JPH02106849A - Method of forming fluorescent surface of color picture tube - Google Patents

Abstract

PURPOSE:To enable the formation of an uniform and excellent photoresist film by injecting a photoresist while rotating a glass panel, then stopping the rotation to suck and remove the photoresist stayed on the inner surface of the glass panel, and again rotating the glass panel. CONSTITUTION:A glass panel 1 is held with the inner surface of the glass panel 1 upward in such a manner that the angle between the center axis 1 of the glass panel 1 as a rotating axis and plumb line is 10-25 deg., and rotated at a low speed. A fixed amount of a photoresist solution is applied to the center part of the glass panel 1 by a spray nozzle 2. When the rotation of the glass panel 1 is stopped in the point where an optional point of the corner part of the rectangular glass panel 1 is situated in the lowest point O' over the center point O of the glass panel 1, the excessive resist is stayed in said corner part. The excessive resist is sucked and removed from the inner surface of the glass panel 1 by a suction nozzle 3, and the glass panel 1 is again rotated at a high speed. Hence, an uniform photoresist film having no unevenness can be formed on the glass panel 1 inner surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a phosphor screen of a color picture tube, and more particularly to a method of applying a photoresist to the inner surface of a glass panel of a color picture tube.

[Conventional technology]

The phosphor screen of a color picture tube has a structure in which the gaps between phosphor dots placed on the inner surface of the glass panel are filled with a non-luminescent light-absorbing material, such as carbon black, to improve the brightness and contrast of the screen. There is a so-called black matrix type that has a screen. An example of the manufacturing process for the black matrix fluorescent screen of this color picture tube is as follows.

(a) Apply photoresist to the inner surface of the glass panel and dry.

(b) Attach a shadow mask and expose the portions of the phosphor corresponding to the green, blue, and red light emitting portions to ultraviolet light.

(C) Remove the shadow mask and develop to form dots of photocured photoresist.

(d) A suspension of a non-luminescent light-absorbing substance, such as colloidal black carbon, is applied to the inner surface of the glass panel so as to overlap the dots of the non-photocurable photoresist, and dried.

(e) The photocured resist to which the non-luminescent light-absorbing substance has been adhered is destroyed and removed by a stripping solution to form matrix holes made of the non-luminescent light-absorbing substance.

(f) Three colored phosphor slurries of green, blue and red are sequentially applied, dried, exposed and developed to obtain phosphor dots in predetermined matrix holes.

(g) After that, a metal thin film is formed by vapor deposition.

In the above-mentioned manufacturing method, the step of applying resist to the inner surface of the glass panel is particularly important in forming a uniform photoresist coating. In other words, if there are uneven parts in the photoresist coating, or if there are uneven local film thickness due to bubbles in the photoresist that occur during coating, the sensitivity of the photoresist will change, causing the size of the photocured dots due to exposure to light. As a result, the size of the black matrix dots formed from the light-absorbing material becomes locally abnormal, which causes a defect in the appearance of the phosphor screen. Furthermore, when the color picture tube is operated, local brightness and color unevenness occurs on the fluorescent screen, which poses a quality problem. Therefore, it is important to uniformly apply the photoresist to the entire inner surface of the glass panel.

[Problem to be solved by the invention]

A conventional photoresist coating method will be explained with reference to FIGS. 3 and 4. The first method, as shown in FIG. The photoresist solution 10 is applied while being poured from the coating nozzle 9 placed opposite to the photoresist solution 10. At this time, the excess photoresist solution 10' is collected in the recovery tank 11.Next, the photoresist solution 10 is discontinued from being poured.
A photoresist film is formed on the inner surface of the glass panel 8 by rotating the glass panel 8 at high speed while keeping the angle at 90 degrees with the central axis g of the glass panel 8 as the rotation axis. According to this method, a large amount of photoresist is required to completely cover the inner surface of the glass panel with photoresist, and when it is applied, traces of photoresist and resist bubbles may be left on the inner surface of the glass panel. This problem easily appears, causing local non-uniformity in the photoresist film, resulting in a failure to form a uniform photoresist film.

In the second coating method, first, as shown in FIG. The photoresist liquid 14 is injected into the glass panel 12. Next, as shown in FIG. 4(b), the angle between the central axis ρ of the glass panel 12 and the vertical line is gradually tilted counterclockwise until it reaches 20 degrees. , spread the photoresist around the periphery of the glass panel 12. Next, as shown in FIG. Photoresist on glass panel 1
2. 6. Next, high-speed rotation is performed on the glass panel 12.
to form a photoresist film. In this method, when spreading the photoresist on the inner surface of the glass panel 12, the central axis of the glass panel 12 is gradually adjusted by rotating it. When flowing around the periphery of the glass panel 12, it collides with the side wall 15 of the glass panel 12 and generates bubbles, which impairs the uniformity of the photoresist film as described above.Furthermore, the rotational speed and tilting speed of the glass panel 12 The disadvantage is that it is not easy to make adjustments.

However, when the excess resist is discharged from the glass panel 12, traces of discharge of the photoresist appear when there is a large amount of excess resist, and the photoresist film becomes uneven.

