JPS628429A - Inner high voltage circuit tester for cathode-ray tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an internal high voltage testing circuit device for cathode ray tubes, and in particular, in the manufacturing process of cathode ray tubes, the quality of the internal high voltage circuit is checked, and after the product is completed. This invention relates to an internal high voltage circuit inspection device for cathode ray tubes that can screen out defects in cathode ray tubes.

[Technical background of the invention and its problems]

An example of a cathode ray tube incorporating a unipotential electron gun will be explained with reference to FIG.

That is, a phosphor screen (2) is formed on the inner surface of the face plate (ω), and a funnel (2) connected to this face plate is provided with an anode terminal (anode button) and an internal conductive film (0). is funnel■
It is formed up to the top of the neck (to) which is connected to.

Also, inside the neck 0 are a heater (11), a cathode (12),
The first electrode (13), the second electrode (14), the third electrode (I
s), a 49th pole (16), and a 5f11th pole (17) are arranged, the third electrode (15) and the fifth electrode (17) are connected by a connecting line (18), and the fifth electrode ( 17) has a pull spring (1) connected to the internal conductor ff1) FX■.
9) are provided.

When the cathode ray tube described above is in operation, the anode terminal is connected to the internal conductive film () through the valve spring (19) to the third
Pole (15) 5th pole (17) D 10-30KV
(7) High [pressure is applied, heater (11), cathode (1z
), the first electrode (13), the second electrode (14) and the fourth electrode (
A predetermined voltage is applied to 16).

In this case, the electrical connection between the internal conductive film (1) and the valve spring (19) depends on the contact resistance, which is caused by a decrease in the elasticity of the valve spring (19) during heating during the manufacturing process of the cathode ray tube. It changes due to defects in the internal conductive film (c) due to high voltage treatment, etc.

Conventionally, this valve spring (19) and an internal conductive film ■
Continuity tests with the internal high-voltage circuit, that is, internal high-voltage circuit tests, were carried out with the cathode ray tube installed and by checking the screen fluctuations drawn on the phosphor screen. Since a high voltage is applied from the ( ), if there is a poor contact, continuous sparks will cause conduction, making it difficult to distinguish between good and bad. If used.

There were problems such as damage to the neck 0 due to impact and heat generated by sparks from the poor contact area.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and
It is an object of the present invention to provide an internal high-voltage circuit inspection device for a cathode ray tube that can reliably determine the conduction state from the anode to the anode voltage application electrode in a short time.

[Summary of the invention]

That is, one aspect of the present invention is that a heater, a cathode, a first electrode, a second electrode, other electrodes, and an anode voltage application electrode are installed inside the neck, and an internal conductive film is formed from the funnel provided with the anode terminal to the neck. ￥A pole J! Equipped with an internal high voltage circuit in which the internal conductive film and the anode voltage application electrode are electrically connected by a valve spring. In the tube internal high voltage circuit inspection device, a cathode heating power source that heats the cathode via a heater, a second electrode power source provided between the second electrode and the connection line of the lIa electrode and the first @ electrode; It is characterized by comprising at least an anode power supply having a desired value higher than the second electrode power supply provided between the connecting wire and the anode terminal, and by measuring the cathode current and the anode current to inspect the internal high voltage circuit. This is an internal high voltage circuit inspection device for cathode ray tubes.

[Embodiments of the invention]

Next, an embodiment of the internal high voltage circuit inspection apparatus for a cathode ray tube according to the present invention will be described with reference to FIG. 1 for a cathode ray tube incorporating a unipotential electron gun. However, the same reference numerals as in FIG. 4 indicate the same parts and will not be particularly described.

