JPS61208724A - Manufacture of color picture tube - Google Patents

Abstract

PURPOSE:To reduce the quantity of wrong landing, by performing baking so that a glass layer with a smaller coefficient of expansion than the material of a shadow mask is provided on the electron-gun-side main surface of the shadow mask, and by combining a panel with a mask to provide a fluorescent surface. CONSTITUTION:A shadow mask material having numerous through holes 51 along a main surface 50 is press-formed so as to extend along the form of the inside surface of the panel of a color picture tube. At that time, the shadow mask material is provided with a peripheral flange 8 for securing the material to a frame 7. Baking is then performed so that a glass layer 52 made of a lead borate glass or the like and having a smaller coefficient of expansion than the mask material is provided on the electron-gun-side main surface of the material. A panel and a mask are thereafter combined with each other to provide a fluorescent surface on the inside of the panel. According to this constitution, even if the mask is deformed due to the baking, the wrong landing of an electron beam on the panel is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a shadow mask type color picture tube, and particularly to a method for forming a shadow mask.

rfi IIIFI M service? 8 & t, concave 1 m j": '1 Generally, as shown in Fig. 1, a shadow mask type color picture tube has an envelope typically formed of an insulator, and a substantially rectangular panel (1). It consists of a funnel-shaped funnel (2) and a neck (3).The inner surface of the panel (1) is provided with, for example, a striped phosphor screen (4) that emits red, green, and blue light, respectively. ,
On the other hand, the net (3) is equipped with a so-called in-line electron gun (6) that is arranged in a line along the horizontal axis of the panel (1) and emits three electron beams corresponding to red, green, and blue. has been done. Further, a shadow mask (5) having a curved main surface with one of a number of through holes is disposed close to and opposite to the screen (4). The peripheral part of the shadow mask (5) has a skirt part (8) that is bent according to the outer shape of the panel. In addition, the mask frame (7) is locked with a bottle (not shown) embedded in the inner wall of the panel (1) via a spring (9).In such a color picture tube,
The three electron beam members emitted from the electron gun (6) are deflected by a deflection device (not shown) placed outside near the funnel (2), and are deflected by a substantially rectangular panel (1).
The colors are sorted through the through holes of the shadow mask (5) so as to scan a rectangular area corresponding to the image, and the colors are projected onto the striped phosphors of each color in the correct manner to produce a color image. Here, the effective amount of electron beam passing through the hole of the shadow mask (5) is 1/3 J21 or less due to its mechanism, and the remaining electron beam impinges on the shadow mask and is converted into thermal energy, sometimes up to about 80C. Heat up the shadow mask. Shadow mask (5) is generally O~1
Made of so-called cold-rolled steel whose main component is iron, the coefficient of thermal expansion at 00C is 1.2 x 10 /C, and the thickness is 0.
．． The mask frame is made of a thin plate with a thickness of 1" to 0.31XI+ and supports the skirt part (8) of this shadow mask (5). Therefore, the heated shadow mask (5) easily undergoes thermal expansion, but the surrounding area is blackened and has a large heat capacity mask frame. (Because it is in contact with the force, heat moves from the area around the mask to the mask frame due to radiation and conduction, and the temperature around the shadow mask becomes lower than the center. Therefore, the temperature at the center and periphery of the shadow mask (5) A so-called doming phenomenon occurs in which the temperature difference occurs and heating and expansion occurs mainly in the center.As a result, the Nyadoku mask (5) and the phosphor screen (4)
This changes the distance between the electron beam and the electron beam, disrupting the accurate landing of the electron beam and causing deterioration of color purity. This phenomenon is particularly noticeable in the early stages of operation of a color picture tube. In addition, when a high-brightness image is partially projected on the image plane, and especially when this high-brightness image part is stopped for a certain period of time, an electron beam with a high electron current density is partially generated in the shadow mask. This causes a local doming phenomenon.

Regarding the doming phenomenon of color picture tubes,
A layer made of glass, for example, lead-borate glass, is formed on the main surface of the shadow mask (5) on the electron gun side to absorb the heat generated by the lead-borate glass that the electron beam [alpha] strikes. A proposal to suppress the transmission to the shadow mask (5) was made in Japanese Patent Application No. 148843/1983 by the same applicant as the present invention.

