In addition, the graphite in the graphite coating film (1) tends to form large particles, which peel off due to friction or vibration, resulting in problems such as defects on the phosphor screen of color picture tubes and a decline in withstand voltage quality.

Furthermore, as another method, there is a method in which the degree of vacuum is lowered at the final stage of the vapor deposition process of the aluminum vapor deposited film to blacken the outer surface of the aluminum vapor deposited film to reduce the reflectance. However, according to this method, two-stage evaporation at a high vacuum level and a low vacuum level is required, and even if the vacuum level is continuously lowered, it becomes difficult to control the leak start timing and leak amount. Moreover, it is not possible to obtain a deposited film of constant quality, and furthermore, there are various problems such as oxidation of the deposition heater due to its contact with air and increased wear and tear.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and provides a method for manufacturing a color picture tube that can effectively suppress the reflection of thermal radiation and form a heat-absorbing film that is difficult to peel off. is intended to provide.

[Summary of the invention]

The present invention is characterized by providing a step of forming a vapor deposited film of an inorganic substance or metal having a melting point higher than that of aluminum, either simultaneously with or subsequent to the step of forming an aluminum vapor deposition film on the phosphor screen formed on the inner surface of the panel.

[Embodiments of the invention]

Next, an example of the method for manufacturing a color picture tube according to the present invention = 4- An example will be explained with reference to FIGS. 1 to 3.

That is, on the inner surface of the panel (1), a phosphor screen (2) consisting of a striped or dot-shaped phosphor layer that emits light in three colors, red, green, and blue, is formed by a conventional method. Next, the panel (■) on which the fluorescent screen (■) has been formed is placed on a vacuum device (not shown), which is equipped with a heater (not shown) that heats the aluminum.
11, ) and (112) and a heater (12) for heating the magnesium. A heater for heating this magnesium is placed corresponding to a position where a heat-absorbing film is desired to be formed.

Next, the inside of the panel including the vicinity of the tops of the heaters (11□), (11□), and (12) is brought into a vacuum state of 10-4 to 10-s Torr.

Next, rod-shaped aluminum (not shown) is heated and evaporated using heaters (111) and (11□) to form an aluminum vapor deposition film (13) as shown in FIG.

Next, while maintaining the vacuum state, rod-shaped magnesium (not shown) is heated and evaporated by a heater (12) to form a magnesium vapor deposited film (15) on the aluminum vapor deposited film (13) as shown in FIG. The position of the part on which the magnesium vapor deposited film (15) is vapor-deposited differs depending on the color picture tube, so it is important to effectively vapor-deposit it at a predetermined position. This magnesium vapor deposited film (15)
According to experiments, the color is close to black, but this is thought to be due to adsorption of gas and moisture in the tube, or a type of oxidation phenomenon caused by heating during vapor deposition.

As a result, a magnesium vapor deposited film (15) with a color close to black is formed at a predetermined position of the aluminum 11 vapor deposited film (13), so that the thermal radiation emitted from the shadow mask is absorbed and the doming phenomenon is suppressed. Ru.

According to experiments, in addition to magnesium, there are other substances such as gallium, silicon, etc.
A eutectic mixture of silicon and aluminum may also be used.

For example, in the case of a silicon-aluminum alloy body, when silicon was mixed with aluminum in an amount of 0.5 to 15%, quality equivalent to that of graphite spray could be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the aluminum vapor deposition film and the heat-absorbing film can be formed simultaneously or sequentially using the same equipment, so the process is simple and it is possible to obtain a good heat-absorbing layer. can.

[Brief explanation of drawings]

1 to 3 are diagrams showing one embodiment of the present invention,
Fig. 1 is a simplified explanatory diagram showing the relationship between the main parts of the color picture tube and the vapor deposition heater, Fig. 2 is an explanatory diagram showing the state in which an aluminum vapor deposited film is formed, and Fig. 3 is a magnesium vapor deposited film on the aluminum vapor deposited film. FIG. 4 is a sectional view of a main part of a general color picture tube, and FIG. 5 is an explanatory diagram showing a state in which a conventional graphite coating film is formed.

Claims (2)

[Claims] (1) A process of forming an aluminum vapor deposited film on the phosphor screen formed on the inner surface of the panel, and simultaneously or subsequently, a step of forming an inorganic or metal vapor deposited film having a higher melting point than aluminum is provided. A method of manufacturing a color picture tube. (2) A color picture tube according to claim 1, wherein the inorganic substance or metal with a high melting point is barium, magnesium, silicon, or a eutectic mixture of barium, magnesium, silicon, aluminum, and aluminum. manufacturing method.