JPH0471144A - Shadow mask for cathode-ray tube - Google Patents

Abstract

PURPOSE:To remarkably enhance a thermal deformation restricting effect of a shadow mask by laminating a coating film made of a black inorganic pigment exclusive of carbon and graphite on a coat including mainly a specific mixture formed on a shadow mask material. CONSTITUTION:Aheat radiating film 3 made of a black inorganic pigment exclusive of carbon and graphite is laminated on an anti-doming film 2 including mainly a mixture of Bi2O3, Bi12SiO20, Bi12GeO20, Bi12TiO20, Bi2O3 and Bi12SiO20, a mixture of Bi2O3 and Bi12GeO20, or a mixture of Bi2O3 and Bi12TiO20 formed on a shadow mask material 1, thus obtaining a shadow mask for a cathode-ray tube. The anti-doming film 2 has the function of reflecting an electron beam with an effect of 30%. The heat radiating film 3 is adapted to prevent an increase in temperature of the shadow mask due to heat radiation, thus enhancing the effect by about 20%. Therefore, an anti-doming effect becomes 50% (30%+20%), namely, enhanced by about 70% compared with conventional shadow masks.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for forming a thermal deformation suppressing film that is useful for color cathode ray tubes in which the kinetic energy of electron beams is increased in order to improve the brightness of the cathode ray tube. Regarding shadow masks.

[Prior Art/Problems to be Solved by the Invention] Conventionally, an anti-doming film (thermal deformation suppressing film) formed on a shadow mask material of a cathode ray tube was disclosed in Japanese Patent Publication No. 80-14459 by the present inventors; JP-A-82-281240, JP-A-62-281241, JP-A-62-
283525, JP 62-295329, JP 63-18085, JP 63-213
As disclosed in Publication No. 238 etc., Bi2O3
A step of adding a predetermined amount of water glass and water to a powder or a mixed powder of Bi2O3 and Bi2SiO20 and mixing it to a predetermined viscosity, a step of spraying this mixed liquid onto a shadow mask material and letting it air dry; After positioning the shadow mask on the face panel of the cathode ray tube,
It is formed by a step of baking at 50° C. for 30 minutes (such baking means is generally called pair baking). FIG. 2 is an enlarged cross-sectional view of a portion of the shadow mask having the anti-doming film (2) formed in this manner.

In addition, instead of the Bi12SIO20 mentioned above, the old I2Ge
Even if O20 or Bil2TiOm powder is used, the same performance can be obtained.

However, the upper limit of the anti-doming effect (thermal deformation suppressing effect) due to the anti-doming film (2) mainly composed of a mixture of Bi2O3 and Bia SIO20 on such a conventional shadow mask material (1) is about 30%. It is.

Therefore, as a method to improve the anti-doming effect, a method of forming a thermal radiation layer on the coating is being considered. For example, when using carbon, partially graphitized graphite, graphite, etc. These will burn and disappear during the subsequent firing in the air, so
It is very difficult to provide a thermal radiation layer using these materials. Additionally, a method of providing a thermal radiation layer using tungsten powder is being considered, but this method progresses oxidation of tungsten and generates WOz and wO3, making it difficult to provide a high-performance thermal radiation layer. There is a problem.

The present invention was made to improve the upper limit (30%) of the anti-doming effect of conventional anti-doming films, and can achieve an excellent anti-doming effect of 50% or more that can be manufactured by simple and inexpensive means. Aim to scale the shadow mask with.

[Means for Solving the Problems] The present invention provides Bi2O3, Bi12 on a shadow mask material.
SiO211s Bi+z GeO20s Bi+z
Ti020% A coating film of a black inorganic pigment excluding carbon and graphite was further provided on a coating mainly composed of a mixture of Bi2O3 and Bi+z SiOzo, a mixture of Bi2O3 and old +2 GeO211, or a mixture of Bi2O3 and Bil2TiOn. The present invention relates to a shadow mask for a cathode ray tube.

[Operation/Example] As shown in FIG. 1, the shadow mask of the present invention includes Bi2O3, Bi1281020, etc. on the shadow mask material (1) in order to reflect the electron beam and suppress thermal deformation.
, Bi12GeO20, Bi12T1020, B
Mixture of i20x and Bi12S10211, Bi2O
3 and Bi12GeO20 or a mixture of Bi2O3 and Bi+2T1020 as a main component and containing a binder (hereinafter also referred to as an anti-doming film)
[2] is provided.

