JPS6311737B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing a thin film of heat absorbing material in a color picture tube, and more specifically, an apparatus for depositing a thin film of heat absorbing material on a light reflective metal thin film deposited on the inner surface of a glass face plate. It is related to.

The phosphor surface of a normal color picture tube is coated on a phosphor film attached to the inner surface of a glass face plate (hereinafter referred to as "panel") that constitutes a part of the tube body of the picture tube. A so-called metal back structure in which a light-reflecting metal thin film is deposited to effectively extract emitted light to the front of the color picture tube is common.

FIG. 1 is a cross-sectional view schematically showing the picture tube,
A phosphor film 2 is formed on the inner surface of the panel 1a which is a part of the envelope 1, and a light reflective metal thin film 4 is deposited to cover the phosphor film 2. A shadow mask 6 is isolated from the thin film 4 for a certain period of time.
is located. Further, an electron gun 7 is arranged in a so-called normal network portion 1b of the envelope 1, and many electron beams emitted from the electron gun 7 collide with a shadow mask 6. The collision energy becomes heat, and the temperature of the shadow mask 6 increases. As a result, the shadow mask 6 thermally expands, and the position where the fluorescent surface of the electron beam emits light is shifted. That is, a doming phenomenon occurs. The color shift that occurs along with this phenomenon is called mislanding, and when this mislanding occurs, the color image quality deteriorates. Therefore, in order to reduce mislanding as shown in FIG. Efforts are being made to suppress the expansion. As this heat absorbing material thin film 5, a blackened aluminum thin film is generally used, and its formation method is
This will be explained with reference to the figures.

A panel 1a on which a light reflective metal thin film 4 is deposited,
One or more evaporation sources 8 formed into a basket shape using three or four twisted tungsten wires.
supported at a predetermined position within a vacuum envelope 9 having
The temperature of the evaporation source 8 is raised in a vacuum of 0.1 to 0.5 Torr, and the aluminum wire 10 is melt-evaporated onto the surface of the light-reflective metal thin film 4 to form the heat-absorbing substance thin film 5.

Since the above method uses a coil made of tungsten wire as the evaporation source 8, it has a drawback of short life. In addition, each time another panel 1a is deposited, the inside of the device comes into contact with the atmosphere, and a large amount of gas is adsorbed, so it takes a long time to reach the desired degree of vacuum. It was necessary to prepare many similar devices. Also,
In the latter case, there will inevitably be differences in characteristics between each device, and there will be large variations in the thickness distribution, light reflection efficiency, and heat absorption efficiency of the deposited film formed, and a large number of devices will be required. However, there were disadvantages such as an increase in the number of malfunction maintenance cases and a longer maintenance time.

In order to solve one of the above drawbacks, which is that the heating element has a short lifespan, a means of using a resistance heating element in place of the tungsten wire coil was devised.
It is put into practical use. As a resistance heating element, one whose main component is boron nitride is generally used.
It is difficult to form this type of resistor into a basket shape similar to a tungsten wire coil during molding. For this reason, as shown in FIG. 3, the resistance heating body 13 is shaped like a rectangular parallelepiped and has a so-called boat-like structure in which a recess 13a is formed on the upper surface. Note that the recess 13a may not be provided and may simply be a flat surface. In addition, to solve the problem of requiring a large number of devices and taking a long time to reach a vacuum, the light-reflecting metal thin film 4 and the light-reflecting metal thin film 4 can be solved by arranging functionally divided vacuum chambers in series. An apparatus for continuously depositing the heat-absorbing substance thin film 5 has been devised and put into practical use.

The above device will be explained below with reference to FIG.
A series of vacuum chambers, ie, a vacuum envelope entrance chamber 11a, a light-reflective metal thin film deposition chamber 11b, a heat-absorbing substance thin film deposition chamber 11c, and a vacuum envelope outlet chamber 11d, are shown in series, and the entrance and exit portions of these chambers are respectively marked. A vacuum valve 12a is provided, a gate valve 12b is interposed at the joint between each chamber, and exhaust equipment (not shown) is connected to each chamber depending on the desired degree of vacuum. Furthermore, a resistance heating body 13 whose main component is boron nitride and an automatic vapor deposition material inserter 14 are provided at predetermined positions in the two vapor deposition chambers 11b and 11c. By providing such a resistance heating element 13, the drawbacks of the short life of the tungsten wire coil conventionally used as an evaporation source and the need to replenish the evaporation material each time are eliminated, and it is possible to perform evaporation continuously for a long time. Summer.

