JP2024091146A - Chip Resistors - Google Patents

Abstract

[Problem] To provide a chip resistor with high withstand voltage. [Solution] A resistor 5 of a chip resistor 1 has a resistance value adjustment section 12 provided between a first connection section 31 and a second connection section 32 on a surface 21 of an insulating substrate 2. A meandering forming section 15 is formed in the resistance value adjustment section 12 to make the resistance value adjustment section 12 into a meandering shape. The meandering forming section 15 has three or more odd number of trimming grooves (16, 17, 18). Each of the trimming grooves (16, 17, 18) has a straight line portion extending from a second edge 14 of the resistance value adjustment section 12 along a second direction perpendicular to a first direction in which the first connection section 31 and the second connection section 32 are aligned. Of the three or more odd number of trimming grooves (16, 17, 18), the trimming grooves (17, 18) other than the trimming groove (16) located at the center in the first direction are shorter than the adjacent trimming groove (16) located at the center in the first direction. [Selected figure] Figure 2

Description

The present disclosure relates generally to chip resistors, and more specifically to chip resistors having a pair of electrodes and a resistor body.

Patent document 1 discloses a chip resistor in which a linear trimming groove is formed in the rectangular portion of the resistor formed on an insulating substrate.

JP 2010-135358 A

In the chip resistor described in Patent Document 1, the trimming groove forms a serpentine pattern in the rectangular portion of the resistor. The trimming groove is formed, for example, using a laser. In addition, in the chip resistor described in Patent Document 1, two parallel trimming grooves are formed to finely adjust the resistance value.

On the other hand, when a laser is used to form the trimming groove, there are technical limitations to widening the width of the trimming groove. Therefore, it is difficult to increase the voltage resistance of the trimming groove, and as a result, the voltage resistance of the trimming groove may become the voltage limit of the chip resistor.

The objective of this disclosure is to provide a chip resistor with high voltage resistance.

A chip resistor according to one aspect of the present disclosure includes a substrate, a pair of electrodes, and a resistor. The pair of electrodes are provided on both ends of one surface of the substrate. The resistor is provided between the pair of electrodes on the one surface of the substrate. The resistor has a pair of connection parts respectively connected to the pair of electrodes, and a resistance value adjustment part provided between the pair of connection parts. The resistance value adjustment part has a meandering forming part for forming the resistance value adjustment part into a meandering shape. The meandering forming part has three or more odd number of trimming grooves. Each of the three or more odd number of trimming grooves has a straight line part extending from the groove starting edge of the resistance value adjustment part along a second direction perpendicular to the first direction in which the pair of connection parts are arranged. The three or more odd number of trimming grooves, other than the trimming groove at the center in the first direction, are shorter than the adjacent trimming groove at the center side in the first direction.

This disclosure provides a chip resistor with high voltage resistance.

FIG. 1 is a schematic cross-sectional view of a chip resistor according to a first embodiment of the present disclosure. FIG. 2 is a schematic top view of the chip resistor. FIG. 3 is a graph showing the change in potential difference across each groove with respect to the change in the ratio of the length of the trimming grooves on both sides to the length of the central trimming groove. FIG. 4 is a schematic top view of a chip resistor according to the second embodiment of the present disclosure. FIG. 5 is a schematic top view of a chip resistor according to the third embodiment of the present disclosure. FIG. 6 is a schematic top view of a chip resistor according to a fourth embodiment of the present disclosure. FIG. 7 is a schematic top view of a chip resistor according to a fifth embodiment of the present disclosure. FIG. 8 is a schematic top view of a chip resistor according to the sixth embodiment of the present disclosure.

The chip resistor according to the embodiment will be described below with reference to the drawings. Each figure described in the following embodiment is a schematic diagram, and the ratio of the size and thickness of each component does not necessarily reflect the actual dimensional ratio. Furthermore, the configuration described in the following embodiment is merely one example of the present disclosure. The present disclosure is not limited to the following embodiment, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

First Embodiment
(1) Basic Configuration of Chip Resistor A first embodiment will be described below with reference to Fig. 1 and Fig. 2. The first embodiment discloses a chip resistor 1 in which a meandering groove is formed in a resistor element.

The chip resistor 1 is, for example, a chip resistor for surface mounting (SMT: Surface Mount Technology) that is mounted on the surface (mounting surface) of a printed circuit board using a surface mounter. In this embodiment, as an example, the chip resistor 1 is a thick-film chip resistor.

As shown in Figures 1 and 2, the chip resistor 1 has an insulating substrate 2, a first upper surface electrode 3, a second upper surface electrode 4, and a resistor 5. As shown in Figure 1, the chip resistor 1 further has a first lower surface electrode 33, a second lower surface electrode 34, a first end surface electrode 35, a second end surface electrode 36, a pair of first plating layers 37, and a pair of second plating layers 38. As shown in Figure 1, the chip resistor 1 further has a glass protective film 41 and a resin protective film 42.

(2) Insulating Substrate The insulating substrate 2 is made of _alumina containing, for example, 96% _Al2O3 , and has a rectangular shape (rectangular when viewed from above). Hereinafter, the left-right direction in Fig. 1 and Fig. 2 is referred to as a longitudinal direction D1 (an example of a first direction), and the up-down direction in Fig. 2 is referred to as a lateral direction D2 (an example of a second direction). Furthermore, the right side in Fig. 1 and Fig. 2 is referred to as a longitudinal first side, the left side in Fig. 1 and Fig. 2 is referred to as a longitudinal second side, the upper side in Fig. 2 is referred to as a lateral first side, and the lower side in Fig. 2 is referred to as a lateral second side.

The longitudinal direction D1 and the lateral direction D2 are perpendicular to each other. Note that the concept of perpendicular here includes approximately perpendicular, and includes the range of 90°±10°.

(3) Top Electrode, Bottom Electrode and Side Electrode The first top electrode 3 and the second top electrode 4 are provided at both longitudinal ends of the surface 21 of the insulating substrate 2, and are formed by printing and firing a thick-film material containing a metal such as silver.

