JP2697652B2 - Method and apparatus for forming heat absorbing film of color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a heat absorbing film on a metal back film deposited on the inner surface of a panel of a color picture tube.

[0002]

2. Description of the Related Art The structure of a phosphor screen of a color picture tube, which has been generally used in the past, is based on a phosphor film adhered to an inner surface of a panel constituting a part of a tube of the picture tube. It has a so-called metal back structure in which a light-reflective metal film is deposited to effectively extract the emitted light to the front of the color picture tube.

FIG. 3 is a sectional view schematically showing the structure of a general color picture tube.

As shown in FIG. 3, a color picture tube mainly comprises a funnel 310b and a panel 310a.

[0005] At predetermined positions on a black film made of graphite, which is called a black matrix film 320, on the inner surface of the panel 310a, a phosphor film 330 of minute dots composed of green, blue and red phosphors is formed. And the phosphor film 3
A filming film 340 made of an organic emulsion is formed to smooth the surface of the phosphor 30, and a phosphor film 330 is formed.
Metal back film 350 is deposited so as to cover
A shadow mask 370 having a large number of minute holes is arranged at a certain distance from the metal back film 350. An electron gun 380 is disposed at a portion of the farnel 310b called a normal neck portion 310c.
Many electron beams emitted from 0 are shadow mask 3
Collision with 70.

A color image is formed when an electron beam emitted from the electron gun 380 is selected and passed through the fine holes of the shadow mask 370, and a color image is formed.
The electron beam that failed to pass through the shadow mask 37
When it collides with zero, the collision energy becomes heat and raises the temperature of the shadow mask 370. As a result, the position of the minute hole moves due to thermal expansion of the shadow mask 370, and the position at which the electron beam emits light from the phosphor screen shifts (this phenomenon is called a doming phenomenon).

Therefore, in order to reduce the doming phenomenon, a heat absorbing film is formed on the metal back film 350, that is, on the electron gun 380 side.
Has been performed to suppress the thermal expansion by absorbing the heat generated by the heat. It is common to use a blackened aluminum film as the heat absorbing film.

FIG. 4 is a view for explaining a method of forming a heat absorbing film in a conventional color picture tube.

The method for forming the blackened aluminum film in the color picture tube shown in FIG. 4 includes a vapor deposition material automatic inserter 410 for inserting a vapor deposition material and a boron nitride heater 430 for heating the vapor deposition material. A panel 310a in which a metal back film 350 or the like is deposited at a predetermined position in a vacuum envelope 450 having a thickness of 1.33 × 10-1.
Hold under a vacuum of 33 [Pa], and heat the boron nitride heater 430.
, The aluminum pellet material 420 inserted from the vapor deposition material automatic inserter 410 is melted and evaporated, and the blackened aluminum film is deposited on the metal back film 350 as the heat absorbing film 360.

However, in the above-described method for forming a blackened aluminum film in a color picture tube, the thickness distribution of the heat absorbing film 360 made of the blackened aluminum film is such that the panel 310a is close to the vapor deposition material automatic inserter 410 which is a heating deposition source. Is thicker on the central side and thinner on the peripheral side far from the automatic vapor deposition material insertion device 410, which causes a problem of causing uneven brightness of the color picture tube.

FIG. 5 is a view showing a method of forming a heat absorbing film in the method of forming a heat absorbing film shown in FIG. 4 in consideration of equalizing the film thickness distribution of the heat absorbing film.

In the method of forming a heat absorbing film in a color picture tube shown in FIG. 5, a distance between a metal back film 350 deposited on a panel 310a and a boron nitride heater 430 is maintained at a constant distance, and a circular arc is provided therebetween. A stainless steel plate-shaped shield 440 is disposed with the convex surface of the shield 440 facing the boron nitride heater 430 side, and the blackened aluminum film is used as the heat absorbing film 360 in the same manner as in the forming method shown in FIG. It is to be deposited on the metal back film 350.

In this way, a part of the aluminum material, which is largely evaporated and scattered toward the central portion of the panel 310a, is prevented from being attached to the stainless steel plate shield 440, and the others are dispersed and deposited. An equal heat absorbing film can be formed (see JP-A-61-53816).

[0014]

However, in the conventional method for forming a heat absorbing film of a color picture tube as shown in FIG. 5, when a plurality of heatable vapor deposition sources are set, adjacent vapor deposition sources on the inner surface of the panel. The portion corresponding to the middle portion of the film is affected by the respective vapor deposition sources, so that the heat absorption film thickness tends to be large, and the uniformity of the film thickness distribution may be impaired. For this reason, there is a problem that the brightness of the color picture tube is reduced in a thick portion of the heat absorbing film, and uneven brightness occurs in the entire color picture tube.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. Even when a heat absorbing film of a color picture tube is formed by a plurality of evaporation sources, the color picture tube is not required. It is an object of the present invention to provide a method and an apparatus for forming a heat absorbing film of a color picture tube, which can form a heat absorbing film without causing uneven brightness.

