JPH0864402A - Thin film resistor - Google Patents

Abstract

PURPOSE: To enable further free and easy selection of a resistance value of a thin resistor formed by using a resistance material such as a film type, a sheet type and a thin plate type material. CONSTITUTION: The title resistor is formed by forming electrodes 2a, 2b in opposed two surfaces which are vertical to a thickness direction of a thin film resistance material 1 and an area of a conductor part of at least one of the electrodes 2a, 2b in contact with a thin film resistance material 1 is smaller than that of the opposed two surfaces. An electrode in such a thin film resistor can be arranged to make just a part thereof overlap each other. At least one of the electrodes can be formed by providing a dotted or linear electrode conductor-free part or can be formed put on an insulator or a high resistance conductor with an area which is smaller than that of an electrode. An electrode of a thin film resistor can be also formed by overlaying at least two striped conductor patterns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor used in an electric circuit, in which electrodes are provided on both sides of a thin film resistance material, and a current flows in the thickness direction of the thin film resistance material. Regarding

[0002]

2. Description of the Related Art Most of resistors used in conventional electric circuits are of a type in which a current flows in a direction along a surface of the resistor as represented by a planar type. The most commonly used carbon film resistor is a typical example. On the other hand, as a typical example of a sandwich type resistor in which a current flows in the thickness direction of the resistor, there is a PTC thermistor.

FIG. 9 schematically shows a conventional example of a general thin film resistor. As shown in the figure, a sheet-shaped resistance material 1
Electrodes 2a and 2b are formed on the upper and lower surfaces of the above. The same applies to the case where the thin plate resistance material 1 has a sheet shape or a film shape. Each of these electrodes is connected to an external electric circuit (not shown). Here, if the external dimensions of the resistor are defined, the resistance value R is the thickness t of the resistor material,
Let S be the electrode area and ρ be the volume resistivity of the resistive material, then R
= Ρ (t / S).

FIG. 10 shows a thin film resistor in which the resistance material is made thinner and the resistance value is set smaller than that of the thin film resistor shown in FIG. As shown in FIGS. 9 and 10, conventionally, electrodes are provided over the entire upper and lower surfaces of the plate-shaped resistance material 1.

In the resistors used in these electric circuits, the resistance value is set and adjusted by changing the volume resistivity of the material or by substantially changing the vertical and horizontal dimensions of the resistors by slits or the like. On the other hand, in the case of a resistor having a structure in which current flows in the thickness direction of a thin film resistance material such as a film or sheet, it is impossible to change the volume resistivity of the material freely because of the unique characteristics of the material, However, it is difficult to change the size of the resistor, and it is often impossible to change the size of the resistor due to the limitation of the outer shape. Therefore, there has been virtually no method for freely changing the resistance value.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention, in particular, to allow the resistance value of a thin resistor sandwiched by plane electrodes to be freely selected.

[0007]

Means for Solving the Problems When the present inventors form a thin resistor in which a current flows in the thickness direction by using a resistive material such as a film, a sheet, or a thin plate, the thickness of the material, By changing the effective resistivity of the upper and lower electrodes in combination with changing the resistivity, it has been conceived that an arbitrary resistance value can be selected more freely.

According to the present invention, electrodes are formed on two opposing surfaces of the thin film resistance material which are perpendicular to the thickness direction,
There is provided a thin film resistor in which at least one conductor portion of the electrode, which is in contact with the thin film resistor material, has an area smaller than the area of the two opposing surfaces. The electrodes in such a thin film resistor can be arranged such that only some of these electrodes overlap. Further, at least one of the electrodes can be provided with a portion without a dot-shaped or linear electrode conductor. The part without the electrode conductor can also be formed by spraying a conductor having a coarse grain size. Further, at least one of the electrodes can be formed by being stacked on an insulator or a high resistance conductor which has an area smaller than that of the electrode and which is placed on the thin film resistance material. The electrode of the thin film resistor of the present invention may be formed by stacking a striped conductor pattern formed by arranging a plurality of elongated strip-shaped conductor portions substantially in parallel at least twice.

