JPS6355848B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a variable resistor.

As shown in FIG. 1, the basic configuration of a variable resistor is that a film-like current collector 2 and a film-like resistor 3 are arranged side by side on a substrate 1. The resistance value is changed by the movement of the slider 4 that slides on the .

The relationship between the amount of slider movement and the resistance value of this variable resistor is divided into two types: one having a characteristic as shown by a straight line A in FIG. 2, and the other having a characteristic as shown by a curve B in FIG. The present invention is directed to a variable resistor having characteristics as shown by curve B.

FIG. 3 shows the state of the resistor 3 in a conventional variable resistor having characteristics as shown by curve B. As shown in this figure, in the conventional method, the thickness of the resistor 3 is changed stepwise by overcoating, and the resistance value is changed non-linearly in response to the change.

However, the method for manufacturing the resistor 3 described above is
Apply the first layer of resistor paste on the board 1, then apply the second layer on top of the first layer, the third layer on top of the second layer, the fourth layer on top of the second layer, etc. with varying lengths. In this method, the resistor paste layers are made thicker from one end to the other, which results in poor workability in manufacturing the resistor 3 and also creates steps between each layer. Due to the presence of this step, the sliding movement of the slider is not smooth, and although characteristics such as curve B in Fig. 2 could originally be obtained, a step appears in the characteristic curve at the step portion. A smooth resistance value change cannot be obtained.

An object of the present invention is to provide a variable resistor that is easy to manufacture, allows smooth movement of a slider, and has good resistance value change characteristics, without the drawbacks of the prior art as described above.

In order to achieve this object, the present invention forms dot-shaped first resistance parts having different areas and intervals on the surface of a substrate, and on top of the first resistance parts, a first resistance part with an electrical resistance value of This is characterized in that the second resistance portion is formed in a different continuous layered manner.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 4 is a plan view of the screen used in the present invention, FIGS. 5 and 6 are partial plan views and cross-sectional views of a resistor substrate in which the first resistor part is formed using the screen, and FIG. FIG. 2 is a partial cross-sectional view of a resistor substrate in which a second resistor portion is formed on a first resistor portion.

On the surface of the insulating substrate 21 made of a ceramic plate, glass plate, synthetic resin plate, etc., and on both sides of the area where the later-described resistive layer is to be formed, a conductive paste is applied by screen printing as shown in FIG. Conductive portions 22, 22 are formed thereon.

Next, the conductive portion 22,
The first resistor section 23 is formed between 22,
The screen 24 used at this time has a hole pattern as shown in FIG. That is, the screen 24 has a large number of rectangular through holes 25 lined up, but the through hole area 2
As shown in 6A to 26G, the area of the through holes 25 gradually increases from one end to the other, and the distance between the through holes 25 gradually narrows, so that each through hole The aperture ratio gradually differs in the perforated regions 26A to 26G.

A state in which the first resistance section 23 is formed on the insulating substrate 21 using this screen 24 is shown in FIGS. 5 and 6. Since the screen 24 has the above-mentioned through-hole pattern, the dot-shaped and generally band-shaped first holes are formed accordingly.
The resistance portion 23 includes resistance portion formation regions 27A to 27G.
(See FIG. 5), the formation area of the first resistance portion 23 per unit area gradually differs. This first resistor section 23 is formed using a resistive paste having a relatively high electrical resistance value in order to obtain a predetermined electrical resistance value at each position.

Next, as shown in FIG. 7, a second resistor section 28 is formed from above the first resistor section 23 by screen printing. As mentioned above, the first resistor part 23 uses a paste with a high resistance value, and each resistor part forming area 2
7A to 27G, the formation area of the first resistance section 23 per unit area, in other words, the density of the first resistance section 23 gradually changes, so that the first resistance section 2
3, almost the characteristics shown by curve B in FIG. 2 are obtained.

Therefore, the second resistance part 28 is filled between each of the first resistance parts 23 and has the role of smoothing the change characteristics of the resistance value, so the second resistance part 28 is made of a material having a smaller electrical resistance value than the first resistance part 23. It consists of In addition,
The gap between the first resistor parts 23 is very fine depending on the location, and if the viscosity of the resistance paste forming the second resistor part 28 is high, it will not fit into the fine gap between the first resistor parts 23. voids may be formed in the
When voids are formed in this way, the electrical resistance value changes, making it impossible to obtain desired resistance characteristics. Therefore, it is desirable that the resistance paste forming the second resistance part 28 has good permeability, such as by increasing the content of a solvent or by decreasing the content of a viscous agent.

The second resistance portion 28 also has the role of flattening the surface of the resistance layer and smoothing the sliding of the slider.

In the above embodiment, the planar shape of the first resistance section 23 was described as a square, but the present invention is not limited to this. do not have.

The present invention is applicable not only to so-called sliding type variable resistors but also to rotating type variable resistors.

The present invention has the above-described configuration, and has good resistance value change characteristics and smooth movement of the slider, and reduces motion errors when variable resistors having such resistance parts are used in multiple stages. It has advantages such as less

[Brief explanation of the drawing]

Figure 1 is a plan view of the resistance board of the variable resistor, Figure 2
The figure is a resistance value characteristic diagram, Figure 3 is a partial sectional view of a conventional resistance board, Figures 4 to 7 are for explaining embodiments of the present invention, and Figure 4 is a plan view of a screen. , FIG. 5 and FIG. 6 are a partial plan view and a partial cross-sectional view showing the process of manufacturing the resistor substrate of the present invention,
FIG. 7 is a cross-sectional view showing the state of the resistor board after it has been manufactured. 21... Insulating substrate, 23... First resistance section, 27
A to 27G...Resistance part formation region, 28...Second resistance part.

Claims (1)

[Scope of Claims] 1. Dot-shaped first resistance parts having different areas and intervals are formed on the substrate surface in a substantially band-like shape, and on the first resistance parts, a continuous layer having different electric resistance values from the first resistance parts is formed. A variable resistor characterized in that a second resistance section is formed. 2. The variable resistor according to claim 1, wherein the second resistance section has a smaller electrical resistance value than the first resistance section. 3. The variable resistor according to claim 1, wherein the resistance paste for forming the second resistance portion is a paste with good permeability.