JP7411212B2 - Resistance element for variable resistor - Google Patents

Description

The present invention relates to a resistance element for a variable resistor suitable for use in various variable resistors such as a rotary sensor.

Conventionally, as shown in FIG. 3 of Patent Document 1, for example, a variable resistor resistance element (variable resistor substrate) used in a rotary variable resistor has a ring-shaped current collection pattern (15) on the surface of a substrate (10). ) and an arc-shaped resistor pattern (16) surrounding the current collecting pattern (15), and three terminal connection patterns (50) are formed around one outer periphery of the substrate (10). Connect the connection pattern pulled out from the outer periphery of the electrical pattern (15) to the center terminal connection pattern (50), and connect the connection patterns pulled out from both ends of the resistor pattern (16) to the left and right terminal connection patterns (50), respectively. connected and configured. Each of these patterns is formed by screen printing or the like. Note that the current collecting pattern (15) and the resistor pattern (16) are sliding contact patterns on whose surfaces a slider made of a metal plate slides.

Japanese Patent Application Publication No. 10-172630

By the way, when it is desired to increase the electrically effective angle (rotation angle at which the slider can simultaneously slide on the current collecting pattern (15) and the resistor pattern (16)) in the resistance element for a variable resistor as described above, Both ends of the resistor pattern (16) must be extended to reduce the distance between them.

However, since the connection pattern drawn out from the current collecting pattern (15) passes between both ends of the resistor pattern (16), if the distance between both ends of the resistor pattern (16) is reduced as described above, the resistor pattern The distance between both ends of the current collecting pattern (16) and the connection pattern drawn out from the current collecting pattern (15) became narrow, and there was a possibility that ion migration would occur between the two.

The present invention has been made in view of the above points, and an object thereof is to provide a resistance element for a variable resistor that can effectively prevent ion migration.

The present invention provides an insulating substrate, a current collecting pattern for sliding contact formed on the insulating substrate, and a sliding contact sliding pattern formed so as to surround the outside of the current collecting pattern on the insulating substrate. a resistor pattern for contact, a terminal connection pattern for contacting metal terminals formed in three parallel locations at predetermined intervals on the insulating substrate, the current collection pattern and the center terminal connection pattern. and a connection pattern that connects each of the terminal connection patterns on both sides of the resistor pattern , and a connection pattern that connects each of the terminal connection patterns on both sides with the connection pattern on both sides . The central connection pattern is covered with a connection pattern coating layer made of the same carbon ink as the carbon ink forming the resistor pattern, and the central connection pattern is covered with an insulator layer. A concave portion is formed up to the top of the connection pattern covering portion covering the connection pattern, and further, a recess is formed on the side of the insulating layer opposite to each terminal connection pattern so as to form a gap from each terminal connection pattern. It is characterized by the fact that it has been established .
According to the present invention, since the exposed portion of the connection pattern is covered with the connection pattern coating layer (carbon layer), it is possible to prevent moisture from adhering to the connection pattern and prevent its ionization, thereby effectively preventing ion migration. It can be prevented.
In addition, since the same carbon ink as that forming the resistor pattern is used as the connection pattern coating layer, the resistor pattern and the connection pattern coating layer can be formed in the same process, improving work efficiency. Moreover, since the same material is used, cost reduction can also be achieved from this point of view.
In addition, when connection patterns connected to both ends of the resistor pattern are arranged on both sides of the connection pattern connected to the current collection pattern, as in the case of this resistance element for a variable resistor, all connection patterns have conductive connections. If a pattern coating layer is applied, the spacing between each connection pattern coating layer becomes narrower, increasing the risk of short-circuiting. However, according to the present invention, since the central connection pattern is covered with an insulating layer, there is no possibility of a short circuit between the connection patterns on both sides. It is possible to reliably prevent the possibility of short-circuiting.
Furthermore, since the insulating layer covering the central connection pattern is formed up to the connection pattern covering layer covering the connection patterns on both sides, ion migration between these connection patterns can be more effectively prevented.

