JPH0334888Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] The present invention relates to a variable resistor such as a rotary type or a slide type, and is designed to prevent bad characteristics from occurring in the set resistance value, especially in the area where the resistor and electrode overlap. This invention relates to an improved variable resistor.

[Technical background]

Variable resistors include rotating types and sliding types, and in either case, a desired resistance value can be obtained by sliding a slider on a resistor. Therefore, it is desirable that the resistance value of the resistor increases proportionally from the starting end to the ending end.

[Prior art]

FIG. 4 is a plan view showing the main parts of a conventional variable resistor.

This variable resistor is of a rotating type, and a resistor 2 is formed on a substrate 1 on a circumference around a shaft hole 1a. Both ends of this resistor 2 are connected to an electrode 3. The resistor 2 and the electrode 3 are generally formed on the substrate 1 by printing.
In the process, electrodes 3 are first printed on the substrate 1,
Next, the resistor 2 is printed. At this time, both ends of the resistor 2 are overlapped on the electrode 3, as shown in FIG. 5 (enlarged view of section D in FIG. 4).

[Problems with conventional technology]

The electrode 3 is made of silver or the like, and the surface of the silver electrode 3 is as shown in FIG.
As shown in the cross-sectional view), the electrode 3 has an uneven shape.
It may be formed with raised edges. As a result, the thickness of the resistor 2 superimposed on the electrode 3 changes at each of points A, B, and C in FIG. 6. When the slider 21 (indicated by a dashed line) slides on the electrode 3 and the resistor 2, at points A, B, and C, the film thickness of the resistor 2 at the contact point of the slider 21 is the set resistance value. is proportional to. Therefore, if the film thickness of the resistor 2 changes as shown in FIG. 6, resistance will suddenly occur at position A while moving the slider 21, and resistance will suddenly occur between position A and position C. The resistance value increases and reverses from position B to position C. This resistance value change characteristic is shown in the resistance value Ra vs. rotation angle θ diagram in FIG. As a result of the resistance value characteristics shown in this diagram, when setting a small resistance value with a variable resistor, changes in characteristics such as the A, B, and C positions have a direct effect. Problems such as resistance value setting becoming unbalanced arise.

[Purpose of this invention]

The present invention has been made in view of the above-mentioned conventional problems, and aims to provide a variable resistor that eliminates the occurrence of adverse characteristics such as retrograde resistance in a small resistance value setting range.

[Structure of the present invention]

The variable resistor according to the present invention consists of an electrode attached to a substrate, a resistor attached to the substrate with its end overlapped with the electrode, and a slider that slides on the electrode and the resistor. , a notch through which the electrode is exposed is formed at the end of the resistor, and the slider has a portion that slides on the overlapping portion of the electrode and the resistor, and a portion that passes through the notch. It is formed by forming a part that

In the above means, when the slider moves from the electrode to the resistor, a part of the slider slides on the overlap between the electrode and the resistor, and the other part slides on the overlap between the electrode and the resistor. It short-circuits with the electrode within the notch without passing through the section, and then moves to the resistor. Therefore, variations in the resistance value due to changes in film thickness at the overlapping portion of the electrode and the resistor hardly occur.

[Example of the present invention]

Embodiments of the present invention will be described below with reference to the drawings of FIGS. 1 to 3.

Figure 1 is an enlarged view showing the main parts of the variable resistor, Figure 2
The figure is an enlarged view of section E in FIG. 1, and FIG. 3 is a diagram showing resistance value change characteristics of a variable resistor. Note that the drawings only show the characteristic parts of the present invention.

[Configuration of Example]

Reference numeral 1 in the figure is a substrate. A shaft hole 1a is bored in the center of this substrate 1. An operating shaft (not shown) is inserted through the shaft hole 1a, and a slider 21 (shown by a chain line) is fixed to this operating shaft. On the surface of this substrate 1, resistors 20 are formed by printing, positioned on the circumference around the shaft hole 1a. This resistor 20 is made of carbon or the like. The shape of the resistor 20 on the circumference is almost the same as that shown in FIG.

