JPS60258830A - Formation of phosphor film - Google Patents

Abstract

PURPOSE:To maintain the panel temperature constant by spraying water of such temperature as corresponding with the panel temperature onto the inner face of panel thereby eliminating the defects such as excessive or insufficient drying after application of phoshor material. CONSTITUTION:Upon detection of high panel A temperature through a sensor D, the temperature of water to be ejected through a nozzle C1 is lowered while it is increased upon detection of low panel temperature. Panel mounting device B is rotated to feed the hot water entirely onto the inner face of panel A. Said operation is performed continuously upon arriving of panel A to the positions of nozzle C1, C2 to maintain the temperature of panel A at predetermined level. Then residual water is removed from the panel A to apply phosphor material thus to complete the predetermined process, and when drying thereafter, excessive and insufficient drying can be prevented to achieve constant drying condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a method for forming a fluorescent film for a color picture tube.

(4) The phosphor film of the conventional color picture tube has various colors, such as green, on the inner surface of the panel.
Each blue and red phosphor film pattern is painted in a predetermined positional relationship, and a color selection electrode such as a shadow mask or aperture grill is attached at a predetermined distance from this phosphor film. As a result, the electron beams corresponding to green, back, and red are respectively positioned on the phosphor film patterns of the corresponding colors on the phosphor film.

The general method for forming such a phosphor film pattern is to clean the inner surface of the panel and then apply a base coat, commonly known as an undercoat, containing polyvinyl alcohol as the main component to provide adhesive strength between the panel and the phosphor. After applying the solution, drying is performed, and then polyvinyl alcohol, a dichromate salt (for example, ammonium monodichromate), which imparts photosensitivity to this and causes a crosslinking reaction upon exposure, and green phosphor powder are applied. Apply the phosphor slurry mixed with the phosphor and dry it to form a uniform film. This film is exposed through a shadow mask,
A cross-linking reaction is caused at the position corresponding to the green electron beam,
A green fluorescent film pattern is created at the exposed position by development. By repeating such operations, blue and red fluorescent film patterns are sequentially arranged and created in a predetermined arrangement.

When forming a fluorescent film by the above method, it is important to dry uniformly in the drying step after coating the fluorescent slurry. If the drying is too strong, the development process in the next step will not be successful, and the phosphor elements forming the phosphor pattern will not be separated, resulting in the so-called fogging phenomenon.On the other hand, if the drying is too weak, the phosphor There is a problem that the element may fall and a part of the fluorescent film pattern may be missing. In order to avoid such problems, it goes without saying that it is necessary to keep the drying period constant after coating the phosphor slurry, and also to keep the panel temperature constant before coating.

Conventionally, an infrared heater has been used as a heat source for drying before and after coating, but with such an infrared heater, it is impossible to make the panel surface uniform, and it is inevitable that the central part This results in uneven drying of the surrounding area. Furthermore, there are panels that are attached to a fluorescent film coating machine that have different temperatures.

゛For example, when forming a fluorescent film on a panel on which an IJx film (black matrix film) has been formed in a step before the fluorescent film forming process, the panel temperature immediately after the black matrix film is formed is about 30°C. However, depending on the flow of the process, differences in the input time up to the fluorescent film forming process may cause a difference in the panel temperature. In such a panel, it is impossible to uniformly dry the coating after coating, causing the above-mentioned problems in the process.

(J OBJECT OF THE INVENTION The present invention provides a method for eliminating such drawbacks such as over-drying and insufficient drying and keeping the temperature of a panel constant.

(4) Embodiment of the Invention As shown in FIG. 1, a panel A having a black matrix film formed on the inner surface of the panel is attached to a panel mounting device B. Thereafter, the temperature of panel A shown in FIG. 2 is detected by sensor D. When the panel A attached to the panel mounting device B arrives at the position where the nozzle Ct is located, as shown in FIG. 3, pure water H corresponding to the temperature detected above is ejected from the nozzle C1. , spray onto the inner surface of panel A.

When sensor D detects that the temperature of panel A is high, the hot water ejected from nozzle C1 is set at a low temperature, and when it is detected as low, the hot water is set at a high temperature. Also, rotate panel B so that the hot water spreads over the entire inner surface of panel A.

This is done to maintain a uniform temperature throughout the panel.

By continuously performing this operation when the panel A arrives at the position of the nozzles CI, C2, . . . , it is possible to bring the temperature of the L panel B to a predetermined temperature. Moreover, the predetermined temperature can be maintained by using as much water as possible. Remove any moisture remaining on the panel that has reached this predetermined temperature,
If the phosphor is then applied, the prescribed process is completed, and the phosphor is dried after being applied, over-drying or under-drying can be prevented, and it is possible to form a constant dry state.
- It goes without saying that it is possible to improve the quality of the fluorescent film.

An example using a 1411-inch color picture tube with panel temperatures of 26'G and 22°C is shown below.

Nozzles CI and C2 for panels detected as 26°C.
Pure water at a temperature of 25° C. is fired for 10 seconds each. Also, for panels detected as 22°C, nozzle CI
, C2 and multiple temperatures of 45° C. are fired for 10 seconds each.

Here, the nozzles are expressed as CI and C2, but the nozzle CI
, C2 is connected to two pure water pipes, and as shown in Figure 3, the El pipe is 25"C, and the E2 pipe is 4"C.
Pure water at a temperature of 5°C is sent, and a sensor opens and closes a solenoid valve to send out each type of pure water.

Examples have been shown above, but for panels at other temperatures, pure water at 25°C and 45°C is emitted for a time corresponding to the panel temperature to provide a rinsing effect, and then the usual method can be used. By using an infrared drying method, it is possible to bring the panel temperature to a predetermined temperature before applying the phosphor slurry. In Example 6, CI and C2L are not used as nozzles, but it goes without saying that increasing the number of nozzles will result in a more uniform panel temperature.

(5) Effects of the Invention As explained above, the present invention lowers the panel temperature before applying the phosphor slurry to a predetermined temperature by spraying pure water at a temperature corresponding to the panel temperature onto the inner surface of the panel. It is possible to maintain the maximum variation within 1℃, eliminate over-drying and insufficient drying after coating the phosphor, and reduce uneven drying between the center and the periphery, resulting in high-quality phosphor. By forming a film, it is possible to stabilize the process, and the effect of improving quality and improving yield is significant.

[Brief explanation of drawings]

Figure 1 is a diagram of the panel being attached to the panel mounting device and pure water being ejected from the nozzle. Figure 2 is a diagram of the panel temperature being detected by a sensor, viewed from the top. Figure 3 is a top view showing how pure water corresponding to the detected temperature is being ejected from the nozzle. A...Panel, B...Panel mounting device, CI, C2...-/Xle, H...Pure water, D... Sensor, El...Piping (3
5℃), E2...Piping (45℃).

Claims (1)

[Claims] A photosensitive phosphor slurry is applied to the inner surface of the panel. It is dried, exposed to light, and then developed.
In the process of forming green, blue, and red phosphor element patterns, rinsing is performed with purified water whose temperature is adjusted to offset the panel temperature according to the panel temperature before each color phosphor slurry is applied. A method for forming a fluorescent film, which comprises: bringing the panel temperature to a certain level required for forming a fluorescent film pattern, and then applying a fluorescent slurry.