JPS63298937A - Forming method of cathode-ray tube fluorescent screen - Google Patents

Abstract

PURPOSE:To carry out an accurate membrane thickness control easily by specifying the rotation speed to the glass panel of each size, when glass panels with different sizes of fluorescent screens are mixed on the same production line. CONSTITUTION:When glass panels having different sizes of fluorescent screens are mixed on the same production line, the rotation speed responding to each size of glass panel is set making proportional to the value of [1/(D/2)]<1/2> where the size of the glass panel is made D. In such a way, an optimum condition for each size can be set easily, and an accurate membrane thickness control for each size of glass panel can be carried out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for forming a fluorescent surface of a negative W7I111 tube, and in particular, after applying a film-forming solution to the inner surface of a glass panel forming a cathode ray tube. This invention relates to a method for forming a fluorescent surface of a cathode ray tube, in which the glass panel is rotated at high speed to shake off excess solution to the outside of the glass panel by centrifugal force, and the thickness of the film on the inner surface of the glass panel is adjusted.

[Background of the Invention] Generally, the fluorescent surface of a color picture tube is formed by a photographic method. Specifically, a photosensitive binder, such as an aqueous solution of polyvinyl alcohol and dichromium 1lIj! ! A solution made of a photosensitive solution is applied to the inner surface of a glass panel and dried to form a film.

Then, through the shadow mask as a color selection electrode,
The film is exposed to light using a predetermined exposure device to form a latent image. Then, by developing this film,
A resist stripe or a phosphor stripe of a predetermined size is formed at a desired position.

As can be seen from the above description, forming the fluorescent surface includes the step of applying a film-forming solution to the inner surface of the glass panel forming the cathode ray tube.

In addition to the above-mentioned method, there is also a method in which a graphite solution of a black matrix is applied to the inner surface of a glass panel to simply form a film. Alternatively, emulsion filming, which is performed after forming phosphor stripes, involves a number of steps in which film-forming solutions are applied to the inner surface of the glass panel. In all the above coating steps, so-called spin coating is employed. That is, the glass panel is rotated at high speed to remove excess solution from the outside of the glass panel using centrifugal force, and the thickness of the film on the inner surface of the glass panel is adjusted.

FIG. 1 is a schematic diagram of the apparatus used for the spin coating described above. Glass panel 1 forming a cathode ray tube
is firmly held by carrier 2. This carrier 2 is rotationally driven by a motor 3, thereby rotating the glass panel 1 around a rotation axis 4. Usually, an automatic machine for forming a fluorescent surface of a color cathode ray tube has a carrier 2 for holding the glass panel 1 fixedly arranged in a line in the form of a loop. Then, the glass panel 1 is sequentially moved at a predetermined cycle time to finally form a fluorescent surface on the inner surface of the glass panel 1. Figure 1 shows
The glass panel 1 is shown in the swing-off position.

That is, when the glass panel 1 with the phosphor slurry 6 injected into its inner surface enters the shake-off position, the collection container 7, which was in the standby position shown by the imaginary line, is lowered to the position shown by the solid line. The glass panel 1 is driven to rotate at high speed by a motor 3. Due to the centrifugal force generated by this rotation, the excess phosphor slurry 6 on the inner surface of the glass panel 1 is thrown off to the outside of the glass panel 1 and collected in the collection container 7. At the same time, the thickness of the slurry film 6 formed on the inner surface of the glass panel 1 also changes. The longer the swing-off time is, the smaller the film thickness will be, and the faster the rotational speed of the drive motor 3 is, the smaller the film thickness will be. This film thickness is an important control factor that determines the light output, uniformity of light emission, etc. in the finished tube. Therefore, motor 3 usually has 1 liter.
IIIIliilF8 is connected and this control
11 device 8 allows the rotation of the motor 3 to be set arbitrarily.

Factors that control the film thickness include, in addition to the above-mentioned swing-off time and rotation speed, the inclination angle θ between the rotational axis 4 and the vertical axis 5 of the glass panel 1, the viscosity of the solution to form the film, and the coating process. There are various factors such as timing and method, concentration of glass panels, etc.

Note that film thickness control is an important item in any of the other film formations mentioned above, although the details are different.

When glass panels having fluorescent surfaces of the same size are processed on the same line, once the various conditions described above are set, there is little need to change them thereafter. In the past, it was not very necessary to manufacture products with different sizes of fluorescent surfaces on the same automated line, but with the recent diversification of products, products with different sizes of fluorescent surfaces have been manufactured on the same line. It has become a matter of course that glass panels be mixed on the same line. Furthermore, the number of composites is as many as 4 pipe types. In such a case, it is very difficult to set suitable conditions for each size of glass panel and form a film having an appropriate thickness for each glass panel.

Therefore, this invention, when glass panels with different sizes of fluorescent surfaces are mixed on the same production line, easily sets the optimal conditions for each size, and thereby The purpose is to provide a method that allows accurate m-thickness control.

[Means for Solving Problem E] This invention applies a film-forming solution to the inner surface of a glass panel forming a cathode ray tube, and then rotates the glass panel at high speed to remove excess solution by centrifugal force. A method for forming a fluorescent surface of a cathode ray tube, which captures the outside of a glass panel and adjusts the film thickness on the inner surface of the glass panel, and is characterized by the following features. That is, when glass panels with different sizes of fluorescent surfaces are mixed on the same production line, the values should be set in proportion to each other.

