JPS6320081Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a chip resistor used in an electronic circuit device.

In recent years, electronic circuit devices used in consumer and industrial equipment have become increasingly dense with wiring patterns due to the demand for higher integration, and electronic components have become increasingly finer, especially chip resistors. .

A conventionally used chip resistor will be explained using FIG. 2, which shows a plan view of FIG. 1 and a sectional view taken along the line ``--'' in FIG. In a conventional chip resistor, an electrode conductor 2 and a resistor 3 are formed on an insulating substrate 1 made of a material such as ceramic.

The electrode conductor 2 and the resistor 3 were formed using a conductive paste and a resistive paste, respectively, by a technique such as a thick film technique. The chip resistor 20 thus formed is mounted on a printed circuit board 10 made of glass, epoxy, phenol, etc., together with a chip capacitor 21, a semiconductor element 22, etc., as shown in FIG. After that, the chip resistor 2 is mounted by a method called functional trimming using a laser or the like so that the overall electrical characteristics of the electronic circuit formed on the printed circuit board 10 have the required values.
0 is cut off, and the resistance value of the chip resistor 20 is adjusted by the trimming portion 20a.

When functionally trimming the chip resistor 20 mounted on the printed circuit board 10, the conventional chip resistor has a resistor 3 formed on the entire surface of the insulating substrate 1 as shown in FIGS. 1 and 2. Therefore, if the laser beam is irradiated, the printed circuit board 10 near the chip resistor 20 and the conductor pattern (not shown) on the printed circuit board 10 may be cut and the circuit may no longer function as an electronic circuit. However, the drawback was that its reliability was significantly impaired.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional ones, and aims to provide a chip resistor whose resistor can be easily trimmed and which has good reliability.

The chip resistor according to this invention includes an electrode conductor on an insulating substrate and a resistor formed to be electrically connected to the electrode conductor. One orthogonal side is made to coincide with one side of the insulating substrate, and a blank space is provided between the other side of the resistor and the other side of the insulating substrate.

An embodiment of this invention will be described below with reference to FIGS. 4 and 5. FIG. 4 is a plan view of the chip resistor according to this invention, and FIG. 5 is a sectional view taken along the line ``--'' in FIG.

First, an electrode conductor 2 is formed on an insulating substrate 1 made of a material such as ceramic by a thick film technique using a conductive paste.

After that, the resistor 30 is connected to the electrode conductor 2 as shown in the figure.
A portion of the electrode conductor 2 is covered and brought close to the terminal of the insulating substrate 1, and is formed using a resistive paste in the same manner as the electrode conductor 2. By the way, one side of the resistor 30 coincides with one side of the insulating substrate 1, but a blank portion 40 is formed between the other side of the resistor 30 and the other end of the insulating substrate 1.

Generally, a YAG laser is used for trimming film resistors.The beam diameter of this YAG laser is 50 to 60 μm, and the beam energy of the first to third pulses immediately after the start of trimming is extremely large. Irradiating a film resistor with a laser beam causes large thermal distortion in the film resistor, leading to an increase in the temperature coefficient of resistance and an increase in the change in resistance value over time, which significantly deteriorates the performance and reliability of the film resistor. become.

However, in the present invention, one side of the film resistor is aligned with one side of the end surface of the substrate, a large distance is created between the other side of the film resistor and the other side of the end surface of the substrate, and the laser beam is directed into this blank space. The chip resistor 20 configured in this way
, the chip capacitor 21 as shown in FIG.
and the printed circuit board 1 together with the semiconductor element 22, etc.
When the chip resistor 20 is functionally trimmed using a laser so that the overall electrical characteristics of the electronic circuit have the required value after being mounted on the chip resistor 20, the chip resistor 20 is
Since there is a blank space 40 of 0, the printed circuit board 1
Also, high reliability can be obtained without damaging the conductor pattern (not shown). That is, since the resistor 30 can be cut in the direction of the arrow from point A of the blank space 40 in FIG. 4, the above effect can be obtained.

According to the inventors' experiments and studies, the above blank area 4
It has been found that the above-mentioned functional trimming can be carried out sufficiently if the width of 0, that is, the distance between the resistor 30 and the end of the insulating substrate 1 is about 0.2 mm to 0.3 mm.

In addition, the chip resistor 20 has a variation in resistance value of 20
Since the resistance value is approximately 30%, it is easy to trim the chip resistor 20 alone using a laser or the like, in addition to the above-mentioned functional trimming, for example, in order to make the resistance value accuracy within ±5%.

In the above embodiment, the electrode conductor 2 is placed on the insulating substrate 1.
Although the resistor 30 is formed after forming the resistor 30, the order of the steps may be reversed, and the resistor 30 may be formed by covering part of the electrode conductor 2 and the resistor 30.
Of course, an insulating layer made of glass or the like may be formed for the purpose of improving the electrical characteristics of the 0. Furthermore, in the above embodiment, the width of the electrode conductor 2 is set to the width of the resistor 30.
Although the width is made larger than that of , it may be the same size.

As described above, according to this invention, in a chip resistor including an electrode conductor 2 formed on an insulating substrate 1 and a resistor 3 connected to the electrode conductor 2, the resistor 3 and the insulating Since a blank space is provided between the circuit board 1 and the circuit board 1, trimming is easy, and functional trimming after mounting on the printed circuit board is also easy, resulting in a highly reliable chip resistor. .

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a conventional chip resistor, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a plan view showing a conventional chip resistor mounted on a printed circuit board. FIG. 4 is a plan view showing a chip resistor according to an embodiment of the invention, and FIG. 5 is a sectional view taken along the line -- in FIG. In the figure, 1 is an insulating substrate, 2 is an electrode conductor,
3 and 30 are resistors, 10 is a printed circuit board, 20 is a chip resistor, 21 is a chip capacitor, 22
20 is a semiconductor element, 20a is a trimming portion, and 40 is a blank portion. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] A chip resistor including an insulating substrate, an electrode conductor formed on the insulating substrate, and a resistor formed on the electrode conductor, A chip resistor characterized in that one side perpendicular to the electrode conductor coincides with one side of the insulating substrate, and a blank space is provided between the other side of the resistor and the other side of the insulating substrate.