JPH07120506B2 - Method for forming fluorescent screen of color cathode ray tube - Google Patents

Description

The present invention relates to a method for forming a fluorescent film for a color cathode ray tube.

[Conventional technology]

Conventionally, a fluorescent screen forming method of a color cathode ray tube forms fine dots of green, blue, and red phosphors at locations determined by a black film made of graphite called a black matrix film. Generally, a phosphor suspension (phosphor slurry) prepared by mixing a phosphor of the first color with a solution containing a photosensitive polymerizing agent such as polyvinyl alcohol or ammonium dichromate is applied to the inner surface of a panel having a black matrix film formed thereon. Then, the panel coated with the phosphor slurry is rotated at a high speed to spread it evenly on the inner surface of the panel. Next, while rotating the panel at a low speed, the panel is dried by an infrared heater or the like, and then exposed through a shadow mask by an exposure device using an ultra-high pressure mercury lamp, and then hot water is sprayed for development to form fine dots of the first color. Let it form. Hereinafter, the same process is repeated to form minute dots of the remaining two colors. After forming the three-color dots, an organic coating liquid (filming liquid) is applied for forming an organic coating on the three-color dots of green, blue, and red as a pretreatment for forming the Al vapor deposition film.

[Problems to be Solved by the Invention]

The conventional filming liquid application process is the third among the three color dots.
After the development process of the dots (usually red) formed in the color is completed, the process shown in FIG. 4 is performed. The inner surface of the panel is dried by the drying process, and the panel temperature is raised to about 40 ° C. which is the temperature required for curing the acrylic emulsion which is the main component of the filming liquid. Next, as shown in FIG. 3, the panel 1 to which the filming liquid is applied is fixed and rotated by the panel fixing and rotating device 10 with the panel clamp 11 at a certain angle with the central axis of the panel and the vertical direction. is doing. The filming liquid is applied to the entire inner surface of the panel 1 by the injection nozzle 4 and allowed to stay, and then the filming liquid is discharged. Then, it was dried by an infrared heater to form a film. Since the viscosity of the filming liquid is about 1.0 _CPS, which is about 1/40 of that of the phosphor slurry, the filming liquid easily flows, and to apply it to the entire inner surface of the panel, the angle between the panel center axis and the vertical direction should be adjusted while applying. A method of changing the length or increasing the residence time of the filming liquid on the inner surface of the panel has been adopted. However, when the coating amount of the filming liquid increases with the increase in the size of the panel and the flat face of the panel in recent years, the inner surface of the panel fires due to the contact between the inner surface of the panel and the filming liquid, and the foaming unevenness occurs, and the residence time When the length was increased, the inner surface of the panel was already raised to near the emulsion curing temperature, so that partial curing of the emulsion occurred, causing unevenness in the film and reduction in brightness, and the quality of the fluorescent screen was significantly reduced.

It is an object of the present invention to provide a method for forming a fluorescent screen of a color cathode ray tube which solves the above problems.

[Means for Solving the Problems]

In order to achieve the above object, the method for forming a phosphor screen of a color cathode ray tube according to the present invention applies a phosphor suspension to the inner surface of the panel while rotating the panel of the color cathode ray tube, performs each step of exposure and development, and In the organic film forming step performed after the formation of the three-color phosphor screen at the time of forming the phosphor film of the color cathode-ray tube for forming the three-color, blue and red phosphor screens, the inner surface of the panel is wetted in advance, and then the organic film forming liquid is added. It is applied without being retained on the inner surface of the panel.

〔Example〕

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

(Embodiment 1) FIG. 1 is a side view showing an embodiment of the present invention.

In the figure, the panel 1 is fixed to the panel fixing / rotating device 10 by the panel clamp 11, and the processes shown in FIG. 2 are sequentially performed while rotating the panel 1 about the panel center axis. During the execution of each process, the vertical direction and the central axis direction of the panel always form an acute angle.

While rotating the panel in the drying process, on the inner surface of the panel 1 dried and heated by an infrared heater or a warm air blower,
Spray nozzle 2 connected to a pure water tank placed at a high place and a solenoid valve (both not shown) that opens and closes in conjunction with the process
Warm pure water from above to wet.

Similar to the wetting process, the panel 1 that rotates the filming liquid from the coating nozzle 3 that is installed in the filming liquid tank placed at a high place and the solenoid valve (both not shown) that opens and closes in conjunction with the process Apply to the inner surface of. The film is then spread over the entire inner surface of the panel by a shake-off process to form a uniform film. The filming film is dried and cured in the drying process.

The organic coating formed by such a method does not partially cure the acrylic emulsion as the main component, and does not cause unevenness due to bubbles during coating. Therefore, the metal reflection film formed next is uniform, and the quality of the fluorescent screen of the color CRT can be improved.

(Example 2) As Example 2, a 0.5 to 1% aqueous solution of a nonionic surfactant from the spray nozzle 2 in the wet process (trade name: Tw
Alternatively, a dilute aqueous solution in which 1 to 2 wt% of the organic emulsion which is the main component of the filming solution is dissolved is applied in the same manner as in Example 1 to form an organic film. According to this embodiment, there is an advantage that the brightness of the color CRT can be improved by 2 to 3% as compared with the case of being wet with water.

〔The invention's effect〕

As described above, the present invention wets the inner surface of the panel immediately before applying the filming liquid, and then applies the filming liquid without stagnation on the inner surface of the panel.
It is possible to prevent the partial curing of the organic emulsion which is the main component of the filming liquid and the occurrence of bubble unevenness, form a uniform organic coating on the phosphor dots, and significantly improve the quality of the phosphor screen. Has a great effect on a large-sized panel or a so-called flat face panel having a large inner surface curvature.

[Brief description of drawings]

FIG. 1 is a side view showing a wetting and coating process of a filming process of the present invention, FIG. 2 is a process block diagram showing a filming process of the present invention, and FIG. 3 is a coating process of a conventional filming process. FIG. 4 is a side view and FIG. 4 is a process block diagram showing a conventional filming process. 1 ... Panel, 2 ... Spray nozzle 3 ... Coating nozzle, 4 ... Injection nozzle 10 ... Panel fixed rotation device, 11 ... Panel clamp

Claims (1)

[Claims] 1. A color for forming a phosphor screen of three colors of green, blue and red by applying a phosphor suspension to the inner surface of the panel while rotating the panel of a color cathode ray tube and performing each step of exposure and development. In the organic film forming step performed after the formation of the three-color phosphor screen when forming the fluorescent film of the cathode ray tube, the panel inner surface is wetted in advance, and then the organic film forming liquid is applied without staying on the panel inner surface. Method for forming fluorescent screen of cathode ray tube.