JPS6222357A - Shadow mask - Google Patents

Abstract

PURPOSE:To alleviate the local temperature increase of a shadow mask so as to reduce its thermal deformation by forming sintered layers fused to areas surrounding the penetrating holes of the shadow mask over its inner surface with spaces allowed between the inner surface and the sintered layers. CONSTITUTION:First layers 14 are formed by applying a vehicle to the inner surface of a shadow mask 10. Second layers 15 are formed by applying a liquid suspension prepared by adding a proper amount of a vehicle to a low-melting- point pewter glass powder to the inner surface before drying the applied suspension. Next, the thus formed layers 14 and 15 are sintered by heating them at 400-500 deg.C for 20-30min to form sintered layers 16. These sintered layers 16 receive electron beams striking against the shadow mask 10 and prevent the beams from directly striking against the shadow mask 10. Consequently, the temperature increase of the shadow mask 10 is alleviated even when the temperature of the sintered layers 16 increases, thereby preventing any local doming.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shadow mask that reduces thermal deformation during operation.

[Conventional technology]

First, the structure of the color cathode ray tube (1) will be briefly explained with reference to FIG. A color cathode ray tube (1) usually has a spring /L' (21) having a spherical inner surface, a nine fluorescent surface (3) provided on this inner surface, and a funnel N(21) having an approximately conical shape connected to the spring lv+21. 4), a pipe-shaped neck part (5) connected to this, and a plurality (usually 3) of electron guns (usually 3) arranged in a row inside the neck part (5).
) and a V-yado mask +1 (11), which are arranged to face each other at a suitable distance inside the fluorescent surface (3). 1) Explanation and diagrams of the mechanism held within are omitted.

As is well known, when a color cathode ray tube with a shadow mask is operated, a portion of the electron beam passes through a hole formed in the 'V Yadow mask and impinges on the fluorescent surface.
Along with making it emit light.

Most of the residue hits the V-Yado mask, raising its temperature ◇As a result, the thin metal plate forming the shadow mask thermally expands, causing heat that impairs the operating characteristics of the color cathode ray tube. One type of thermal deformation that is difficult to counteract is a phenomenon called local doming. This phenomenon is caused by the fact that when a stationary or nearly static screen is projected where a relatively small area, for example a circle with a diameter of 20 mm to 100 mm, is particularly bright, the temperature of this corresponding area of the shadow mask increases locally. Even though the heated portion undergoes thermal expansion, the surrounding portion does not undergo thermal expansion, so it bulges toward the spring μ.

Various proposals have been made to improve this doming phenomenon, one of which is a double mask method.

As shown in Figure 3, the double mask method consists of placing a second shadow mask at a certain distance on the electron gun side of the head of the shadow mask, and removing the extra electron beam that hits the mask α■. The idea is to shield this as much as possible with the second shadow mask@. The through hole αJ formed in the second shadow mask (2) through which the electron beam passes is sufficiently large, so that even if a local doming phenomenon occurs due to the impact of the electron beam, the first shadow mask (1) The structure is such that no electron beam is transmitted through the through hole.

[Problem that the invention seeks to solve]

However, the current situation is that this double mask/screen system has not been realized. The reason for this is that the shadow mask αα and the second shadow mask ■ are manufactured separately and placed at a predetermined distance apart, which makes it difficult to achieve the dimensional accuracy required for each component and to ensure assembly accuracy. This is because it is difficult to realize in practice.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a shadow mask that is free from local doming and has high dimensional accuracy.

[Means for solving problems]

In this invention, each hole is fused to the inner peripheral edge of each hole formed in the shadow mask, and is opposed to the inner surface between each hole of the shadow mask with a gap maintained between the holes. It is equipped with a sintered body layer formed as follows.

[Effect]

The sintered body layer covers the inner surface of the shadow mask except for the portions of the through holes, and receives the electron beams that strike the V-yado mask, thereby preventing them from directly striking the shadow mask. are doing. The wide surface area of this sintered body layer faces the inner surface of the shadow mask with a gap maintained, so even if the temperature of the sintered body layer locally rises due to the impact of the electron beam,
The temperature rise in that part of the mask is alleviated. Therefore, even under conditions where local doming occurs, local doming does not occur, and the same effect as the conventional double mask type V-yado mask can be obtained.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1(a) to 1(0).

First, the inner surface of the shadow mask αα heated to around 200°C is
．． 5%, nitrose μ-lose 1.5%) and apply about 10%
A first coating layer (141) having a thickness of .mu.m is deposited as shown in FIG. 1(a).

