JPH08316010A - Variable resistor for high voltage - Google Patents

Abstract

PURPOSE: To increase the degree of freedom in high-voltage resistor designing by electrically connecting at least one of three terminals: input terminal, exit terminal and grounding terminal, with a high-voltage resistor through a conductive rubber having a resistivity equal to or above a particular value. CONSTITUTION: An input terminal 4 and an input electrode 8c are electrically connected with each other by inserting the input terminal 4 into a conductive rubber press-bonded to the input electrode 8c. The conductive rubber 11 is made of a material formed by dispersing carbon powder or metal powder of Ag, Cu or the like in resin, such as rubber. It has a high resistivity equal to or above 1.0MΩ.cm (e.g. 15MΩ.cm). Therefore, variable resistors 8a, 8b, a coupling resistor 8g and the conductive rubber 11 function together so as to reduce high voltage. This makes it possible to reduce voltage dropped by a high-voltage resistor, which increases the degree of freedom in designing the high-voltage resistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage variable resistor for stepping down a high voltage generated in a flyback transformer to a predetermined voltage, and more particularly to a connecting means for connecting a terminal and a high voltage resistor.

[0002]

2. Description of the Related Art A conventional high voltage variable resistor 30 will be described with reference to FIGS. Fig. 2 shows high voltage variable resistor 3
0 is a side sectional view, and FIG. 3 is a plan view of an insulating substrate that constitutes the high voltage variable resistor 30.

As shown in FIG. 2, a conventional high-voltage variable resistor 30 includes an insulating case 1, an insulating substrate 2, rotating members 3 and 3, an input terminal 4, and output terminals 5a and 5b. And the ground terminal 6, and the insulating substrate 2 is sealed in the insulating case 1 with the resin 7.

As shown in FIG. 3, on the surface of the insulating substrate 2, variable resistors 8a and 8b, an input electrode 8c, and an output electrode 8 are provided.
d, 8e, connecting resistors 8f, 8g, 8h, ground electrode 8
i, center electrodes 8j and 8k are formed. Insulating substrate 2
At the position where the input electrode 8c and the ground electrode 8i of
Through holes 10a and 10b are formed, respectively.

Returning to FIG. 2, the conductive rubber 9a is pressed against the input electrode 8c, and the input terminal 4 is inserted into the conductive rubber 9a through the through hole 10a to be electrically connected to the input electrode 8c. . Similarly, the ground electrode 8i has a conductive rubber 9
The ground terminal 6 is connected via d and the through hole 10b. Further, conductive rubbers 9b and 9c are pressed against the output electrode 8d and the output electrode 8e, respectively.
The output terminals 5a and 5b are inserted into 9c, respectively, and are electrically connected. In the side sectional view shown in FIG. 2, the output terminal 5b is not shown because it overlaps the output terminal 5a. Furthermore, the variable resistor 8a and the center electrode 8j
Are electrically connected by the slider 3a, and the variable resistor 8b and the center electrode 8k are electrically connected by the slider 3b.

The high voltage input to the input terminal 4 of the high voltage variable resistor 30 is adjusted to a predetermined voltage by sliding the slider 3a attached to the rotating member 3 on the variable resistor 8a. Then, after being stepped down, it is output as a focus voltage from the output terminal 5a via the output electrode 8d and the conductive rubber 9b. Similarly, a screen voltage is output from the output terminal 5b which is inserted into the conductive rubber 9c which is pressed against the output voltage 8e.

Here, the conductive rubbers 9a, 9b, 9c, 9d
Is formed of a material having a low resistivity of 5 kΩ · cm or less, the voltage drop is mainly caused by the high voltage resistor.

[0008]

However, since a high voltage is applied to the high voltage resistor formed on the insulating substrate used in the conventional high voltage variable resistor 30, it is necessary to maintain good insulation. was there. Therefore, the shape of the high-voltage resistor formed on the insulating substrate is restricted. That is, if the space between the high-voltage resistors is widened to maintain insulation, the insulating substrate becomes large and the high-voltage variable resistor becomes large,
It was difficult to design a high voltage resistor having a complicated shape while keeping the insulating substrate small.

[0009]

Means for Solving the Problems The present invention has been made to solve the above problems, and has a rotation having an insulating substrate on which a high-voltage resistor is formed and a slider that slides on the high-voltage resistor. A member, an input terminal, an output terminal, and a ground terminal are housed in an insulating case, and at least one of the input terminal, the output terminal, and the ground terminal is electrically connected to the high-voltage resistor via a conductive rubber. In the connected high voltage variable resistor, the conductive rubber is formed of a material having a resistivity of 1.0 MΩ · cm or more.