Hereinafter, the case of depositing the heat absorbing material thin film 5 will be described. 1a is panel, 2 is this panel 1
A fluorescent film adhered to the inner surface of a, 3 is this fluorescent film 2
An intermediate film formed from a film lacquer material containing an organic substance as a main component to smooth the surface of the film, and is then removed by baking. The panel 1a on which the interlayer film 3 has been formed is carried into the entrance chamber 11a by opening the vacuum valve 12a.
Close a and open the inlet chamber 11a and outlet chamber 11d by 0.05~
Create a vacuum of 0.01 Torr. Next, the gate valve 12b
is opened, the panel 1a of the entrance chamber 11a is transported to the deposition chamber 11b which is always in a vacuum state, the gate valve 12b is closed, and the degree of vacuum in the deposition chamber 11b is set to 1 to 2×10 ^-4 Torr.
Then, the required amount of light-reflective metal is deposited. On the other hand, the vacuum valve 12a is opened by setting the inlet chamber 11a and the outlet chamber 11d to atmospheric pressure, and the panel 1a on which another interlayer film 3 has been formed is carried into the inlet chamber 11a, and the vacuum valve 12a is opened.
Close the inlet chamber 11a and outlet chamber 11d to 0.05~
Create a vacuum of 0.01 Torr. On the other hand, the vapor deposition chamber 11b
A necessary amount of light-reflective metal is deposited on the panel 1a of the chamber 11c, and a heat-absorbing material thin film 5 is deposited on the panel 1a of the deposition chamber 11c. As a method, the pressure in the vapor deposition chamber 11c is adjusted to a degree of vacuum of 0.1 to 0.5 Torr, and electricity is supplied to the resistance heating element 13 installed at a predetermined position, so that the heating temperature is set to about 1500°C. Next, the aluminum wire 10 is inserted from the automatic vapor deposition material inserter 14, and the heat absorbing material thin film 5 is vapor deposited by melting and vaporizing the aluminum wire 10. After the vapor deposition is completed, the gate valve 12b is opened, and the panel in the vapor deposition chamber 11c is placed in the outlet chamber 11d, and the panel 1 in the vapor deposition chamber 11b is placed in the outlet chamber 11d.
a to the vapor deposition chamber 11c, panel 1a of the entrance chamber 11a
are respectively conveyed to the vapor deposition chamber 11b and connected to the gate valve 12b.
Close. Next, each vacuum valve 12a is opened to make the inlet chamber 11a and the outlet chamber 11d atmospheric, and the outlet chamber 11d is opened.
The panel 1a is carried out of the vacuum envelope 9, and the vapor deposition process is completed. Further, a panel 1a on which another interlayer film 3 is formed is carried into the entrance chamber 11a, and the above-described steps are repeated.

The above process has the following problems. That is, the thickness distribution of the heat-absorbing material thin film 5 is thick at the center of the panel 1a and thin at the periphery. An example of the distribution of the deposited film is as shown by curve a in FIG. 5, where the film thickness ratio between the central part (origin 0) and the peripheral part is as large as 6:1. In the experiment, the brightness increased as the heat absorbing material thin film 5 increased by 1000 Å.
It is recognized that the reduction is 7.5%, and if the film thickness is greater than necessary, the energy of electrons will be reduced in the heat-absorbing material thin film 5, resulting in a decrease in the brightness of the color picture tube. Additionally, there are drawbacks such as an increase in the brightness difference between the center and periphery of the panel, and the heat-absorbing thin film 5 used to reduce mislanding causes another problem of reduced brightness. In order to solve this problem, the following method has been adopted to deposit the heat-absorbing material thin film 5 with a uniform thickness distribution. In FIG. 4, the steps of applying a phosphor to the inner surface of the panel 1a, drying it to form a phosphor film 2, and further forming an intermediate film 3 thereon are the same as in the conventional case. . Furthermore, the timing for conveying the finished panel 1a to be vapor-deposited and setting the vacuum or pressure relief conditions in the vacuum envelope are the same as in the conventional case. In the heat-absorbing material thin film deposition chamber 11c, as a means to make the deposition distribution uniform, as shown in FIG. A shield 15 made of stainless steel plate with a diameter of 180 mm and an upward arc of 230 mm is placed directly above the central part of the resistance heating element 13, which is 200 mm in the middle, and the resistance heating element 13 is heated to approximately 1500°C. 10 is inserted and allowed to evaporate and scatter. At this time, the heat-absorbing material thin film 5 that evaporates and scatters more directly above the resistance heating element 13, that is, in the center of the panel 1a, is a part of the aluminum that evaporates and scatters more in this area because the shield 15 is arranged. adheres to the shield 15,
The other components are dispersed and coated on the light reflective metal thin film 4 with a substantially uniform film thickness distribution as shown by line b in FIG. A thin film 5 of heat absorbing material is deposited.