[Function] Methods for equalizing the film thickness or quality characteristics of different metals include controlling the viscosity of solutions, controlling the timing and method of coating, controlling the temperature of the glass panel, controlling the shake-off time after coating, There are various methods, such as controlling the swing-off rotation speed and controlling the tilt angle of the glass panel. The inventor of this application is
A large number of experimental results and actual results were compared and examined. As a result, it has been found that among the various control methods described above, controlling the rotation speed of the glass panel is the most effective and easiest. It has also been found that if the film thickness is controlled by Ill IN at this rotational speed, a film of excellent quality can be obtained. Control of the rotational speed of the glass panel acts as an IN control of the magnitude of centrifugal force.

Furthermore, the inventor of the present application investigated the optimum rotation speed for obtaining a coating of appropriate thickness for glass panels of various sizes, and found that the following relationship was obtained. That is, when the size of the glass panel is D, it is possible to obtain a film with a thickness corresponding to that of each size of glass panel.

[Embodiment of the invention] Sizes 20″, 21″, 25″,
Resist solution for forming a black matrix for 4 types of 28" pipes (polyvinyl alcohol solution and layer chromium I)
II salt] was applied to form a film. The viscosity of the solution was 5°5 cp. After pouring the solution onto the inner surface of the glass panel, the following rotation speed was set for each size of glass panel. In this case, the size of each glass panel was set as D, and the following settings were made based on the value for the conventional size 20'', that is, the value at i4Qrpm for 18 seconds.

(1) Pipe type: 20” size (W standard) Number of rotations for resist coating: 140r Number of rotations for shaking off Dll solution: 1aorps (2) Pipe type: 2
1″ Number of revolutions for applying size resist: 136 rpm Number of revolutions for shaking off solution: 156 rpi (3) Pipe type: 25″
Number of revolutions for size resist application: 125 rpm Number of revolutions for removing solution: 143 rps (4) Tube [:28"
Number of rotations for shaking off the size solution: 133rl) 1 Actually,
Sizes 21″ and 25″ with the above settings.

When a 28" version was produced, there were no particular problems and the quality was excellent.

In addition, an automatic fluorescent surface coating machine with an index time of 24 seconds is used to coat sizes 20'', 21'', 25n, and 2.
Edge wall light slurry films were formed on four types of Bn tubes. The solution used was a system in which a green-emitting phosphor slurry was dispersed in a system containing polyvinyl alcohol solution and dichromate as photosensitive components, and its viscosity was 2.
5 cp, specific gravity was 1°290. After injecting this slurry liquid into the inner surface of the glass panel, the conventional size 20''
, i.e., 160rl) ■, and the value for 15 seconds is the standard, and the size 21 is set as the above setting value.
.

The processing was performed by setting rotational speeds for 25'' and 28''. As a result, the coating amount distribution (ma/
cm') and the luminous uniformity of the completed tube were particularly problematic and had reached disappointing values. That is, the coating amount of the phosphor formed under the rotational speed set as described above was 3°1±0, 15mQ/c.
It was within m'.

Needless to say, the rotational speed of the glass panels of each size is controlled by controlling the rotational speed of the motor 3 based on an electrical command issued from the control device 8 (see FIG. 1).

Further, the motor 3 used for taking a shot of the solution may be a motor fixed in each step, or may be a motor directly attached to each carrier 2. Furthermore, the motor type may be a direct current type,
Alternatively, an AC inverter type may be used.

The inclination angle θ of the glass panel 1 can be arbitrarily set depending on the configuration of the line, the characteristics of the solutions to be applied, the handling method, etc. For example, the inclination angle θ may be 155°, 80 to 85° that is nearly vertical, or 30 to 400°.

In the above embodiments, the application of the resist solution and the application of the phosphor slurry liquid have been explained, but the setting of the rotation speed for controlling the thickness according to the present invention is not limited to the application of the graphite solution for the black matrix or the application of the phosphor slurry liquid.
Needless to say, the present invention can also be applied to the application of a filming solution after forming a colored fluorescent surface.

[Effects of the Invention] As described above, in this invention, when glass panels with fluorescent surfaces of different sizes are mixed on the same production line, the size of the glass panel is set to D, and such setting is very easy. Moreover, this setting ensures accurate film thickness control. The obtained film has good quality, and the yield of the process can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus used for so-called spin coating. In the figure, 1 is a glass panel, 2 is a carrier, 3 is a motor, 4 is a rotation axis, 5 is a vertical axis, 6 is a fluorescent slurry, 7 is a collection container, and 8 is a control device.

Claims (1)

[Claims] After applying film-forming solutions to the inner surface of a glass panel forming a cathode ray tube, the glass panel is rotated at high speed to shake off excess solution to the outside of the glass panel using centrifugal force. In the cathode ray tube fluorescent surface formation method that adjusts the film thickness on the inner surface of the panel, when glass panels with different sizes of fluorescent surfaces are mixed on the same production line, each size is The rotation speed for the glass panel is
A method for forming a fluorescent surface of a cathode ray tube, characterized by setting the fluorescent surface in proportion to the value of √[1/(D/2)].