JPS5999704A - Method of producing resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing a resistor, which accurately sets the resistance value of a resistor formed on a substrate by a printing method or a photographic method.' □ Conventional configurations and their problems In recent years, with the spread of electronic devices and the miniaturization and multi-products of devices, there has been a growing demand for high-density mounting of electronic components on printed circuit boards. In order to meet the requirements, ready-printed solder resistors are used for resistors; however, this printed resistor cannot be formed with a large current capacity due to the poor heat conduction of the printed circuit board. However, since the range in which the resistance value can be obtained by trimming is still narrow, it is necessary to print the resistance value several times to obtain the desired resistance value. This was due to the fact that the back gate of the resistor was extremely expensive. □ First, 1. De-crystallization was carried out using the conventional manufacturing method of the resistor using the method shown in FIGS. 1 and 2.

First of all, 1'ig<Oi □, 1 is a substrate such as a printed circuit board, J day is a fixed body □ layer such as carbon baylet formed on one stroke of the board, □' is the above-mentioned resistor. The electrodes 5 formed on both ends of the body layer 20 and made of silver or the like are made of epoxy resin or the like that protect the resistor layer 2 and the electrodes 3' and 4. The electrodes 5 are neo-barcodes made of □ to '-1''.

The resistance value of the resistor layer 2 is normally adjusted as shown in FIG.
G) Norming lines 6a, 6b, etc. by sandblasting method etc.
6c is formed. However, if the length of this trimming line becomes longer, the remaining portion of the resistor layer 2 will decrease, and the allowable current value will become smaller. Unless the trimming lines 6a to 6C are formed, the required resistance value cannot be obtained, and this requires trimming work at a later stage, resulting in poor workability.

Purpose of the Invention In view of the above-mentioned conventional problems, the present invention is capable of adjusting the resistance value over a wide range and with high precision in one trimming operation.
Furthermore, the present invention provides a method for manufacturing a resistor that can reduce the allowable power.

Structure of the Invention The present invention provides a comb-shaped structure in which a resistor layer is formed on a substrate by a printing method or a photographic method, and is made of a material that reflects laser light onto the resistor layer from opposite end sides of the resistor layer. This is a method of manufacturing a resistor in which electrodes are provided in a facing state and the resistor layer is trimmed with a laser beam.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

7 is a board such as a printed circuit board, and 8 and 9 are the board 7.
A copper foil is formed on top. 10 is a resistor layer formed by a printing method or a photographic method on the substrate T between the copper foils 8 and 9, and 11.12 is a resistor layer whose base end portions are the copper foils 8 and 9, respectively.
a material that reflects laser light and is connected to the resistor layer 10 and is formed on the resistor layer 10 so that the protrusions are located within the recesses;
For example, it is a phase ij type electrode made of silver or the like. Reference numeral 13 denotes an overcoat made of epoxy resin or the like that covers i% of the resistor layer 10 and the comb-shaped electrodes 11 and 12. 14 is the electric current from above the comb-shaped electrodes 11 and 12! 1 return 11.12
This is a trimming line formed by a laser beam so as to cross the protrusions and recesses.

In this way, the comb-shaped electrodes 11.12 are provided on the resistor layer 10 in a facing state, and the resistor is trimmed by a laser beam across the opposing portions of the comb-shaped electrodes 11. The connection area between the layer 10 and the comb-shaped electrode 11.12 is large, and as described above, the comb-shaped electrode 11.1
Even if trimmed across the opposing portions of the resistors 2 and 2, the permissible current will not decrease much, and therefore a resistor for large currents can be obtained with a small area.

In this case, by using carbon resistance paint mixed with graphite as the resistor layer 10, the change in resistance value due to trimming is more continuous than when using only carbon resistance paint mixed with graphite, and therefore the resistance value is minute. Adjustments can be made.

FIG. 6 shows another example of trimming, in which the trimming line 14 is arranged in an S-shape between the opposing parts of the comb-shaped +fi11°12 except for the beginning. In this case, the resistance value changes continuously, and minute resistance value adjustments can be made.

In addition, FIGS. 7(a) and 7(b) show the comb-shaped electrodes 11 and 12.
This shows other examples, and the same applies to those having the shapes shown in the figures.

Effects of the Invention As described above, in the present invention, the electrode is a comb-shaped electrode that reflects the laser beam, and the resistor layer is trimmed from above the comb-shaped electrode with a laser beam, thereby reducing the remaining resistance after trimming. Since the distance between the two electrodes is short in the body layer part, the allowable power can be increased, and the trimming distance can still be long, so a single trimming can provide a wide resistance value adjustment range, and the working part This makes it possible to reduce the number of printings of resistive paints having different resistance values and to reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a pi side view showing a conventional resistor, FIG. 2 is a top view showing the same trimming state, and FIG. 3 is a two side view showing an l-IJ trimming state of a resistor according to an embodiment of the present invention. Figure 4 is a sectional view taken along line A-A/ in Figure 3, Figure 5 is a sectional view taken along line BB' in Figure 3, Figure 6 is a top view showing an example of 1m trimming, and Figure 7 is a sectional view taken along line BB' in Figure 3. Figures (a) and (b) are diagrams showing examples of electrode shapes, respectively. 7...Substrate, 10...--Resistor layer, 11
．． 12...°・Comb-shaped electrode, 14...Trimming line. Name of agent: Patent attorney Toshio Nakao and 1 other person
Ward c3 L < D Sa. . law taste

Claims (1)

[Claims] (1) The substrate is made of a material on which a resistor layer is formed by printing or photography, and laser light is reflected onto the resistor layer from both opposing end sides of the resistor layer. Set the comb-shaped electrodes facing each other; the resistor layer is irradiated with a laser beam)! j. A method for manufacturing a resistor, which is characterized in that the resistor is subjected to microscopy. □(2) The method of manufacturing a resistor according to claim 1, wherein the resistor layer is trimmed between the comb shape and the front side of the pole.