JPH0246621A - Manufacture of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To improve the picture quality without reducing the heat radiation rate by applying no baking process to a heat absorption substance membrane formed at the inner surface of a photoreflection type metallic membrane. CONSTITUTION:A phosphor membrane 5, an intermediate membrane 8, and a photoreflection type metallic membrane 9 are formed at the inner surface of a face plate 2 in this order, and a baking process is applied immediately after the formation of them. Evaporation sources 17 are heated by applying a current, aluminum material 18 included in coils is molten and evaporated, and a heat absorption substance membrane 100 is formed at the inner surface of the photoreflection type metallic membrane 9, that is, the inner surface of an electron gun 11 side. In this case, no baking process is applied to the heat absorption substance membrane formed at the inner surface of the photoreflection type metallic membrane. As a result, the heat radiation rate is not reduced remarkably, the radiant heat of a shadow mask is absorbed sufficiently to reduce its thermal deformation, and the picture quality can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to a shadow mask that is formed on the inner surface of a face plate in order to absorb the radiant heat of a shadow mask built into a color cathode ray tube and suppress its thermal expansion. The present invention relates to a method of manufacturing a color cathode ray tube having a thin film of heat absorbing material.

[Prior Art] FIG. 2 is a sectional view showing a conventional color cathode ray tube of this type.

(1) is a vacuum envelope made of glass, and is formed by a face plate (2), a funnel part (3), and a neck part (4) containing an electron gun (11). (
5) is a fluorescent film coated on the inner surface of the F face plate (2), and this fluorescent film (5) consists of three-color mosaic-shaped light bodies of red, green, and blue spaced apart at a predetermined pitch. It is formed by arranging the

(8) is a smooth and thin intermediate film formed on the inner surface of the fluorescent film (5) by a filming process, and is made of an organic material such as nitrocellulose or polymethacrylate, which is easily thermally decomposed. This intermediate film (8) is for flattening the inner surface of the fluorescent film (5) which has irregularities, and is removed by thermal decomposition during the baking process in the subsequent process. (8)
Only a light reflective metal thin film (9) such as aluminum (also referred to as a metal back thin film) vacuum-deposited on the inner surface of the fluorescent film (5) remains on the inner surface of the fluorescent film (5). Therefore, this FIG. 2 shows that the intermediate film (
8) is present.

(+01 is a heat-absorbing thin film made of aluminum or the like formed by vacuum deposition on the inner surface of the light-reflective metal thin film (9), and this heat-absorbing thin film (lO) is placed on the inner surface of the light-reflective metal thin film (9) facing each other with a predetermined gap. This is provided to absorb the radiant heat of the shadow mask (5) and suppress the thermal expansion of the shadow mask (6).

(6) is a shadow mask, which is a thin film of L heat-absorbing material (1
0), and is attached to a frame-shaped mounting frame (7) fixed to the inner circumferential surface of the face plate (2).

In addition, in the next step after vacuum-depositing the heat-absorbing substance thin film on the inner surface of the light-reflective metal thin film (9) as described above, the fluorescent film (
In order to thermally decompose and eliminate the L mud interlayer film (8) formed between the light-reflecting metal thin film (9) and the light-reflecting metal thin film (9), a baking treatment is performed together with the heat-absorbing material thin film (10). After this, the opening of the face plate (2) and the opening of the funnel part (3) of the vacuum envelope (1) are sealed with frit glass (12) to complete the assembly process of the color cathode ray tube. .

Since the conventional color cathode ray tube is constructed as described above, the electron beam emitted from the electron gun (11) passes through the hole in the shadow mask (6) and hits each of the fluorescent films (5). The fluorescent point is irradiated to cause it to emit light, but at this time, the transmittance of the L electron beam passing through the shadow mask (6) is extremely low at 15-30%, and the remaining 70-85%
The electron beam collides with the shadow mask (6), and the collision energy causes this shadow mask (6) to become 75
In order to raise the temperature to 80°C to 80°C, this shadow mask (5) is thermally deformed, and the relationship between each electron beam transmission hole (7) of the shadow mask (6) and the phosphor mosaic of the fluorescent film (5) is The relationship changes and the color purity decreases, such as color shift on the screen (
−・Generally called the doming phenomenon).

As a means to deal with this phenomenon, as described in 1., a shadow mask (
A heat-absorbing thin film (10) made of aluminum or the like is formed to absorb the radiant heat of 6).