[0016]

In order to achieve the above object, the present invention provides a color picture tube in which a heat absorbing film is further deposited under vacuum on the inner surface of a panel having a metal back structure by a plurality of heatable deposition sources. The method of forming a heat absorbing film is characterized in that the heat-depositable evaporation sources are equally divided by a partition member, and the outside air is injected from an end of the partition member on the panel inner surface side.

Further, the invention is characterized in that the gas injected to the inner surface of the panel is nitrogen.

Further, the gas injected to the inner surface of the panel is an inert gas.

A plurality of heat-depositable evaporation sources are provided inside a vacuum chamber having an open end serving as a panel receiver, and a panel having a metal back structure is placed on the panel receiver, and the plurality of heat-depositable vapor deposition sources are placed on the panel receiver. A heat absorbing film forming apparatus for forming a heat absorbing film on the inner surface of the panel by a source, wherein the partition member is provided inside the vacuum chamber and uniformly partitions between the respective heating sources. And an ejection port for ejecting outside air, which is provided at an end on the inner surface side of the panel.

Further, a delay timer circuit for determining a timing at which the outside air is injected from the injection port is provided.

[0021]

According to the present invention having the above-described structure, an injection port is provided at an end portion on the inner surface side of the panel of the partition plate for equally partitioning a plurality of heatable vapor deposition sources. Since the heat absorbing film is deposited on the metal back thin film by the heatable vapor deposition source while being sprayed on the inner surface, the vapor deposition material from the vapor deposition source is dispersed on the inner surface of the panel where the outside air is sprayed from the spray port. Therefore, the heat absorption film is formed substantially uniformly without causing interference between the evaporation sources.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a heat absorbing film forming apparatus suitable for one embodiment of a method for forming a heat absorbing film of a color picture tube according to the present invention.

FIG. 2 is a sectional view of a panel manufactured by the method for forming a heat absorbing film of a color picture tube shown in FIG.

The heat absorbing film forming apparatus for a color picture tube shown in FIG. 1 includes a vacuum chamber 110 having an open end serving as a panel receiving base 140. Both ends are connected to a power source (not shown) inside the vacuum chamber 110. Filament heaters 120a and 120b, which are connected heating source, are provided. A partition plate 1 is provided between the filament heaters 120a and 120b.
30 are provided. Here, the partition plate 130 is installed at a position that evenly partitions the filament heaters 120a and 120b. Further, the inside of the partition plate 130 is
50 is passed out of the vacuum chamber 110.
An electromagnetic valve 160, a leak valve 170, and a filter 180 for controlling the introduction of outside air into the vacuum chamber 110 are attached to a nozzle 150 outside the vacuum chamber 110, and an outside air introduction port which is an end of the nozzle 150. From 190, outside air can be introduced. The solenoid valve 160 is connected to the filament heater 120a by a delay timer circuit (not shown).
And 120b are for introducing outside air after a predetermined time from the energization.

In order to form a heat absorbing film on the inner surface of panel 100 by the above-described apparatus, first, a filament heater 120 is formed.
After supplying the aluminum material to a and 120b, the panel 1
00 is placed on a predetermined position of the panel receiving base 140 forming the vacuum chamber 110.

After the panel 100 is placed at a predetermined position on the panel support 140, the internal pressure of the vacuum chamber 110 is increased to 1.33 × 10
Rotary pump (not shown) to make up to 1.33 [Pa]
This exhausts the air inside the vacuum chamber 110 to the outside.

The internal pressure of the vacuum chamber 110 is 1.33 × 10
When the pressure reaches 1.33 [Pa], the filament heater 12
0a and 120b are energized, the energization signal is sent to the solenoid valve 160 via a delay timer circuit (not shown), and the solenoid valve 160 is activated with a delay from the start of energization of the filament heaters 120a and 120b.

By the above-described operation, the filament heaters 120a and 120a, which are heat-depositable sources,
While the outside air is sprayed to a portion corresponding to the middle portion of b, evaporation of an aluminum material to be a heat absorbing film is performed, and a deposition material from a deposition source is dispersed on an inner surface of the panel 100 where the outside air is injected from the nozzle outlet 155. Therefore, as shown in FIG. 2, the heat absorption film is formed substantially uniformly without causing interference between the heatable evaporation sources.

An example in which a heat absorbing film is formed on a 20-inch panel will be described below.

First, 15 filament heaters per heater
An aluminum material of about 0 [mg] is inserted into the filament heaters 120a and 120b in a cylindrical shape.

The panel 1 on which the metal back film has been formed
00 on the panel support 140, and the inside of the vacuum chamber 110
After evacuating to 33 × 10 to 1.33 [Pa],
100 for filament heaters 120a and 120b
A voltage is applied so that a current of about [A] flows.

