JPH0428202A - Square-shaped chip resistor used for regulation - Google Patents

Abstract

PURPOSE:To unnecessitate the checkup of a resistance value before mounting, to easily conduct a visual observation on an indicating part using a magnifying glass and the like, and to confirm the range of resistance value which can be adjusted by a method wherein an indicating part, on which adjustable range of resistance value is clearly mentioned, is provided on the surface of a housing. CONSTITUTION:The title square-shaped chip resistor is composed of a 96-alumina substrate 1, a top electrode layer 2, consisting of a silver thick film electrode, an edge electrode layer 3, a resistance layer 4 consisting of a ruthenium thick film resistor, a glass layer (green color) 5 on the resistance layer 4, and an indicating part 6 (initial resistance value is indicated by white color, and the maximum correctable value is indicated by yellow color) consisting of marked glass. Besides, an Ni plated layer 7 and an Sn-Pb plated layer 8 are provided on the surface of an exposed electrode by conducting electrolytic plating in order to improve solderability. By having the above-mentioned constitution, the range of adjustable resistance value can be confirmed by visually observing the indicating part 6 instead of checking the resistance value before mounting. Also, the time required for confirmation can be reduced to about 1/100 from that required before by conducting a mechanical inspection using pattern recognition and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an adjustable rectangular chip resistor that is mainly mounted on a high-density wiring circuit by an automatic mounting machine and used for modifying the function of the circuit.

Conventional technology In recent years, with the increasing demand for electronic devices to be lighter, thinner, and smaller, very small square chip resistors are increasingly being used as resistance elements in order to increase the wiring density of circuit boards. It's here.

Furthermore, since the resistance value of this square chip resistor can be adjusted by laser trimming or the like after being mounted on a circuit board, it is being used for adjustment purposes and is being replaced by surface-mounted semi-fixed resistors.

The cross-sectional structure of a conventional rectangular chip resistor for adjustment is shown in FIG. A conventional square chip resistor for adjustment includes a 96 alumina substrate 11, a top electrode layer 12 and an end electrode layer 13 made of a silver-based thick film electrode, and a resistance layer 14 made of a ruthenium-based thick film resistor.
It consists of a glass layer 15 on a resistive layer 14. Note that Ni is applied to the exposed electrode surface to improve soldering properties.
The plating layer 1-6 and the 5n-Pb plating layer 17 are applied by electrolytic plating.

Problems to be Solved by the Invention However, in the conventional rectangular chip resistor for adjustment, the resistance value is not displayed, just as in the conventional rectangular chip resistor whose resistance value is not adjusted after mounting, the resistance value is not displayed. It wasn't. Furthermore, the adjustable range was not clearly specified. For this reason, the only way to determine whether a specified square chip resistor for adjustment is mounted on a circuit board is to measure its resistance immediately before mounting, which poses the problem of an extremely complicated inspection process when handling a large number of resistors. there were.

In order to solve the above problems, an object of the present invention is to mount an adjustable rectangular chip resistor having an appropriate resistance value range without a complicated testing process.

Means for Solving the Problems The rectangular chip resistor for adjustment of the present invention is configured to have a display section on the surface of the casing that specifies the range of adjustable resistance values.

Function: According to the rectangular chip resistor for adjustment of the present invention, there is no need to check the resistance value before mounting, which was complicated in conventional rectangular chip resistors for adjustment, and instead, the display part can be easily checked visually using a magnifying glass or the like. This allows you to check the adjustable resistance value range. Another advantage is that it can be mechanically inspected using pattern recognition or the like.

EXAMPLE Hereinafter, a rectangular chip resistor for adjustment according to an example of the present invention will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view.

First, in FIGS. 1 and 2, the rectangular chip resistor for adjustment of the present invention includes a 96 alumina substrate 1, a top electrode layer 2 and an end electrode layer 3 made of silver-based thick film electrodes, and a ruthenium-based thick film resistor. A glass layer (green) 5 on the resistance layer 4, and a display section 6 made of stamped glass (the initial resistance value is displayed in white and the maximum correctable resistance value is displayed in yellow). ing. In order to improve solderability, a Ni plating layer 7 and a Sn--Pb plating layer 8 are applied to the exposed electrode surface by electrolytic plating.

Next, the manufacturing method of this example will be explained.

First, a 96 alumina substrate 1 having excellent heat resistance and insulation properties is inserted. In order to divide the alumina substrate 1 into strips and individual pieces, grooves for dividing the alumina substrate 1 (molded with a mold when forming a green sheet) are formed. Next, the above 9
6 A thick film silver paste is screen printed on the alumina substrate 1 and fired in a belt type continuous firing furnace at a temperature of 850°C with a peak time of 6 minutes and a profile of 1N-0UT of 4.5 minutes to form the top electrode layer 2. .

