JPH0372601A - Film resistor - Google Patents

Abstract

PURPOSE:To lessen the change in the resistance values proportional to the increase in trimming length thereby enabling the resistance values to be minutely adjusted by a method wherein, for film resistor adjusting by cutting a trimming groove in film resistor between a pair of electrodes, the distance between the electrodes is made smaller as it goes in the width direction of an insulating substrate. CONSTITUTION:Film electrodes 2 provided on an insulating substrate 1 are separated from each other in the Y direction while the length l thereof is made smaller as it goes in the X direction. A trimming groove 4 is cut by laser irradiation in a film resistor 3 provided between the film electrodes 2 to adjust the resistance value. Through these procedures, the length l between the film electrodes 2 can be made as it goes in the width direction, thereby enabling the change smaller in the resistance values proportional to the increase of the trimming length to be smaller than that of any conventional film resistors.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to improvements in membrane resistors.

<Prior art> For resistors such as film resistors and film resistance elements in printed circuits, a resistor is used in which a pair of electrodes are arranged on the film resistor and the resistance value between the electrodes is adjusted to a predetermined value. .

As shown in FIG. 2, a method is applied to the lx1 node of this resistance value, in which a trigonal groove 4' is inserted in the l+ direction. In other words, the initial resistance value of the film LL resistance 3° is set lower than a predetermined value, and trimming and resistance value measurement are performed alternately.If the predetermined resistance value has not been reached, trimming is continued and the predetermined resistance is If the value is within the range, trig- ging is stopped and the resistance is set to a predetermined resistance value within a predetermined tolerance range.

<Problem to be solved> However, in conventional film resistors, the distance between the electrodes 2° and 2° is constant regardless of the position in which the trimming progresses, and the distance between the electrodes 2° and 2° is constant, and the distance between the electrodes 2° and 2° is constant regardless of the position in which the trimming progresses. The change in resistance value as the length increases is large.

That is, in Fig. 2, the original resistance value R(x) of the trimming length Then, the original resistance value change ΔR(x) of the trimming length increase ΔX is as follows, and as the trimming length X increases, the resistance value change with respect to ΔX, that is, ΔR(X)/ΔX becomes quite large. Therefore, it is difficult to set the resistance value in a fine section 81s1, and the adjustment becomes rough, and the allowable range of the set resistance value must be widened. Therefore, this is disadvantageous in reducing the size of the membrane resistor.

An object of the present invention is to provide a film resistor that makes it possible to finely adjust the resistance value by reducing the change in resistance value as the length of trimming increases.

<Means for Solving the Problems> The membrane 11 (antibody) according to the present invention comprises a pair of membrane electrodes spaced apart in the longitudinal direction on an insulating substrate and an inter-electrode membrane resistor, and the membrane resistor has a resistance value #A. This resistor is provided with trimming grooves in the width direction for knots, and is characterized in that the distance between the electrodes becomes narrower in the width direction.

<Explanation of Examples> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory plan view showing one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an insulating substrate, such as a ceramic board. 2.2 is a membrane electrode provided on an insulating substrate, and is directed in the Y direction (
(longitudinal direction), and the distance 1 becomes narrower toward the X direction.

3 is a membrane resistor provided between the electrodes. Reference numeral 4 denotes a trimming groove for adjusting the resistance value, which is formed by laser irradiation and reaches a medium to small amount of film resistance from the insulating substrate.

The above membrane electrode can be formed by printing and baking a conductive paint mixed with conductive metal powder. The film resistor can be formed by printing and baking a resistive paint mixed with a resistive powder such as metal oxide carbon.

It is also possible to form a film resistor by etching the resistive film of a substrate in which a resistive film is laminated on an insulating base material, then vapor depositing electrode aluminum, and printing/baking a conductive paint.

In the above, if the specific heat between the electrodes at a certain point in the The resistance value r (x) is approximately expressed by the following equation.

Further, the resistance value change Δr (x) when the trimming length increase is ΔX is as follows.

In Fig. 1, the distance between the electrodes is still 41!
If (X) is set as 1(x)=L−kx, then k can be selected so as to satisfy Δr (x) <ΔR(x) −■.

Therefore, in the film resistor according to the present invention 1!11, it is possible to make the change in resistance value with respect to an increase in the trimming length smaller than that of the conventional film resistor, and it is possible to finely adjust the resistance value by trimming. Become.

In the above, regarding the method of decreasing the inter-electrode spacing with respect to the increase in X, it is more advantageous to decrease it hyperbolically rather than linearly.

The present invention can also perform trimming from both sides, in which case it is necessary to narrow the inter-electrode spacing with respect to the progress of each trimming. Furthermore, L-cut, J-cut, etc. can be used for trimming. <Effects of the Invention> As described above, in the film resistor according to the present invention, the amount of change in resistance value with respect to increase in trimming length can be reduced. Therefore, it is possible to finely adjust the resistance value, and it is useful as an ultra-small film resistor or a film resistor for a circuit.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a conventional example. 1...Insulating substrate 2...Membrane electrode 3.
...Membrane resistor 4...Trimming groove

Claims (1)

[Claims] In a resistor comprising a pair of membrane electrodes spaced apart in the longitudinal direction on an insulating substrate and an inter-electrode membrane resistor, the membrane resistor is provided with a trimming groove in the width direction for adjusting the resistance value. A membrane resistor characterized by narrower spacing between electrodes.