As the shadow mask material, iron material (C: 0.10%
Below, Mn: 0.25-0.45%, P: 0.03
5% or less, S: 0.040% or less, 81:
0.10% or less, lV: 0.10% or less, Fe: balance)
Examples include things such as:

Examples of the anti-doming film include the anti-doming film disclosed in Japanese Patent Application Laid-Open No. 82-281241.

The proportion of the main component in the antidoming film is 9
It is preferably 4 to 96% (by weight, hereinafter the same).

The anti-doming film contains a binder such as sodium water glass or potassium water glass.

There is no particular limit to the thickness of the anti-doming film, but 2
A value of 0-10 or less, more preferably 5-10, is preferable from the viewpoint of reducing the amount of gas released into the color cathode ray tube during operation.

The shadow mask of the present invention includes a coating film of a black inorganic pigment excluding carbon and graphite on the anti-doming film (a) as shown in FIG. (hereinafter also referred to as a thermal radiation film) (3) is provided.

The thermal radiation film is obtained by bonding the black inorganic pigment with a binder.

The black inorganic pigment contained in the thermal radiation film is other than carbon and graphite, and such black inorganic pigments do not burn and disappear like carbon and graphite even when fired in air, and tungsten The three components of MnO2, Pe5Oa, and CuO were thoroughly ground and mixed because they do not undergo oxidation like powders, are chemically unchanged, and are stable substances that can maintain high thermal emissivity. Also, N10 instead of CuO
It is preferable to use 5CrO or the like.

The ratio of each component in the black inorganic pigment consisting of MnO2, pe30a and CuO is 30 to 70% for Mn02 and 15% for Fe50+ in order to make the thermal emissivity 0.9 or more.
-85%, CuO is preferably in the range of 15-35%. If the proportion of MnO2 is less than 30%, the pulverizability decreases and handling tends to become difficult. If the proportion exceeds 70%, the thermal emissivity tends to decrease. The proportion of Fe3O4 is 15%
If it is less than 35%, the thermal emissivity tends to be low, and if it exceeds 35%, the oxidation resistance will be poor and the color fading tendency will increase.

If the proportion of CuO is less than 15%, the thermal conductivity decreases, and 35
%, the thermal emissivity tends to decrease.

Among the black inorganic pigments, for example, 47% MnO, F
The material made of e30425% and Cu028% has a thermal emissivity of 0.93.

The proportion of the black inorganic pigment in the thermal radiation film is 70 to 70.
95% is preferred, and 85-95% is more preferred.

When the ratio is less than 70%, the thermal emissivity decreases, and when it exceeds 95%, the adhesiveness decreases.

The thermal radiation film contains a binder such as sodium water glass or a mixture of sodium water glass and potassium water glass.

The thermal radiation film used in the present invention has almost no electron beam reflection ability and is sufficiently effective even if it is thin, so it is preferably as thin as possible, and the film thickness is 0.5 to 5.
It is preferable that it be within the range of 0.5 to 2 J. If the film thickness is less than 0.5 J1, the ability tends to decrease, and if it exceeds 5 J, the electron beam reflection ability decreases, and the temperature rise tends to increase.

Next, a method for manufacturing a shadow mask according to the present invention will be explained.

First, Bi2O3, Bi+2SiO20, Bil2Ge
02(, Bi12TiO20SB*203 and Bi12
Mixture with Si020, Bi2O3 and Bil2Ge02
A small amount of sodium-based water glass or a mixture of sodium-based water glass and potassium-based water glass, and an appropriate amount of water are added to the mixture with 11 or the mixture of Bi2O3 and old 12Ti020 to form a spray liquid for forming an anti-doming film. Prepare.

On the other hand, add 60 cc of water to, for example, 30 g of black inorganic pigment, pulverize it to an average particle size of 1 or less by a suitable means such as a ball mill, add 22 cc (20% SiO2) of sodium water glass or sodium water glass and potassium A black inorganic pigment spray solution is prepared by mixing the mixture with water glass.