Further, according to the present invention, it has a structure in which a plurality of thin film resistance materials are stacked, and an electrode provided on an outer surface perpendicular to the thickness direction of the thin film resistance material and an electrode provided between the thin film resistance materials. Is provided, wherein the area of at least one of the conductor portions in contact with the thin film resistance material is smaller than the area of the thin film resistance material. By combining the resistors in this way, there is an advantage that a wider resistance range can be set. Moreover, a thin film resistor having a desired thickness can be formed by using a resistor material having a constant thickness.

Further, according to the present invention, at least one of two opposing surfaces perpendicular to the thickness direction of the thin film resistance material is provided with two or more electrodes spaced apart by a distance larger than the thickness of the thin film resistance material and facing each other. There is provided a thin-film resistor having a structure in which a plurality of resistance elements each including two electrodes are connected in series. By adopting such a configuration, it is possible to substantially form a plurality of resistors within the thickness of one resistor, and by connecting these resistors in series, a wider resistance range can be obtained. Can be set. Therefore, there is an advantage that the degree of freedom in selecting the resistance value is improved.

By adopting the above structure, it is possible to easily realize the target resistance value in the thin film resistor using a thin material, which has many restrictions in terms of material. By forming electrodes on the upper and lower surfaces of a film-shaped thin resistance material and freely adjusting the resistance value, a small resistor can be realized. When trying to form a pattern on such a thin resistance material itself, very fine punching is required,
Depending on the material and the resistance value, it may be difficult to set an arbitrary resistance value, but according to the present invention, such pattern processing is unnecessary and a small resistor can be easily formed.
Various functions that can be realized by applying the resistor of the present invention will be described in detail with reference to the following examples.

The thin film resistance material of the present invention has a film shape, a sheet shape, a thin plate shape, or the like. Also,
The above-mentioned resistance material may be a thin shape or a material that can be thinly processed, and it is a conductive polymer such as polyacene, polyaniline, polypyrrole, or polythiophene, or polyester in which fine particles such as carbon are dispersed. Polymers such as polyimide, polyether / sulfone, polyether / ether / ketone, molybdenum silicide, ruthenium oxide, and oxide semiconductor ceramics such as barium titanate as a PTC material can be used. Further, the electrodes can be formed by a printing method of printing a paste-like material such as silver paste or copper paste, and can also be formed by a chemical plating method. Further, it can be formed by a physical vapor deposition method for fixing the metal evaporated in a vacuum or a thermal spraying method using a molten metal powder or the like. Further, the insulator used in the present invention is not particularly limited, but there is, for example, a polyimide-based synthetic resin.

[0013]

1 to 8 schematically show a preferred embodiment of the present invention. In these drawings, the vertical and horizontal scales are not necessarily the same in order to facilitate understanding of the invention. These examples will be described in comparison with the configuration examples of the general thin film resistors of FIGS. 9 and 10.

FIG. 1 schematically shows a first embodiment of the present invention. As shown in FIGS. 9 and 10, the thin film resistor of each embodiment of the present invention comprises a thin film resistor material 1 and electrodes 2a and 2b provided on the upper and lower surfaces thereof, respectively. As in the conventional example, the thin resistance material 1 may be in the form of a sheet or a film. These electrodes 2a, 2
Each b is connected to an external electric circuit (not shown).

