JP2827894B2 - High voltage leak detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage leak detector, and more particularly to a high-voltage leak detector for judging whether or not an electrical insulation state is present at a frit seal between a funnel of a bulb and a face panel in the manufacture of a color cathode ray tube. It concerns the device.

[0002]

2. Description of the Related Art For example, a bulb 1 made of lead glass or the like used in a conventional color cathode ray tube has a trumpet-shaped funnel 3 integrally having a neck 2 and a substantially planar face, as shown in FIG. In general, the panel 4 is bonded to the panel 4 by sealing it with an electrically insulating frit glass. On the other hand, an inner conductive film 6 such as graphite is formed on the inner surface of the valve 1 from the neck 2 to the funnel 3 to the vicinity of the frit seal portion 5. An anode button 7 is provided, which is electrically connected to the outside and led to the outside.

The interior conductive film 6 is electrically connected to the high-voltage electrode of the electron gun which is finally sealed in the neck 2 at the neck side end of the funnel 3, and has a frit seal at the face panel side end. In the vicinity of the portion 5, the metal gun is electrically connected to a metal back film extending from the inner surface of the face panel 4 by contact pins (not shown), and is applied with a high voltage from the anode button 7 via the interior conductive film 6 and the electron gun. Of the high voltage electrode and the metal back film are kept at a high voltage state.

For example, if the end face of the frit glass 3 or the face panel 4 is dirty, or if bubbles are generated in the frit glass, when a high voltage is applied in actual use of the color cathode ray tube, the frit seal portion 5 cannot be used. If the electrical insulation is not sufficiently ensured, high voltage leaks inside and outside the bulb 1 may cause dielectric breakdown, resulting in a fatal defect. For this reason, in the production of a color cathode ray tube, it is necessary to check in advance whether or not the electrical insulation of the frit seal portion 5 is secured.

Therefore, in the manufacturing process of the color cathode ray tube, the frit seal portion 5 is inspected by a high voltage leak detecting device. As shown in FIGS. 4 and 5, this high-voltage leak detecting device includes a rod-shaped contact pin 9 which contacts an anode button 7 of a funnel 3 and is supplied with a high voltage from a high-voltage power supply 8; A contact electrode 1 made of an umbrella-shaped rubber insulating cap 10 which is in close contact with the outer surface of the funnel 3 while being supported so as to surround it.
1 and a frame-like detection electrode 13 connected to a frit seal portion 5 which is fitted to and comes into contact with the frit seal portion 5 to detect the presence or absence of a leak electrode.

[0006] To detect a high voltage leak, a high voltage is applied from the high voltage power supply 8 to the interior conductive film 6 through the contact pin 9 of the contact electrode 11 and the anode button 7 in contact with the contact pin 9. By the application of the high voltage, the measuring device 12 detects the amount of leak current flowing from the inner conductive film 6 on the inner surface of the funnel 3 to the frit seal portion 5 and leaking through the detection electrode 13, and If the leak current is equal to or higher than a predetermined level, the electrical insulation of the frit seal portion 5 is not ensured, and the valve 1 becomes defective.
The electric insulation at the frit seal portion 5 is good, and the valve 1 becomes a good product.

In the detection of the leak current by the above-described conventional high-voltage leak detection device, when the contact electrode 11 is mounted, a syringe (not shown) is used to ensure that the peripheral portion of the insulating cap 10 is in close contact with the outer surface of the funnel 3. The insulating cap 10 is elastically deformed and pressed against the outer surface of the funnel 3.

However, the insulating cap 10 by the cylinder
Is applied to the contact electrode 1 prior to application of a high voltage.
5, and the outer surface of the funnel 3 is rough as shown in most parts of FIG. 10 has low adhesion at the periphery. As a result, application of a high voltage by the contact pin 9
A leakage current is generated along the outer surface of the funnel 3 along the detection electrode 13.
And a creeping discharge current flows between the contact pin 9 and the detection electrode 13.

When the creeping current flows on the outer surface of the funnel 3, the leak current detected by the measuring device 12 by the detecting electrode 13 is not limited to the leak current flowing through the inner conductive film 6 on the inner surface of the funnel 3, Funnel 3
And a creeping discharge current and / or a creeping discharge current on the outer surface are added. Then, there is almost no leak current flowing through the inner conductive film 6 on the inner surface of the funnel 3 and detected through the frit seal portion 5, and even if the valve 1 is to be a good product, the creepage leak current on the outer surface of the funnel 3 In addition, due to the creeping discharge current, the product is erroneously determined to be a defective product, and there is a problem that the reliability of high voltage leak detection is reduced and the product yield is also reduced. to solve this problem,
A method of analyzing a leak current waveform detected by applying a pulsed high voltage and separating and detecting a resistive creepage leak current and a creepage discharge current and a leak current of a capacitive frit seal portion is disclosed in Japanese Unexamined Patent Application Publication No. H10-157,197. 58-89760.

[0010]

As described above, due to poor adhesion of the peripheral portion of the insulating cap 10, the funnel 3
A creeping leak current or a creeping discharge current occurs on the outer surface, which lowers the reliability of high-voltage leak detection. There is a problem that a generator and a current waveform analyzer are required.

[0011]

According to the present invention, there is provided a contact electrode to which a high voltage from a high voltage power supply is applied in contact with an anode button of a funnel of a valve and a frit seal portion between the funnel and the face panel. In a high voltage leak detection device comprising a measuring electrode for detecting the presence or absence of a leak current and a detection electrode in contact with the contact electrode, the electric insulation of a volume capable of immersing a valve on the funnel side from around the contact portion between the contact electrode and the anode button. An electrically insulating liquid-filled cup that can be locally immersed only around the contact portion between the liquid tank or the contact electrode and the anode button, or an electrically insulating liquid is sprayed around the contact portion between the contact electrode and the anode button. A mechanism for immersing the periphery of the contact electrode in an electrically insulating liquid, such as a device for performing That. It is desirable to use fluorocarbon as the electrically insulating liquid.