Next, a spray liquid for forming an anti-doming film is applied to the shadow mask material by a spray method so that the film thickness after drying is 20 mm.
-Apply as follows. (For shadow masks that do not have a conventional heat radiating film, after drying it,
Manufactured by firing in air at 450°C for 30 minutes. ) Immediately or after some natural drying, a black inorganic pigment spray liquid is applied by a spray method so that the film thickness after drying is 0.5 to 5 mm. Then dry,
For example, by firing in the usual firing process of 20 to 30 minutes at 400 to 450° C. in air, water evaporates from the coating and a strong coating is formed due to the bonding action of water glass.

As mentioned above, the anti-doming film is responsible for the function of reflecting the electron beam when the shadow mask is irradiated with the electron beam (30% anti-doming effect), but the thermal radiation film is responsible for increasing the temperature of the shadow mask due to thermal radiation. The anti-doming effect is improved by about 20%. Therefore, the anti-doming effect of the shadow mask of the present invention is 50% (30% + 20%), which improves the anti-doming effect of a normal shadow mask with an anti-doming film by about 70%, and is compared with the -stage and invar masks. The performance is close to that of .

Next, the present invention will be explained based on Examples, but the present invention is not limited to these Examples.

Example 1 42 parts of water was added to 42 parts of Bi2O3 powder (parts by weight, the same applies hereinafter), and the mixture was ground to an average particle size of 1 item or less using a ball mill for 3 days. To this, 16 parts of potassium water glass and sodium water glass were added. A spray solution for forming an anti-doming film was prepared by mixing.

On the other hand, the main components are MnO2, Pe3o4 and CuO(7
) Add 53 parts of water to 28 parts of the material, and ball mill for 1 day to obtain an average particle size of 0.5. ca or less, and 19 parts of potassium water glass and sodium water glass were mixed thereto to prepare a black inorganic pigment spray liquid.

The above-mentioned spray liquid for forming an anti-doming film is applied to a shadow mask material with a thickness of 0.2 cm made of iron material by a spray method, and after drying at 80°C for about 15 minutes, the above-mentioned black inorganic pigment spray liquid is applied on top of it. was applied by a spray method and baked in air at 450°C for 30 minutes. The thickness of the anti-doming film thus formed was 1.5 mm, and the thickness of the thermal radiation film was 0.8 mm.

A CRT was manufactured using the obtained shadow mask of the present invention. When the obtained CRT is operated, the shadow mask is heated (approximately 40 degrees Celsius) by the impact of the electron beam.
As a result, the shadow mask is deformed, and the impact position of the electron beam passing through the shadow mask on the phosphor screen is moved. This amount of movement was actually measured using a microscope. This corresponds to the anti-doming effect of the shadow mask. The results are shown in FIG. 3 as (A).

Figure 3 is a graph showing the anti-doming effect of the shadow mask, where the vertical axis is the anti-doming effect and the horizontal axis is C.
The elapsed time of the RT operation is shown.

Comparative Examples 1 to 2 Anti-doming effects were measured for a shadow mask having only an anti-doming film (Comparative Example 1) and a shadow mask material only (Comparative Example 2) obtained in the same manner as in Example 1 except that no thermal radiation film was formed. did. The results are shown in FIG. 3 as (B) and (C), respectively.

[Effects of the Invention] As described above, the shadow mask of the present invention has a thin thermal radiation layer made of a black inorganic pigment excluding carbon and graphite, which can be provided easily and inexpensively, on the anti-doming film. The effect of suppressing thermal deformation of the shadow mask is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a portion of a shadow mask of the present invention, FIG. 2 is an enlarged sectional view of a portion of a conventional shadow mask, and FIG. 3 is a graph showing the anti-doming effect of the shadow mask. (Numbers in drawings) (1): Shadow mask material [2], anti-doming film C3): Thermal radiation film

Claims (1)

[Claims] (1) Bi_2O_3, Bi_1 on the shadow mask material
_2SiO_2_0, Bi_1_2GeO_2_0, B
i_1_2TiO_2_0, Bi_2O_3 and Bi_1
Mixture with _2SiO_2_0, Bi_2O_3 and Bi
Mixture with _1_2GeO_2_0 or Bi_2O_
1. A shadow mask for a cathode ray tube, characterized in that a coating film of a black inorganic pigment excluding carbon and graphite is further provided on a coating film mainly composed of a mixture of No. 3 and Bi_1_2TiO_2_0.