The first lower surface electrode 33 and the second lower surface electrode 34 are provided at both longitudinal ends of the rear surface 22 of the insulating substrate 2, and are formed by printing and firing a thick-film material containing a metal such as silver. The first lower surface electrode 33 and the second lower surface electrode 34 correspond to the first upper surface electrode 3 and the second upper surface electrode 4, respectively.

The first end surface electrode 35 and the second end surface electrode 36 are provided on a pair of end surfaces 23 on both sides in the longitudinal direction of the insulating substrate 2, respectively. The first end surface electrode 35 and the second end surface electrode 36 are, for example, sputtered films made of NiCr. That is, the first end surface electrode 35 and the second end surface electrode 36 are formed (deposited) on the left-right end surfaces 23 of the insulating substrate 2 by sputtering. The first end surface electrode 35 electrically connects the first upper surface electrode 3 and the first lower surface electrode 33. The second end surface electrode 36 electrically connects the second upper surface electrode 4 and the second lower surface electrode 34.

(4) Resistor (4-1) Overview of Resistor The resistor 5 is formed on the surface 21 of the insulating substrate 2 between the first upper surface electrode 3 and the second upper surface electrode 4, and is connected to the first upper surface electrode 3 and the second upper surface electrode 4. The resistor 5 is formed by printing a thick film material made of, for example, about 10 wt % lead ruthenate, about 53 wt % glass, and about 37 wt % solvent on the surface 21 of the insulating substrate 2, and then baking it.

The resistor 5 has a resistance value adjustment portion 12, a first connection portion 31, and a second connection portion 32.

The resistance value adjustment section 12 is disposed at the longitudinal center of the surface 21 of the insulating substrate 2, that is, at a distance between the first upper surface electrode 3 and the second upper surface electrode 4. More specifically, the resistance value adjustment section 12 is provided between the first connection section 31 and the second connection section 32. The resistance value adjustment section 12 is a section where the resistance value of the resistor 5 is adjusted by laser trimming as described below. The edge of the resistance value adjustment section 12 on the first side in the short side direction is the first edge 13, and the edge on the second side in the short side direction is the second edge 14 (an example of a groove starting edge).

The first connection portion 31 and the second connection portion 32 are arranged in the longitudinal direction D1 (first direction). The first connection portion 31 includes a first rectangular portion 6, a second rectangular portion 7, and a third rectangular portion 8 (an example of a connection portion). The first rectangular portion 6 is connected to the first side portion of the first upper surface electrode 3 in the short side direction and extends to the first side in the longitudinal direction. The second rectangular portion 7 extends from the tip of the first rectangular portion 6 to the second side in the short side direction. The third rectangular portion 8 extends from the tip of the second rectangular portion 7 to the first side in the longitudinal direction and is connected to the end portion of the resistance value adjustment portion 12 in the short side direction second side (the end portion on the second edge 14 side). The third rectangular portion 8 has an edge 49 (an example of an edge) on the first side in the short side direction. The edge 49 is an edge opposite to the second edge 14 in the short side direction D2.

The second connection portion 32 includes a fourth rectangular portion 9, a fifth rectangular portion 10, and a sixth rectangular portion 11 (an example of a connection portion). The fourth rectangular portion 9 is connected to the first short-side portion of the second upper surface electrode 4 and extends to the second long-side. The fifth rectangular portion 10 extends from the tip of the fourth rectangular portion 9 to the second short-side side. The sixth rectangular portion 11 extends from the tip of the fifth rectangular portion 10 to the second long-side side and is connected to the end portion of the resistance value adjustment portion 12 on the second short-side side (the end portion on the second edge 14 side). In the above-mentioned configuration, the sixth rectangular portion 11 is provided in the vicinity of the second edge 14 of the resistance value adjustment portion 12. The sixth rectangular portion 11 has an edge 50 (an example of an edge) on the first short-side side. The edge 50 is an edge opposite to the second edge 14 in the short-side direction D2. The short-side position of edge 49 of third rectangular section 8 and edge 50 of sixth rectangular section 11 is the voltage reference position 51.

(4-2) Resistance Adjustment Section The resistance adjustment section 12 is formed with a meandering forming section 15 for forming the resistance adjustment section 12 into a meandering shape. The resistor 5 has a meandering shape folded back three times in a direction parallel to the short-side direction D2 of the insulating substrate 2. Specifically, the first rectangular section 6, the second rectangular section 7, the third rectangular section 8, and the resistance adjustment section 12 form a first turn folded back to the first side in the short-side direction. In addition, the fourth rectangular section 9, the fifth rectangular section 10, the sixth rectangular section 11, and the resistance adjustment section 12 form a second turn folded back to the first side in the short-side direction. In addition, the resistance adjustment section 12 forms a third turn folded back to the second side in the short-side direction, as described later.

The meandering portion 15 has three trimming grooves. Specifically, the meandering portion 15 has a first trimming groove 16 (a central groove), a second trimming groove 17 (an example of a side groove), and a third trimming groove 18 (an example of a side groove). The first trimming groove 16, the second trimming groove 17, and the third trimming groove 18 extend parallel to the short direction D2 (an example of a second direction) from the second edge 14 of the resistance value adjustment portion, and form a straight portion.

The first trimming groove 16 is located in the longitudinal center of the three trimming grooves. The second trimming groove 17 is located on the second longitudinal side of the first trimming groove 16. The third trimming groove 18 is located on the first longitudinal side of the first trimming groove 16.

The first trimming groove 16 extends further in the short direction D2 than the second trimming groove 17 and the third trimming groove 18. In other words, the distal end portion (tip surface) of the first trimming groove 16 in the extension direction is located on the first side in the short direction than the distal end portions (tip surfaces) of the second trimming groove 17 and the third trimming groove 18 in the extension direction.

The second trimming groove 17 and the third trimming groove 18 have the same short-side length, that is, the distal end portions (tip surfaces) of both in the extension direction are at the same position in the short-side direction D2.

The above configuration allows the potential difference on both sides of each trimming groove in the meandering formation section 15 to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed. Even if the number of grooves is increased to three or more, if all the grooves are the same length, there is little change in the potential difference on both sides of each groove, and therefore the withstand voltage is not improved.

