JPH04196502A - Resistor trimming equipment - Google Patents

Abstract

PURPOSE:To realize stable resistor trimming with high precision, independently of the irregularity of initial resistance value of a resistor element, by installing a first target resistance value setting means which changes and sets a first target resistance value in response to the initial resistance value of a resistance element before an L-shaped cut part is formed, and commands a laser cut controlling means to get the first target resistance value which has been changed and set. CONSTITUTION:A laser cut controlling means 4 compares a first target resistance value set by a first target resistance value setting means 2 so as to correspond with the initial resistance value of a resistance element 6, with resistance value measured by a resistance value measuring means 1, and controls a laser cut means 5 so as to make the resistance value of the resistance element coincide with the first target resistance value, thereby forming an L-shaped cut part 8. The laser cut controlling means compares a second target resistance value being the final target resistance value, with a resistance value measured by the resistance value measuring means, and controls the laser cut means so as to make the resistance value of the resistance element equal to the second target resistance value, thereby forming a rectilinear cut part 9. As a result, stable trimming with high precision can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resistance trimming device for trimming the resistance value of a resistance element using a laser.

2. Description of the Related Art For example, laser trimming is known in which the resistance value of a resistance element printed on an alumina plate is trimmed with high precision.

FIG. 3 is an explanatory diagram of the above-mentioned laser trimming. First, an L-shaped cut portion 8 is formed on the surface of the resistive element 6 by a laser, a first fine adjustment is performed, and then a straight cut portion 8 is formed on the surface of the resistive element 6. A second fine adjustment is performed by forming the cut portion 9 with a laser, and the resistance value between the conductors 7a and 7b is
In other words, the resistance value of the resistance element 6 is trimmed. The reason why the cut part 8 is L-shaped is that if the cut part 8 is made into a straight line extending in the vertical direction in FIG. This is because microcracks occur in the direction of extension, causing a large change in resistance value.

If the cut portion 8 is formed into an L-shape, microcracks extending in the lateral direction in FIG. 3 will occur at the laser stop point, but this will have little effect on the resistance value. In other words, as shown in Fig. 6, the change in resistance value due to L-cuts is as follows: when the length of the straight cut part is 14, the change is shown by the solid line RL, and when the length of the straight cut part is 13, the change in resistance value is shown by the broken line RL2. It becomes like this.

Further, the reason why the straight cut part 9 is formed after the L cut part 8 is formed is the resistance value (broken line R in FIG. 5) with respect to the length of the straight cut part 9 after the L cut part 8 is formed.
t) is the resistance value when forming the straight cut part 9 before forming the L cut part 8 (solid line Rs in FIG. 5).
This is because the amount of change is smaller than the amount of change in , and the resistance can be finely adjusted with higher precision.

FIG. 4 is an operation flowchart of the laser trimming described above.

In step 20 of FIG.
The cut portion 8 is cut in the vertical direction (in the upward direction in the drawing), and in step 21, the resistance value of the resistance element 6 is measured by a resistance measuring means (not shown). Then, in step 22, it is determined whether the measured resistance value is a percentage (for example, 85%) of the final target value, and if it is less than K%, the process returns to step 20. If K% has been reached,
The process proceeds to step 23, where an L-turn is made at the location where the vertical dimension ja of the L-cut portion 8 is reached, and a horizontal cut is executed, and the process proceeds to step 24. In this step 24, the execution of the straight cut, that is, the formation of the straight cut portion 9 is started. Next, in step 25, the resistance element 6
The resistance value is measured, and in step 26 it is determined whether the measured resistance value has reached the final target value. Then, if the resistance value has not reached the final target value, step 2
Returning to step 4, if the length has been reached, the length of the straight cut portion 9 is set to lb in step 27, and the straight cut is completed.

As described above, the resistance value of the resistance element 6 is adjusted to the L cut portion 8.
Fine adjustment is made by adjusting the length of and the length of the straight cut part 9.

Problems to be Solved by the Invention In the above-mentioned conventional resistance trimming, the length in the vertical direction of the L-cut portion 8 is set so that the resistance value reaches % of the final target value, and the value of % is determined by the predetermined value. The initial resistance value of resistor element 6 (resistance value before trimming)
It is a constant value, for example, 85%, regardless of the size of .