This lead borate glass layer is made of lead borate glass which is dissolved in a butyl acetate alcohol solution containing several grams of nitrocellulose before the panel (1) and funnel (2) are sealed together. The composition is applied to the electron gun side of the shadow mask (5), and after drying, this shadow mask (5) is applied to the panel (1).
Attach it inside. After that, the panel (1) and the funnel (2) are placed on a predetermined frame, and the temperature is raised at a heating rate of, for example, 1007 minutes, and the furnace is heated to a maximum temperature of about 440° for a holding time of 35 minutes or more. , a vitrified lead borate glass layer can be formed on the electron gun side of the shadow mask (5).

A color picture tube incorporating this shadow mask exhibits good characteristics with no doming phenomenon.

However, it has been found that if a color picture tube is manufactured simply by using this technique in a conventional manner, undesirable phenomena may occur in some cases.

That is, the mask material is formed, the mask is welded to the frame as necessary, and the main surface of the mask on the electron gun side 1 - #tan 1 horse shi kasu kasu kasu 1 le qin ta 1 ~ ha ke - bone The fluorescent surface is exposed and developed using the method described above, and in the subsequent process, the composition is fired with the panel and mask combined to form a glass layer. Mis-landing is likely to occur. This is thought to be because the mask is deformed due to variations in the degree of sintering of the glass layer due to variations in firing conditions, resulting in misalignment with the phosphor obtained by exposure and development.

Furthermore, if a defect in glass firing of the mask occurs in a later process, the panel that has already undergone the exposure and development process will also be defective, resulting in large process losses.

Additionally, if the mask glass is fired at the same time as the sealing glass is heated and fired in the process of sealing the panel and the funnel, some of the composition may fall into the tube during firing, causing an undesirable accident. Cheap.

[Purpose of the invention]

The present invention has been made to improve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide an improved method of manufacturing a color picture tube with fewer drawbacks.

[Summary of the invention]

The present invention involves a step of molding a mask material having a main surface with a large number of through holes into a predetermined shape, and heating and baking the main surface of the shadow mask on the electron gun side to cause an expansion smaller than the expansion coefficient of the shadow mask material. There is a process of depositing a composition that will become a glass layer of the coefficient, a process of firing this composition to form a glass layer, and after this process, the panel and mask are assembled using the usual method. 1. A method of manufacturing a color picture tube, comprising a step of forming a fluorescent surface.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 and 2. The component structure of the color picture tube of the present invention itself is the same as that shown in FIG. 1, so a detailed explanation will be omitted.

In a color picture tube as shown in FIG. 1, a shadow mask (5) disposed close to and facing a phosphor screen (4) has a glass material on its main surface on the electron gun side, for example. A layer of lead borate glass is formed. - This lead borate glass layer is made by applying lead borate glass dissolved in a butyl acetate alcohol solution containing several percent nitrocellulose to the electron gun side of the shadow mask (5), and after drying the panel temperature When the electron beam is passed through a furnace where the angle is about 440° and the holding time is 35 minutes or more, a vitrified lead-borate glass layer can be formed on the electron gun side of the shadow mask (5). This lead borate glass has a PbO weight percent of 44~
Vitrification occurs in the range of 93 inches, but 70 to 85 inches is stable against crystallization, and this range is suitable for mass production.

Furthermore, in general, when sealing metal and glass, it is necessary to prevent excessive strain from being applied to the glass. The compressive strength of glass is approximately 10 times the tensile strength.
Therefore, it is preferable that a slight compressive stress is applied to the glass after sealing, so it is preferable that the thermal expansion of the sealing metal is slightly larger than the thermal expansion of the glass. Generally, the thermal expansion coefficient of the shadow mask (5) made of cold-rolled steel material is about 1.2 x 10 /C, but the thermal expansion coefficient of the lead borate glass with the PBO weight percent of 70 to 85 is 0.7 to 1.2 x 10-'/C,
It is very effective for sealing to the cold rolled steel plate shadow mask.

In this way, ZnO or CuO may be added to the lead borate glass as necessary to achieve the permeability crystallization under conventional sealing furnace conditions. In this case, it becomes possible to crystallize at a lower temperature without significantly changing the coefficient of thermal expansion.

When the color picture tube according to configuration C2 as described above is operated, the heat generated in the lead borate glass that the electron beam strikes is absorbed by the heat conductivity of the lead borate glass, which has a thermal conductivity of 6 W/m- Since the shadow mask made of cold-rolled steel plate has an IA of about 100 Ω, the amount of heat transmitted to the mask is small, and the temperature rise of the shadow mask can be effectively suppressed.

When such a color picture tube is operated, the doming phenomenon is effectively suppressed, but if a glass layer with a high specific gravity is formed on the main surface of the shadow mask, it may become easy to vibrate. That is, vibrations from the outside using the skirt portion of the shadow mask as a fixed end, such as high output of low frequency speakers of a television set, may become a cause of vibrations.

In general, the maximum displacement J due to pressure of a simply supported beam is:

384 X E Therefore, if the weight of the main surface of the mask increases, the displacement J due to vibration may also increase.

In such a case, the rigidity of the shadow mask as a whole can be increased by forming, for example, a layer made of lead borate glass extending from the main surface of the shadow mask to the peripheral skirt portion. By doing so, it is possible to sufficiently prevent vibrations of the shadow mask caused by speaker output or the like.

As another example, if a lead-borate glass layer is formed on the screen (47 side) of the shadow mask (5), the effect of suppressing heat transfer as described above will be reduced. Since the specific gravity of the shadow mask is 6.5, which is close to that of the Nyadou mask, forming the lead-bolate glass layer increases the quality of the shadow mask and can effectively reduce the doming phenomenon. It is also preferable to form the glass layer up to the skirt part.Generally, the surface of the shadow mask is covered with a dot-colored oxide film, but this black oxide film not only improves heat dissipation from the shadow mask, but also improves the sealing with the glass. On the other hand, as a shadow mask material, materials that are difficult to form an oxide film, such as umber material (36%
When a lead borate glass layer is formed on the surface of a Ni-Fe alloy), there is no black layer on the surface and heat dissipation is poor.
If a black pigment such as Mn0t or Co2O3 is added to the lead borate glass in advance, a black lead borate glass layer is formed, thereby improving heat dissipation. Furthermore, since the sealing between the glass and the metal results in a strong chemical bond, it goes without saying that the possibility of lead borate glass falling off from the mask is extremely low.

Now, a method for manufacturing a color picture tube having the above configuration will be explained.

] As the first factor, a shadow mask material having a glossy main surface with a large number of through holes (51) perforated by a conventional method is used.

Press mold along the inner surface of the panel. The peripheral edge of the main surface (5) has a skirt portion (8) attached to the side surface of the panel via a mask holder.The skirt portion (8) is provided with a frame (force) as required.

Next, after blackening the shadow mask, a composition containing about 75% by weight of PbO, about 9% of B,0. A glass layer (52) is formed by applying 430C and firing for 35 minutes.Next, the panel for forming a fluorescent surface and the mask on which the glass layer is formed are combined,
After the exposure and development steps, a color picture tube is manufactured using the usual method.

〔Effect of the invention〕

As described above, in the present invention, a fluorescent surface is formed by combining a panel and a mask after completing the firing process of the composition for forming a glass layer, so even if the mask is deformed due to firing the composition, the electron beam can There is no problem of mis-landing. In addition, the masks used in combination in the exposure and development processes are:
Only materials that pass the glass layer formation process are used, so conventional exposure is not required.

Panel defects caused by defects in the formation of the glass layer of the mask that occur after the development process are eliminated, and process losses are reduced.

Furthermore, accidents caused by the composition falling into the tube, which conventionally occurred during firing of the glass composition, are eliminated.

Moreover, it has the effect of preventing mask doming as a color picture tube having a mask formed with a conventional glass layer.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the structure of a color picture tube, and FIG. 2 is a schematic sectional view of a Nyadoku mask.

Claims (1)

[Claims] (1) A process of forming a shadow mask material having a main surface with a large number of through holes into a predetermined shape, and heating and baking the main surface of the shadow mask on the electron gun side to create an expansion coefficient smaller than that of the shadow mask material. There is a process of temporarily adhering a composition that will become a glass layer, a process of firing this composition to form a glass layer, and after this process a panel and a mask are combined using the usual method to fluoresce. 1. A method for manufacturing a color picture tube, comprising the step of forming a surface.