Chip resistor

Abstract

The invention provides a chip resistor which has excellent surge characteristics and is suitable for miniaturization. In this chip resistor (1), a resistor body (7) that connects a first surface electrode (3) and a second surface electrode (4) is printed into a crank shape having a first resistor body part (7a), a second resistor body part (7b), and a third resistor body part (7c). A first region (S1) of the resistor (7), which is surrounded by a parallelogram having a first lead-out portion (7b-1) of the second resistor portion (7b) and a second lead-out portion (7c-1) of the third resistor portion (7c) on opposite sides, is a region where a large amount of current flows, and two second regions (S2a, S2b) located outside the first region (S1) are regions where a small amount of current is distributed. An adjustment groove (12) for adjusting a resistance value is integrally formed in an L-shaped cut shape, and has: a rough adjustment section (12a) that passes through a second region (S2a) in contact with the lower edge of a first resistor body section (7a) and extends into a first region (S1); and a fine adjustment section (12b) that passes through the inside of the first region (S1) from the tip of the coarse adjustment section (12a) and extends to a position at which the fine adjustment section (12b) reaches the second region (S2a) again.

Description

Technical Field

[0001] The present invention relates to a chip resistor whose resistance value is adjusted by forming an adjustment groove in a resistor body. Background Art

[0002] The chip resistor is mainly composed of the following components: an insulating substrate of a rectangular shape, a pair of surface electrodes arranged opposite to each other at a specified interval on the surface of the insulating substrate, a pair of back electrodes arranged opposite to each other at a specified interval on the back side of the insulating substrate, end electrodes bridging the surface electrodes and the back electrodes, a resistor body bridging the paired surface electrodes, and a protective film covering the resistor body.

[0003] Usually, when manufacturing such chip resistors, after forming a large number of electrodes, resistors, protective films, etc. on a large-sized sheet substrate, the large-sized substrate is divided along a grid-shaped dividing line (such as a dividing groove) to obtain a plurality of chip resistors. In the manufacturing process of such chip resistors, a plurality of resistors are formed on a single side of a large-sized substrate by printing and sintering resistor paste, but due to the influence of position deviation during printing, seepage, or uneven temperature in the sintering furnace, it is difficult to avoid slight deviations in the size and film thickness of each resistor, so the so-called resistance value adjustment operation is performed, that is, an adjustment groove is formed on each resistor in the state of the large-sized substrate to set it to the desired resistance value.

[0004] When a surge voltage caused by static electricity, power supply noise, etc. is applied to a chip resistor of this structure, the characteristics of the resistor may be affected by excessive electrical stress, and in the worst case, the resistor may be damaged. In order to improve the surge characteristics, it is known that if the resistor body is set to a meandering shape (zigzag shape) to increase the total length, the potential drop can be smoothed, which can improve the surge characteristics.

[0005] For example, as described in Patent Document 1, a chip resistor is proposed, in which a resistor body having a meandering shape is formed on the main surface of an insulating substrate by printing technology, and then adjustment grooves extending in straight lines from two opposite sides of the resistor body are formed in reverse order, and the two adjustment grooves are extended to a position where the top ends of the two adjustment grooves intersect with each other, thereby making the resistor body meander near the top ends of the two adjustment grooves, thereby increasing the total length.

[0006] In a chip resistor constructed in this way, two adjustment grooves extending in a straight line at 180 degrees in opposite directions are formed on the resistor body, so that the main current path of the resistor body changes by 180 degrees at the location where the top ends of the two adjustment grooves intersect each other. As a result, the total length of the printed resistor body becomes longer, and the surge characteristics can be improved.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2006-19694.

[0010] Problem that the invention aims to solve

[0011] However, in the prior art described in Patent Document 1, in a configuration where the tops of two adjustment grooves intersect each other and the current path is turned 180 degrees, microcracks generated at the tops of the two adjustment grooves appear at the turning portion where the load is concentrated, so when a high voltage is applied, the resistor may be damaged due to a local temperature rise. In particular, the following problem occurs: in a small-sized chip resistor with a small substrate area, as the total length of the resistor is lengthened by the adjustment groove, the width dimension of the resistor becomes very narrow. Therefore, when the chip resistor is provided in an environment with a large power load, the current per unit area (current density) becomes large, and the resistor cannot withstand the load and becomes easily damaged. Summary of the invention

[0012] The present invention has been made in view of the actual situation of the prior art, and therefore an object of the present invention is to provide a chip resistor which is excellent in surge characteristics and is also suitable for miniaturization.