[0010]

In the high-voltage variable resistor according to the present invention, the conductive rubber for connecting the input terminal and the output terminal to the high-voltage resistor is formed of a material having a high resistivity. A part of the resistance value of the high-voltage resistor formed can be secured by the resistance value of the conductive rubber. Therefore, since the voltage drop in the high-voltage resistor formed on the insulating substrate is small, the potential difference between the variable resistor and the connection resistor or the output electrode is small, so that the high-voltage resistor can be designed freely. The degree increases. That is, the insulating substrate can be downsized, and a high voltage variable resistor having various characteristics can be configured by using a standard insulating substrate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high voltage variable resistor 20 according to an embodiment of the present invention.
Will be described with reference to FIG. FIG. 1 is a partial sectional view of a high voltage variable resistor 20 of the present invention. Since the insulating substrate used in the high-voltage variable resistor 20 of the embodiment of the present invention is the same as that of the conventional example shown in FIG. 3, FIG. 3 will be used in the following description.

As shown in FIG. 1, a high voltage variable resistor 2
0 is the insulating case 1 and the variable resistors 8a, 8 shown in FIG.
b, the input electrode 8c, the output electrodes 8d and 8e, the connection resistors 8f, 8g and 8h, the ground electrode 8i, and the center electrode 8
an insulating substrate 2 on which j and 8k are formed, an input terminal 4, and
It has an output terminal (not shown) and a ground terminal (not shown).

The input terminal 4 and the input electrode 8c are electrically connected to each other by inserting the input terminal 4 into the conductive rubber 11 pressed against the input electrode 8c. Conductive rubber 1
Since 1 has elasticity, it can be inserted by simply inserting it.
Can be electrically connected to the input electrode 8c. An output terminal and an output electrode (not shown) or a ground terminal and a ground electrode are similarly connected by a conductive rubber.

The high voltage input from the input terminal 4 is the variable resistors 8a and 8b shown in FIG.
The voltage is stepped down by the conductive rubber 11 connected to the input electrode 8c or the ground electrode 8i, and is output from the output terminals 5a and 5b as a focus voltage or a screen voltage. The variable resistors 8a and 8b and the connection resistor 8g are cermet resistors formed by printing and firing a conductive paste containing ruthenium oxide as a main component. The conductive rubber 11 is made of a material in which carbon powder or metal powder such as Ag or Cu is dispersed in resin such as rubber,
For example, it has a high resistivity of 15 MΩ · cm. Therefore, the variable resistors 8a and 8b, the connection resistor 8g,
The conductive rubber 11 together functions to reduce the high voltage. That is, the high voltage is reduced by the variable resistors 8a and 8b and the connection resistor 8g, and the conductive rubber 11
Is also lowered by. Therefore, compared with the case where the resistance value of the conductive rubber 11 is low, the voltage stepped down by the variable resistors 8a and 8b and the connecting resistor 8g can be lowered. Therefore, the insulating substrate can be downsized, and the high-voltage variable resistor using the insulating substrate can be downsized.

When the conductive rubber 11 is used for the output electrodes 8d and 8e, the conductive rubber 11 functions as a protective resistor together with the connecting resistors 8f and 8h to limit the current flowing when the output is shorted. To do. Also in this case, the desired protection resistance value may be formed by the connection resistors 8f and 8h and the conductive rubber 11 in a shared manner, so that the substrate can be downsized.
Further, by combining an insulating substrate on which a standard high voltage resistor is formed and a conductive rubber having a different resistance value, it is possible to configure a high voltage variable resistor having different characteristics.
Since the conductive rubber only needs to function as a high voltage resistor,
Any number may be used as long as the resistivity is 1.0 MΩ · cm or more.

In this embodiment, the connection resistors 8f, 8g, 8h formed on the insulating substrate 2 are made of a material having a high resistivity and containing ruthenium oxide as a main component. However, silver or nickel is mainly used. It may be formed from a conductor as a component.

[0017]

According to the high voltage variable resistor of the present invention, the conductive rubber for connecting the input terminal or the output terminal and the high voltage resistor is made of a material having a resistivity of 1.0 MΩ · cm or more. The conductive rubber works together with the high-voltage resistor to cause a voltage drop. As a result, the voltage dropped by the high-voltage resistor formed on the insulating substrate can be reduced, so that the degree of freedom in designing the high-voltage resistor is increased. That is, the insulating substrate can be downsized, and a high voltage variable resistor having various characteristics can be configured by using a standard insulating substrate.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a high voltage variable resistor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional high voltage variable resistor.

FIG. 3 is a plan view of an insulating substrate which constitutes a conventional high voltage variable resistor according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation case 2 Insulation substrate 3 Rotating member 3a Slider 4 Input terminal 5a, 5b Output terminal 6 Grounding terminal 7 Resin 8a, 8b Variable resistor 8c Input electrode 8d, 8e Output electrode 8f, 8g, 8h Connection resistor 8i Ground electrode 8j, 8k Center electrode 9a, 9b, 9c, 9d, 11 Conductive rubber 20, 30 High voltage variable resistor

Claims (1)

[Claims] 1. An insulating substrate having a high-voltage resistor formed thereon, a rotating member having a slider that slides on the high-voltage resistor, an input terminal, an output terminal, and a ground terminal in an insulating case. In a high-voltage variable resistor that is housed and at least one of the input terminal, output terminal, and ground terminal is electrically connected to a high-voltage resistor through a conductive rubber, the conductive rubber is 1.0 MΩ · cm. A variable resistor for high voltage, which is formed of a material having the above resistivity.