JPH07114110B2 - Method and apparatus for applying conductive film graphite - Google Patents

Description

The present invention relates to an apparatus for manufacturing a cathode ray tube, for example, a color picture tube, and more particularly to a method and an apparatus for depositing conductive graphite on the inner surface of a funnel.

[Conventional technology]

A cathode ray tube, for example, a color picture tube has a
On the inner surface, a shadow mask 3 having a large number of openings facing the fluorescent film 1, a funnel 4 sealed to the panel 2, a neck 5 connected through the funnel 4, and one end of the neck 5 are provided. It is composed of a stem 6 in which a plurality of stem pins are embedded in a sealing portion, and an electron gun assembly 7 assembled in the stem 6.

As shown in FIG. 5, the funnel 4 is supplied with a high voltage to an electron gun high voltage applying electrode (not shown) and forms a capacitance with an external conductive film (not shown) as shown in FIG. It is general that the neck portion conductive graphite 8 and the funnel portion conductive graphite 9 are formed on the inner surface of the neck 5 and the inner surface of the funnel 4, respectively, before being joined to the structure.

Among them, as a method of forming conductive graphite (hereinafter abbreviated as graphite) on the inner surface of the funnel, a method generally called a spray method is disclosed in JP-A-61-103855 or JP-A-61-85555.
No. 59-12457. In this method, as shown in FIG. 6, the frit seal surface of the funnel 4 and the neck portion outside the area where graphite is adhered are masked by the frit seal surface masking 10 and the neck masking 11, respectively, and the funnel diameter is increased. The graphite was sprayed from the portion mainly by the spray nozzle 12 to form the deposit. In the figure, 13 is a pump and 14 is a tank.

Further, as another method, there is a method called a brush method (not shown), in which a brush-impregnated brush (or sponge) is brought into contact with a graphite application site, and application is performed while moving the funnel or brush.

[Problems to be Solved by the Invention]

The above-mentioned conventional method for forming an adherend using a spray nozzle has the following problems. That is, (1) since the graphite is scattered in the form of mist, it is easy to enter the frit seal surface or the neck through a small gap in the masking,
The rate of failure is high.

(2) Since graphite adheres to the masking portion and gradually sticks to it, the graphite peels off during application and falls into the funnel, causing defects such as foreign matter in the tube.

(3) In order to prevent the item (2), it is necessary to frequently replace the masking portion, which causes a decrease in work efficiency.

The inventions described in the above-mentioned two patent publications are for solving the above problems, but they are not completely solved at present, and as another problem, a configuration for masking equipment and As a safety and hygiene measure for workers, local exhaust equipment was required, and there was a problem that equipment prices increased.

In addition, as a recent trend, graphite applied to a part having a circular cross section and graphite applied to a part having a substantially rectangular cross section from the neck joint part of the inner surface of the funnel are different from each other for the purpose of suppressing discharge current during discharge in a tube There is a tendency to use different types of graphite.In this case, in addition to the above-mentioned masking of the neck and frit seal surface, the spray method further adds to the boundary between the circular cross section and the rectangular cross section. There is a problem that it is necessary to perform one masking, which causes an increase in defective factors such as foreign matter in the pipe and a decrease in work efficiency.

Further, in the conventional spraying method using a spray, there is a problem in that the graphite is consumed in a large amount because it becomes a mist and scatters in addition to the graphite applied to the funnel.

In addition, in the brush method, since the shape of the inner surface of the funnel, particularly the shape of the roughly rectangular portion forms a complicated curved surface, it is difficult to move the coating member such as a brush along this curved surface. It is a method that is currently being delayed by automation, which is done by hand.

An object of the present invention is to provide a method and apparatus for coating conductive film graphite that solves the above problems.

[Differences from the Prior Art of the Invention]

In contrast to the above-described conventional conductive film graphite coating apparatus, the present invention provides (1) a coating portion having a circular cross section and a coating member having a substantially rectangular cross section for coating, and (2) a circular cross section. It is said that a coating member that is approximately the same in shape as the inner surface of the funnel is used for the coating portion that forms the area, and that a coating material that is fixed to the variable sequence robot is used for the portion that forms a roughly rectangular cross section, and that coating is performed by the brush method. There are differences.

[Means for Solving the Problems]

In order to achieve the above object, a conductive film graphite coating method according to the present invention is a conductive film graphite coating method including a first coating step and a second coating step. , With the neck part connected to the funnel facing upwards, raise the applicator holder with the applicator sponge impregnated with graphite to the part of the inner wall of the funnel that has a circular cross-section from the neck joint part and contact the inner surface of the funnel to rotate it. In the second coating step, the opening on the frit seal surface side of the funnel is faced up, and the upper part of the circular cross section of the inner wall of the funnel is placed. A coating member fixed to the arm tip of the variable sequence robot and impregnated with graphite is applied along the inner surface of the funnel to the part that has a roughly rectangular cross section up to the opening on the frit seal surface side. And applying graphite to a portion having a substantially rectangular cross section. Further, in the applying treatment in the second applying step, the graphite applied in the first applying step is polymerized before being dried. The application is started from the part.

