JPH0818851B2 - Color picture tube panel cleaning method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for cleaning a panel for a color picture tube.

(Prior art) In recent years, the screens of color picture tubes have become finer and finer, and the finest screens are represented by medium- and high-definition display tubes. More than 5 million (14 inch 0.20mm pitch circular holes) Mask type) consists of picture elements.

Therefore, in the work of forming a fluorescent screen corresponding to the innumerable picture elements, various difficulties are involved in obtaining a screen without defects.

As shown in FIG. 2, the conventional process for forming a fluorescent screen such as a black matrix type fluorescent screen or a black stripe type fluorescent screen is as follows. Wash for 15 seconds,
Immediately after that, in the pickling step 11, hydrofluoric acid (HF concentration: 10 to 18%), nitric acid (HNO ₃ concentration: 5 to 10%), or a mixture of these or the like is used for pickling for 30 seconds to 1 minute, and then again in the washing step 12
Wash with water for about 30 to 1 minute. And resist coating process
After applying the resist in 13, the film is sent to the exposure and printing process of the next process through the drying process 14.

(Problems to be solved by the invention) However, in the conventional manufacturing method, when the panel and the mask are combined and passed through a furnace at about 450 ° C. to be thermally stable,
Dust adhering to the mask and dust adhering to the inner wall of the panel, as well as heavy metals such as iron powder in the furnace, oil residue, and dust such as vinyl chloride cling strongly to the inner surface of the panel due to high heat, Since these deposits are not completely removed in the water washing step, there is a problem that the deposits cause uneven etching during the pickling process.

For example, as shown in FIG. 3 (a), when the dust 2 is firmly adhered to the surface of the panel 1 and the etching process is performed in the pickling step, the dust adheres as shown in FIG. 3 (b). Since the progress of the etching due to the hydrofluoric acid is slower in the dust-free portion, that is, in the normal portion, the dust deposit remains as the convex portion 3 and the smoothness of the inner surface of the panel 1 is impaired. Therefore, when the resist film having a thickness of 0.5 μm or less is formed after the cleaning, the coating cannot be made uniform, and fine defects eventually occur in the resist film.

When the size of dust that causes the resist film defect was examined, it was found that most of them were about 20 μm or more.

As an example, in the 14-inch 0.31 mm pitch black matrix phosphor screen, the number of defects per panel was 2-3. Usually, this defect is repaired by a person who corrects the inspection process, but since such a defect is minute, inspection work is difficult.

An attempt has been made to completely remove the deposits on the inner surface of the panel by repeating washing with water, pickling, washing with water, pickling and washing with water in the above steps, but this has not been completely solved.

In addition, after the pickling process, brushing was performed to remove dust, but since it was after pickling, the part with dust remained in a convex shape without being pickled, and the surface of the panel The flatness was not improved.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for cleaning a panel for a color picture tube, by which dust adhering to the inner surface of the panel is completely removed and the flatness of the panel plane is improved. .

[Structure of the Invention] (Means for Solving the Problems) In the method for cleaning a panel for a color picture tube of the present invention, a heat treatment is carried out in a high temperature environment by combining a panel having no fluorescent screen and a shadow mask. The first step of washing the inner surface of the heat-treated panel with a soft material while brushing the inner surface of the heat-treated panel with a soft material so as to remove the deposits on the inner surface of the panel without damaging the panel The present invention is characterized by including a water washing step, a pickling step of subjecting the washed panel to a pickling treatment, and a second water washing step of washing the pickled panel with water.

(Operation) The present invention can completely remove metal oxide powder and other dust adhering to the inner surface of the panel by performing a physical cleaning process.

(Example) Hereinafter, one example of the method of the present invention will be described with reference to FIG.

The panel cleaning method for color picture tubes of this example is roughly divided into a physical cleaning method and a chemical cleaning method.The panel selected in the black matrix or black stripe forming step is first subjected to nylon brushing in the detergent brushing step 20 as the physical cleaning method. Physically brush for about 10 to 15 seconds using L-92 (trade name: Prolonic Surfactant 0.2% solution) with a brush or gauze, then wash with water for about 15 seconds in washing step 21 and then acid. In the washing step 22, spraying with a hydrofluoric acid (10-18%) solution at a pressure of 1-1.5 kg / cm ² for 15-30 seconds.

Then, after high-pressure water washing with a pressure of 5 kg / cm ² is performed in the final pure water washing step 23, a resist is applied in a resist applying step 24, and a drying step 25 is carried out, followed by sending to the next exposure / baking step.
When the panel was actually processed by such a method for cleaning a panel for a color picture tube, the number of defects (14 inch 0.31 mm pitch) per panel became 0. Furthermore, when 100 sheets of this type of panel were washed, 80 or more unmodified panels could be obtained.

As described above, according to the panel cleaning method for a color picture tube of the present invention, the dust adhering to the inner surface of the panel can be completely removed, so that the inner surface of the panel becomes smooth and the panel is uncorrected. Can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the method of the present invention, FIG. 2 is a diagram showing a conventional method, and FIG. 3 is a diagram showing the influence of deposits in the pickling step in the conventional method. 1 ... Panel 2 ... Adhesion 3 ... Convex 20 ... Detergent brushing process 21 ... Water washing process 22 ... Pickling process 23 ... Pure water washing process 24 ... Resist coating process 25 ... Drying process

Claims (1)

[Claims] 1. A heat treatment step in which a panel without a fluorescent screen and a shadow mask are combined to perform heat treatment in a high temperature environment, and the inner surface of the heat treated panel is brushed with a soft material while supplying a cleaning liquid. A cleaning step of removing the deposits on the inner surface of the panel without damaging the panel, a first rinsing step of rinsing the brushed panel with water, a pickling step of pickling the washed panel, and A method for cleaning a panel for a color picture tube, which comprises a second washing step of washing the pickled panel with water.