Next, the RIJO 2
Screen print a thick film resistor paste whose main ingredient is
The resistive layer 4 is formed by firing in a belt-type continuous firing furnace at a temperature of 850° C. according to a profile of a peak time of 6 minutes and an IN-0UT time of 45 minutes. Next, a glass paste (green) is screen printed so as to completely cover the resistance layer 4, and is dried at 150° C. for 10 minutes in a near-infrared drying oven. Furthermore, a stamped glass paste (white) is screen printed on the dried glass paste and dried for 180 minutes at 110° C. in a near-infrared drying oven. moreover,
A stamped glass paste (yellow) was screen printed on the dried glass paste and dried at 110° C. for 10 minutes in a near-infrared drying oven. After that, it was heated in a belt-type continuous firing furnace at a temperature of 590°C for a peak time of 6 minutes and lN.
The glass layer 5 and the display section 6 made of stamp glass are simultaneously formed by firing according to the firing profile of -0UT for 50 minutes.

Next, as a preparatory step for forming the end electrodes, the alumina substrate 1 is divided into strips to expose the end electrodes, and primary substrate division is performed to obtain strip-shaped alumina substrates. A thick film silver paste was applied by a roller to the side surface of the strip-shaped alumina substrate so as to overlap a part of the upper electrode layer 2, and heated in a belt-type continuous firing furnace at a temperature of 600° C. for a peak time of 6 minutes at 1N. The end face electrode layer 3 is formed by firing according to the firing profile of -0UT45 minutes. Next, as a preparation step for the electrode plating step, the end surface electrode layer 3
Secondary substrate division was carried out by dividing the rectangular alumina substrate, which had already been formed, into individual pieces to obtain individual piece-shaped alumina substrates. Finally, the exposed top electrode layer 2 and end electrode layer 3 are soldered using electrolytic plating to prevent the electrodes from being eaten away and to ensure soldering reliability.
Electrolytic plating is performed to form a Sn--Pb plating layer 8.

Through the following two steps, the rectangular chip resistor for adjustment of this example was manufactured as a prototype.

According to this embodiment, the adjustable resistance value range can be confirmed by visually observing the display section 6 instead of checking the resistance value before mounting. Furthermore, if the inspection is performed mechanically using pattern recognition or the like, the time required for confirmation is short, and the inspection time is reduced to about 1/100 compared to the conventional method.

This rectangular chip resistor for adjustment was mounted on a circuit board and laser trimmed (Z cut).

An explanatory view of the main parts at this time is shown in FIG. Since the central portions of the two display sections 6 are laser trimmed, the display does not become an obstacle to laser trimming.

In addition, in the example, white glass was used to display the initial resistance value, and yellow glass was used to display the maximum correctable resistance value range, but this does not limit the display color, and the same color may be used (however, The color combination of the example is the easiest to distinguish)
.

In addition, in the embodiment, the initial resistance value and the maximum correctable resistance value are
However, as long as the resistance value range is correctable, it can be one, three or more (for example, the value for single cut and the value for L cut, respectively). display, etc.).

Further, in this example, a two-electrode type adjustment rectangular chip resistor was prototyped, but this can also be applied to a multi-electrode type.

Further, in this embodiment, the display was performed using glass on the top surface of the rectangular chip resistor for adjustment, but it may be displayed on any surface of the casing, and the display method is not limited (however, the top surface is most practical).

Effects of the Invention As described in Section 2, according to the present invention, there is no need to check the resistance value before mounting, which was complicated in conventional square chip resistors for adjustment, and instead, the display part can be easily checked visually using a magnifying glass, etc. By doing this, you can check the adjustable resistance value range. Furthermore, there is an advantage that mechanical inspection can be performed using pattern recognition or the like.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a perspective view and a cross-sectional view, respectively, showing the structure of a rectangular chip resistor for adjustment according to an embodiment of the present invention;
FIG. 3 is a plan view of a main part showing a mounting state of the rectangular chip resistor for adjustment according to the present invention, and FIG. 4 is a sectional view of a conventional rectangular chip resistor for adjustment. 1...96 alumina substrate, 2...Top electrode layer, 3...End electrode layer, 4...Resistance layer, 5... Glass layer, 6... Display section, 7... Ni plating layer, 8... δ b plating layer.

Claims (4)

[Claims] (1) A rectangular chip resistor for adjustment, characterized by having a display section on the casing surface that specifies the adjustable resistance value range. (2) The rectangular chip resistor for adjustment according to claim 1, wherein the display section clearly indicates the initial resistance value and the maximum adjustable resistance value. (3) The rectangular chip resistor for adjustment according to claim 1, wherein the display section clearly indicates the initial resistance value and the adjustable resistance value magnification. (4) an insulating substrate, a top electrode layer on the insulating substrate, a resistance layer overlapping a part of the top electrode layer, a glass layer completely covering the resistance layer, and a glass provided on the resistance layer. A rectangular chip for adjustment, characterized in that it is composed of a display part that specifies an adjustable resistance value range, and an end face electrode layer provided on the end face of an insulating substrate so as to overlap a part of the upper face electrode layer. Resistor.