[0012]

According to the high voltage leak detector of the present invention, the outer surface of the funnel around the contact portion between the contact electrode and the anode button is covered with the electrically insulating liquid, so that the electrical insulation of the outer surface of the funnel is ensured, and the outer surface of the funnel is secured. Since no creeping current flows, only the leak current at the frit seal portion can be detected. Therefore, erroneous determination can be prevented. In addition,
If fluorocarbon, which has good volatility and is nonflammable, is used as the electrically insulating liquid, there will be no residual electric insulating liquid in the valve, eliminating the need for cleaning for removal. Safety can be ensured.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a high voltage leak detection device showing one embodiment of the present invention. FIG. 2 is a configuration diagram of a high voltage leak detection device showing a second embodiment of the present invention. FIG. 3 is a configuration diagram of a high-voltage leak detection device according to a third embodiment of the present invention. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, reference numeral 14 denotes an electrically insulating liquid 15.
(For example, fluorocarbon), 16 is a contact electrode, and is an electrode support so that when the valve 1 is mounted on the valve holder 17, it is pressed against the anode button 7 provided on the outer surface of the funnel 3 of the valve 1. A nitrogen gas blowing nozzle 19 is provided in the opening of the neck 3 so that the body 15 does not enter. And the frit seal portion 5 by the high voltage leak detection device
Is performed by mounting the valve 1 on the valve holder 17 and externally fitting the detection electrode 13 to the frit seal portion 5. Then, a high voltage is applied from the contact electrode 16 to the interior conductive film 6 via the anode button 7, and the outer surface of the funnel 3 around the contact electrode 16 is covered with the electrically insulating liquid 15. The creepage leak current and the creepage discharge current flow, and only the leak current of the frit seal portion 5 is detected.

In a second embodiment of the present invention, as shown in FIG. 2, a tip of a contact electrode 16 is supported so as to surround the contact electrode 16 and is supplied with an electrically insulating liquid 15. Since the mechanism 20 has the electrically insulating liquid filling cup 21 connected thereto, the outer surface of the funnel 3 around the contact electrode 16 is covered with the electrically insulating liquid 15 also in this example. Even if such a large tank is not used and the amount of the expensive electric insulating liquid 15 used is reduced, no creeping leak current or creeping discharge current flows, and only the leak current of the frit seal portion 5 is detected. In this case, the electrically insulating liquid 15 that overflows and scatters from the peripheral portion of the filling installment 21 is collected by the collecting container 22 installed below.
Collected and reused. Further, the third embodiment of the present invention comprises an injection device 24 having an injection nozzle 23 for the electrically insulating liquid 15 as shown in FIG. 3. According to this embodiment, the contact electrode 16 and the anode Irrespective of the pressing direction of the button 7, the outer surface of the funnel 3 around the contact electrode 16 is covered with the electrically insulating liquid 15, so that no creeping leak current or creeping discharge current flows, and the frit seal portion 5 leaks. Only electrodes are detected. Therefore, for example, the valve 1 may be turned down such that the face panel surface faces downward.
The degree of freedom of the supporting method is increased, and handling in the inspection process can be facilitated. In this embodiment as well, a collection container 22 for the scattered electrically insulating liquid 15 is provided in the stock, collected and reused.

[0015]

As described above, according to the present invention, in detecting a high voltage leak in the frit seal portion of the color cathode ray tube, the outer surface of the funnel around the contact portion between the contact electrode and the anode button is covered with the electrically insulating liquid. Therefore, the creeping leak current and the creeping discharge current on the outer surface of the funnel can be reliably prevented, so that only the leakage at the frit seal portion can be detected. Therefore, the reliability of high voltage leak detection can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a high-voltage leak detection device showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a high-voltage leak detection device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a high-voltage leak detection device showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional high-voltage leak detection device.

FIG. 5 is a partially enlarged view of a conventional high voltage leak detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve 3 Funnel 4 Face panel 5 Frit seal part 7 Anode button 8 High voltage power supply 10 Insulating cap 12 Measuring instrument 13 Detection electrode 14 Liquid tank made of electric insulation 15 Electric insulating liquid 16 Contact electrode 19 Nozzle 20 Supply mechanism 21 Filling cup 23 Injection Nozzle 24 injection device

Claims (3)

(57) [Claims] 1. A contact electrode to which a high voltage from a high-voltage power supply is applied by contacting an anode button provided on a funnel of a valve and a frit seal portion between the funnel and the face panel to detect the presence or absence of a leak current. In a high-voltage leak detection device comprising a detection electrode connected to a measuring device to be connected, a contact between the contact electrode and the anode button is provided.
A volume that allows the funnel-side valve to be immersed from around the contact area
A high-voltage leak detection device, wherein the periphery of the contact electrode is immersed in an electrically insulating liquid using an electrically insulating liquid tank . 2. An anode button provided on a funnel of a valve.
Contact with the high voltage from the high voltage power supply
Electrode, frit between funnel and face panel
Measuring instrument that detects the presence or absence of leak current by contacting the seal
High-voltage leak detection device consisting of a detection electrode connected to
An electrically insulative liquid filling that can locally immerse only around the contact portion between the contact electrode and the anode button.
Electrical insulation around the contact electrode using a cup
A high voltage leak detector characterized by being immersed in a liquid . 3. The electrical insulation according to claim 1, wherein
A high voltage leak detection device, wherein the ionic liquid is fluorocarbon .