Therefore, when the initial resistance value of the resistance element 6 is near the lower limit value within the allowable range, the length of the L cut portion 8 in the vertical direction becomes long as shown in FIG. The amount of change in the resistance value with respect to the length of the straight cut portion 9 changes depending on the length in the longitudinal direction of the L cut portion 8, and the longer the length in the longitudinal direction, the smaller the amount of change in the resistance value. therefore,
To obtain the final resistance value, straight cut section 9
The length is longer than the longitudinal length lc of the L-cut portion 8.
Only d is required.

However, if the length of the straight cut section 9 exceeds the longitudinal length Inc of the L cut section 8, the amount of change in resistance value increases rapidly, making it difficult to accurately adjust the resistance value to the final value. there were.

Further, when the initial resistance value of the resistance element 6 is around the upper limit value within the allowable range, the length in the vertical direction of the L-cut portion 8 becomes a short dimension lf as shown in FIG. In this case, in order to obtain the final resistance value, the length of the straight cut portion 9 becomes the short dimension Ale.

However, since the amount of change in the resistance value with respect to the length of the straight cut portion 9 is large, it is difficult to accurately adjust the final resistance value as in the case where the initial resistance value is near the lower limit value described above. It was difficult.

Means for Solving the Problems Therefore, in order to solve the above-mentioned problems, the present invention provides a resistance value measuring means for measuring the resistance value of a resistance element, and a cut portion in the shape of an abbreviation formed by a laser on the surface of the resistance element. After that, laser cutting means forms a straight cut part near this L-shaped cut part, and the resistance value of the resistance element becomes the first target resistance value by the L-shaped cut part, and the linear force laser cutter control means for adjusting the dimensions of the L-shaped cut part and the linear cut part by controlling the laser cutting means so that the second target resistance value is achieved by the point part;
(In step 1, according to the initial resistance value of the resistance element before the L-shaped cut part is formed,
The present invention is characterized in that it includes first target resistance value setting means for changing and setting the first target resistance value and instructing the laser cutting control means to change and set the first target resistance value.

The operation laser cutting control means compares the first target resistance value set by the first target resistance value setting means according to the initial resistance value of the resistance element with the resistance value measured by the resistance value measuring means (the resistance value measuring means). The laser cartridge is controlled so that the resistance value of the element becomes the first target resistance value, and an L-shaped force is applied.
Form a soto part.

Then, the laser cartridge control means compares the second target resistance value, which is the final target resistance value, with the resistance value measured by the resistance value measuring means, and the resistance value of the resistance element is determined to be the second target resistance value. A straight cut portion is formed by controlling the laser cutting means so as to obtain the desired value.

Example FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, 1 is a resistance value measuring means for measuring the resistance value of a resistance element, 2 is an L-turn trimming target value setting means (first target resistance value setting means), and 3 is a storage means. stores various turn trimming target values (%) corresponding to the initial resistance value. Further, 4 is a laser cut control means, 5 is a laser cut means,
This laser cut means 5 is a laser cut control means 4.
An L-cut portion 8 and a linear straight-cut portion 9 are formed in the resistance element 6 under the control of the following.

Next, the operation of the example shown in FIG. 1 will be explained with reference to the operation flowchart shown in FIG.

In step 10 of FIG. 2, the initial resistance value of the resistance element 6 is measured by the resistance value measuring means 1, and the measured initial resistance value is supplied to the L-turn trimming target value setting means 2. Next, in step 11, the L-turn trimming target value setting means 2 retrieves the L-turn trimming target value (%) (first target resistance value) corresponding to the initial resistance value from the storage means 3 and sends it to the laser cut control means 4. supply This L-turn trimming target value is set small if the initial resistance value is small, and large if the initial resistance value is large.

For example, if the final resistance value is 100Ω and the initial resistance value is 5OKΩ to 55Ω, the L turn trimming target value is 85.5%, or 85.5Ω, and the initial resistance value is 65Ω to If Ω is 70, the L turn trimming target value is 87.
, 0%, that is, 87Ω. Subsequently, in step 12, the laser cut control means 4 controls the laser cut means 5 to start cutting the L cut portion 8 in the longitudinal direction. Then, in step 13,
The resistance value of the resistance element 6 is measured by the measuring means 1, and the measured resistance value is supplied to the laser cutting control means 4. Then, in step 14, the control means 4 determines whether the measured resistance value has reached the L-turn trimming target value, and if it has not reached it, the process returns to step 12. If the resistance value has reached the L-turn trimming target value, the process proceeds to step 15, where the control means 4 controls the laser cutting means 5 to perform an L-turn and perform a lateral cut.