The end of this resistor 20 is connected to the electrode 3. The electrode 3 is made of silver and is formed on the substrate 1 by printing. A metal terminal of a variable resistor is fixed to this electrode 3.

The end portion 20a of the resistor 20 is formed into a comb-teeth shape. As shown in FIG. 2, a plurality of (two in the figure) U-shaped grooves 20c are formed between the comb-like end portions 20a. This end 20
As a result of overprinting a on the electrode 3, the electrode 3 is exposed within the U-shaped groove 20c. Note that an air space α is provided between the edge 3a of the electrode 3 and the bottom of the U-shaped groove 20c.

In FIG. 2, reference numeral 21a indicates a contact point formed on the slider 21. As shown in FIG. This contact point 21
A is a slider 21 made of a thin metal plate whose tip is divided into pieces to have elasticity, and seven pieces are formed in the figure. Of these, two are desired for each U-shaped groove 20c of the resistor 20.

(Operation of the embodiment) Next, the operation of the variable resistor having the above configuration will be explained. In the resistance value change characteristic diagram shown in FIG. 3, the resistance value characteristics are expressed with the vertical axis representing the resistance value Ra (%) and the horizontal axis representing the rotation angle θ (rad) of the slider.

At the initial position, the contact 21a of the slider 21, which rotates around the shaft hole 1a, is in contact with the electrode 3. The resistance value in this state is zero. From here, when the slider 21 is gradually rotated counterclockwise, a portion of the contact 21a comes into contact with the comb-shaped end 20a of the resistor 20 (position A). However, in this state, the other contact 21a faces the U-shaped groove 20c and is sliding on the electrode 3, so the current concentrates on the other contact 21a, so no resistance occurs. .

Then, this slider 21 touches the edge 3a of the electrode 3.
When the contact point 21a in the U-shaped groove 20c is separated from the electrode 3, it faces the space α (position F). Therefore, the resistance value is set from this F position (see FIG. 3). Incidentally, since the resistance value was zero up to this F position, there is no occurrence of a change in resistance value as in the conventional characteristic shown in FIG.

When the slider 21 is further rotated, the resistor 20
When the resistance value set by the contacts 21a in contact with the end 20a of From there it rises proportionally or according to a set curve.

(Application example) The variable resistor according to the present invention can also be applied to a slide type.

[Effects of this invention]

As described above, according to the present invention, in the overlapping part between the electrode and the end of the resistor, the end of the resistor has
A notch is formed to separate from the electrode, and a portion of the slider slides on the overlapping portion, and the other portion short-circuits with the electrode within the notch and then moves to the resistor. Therefore, unlike in the prior art, changes in the film thickness of the resistor in the overprinted portion do not have an adverse effect on the setting of the resistance value, and characteristics such as retrograde resistance as shown in FIG. 7 do not occur. Therefore, the resistance value can be set in a well-balanced manner in the small resistance value setting region.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a plan view showing the main parts of the variable resistor, Figure 2 being an enlarged view of section E in Figure 1, and Figure 3 being an enlarged view of section E in Figure 1. is a diagram showing resistance value change characteristics, Figure 4 and the following diagrams show conventional examples, Figure 4 is a plan view of a variable resistor, Figure 5 is an enlarged view of section D in Figure 4, and Figure 6. 5 is a cross-sectional view taken from FIG. 5, and FIG. 7 is a diagram showing resistance value change characteristics. 1...Substrate, 3...Electrode. 20...Resistor, 2
0a... end of comb teeth, 21... slider, 21a...
...Contact point of slider.

Claims (1)

[Scope of utility model registration request] It consists of an electrode attached to a substrate, a resistor attached to the substrate with its end overlapped with the electrode, and a slider that slides on the electrode and the resistor,
A notch through which the electrode is exposed is formed at the end of the resistor, and the slider has a portion that slides on the overlapping portion of the electrode and the resistor, and a portion that passes through the notch. A variable resistor consisting of a portion.