In addition to the above-mentioned features, the present invention also provides a method in which a notch is formed between the adjacent terminal connection patterns of the insulating substrate, and a tip portion of a protruding portion between the recesses of the insulating layer is formed in the insulating substrate. It is characterized in that it is formed to a position that surrounds the innermost portion of the notch on the substrate .
According to the present invention, by providing the notch, migration between adjacent terminal connection patterns can be prevented. At the same time, the insulating layer can also prevent ion migration through the innermost portion of the notch.

According to the present invention, ion migration can be effectively prevented.

It is a top view of the resistance element 1 for variable resistors. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor substrate 1. FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor substrate 1. FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor substrate 1. FIG. FIG. 2 is an enlarged plan view of the main parts of the resistor substrate 1. FIG. 6 is a schematic partial cross-sectional view taken along the line AA in FIG. 5. FIG.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view of a resistance element for a variable resistor (hereinafter referred to as "resistance board") 1 according to an embodiment of the present invention. As shown in the figure, the resistance substrate 1 is a resistance substrate for a rotary variable resistor, and has a current collecting pattern 20, a resistor pattern 40, and three terminal connection patterns 60 (60- 1, 2, and 3). In the following description, "top" refers to the direction from which the side of the insulating substrate 10 is viewed from which various patterns such as the current collection pattern 20 are formed, and "bottom" refers to the opposite direction.

The insulating substrate 10 is made of a hard substrate made of synthetic resin such as polyphenylene sulfide (PPS) or nylon (PA). The shape of the insulating substrate 10 is approximately rectangular, with one side formed in an arc shape, the opposite side formed into a substantially linear terminal connection side 11, and a circular through hole in the center. There are 13. As described above, the current collecting pattern 20, the resistor pattern 40, and the like are formed by printing on the insulating substrate 10, and the structure thereof will be explained below along with the manufacturing method thereof.

2 to 4 are explanatory diagrams of the manufacturing method of the resistor board 1, in which figure (a) shows only the pattern printed in that process, and figure (b) shows the printed state of the patterns that have been overlapped up to that point. ing.

As shown in FIG. 2, first, by screen printing silver paste on the insulating substrate 10, the current collecting pattern main body 20A, three terminal connection patterns 60-1, 2, and 3, and each terminal connection pattern 60-1 are formed. Connection patterns 80-1, 2, and 3 connected to -1, 2, and 3 are formed.

The current collection pattern main body 20A is formed in a ring shape around the through hole 13 on the surface of the insulating substrate 10. The three terminal connection patterns 60-1, 2, and 3 are provided on the terminal connection side 11 on the surface of the insulating substrate 10 so as to be lined up at a predetermined interval. Furthermore, two notches 15-1 and 2 are formed in the terminal connection side 11 of the insulating substrate 10 so as to be recessed from the outer periphery, and these notches 15-1 and 2 are It is formed between adjacent terminal connection patterns 60-1, 2, and 3.

The central terminal connection pattern 60-2 is formed in a triangular shape whose width decreases toward the direction of the current collection pattern main body 20A. The distance between the terminal connection patterns 60-1 and 60-3 on both sides is widened. In addition, the terminal connection patterns 60-1 and 3 on both sides are formed into a substantially trapezoidal shape whose width decreases toward the direction of the current collecting pattern main body 20A. By making the notches 15-1 and 15-2 slope sides, the distance from the center terminal connection pattern 60-2 at the innermost portion of the cutout portions 15-1 and 15-2 (portion closer to the current collection pattern 20) is increased. By configuring the shape of each terminal connection pattern 60-1, 2, 3 as described above, ion migration (silver migration) at the innermost side of the notch portions 15-1, 2 is prevented.

A connection pattern 80-2 connected to the current collection pattern main body 20A is connected to the end of the central terminal connection pattern 60-2 on the current collection pattern main body 20A side. The connection pattern 80-2 is linear. Connection patterns 80-1 and 3, which are connected to both ends of the resistor pattern 40 described below, are connected to the ends of the left and right terminal connection patterns 60-1 and 60-3 on the collector pattern main body 20A side. The connection patterns 80-1 and 80-3 are formed in a shape that extends linearly in the direction of the central connection pattern 80-2, and then extends in a bent manner toward the current collecting pattern main body 20A side. The tip portions of the connection patterns 80-1 and 80-3 overlap with both end positions of the resistor pattern 40 described below.