Further, the conductive film graphite coating apparatus according to the present invention has a portion having a circular cross section from the neck joint portion of the inner surface of the funnel and a substantially rectangular cross section from the upper portion of the circular cross section to the frit seal surface side opening of the funnel. A device for depositing and forming a conductive film graphite separately on a part, wherein the device for depositing and forming a conductive film graphite on a part having a substantially rectangular cross section of the funnel includes a positioning mechanism, a variable sequence robot, A coating member, a conductive film graphite supply unit,
It has a graphite throttling mechanism, and the positioning mechanism has a tube axis direction of the funnel in which graphite is applied to a portion having a circular cross section from the neck joint part of the inner surface of the funnel and a rotation direction around the tube axis. The variable sequence robot moves the application site along a site having a substantially rectangular cross section from the circular cross section upper part of the inner surface of the funnel to the frit seal surface side opening of the funnel, The application site is fixed to the arm tip of the variable sequence robot and is for applying graphite to a site having a substantially rectangular cross section of the funnel. The conductive film graphite supply unit supplies the conductive film graphite to the application member. The graphite squeezing mechanism is for squeezing extra graphite supplied to the coating member.

〔Example〕

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

FIG. 1 is a partial cross-sectional view of an apparatus for depositing and forming graphite on the inner surface of a funnel having a circular cross section in the present invention.

In the figure, the funnel 4 is a mounting table with the neck part facing up.
The mounting table 15 is lifted by the cylinder 16 and the funnel 4 comes into contact with the funnel receiving table 17 and stops. The contact position between the funnel 4 and the funnel cradle 17 is a reference line portion (not shown) that serves as a reference for the outer surface of the funnel 4.
Therefore, the positioning of the funnel height direction and the funnel center line can be maintained with high accuracy. Also the mounting table 15
Is hollow in an area slightly smaller than the opening on the frit seal surface side of the funnel 4.

The coating holder 18 has an outer peripheral shape substantially the same as the coating range portion of the inner surface of the funnel, and three strip-shaped coating sponges 19 are attached to the coating holder 18 at equal intervals.

At the time of positioning the funnel, the coating holder 18 stands by under the mounting table 15, and graphite is supplied to the coating sponge 19 by a graphite supply device (not shown) during this time.

When the positioning of the funnel 4 is completed, the coating holder 18 starts rotating by the rotating shaft 23 of the motor 20 and starts rising by the cylinder 21 while continuing the rotation. The center line of the funnel 4 and the center line of the coating holder 18 are designed to be mechanically coincident with each other. The coating holder 18 rises on the center line and penetrates the cavity of the mounting table 15 by the stopper 22. Stop. The position of the stopper 22 is adjusted by contacting the coating sponge 19 with the inner surface of the funnel about 1 m when the coating holder 18 is stopped.
Adjust so that it can be pressed about m. This stopper 2
Since 2 has a screw on the outer circumference, fine adjustment is possible.

From the time when the coating sponge 19 contacts the inner surface of the funnel,
Application is started. This coating time can be adjusted by a timer (not shown), but the coating is completed in about 2 to 3 seconds.

After that, each part is restored in the reverse order of the above coating operation, the funnel 4 is taken out, and one cycle is completed.

Although three strip-shaped coating sponges are used in this embodiment, the shape and the number are not limited to this.

The funnel whose graphite coating is completed on the circular cross section by the present coating apparatus is carried by a pallet conveyor (not shown) to the coating apparatus having the substantially rectangular cross section.

Next, an embodiment of a coating apparatus for depositing and forming graphite on a substantially rectangular portion on the inner surface of the funnel will be described with reference to FIG.

In the figure, the funnel 4 has four outer peripheral support portions 24,
Positioning is performed by the neck chuck 25 in the tube axis direction and the rotation direction around the tube axis.

In this embodiment, an articulated robot 26 (hereinafter, abbreviated as a robot) is installed on a pedestal 27 in an upside down manner. By doing so, the operation range of the robot 26 can be effectively used.

A cylindrical coating sponge 28 is fixed to the arm tip of the robot 26 via an adapter 29. Further, a tank 31 provided with an agitator 30 and a squeezer 32 are installed within the operation range of the robot 26 near the robot 26.

During the positioning of the funnel 4, in order to supply graphite, the coating sponge 28 is moved to the tank 31 side and abuts the upper part of the stirrer 30 to impregnate graphite. However, at this point, the amount of graphite impregnated with the coating sponge 28 is generally larger than the consumption amount at the time of coating.Therefore, as the number of coatings increases, the amount of graphite impregnated in the coating sponge 28 increases, causing sagging or pooling. Easier to do. Therefore, in the embodiment according to the present invention, after the graphite is supplied to the coating sponge 28, the coating sponge is vertically moved between the squeezing bars 33 by the squeezer 32 in which the squeezing bars 33 are arranged in parallel at intervals smaller than the diameter of the coating sponge 28. The extra graphite is squeezed out by sandwiching it.

As described above, when the funnel positioning and the graphite supply are completed, the robot 26 starts the coating operation.

As for the coating order, first, coating is started from a portion where the circular cross-section formed by the coating apparatus of the embodiment shown in FIG.