As shown, the upper and lower electrodes 2a,
The areas of 2b are different. That is, the area of the upper electrode 2a is smaller than that of the lower electrode 2b. By changing the size of the electrode in this way, the size of the portion of the resistor that actually functions as the electrical resistance becomes smaller and the resistance value increases. Further, if the smaller electrode 2a is formed with high accuracy, an accurate resistance value can be obtained even if the area accuracy of the whole thin film resistor is not so high. Example 2 of the present invention is shown in FIG. Here, by changing the positions of the electrodes 2a and 2b formed on the resistance material and changing the overlapping area, it is possible to reduce the size of the resistance material portion functioning as a resistance and set the resistance value to a large value. it can.
Example 3 is shown in FIGS. Here, the electrode 2a formed on the resistance material is provided with a plurality of portions 3 having no point-like conductor to reduce the effective electrode area, thereby increasing the resistance value without changing the size of the entire resistor. Can be set to a value. In order to reduce the effective area of the electrode in this way, when the electrode is formed by the thermal spraying method, for example, nickel alloy, stainless alloy, cobalt alloy, aluminum, or a semiconductor such as ZnO or alumina, MgO or the like is used. , Spinel, mullite,
This can be achieved by enlarging the particles of the electrode material such as a mixture of insulating powder such as zirconia. FIG. 4 shows an example of an electrode pattern that can be used in the third embodiment.

FIG. 5 shows a fourth embodiment. Here, a striped conductor pattern formed by arranging a plurality of elongated strip-shaped conductor portions substantially in parallel is formed at least twice. When the electrodes are formed by overlapping the striped conductor patterns 4a and 4b, the overlapping area can be changed by changing the direction of the stripes, and the effective area of the electrodes can be changed and adjusted. . The number of times the conductor patterns are superposed is two in the present embodiment, but three or more conductor patterns can be superposed. The conductor patterns to be overlapped may be the same or different. Example 5 is shown in FIG. Here, first, an island-shaped non-conductor pattern is formed on the surface of the resistance material, and an electrode conductor is formed on the non-conductor pattern. In FIG. 6 (a),
An island-shaped non-conductor pattern 5 is formed on the resistance material. FIG. 6B shows a state in which the electrode conductor formed thereon covers the non-conductor pattern. As in the third embodiment, the effective electrode area can be reduced, so that the resistance value can be increased without changing the size of the entire resistor.

In the above-mentioned embodiments, depending on the material and structure of the electrode, after forming the electrode, it is possible to form a small dot-shaped or linear cut-out portion on the electrode by laser or the like. Thereby, the resistance value can be adjusted after the electrodes are formed.

Embodiment 6 is shown in FIG. Here, the resistance materials 11a and 11b are laminated in two layers, and the upper layer 11a
Is smaller than the lower layer 11b. Electrodes 12 are formed on the upper surface of the upper resistance material and the lower surface of the lower resistance material.
In addition to a and 12b, an electrode 13 made of a conductor is also provided between the two layers of resistance material. By adopting such a configuration, there is an effect that a plurality of resistors are combined and a wider resistance range can be set. These electrodes 12a, 12b, 13 can be formed in the same manner as in the above-described first to fifth embodiments. Also,
Preferably, the electrode 13 sandwiched between the two layers of resistance materials 11a and 11b diffuses Joule heat generated in each resistance material and prevents a local temperature rise.
It is formed so as to be in close contact with the surfaces of the two layers of resistance material. The number of laminated resistance materials is not limited to two, and may be three or more as required.

FIG. 8 shows a seventh embodiment. Here, the wide first electrode 2 is formed on one surface (lower surface in the figure) of the resistance material 21.
2 is provided, and the second and third electrodes 23 and 24 are separated from each other at a sufficiently large interval as compared with the thickness of the resistance material 21, for example, at an interval of about twice the thickness or more. It is formed on the upper surface in the figure). By adopting such a configuration, between the second electrode 23 and the first electrode 22 and the first electrode
Resistor elements are formed between the electrode 22 and the third electrode 24, and these resistor elements are connected in series by the first electrode 22 to form one resistor. By adopting such a configuration, there is an advantage that a plurality of resistors can be formed within a thickness of one resistor unit and a wider resistance range can be set. By connecting a lead wire (not shown) to the second electrode 23 and the third electrode 24, it is possible to connect to an external circuit and also to connect a lead wire to the first electrode 22 to obtain different resistance values. it can. It is preferable to adopt the electrodes of Examples 3 to 5 as each electrode in this example. Arrows 25 and 26 indicate an example of the direction of current flow. Although not shown, by combining Examples 6 and 7, it is possible to integrate a plurality of elements on a planar substrate or the like while adjusting the resistance value.

