JPH04294037A - Cathode ray tube and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a cathode ray tube having excellent appearance. CONSTITUTION:Electroconductive films 5 are formed on the front surface of a panel 1 and also the area at least from each corner to the side, and that portion of these conductive films 5 situated on the side face of the panel 1 is electrically connected with another part having different potential either directly or through a connective conductor 7. Conductive film is applied by spraying a conductive treatment liquid to the whole applicable areas continuously. The conductive treatment liquid is dripped onto the panel 1 in the condition it is rotated round the tube axis at a revolving speed below 120rpm.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube whose panel is coated with a conductive coating and a method for manufacturing the same.

0002

2. Description of the Related Art A high voltage of 20 KV or more is applied to a cathode ray tube when in use. At this time, the high voltage is applied to the phosphor coated on the inside of the panel. The outside of the panel is electrically floating and therefore carries an electric charge. That is,
The moment a high voltage is applied, it is charged up with positive charge, and gradually discharges over time until it reaches the ground potential. On the other hand, if you turn off the switch after applying a high voltage, the battery will be charged up with negative charges. Since this voltage is charged up to a high voltage exceeding 10 KV, dust in the room is attracted and adhered to the screen, resulting in deterioration of image quality.

[0003] In order to reduce this charge-up, a conductive film with a resistance of 105 to 1010 Ω/□ is formed on the outer surface of the panel, and the conductive film is connected to ground potential to discharge the charge generated on the panel surface. It is said that this is effective. (Refer to JP-A-63-76247 and JP-A-1-154445).

Conventionally, in forming a conductive film on a panel, as shown in FIG. The conductive treatment liquid 4 is spread uniformly over the panel 1 by centrifugal force to form a conductive film.

[0005] Here, in order to make the coating film uniform, the panel 1 is rotated at a speed of 120 rpm or more. For this reason, the conductive processing liquid 4 is blown away by centrifugal force, and a coating film is not formed on the side surface of the panel 1, or even if it is formed, it is extremely unstable. Therefore, conventionally, the front surface of the panel and the reinforcing band are electrically connected using another conductor. Thereby, the electric charge charged on the panel can be transferred from the panel to another potential through the conductor.

[0006]

[Problems to be Solved by the Invention] The above-mentioned prior art has a problem in that it is unsightly in appearance because it is necessary to attach a part of the conductor to the front surface of the panel.

An object of the present invention is to provide a cathode ray tube with excellent appearance and a method for manufacturing the same.

[0008]

[Means for Solving the Problem] In order to achieve the above object, a conductive film is formed on the front side of the panel and at least from the corner to the side face, and the conductive film on the side face of the panel is applied directly or with a connecting conductor. It is electrically connected to other potential parts.

In addition, in order to form a conductive film on the front surface of the panel and at least from the corner to the side surface, a conductive treatment liquid was sprayed over the entire front surface of the panel, including from the front surface to the corner. It is applied continuously to the side surface.

Furthermore, in order to form a conductive film on the front surface of the panel and at least from the corner to the side surface, a conductive treatment liquid is applied onto the panel while the panel is being rotated at a rotation speed of 120 rpm or less about the tube axis. It was dripped into the.

[0011]

[Operation] A conductive film is formed from the front and corner portions to the side surfaces of the panel. Therefore, the side surface of the panel can be directly electrically connected to another potential portion, such as a reinforcing band, without using a connecting conductor. Further, when a connecting conductor is used, the connecting conductor can be electrically connected to other potential parts from the side surface of the panel, and the connecting conductor is not exposed to the front surface of the panel.

[0012] In order to form a conductive film on the front and side surfaces of the panel as described above, a conductive treatment liquid is continuously sprayed from the front side to the side surface of the panel to form a stable coating on the side surface. A conductive film can be formed.

[0013] Also, the panel was rotated at 120 rpm around the tube axis.
When the conductive treatment liquid is dripped onto the panel while being rotated at a speed of less than m, the centrifugal force of the conductive treatment liquid is weakened and the conductive treatment liquid flows along the sides of the panel. A continuous conductive film can be formed in the area.