As shown in FIG. 2, if the second direction length from the voltage reference position 51 to the tip of the first trimming groove 16 is a1, and the second direction length from the voltage reference position 51 to the tips of the second trimming groove 17 and the third trimming groove 18 is b1, then 0.42≦b1/a1<1.00 holds. In this case, the potential difference on both sides of each trimming groove can be reduced compared to the conventional example of two trimming grooves, so voltage breakdown in the groove portion is less likely to occur, and characteristic abnormalities can be suppressed.

In this embodiment, it is preferable that b1 = (2 x a1) / 3 is satisfied. This condition is obtained from the formula b1 = (2n x a1) / (2n + 1). In the above formula, 2n + 1 (n is a positive integer) is the number of trimming grooves. When the above formula is satisfied, the potential difference on both sides of the trimming groove can be reduced to approximately 1/(2n + 1) compared to the case of two trimming grooves.

(5) Glass Protective Film Glass protective film 41 is a film for protecting resistor element 5. As shown in FIG. 1, glass protective film 41 covers the entire area (whole) of resistor element 5. Glass protective film 41 is made of, for example, lead oxide glass. Glass protective film 41 is formed (deposited) by, for example, screen printing. Note that glass protective film 41 is not limited to lead oxide glass, and may be, for example, silicate glass.

(6) Resin Protective Film Resin protective film 42 is made of, for example, epoxy resin, and covers the entire area (whole) of glass protective film 41. Resin protective film 42 penetrates into first trimming groove 16, second trimming groove 17, and third trimming groove 18. Resin protective film 42 is formed (deposited) by, for example, applying epoxy resin by screen printing and then thermally curing the epoxy resin.

(7) First Plating Layer The pair of first plating layers 37 is made of, for example, nickel (Ni) plating. The pair of first plating layers 37 cover the first end surface electrode 35 and the second end surface electrode 36 at both longitudinal ends of the insulating substrate 2, respectively.

(8) Second Plating Layer The pair of second plating layers 38 is made of, for example, tin (Sn) plating. The pair of second plating layers 38 covers the pair of first plating layers 37 at both longitudinal ends of the insulating substrate 2.

(9) Characteristics Using Fig. 3, the change in the potential difference on both sides of each groove with respect to the change in the ratio (%) of the length of the second trimming groove 17 and the third trimming groove 18, which are side grooves, to the length of the first trimming groove 16, which is the central groove, is described. This result was obtained by a simulation in which 800 V was applied to the resistor 5. Here, the potential difference on both sides of the groove means the potential difference between the conductor portions on both sides of each trimming groove. In the case of the conventional two trimming grooves, the minimum value of the potential difference on both sides of the groove was 176 V.

In FIG. 3, the line connecting multiple points (△) indicates the potential difference on both sides of the first trimming groove 16, and the line connecting multiple points (◯) indicates the potential difference on both sides of the second trimming groove 17 and the third trimming groove 18. Furthermore, the straight line 61 indicates 176V, which is the minimum value of the conventional potential difference on both sides of the groove. As is clear from FIG. 3, when the above ratio is small, the potential difference on both sides of the first trimming groove 16 is 176V or more, but as the above ratio increases, the potential difference on both sides of the first trimming groove 16 decreases, and when the ratio is 42% or more, the potential difference on both sides of the groove becomes less than 176V. Also, when the above ratio is small, the potential difference on both sides of the second trimming groove 17 and the potential difference on both sides of the third trimming groove 18 are small, but as the above ratio increases, the potential difference on both sides of the second trimming groove 17 and the potential difference on both sides of the third trimming groove 18 increase. However, even if the above ratio approaches 100%, the potential difference between both sides of the second trimming groove 17 and the potential difference between both sides of the third trimming groove 18 is less than 176 V.

From the above, it was found that if the above ratio is 42% or more but less than 100%, a potential difference even smaller than the conventional minimum potential difference between both sides of the groove can be obtained. Furthermore, it is preferable that the above ratio is in the range of 60 to 80%, and more preferably in the range of 65 to 75%. In that case, the potential difference between both sides of the groove for all trimming grooves can be made lower than 120 V.

(10) Manufacturing Method of Chip Resistor Hereinafter, a manufacturing method of the chip resistor 1 will be described. However, for the sake of simplicity, only the formation of the first upper surface electrode 3, the second upper surface electrode 4, and the resistor 5 will be described.

First, electrode paste is screen-printed on both longitudinal ends of an insulating substrate 2 made of alumina, and then fired at 850°C to form a first upper electrode 3 and a second upper electrode 4.

Next, a resistive paste is screen-printed between the first upper electrode 3 and the second upper electrode 4, and then fired at 850°C to form the resistor 5.

Next, the meandering forming portion 15 is formed by laser trimming to give the resistance value adjustment portion 12 a meandering shape. This gives the resistor 5 a meandering shape with three turns.

Second Embodiment
A chip resistor 1A according to the second embodiment will be described with reference to Fig. 4. Note that the basic configuration of the chip resistor 1A is the same as that of the chip resistor 1 according to the first embodiment, so the following description will focus on the differences.

A meandering forming portion 15A is formed in the resistance value adjustment portion 12A of the resistor 5A. The meandering forming portion 15A has a trimming groove for forming the resistance value adjustment portion 12A into a meandering shape. Specifically, the meandering forming portion 15A has a first trimming groove 16A (an example of a central groove), a second trimming groove 17A (an example of a side groove), and a third trimming groove 18A (an example of a side groove). The first trimming groove 16A, the second trimming groove 17A, and the third trimming groove 18A extend parallel to the short direction D2 from the second edge 14A (an example of a groove starting edge) of the resistance value adjustment portion 12A, and are linear. The second trimming groove 17A is disposed on the second side of the first trimming groove 16A in the longitudinal direction. The third trimming groove 18A is disposed on the first side of the first trimming groove 16A in the longitudinal direction.

