JP2844640B2 - Variable resistance element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable resistance element.

[Conventional technology]

 FIG. 3 is a plan view of an example of a conventional variable resistance element.

Carbon, metal, as an electric resistance material on an insulating substrate
The thin film resistor 11 made of a metal oxide or a mixture thereof is formed in an arc shape by using various methods such as printing, plating, vapor deposition, and sputtering. At the end of the thin film resistor 11, a lead 17 and an electrode 12 for external connection are attached. A brush 13 made of metal is provided as a third electrode for obtaining a variable resistance so as to maintain contact with the thin film resistor 11. To move the position of the brush with respect to the resistor, a knob 14 is attached and connected to the brush 13. Usually, the knob has a structure in which a spacer 15 made of Teflon or the like is interposed between the knob and the brush to provide some electrical insulation to the brush. Mounting pedestal 16
And a cover (not shown).

[Problems to be solved by the invention]

The conventional variable resistor has a problem that undesired noise is generated due to contact between the brush, which is the third electrode of the variable resistance element, and the thin film resistor, especially when a minute voltage or current is handled. Was. This noise is considered to occur because the brush and the thin-film resistor are merely pressed mechanically and are in contact with each other, and there is no strong connection such as joining by alloying of the contact metals. In particular, the brush and the thin-film resistor where the contact actually occurs are usually used in a state where the surface is not protected at all. In a place where an alkali is present, there is a problem that the reliability of the resistance element becomes extremely low.

Furthermore, when placed in the above environment, brush,
When an insulating layer such as an oxide film is generated on the surface of the thin film resistor and the brush is moved by turning or moving the knob to change the resistance value, in the case of an audio device, a large contact failure such as rattling occurs. There was also a problem that noise was generated.

[Means for solving the problem]

The variable resistance element of the present invention has at least one magnetoresistance element provided on an insulator substrate and a magnet for applying a magnetic field to the magnetoresistance element, and the magnet has a distance from the surface of the insulation substrate. It is characterized by being supported vertically variable.

The variable resistance element according to the present invention may further include an insulating substrate, at least one magnetoresistive element provided on a surface of the substrate at a predetermined distance from a center of the substrate, and both ends of the magnetoresistive element. At least one set of two leads connected to the external lead-out terminal and a cover for covering the surface of the substrate including the magnetoresistive element, and the cover so that the center is aligned with the center of the substrate. It is configured to include an inscribed screw hole, a screw screwed into the screw hole, and a magnet provided at the tip of the screw.

[Action]

Semiconductors such as silicon have a general property of a magnetoresistance effect in which the electric resistance changes when a magnetic field is applied. This effect is due to the spatial modulation of the concentration under the influence of the magnetic field in which electrons and holes, which are the carriers of current in silicon, are applied. It is described as being caused by the change. The magnetoresistance effect shows a large value when the impurity concentration is low. However, since a resistor having a large piezoresistive effect changes its sensitivity sensitively to a change in temperature, it is usually used after performing some kind of temperature correction. Since the change in resistivity to magnetism is very linear, there is a characteristic that the amount of magnetism can be accurately converted in proportion to the change in electric resistance.

The above-mentioned sensor aims to dynamically convert an external dynamic signal into an electric signal, but temporarily or permanently converts a once applied physical signal into a temporarily or permanently fixed signal. By newly adding a structure for fixing to a value, it can be used as a variable resistance element or a semi-fixed resistance element.

〔Example〕

1 (a) and 1 (b) are a front view and a sectional view taken along line AA 'of a first embodiment of the present invention.

The magnetoresistive element 1 is provided at a position slightly away from the center of the surface of the insulating substrate 7. The terminals 5 attached to the substrate 7 and both ends of the magnetoresistive element 1 are connected by leads 8. A cover 4 having a screw hole in the center is covered and fixed. The screw 3 with the magnet 2 attached to the tip is inserted into the screw hole of the cover 4.
The resistance value of the magnetoresistive element 1 changes according to the magnetic field generated by the magnet 2. Therefore, by changing the position of the magnet 2 by turning the screw 3, the resistance value of the magnetoresistive element 1 can be adjusted to a desired value, and the variable resistance element of the present invention can be obtained.