[Problems to be Solved by the Invention] As described above, the heat-absorbing substance thin film (lO) made of aluminum or the like in the conventional color cathode ray tube does not adhere to the inner surface of the light-reflecting metal thin film (9) as described in 1-. Not only is the binder contained in the fluorescent film (5) and the intermediate film (8) formed between the fluorescent film (5) and the light-reflective metal thin film (9) At the same time as the baking treatment to thermally decompose and remove the heat-absorbing substance, the heat-absorbing thin film (10) turns into aluminum oxide and becomes transparent, and the thermal emissivity decreases significantly. There is a problem in that the radiant heat of the shadow mask (6) cannot be sufficiently absorbed to prevent thermal deformation of the shadow mask.

This invention has been made to solve the above-mentioned problems, and aims to reduce the thermal deformation of the shadow mask by preventing the decrease in the thermal emissivity of the heat-absorbing material thin film, thereby achieving improvement in image quality. An object of the present invention is to provide a method for producing a thin film of a heat-absorbing substance.

[Means for Solving the Problems] A method for manufacturing a color cathode ray tube according to the present invention includes a fluorescent film sequentially formed on the inner surface of a face plate of a vacuum envelope;
After baking the intermediate film and the light-reflecting metal thin film, a heat-absorbing substance thin film was vacuum-deposited on the inner surface of the light-reflecting metal thin film.

[Function] According to the present invention, since the heat-absorbing thin film formed on the inner surface of the light-reflecting metal thin film is not subjected to baking treatment, the aluminum of the heat-absorbing thin film is oxidized and becomes transparent. There is no significant decrease in thermal emissivity.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a sectional view showing a manufacturing apparatus for explaining a method of manufacturing a color cathode ray tube according to an embodiment of the present invention. The method for forming the reflective metal thin film (9) is the same as the conventional method shown in FIG. 3, so the explanation thereof will be omitted.

However, the fluorescent film (5) and the intermediate film (8) according to the present invention
The difference from the conventional method is that the light-reflective metal thin film (9) is sequentially formed on the inner surface of the face plate (2) as shown in FIG. 2, and then immediately subjected to baking treatment.

In Fig. 1, (13) is a vapor deposition container, and the flange part (14) on the opening side of this container has the opening side edge of the face plate (2) which has been subjected to baking treatment as shown in Fig. 2 above. Polymerization is carried out in an airtight manner via a backing (15), and inside this vapor deposition container (13), when a heat absorbing substance thin film (+00+) is vacuum vapor deposited on the inner surface of the light reflective metal thin film (9), , the suction pipe (16) is evacuated to 0.
It is maintained at a vacuum of 1 to 5 Torr. (17) is a plurality of coiled evaporation sources made of tungsten wire, etc., which are disposed in the vapor deposition container (13) at a distance of about 200 mm from the light-reflective metal thin film (9). The evaporation source (!7) is heated to approximately 1500"C by supplying electricity to it, melting and evaporating the aluminum material (18) housed in the coil, and causing the inner surface of the light-reflective metal thin film (9), i.e. A heat absorbing material thin film T100I is formed on the inner surface on the electron gun (11) side.

As mentioned above, after finally vacuum-depositing a heat-absorbing material thin film (+001) on the inner surface of the face plate (2),
Opening of face plate (2) and vacuum envelope (1)
The opening of the funnel part (3) and the frit glass (1
By welding in step 2), the assembly of the color cathode ray tube is completed.

In addition, although the above-mentioned example described the case where aluminum was used as the material for the heat-absorbing substance thin film +100) formed on the inner surface of the light-reflecting metal thin film (9), the same result could be obtained even if graphite or carbon was used. Effects can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the heat-absorbing thin film formed on the inner surface of the light-reflecting metal thin film is not subjected to baking treatment, the aluminum of the heat-absorbing thin film is It does not oxidize and become transparent, causing a significant drop in thermal emissivity, and has the effect of sufficiently absorbing the radiant heat of the shadow mask, reducing its thermal deformation, and improving image quality. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a manufacturing apparatus for explaining a method of manufacturing a color cathode ray tube according to an embodiment of the present invention, FIG. 2 is a sectional view of a face plate, and FIG. FIG. (+)...Vacuum envelope, (2)...Face plate. (5)... Fluorescent film, (8)... Intermediate film, (9) -
...Light-reflective metal thin film, (10)...Heat-absorbing material thin film. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1

Claims (1)

[Claims] (1) Forming a fluorescent film on the inner surface of the face plate of the vacuum envelope, forming an intermediate film on the inner surface of this fluorescent film, and vacuum-depositing a light-reflecting metal thin film on the inner surface of this intermediate film. a step of baking the fluorescent film, the intermediate film, and the light-reflecting metal thin film; and a step of vacuum-depositing a heat-absorbing substance thin film on the inner surface of the light-reflecting metal thin film subjected to the baking treatment. A method for manufacturing a color cathode ray tube, characterized in that: