JPS60105138A - Manufacture of color picture tube - Google Patents

Abstract

PURPOSE:To prevent deterioration of color purity such as color dispersion and color shade by a method, in which a photosensitive composite is applied to the main face of a shadow mask and exposed, while powder grains mainly composed of glass are contacted with a thin layer after being exposed followed by heating a glass layer for being sintered. CONSTITUTION:Phosphors on the screen 4 are selectively made to luminesce through the shadow mask consisting of the main face and the skirt part 8 extending over the periphery of the main face. In a manufacturing method of a color picture tube provided with an electron gun 6, a photosensitive composite, for instance, diazonium salt or its mixture is applied to one main face of the mask 5 for being made into a thin layer. Next, the thin layer is irradiated by ultraviolet rays for generating a substance having the capacity of accepting powders on the thin layer. Subsequently, lead borate glass grains 14 from a jet device 11 are negatively electrified for being continuously applied to the mask 5. The applied glass layer is heated and sintered, while the mask 5 is mounted inside a panel 1.

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.

[Technical background and problems of the invention]

In general, a shadow mask type color picture tube, as shown in FIG. ).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, while the net (3) is provided with the panel (1). red, arranged in a row along the horizontal axis of
A so-called in-line type electron gun (6) that emits three electron beams (11) corresponding to green and blue is installed inside the screen (4).A large number of through holes are bored in close opposition to the screen (4). A shadow mask (5) having a curved main surface is disposed.A peripheral portion of the shadow mask (5) has a skirt portion (8) that is bent in accordance with the outer shape of the panel,
This skirt part (8) is supported and fixed by a mask frame (7) consisting of a cross-sectional frame, and the mask frame (7) is further connected to the panel (1) via a spring (9).
It is held in place by a pin (not shown) embedded in the inner wall. In such a color picture tube, an electron gun (6)
The three electron beams (, +1) emitted from the funnel (2) are deflected by an external deflection device (1 not shown) near the funnel (2), and are deflected by a rectangular panel approximately 17'jl'l. tl) and through the through hole of the Nyadu mask (5),
A color image is displayed by correctly colliding the light-emitting striped phosphors of each color. Shadow mask here (5)
Due to its mechanism, the η-effect Ichiko beam passing through the hole has 173
The remaining electron beam impinges on the shadow mask and is converted into thermal energy, heating the shadow mask to about 80'C as II ().Shadow mask (5
) generally has a thermal expansion coefficient of 1.2X at 0 to 100℃
It is formed from a thin plate made of so-called cold-rolled steel mainly composed of iron with a thickness of 10=5/'C and a thickness of 1~0.3 mm, and the skirt aIS+8) of this shadow mask (5) The mask frame (7) supporting the is also made of cold-rolled steel with a thickness of approximately 11 m and which has been subjected to a blackening treatment. Therefore, the heated Nyadu mask (5) easily undergoes thermal expansion, but since the surrounding area is in contact with the blackened mask frame (7) which has a large heat capacity, the shadow mask is affected by radiation and transmission. Heat moves from the periphery to the mask frame, and the temperature at the periphery of the shadow mask is 44 degrees lower than at the center. For this reason, a temperature difference occurs between the central portion and the peripheral portion of the shadow mask (5), resulting in a so-called doming phenomenon in which the central portion is relatively heated and expanded.

This results in a shadow mask (5) and a phosphor screen (4).
) changes, the positive 7M1i landing of the electron beam is disturbed, and color purity deteriorates. Such a phenomenon is particularly noticeable in the early stages of operation of a color picture tube. Furthermore, even when a partially high-luminance image is projected, a local doming phenomenon occurs at the corresponding portion of the shadow mask.

Regarding the doming phenomenon of color picture tubes,
Many proposals have been made from the viewpoint of promoting heat radiation from the center of the shadow mask and preventing heat conduction to the shadow mask. For example, US Pat. No. 2,826,538 proposes providing a black layer made of graphite on the surface of the shadow mask in order to promote heat radiation from the shadow mask. In such a color picture tube, this graphite layer acts as a good heat radiator, so that the temperature of the shadow mask is lowered. However, this black material 4 made of graphite also has drawbacks such as flammability. -The adhesion of the black layer deteriorates due to thermal cycles in the thermal process during the manufacturing process of color picture tubes, and when vibrations are applied to the color picture tube, part of it peels off and minute pieces fall off. There are things to do. When observed through a shadow mask, the black layer formed in this way causes pores to become sticky and deteriorate the 11-hole J image (4) on the fluorescent surface, and when applied to an electron gun, causes sparks between the electrodes This causes a significant deterioration in the quality of color picture tubes, such as deterioration of sub-voltage characteristics.As a second example,
- For example, if a porous layer composed of manganese dioxide is
There have been proposed ＋ and '4 constructions in which an aluminum layer is deposited on top of the aluminum layer, and a nickel oxide or nickel iron layer is vacuum-deposited on the aluminum layer. When such a configuration is adopted, the heat generated on the rain burning surface of the electron beam is not transmitted to the mask but is radiated away from the mask because the thermal conductivity coefficient of the porous layer is extremely small. As a result, the upper limit of the temperature of the shadow mask can be effectively suppressed. However, in order to provide three layers on this shadow-1 screen, the manufacturing method is 1 foot 4' 1F, and a huge amount of equipment and work time are required. The drawback is that productivity is significantly lacking.

[Purpose of the invention]

The present invention has been made in view of the above point B, and it is possible to reduce the doming of the shadow mask. -Prevented deterioration of color purity due to color, misalignment, etc.] Secondary i1
It is an object of the present invention to provide a method for manufacturing a color image receptor with high productivity.

The present invention provides an electron gun which is located close to the screen and emits an electron beam through the main surface thereof (a shadow mask having a large number of through holes and which causes the phosphor on the screen to emit light). A method for manufacturing a color picture tube comprising at least a step of applying a photosensitive composition to at least one of the main surfaces of the shadow mask to form a thin layer, and exposing the thin layer to a powder receptive ability. A process that causes
The temperature of the shadow mask can be adjusted by including the steps of bringing powder particles mainly made of glass into contact with the thin layer after exposure, allowing the glass powder particles to be received by the thin layer, and heating and sintering this glass layer. This is a method for manufacturing a color picture tube that is highly industrially premature and capable of suppressing doming of the shadow mask by reducing the doming of the shadow mask.

[Embodiments of the invention]

The present invention will be described in detail below based on examples. still,
The component structure itself of the color picture tube applied to the present invention is the first one.
Since it is the same as that shown in the figure, detailed explanation will be omitted.

A large number of holes can be formed in the shadow mask of a color picture tube as shown in FIG. 1 by selectively etching it using an exposure method. Next, the main surface having a large number of through holes is press-molded into a curved shape, and the peripheral portion is press-molded into a skirt portion for supporting the main surface, thereby completing the shadow mask prototype. After the i-gloss mask (5) is formed into a predetermined shape, its main surface, which becomes a concave surface facing the electron gun when it is disposed close to and facing the screen (4), is mainly made of glass. For example, a layer of lead borate glass is formed. This lead borate glass layer seals the panel (1) and the funnel (2) together with a thin layer of an azonium salt alone or a mixture of a diazonium salt and other substances (a) of the shadow mask 1r8). Powder particles of lead borate glass are applied in contact with the thin layer formed by coating and exposing the subgun side.In this case, the N layer forming substance is dissolved in a solvent such as water or alcohol, and the shadow It is applied to the mask (5) and dried to form a solid thin layer. This thin layer is then irradiated with ultraviolet rays, and the thin layer in the areas exposed to the ultraviolet rays undergoes a photodecomposition reaction of the diazonium salt. , a substance with powder-accepting ability is produced.

On the other hand, various methods can be used to apply a 1" thin layer of lead borate glass that has the ability to accept this powder, but it is important to apply it uniformly and to prevent clogging of the through holes. For example, brush application is undesirable due to the uniformity of the coating film and the risk of clogging of the transparency.Spray application is undesirable due to the risk of clogging of the transparency and uniformity of the coating. Although it is good in terms of hole clogging, the spray time must be set in consideration of the adhesion efficiency of glass particles to the shadow mask.Also, the static coating method has very good adhesion efficiency. This is a preferable law.

Figure 9'S2 shows the equipment 1a for this 1]c9 electrocoating method, in which a wave r (cloth, i.e., shadow mask (5)) is grounded as an anode. 1υ is (vy) Apply V from the current source 0 to the shell voltage, for example -90, and apply the shadow mask (5) and the injection device 1lti.
A high-voltage electrostatic field is formed between n. The lead borate glass particles (14) sprayed from the supply tank (121 through the injection device←υ) are negatively charged, are electrostatically lifted, and can be continuously adhered to the counter electrode shadow mask CF3+. If a thin layer capable of accepting powder is not formed even if it is attached to the non-coated area, such as the mask frame, the μIJ adhesion is very weak and the thin layer can be removed by suctioning air or other means. Needless to say, it can be easily removed. Formation of the glass layer by electrostatic coating increases the adhesion efficiency of negatively charged glass particles adhering to the positively charged shadow mask, resulting in high material loss and extremely low material loss. , there is less risk of clogging of the through holes.Also, if the electrostatic field is kept constant, a highly uniform coating film thickness can be obtained.Furthermore, glass particles are a poor conductor at 1 m, so they are easily charged, and static electricity increases. Suitable for coating methods.

A glass layer is applied as described above, and after drying, this shadow mask (5) is installed inside the panel (1). After that, the panel (1) and the funnel (2) are placed on a predetermined frame and passed through a heat treatment furnace with a maximum temperature of about 440° and a holding time of 35 minutes or more. The vitrified lead can form a borate glass layer on the electron gun side. This lead borate glass vitrifies when the PbO weight percentage ranges from 44 to 93%, but it is stable against crystallization. 70 to 85%, and this range is suitable for producing 1. Furthermore, in general, when sealing metal and glass, it is necessary to prevent excessive strain from being applied to the glass. For glass, its compressive strength is about 10 times the tensile strength.
Therefore, it is preferable that the thermal expansion of the sealing metal be slightly larger than that of the glass, since it is preferable that a slight compressive force is applied to the glass after sealing. Generally, the thermal expansion coefficient of the shadow mask (5) made of a cold-rolled copper plate is about 1.2 x 10''/C, but the shadow mask (5) made of a lead borate glass with a weight percentage of PbO of 70 to 85% is used. The thermal expansion coefficient is 07~1.2X10-VC,
Very suitable for sealing to cold rolled steel plate shadow masks. By the way, in order to crystallize such lead borate glass, a maximum temperature of 400°C to 600°C and a furnace capable of maintaining it for 30 minutes or more are required. ) and the funnel (2) at the same time, if they are crystallized in a mego furnace, or the shadow mask (5) including the shadow mask (5) and the frame (7)
It would be very industrially advantageous if the 1' and 7 bodies could be crystallized simultaneously in the stabilization process.

In this way, ZnO and CuO are added as necessary to achieve crystallization under conventional heat treatment furnace conditions.
Alternatively, it may be added to glass. In this case, it becomes possible to crystallize at a lower temperature without significantly changing the ripening state.

When the color image receiving axis formed and completed as described above is operated, the heat generated in the lead borate glass that the electron beam strikes will be absorbed by the heat conductivity of the lead borate glass, which has a thermal conductivity of 6 W/m. −
Cold rolling (approximately 1/8 of that of the shadow mask of the interplate)
Therefore, the amount transmitted to the mask is reduced, 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: where: L length of the beam between two fixed ends Nv: weight per unit length of the beam 1): Young's modulus ■: beam ■ 2 It is expressed by the second moment. Therefore, if the weight of the main surface of the shadow mask increases, it is possible that the displacement J due to vibration increases.

In such cases, the rigidity of the entire shadow mask can be increased by, for example, forming a layer made of lead borate glass extending from the main surface of the shadow mask to the skirt at the periphery. . In this case, when forming a thin layer that has a powder receptivity, it can be easily selectively formed by appropriately selecting the position of the exposure light source. It is also possible to sufficiently prevent vibrations of the shadow mask.

In another embodiment, if a lead borate glass layer is formed on the screen (4) side of the shadow mask (5), the effect of suppressing heat transfer as described above will be reduced. However, since the specific gravity of this lead borate glass is close to that of 65 binding and dough masks, the formation of lead 11 (salt glass layer) increases the η kick of the shadow mask, and as a result reduces the doming phenomenon. In this case as well, it is preferable to form the glass layer up to the skirt part.Generally, the surface of the shadow mask is coated with a black oxide film by heat treatment, but this black oxide film is This has the effect of not only increasing heat dissipation from the mask, but also improving the bond when sealing with glass.

On the other hand, when a lead borate glass layer is formed on the surface of a material on which it is difficult to form an oxide film as a shadow mask material, such as amber material (36% Ni-Pe alloy), Table 1f
jj has a black layer. <Heat dissipation is poor, but the black face cup 1 to MnO2 or co is preliminarily applied to the lead borate glass.7. r
≦If black lead is added, a borate glass layer is formed, which improves heat dissipation properties. Furthermore, glass and metal f↑
Needless to say, since lead has a strong chemical bond, falling off from the shadow mask of lead-bolate glass is extremely rare.

〔Effect of the invention〕

As described above, according to the present invention, the doming of the shadow mask can be effectively controlled and color purity deterioration such as color shift and color unevenness can be improved without requiring large-scale production steps or increasing work time. The industrial value is extremely high.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a shadow mask type color picture tube, and FIG. 2 is a schematic structural view of an apparatus for explaining an embodiment of the manufacturing method of the present invention. (1)...Panel (2)...Funnel 13)・
・・Neck (4)・・Screen (5)・Nyadou mask (6)・・Electron gun (7)・・Frame

Claims (1)

[Scope of Claims] 1) A shadow mask consisting of a main surface with a large number of through holes adjacent to the screen and a skirt extending around the periphery of the main surface; In the method for manufacturing a color picture tube, the color picture tube is equipped with at least an electric f-gun that emits an electron beam that causes the phosphor on the phosphor to selectively emit light. a step of exposing the thin layer to light to make the thin layer capable of accepting powder; and a step of bringing glass-based powder particles into contact with the exposed thin layer so that the glass powder particles are accepted by the thin layer. A method for manufacturing a color picture tube, comprising the steps of heating and sintering the glass layer formed on the shadow mask. 2) The method of manufacturing a color picture tube according to claim 1, wherein the step of bringing the glass powder particles into contact with the thin layer is performed by electrostatic coating.