The first trimming groove 16A has a straight portion 16A1 extending from the second edge 14A of the resistance value adjustment portion 12A to the first side in the short side direction, and a folded portion 16A2 extending from the tip of the straight portion 16A1 on the first side in the short side direction in a folded direction (toward the second edge 14). The folded portion 16A2 has a folded portion that is semicircular in plan view in the thickness direction of the insulating substrate 2A, and a straight tip portion that folds back against the straight portion 16A1 and extends parallel to the straight portion 16A1.

The second trimming groove 17A has a straight portion 17A1 extending from the second edge 14A of the resistance value adjustment portion 12 to the first side in the short side direction, and a folded portion 17A2 extending from the tip of the straight portion 17A1 on the first side in the short side direction so as to bend in the folding direction. The folded portion 17A2 has a folded portion that is semicircular in shape when viewed from above in the thickness direction of the insulating substrate 2A, and a straight portion at the tip that is folded back from the straight portion 17A1 and extends parallel to the straight portion 17A1.

The third trimming groove 18A has a straight portion 18A1 extending from the second edge 14A of the resistance value adjustment portion 12 to the first side in the short side direction, and a folded portion 18A2 extending from the tip of the straight portion 18A1 on the first side in the short side direction in a folded direction. The folded portion 18A2 has a folded portion that is semicircular in shape when viewed from above in the thickness direction of the insulating substrate 2, and a straight portion at the tip that is folded back from the straight portion 18A1 and extends parallel to the straight portion 18A1.

As described above, the folding direction of the folded portion 17A2 of the second trimming groove 17 and the folded portion 18A2 of the third trimming groove 18A is toward the first trimming groove 16A, and the grooves do not intersect with each other.

The first trimming groove 16A extends further in the short direction D2 than the second trimming groove 17A and the third trimming groove 18A. In other words, the distal end of the first trimming groove 16A in the extension direction (the apex of the folded portion) is located on the first side in the short direction than the distal end of the second trimming groove 17A and the third trimming groove 18A in the extension direction (the apex of the folded portion).

The short-side lengths of the second trimming groove 17A and the third trimming groove 18A are the same, that is, the most distal portions of both in the extension direction (the apex of the folded portion) are at the same position in the short-side direction D2.

The above configuration allows the potential difference between both sides of each trimming groove in the meandering formation section 15 to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

In the above configuration, since each trimming groove has a folded portion, microcracks are unlikely to occur at the tip end of the trimming groove in the extension direction (the apex of the folded portion). In particular, since each folded portion has at least a part of a circular arc portion, current concentration at the corner portion at the tip of the folded portion can be alleviated, improving load characteristics.

More specifically, because the microcracks at the tip of the first trimming groove 16A are oriented in the same direction as the current path, the resistance value hardly changes even when the microcracks grow, i.e., the resistance value precision and reliability are improved. Furthermore, the resistance value fluctuations when the microcracks at the tips of the second trimming groove 17A and the third trimming groove 18A grow can be reduced, improving the resistance value precision and reliability.

Furthermore, since the folded portion 17A2 of the second trimming groove 17A and the folded portion 18A2 of the third trimming groove 18 are folded toward the first trimming groove 16 in the longitudinal direction D1, the locations where microcracks occur at the tips of the second trimming groove 17A and the third trimming groove 18A can be positioned in locations where almost no current flows. As a result, the resistance value precision and reliability are further improved.

In the second embodiment described above, all trimming grooves have turned-up portions, but in a modified example, only some of the trimming grooves may have turned-up portions. Specifically, it is preferable that the central groove has a turned-up portion, but the other trimming grooves do not have to have turned-up portions.

Third Embodiment
A chip resistor 1B according to the third embodiment will be described with reference to Fig. 5. Note that the basic configuration of the chip resistor 1B is the same as that of the chip resistor 1 according to the first embodiment, so the following description will focus on the differences.

The resistor 5B has a resistance value adjustment portion 12B, a first connection portion 6B, and a second connection portion 9B.

The resistance adjustment section 12B is disposed at the longitudinal center of the surface 21B of the insulating substrate 2B, that is, between the first upper surface electrode 3B and the second upper surface electrode 4B. The resistance adjustment section 12B is a portion where the resistance value of the resistor 5B is adjusted by laser trimming. The edge on the first longitudinal side of the resistance adjustment section 12B is the first edge 13B, and the edge on the second longitudinal side is the second edge 14B (an example of a groove starting edge).

The first connection portion 6B and the second connection portion 9B are aligned in the short direction D2 (an example of a first direction). The first connection portion 6B is connected to a first short side portion of the first upper surface electrode 3B, extends to the first longitudinal side, and is connected to the resistance value adjustment portion 12B. The second connection portion 9B is connected to a second short side portion of the second upper surface electrode 4, and extends to the second longitudinal side. The end of the second longitudinal side of the second connection portion 9B is connected to the resistance value adjustment portion 12B via the connection portion 11B.

The resistance value adjustment section 12B is formed with a meandering forming section 15B. The meandering forming section 15B has a trimming groove for forming the resistance value adjustment section 12B into a meandering shape. Specifically, the meandering forming section 15B has a first trimming groove 16B (an example of a central groove), a second trimming groove 17B (an example of a side groove), and a third trimming groove 18B (an example of a side groove). The first trimming groove 16B, the second trimming groove 17B, and the third trimming groove 18B extend parallel to the longitudinal direction D1 (an example of a second direction) from the second edge 14B of the resistance value adjustment section 12B, and form a straight section. The second trimming groove 17B is disposed on the first side in the short side direction of the first trimming groove 16B. The third trimming groove 18B is disposed on the second side in the short side direction of the first trimming groove 16B.

The resistor 5B has a serpentine shape folded back in a direction parallel to the longitudinal direction D1 of the insulating substrate 2B. Specifically, the first connection portion 6B and the serpentine forming portion 15B form a first turn that folds back to the second longitudinal side. Furthermore, the serpentine forming portion 15B, the connection portion 11B, and the second connection portion 9B form a second turn that folds back to the first longitudinal side.

The first trimming groove 16B extends further in the longitudinal direction D1 than the second trimming groove 17B and the third trimming groove 18B. In other words, the distal end portion (tip surface) of the first trimming groove 16B in the extension direction is located on the first longitudinal side of the distal end portions (tip surfaces) of the second trimming groove 17B and the third trimming groove 18B in the extension direction.

