JP2007036012A - Chip resistor for large electric power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To plan a large electrification of a chip resistor and an improvement of an anti-surge property in the chip resistor constituted by forming a resistive film and terminal electrodes corresponding to both ends of the resistive film on an insulating substrate. <P>SOLUTION: While forming terminal electrodes 3 for a solder connection at both right and left sides 2' in an insulating substrate 2 made into a rectangular form, at a portion between the both terminal electrodes out of a top face in the insulating substrate, there are arranged in parallel plural resistive films 4 whose both ends conduct to the both terminal electrodes. Each of these resistive films 4 is constituted to be a zigzag form from a terminal electrode at one end toward a terminal electrode at the other end. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chip resistor configured to cope with high power among chip resistors formed by forming a resistance film on the surface of a chip-type insulating substrate.

  Conventionally, this type of chip resistor A is described in, for example, Patent Document 1 and the like, and as shown in FIG. 4, the upper surface of an insulating substrate A1 having a rectangular length of L and a width of W is used. Further, the resistance film A2 is formed to extend in the length direction of the insulating substrate A1, while the terminal electrodes A3 for the both ends of the resistance film A2 are formed on both end surfaces A1 ′ in the length direction of the insulating substrate A1. The both terminal electrodes A3 are mounted on a printed circuit board or the like by soldering.

However, in FIG. 3, symbol A4 is a trimming groove for adjusting the resistance value.
JP 11-273901 A

  The conventional chip resistor A shown in FIG. 4 has a configuration in which one resistive film A2 is provided between a pair of left and right terminal electrodes A3 soldered to a printed circuit board or the like. The power applied to both terminal electrodes A3 is concentrated on the resistance film A2 in one of them, and the temperature rise in the one resistance film A2 becomes large, so that there is a problem that it cannot be applied for high power.

  In this case, as shown in FIG. 5, in the insulating substrate B1 having the same rectangular size (the same length dimension L and the same width dimension W) as described above, the insulating substrate B1 is formed on the upper surface thereof. A plurality of resistance films B2 extending in the width direction are formed in parallel in the length direction, while the resistance films B2 are formed on both left and right side surfaces in the length direction of the insulating substrate B1, that is, on both left and right long side surfaces B1 '. By configuring the multiple chip resistors B to form a common terminal electrode B3 for B2, the applied power can be distributed to the plurality of resistive films B2, so that the chip resistor A shown in FIG. High power can be achieved with the same rectangular size.

  However, on the other hand, each resistive film B2 in this multiple chip resistor B has a length extending in the width direction of the insulating substrate B1, and therefore the length of the current path is the chip resistor of FIG. Since it is much shorter than the case of A, there is a problem that the rate of change in resistance value is large when a surge voltage generated due to the influence of static electricity or power supply noise is applied and the surge resistance is low.

  An object of the present invention is to provide a chip resistor that is suitable for high power and has high surge resistance.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A plurality of terminal electrodes for solder connection are formed on both the left and right side surfaces of the rectangular insulating substrate, while both ends of the upper surface of the insulating substrate are electrically connected to both terminal electrodes. The resistive films are formed side by side, and each of the resistive films is configured to be folded from the terminal electrode at one end to the terminal electrode at the other end.
It is characterized by that.

Claim 2
“In the first aspect of the present invention, the insulating substrate is rectangular, and the terminal electrodes are formed on both left and right longitudinal sides of the insulating substrate.”
It is characterized by that.

  With the configuration described in claim 1, since the applied power to both terminal electrodes is distributed to a plurality of resistance films, it can be adapted to a large power, while each of the resistance films Since the length of the current path is long due to zigzag folding, the rate of change in resistance when a surge voltage is applied is reduced, and surge resistance can be improved.

  In particular, according to the configuration described in claim 2, it is possible to increase the power and improve the surge resistance without changing the size of the rectangle.

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

  1 to 3 show a chip resistor 1 according to an embodiment of the present invention.

  The chip resistor 1 includes an insulating substrate 2 made of a heat-resistant insulator such as ceramic. The insulating substrate 2 is formed in a rectangular shape having a length dimension L and a width dimension W.

