JPS6141095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a metal thin film on the fluorescent surface of a color cathode ray tube having a metal back structure.

The fluorescent surface of a normal color cathode ray tube is attached to the inner surface of a glass face plate that forms part of the tube body, and the light emitted from this surface is effectively directed to the front of the color cathode ray tube. It has a so-called metal back structure in which a light-reflecting metal thin film is formed for extraction.

The phosphor surface of this metal back structure has the advantage of increasing the brightness of the color cathode ray tube and reducing ion burnout of the phosphor surface. The manufacturing process will be explained with reference to FIG.

In Fig. 1, 1 is a glass face plate, 2 is a fluorescent film coated on its inner surface, and 3 is an intermediate film formed of a filming lacquer material mainly composed of an organic substance to smooth the surface. , 4 is an aluminum thin film. This aluminum thin film 4 is formed by vacuum evaporating aluminum onto the intermediate film 3. The intermediate film 3 is finally removed by baking.

Conventionally, in order to form the aluminum thin film 4 by vapor deposition, as shown in FIG.
The glass face plate 1 formed with
Supported at a predetermined position on a vacuum vessel 6 having one or more evaporation heaters 5 formed into a basket shape using twisted tungsten wire,
A method is used in which aluminum is deposited on the intermediate film 3 in a vacuum of 10 ^-4 torr. However, this method requires replenishment of aluminum, which is the evaporation material, each time, which is time-consuming.Also, since a tungsten wire coil is used as the evaporation heater 5, the surface of the tungsten wire is alloyed with aluminum. The drawback was that it deteriorated and had a short lifespan.

In order to solve this problem, a method of using a boat-shaped resistance heating element in place of the tungsten wire coil has been proposed and put into practical use. As this resistance heating element, one whose main component is boron nitride is generally used.

As shown in FIG. 3, this type of resistance heating element has a so-called boat-like structure in which a recess 7a serving as a deposited material placement part is formed on the upper surface of a resistance heating element 7 in the shape of a rectangular parallelepiped or square bar. Note that there is also a flat surface without the recess 7a.

A continuous evaporation film manufacturing method when the evaporation heater 5 is used as the resistance heating body 7 whose main component is boron nitride will be explained with reference to FIG.

In FIG. 4, 1 to 4 and 7 indicate the same parts as in FIGS. 1 and 3, and 8 is a vacuum envelope, which is composed of an inlet chamber 8a, an aluminum deposition chamber 8b, and an outlet chamber 8c. 9 is a linear vapor-deposited metal material inserter;
Reference numeral 10 indicates a linear vapor-deposited metal material (for example, an aluminum wire, which will be explained below) inserted into the inserter 9. Reference numerals 11 and 12 indicate gate valves, respectively.
The glass face plate 1 with the interlayer film 3 formed thereon is carried into the inlet chamber 8a by opening the gate valve 11, and the inlet chamber 8a and outlet chamber 8c are heated to a pressure of 0.05 to 0.01 torr using an exhaust device such as a vacuum pump (not shown). The aluminum deposition chamber 8b is brought to a vacuum of 1 to 2×10 ⁻⁴ torr. Next, the gate valve 12 is opened, the glass face plate 1 is transported to a predetermined position in the aluminum deposition chamber 8b, and the gate valve 12 is closed. Resistance heating element 7
is installed at a predetermined position at the bottom of the aluminum evaporation chamber 8b, and the aluminum wire 10 which is the evaporation material is
is inserted into the recess 7a of the resistance heating element 7 using the inserter 9. At this time, the resistance heating element 7 passes a current to approximately
It is heated to 1350 to 1500°C, and the aluminum wire 10 melts and evaporates due to the heat, and scatters upward.
This evaporation forms an aluminum thin film 4 on the intermediate film 3.
is formed. At this time, in order to control the amount of aluminum evaporated to the amount necessary for a color cathode ray tube, the speed and time of automatic insertion of the aluminum wire 10, and the temperature of the resistance heating element 7 are adjusted.

Next, open the gate valve 12 to open the aluminum deposition chamber 8.
the glass face plate 1 of b to the exit chamber 8c;
The glass face plate 1 in the inlet chamber 8a is transferred to the aluminum deposition chamber 8b, and the inlet chamber 8a and outlet chamber 8c are brought to atmospheric pressure, and the glass face plate 1 in the outlet chamber 8c is carried out to the outside of the vacuum envelope 8 to undergo the vapor deposition process. Complete. At the same time, the next glass face plate 1 is carried into the entrance chamber 8a and the above steps are repeated.

