JPH05159701A - Method for applying conductive material to neck of cathode ray tube - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for applying a conductive material to a neck portion of a cathode ray tube body capable of obtaining a stable and uniform conductive material film thickness. In a method of spin-coating a conductive material onto a predetermined width region of a tube neck portion 2 of a funnel tube using a coating means 4 capable of impregnating a melt, a predetermined amount of the melt of the conductive material is applied to the coating means 4. After the impregnation, a step of sequentially applying the conductive material from the upper end to the lower end of the predetermined width region, and further continuously applying the conductive material from the lower end to a predetermined height, and at the time of applying the predetermined height, the applying means 4 The method further comprises the step of supplying a predetermined amount of the conductive material to the coating means while continuing the rotation of, and then applying the conductive material to the upper end of the predetermined width region while supplying the conductive material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a conductive material to the neck portion of a cathode ray tube body, which allows a thick film to be applied uniformly.

[0002]

2. Description of the Related Art A cathode ray tube (CRT) used as a cathode ray tube of a television is composed of a panel on the image screen side and a funnel funnel in which an electron gun is arranged. If a discharge sometimes occurs and a large current flows in the CRT during operation, it causes inconvenience such as damage to the circuit components of the set. In order to avoid this inconvenience, it is necessary to suppress the discharge current to, for example, 200 A or less. As a method of suppressing this discharge current, there is known a method in which a resistor made of a conductive material film is provided on a neck portion of a funnel tube.

As a method of forming a conductive material film serving as a resistor on the funnel neck tube, a brush or sponge or the like is conventionally impregnated with a conductive material paint such as carbon (graphite), and the inner wall of the funnel tube neck has the above-mentioned structure. Glue the sponge,
The inner wall is rotated and moved in the circumferential direction.

FIGS. 4 and 5 show a time chart and a coating film model of a conventional coating method, respectively. In particular, FIG. 4 is a time chart showing the time variation of the sponge position on the neck wall of the funnel and the carbon paint supply, and FIG.
Is a coating film model schematically showing the formation state of the carbon coating film related to the time in FIG.

As shown in FIG. 4, while supplying carbon paint, it is applied from the upper end which is the neck seal line (NCL) of the funnel to the lower end which is the specified end, and is temporarily retained at the lower end, and then continuously from the lower end to the upper end. Application. On the other hand, the supply of carbon paint is interrupted during the ascending coating process.

[0006]

As described above, formation of a conductive film using a sponge which rotates in the circumferential direction of the neck tube and moves up and down in the tube axis direction is performed as shown in FIG.
Accordingly, the thickness of the carbon coating film 9 on the neck portion 2 of the funnel 3 is likely to be thinned upward (5 to 8 μm), and the coating film is likely to be uneven. Further, in order to increase this film thickness, the above-mentioned coating was performed twice with a drying step in the middle, but the film thickness uniformity was not obtained. Therefore, it becomes difficult to obtain the effect of suppressing the discharge current.

Therefore, an object of the present invention is to provide a method of applying a conductive material to the neck portion of a cathode ray tube body which can obtain a stable and uniform thick film thickness.

[0008]

According to the present invention, there is provided a method for spin-coating a conductive material onto a predetermined width region of a neck portion of a funnel tube by using a coating means capable of impregnating a melt. After impregnating a predetermined amount of the conductive material melt in the coating means, sequentially coating the conductive material from the upper end to the lower end of the predetermined width region, and further continuously coating from the lower end to a predetermined height, A step of supplying a predetermined amount of the conductive material to the coating means while continuing the rotation of the coating means at the time of coating to a predetermined height, and then applying the conductive material to the upper end of the predetermined width region And a method for applying a conductive material to the neck portion of the cathode ray tube body.

[0009]

According to the present invention, as shown in the position of the sponge applying means 4 in FIG. 2 and the time chart of the coating material (conductive material) supply, the first coating material supply is performed by the start of coating, and then the predetermined width region is reached. Since the coating is applied from the top to the bottom of
More paint is applied first than later. Therefore, the conductive film (coating film) is thinner in the lower portion than in the upper portion.

Further, after reaching the lower end, the application is continued while raising the coating means to a predetermined height, and when the coating height is raised to the predetermined height, the second coating material is supplied. Since the coating is applied to the upper end, the paint moves toward the specified lower end by its own weight. Therefore, the thickness of the lower portion of the above-mentioned coating film is increased.