Next, in step 16, the laser cutting means 5 is controlled by the laser cutting control means 4, and the execution of straight cutting, that is, the formation of the straight cut portion 9 is started. Then, in step 17, the resistance value of the resistance element 6 is measured by the measuring means 1, and the measured resistance value is supplied to the control means 4. Then step 1
At step 8, the control means 4 determines whether the resistance value of the resistance element 6 has reached the final target value (second target resistance value), and if it has not reached the final target value, the process returns to step 16. If the resistance value of the resistor element 6 has reached the final target value, the process proceeds to step 19, where the straight cut is completed.
Trimming of the resistance value of the resistance element 6 is completed.

As described above, according to one embodiment of the present invention, when the initial resistance value of the resistance element 6 is small, the L-turn trimming target value is set small, and when the initial resistance value is large, the L-turn trimming target value is set small. The trimming target value is set to a large value. Therefore, when the initial resistance value is small, the vertical dimension of the L-turn cut part is set to an appropriate dimension shorter than the dimension 1c shown in FIG. 7, for example, and when the initial resistance is large, the vertical dimension of the L-turn cut part The directional dimension is, for example, the 8th
The length of the straight cut portion 9 will not become extremely long or short, and stable and highly accurate trimming will be possible regardless of variations in initial resistance value. It becomes possible.

Effects of the Invention As described above, according to the present invention, there is provided a resistance value measuring means for measuring the resistance value of a resistance element, and a resistance value measuring means for measuring the resistance value of a resistance element. Laser cutting means forms a straight cut part near the cut part, and the resistance value of the resistance element becomes a first target resistance value by the L-shaped cut part, and a second target resistance by the straight cut part. In the resistance trimming device, the L-shaped cut portion is formed, the resistance trimming device having a laser cut control device controlling the laser cutting device to adjust the dimensions of the L-shaped cut portion and the linear cut portion so as to obtain the desired value. A first target resistance value setting means is provided for changing and setting the first target resistance value according to the previous initial resistance value of the resistance element and instructing the laser cutting control means to use the changed first target resistance value. As a result, stable and highly accurate resistance trimming can be performed regardless of variations in the initial resistance values of the resistance elements.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an operation flowchart of the example shown in FIG. 1, FIG. 3 is an explanatory diagram of laser trimming, and FIG. 4 is an operation flowchart of the conventional example.
Figure 5 is a graph showing the relationship between straight cut length and resistance value, Figure 6 is a graph showing the relationship between L cut length and resistance value, and Figures 7 and 8 are graphs showing the relationship between straight cut length and resistance value. FIG. 3 is a diagram for explaining that . DESCRIPTION OF SYMBOLS 1... Resistance value measuring means, 2... L-turn trimming target value setting means, 3... Memory means, 4... Laser cutting control means, 5 - Laser cutting means, 6...
- Resistance element, 8... L cut part, 9... Straight cut part. Fig. 2 Fig. 3 Fig. 9 Straight cut section Fig. 4 Fig. 5 Room 11 12 Straight cut length Fig. 6

Claims (1)

[Claims] (1) a resistance value measuring means for measuring the resistance value of a resistance element;
A laser cutting means for forming a substantially L-shaped cut part on the surface of a resistor element using a laser and then forming a linear cut part in the vicinity of the L-shaped cut part; The cut part provides the first target resistance value,
A resistance trimming device comprising: laser cut control means for adjusting the dimensions of the L-shaped cut portion and the linear cut portion by controlling the laser cut means so that the linear cut portion reaches a second target resistance value. In this step, the first target resistance value is changed and set according to the initial resistance value of the resistance element before the L-shaped cut portion is formed, and the changed first target resistance value is sent to the laser cutting control means. 1. A resistance trimming device comprising first target resistance value setting means for issuing a command.