In this first coating step, a shadow mask (1a1
The purpose of heating is to accelerate the drying of the coating layer α and to make the thickness of the coating layer α uniform. In this case, the thickness is 10
If it is thicker than μm, there is a possibility of blocking the through hole 0 of the shadow mask (101), and if it is thinner than this, there is a possibility that cuts will occur in the coating layer αa.The area where the coating layer (14) is formed is as follows: The surface area t is approximately the same as the area where the through hole 1 is formed.The coating method may be a spray method or other suitable method.

After drying the first coating layer, a second coating layer is formed as shown in FIG. 1(b).

The second coating layer is made of low melting point solder glass powder, for example.
A suitable amount of dotori μ is added and mixed to form a suspension, which is applied to a slightly wider area than the area where the first coating # (14) was formed, to a thickness of 20 to 30 μm, Dry and form.

In this second coating step, the coating thickness is 20 to 30 μm.
mK is because the suspension applied to this thickness on the first coating layer (14) forms through holes (11) due to surface tension.
This is because the sintered body layer formed after the post-working firing process will have an appropriate shape and strength.

Also, the reason why the second coating layer (5) is made slightly wider than the area of the first coating layer α3 is because of the through-hole αυ of the V-yado mask α■.
This is to increase the strength of the sintered body layer by fusion bonding the sintered body layer to the shadow mask α■ also at the peripheral edge of the area forming the area.

Next, apply the first and second coating layers (14), (shadow masks with I51 coated thereon (1al, 400 to 50%
A baking process of heating at 0°C for several tens of minutes was performed, and the resultant material was shown in Figure 1(e).
A sintered body layer αe shown in FIG.

In this firing step, the nitro-7 μ-loose forming the first coating layer (141) is thermally decomposed to form voids αη. As it thermally decomposes, the low melting point solder glass powder fuses with each other to form a sintered layer, forming a through hole.
The peripheral edge portion (16a) and outer peripheral edge portion (16b) of the mask are fused to the shadow mask αω and firmly attached to the mask α0.

The sintered body layer αe formed in this way blocks the electron beam that impinges on the shadow mask αC and blocks the electron beam from directly impinging on the shadow mask (101-). Under conditions where doming occurs, even if the temperature of the relevant portion of the sintered body layer αe increases,
The temperature rise in the relevant part of the V Yadou mask αα is alleviated,
No local doming occurs.

In this way, the sintered body layer α mark having the void αη has the same effect as the second mask of the conventional double mask method.

In the above example, an example was shown in which the first coating layer was formed using vehicle μ and the second coating layer was formed using a vehicle suspension of low melting point solder glass powder. The invention is not limited to these examples or combinations.

〔Effect of the invention〕

In this invention, the resin is fused to the inner surface of the shadow mask at the peripheral edge of each through hole, and the portion between the through holes is formed so as to face and cover the inner surface of the shadow mask while maintaining a gap. A Nyadou mask equipped with a sintered body layer, the electron beam impinges on the sintered body layer to increase its temperature, and V
Since the Yado mask only transmits thermal energy μ by heat conduction through the sintered body layer and heat radiation through the voids, there is no local temperature rise even under conditions that cause local doming. is relaxed, and a shadow mask with less thermal deformation can be obtained.

[Brief explanation of the drawing]

Figures 1 (a) to (0) are partially enlarged cross-sectional views for explaining the manufacturing process of an embodiment of the present invention, and Figure 1 (c) is a finished product of the embodiment of the present invention. FIG. 2 is a partially cutaway perspective view showing the configuration of a shadow mask cathode ray tube, and FIG. 3 is a partially cutaway side view of a color cathode ray tube having a conventional second V-yado mask. . (1)...color cathode ray tube, α■...shadow mask, (IB...through hole, α small...first coating layer, (to)...second coating layer, ...Sintered body layer, αη...
void. In the drawings, the same reference numerals indicate the same parts or the same parts. Figure 1 10 = Shadow mask 17: Gap Figure 2 Figure 3 Procedures and amendments (voluntary)

Claims (2)

[Claims] (1) It is fused to the inner peripheral edge of each through-hole formed in the shadow mask, and is formed so as to face the inner surface between the through-holes of the shadow mask while maintaining a gap. A shadow mask equipped with a cohesive layer. (2) The shadow mask according to claim 1, wherein the sintered body layer is made by sintering low melting point solder glass powder.