JPH0574615A - Adjusting method for resistance value and laser trimming equipment - Google Patents

Abstract

PURPOSE:To obtain a resistor of high reliability through which a large current can be made to flow when a printed resistor on a printed wiring board is subjected to laser light trimming. CONSTITUTION:Trimming is performed at an arbitrary angle to the current direction of a printed resistor 2 on the printed wiring board 3. Hence intervals between the end points of a plurality of trimming lines 4a, 4b are increased, and the absolute area where a current flows is kept large. Thereby the printed resistor 2 of high reliability can be obtained. In this case, trimming is enabled at an arbitrary angle to the current direction, by making the printed board fixing part of a laser trimming equipment to be used rotatably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the resistance value of a resistor on a printed wiring board and a laser trimming device when it is necessary to perform function trimming by laser light in a consumer electronic device. is there.

[0002]

2. Description of the Related Art In recent years, the functionality of printed wiring boards has been improved, and resistors, capacitors, etc. are built in the surface of the printed wiring boards. When performing functional trimming by laser light, as shown in FIG. 3, the printed resistor 2 is formed vertically between the electrode terminals 1 on the surface of the printed wiring board 3 so as to be perpendicular to the current flow direction. Trimming was performed by laser light so that

The laser trimming line 4a is a straight line perpendicular or parallel to the printed resistor 2, and a target resistance value is obtained by this combination.

That is, a method of cutting a few in the direction perpendicular to the current direction of the printed resistor 2 or a method of starting the cutting in the vertical direction and cutting in the parallel direction at a certain portion has been used.

Further, since the printed wiring board mounting portion of the laser trimming device operates only in the X-axis direction or the Y-axis direction during trimming, linear trimming is performed in the X-axis direction and the Y-axis direction.

[0006]

However, in the above-described method of adjusting the resistance value by the trimming shape, in order to obtain the target resistance value, when several laser trimming lines are put in the printed resistor 2, the line spacing is set. Is too close, the end of the line is too close, or the line is printed resistor 2
If it is too deep with respect to the width of, the resistance value changes even after the trimming is completed, and the resistor becomes unreliable.

Further, there is a problem that the absolute portion through which the current of the resistor flows is reduced by the trimming, the heat generation becomes remarkable, and the large capacity cannot be endured.

In view of the above-mentioned problems of the conventional trimming method, the present invention provides a highly reliable method for adjusting the resistance value of a large-capacity printed resistor by laser trimming, and an apparatus therefor.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method of trimming a printed resistor formed on a printed wiring board by laser light in a direction perpendicular to a current flow. On the other hand, this is a method of adjusting the resistance value by trimming at an arbitrary angle.

Further, there is provided a method of adjusting the resistance value in which the printed resistor is a chip type fixed resistor.

A laser trimming device is provided with a rotatable printed wiring board mounting portion.

[0012]

According to the method of adjusting the resistance value in laser trimming of the present invention, trimming is performed at an angle to the direction perpendicular to the current flow of the resistor, that is, the end point of the first trimming line. Since the distance between the diagonally trimmed second end point becomes longer, a cutting shape having a larger absolute area of the resistor can be realized, and the rate of change after trimming is small, and a resistor capable of withstanding a large capacity is obtained. be able to.

Further, according to the laser trimming device, the printed wiring board mounting portion can be rotated so that the trimming line of the resistor can be moved in the current direction without moving simultaneously in the X axis direction and the Y axis direction. Can be cut diagonally. Then, it is possible to cut by changing the angles of the first trimming line and the second trimming line.

[0014]

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

FIG. 1 is a diagram showing an example of a resistance value adjusting method of the present invention. The printed resistor 2 formed between the electrode terminals 1 on the printed wiring board 3 is laser trimmed by a laser trimming device.

In the method of adjusting the resistance value, a trimming line 4a perpendicular to the current direction and an oblique trimming line 4b having an angle are cut from the printed resistor 2 by a laser trimming device.

In the conventional method of adjusting the resistance value of the printed resistor, the printed resistor 2 is cut with several laser trimming lines 4a perpendicular to the current direction. Therefore, when several trimming lines 4a are inserted, the end points of the trimming lines are close to each other, the resistance value changes even after the trimming is completed, and the resistor becomes reliable.

However, according to this resistance value adjusting method, the trimming line 4a perpendicular to the current direction is inserted into the printed resistor 2 as a first cut, and the second and subsequent lines have an angle with the current direction. Diagonal trimming line 4b like
By inserting, the distance of the end point can be lengthened and the line interval can be widened. Therefore, the printed resistor 2
It is possible to adjust the resistance value while maintaining a large absolute area where the current flows, and a large capacity current can flow.

As described above, according to the present embodiment, by inserting the trimming line 4a and the diagonal trimming line 4b into the printed resistor 2, the line spacing can be widened.
The end points of the lines can be separated, and the printed resistor 2 having a large current capacity can be obtained.

Next, FIG. 2 shows a diagram for explaining a printed wiring board mounting portion of the laser trimming device.

In this printed wiring board mounting portion, a bearing 7 is formed on the conventional mounting portion 8, a mounting plate 5 having a rotating shaft 6 for the bearing 7 is mounted thereon, and a printed wiring board having a resistor to be trimmed is mounted thereon. 3 is fixed.

Since the conventional mounting portion operates only in the X-axis direction or the Y-axis direction, it is impossible to obtain an oblique trimming line.

However, in this printed wiring board mounting portion, by rotating the mounting plate 5, it is possible to obtain an oblique trimming line with respect to the printed resistor 2 on the printed wiring board 3.

That is, in order to obtain the cutting shape as shown in FIG. 1, the first trimming is performed without rotating the mounting plate 5, and the + θ ° mounting plate 5 is rotated when the second trimming is performed. .. Furthermore, from that place, -2θ ° mounting plate 5
Trim after rotating.

With the above structure, a trimming line having an arbitrary angle with respect to the current direction of the printed resistor can be formed.

The present invention is also applicable when the printed resistor is a chip type fixed resistor.

[0027]

As described above, according to the method of adjusting the resistance value of the present invention, when the resistor formed on the printed wiring board is functionally trimmed by the laser beam, it can be arbitrarily set in the direction perpendicular to the current flow. By trimming with the angle of, the trimming line interval can be kept wide, the end point distance can be kept long, the absolute area through which the current flows can be increased, and a large-capacity resistor with little change after trimming. Can be made.

Further, by making the mounting portion of the laser trimming device according to the present invention rotatable, diagonal trimming can be performed by the conventional trimming device.
It is possible to cut by changing the angles of the first and second trimming lines.

[Brief description of drawings]

FIG. 1 is a plan view of a trimming shape of a printed resistor according to an exemplary embodiment of the present invention.

FIG. 2 is a side view of a mounting portion of a laser trimming device according to an embodiment of the present invention.

FIG. 3 is a plan view of a trimming shape of a conventional printed resistor.

[Explanation of symbols]

 1 Electrode Terminal 2 Printed Resistor 3 Printed Wiring Board 4a Trimming Line 4b Diagonal Trimming Line 5 Mounting Plate 6 Rotating Shaft 7 Bearing 8 Conventional Mounting Area

Claims (3)

[Claims] 1. When a resistor formed on a printed wiring board is functionally trimmed by laser light, the resistor is trimmed at an arbitrary angle with respect to a direction perpendicular to a current flow. Adjustment method. 2. The resistance value adjusting method according to claim 1, wherein the resistor is a chip-type fixed resistor. 3. A laser trimming device, wherein a printed wiring board mounting portion holding a printed wiring board having a resistor to be laser trimmed is rotatable.