[Means to solve the problem]

When applying photoresist to form a phosphor screen on the inner surface of a glass panel of a color picture tube, the present invention turns the inner surface of the glass panel upward and maintains the angle between the central axis of the glass panel and the vertical line at a predetermined angle. The glass panel is then rotated while injecting photoresist, the rotation is stopped and the photoresist that has accumulated on the inner surface of the glass panel is suctioned away, and the glass panel is rotated again. shall be.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view for explaining a first embodiment of the present invention. The center axis of the glass panel 1 (the axis of rotation is the angle between the well-washed glass panel 1 and the vertical line is 1).
The glass panel 1 is held with the inner surface facing upward at an angle of 5 degrees and rotated at a low speed of 10 to 2 ORPM. Then add a certain amount of a photoresist solution, such as a solution consisting of polyvinyl alcohol and dichromate (15 in the case of type 20).
0m, R) to the center of the glass panel 1 using the nozzle 2.
Apply more. Since the glass panel 1 is angled and rotated, the photoresist extends from the center of the panel to the periphery, covering the entire inner surface of the panel. Next, any one point in the corner of the rectangular glass panel 1 is the glass panel 1.
When the rotation of the glass panel 1 is stopped at a point located at the lowest point 0' from the center point O of the glass panel 1, the excess photoresist remains at a part of the corner. Next, the suction nozzle 3 sucks and discharges the excess resist from the inner surface of the glass panel 1. Thereafter, the glass panel 1 is again rotated at a high speed of 150 to 200 RPM to form a --like photoresist film on the inner surface of the glass panel. The suction nozzle 3 is connected to a diaphragm type pump or an aspirator (not shown), and the photoresist sucked in is filtered, recovered, and reused. At this time, the amount of suction must be performed within a predetermined time, and here, the amount of suction was set at 10 J7/min.

When the angle between the central axis of the glass panel 1 and the vertical line exceeds 30 degrees in the counterclockwise direction, the speed at which the photoresist flows along the inner surface of the glass panel increases and it hits the side wall 4 of the glass panel 1. As a result of experiments, it was found that the optimum angle is between 25 degrees and 10 degrees counterclockwise because bubbles are likely to occur and the photoresist will not be applied to the periphery of the glass panel 1 if the angle is less than 10 degrees. did.

Here, an example of 15 degrees is shown. According to this method, when forming a photoresist film on the inner surface of the glass panel 1, it is possible to apply the photoresist solution without generating bubbles on the inner surface of the glass panel, and when draining the photoresist solution from the inner surface of the glass panel, excess resist can be removed. No accumulation occurred on the inner surface of the panel, and it was possible to form a uniform photoresist film free from unevenness due to accumulation.

FIG. 2 is a longitudinal sectional view for explaining a second embodiment of the present invention. With the inner surface of the glass panel 5 facing upward, and with the central axis ρ as the rotation axis and the angle between it and the vertical line maintained at 20 degrees, apply photoresist liquid using the nozzle 6 in the same manner as in the first embodiment.
After coating the inner surface of the panel, the angle between the central axis J of the glass panel 5 and the vertical line was changed to 90 degrees.
Provides high speed rotation of 30-150 RPM. In this case, the resist film on the inner surface of the glass panel is subjected to force in the direction of gravity, so it can be easily adjusted to the desired thickness at a lower rotation speed than in the first embodiment. This is done through a drip-proof shutter (not shown) to prevent the resist from scattering around. At this time, the photoresist that has been scattered due to high-speed rotation returns from the drip-proof plate again and is deposited on the inner surface of the glass panel 5. It is better to keep the rotational speed as low as possible in order to prevent the glass from bouncing, but according to this method, it is possible to lower the rotational speed than in the first embodiment. It was possible to form a photoresist film without any

〔Effect of the invention〕

As described above, according to the present invention, a uniform and good photoresist film can be formed on the inner surface of the glass panel of a color picture tube, and a black matrix phosphor screen without defects such as bubbles can be obtained. It is possible to provide a good image without color unevenness or brightness unevenness during tube operation.

[Brief explanation of drawings]

Fig. 1 is a sectional view for explaining the first embodiment of the present invention, Fig. 2 is a sectional view for explaining the second embodiment of the invention, and Fig. 3 is a sectional view for explaining the conventional example. FIGS. 4(a) to 4(c) are sectional views for explaining other conventional examples. 1.5, 8.12...Glass panel, 2,69.13
...Application nozzle, 3,7...Suction nozzle, 4.15
...Side wall part.

Claims (1)

[Claims] When forming a phosphor screen on the inner surface of the glass panel of a color picture tube, turn the inner surface of the glass panel upward and hold the angle between the central axis of the glass panel and the vertical line at 10 to 25 degrees counterclockwise. A collar characterized by comprising the steps of rotating the panel and injecting photoresist, then stopping the rotation and suctioning off the photoresist that has remained on the inner surface of the glass panel, and rotating the glass panel again. Method for forming a phosphor screen in a picture tube.