JPH0963805A - Square chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square chip resistor which has a low resistance and is excellent in resistance precision. SOLUTION: The square chip resistor consists of the following: a pair of thick film resistor layers 12 formed on an upper surface of a square board 11, thick film upper surface electrode layers 13 electrically connected with the thick film resistor layers 12, and a pair of thick film end surface electrode layers 14 which connect a plurality of resistance elements in parallel. Thereby, a square chip resistor which has a low resistance and is excellent in resistance precision is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular chip resistor used in various electronic circuits.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of electronic equipment, the demand for surface-mounted components has increased in order to reduce the mounting area of electronic components. Among them, there is a strong demand for high precision products as an alternative to the conventional semi-fixed volume for the rectangular chip resistor. For example, a rectangular chip resistor having low resistance and excellent resistance value accuracy is one of the requirements for detecting current in a power supply circuit.

A conventional rectangular chip resistor will be described below with reference to the drawings. FIG. 2 is a perspective view of a conventional rectangular chip resistor. In the figure, 1 is a rectangular substrate made of 96% alumina. Reference numeral 2 is a thick-film resistor layer made of ruthenium oxide-based glaze provided on each of opposite sides of the upper surface of the substrate 1. Reference numeral 3 denotes a thick film upper surface electrode layer made of an Ag-based glaze provided on the upper surface of the substrate 1 so as to be electrically connected to the thick film resistor layers 2 provided on the respective side portions of the substrate 1. Reference numeral 4 is a thick film end face electrode layer made of Ag-based glaze provided on each end face of the substrate 1 so as to be electrically connected to the thick film resistor layer 2. Further, the thick film resistor layer 2 covers the substrate 1 so as to cover it.
A thick film protective film layer (not shown) made of lead borosilicate glass is provided on the upper surface, and an electrode plating layer (not shown) made of nickel and solder is formed so as to cover the thick film upper surface electrode layer 3 and the thick film end surface electrode layer 4. )) And.

[0004]

However, the above-mentioned conventional rectangular chip resistor has a low resistance value even if an attempt is made to improve the resistance value accuracy of a low resistance value (particularly 1 Ω or less). However, there is a problem in that it is difficult to obtain the measurement accuracy of the resistance value measuring device itself due to the selection of the resistance value, and the improvement of the resistance value is limited due to the influence of the contact resistance between the measurement terminal and the electrode.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a rectangular chip resistor having low resistance and excellent resistance value accuracy.

[0006]

In order to achieve the above-mentioned object, the present invention provides a rectangular substrate, and a plurality of thick film resistor layers provided on respective side portions facing the upper surface of the substrate, A thick film upper surface electrode layer provided so as to be electrically connected to each of the thick film resistor layers, and a thick film end surface provided at an end surface of the substrate so as to be electrically connected to this thick film upper surface electrode layer. It is composed of an electrode layer.

[0007]

According to the present invention, a resistance value as a rectangular chip resistor is formed by a combined resistance value obtained by connecting a plurality of resistance elements in parallel with electrode layers.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A rectangular chip resistor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a rectangular chip resistor according to an embodiment of the present invention. In the figure, 11 is a rectangular substrate made of 96% alumina. Reference numeral 12 is a thick-film resistor layer made of ruthenium oxide-based glaze, which is provided on each of four opposite sides of the upper surface of the substrate 11. Thirteen
Is a thick film upper surface electrode layer made of an Ag-based glaze provided so as to be electrically connected to the thick film resistor layers 12 respectively provided at four positions on the side facing the upper surface of the substrate 11. . Reference numeral 14 is a thick film end face electrode layer provided on each end face of the substrate 11 so as to be electrically connected to the four thick film resistor layers 12 provided on the upper face of the substrate 11. Further, the four thick film resistor layers 12 are covered with a thick film protective film (not shown) made of lead borosilicate glass so as to cover them, and the thick film resistor layer 12 and the thick film end face electrode layer 14 are covered.
Is composed of an electrode plating layer (not shown) covered with nickel and solder so as to cover them.

The manufacturing method of the rectangular chip resistor configured as described above will be described below.

First, 96% excellent in heat resistance and insulation.
On the surface of the substrate 11 having alumina, an electrode paste containing Ag as a main component was screen-printed on each of four opposite sides of the upper surface of the substrate 11 and baked at 850 ° C. to form four thick film upper electrode layers 13. Form.