The longitudinal lengths of the second trimming groove 17B and the third trimming groove 18B are the same, that is, the distal ends (tip surfaces) of both of them in the extension direction are at the same position in the longitudinal direction D1.

The above configuration allows the potential difference between both sides of each trimming groove in the meandering forming portion 15B to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

Fourth Embodiment
A chip resistor 1C according to the fourth embodiment will be described with reference to Fig. 6. Note that the basic configuration of the chip resistor 1C is the same as that of the chip resistor 1B according to the third embodiment, so the following description will focus on the differences.

A meandering forming portion 15C is formed in the resistance value adjustment portion 12C of the resistor 5C. The meandering forming portion 15C has a trimming groove for forming the resistance value adjustment portion 12C into a meandering shape. Specifically, the meandering forming portion 15C has a first trimming groove 16C (an example of a central groove), a second trimming groove 17C (an example of a side groove), and a third trimming groove 18C (an example of a side groove). The first trimming groove 16C, the second trimming groove 17C, and the third trimming groove 18C extend parallel to the longitudinal direction D1 (an example of a second direction) and are linear. The second trimming groove 17C is disposed on the first side of the first trimming groove 16C in the short side direction. The third trimming groove 18C is disposed on the second side of the first trimming groove 16C in the short side direction.

The first trimming groove 16C has a straight portion 16C1 that extends from the second edge 14C (an example of a groove starting edge) of the resistance value adjustment portion 12C to the first side in the longitudinal direction, and a folded portion 16C2 formed at the end of the straight portion 16C1 on the first side in the longitudinal direction. The folded portion 16C2 has a folded portion that is semicircular in plan view from the thickness direction of the insulating substrate 2C, and a straight tip portion that folds back against the straight portion 16C1 and extends parallel to the straight portion 16C1.

The second trimming groove 17C has a straight portion 17C1 extending from the second edge 14C of the resistance value adjustment portion 12 to the first side in the longitudinal direction, and a folded portion 17C2 formed at the end of the straight portion 17C1 on the first side in the longitudinal direction. The folded portion 17C2 has a folded portion that is semicircular in plan view from the thickness direction of the insulating substrate 2C, and a straight tip portion that folds back against the straight portion 17C1 and extends parallel to the straight portion 17C1.

The third trimming groove 18C has a straight portion 18C1 extending from the second edge 14C of the resistance value adjustment portion 12 to the first side in the longitudinal direction, and a folded portion 18C2 formed at the end of the straight portion 18C1 on the first side in the longitudinal direction. The folded portion 18C2 has a folded portion that is semicircular in plan view from the thickness direction of the insulating substrate 2, and a straight tip portion that folds back against the straight portion 18C1 and extends parallel to the straight portion 18C1.

As described above, the folding direction of the folded portion 17C2 of the second trimming groove 17C and the folded portion 18C2 of the third trimming groove 18C is toward the first trimming groove 16C, and the grooves do not intersect with each other.

The first trimming groove 16C extends further in the longitudinal direction D1 than the second trimming groove 17C and the third trimming groove 18C. In other words, the distal end of the first trimming groove 16C in the extension direction (the apex of the folded portion) is located on the first longitudinal side of the distal end of the second trimming groove 17C and the third trimming groove 18C in the extension direction (the apex of the folded portion).

The longitudinal lengths of the second trimming groove 17C and the third trimming groove 18C are the same. In other words, the distal ends of both in the extension direction (the apex of the folded portion) are at the same position in the longitudinal direction D1.

The above configuration allows the potential difference between both sides of each trimming groove in the meandering formation portion 15C to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

In the above configuration, since each trimming groove has a folded portion, microcracks are unlikely to occur at the tip end of the trimming groove in the extension direction. In particular, since each folded portion has at least a part of a circular arc portion, current concentration at the corner portion at the tip of the folded portion can be mitigated, improving load characteristics.

More specifically, because the microcracks at the tip of the first trimming groove 16C are oriented in the same direction as the current path, the resistance value hardly changes even when the microcracks grow, i.e., the resistance value precision and reliability are improved. Furthermore, the resistance value fluctuations when the microcracks at the tips of the second trimming groove 17C and the third trimming groove 18C grow can be reduced, improving the resistance value precision and reliability.

Furthermore, the folded portion 17C2 of the second trimming groove 17C and the folded portion 18C2 of the third trimming groove 18 are folded back toward the first trimming groove 16C in the short direction D2, so that the locations where microcracks occur at the tips of the second trimming groove 17C and the third trimming groove 18C can be located in locations where almost no current flows. As a result, the resistance value precision and reliability are further improved.

In the fourth embodiment described above, all trimming grooves have turned-up portions, but in a modified example, only some of the trimming grooves may have turned-up portions. Specifically, it is preferable that the central groove has a turned-up portion, but the other trimming grooves do not have to have turned-up portions.

Fifth Embodiment
In the above-described first and second embodiments, the number of trimming grooves is three, but the number of trimming grooves may be any odd number, and is not limited to the first and second embodiments. In the fifth embodiment, an example in which the number of trimming grooves is five will be described.

The chip resistor 1D according to the fifth embodiment will be described with reference to FIG. 7. Note that the basic configuration of the chip resistor 1D is the same as that of the chip resistor 1 according to the first embodiment, so the differences will be mainly described.

The resistor 5D has a resistance value adjustment portion 12D, a first connection portion 31D, and a second connection portion 32D.

The resistance value adjustment section 12D is disposed at the longitudinal center of the surface 21D of the insulating substrate 2D, that is, between the first upper surface electrode 3D and the second upper surface electrode 4D. The resistance value adjustment section 12D is a portion where the resistance value of the resistor 5D is adjusted by laser trimming, as described below. The edge on the first side in the short side direction of the resistance value adjustment section 12D is the first edge 13D, and the edge on the second side in the short side direction is the second edge 14D (an example of a groove starting edge).