[0014]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A conductive film 5 is formed on the front surface, corners, and side surfaces of the panel 1, and the conductive film 5 and the reinforcing band 6 are electrically connected by a conductor 7. Here, the conductor 7 is inserted into the reinforcing band 6 from the side surface of the panel 1.
It is connected to the.

Therefore, the electric charge generated on the surface of the panel 1 is
It is discharged to the reinforcing band 6 through the conductor 7. Since the reinforcing band 6 is connected to the ground potential together with the external conductive film 8, the charges on the panel 1 are instantly discharged. In addition, in FIG. 1, 9 is an anode, and in FIG.
, 10 is a phosphor, and 11 is a shadow mask.

In this way, since the conductive film 5 is also formed on the side surface of the panel 1, there is no need to expose the conductor 7 on the front surface of the panel 1, and the reinforcing band 6 is connected to the side surface of the panel 1. It can be connected to the outside without making it look unsightly.

In the above embodiment, the case where the conductor 7 is provided has been described, but if the conductor film 5 is formed in direct contact with the reinforcing band 6, the conductor 7 may not be provided. .

Next, a method for forming the conductive film 5 will be explained. As shown in FIG. 3, first, a conductive treatment liquid 13 is sprayed onto the entire front surface of the panel 1 using the spray nozzle 12 to form a conductive film. Thereafter, the conductive treatment liquid 13 is similarly sprayed from the blend R section (corner section) of the front surface of the panel 1 toward the side surface using the spray nozzle 12 . Thereby, a continuous conductive film 5 can be formed from the front surface to the side surface of the panel 1.

Further, as shown in FIG. 4, when using the conventional spin coating method, the rotation speed of the panel 1 is set to 120 rpm.
Conductive treatment liquid 4 is applied to panel 1 from injection nozzle 3 as follows.
Drip on top. This weakens the centrifugal force and the panel 1
Since the conductive processing liquid 4 flows down along the side surface of the panel 1, a conductive film 5 is formed on the side surface of the panel 1, which is continuous from the front surface. In addition, in the method shown in FIG. 4, panel 1 is
After spin-coating the conductive treatment liquid 4 by rotating it at 120 rpm or more, the side surface of the panel 1 may be coated with a brush.

[0020]

According to the method of the present invention, since the conductive film is formed from the panel corner portions to the side portions as well, the panel side portions can be electrically connected directly to other potential portions such as reinforcing bands. Further, when a conductor is used, the side surface of the panel can be electrically connected to other potential parts using the conductor, and the conductor is not exposed to the front surface of the panel. Therefore, a cathode ray tube with excellent appearance can be obtained.

[Brief explanation of drawings]

FIG. 1 is an external view of a cathode ray tube according to an embodiment of the present invention.

FIG. 2 is an explanatory cross-sectional view of a panel portion of the cathode ray tube in FIG. 1;

FIG. 3 is an explanatory diagram of a method for manufacturing a cathode ray tube according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a method of manufacturing a cathode ray tube according to another embodiment of the present invention and a conventional example.

[Explanation of symbols] 1 Panel 3 Injection nozzle 4 Conductive treatment liquid 5 Conductive film 6 Reinforcement band 7 Conductor 12 Spray nozzle 13 Conductive treatment liquid

Claims (3)

[Claims] Claim 1: In a cathode ray tube having a conductive film on the outer surface of the panel, the conductive film is formed on the front surface of the panel and at least from the corner to the side surface, and the conductive film on the side surface of the panel is coated directly or with a connecting conductor. A cathode ray tube characterized in that it is electrically connected to other potential parts. Claim 2: In a method for manufacturing a cathode ray tube having a conductive film on the outer surface of the panel, a conductive treatment liquid is sprayed over the entire front surface of the panel, and also continuously on the side surface including the front surface and the corner. A method for manufacturing a cathode ray tube, characterized in that the coating is performed using 3. In a method for manufacturing a cathode ray tube having a conductive film on the outer surface of the panel, the panel is separated by 12
A method for manufacturing a cathode ray tube, which comprises dropping a conductive treatment liquid onto the panel while rotating at a rotational speed of 0 rpm or less to form a conductive film from the front and corner to side surfaces of the panel.