That is, the heater (11) is supplied with the rated voltage from the heater power source (21). In addition, the cathode (12) and the first electrode (13
) is connected with the connecting line (22), and this connecting line (22)
A cathode ammeter (23) and a second electrode power source (24) are provided between the and the second f21 pole (14). This second electrode power source (24) supplies the second electrode (14) with a rated voltage or a voltage lower than the rated voltage, loo to 400V. In addition, the negative electrode and the anode terminal (a) of the power supply for the second t1i electrode (24)
An anode power supply (25) that supplies a voltage slightly higher than that of the second electrode power supply (24) and an anode fIi current meter (26) are connected between them. All of the electron beams emitted from the cathode (12) by applying such a voltage are
It is captured by the tt electrode (15) and the fifth ffi electrode (17), and when the internal high voltage circuit is good, it flows into the valve spring (19) via the internal conductive film 0 to the anode terminal), and the anode ammeter (26) detects a predetermined value. It shows the current value and also shows the cathode ammeter (23
), but if the internal high-voltage circuit is defective, no current flows to the anode terminal (), the anode ammeter (26) becomes almost zero, and the cathode ammeter (23) However, only the current corresponding to this current flows, and it is possible to check whether the internal high voltage circuit is good or bad based on the current values of these ammeters (23) and (26).

The relationship between the voltage of the power supply for the second FFI electrode and the anode voltage described above is as shown in Fig. 2, where the horizontal axis is the anode voltage and the vertical axis is the anode current. When it is the same as the voltage for the second electrode or when it is lower, the curve (31)
In addition, in the high-resolution type where the pore diameter of the third grid (15) is 50% or less of the normal one, the anode current temporarily becomes zero and becomes negative as shown in curve IJA (32), and curve m ( It is difficult to distinguish it from the internal high voltage circuit failure shown in 33).

In addition, as can be seen from curve (33), when the voltage exceeds 50 to 100 V from the second electrode power source, the conduction failure part of the internal high voltage circuit causes dielectric breakdown and anode current begins to flow, making it difficult to distinguish that the internal high voltage circuit is defective. However, it is also unfavorable in terms of insulation of the anode ammeter (26).

The anode voltage determined in the experiment is 20 V or more than the second electrode voltage.
It was necessary and sufficient to test at a 30V higher voltage. - The above-mentioned embodiments are described for a cathode ray tube equipped with a unipotential electron gun, but can also be used for a cathode ray tube equipped with a pipotential electron gun.

Next, this embodiment will be explained with reference to FIG. However, the first
The same reference numerals as in the figure indicate the same parts.

That is, the funnel (2) is provided with an anode terminal (anode button) and an internal conductive film 0, and this internal conductive film is formed up to the top of the neck (0) connected to the funnel (2).
colour. Also, inside the neck 0 is a heater (11) and a cathode (12).
), a second electrode (14), and a third electrode (15).

A fourth electrode (16) is provided, and the fourth electrode (16) is provided with a valve spring (19) connected to the internal conductor'@membrane 0.

In this structure, the heater (11) has a heater power source (2
The rated voltage is supplied from 1). Further, the negative ti (12) and the first electrode (13) are connected i11. (22□), and the second electrode (14) and the third @ electrode (15) are connected, i! (22□), and this connection nc22. )A
22□) Between the cathode ammeter (23) and the second electrode t1!
A source (24) is provided. This second electrode power supply (2
4) is the rated or lower voltage than the rated voltage 100~4
It is 00v. In addition, an anode power source (25) that supplies a slightly higher voltage than the second electrode power source (24) and an anode ammeter (26) are connected between the positive electrode and the anode terminal of the second electrode power source (24). has been done. By applying such a voltage, it is possible to inspect whether the internal high voltage circuit is good or bad in the same manner as in the previous embodiment.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a cathode ray tube internal high voltage circuit testing device that can easily test the quality of the internal high voltage circuit of a cathode ray tube.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is an explanatory diagram showing another embodiment of the present invention, and FIG. 4 is a cathode ray tube having a unipotential electron gun. It is an explanatory diagram.

Claims (1)

[Claims] A heater, a cathode, a first electrode, a second electrode, other electrodes, and an anode voltage application electrode are installed inside the neck, and an internal conductive film is formed from the funnel provided with the anode terminal to the neck. A cathode heating power source for heating the cathode via the heater; and a cathode heating power source for heating the cathode via the heater; a second electrode power supply provided between the connection line of the first electrode and the second electrode; and an anode power supply having a desired value higher than the second electrode power supply provided between the connection line and the anode terminal. 1. An internal high-voltage circuit testing device for a cathode ray tube, characterized in that the internal high-voltage circuit is tested by measuring cathode current and anode current.