Next, as shown in FIG. 3, carbon paste is screen printed on the insulating substrate 10 to form the current collecting pattern covering layer 20B, the resistor pattern 40, and the connecting pattern covering layers 80A-1 and 3. Form.

The current collecting pattern covering layer 20B is ring-shaped and has a width slightly larger than that of the current collecting pattern main body 20A so as to cover the entire surface of the current collecting pattern main body 20A. It is formed. The current collection pattern 20 is configured by the current collection pattern main body 20A and the current collection pattern covering layer 20B.

The resistor pattern 40 is formed in an arc shape so as to surround the outside of the current collecting pattern 20 at equal intervals. Connection pattern covering layers 80A-1 and 80A-3 are formed at both ends of the resistor pattern 40, respectively. One end of the connection pattern coating layer 80A-1, 3 is connected to the end of the resistor pattern 40, and after being pulled out toward the terminal connection side 11 side, the connection pattern coating layer 80A-1, 3 is connected to the left and right terminal connection pattern 60-1, 3 side. It is bent at a substantially right angle toward the direction and extended in a straight line. In other words, the connection pattern covering layers 80A-1, 3 are formed to cover the surfaces of the connection patterns 80-1, 3. Therefore, the width dimensions of the connection pattern covering layers 80A-1 and 80A-3 are formed to be slightly larger than the width dimensions of the connection patterns 80A-1 and 80A-3.

Next, as shown in FIG. 4, an insulating layer 100 is formed on the insulating substrate 10 by screen printing an insulating resin paste.

The insulating layer 100 is formed to cover the central connection pattern 80-2 and a pair of connection pattern covering layers 80A-1 and 80A-3 on both sides thereof. The insulating layer 100 has a substantially linear shape and is formed substantially parallel to the direction in which the terminal connection patterns 60-1, 2, and 3 are arranged. At the center of the insulating layer 100, a connection pattern insulating layer 101 is provided that protrudes in the direction of the current collection pattern 20 and covers the connection pattern 80-2. The connection pattern insulating layer 101 is formed to cover the entire connection pattern 80-2 (excluding the vicinity of the terminal connection pattern 60-2), and further covers both sides of the connection pattern insulating layer 101 in the width direction. is formed to have a width dimension that also covers the vicinity of the opposing inner sides of both connection pattern covering layers 80A-1 and 80A-3.

On the other hand, a portion of the lower side of the insulating layer 100 facing each of the terminal connection patterns 60-1, 2, and 3 is provided with recesses 103, 105 so as to form a predetermined gap from each of the terminal connection patterns 60-1, 2, and 3. , 107 are formed. Conversely, the portion between the recess 103 and the recess 105 and the portion between the recess 105 and the recess 107 on the lower side of the insulating layer 100 protrude downward, and their tip portions form the notch 15-1, respectively. . Through the above steps, the resistor substrate 1 is completed.

FIG. 5 is an enlarged plan view of a main portion of the resistor board 1 near the portion where the terminal connection patterns 60-1, 2, 3, etc. are formed. Further, FIG. 6 is a schematic partial cross-sectional view taken along the line AA in FIG. The resistor board 1 is housed in a mold (not shown) with one end of the metal terminal 120 in contact with each of the terminal connection patterns 60-1, 2, and 3, as shown by dotted lines in FIG. 6, for example. Then, by press-fitting and solidifying the molten resin into the cavity formed around the resistor board 1 in the mold and removing the mold, each metal terminal 120 is connected to each terminal connection pattern 60-1, 2, 3. Connect to. As a result, a case (not shown) in which the resistance board 1 and each metal terminal 120 are integrally fixed is formed. A rotary electronic component is assembled by incorporating a slider, a rotary knob, etc. onto the resistance board 1 installed in the case. When the slider is rotated, the sliding contact of the slider comes into sliding contact with the current collecting pattern 20 and the resistor pattern 40, and the electrical output between each metal terminal 120 changes.