The first connection portion 31D and the second connection portion 32D are arranged in the longitudinal direction D1 (an example of a first direction). The first connection portion 31D includes a first rectangular portion 6D, a second rectangular portion 7D, and a third rectangular portion 8D (an example of a connection portion). The first rectangular portion 6D is connected to the first short-side side portion of the first upper surface electrode 3D and extends to the first long-side side. The second rectangular portion 7D extends from the tip of the first rectangular portion 6D to the second short-side side. The third rectangular portion 8D extends from the tip of the second rectangular portion 7D to the first long-side side and is connected to the end portion of the resistance value adjustment portion 12D on the second short-side side (the end portion on the second edge 14D side). The third rectangular portion 8D has an edge 49D (an example of an edge) on the first short-side side.

The second connection portion 32D includes a fourth rectangular portion 9D, a fifth rectangular portion 10D, and a sixth rectangular portion 11D (an example of a connection portion). The fourth rectangular portion 9D is connected to the first short-side portion of the second upper surface electrode 4D and extends to the second long-side. The fifth rectangular portion 10D extends from the tip of the fourth rectangular portion 9D to the second short-side side. The sixth rectangular portion 11D extends from the tip of the fifth rectangular portion 10D to the second long-side side and is connected to the end portion of the resistance value adjustment portion 12D on the second short-side side (the end portion on the second edge 14D side). In the above-mentioned configuration, the sixth rectangular portion 11D is provided in the vicinity of the second edge 14D of the resistance value adjustment portion 12D. The sixth rectangular portion 11D has an edge 50D (an example of an edge) on the first short-side side. The short-side position of edge 49D of third rectangular portion 8D and edge 50D of sixth rectangular portion 11D is set as voltage reference position 51D.

The resistance value adjustment section 12D is formed with a meandering forming section 15D. The meandering forming section 15D has a trimming groove for forming the resistance value adjustment section 12D into a meandering shape. Specifically, the meandering forming section 15D has a first trimming groove 16D (an example of a central groove), a second trimming groove 17D (an example of a side groove), a third trimming groove 18D (an example of a side groove), a fourth trimming groove 19D, and a fifth trimming groove 20D. The first trimming groove 16D, the second trimming groove 17D, the third trimming groove 18D, the fourth trimming groove 19D, and the fifth trimming groove 20D extend parallel to the short direction D2 (an example of a second direction) from the second edge 14D of the resistance value adjustment section 12B and are linear. The second trimming groove 17D is disposed on the second longitudinal side of the first trimming groove 16D. The third trimming groove 18D is disposed on the first longitudinal side of the first trimming groove 16D. The fourth trimming groove 19D is disposed on the second longitudinal side of the second trimming groove 17D. The fifth trimming groove 20D is disposed on the first longitudinal side of the third trimming groove 18D.

The first trimming groove 16D extends further in the short direction D2 than the second trimming groove 17 and the third trimming groove 18. In other words, the distal end portion (tip surface) of the first trimming groove 16D in the extension direction is located on the first side in the short direction than the distal end portions (tip surfaces) of the second trimming groove 17D and the third trimming groove 18D in the extension direction.

The second trimming groove 17D and the third trimming groove 18D extend further in the short direction D2 than the fourth trimming groove 19D and the fifth trimming groove 20D. The short-side lengths of the second trimming groove 17D and the third trimming groove 18D are the same. In other words, the distal ends (tip surfaces) of both of them in the extension direction are at the same position in the short-side direction D2.

The short-side lengths of the fourth trimming groove 19D and the fifth trimming groove 20D are the same, that is, the distal ends (tip surfaces) of both of them in the extension direction are at the same position in the short-side direction D2.

To explain the above configuration in another way, the second trimming groove 17D and the third trimming groove 18D are shorter than the first trimming groove 16D, and the fourth trimming groove 19D and the fifth trimming groove 20D are shorter than the second trimming groove 17D and the third trimming groove 18D. This realizes a configuration in which the trimming grooves other than the trimming groove in the center in the first direction out of the three or more odd number of trimming grooves are shorter than the adjacent trimming groove in the center in the first direction.

The above configuration allows the potential difference between both sides of each trimming groove in the meandering forming portion 15D to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

If the short-side length from the voltage reference position 51D to the tip of the first trimming groove 16D is a1, and the short-side length from the voltage reference position 51D to the tips of the second trimming groove 17D and the third trimming groove 18D is b1, then b1/a1 ≧ 0.42 and b1/a1 < 1.00 are satisfied. In this case, the potential difference on both sides of each trimming groove can be reduced compared to the conventional example of two trimming grooves, so voltage breakdown in the groove portion is less likely to occur, and characteristic abnormalities can be suppressed.

In this embodiment, it is preferable that b1 = (4 x a1)/5 holds. This condition can be obtained from the formula b1 = (2n x a1)/(2n+1). In the above formula, the number of trimming grooves is 2n+1 (n is a positive integer). When the above formula holds, the potential difference between both sides of each groove can be reduced to approximately 1/(2n+1) compared to the conventional case of a single groove.

Furthermore, if the short-side length from the voltage reference position 51D to the ends of the fourth trimming groove 19D and the fifth trimming groove 20D is b2, it is preferable that b2 = (2 x a1) / 5 be satisfied. This condition is obtained from the formula b2 = {2 x (n-1) x a1} / (2n + 1).

Sixth Embodiment
A chip resistor 1E according to the sixth embodiment will be described with reference to FIG. 8. The basic configuration of the chip resistor 1E is the same as that of the chip resistor 1E according to the fifth embodiment, so the differences will be mainly described. In this embodiment, each trimming groove has a folded portion, so that the same effect as that described in the second embodiment can be obtained. However, in this embodiment, the description of the configuration and effect of the folded portion will be omitted.