The electric resistance value of the variable resistance element depends on the concentration of impurities used when manufacturing the magnetoresistance element. Since the magnetoresistance effect and the temperature coefficient of the resistance value also change as a function of the impurity concentration, these values are adjusted to the required values and used. Here, even if the impurity concentration is the same, it is possible to provide an electric resistance value suitable for an arbitrary application by increasing or decreasing the width and depth of the magnetoresistive element or changing the length. The adjustment of the electric resistance value is performed by changing the distance between the magnet provided at the tip of the screw and the magnetoresistive element by turning the screw. The variable range of the electric resistance value can be changed to the vicinity not in contact with the resistive resistance element by adjusting the moving amount of the magnet. Therefore, it is necessary to restrict the movement of the screw, and some stopper may be provided. The size and shape of the screw are arbitrary, and any effect other than the screw can be used as long as it has a function of stopping the application of an appropriate magnetic field to the magnetoresistive element.

 FIG. 2 is a sectional view of a second embodiment of the present invention.

In this embodiment, four magnetoresistive elements 1 are provided at the same distance from the center of the surface of the insulating substrate 7 so that the plurality of magnetoresistive elements receive the same magnetic field. Leads 8 are connected to both ends of 1 and terminals 5. Although not shown, the same cover and magnet screw as in the first embodiment are attached.

By adopting such a configuration, it is possible to change many resistance elements at once. Such a variable resistance element is very convenient as a collective variable resistor in a device having multi-channel input / output.

In the above-described embodiment, the case where only the magnetoresistive effect is used has been described. However, the same effect can be expected even when an element such as a magnetic transistor is used as the magneto-resistance converting element. In this case, it can be used as a large variable resistance element that cannot be obtained only with the magnetoresistance effect element.

〔The invention's effect〕

If the variable resistance element of the present invention is used, a new noise due to contact, which was a problem in the conventional variable resistor, or abnormal noise due to poor contact, the brush and the thin film resistance element can be made of different materials. It is possible to solve the problem that the S / N ratio is lowered due to generation of various noises such as drift due to the generation of thermoelectricity.

Further, conventionally, various methods have been used to reduce the contact resistance. However, since the device is used in a state where the device is not in contact with the resistor, it is cheap and reliable without such a method. High variable low antibodies are obtained. Since the magnetoresistive element can be manufactured by a semiconductor manufacturing process, it can be easily mass-produced, and a stable quality can be obtained. Conventionally, the surface of the brush or thin-film resistance of the variable resistor, which was exposed in the past, does not exist, and the surface of the magnetoresistive element can be sufficiently protected. However, according to the present invention, passivation for an arbitrary environment can be easily performed only by changing the thin film provided on the surface of the magnetoresistive element. Conventionally, there has been a pseudo-continuous attenuator using an analog switch by a digital method,
Since a large-scale circuit is required to control the continuously changing electric resistance, it is impossible to realize the function as a single component. In the present invention, individual components can be installed without taking up space.

[Brief description of the drawings]

1 (a) and 1 (b) are a front view and a sectional view taken along line AA 'of the first embodiment of the present invention, FIG. 2 is a sectional view of the second embodiment of the present invention, and FIG. FIG. 2 is a plan view of an example of a conventional variable resistance element. 1 ... Magnetic resistance element, 2 ... Magnet, 3 ... Screw, 4 ...
Cover, 5 ... Terminal, 7 ... Substrate, 8 ... Lead, 11 ...
... thin film resistor, 12 ... electrode, 13 ... brush, 14 ... knob, 15 ... spacer, 16 ... shooting base, 17 ... lead.

Claims (2)

(57) [Claims] 1. A semiconductor device comprising: at least one magnetoresistive element provided on an insulator substrate; and a magnet for applying a magnetic field to the magnetoresistive element. A variable resistance element characterized in that it is supported in such a manner that: 2. An insulating substrate, at least one magnetoresistive element provided on a surface of the substrate at a predetermined distance from the center of the substrate, and externally connected to both ends of the magnetoresistive element. At least one set of two leads to be connected to the terminal, a cover covering the substrate surface including the magnetoresistive element, and a screw cut into the cover so that the center is aligned with the center of the substrate. A variable resistance element comprising: a hole; a screw screwed into the screw hole; and a magnet provided at a tip of the screw.