However, if the position of the shield 15 is moved several mm or more from directly above the resistance heating element 13 due to vibrations during deposition or an installation error when starting the apparatus, more aluminum evaporates and scatters to the center of the panel 1a, and the aluminum is deposited on the shield 15. The film is not adhered, resulting in an uneven film thickness distribution as shown by curve C in FIG. The above-mentioned tendency is more noticeable in the long side direction C of the panel than in the vertical direction A and the panel short side direction B shown in FIG.

This type of uneven film thickness distribution causes a localized reduction in brightness, so whenever this phenomenon occurs, the evaporation equipment must be stopped, the vacuum condition returned to atmospheric pressure, and readjustment performed. It takes a long time to return to vacuum.

This invention has been made in view of the above-mentioned drawbacks, and provides an apparatus for manufacturing a heat-absorbing substance thin film in a color picture tube, which is capable of adjusting the setting position of a shield during the deposition of a heat-absorbing substance thin film in a vacuum state. This is what we provide.

An embodiment of this invention will be described below. FIG. 9 is a block diagram schematically showing the main parts of a vapor deposition apparatus used in an embodiment of the present invention. When the heat-absorbing substance thin film 5 is deposited, the change in the deposited film thickness distribution due to the positional shift of the shield 15 appears conspicuously in the long side direction of the panel, as shown in FIG.
In this embodiment, the setting position of the shield 15 can be adjusted only in the long side direction of the panel from the outside of the heat-absorbing substance thin film deposition chamber 11c. The adjusting device 20 connects the shield support rod 16 to a gear mechanism 21.
The operating rod 17 is connected to the operating rod 17 via a handle 18, and a handle 18 is provided at the outer end of the operating rod 17. That is, the set position of the shield 15 is adjusted in the long side direction C of the panel by rotating the handle 18 while looking through the viewing window 19. of course,
It is clear that the operation rod 17 and the vapor deposition chamber 11c are vacuum sealed.

In this embodiment, the setting position of the shield 15 is horizontal and can be adjusted only in the long side direction of the panel, but it can also be configured to be adjustable in the short side direction or up and down direction of the panel as necessary. . Also,
The operating rod 17 can also be electrically driven by a motor.

As described above, according to the present invention, the setting position of the shield can be adjusted from the outside of the vacuum envelope, so there is no need to return the vacuum state to atmospheric pressure for this adjustment, and it is not necessary to return the vacuum state to atmospheric pressure. The time required for returning to vacuum is saved.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining a color picture tube, Fig. 2 is a schematic configuration diagram of a conventional heat-absorbing substance thin film deposition apparatus using a tungsten wire coil as an evaporation source, and Fig. 3 is a sectional view for explaining a color picture tube. The figure is a perspective view of a boat-shaped resistance heating element whose main component is boron nitride, and Figure 4 is a perspective view of a boat-shaped resistance heating element whose main component is boron nitride. A configuration diagram schematically showing an example of a vapor deposition apparatus for depositing a thin film of heat absorbing material, FIG. 5 is a curve diagram showing the film thickness distribution of a thin film of heat absorbing material, and FIG. 6 shows a substantially uniform thin film of heat absorbing material. Fig. 7 is a curve diagram showing that the heat-absorbing material thin film becomes uneven due to the positional shift of the shield, and Fig. 8 shows the position of the shield. FIG. 9 is a schematic diagram showing the movement based on the panel, and is a configuration diagram showing an embodiment of the present invention. 1a... Glass face plate, 2... Fluorescent film, 4... Light reflective metal thin film, 5... Heat absorbing material thin film, 9... Vacuum envelope, 13... Resistance heating element, 15...
Shielding object, 20...adjustment device.

Claims (1)

[Claims] 1. Resistance heating with a flat or concave evaporation material placement part for a color picture tube with a fluorescent surface in which a phosphor film is formed on the inner surface of the face plate and a light reflective metal thin film is formed thereon. A shield is placed between the resistive heating body and the plate directly above the center of the resistance heating body, and a portion of the heat-absorbing substance that evaporates and scatters directly above the center of the resistance heating body is evaporated by the shield. In the apparatus for producing a heat absorbing substance thin film, which vacuum evaporates a heat absorbing substance thin film almost uniformly on the light reflective metal thin film while adhering to the light reflecting metal thin film, the setting position of the shielding member is adjusted from outside the vacuum envelope. 1. An apparatus for producing a thin film of heat-absorbing material for a color picture tube, characterized in that it is provided with an adjustment device.