As explained above, the resistance substrate 1 includes the insulating substrate 10, the resistor pattern 40 for sliding contact formed on the insulating substrate 10, and the resistor pattern 40 for sliding contact formed on the insulating substrate 10. a plurality of terminal connection patterns 60-1, 2, and 3 for contacting metal terminals formed on the insulating substrate 10, a resistor pattern 40, and any of the terminal connection patterns 60- 1 and 3, and between the current collecting pattern 20 and any other terminal connection pattern 60-2, the connection pattern 80-1, 2, and 3 are provided. At least a part of 80-1, 2, and 80-3 is covered with a connection pattern coating layer 80A-1, 3 made of the same carbon ink as that forming the resistor pattern 40.

With this configuration, the exposed portions of the connection patterns 80-1, 3 are covered with the connection pattern coating layer (carbon layer) 80A-1, 3, thereby preventing moisture from adhering to the connection patterns 80-1, 3. The ionization can be prevented, thereby effectively preventing ion migration. In particular, if the connection pattern coating layer (carbon layer) 80A-1, 3 is coated on at least a portion of the connection patterns 80-1, 3 that is close to another adjacent pattern, this portion, that is, the other adjacent pattern Ion migration can be prevented from the part closest to the pattern where short circuits due to ion migration are most likely to occur.

Furthermore, since the same carbon ink as that constituting the resistor pattern 40 is used as the connection pattern coating layers 80A-1, 3, the resistor pattern 40 and the connection pattern coating layers 80A-1, 3 are formed in the same process. This makes it possible to improve work efficiency, and since the same material is used, costs can also be reduced from this point of view.

By the way, the connection pattern covering layers 80A-1, 3 made of a carbon layer may not be able to completely cover the surfaces of the connection patterns 80-1, 3 due to pinholes or the like during printing. If there is a pinhole or the like, moisture will infiltrate through the pinhole and silver ions will be deposited from the silver patterns forming the connection patterns 80A-1 and 80A-3, but since the connection pattern coating layers 80A-1 and 3 have conductivity, The deposited silver ions move within the connection pattern covering layers 80A-1 and 3, causing ion migration. Therefore, in the resistance board 1, at least a portion of the connection pattern coating layers 80A-1 and 80A-3 (especially the portions where problems are likely to occur due to ion migration) is coated with an insulating layer 100. Silver patterns) 80A-1, 2, and 3 are further prevented from ionization and movement of silver ions, thereby effectively preventing ion migration.

In addition, since the resistance board 1 has the notches 15-1, 2 formed between the adjacent terminal connection patterns 60-1, 2, and 3 of the insulating board 10, can effectively prevent ion migration. At the same time, since a predetermined area including the innermost portions of the notches 15-1 and 15-2 on the insulating substrate 10 was covered with the insulator layer 100, the innermost portions of the notches 15-1 and 15-2 Ion migration along the portion can also be prevented by this insulator layer 100.

Further, in the resistor substrate 1, connection patterns 80-1 and 3 connected to both ends of the resistor pattern 40 are arranged on both sides of the connection pattern 80-2 connected to the current collecting pattern 20, and , 3 are coated with connection pattern covering layers 80A-1 and 80A-3, and the central connection pattern 80-2 is covered with an insulator layer 100 for the following reasons. That is, when the connection patterns 80-1 and 3 connected to both ends of the resistor pattern 40 are arranged on both sides of the connection pattern 80-2 connected to the current collecting pattern 20, all the connection patterns 80-1 and 2 , 3 are coated with a conductive connection pattern covering layer 80A, the distance between each connection pattern covering layer 80A becomes even narrower, increasing the risk of short circuits. Therefore, in the resistor board 1, the central connection pattern 80-2 is coated with the insulating layer 100, and as a result, compared to the case where the connection pattern 80-2 is coated with a conductive connection pattern coating layer, The electrical width dimension is not widened, thereby preventing the risk of short circuit with the connection patterns 80-1 and 80-3 on both sides.