The resistance value adjustment section 12E has a meandering formation section 15E. The meandering formation section 15E has a trimming groove for forming the resistance value adjustment section 12E into a meandering shape. Specifically, the meandering formation section 15E has a first trimming groove 16E (an example of a central groove), a second trimming groove 17E (an example of a side groove), a third trimming groove 18E (an example of a side groove), a fourth trimming groove 19E, and a fifth trimming groove 20E. The first trimming groove 16E, the second trimming groove 17E, the third trimming groove 18E, the fourth trimming groove 19E, and the fifth trimming groove 20E extend parallel to the short direction D2 (second direction) from the second edge 14E (an example of a groove starting edge) of the resistance value adjustment section 12E, and are linear. The second trimming groove 17E is disposed on the second longitudinal side of the first trimming groove 16E. The third trimming groove 18E is disposed on the first longitudinal side of the first trimming groove 16E. The fourth trimming groove 19E is disposed on the second longitudinal side of the second trimming groove 17E. The fifth trimming groove 20E is disposed on the first longitudinal side of the third trimming groove 18E.

The first trimming groove 16E extends further in the short direction D2 than the second trimming groove 17E and the third trimming groove 18E. In other words, the distal end of the first trimming groove 16E in the extension direction (the apex of the folded portion) is located on the first side in the short direction than the distal end of the second trimming groove 17E and the third trimming groove 18E in the extension direction (the apex of the folded portion).

The second trimming groove 17E and the third trimming groove 18E extend further in the short direction D2 than the fourth trimming groove 19E and the fifth trimming groove 20E. The short-side lengths of the second trimming groove 17E and the third trimming groove 18E are the same, that is, the most distal portions of both in the extension direction (the apex of the folded portion) are at the same position in the short-side direction D2.

The short-side lengths of the fourth trimming groove 19E and the fifth trimming groove 20E are the same, that is, the most distal portions of both in the extension direction (the apex of the folded portion) are at the same position in the short-side direction D2.

The above configuration allows the potential difference between both sides of each trimming groove in the meandering forming portion 15E to be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

(Modification)
The above-described embodiments are merely one of various embodiments of the present disclosure. The above-described embodiments can be modified in various ways depending on the design and the like as long as the object of the present disclosure can be achieved. Below, modified examples of the above-described embodiments are listed. The modified examples described below can be applied in appropriate combination.

The number of trimming grooves may be an odd number greater than or equal to seven.

The lengths of the second and third trimming grooves may differ, for example by ±5%.

The lengths of the fourth and fifth trimming grooves may differ, for example by ±5%.

The chip resistor 1 may be a thin film chip resistor.

The folded portion of the trimming groove is not limited to a combination of a semicircular arc-shaped folded portion and a straight tip portion. However, it is preferable that the folded portion be smooth, i.e., without corners.

The folded portion of the trimming groove does not have to extend toward the groove starting edge. For example, the folded portion may extend in a direction that intersects with the straight portion.

(Aspects)
The present specification discloses the following aspects.

The chip resistor (1, 1A, 1B, 1C, 1D, 1E) according to the first aspect comprises a substrate (2, 2A, 2B, 2C, 2D), a pair of electrodes (3, 3B, 3D, 4, 4B, 4D), and a resistor (5, 5A, 5B, 5C, 5D). The pair of electrodes (3, 3B, 3D, 4, 4B, 4D) are provided at both ends of one surface (21, 21B, 21D) of the substrate (2, 2A, 2B, 2C, 2D). The resistor (5, 5A, 5B, 5C, 5D) is provided between the pair of electrodes (3, 3B, 3D, 4, 4B, 4D) on one surface (21) of the substrate (2, 2A, 2B, 2C, 2D). The resistor (5, 5A, 5B, 5C, 5D) has a pair of connection parts (31, 31D, 32, 32D) respectively connected to a pair of electrodes (3, 3B, 3D, 4, 4B, 4D) and a resistance value adjustment part (12, 12A, 12B, 12C, 12D, 12E) provided between the pair of connection parts (31, 31D, 32, 32D). The resistance value adjustment part (12, 12A, 12B, 12C, 12D, 12E) has a meandering forming part (15, 15A, 15B, 15C, 15D, 15E) formed therein for forming the resistance value adjustment part (12, 12A, 12B, 12C, 12D, 12E) into a meandering shape. The meandering forming portion (15, 15A, 15B, 15C, 15D, 15E) has three or more odd number of trimming grooves (16, 16A, 16B, 16C, 16D, 16E, 17, 17A, 17B, 17C, 17D, 17E, 18, 18A, 18B, 18C, 18D, 18E). Each of the three or more odd-numbered trimming grooves (16, 16A, 16B, 16C, 16D, 16E, 17, 17A, 17B, 17C, 17D, 17E, 18, 18A, 18B, 18C, 18D, 18E) has a straight portion extending from the groove starting edge (14, 14A, 14B, 14C, 14D, 14E) of the resistance value adjustment portion (12, 12A, 12B, 12C, 12D, 12E) along a second direction perpendicular to the first direction in which the pair of connection portions (31, 31D, 32, 32D) are aligned. Of the three or more odd number of trimming grooves (16, 16A, 16B, 16C, 16D, 16E, 17, 17A, 17B, 17C, 17D, 17E, 18, 18A, 18B, 18C, 18D, 18E), the trimming grooves other than the one located in the center in the first direction are shorter than the adjacent trimming groove located toward the center in the first direction.

According to this aspect, the potential difference between both sides of each trimming groove in the meandering formation section can be reduced to less than half that of a single trimming groove. Therefore, a meandering pattern that can withstand a high potential difference can be formed.

In the chip resistor according to the second aspect, in the first aspect, at least one of the pair of connection parts (31, 31D, 32, 32D) has a connection part connected to the end of the resistance value adjustment part (12) on the groove starting edge side. If the second direction length from the edge (49, 50) of the connection part (6, 11) opposite the groove starting edge (14, 14A, 14B, 14C, 14D, 14E) to the tip of the central groove (16) of the three or more odd number of trimming grooves (16, 17, 18) is a1, and the second direction length from the edge (49, 50) of the connection part (6, 11) to the tips of the side grooves (17, 18) on both sides of the central groove (16) is b1, then 0.4≦b1/a1<1.00 is satisfied.

According to this embodiment, the potential difference between both sides of each trimming groove can be reduced compared to the conventional example with two trimming grooves, making it less likely that voltage breakdown will occur in the groove portion, and therefore suppressing characteristic abnormalities.