Generally, when graphite that has been dried and solidified is newly overcoated with graphite, peeling of the graphite occurs in the polymerized portion. Therefore, in the present invention, after the graphite coating of the portion of the circular cross section,
This problem is solved by quickly applying the polymerized portion before the graphite dries.

After the coating of the polymerized portion, the robot 26 is configured to sequentially coat the coating sponge 28 toward the funnel frit seal surface.
Teaching of. Since the teaching can finely control the posture, the pressing force of the coating sponge 28 can be easily controlled to an optimum state in each portion of the coating.

Now, the funnel in which graphite is adhered and formed by the apparatus according to the above two embodiments has the following characteristics as shown in FIG.

(1) In the circular cross-section coating portion 34, a thin streak pattern of the coating sponge is seen in the circumferential direction.

(2) A thin streak in the circumferential direction is observed in the overlapping portion 35 between the application site having a circular cross section and the application site having a substantially rectangular cross section.

(3) In the roughly rectangular cross-section coating section 36, a thin streak pattern is seen in the direction in which the coating sponge has moved.

In contrast to the coating form of the coating apparatus according to the present invention, a line pattern is not seen by the spray method, the boundary between the coated portion and the uncoated portion is not clear, and gradually becomes blurred.

Further, in the hand-painting work by the brush method, a streak pattern of the brush is seen on the whole, but the streak of the coating and overlapping portion of the circular cross section and the rectangular cross section is not so often seen.

The streak pattern seen by the coating method and coating apparatus of the present invention is thin and does not affect the quality of the product.

〔The invention's effect〕

As described above, the present invention has a portion having a circular cross section,
The cycle time can be shortened by applying it separately to the part having a substantially rectangular cross section, and it can also be applied when different graphites are formed on the above two parts. By rapidly applying the polymerized portion after the graphite is applied to the portion of the shape cross section and before the graphite is dried, it is possible to prevent the exfoliation of the graphite in the polymerized portion where the graphite is overcoated. Further, by using the variable sequence robot for the coating device having a portion having a substantially rectangular cross section, the coating can be automated, and labor and labor can be saved. Furthermore, by having a squeezing mechanism, there is an effect that a stable coating state can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an apparatus for depositing and forming conductive film graphite on a coating portion having a circular cross section according to the present invention, and FIG. 2 is a sectional view of a device for coating conductive film graphite on a coating portion having a substantially rectangular cross section according to the present invention. FIG. 3 is a vertical sectional view of a funnel on which conductive film graphite is deposited and formed by the coating apparatus of the present invention, and FIG. 4 is a vertical sectional view showing the structure of a cathode ray tube. Fifth
FIG. 6 is a vertical cross-sectional view of a funnel showing a coating portion of internal conductive film graphite, and FIG. 6 is a perspective view of a conventional spraying method conductive film graphite coating device. 4 …… Funnel, 15 …… Standing table 16 …… Cylinder, 17 …… Funnel holder 18 …… Coating holder, 19,28 …… Coating sponge 26 …… Robot, 30 …… Stirrer 31 …… Tank, 32 ...... Squeezer

Claims (2)

[Claims] 1. A method for coating conductive film graphite, comprising: a first coating step and a second coating step, wherein the first coating step is performed with the neck portion connected to the funnel facing upward. A process of applying graphite to the circular cross section by raising the coating holder with the graphite coating impregnated sponge to the inner wall from the neck joint and contacting the inner surface of the funnel and rotating it. In the second coating step, a generally rectangular cross section from the upper part of the circular cross section of the inner wall of the funnel to the frit seal surface side opening is placed with the opening of the funnel on the frit seal surface side facing upward. An application member fixed to the arm tip of the variable sequence robot and impregnated with graphite is brought into contact with the inner surface of the funnel along the inner surface of the funnel, and the graphite is applied to the substantially rectangular cross section. Further, in the coating treatment in the second coating step, coating is started from the polymerized portion before the graphite coated in the first coating step is dried, How to apply. 2. The conductive film graphite is divided into a portion having a circular cross section from the neck joint portion on the inner surface of the funnel and a portion having a substantially rectangular cross section from the upper portion of the circular cross section to the opening on the frit seal surface side of the funnel. An apparatus for depositing and forming, wherein the apparatus for depositing and forming conductive film graphite on a portion of the funnel having a substantially rectangular cross section includes a positioning mechanism, a variable sequence robot, a coating member, and a conductive film graphite supply unit. When,
It has a graphite throttling mechanism, and the positioning mechanism has a tube axis direction of the funnel in which graphite is applied to a portion having a circular cross section from the neck joint part of the inner surface of the funnel and a rotation direction around the tube axis. The variable sequence robot moves the application site along a site having a substantially rectangular cross section from the circular cross section upper part of the inner surface of the funnel to the frit seal surface side opening of the funnel, The coating member is fixed to the arm tip of the variable sequence robot and coats graphite on a portion of the funnel having a substantially rectangular cross section. The conductive film graphite supply unit supplies conductive film graphite to the coating member. The graphite squeezing mechanism is a device for squeezing extra graphite supplied to the coating member.