[0020]

As described above, according to the present invention, a small resistor can be realized by forming electrodes above and below a film-shaped thin resistance material and freely adjusting the resistance value. The patterning of the resistance material itself, which requires punching, becomes unnecessary, and it becomes easy to form a small resistor with few restrictions on the material and the resistance value.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of a thin film resistor of the present invention.

FIG. 2 is a schematic perspective view showing a second embodiment of the thin film resistor of the present invention.

FIG. 3 is a schematic perspective view showing Example 3 of the thin film resistor of the invention.

FIG. 4 shows an example of electrodes that can be used in the thin film resistor of FIG.

FIG. 5 is a schematic perspective view showing a fourth embodiment of the thin film resistor of the present invention.

FIG. 6 is a perspective view showing a fifth embodiment of the thin film resistor of the present invention.

FIG. 7 is a perspective view showing a sixth embodiment of the thin film resistor of the present invention.

FIG. 8 is a perspective view showing Example 7 of the thin film resistor of the invention.

FIG. 9 is a perspective view showing an example of a conventional thin film resistor.

10 is a perspective view showing a modification of the conventional thin film resistor of FIG.

[Explanation of reference numerals] 1 resistors 2a, 2b electrodes 3 portions without conductors 4a, 4b conductor patterns 11a, 11b resistance material 12a, 12b, 13 electrodes 21 resistance material 22 first electrode 23 second electrode 24 third electrode 25, 26 Direction of current

Claims (16)

[Claims] 1. An electrode is formed on each of two opposing surfaces of the thin film resistance material which are perpendicular to the thickness direction, and the area of at least one of the electrodes, which is in contact with the thin film resistance material, has an area of A thin film resistor that is smaller than the area of two opposing surfaces. 2. The thin film resistor according to claim 1, wherein the electrodes are arranged so that only a part of the electrodes overlap each other. 3. The thin film resistor according to claim 1, wherein at least one of the electrodes is provided with a portion having no dot-shaped or linear electrode conductor. 4. The thin film resistor according to claim 3, wherein the portion without the electrode conductor is formed by spraying a conductor having a coarse grain size. 5. At least one of the electrodes is formed overlying an insulator having an area smaller than that of the electrode or a conductor having a resistance value higher than that of the thin film resistance material, which is placed on the thin film resistance material. The thin film resistor according to claim 1, wherein 6. The electrode according to claim 1, wherein at least one of the electrodes has a striped conductor pattern formed by arranging a plurality of elongated strip-shaped conductor portions substantially parallel to each other at least twice. Thin film resistor. 7. An electrode having a structure in which a plurality of thin film resistance materials are stacked, and at least one of an electrode on an outer surface perpendicular to the thickness direction of the thin film resistance material and an electrode provided between the thin film resistance materials. 1. A thin film resistor, wherein the area of a conductor portion in contact with the thin film resistance material is smaller than the area of the thin film resistance material. 8. A thin film resistance material is provided with two or more electrodes at least one of two facing surfaces perpendicular to the thickness direction at a distance larger than the thickness of the thin film resistance material. A thin film resistor having a configuration in which a plurality of configured resistance elements are connected in series. 9. The thin film resistor according to claim 1, wherein the thin film resistor material is a polymer having conductivity. 10. The thin film resistor according to claim 1, wherein the thin film resistor material is a polymer in which conductive fine particles are dispersed. 11. The thin film resistor according to claim 1, wherein the thin film resistor material is made of at least one kind of electrically conductive ceramic. 12. The thin film resistor according to claim 1, wherein the electrode is formed by a printing method. 13. The thin film resistor according to claim 1, wherein the electrode is formed by a plating method. 14. The thin film resistor according to claim 1, wherein the electrode is formed by a thermal spraying method. 15. The thin film resistor according to claim 1, wherein the electrode is formed by a vapor deposition method. 16. The thin film resistor according to claim 1, wherein the thin film resistor is manufactured by adjusting a resistance value by forming a missing portion after forming the electrode.