In the chip resistor according to the third aspect, in the first or second aspect, when the number of trimming grooves (16, 17, 18) is 2n+1 (n is a positive integer), b1 = (2n x a1)/(2n+1) holds for the side grooves (17, 18).

According to this embodiment, the potential difference on both sides of each trimming groove can be reduced compared to the conventional example of two trimming grooves, making it less likely that voltage breakdown will occur in the groove portion, and therefore suppressing characteristic abnormalities.

In the chip resistor (1D) according to the fourth aspect, in any of the first to third aspects, when the number of trimming grooves is five, if the second direction length from the edge (49D, 50D) of the connection portion (8D, 11D) to the tip of the groove (19D, 20D) on the opposite side of the central groove (16D) of the side grooves (16D, 17D) is b2, then b2 = {2 x (n-1) x a1}/(2n+1) holds.

According to this embodiment, the potential difference on both sides of each trimming groove can be reduced compared to the conventional example of two trimming grooves, making it less likely that voltage breakdown will occur in the groove portion, and therefore suppressing characteristic abnormalities.

In the chip resistor (1A, 1C, 1E) according to the fifth aspect, in any of the first to fourth aspects, the central groove (16A, 16C, 16E) further has a folded portion (16A2, 16C2) that extends from the tip of the straight portion (16A1, 16C1) and is bent in the folded direction.

According to this embodiment, since the central groove has a folded portion, microcracks are less likely to occur at the most distal part of the central groove in the extension direction.

In the chip resistor (1A, 1C, 1E) according to the sixth aspect, in the fifth aspect, all trimming grooves (16A, 17A, 18A, 16C, 17C, 18C, 16E, 17E, 18E, 19E, 20E) have folded portions (17A2, 18A2, 17C2, 18C2) that extend from the tip of the straight portion (17A1, 18A1, 17C1, 18C1) in a folded direction.

According to this aspect, since all trimming grooves have a folded portion, microcracks are unlikely to occur at the most distal part of each trimming groove in the extension direction.

In the chip resistor (1A, 1C, 1E) according to the seventh aspect, in the sixth aspect, the folded portions (17A2, 18A2, 17C2, 18C2) of the trimming grooves (17A, 18A, 17C, 18C, 17E, 18E, 19E, 20E) other than the central groove (16A, 16C, 17C) are bent toward the central groove (16A, 16C, 16E).

According to this embodiment, the location where microcracks occur at the tip of the trimming groove other than the central groove can be located in a location where almost no current flows. As a result, the resistance value precision and reliability are further improved.

In the chip resistor (1A, 1C, 1E) according to the eighth aspect, in the seventh aspect, the folded portion (16A2, 17A2, 18A2, 17C2, 18C2) of the trimming groove has at least a part of an arcuate portion.

According to this embodiment, since the folded portion has an arcuate portion in part, microcracks are less likely to occur at the tip end of the trimming groove in the extension direction.

1, 1A, 1B, 1C, 1D, 1E: Chip resistor 2, 2A, 2B, 2C, 2D: Insulating substrate (substrate)
3, 3B, 3D: First upper electrode (electrode)
4, 4B, 4D: Second upper surface electrode (electrode)
5, 5A, 5B, 5C, 5D: resistors 12, 12A, 12B, 12C, 12D, 12E: resistance value adjustment parts 14, 14A, 14B, 14C, 14D, 14E: second edges (groove starting edges)
15, 15A, 15B, 15C, 15D, 15E: meandering forming portion 16, 16A, 16B, 16C, 16D, 16E: first trimming groove (central groove)
17, 17A, 17B, 17C, 17D, 17E: second trimming groove 18, 18A, 18B, 18C, 18D, 18E: third trimming groove 16A1, 16C1, 17A1, 17C1, 18A1, 18C1: straight portion 16A2, 16C2, 17A2, 17C2, 18A2, 18C2: folded portion 21, 21B, 21D: surface 31, 31D: first connection portion 32, 32D: second connection portion

Claims (8)

A substrate;
A pair of electrodes provided on both ends of one surface of the substrate;
a resistor provided between the pair of electrodes on the one surface of the substrate,
The resistor is
A pair of connection parts respectively connected to the pair of electrodes;
a resistance value adjusting portion provided between the pair of connection portions,
a meandering forming portion for forming the resistance value adjustment portion into a meandering shape is formed in the resistance value adjustment portion,
The meandering forming portion has an odd number of trimming grooves, which is three or more;
each of the three or more odd number of trimming grooves has a straight line portion extending from a groove starting edge of the resistance value adjustment portion along a second direction perpendicular to a first direction in which the pair of connection portions are aligned,
Among the three or more odd number of trimming grooves, a trimming groove other than the trimming groove located at the center in the first direction is shorter than an adjacent trimming groove located at the center in the first direction.
Chip resistors. At least one of the pair of connection parts has a connection part connected to an end part of the resistance value adjustment part on the groove starting edge side,
When a1 is a second direction length from an edge of the connecting portion opposite to the groove start edge to a tip of a central groove among the three or more odd number of trimming grooves, and b1 is a second direction length from the edge of the connecting portion to tips of both side grooves on both sides of the central groove, 0.42≦b1/a1<1.00 is satisfied.
The chip resistor according to claim 1 . When the number of the trimming grooves is 2n+1 (n is a positive integer), the relationship b1=(2n×a1)/(2n+1) is satisfied for the side grooves.
The chip resistor according to claim 2 . When the number of the trimming grooves is five, if the length in the second direction from the edge of the connection portion to the tip of the groove on the opposite side to the central groove of the side grooves is b2, then b2 = {2 × (n-1) × a1} / (2n + 1) is satisfied.
The chip resistor according to claim 3 . The central groove further has a folded portion that is bent and extends from a tip of the straight portion in a folded direction.
The chip resistor according to any one of claims 2 to 4. All of the trimming grooves have a folded portion that extends from a tip of the straight portion in a folded direction.
The chip resistor according to claim 5 . The folded portion of the trimming groove other than the central groove is bent toward the central groove.
The chip resistor according to claim 6 . The folded portion of the trimming groove has at least a part of an arcuate portion.
The chip resistor according to claim 7.

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