At the same time as the start of the voltage application, the delay timer circuit connected to the solenoid valve 160 is operated, so that the solenoid valve 160 is opened one to two seconds after the filament heaters 120a and 120b have completely turned red, and outside air is introduced.

The heat absorbing film is formed by adjusting the amount of outside air introduced by the leak valve 170 to about 0.1 to 0.5 [%] of the pumping speed of the rotary pump.

After the completion of the vapor deposition, the inside of the vacuum chamber 110 is returned to the atmospheric pressure, and the vacuum chamber 110 is sent to a step after a firing step for decomposing an organic substance such as a filming film.

If nitrogen or an inert gas is used as the introduced gas, the oxidation of the filament heater is suppressed, the life of the filament heater is extended, and the number of replacements can be reduced.

In the above embodiment, two filament heaters 120a and 120b are provided. However, in the present invention, the number of filament heaters is not limited to two, and a plurality of filament heaters may be set. It can be implemented. In addition, although the nozzle 150 passes through the inside of the partition plate 130, the nozzle 150 may be provided along the side surface of the partition plate 130 and a jet port of the outside air may be provided so that the distance from each heating deposition is uniform. .

[0038]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, a partition plate for uniformly partitioning each of the plurality of heatable vapor deposition sources is provided, and a nozzle for introducing outside air is provided in each partition plate. In order to deposit the heat absorbing film on the metal back film by the heating evaporation source while injecting the outside air from the nozzle ejection port provided at the tip of the Are dispersed. This makes it possible to form the heat absorbing film substantially uniformly without causing interference between the evaporation sources, and to provide a heat absorbing film that does not cause luminance unevenness of the color picture tube even when a plurality of evaporation sources are set. Can be formed.

According to the second aspect of the present invention, the gas ejected from the nozzle ejection port toward the inner surface of the panel is nitrogen, thereby suppressing oxidation of the heatable vapor deposition source and extending the life of the heatable vapor deposition source. The number of replacements is reduced. Therefore, it is possible to reduce the labor and time required for replacing the heating source.

According to the third aspect, the gas injected from the nozzle injection port toward the inner surface of the panel is made to be an inert gas, thereby achieving the same effect as the second aspect.

According to a fourth aspect of the present invention, a partition member is provided in the vacuum chamber to uniformly partition between the heating sources, and the outside air is jetted to an end of the partition member on the inner surface side of the panel. The same effect as that of the first aspect is provided by providing an injection port for the above.

According to the fifth aspect of the present invention, the heat absorbing film can be formed more accurately and substantially uniformly by providing a delay timer circuit for determining a timing at which the outside air is injected from the nozzle injection port.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a heat absorbing film forming apparatus suitable for one embodiment of a method for forming a heat absorbing film of a color picture tube according to the present invention.

FIG. 2 is a sectional view of a panel manufactured by the method for forming a color picture tube heat absorbing film shown in FIG.

FIG. 3 is a sectional view schematically showing a configuration of a general color picture tube.

FIG. 4 is a view for explaining a method of forming a heat absorbing film in a conventional color picture tube.

FIG. 5 is a diagram showing a method of forming a heat absorbing film in the method of forming a heat absorbing film shown in FIG. 4 in consideration of equalizing the film thickness distribution of the heat absorbing film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Panel 20 Black matrix film 30 Phosphor layer 40 Filming film 50 Metal back thin film 60 Heat absorption film 100 Panel 110 Vacuum tank 120 Filament heater 130 Partition plate 140 Panel receiving stand 150 Nozzle 155 Nozzle injection port 160 Solenoid valve 170 Leak valve 180 Filter 190 Outside air inlet

Claims (5)

(57) [Claims] 1. A method for forming a heat absorbing film for a color picture tube, further comprising: depositing a heat absorbing film on a panel having a metal back structure in a vacuum by using a plurality of heat depositable sources under vacuum. Wherein the partition wall is uniformly divided by a partition member, and outside air is ejected from an end of the partition member on the inner surface side of the panel. 2. The method for forming a heat absorbing film for a color picture tube according to claim 1, wherein the gas jetted to the inner surface of the panel is nitrogen. 3. The method for forming a heat absorbing film for a color picture tube according to claim 1, wherein the gas to be jetted to the inner surface of the panel is an inert gas. . 4. A plurality of heatable vapor deposition sources are provided inside a vacuum chamber having an open end serving as a panel receiving table, and a panel having a metal back structure is placed on the panel receiving table to form the plurality of heatable vapor deposition sources. A heat absorbing film forming apparatus for forming a heat absorbing film on the inner surface of the panel by a source, comprising: a partition member provided inside the vacuum chamber, for uniformly partitioning between the respective heating evaporation sources; and the partition member. Provided at an end on the inner surface side of the panel,
A heat absorbing film forming apparatus, comprising: a jet port for jetting outside air. 5. The heat absorbing film forming apparatus according to claim 4, further comprising a delay timer circuit that determines a timing at which the outside air is injected from the injection port.