Furthermore, in the resistor board 1, the insulating layer 100 covering the central connection pattern 80-2 is placed on the connection pattern covering layers 80A-1, 3 (parts thereof) covering the connection patterns 80-1, 3 on both sides. Since the ion migration prevention effect is even more effective, it is possible to obtain an even more effective ion migration prevention effect. Note that the sliding contacts of the slider need to be electrically connected on the connection pattern covering layers 80A-1, 3 directly above the ends of the connection patterns 80-1, 3, so the In this case, the connection pattern insulating layer 101 is not provided, and the connection pattern insulating layer 101 is formed near the opposing edges of both connection pattern covering layers 80A-1 and 80A-3 rather than on the corresponding portion.

In addition, in the above-mentioned resistance board 1, since the insulating layer 100 is provided with the recesses 103, 105, 107, even if printing misalignment occurs between the laminated patterns, the insulating layer 100 is There is no need to cover the top, thereby reliably preventing poor connection of metal terminals.

Further, as described above, a synthetic resin case is insert-molded around the resistor board 1, and a part of this case is also formed on the upper surface of the insulating layer 100 and the connection pattern coating layers 80A-1 and 3. By doing so, it is possible to more effectively prevent water from entering into the upper surface of the insulating layer 100 and the upper surfaces of the connection pattern covering layers 80A-1 and 3 on which the insulating layer 100 is not formed, resulting in a more effective migration prevention effect. can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings. It is possible. Note that any shape, structure, or material that is not directly described in the specification or drawings is within the scope of the technical idea of the present invention as long as it achieves the action and effect of the present invention. For example, in the above embodiment, an insulating substrate for a rotary variable resistor was described, but an insulating substrate for a sliding variable resistor in which a resistor pattern and a current collecting pattern are arranged linearly and parallel to each other, etc. The present invention can be similarly applied to insulating substrates for dexterity. Further, in the above embodiment, a rigid substrate made of synthetic resin is used as the insulating substrate, but a flexible substrate made of synthetic resin film may also be used. It goes without saying that various changes may be made to the shapes and materials of the resistor pattern, current collection pattern, terminal connection pattern, connection pattern, connection pattern coating layer, insulator layer, notch, etc. Furthermore, the embodiments described above and shown in the figures can be combined with each other as long as there is no contradiction in purpose, structure, etc. In addition, the above description and the contents of each figure, even if only a part thereof, can be an independent embodiment, and the embodiment of the present invention is an embodiment that combines the above description and each figure. It is not limited to.

1 Resistance board (resistance element for variable resistor)
10 Insulating substrate 15-1, 2 Notch portion 20 Current collection pattern 40 Resistor pattern 60 (60-1, 2, 3) Terminal connection pattern 80 (80-1, 2, 3) Connection pattern 80A (80A-1, 3) Connection pattern covering layer 100 insulator layer

Claims (2)

an insulating substrate;
a current collection pattern for sliding contact formed on the insulating substrate;
a resistor pattern for sliding contact formed so as to surround the outside of the current collecting pattern on the insulating substrate;
Terminal connection patterns for metal terminal contact formed in three parallel locations at predetermined intervals on the insulating substrate;
a connection pattern that connects between the current collecting pattern and the center terminal connection pattern , and between each of both ends of the resistor pattern and each of the terminal connection patterns on both sides;
In a resistance element for a variable resistor, comprising:
The connection patterns on both sides are covered with a connection pattern coating layer made of the same carbon ink as the carbon ink forming the resistor pattern , and the center connection pattern is covered with an insulating layer,
forming an insulating layer covering the central connection pattern up to a connection pattern covering portion covering the connection patterns on both sides;
The resistance element for a variable resistor is further characterized in that a recessed portion is provided on a side of the insulating layer opposite to each of the terminal connection patterns so as to form a gap from each of the terminal connection patterns . The resistance element for a variable resistor according to claim 1 ,
forming a notch between the adjacent terminal connection patterns of the insulating substrate;
A resistance element for a variable resistor, characterized in that a tip portion of a protruding portion between each of the recesses of the insulating layer is formed to a position that surrounds the innermost portion of the notch on the insulating substrate. .

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