In the method described above, in which the aluminum wire 10 is inserted into the inserter 9 during vapor deposition on the glass face plate 1 which is the object to be vapor deposited, and the amount of vapor deposition is controlled by the speed, time, and temperature of the resistance heating element 7. Since the aluminum wire 10 is in a stopped state during times other than vapor deposition, such as when transporting the plate 1, the tip of the aluminum wire 10 melts into a bead shape due to the heat of the resistance heating element 7, as shown in FIG. . Further, since the aluminum has evaporated and no aluminum remains in the recess 7a of the resistance heating element 7, the next glass face plate 1 is carried in and the aluminum wire 10 is deposited on the recess 7a. Even if inserted, aluminum wire 1
0 slides in the recess 7a and comes off from the resistance heating element 7 without being melted and evaporated. Furthermore, even if it melts, it forms a bead in the recess 7a due to its surface tension, making it impossible to utilize the heat of the resistance heating element 7 effectively, and it takes a long time for it to evaporate.

This invention was developed in view of the above points, and when a boat-shaped resistance heating element mainly composed of boron nitride is used as an evaporation source, the aluminum wire easily melts and evaporates to form a desired aluminum thin film. The present invention provides a method for forming a color cathode ray tube. An embodiment of the present invention will be described below with reference to FIG.

FIG. 6 is a time chart showing the insertion, retraction, and stop states of the linear vapor-deposited metal material inserter 9 shown in FIG.

In this operation, the glass face plate 1 on which aluminum has not yet been deposited is carried into the aluminum deposition chamber 8b, and after a predetermined degree of vacuum is reached, deposition is started. At this point T ₁ is the aluminum wire 10
At the time of insertion. At this time, aluminum wire 10
Since the tip was located away from the resistance heating element 7 as will be described later, it did not have a bead shape as in the conventional case shown in FIG.

Therefore, the tip of the aluminum wire 10 is placed in the recess 7.
When it reaches a temperature and melts, its heat capacity is small, so
Dissolves quickly. At this time, it forms a bead shape on the recess 7a, but since its volume is extremely small, its heat capacity is small, and the temperature rapidly rises due to the heat of the resistance heating element 7, the surface tension decreases, and it spreads over the entire surface of the recess 7a. Once aluminum spreads over the entire surface of the recess 7a, even if the aluminum wire 10 is continuously inserted, when it comes into contact with the resistance heating element 7, it will instantly melt, diffuse, and evaporate. The aluminum wire 10 is continuously inserted from the deposition start point T ₁ to the deposition end point T ₂ .

After the aluminum wire 10 is inserted until the desired amount of aluminum is deposited, it is retreated to a position where its tip will not be melted by the heat of the resistance heating element 7. This point is _T3 .

In this embodiment, as the above-mentioned retraction method, the drive shaft of the inserter 9 is reversed from the time T ₂ to the time T ₃ to retract the same path as that at the time of insertion.

The glass face plate 1 on which aluminum vapor deposition has been completed by the above method is placed in the aluminum vapor deposition chamber 8b.
A desired aluminum thin film can be formed by carrying out the next new glass face plate 1 and repeating the above vapor deposition.

In the above embodiment, the case of aluminum vapor deposition was explained, but the present invention can be similarly used when aluminum is vapor deposited in a gas atmosphere or in a low vacuum to obtain a blackened aluminum film.

It can also be used when metals other than aluminum are vapor-deposited to create light-reflective metal thin films and blackened films.

As explained above, according to the present invention, the aluminum wire can be easily melted and evaporated by simply moving the tip of the aluminum wire away from the resistance heating element after the completion of vapor deposition, and an aluminum vapor-deposited thin film with stable uniformity can be obtained. There is.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining the manufacturing process of forming a predetermined metal thin film on the inner surface of a glass face plate, Fig. 2 is a cross-sectional view of a conventional apparatus for forming the metal thin film shown in Fig. 1, and Fig. 3 4 is a perspective view of a boat-shaped resistance heating element, and FIG. 4 is a schematic cross-sectional view of a part of a conventional apparatus for forming a predetermined metal thin film on the inner surface of a glass face plate using the resistance heating element of FIG. 3. , FIG. 5 is a perspective view for explaining the drawbacks of the device shown in FIG. 4, and FIG. 6 is a time chart showing an embodiment of the present invention. In the figure, 1 is a glass face plate, 2 is a fluorescent film, 3 is an intermediate film, 4 is an aluminum thin film, 7 is a resistance heating element, 7a is a recess, 8 is a vacuum envelope, 8a is an entrance chamber, and 8b is aluminum evaporation chamber, 8c is an exit chamber, 9 is an inserter, 10 is an aluminum wire, 11,
12 is a gate valve. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A flat plate or rectangular bar-shaped resistance heating body having a flat or concave evaporation material placement part is used as an evaporation source, a linear evaporation metal material is supplied to the evaporation source by a supply device, and a color cathode ray tube fluorescence is produced. In a method of vacuum-depositing a metal thin film on a surface part, the linear vapor-deposited metal material is supplied to an evaporation source to perform vapor deposition, and immediately after the completion of the vapor deposition, the leading electrode of the linear vapor-deposited metal material is removed from the surface of the resistance heating body. A method for forming a vapor deposited film on a color cathode ray tube, which is characterized by separating the film from the vapor deposited film.