JPS6350815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coating an inner conductive film on a cathode ray tube such as a color picture tube, and a conductive film coating apparatus used therein.

Generally, in a cathode ray tube, such as a color picture tube, a conductive film 2 is coated on the inner surface of the funnel portion and the neck portion of the tube body 1 during the manufacturing process, as shown in FIG. This inner conductive film 2 normally has a high voltage applied function to accelerate the electron beam, a function to capture secondary electrons generated from a color selection electrode, etc., or a high temperature power supply by forming capacitance with the outer surface conductive film. It functions as a smoothing capacitor. Therefore,
This inner conductive film 2 needs to be uniformly formed with a predetermined thickness.

Conventionally, as a method of coating and forming such an inner surface conductive film 2, a method as shown in FIG. 2, for example, has been proposed. As shown in the figure, a tube body 1 having an integrated funnel portion and a neck portion is rotatably installed via supports 3 and 4 so that the tube axis is directed upward from a certain level of horizontal direction. On the other hand, a so-called brush 6 having forward, backward, upward, and downward functions and having a sponge 5 at its tip is installed along the tube axis of the tube body 1. Then, bring the brush 6 at the tip close to the carbon container 7, and put the sponge 5 at the tip.
After impregnating the sponge 5 with an appropriate amount of carbon by bringing it into contact with the rotor 9 (rotated by the motor 8 to stir the carbon) in the carbon container 7, the brush 6 containing this carbon is moved up and forward to remove the carbon from the tube. body 1
It enters from the neck side, moves a predetermined distance, and then descends to bring the sponge 5 into contact with the inner surface of area A of the neck part, and in synchronization with this, the tube body 1 is rotated to apply carbon to area A. Thereafter, the brush 6 is raised and retreated to return to its original position. still,
Carbon coating in areas B and C of the funnel portion is performed in a separate operation, and in particular area B is applied by hand with a brush. Incidentally, the advancement of the brush 6 within the neck portion is controlled with reference to the installation position of the deflection yoke of the tubular body 1.

In addition, a coating method has also been proposed in which, for example, the tube body 1 is rotated while the brush 6 is inserted from the funnel side, and the brush tip is configured to be curved, and carbon is coated from area A to B. ing.

However, in such conventional methods, when the brush 6 rises and separates from the inner surface of the tube after the carbon coating is finished, a discontinuous surface of carbon tends to occur at that part, and the carbon remains in a band shape, resulting in a uniform coating surface. It is impossible to measure the carbon content, and if the carbon peels off, it will have a negative impact on the product. In addition, because the brush is impregnated with carbon by contacting the roller, it is difficult to adjust the amount of carbon, and furthermore, since the brush is rotated, rationalization and automation of the work are hindered.

In view of the above-mentioned points, the present invention provides an inner conductive film that uniformly coats a conductive film to a predetermined thickness on the inner surface spanning from the neck part to the funnel part of a cathode ray tube, and makes it possible to streamline and automate the work. The present invention provides a coating method and a conductive film coating apparatus therefor.

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

FIG. 3 shows a coating device used in the method for coating an internal conductive film of the present invention, and in the same figure,
Reference numeral 11 denotes a so-called coating member comprising a rod shaft 12 and a brush 13 made of sponge, felt or the like impregnated with a conductive coating agent. The application member 11 is vertically mounted via a rotation mechanism 14, and the rod shaft 12 is configured to rotate when the rotation mechanism 14 is driven. In this case, the rotation mechanism 14 is rotationally driven by a rotation motor 15 via a timing belt. The brush 13 at the tip is rotatably attached to the rod shaft 12 about a fulcrum 16 in a direction in which the brush surface faces upward, and the rod shaft 12 is tilted to the application member 11 so that the brush 13 can be attached to the funnel portion and Means 17 is provided for bringing the neck portion into abutment along the inner surface of the integral tube body 1. This means 17, as shown in FIG. 12 is biased in the direction of arrow a by a spring 21, and a restraining ring 22 into which the support member 18 and the rod shaft 12 are inserted is arranged, and the pneumatic cylinder 23
When the ring body 22 is in the downward position (solid line position), the rod shaft 12 is maintained in a vertical state by the ring body, and when the ring body 22 is moved upward (dotted line position), the rod shaft 12 is maintained in the vertical position by the ring body. 22 and tilted in the direction of arrow b by the spring 21.

On the other hand, the application member 11 is disposed on the intermediate base 24 and is configured to be movable in the vertical direction together with the intermediate base 24. That is, the intermediate base 24 is supported by a feed screw 26 provided on the lower base 25, and is raised and lowered by rotationally driving the feed screw 26 by a continuously variable speed motor 27 via a timing belt. It will be done. In this case, the intermediate base 24 is slidably guided via the ball bush 28 along a plurality of guiding shafts 29 that are installed on the lower base 25. Also, on the lower base 25, there are switches 30 and 31 which are integrally connected to the intermediate base 24 at two positions in the vertical direction and which are in contact with the intermediate base 24, respectively, and for defining the raised position and the lowered position of the intermediate base 24. will be provided. In addition, on the application member 11 side, the rod shaft 12 is expanded and contracted to form the brush 1.
A coating position setting adjustment mechanism 32 is provided for adjusting the position No. 3, that is, the coating position.