Next, a ruthenium oxide glaze resistance paste is printed on the upper surface of the substrate 11 between the respective thick film upper surface electrode layers 13 facing each other, and baked at 850 ° C. to form four thick film resistor layers 12. .

Next, if necessary, the individual resistance values of the thick film resistor layer 12 are corrected to predetermined values by laser trimming.

Next, in order to protect the thick film resistor layer 12 whose resistance value has been corrected, a lead borosilicate glass paste is screen-printed and baked at 600 ° C. to form a protective film layer (not shown). . At this time, the four thick film resistor layers 12 connected in parallel are covered with one pattern.

Next, A is formed on the end surface of the substrate 11 so as to be electrically connected to the thick film upper surface electrode layer 13 provided on the upper surface of the substrate 11.
An electrode paste of g-based glaze is applied by a roller and baked at 600 ° C. to form the thick film end face electrode layer 14. At this time, the thick film end face electrode layers 14 are formed so that the four thick film upper surface electrode layers 13 connected to the four thick film resistor layers 12 are connected in parallel.

Finally, the exposed thick film upper surface electrode layer 13
In order to prevent electrode erosion during soldering of the thick film end face electrode layer 14 and to ensure reliability during soldering, a plating layer of Ni and Sn-Pb is formed by electroplating to manufacture a rectangular chip resistor. To do.

Through the above steps, a square chip resistor according to the present invention was prototyped. In this rectangular chip resistor of the present invention, a resistance material was selected so that each resistance element was 1Ω, and the resistance value was corrected. Therefore, by connecting four resistance elements in parallel, 0.25Ω can be formed. Conventionally, the resistance value accuracy of 0.25Ω was limited to about ± 5%, but according to the present invention, since each resistance element is 1Ω and the region where the accuracy of ± 1% is obtained, the combined resistance value 0 0.25 Ω
Within ± 1% was achieved. Also, the temperature coefficient of resistance is 0.25
Although it was Ω, it was + 600ppm / ° C in the past,
It could be +100 ppm / ° C.

In this embodiment, the plurality of resistance elements are connected in parallel by the thick film end face electrode layer, but the resistance elements may be connected in parallel other than the end face electrode layer, and the resistance value higher than the target resistance value may be used. A low resistance value may be realized by connecting resistance elements having different values in parallel.

Further, although the thick film resistance element has been described in the present embodiment, the constituent material is not limited, and the same applies to the thin film resistance element.

Although the resistance elements connected in parallel are covered with the protective film having one pattern, the patterns may be formed individually.

Although four thick film resistor layers and thick film upper surface electrode layers have been described in the present embodiment, a plurality of thick film resistor layers and thick film upper surface electrode layers provided by desired resistors are provided. Good.

[0022]

As described above, according to the present invention, a resistance value as a rectangular chip resistor is formed by a combined resistance value obtained by connecting a plurality of resistance elements in parallel in the electrode layer. When the same resistance value as the resistance value formed by one independent resistor from the past is formed, the resistance value of each resistance element becomes higher than in the conventional case, and it is less likely to be affected by the contact resistance. If the measurement accuracy in the resistance value correction process is easy to obtain and the resistance value accuracy of each resistance element is good, the accuracy of these combined resistance values will be even better. It is possible to provide a rectangular chip resistor that can achieve the above.

Further, since the resistance material for forming the resistor has a higher area resistance value than the conventional one,
A material having a high resistance is better than a material having a low resistance.
Since it is easy to limit the temperature coefficient of resistance, it is possible to provide a rectangular chip resistor capable of improving the temperature coefficient of resistance as well as the accuracy of the resistance value.

Further, since the resistance elements are connected in parallel,
It is possible to provide a rectangular chip resistor having good life characteristics because the load concentration points (hot spots) in the resistor when a load is applied are dispersed instead of being concentrated at one point as in the conventional case.

[Brief description of drawings]

FIG. 1 is a perspective view of a rectangular chip resistor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a conventional rectangular chip resistor.

[Explanation of symbols]

 11 Substrate 12 Thick Film Resistor Layer 13 Thick Film Top Electrode Layer 14 Thick Film End Face Electrode Layer

Claims (1)

[Claims] 1. A rectangular substrate, and a plurality of thick film resistor layers provided on respective sides facing the upper surface of the substrate,
A thick film upper surface electrode layer provided on the substrate so as to be electrically connected to each of the plurality of thick film resistor layers, and the thick film upper surface electrode layer of the substrate so as to be electrically connected to each other. A rectangular chip resistor comprising a thick film end face electrode layer provided on the end face.