Therefore, the formation of a coating film which becomes thinner toward the lower part by the first coating material supply and the formation of a coating film which becomes thinner toward the lower part due to the second coating composition supply cancel each other out, resulting in uniform and A conductive film having a thicker film thickness than that of a conventional one is formed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial schematic view of a coating apparatus for carrying out the method of the present invention.

As shown in FIG. 1, carbon paint as a conductive material is impregnated into a sponge 4 as a coating means through a tube 5. The sponge 4 is provided at the tip of the sponge attachment shaft 1 which is vertically movable and rotatable. Using this sponge 4, carbon paint is applied to the neck portion 2 of the funnel 3 of the cathode ray tube along the tube wall 7.

The paint region is the entire pipe wall 7 of a predetermined width region from the upper end as a neck seal line (NCL) of the neck portion to the lower end as a defined end.

FIG. 2 which is a time chart showing the sponge position on the tube wall and the time change of carbon paint supply,
A description will be given with reference to FIG. 3 of the coating film model schematically showing the formation state of the carbon coating film in relation to the time shown in FIG.

In this embodiment, as shown at the time of FIG. 2, an amount of carbon paint corresponding to the impregnated amount of the sponge is supplied until the start of application, and then the application of carbon paint is performed as shown in the time region. Starting from the upper end (NCL) of the predetermined width region, the coating is applied to the lower end which is the specified end while sequentially rotating and descending in the circumferential direction of the neck portion 2 at a constant speed, and after holding for a short time, it is shown in the time region. While continuing to raise the sponge 4 from the lower end, the application is continued up to a height of 4 to 5 mm (point P). Carbon paint is not supplied in the area of time.

As shown in FIG. 3, the coating film model in the area of time is such that the thickness of the carbon coating film gradually decreases from the upper end to the lower end in the first area. This is because during this time, the carbon paint is not supplied as described above. In the next region, only the lower part is re-applied, so that the part A is thicker than the upper part in the carbon coating film 9
Are formed.

Next, in the region of the time chart of FIG. 2, the sponge 4 stops rising only by rotation at the lower end 4-5 mm (point P), and the carbon paint is supplied in that state. Therefore, as shown in the coating film model of FIG. 3, the thickness of the carbon coating film becomes thicker at 4-5 mm.
Thereafter, as shown in the area of FIG. 2, while the carbon paint is being supplied, the spin coating is rapidly performed to the upper end. As a result, the coating film model is shown in FIG.
The film thickness was averaged from above and below, resulting in a thickness of approximately 10 to 15 μm. The reason why the thickness is almost averaged is that the carbon paint thickened at the point P in FIG. 3 moves by its own weight and contributes to the averaging at the point P, while the second coating film is above the point P. Although it gradually becomes thinner (moves to the lower part due to the weight of the paint itself), it is considered that the first coating film is offset by being thickly applied at the upper part and is made uniform.

In this embodiment, the height of the point P is set to 4 to 5 mm, but it can be appropriately changed depending on the neck diameter and the viscosity of the carbon paint.

Although a sponge is used as the coating means in this embodiment, any material that can be impregnated with the melt conductive material, such as a brush, can be appropriately used.

[0022]

As described above, according to the present invention, a stable and thick conductive film having a uniform thickness can be formed on the neck portion of the funnel tube. Therefore, the effect of suppressing the discharge current can be sufficiently obtained.

[Brief description of drawings]

1 is a partial schematic view of a coating apparatus for carrying out the method of the present invention.

FIG. 2 is a time chart showing changes over time in sponge position and carbon paint supply, which is an embodiment of the present invention.

FIG. 3 is a coating film model schematically showing a formation state of a carbon coating film related to time in FIG.

FIG. 4 is a time chart showing changes over time in sponge position and carbon paint supply in a conventional example.

5 is a coating film model schematically showing the formation state of the carbon coating film in relation to the time of FIG.

[Explanation of symbols]

 1 Shaft for installation of sponge 2 Neck part 3 Funnel 4 Sponge (application means) 5 Tube 7 Tube wall

Claims (1)

[Claims] 1. A method of spin-coating a conductive material onto a predetermined width region of a tube neck portion of a funnel tube using a coating means capable of impregnating a melt, wherein the coating means is impregnated with a predetermined amount of the conductive material melt. After letting
Applying the conductive material sequentially from the upper end to the lower end of the predetermined width region, further continuously applying from the lower end to a predetermined height, while continuing the rotation of the applying means at the time of applying to the predetermined height, A method for applying a conductive material to a neck portion of a cathode ray tube body, comprising the step of applying a predetermined amount of the conductive material to the applying means and then applying the conductive material to the upper end of the predetermined width region while supplying the conductive material. ..