Further, a means 33 is provided for intermittently supplying a conductive coating agent, for example, a carbon coating agent, to the brush 13 of the application member 11. This means 33 includes a carbon container 35 equipped with a stirring means 34, and this container 3.
It is composed of a pump device 36 that adjusts the carbon coating agent in the brush 5 to a predetermined amount and quickly pumps it out, and a pipe 38 that guides the carbon coating agent from the carbon coating agent to the brush 13 via a rotating joint 37. 39 is a coating amount adjustment dial, and 40 is a switch.

The present invention uses such a coating device, and first,
The tubular body 1 is placed on a mounting table 42 having a through hole 41 in the center as shown in FIG. At this time, the axes of the applicator 11 and the tube body 1 are approximately aligned. When the continuously variable speed motor 27 rotates in this state, the intermediate base 24 is raised at high speed by the feed screw 26, and the application member 11 enters the tube body 1 through the opening of the funnel portion. and,
When the switch 31 is pressed at a predetermined raised position of the intermediate base 24, the intermediate base 24 is stopped, and the brush 13 at the tip of the applicator 11 is brought to a predetermined position within the neck portion. (Fig. 5B) Next, when the pneumatic cylinder 23 is driven and the tube rises and is removed from the rod shaft 12, the rod shaft 12 is tilted by the spring 21 and the brush already impregnated with an appropriate amount of carbon coating agent is moved. 13 comes into contact with the inner surface of the neck portion of the tube body 1. The brush 13 is driven by a motor 15 and rotates through a rotating mechanism 14 to remove the carbon film 2.
Start applying. (Fig. 5C) Then, after the brush 13 has gone around once and coated the upper edge of the neck part, it is lowered at low speed by the motor 27 while rotating, and is lowered from the neck part along the inner surface of the funnel part by the tension of the spring 21. However, the carbon film 2 is applied from region A to region B.
(FIG. 5D) At this time, since the brush 13 freely rotates around the fulcrum 16, it follows well the fluctuation of the curved surface from the neck portion to the funnel portion.

When the brush 13 descends to a predetermined position together with the intermediate base 24, the switch 30 is pressed to stop the intermediate base 24 from descending and the rotation of the brush 13. Then, the pneumatic cylinder 23 contracts and the ring body 22 is lowered, and the application member 11 returns to the vertical state (FIG. 5E). At this time, an appropriate amount of carbon coating agent is supplied to the brush 13 from the carbon coating agent supplying means 33 to prepare for coating the next tube body.

According to the present invention described above, the conductive film, that is, the carbon film 2, is coated and formed by fixing the tube body 1 and rotating the brush 13 downward, so that the raising of the brush in the case of the conventional method of rotating the tube body 1 is avoided. The occurrence of discontinuous surfaces during coating is prevented, and a carbon film 2 of uniform height is formed on the inner surface. Therefore, occurrence of peeling of the carbon film 2, etc. is prevented, and this also has a favorable effect on voltage resistance defects. Further, since continuous coating can be automatically performed from area A of the neck area to area B of the funnel area, which was conventionally painted by hand with a brush, the time required for unit work can be shortened. Furthermore, since the tube body 1 is fixed, it is possible to streamline and automate the work that was impossible with the conventional tube rotation method. The tubular body 1 is disposed facing downward with respect to the sealing surface of the funnel portion, and a coating member is introduced from the funnel opening side to perform coating. Therefore, even if the conductive coating agent drips onto the funnel side, it will not cause any problem since the conductive coating agent will be applied to the conductive layer C next. Then, in this way, apply to areas A and B from the neck part to the funnel part,
Since the next region C of the funnel portion can be coated continuously, the so-called interior carbon coating can be easily automated. Furthermore, when impregnating the brush 13 with the carbon coating agent, in the past it was difficult to adjust the amount of impregnation because it was brought into contact with a roller, but in the present invention, the amount of impregnation is difficult by using the pump device 33. This makes it possible to finely adjust the carbon film 2 of uniform thickness on each tube.

Furthermore, when applying carbon, the application member 11 is introduced from the funnel opening side and brought to a predetermined position inside the neck, so the application member 11 may accidentally touch other parts of the inner surface of the neck that should not be coated. This prevents carbon from adhering to the surface.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a tube used for explaining the present invention;
FIG. 2 is a layout diagram showing an example of a conventional conductive film coating method, FIG. 3 is a perspective view showing an example of a conductive film coating apparatus according to the present invention, FIG. 4 is a side view of the main parts, and FIG.
The figure is an explanatory diagram of the operation. 1 is a tube body, 2 is a conductive film, 11 is a coating member, 13
14 is a brush, 14 is a rotating mechanism, 24 is an intermediate base that moves up and down, and 33 is a supply means for a conductive film coating agent.

Claims (1)

[Scope of Claims] 1. When coating and forming a conductive film on the inner surface spanning from the neck part to the funnel part of a cathode ray tube, the tube body in which the funnel part and the neck part are integrated is set with the sealing surface of the funnel part as a reference. The coating member is fixedly arranged downward, is introduced from the funnel opening side, and is impregnated with a conductive coating agent on the inner surface of the tube, and is rotated while moving in the tube axis direction to apply the coating. A method for coating an inner conductive film in a cathode ray tube, characterized by: 2. A coating member impregnated with a conductive coating agent and introduced from the funnel opening side fixedly arranged downward; a means for intermittently supplying the conductive coating agent to the coating member; and a means for intermittently supplying the conductive coating agent to the funnel portion. A conductive film coating device comprising means for bringing the neck portion into contact along the inner surface of an integrated tube body, and means for rotating and moving the coating member in the tube axis direction.