  Terminal electrodes 3 for solder connection are formed so as to extend along the longitudinal side surface 2 'on the left and right side surfaces in the length direction of the insulating substrate 2, that is, both the left and right longitudinal side surfaces 2'.

  On the other hand, in the upper surface of the insulating substrate 2, a plurality of resistance films 4 (the figure shows the case of three) are provided in the length direction of the insulating substrate 2 between the terminal electrodes 3. The resistance films 4 are formed in parallel at appropriate intervals. Both ends of the resistance films 4 are electrically connected to the terminal electrodes 3.

  Moreover, each of the resistance films 4 includes a plurality of (two in the drawing) entering grooves 5 from one side surface 4 ′ and a plurality of (two in the drawing) from the other side surface 4 ″. By alternately providing the entering grooves 6, it is configured to be folded in a zigzag manner.

  A cover coat 7 is formed on the upper surface of the insulating substrate 2 to cover the entire resistance film 4.

  Each of the resistance films 4 may be formed in a zigzag manner by providing the entry grooves 5 and 6 at the same time when the resistance film 4 is formed by screen printing. A part or the whole may be formed into a zigzag fold by engraving by processing such as laser beam irradiation after screen printing.

  In the above-described configuration, the applied power to both terminal electrodes 3 is dispersed in each of the plurality of resistance films 4, so that it can be adapted to high power, while each of the resistance films 4 is folded in a zigzag manner. As a result, since the length of the current path is long, the rate of change in resistance value when a surge voltage is applied is reduced, and surge resistance can be improved.

  6 and 7 are the same as the chip resistor 1 according to the present invention shown in FIGS. 1 to 3 and the conventional chip resistor A shown in FIG. 4 and the multiple chip resistors B shown in FIG. The results of experiments comparing the performance of rectangular sizes (with the same length dimension L and the same width dimension W) are shown.

  That is, FIG. 6 shows a temperature rise on the surface of the resistance film when power is applied to both terminal electrodes. In the case of the conventional chip resistor A, the temperature rise is indicated by a one-dot chain line C. In contrast, in the case of the chip resistor 1 according to the present invention and the multiple chip resistor B according to the present invention, the temperature rise can be greatly reduced as shown by the solid line D.

  Next, FIG. 7 shows an electrostatic breakdown test (evaluation of surge resistance). In the case of the multiple chip resistor B, the change in the resistance value is significant as shown by the alternate long and short dash line E. On the other hand, in the case of the chip resistor 1 according to the present invention and the conventional chip resistor A, the change in the resistance value can be greatly reduced as indicated by the solid line F.

  From these experiments, it has been clarified that according to the present invention, the power can be increased and the surge resistance can be improved under the same rectangular size as the conventional chip resistor 1.

  In the case of the present embodiment, at least one recess 8 is provided on the left and right longitudinal side surfaces 2 ′ of the insulating substrate 2, and the terminal electrode 3 is formed on the inner surface of the recess 8. When soldering to the printed circuit board 9 or the like, the solder fret is constructed so as to rise up to the portion in the recess 8 so as to improve the soldering strength.

It is a top view of the chip resistor by an embodiment of the invention. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a perspective view which shows the conventional chip resistor. It is a perspective view which shows the conventional multiple chip resistor. It is a figure which shows the temperature rise in the surface of a resistance film. It is a figure which shows the result of an electrostatic breakdown test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chip resistor 2 Insulation board | substrate 2 'Long side surface 3 Terminal electrode 4 Resistive film | membrane 5,6 Entering groove | channel 7 Cover coat

Claims (2)

  A terminal electrode for solder connection is formed on both the left and right side surfaces of the rectangular insulating substrate, and a plurality of resistors whose both ends are connected to both terminal electrodes in the portion between the terminal electrodes on the upper surface of the insulating substrate. A high-power chip resistor characterized in that films are formed side by side, and each of the resistive films is formed so as to be folded from a terminal electrode at one end thereof toward a terminal electrode at the other end.   2. The high-power chip resistor according to claim 1, wherein the insulating substrate is rectangular and the terminal electrodes are formed on both left and right longitudinal sides of the insulating substrate.

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