[0013] Solutions for solving problems

[0014] In order to achieve the above-mentioned purpose, the chip resistor of the present invention is characterized in that it has: an insulating substrate of a rectangular shape; a first surface electrode and a second surface electrode arranged opposite to each other at both ends of the insulating substrate with a gap of a fixed width therebetween; and a resistor body, which is arranged in the gap to bridge the first surface electrode and the second surface electrode, and the chip resistor adjusts the resistance value by forming an adjustment groove in the resistor body, and the resistor body has: a first resistor body part of a rectangular shape, which extends parallel to the first surface electrode and the second surface electrode; a second resistor body part of a rectangular shape, which is connected to a side of the first resistor body part through a first lead-out part connected to the first surface electrode; and a third resistor body. A resistor body portion, which is connected to the other side portion of the first resistor body portion through a second lead-out portion connected to the second surface electrode. When an area within the resistor body surrounded by a parallelogram with the first lead-out portion and the second lead-out portion as opposite sides is set as a first area, and two triangular areas located outside the first area are respectively set as second areas, the adjustment groove has: a coarse adjustment portion, which extends in a straight line from one of the opposing outer edges of the first resistor body portion as a starting end portion toward the other outer edge edge, and at least reaches the first area through the second area; and a fine adjustment portion, which extends from the top end of the coarse adjustment portion in a direction orthogonal to the coarse adjustment portion, at least passes through the first area and extends to reach the second area again.

[0015] In the chip resistor constructed in this way, since the resistor body having the first resistor body part, the second resistor body part and the third resistor body part is formed in a crank shape as a whole, the total length of the resistor body can be ensured and stable surge characteristics can be obtained. In addition, in the resistor body of such a shape, the first area becomes a part where more current flows, and the second area becomes a part where less current is distributed. The adjustment groove for adjusting the resistance value is formed in an L-shaped cutting shape in a manner of passing from the second area through the first area and then reaching the second area again, so that the part where microcracks are generated can be kept away from the current path where the load is concentrated. Moreover, after the resistance value is adjusted, the main current path becomes longer in a manner without a turning part, so that the surge characteristics can be further improved on the basis of reducing the adverse effects on the characteristics caused by microcracks.

[0016] In the chip resistor of the above structure, when the top of the rough adjustment portion as the bending portion of the adjustment groove is located in the first region, the width dimension of the first resistor body portion narrowed by the amount of cutting of the rough adjustment portion is limited to a certain extent, so the resistance width of the resistor body will not be extremely thin, and even if the chip resistor is miniaturized, it can cope with high power. Among them, the rough adjustment portion of the adjustment groove can pass through the first region and extend to the position of the second region. In this case, after the rough adjustment portion is formed from one second region through the first region to another second region, the fine adjustment portion can be extended from the top of the rough adjustment portion from another second region through the first region to one second region.

[0017] In addition, in the chip resistor of the above structure, when the length of the outer edge of the first resistor body portion is set to L, if the starting end of the adjustment groove is set within the range of L / 2 from the first lead-out portion of the second resistor body portion or the second lead-out portion of the third resistor body portion, the current path after the resistance value is adjusted can be extended longer, and therefore it is preferred.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide a chip resistor which is excellent in surge characteristics and suitable for miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a top view of the chip resistor according to the first embodiment of the present invention.

[0021] Figure 2 is along Figure 1 Cross-sectional view along line II-II.

[0022] Figure 3 yes Figure 1 An illustration of the resistor element of a chip resistor.

[0023] Figure 4 It is a top view of a chip resistor according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] Figure 1 is a top view of a chip resistor according to a first embodiment of the present invention, Figure 2 is along Figure 1 Cross-sectional view along line II-II.

[0026] like Figure 1 and Figure 2As shown, the chip resistor 1 of the first embodiment example is mainly composed of the following components: an insulating substrate 2 of a rectangular shape; a first surface electrode 3 and a second surface electrode 4 provided at both ends of the surface of the insulating substrate 2 in the short side direction; a first back electrode 5 and a second back electrode 6 provided at both ends of the back side of the insulating substrate 2 in the short side direction; a resistor 7 that conducts between the paired first surface electrode 3 and the second surface electrode 4; a primer 8 provided to cover the resistor 7; an outer coating 9 provided to cover the primer 8; a pair of end surface electrodes 10 provided at both end surfaces in the short side direction of the insulating substrate 2; and a pair of external electrodes 11 provided to cover the end surface electrodes 10. In addition, in the following description, the long side direction ( Figure 1 The left-right direction of the insulating substrate 2 is set as the X-axis, and the short side direction of the insulating substrate 2 ( Figure 1 The up and down directions) are set as the Y axis.

[0027] The insulating substrate 2 is a plurality of substrates obtained by dividing a sheet-like large-sized substrate along primary dividing grooves and secondary dividing grooves extending horizontally and vertically. The main component of the large-sized substrate is a ceramic substrate containing alumina as a main component.

[0028] The first surface electrode 3 and the second surface electrode 4 are formed by screen printing an Ag-based paste with Ag (silver) as the main component and drying and sintering. These first surface electrodes 3 and second surface electrodes 4 are formed along the long side of the surface of the insulating substrate 2 and separated by a gap of a fixed width in the short side direction (Y-axis direction).

[0029] The first back electrode 5 and the second back electrode 6 are formed by screen printing Ag-based paste and drying and sintering. These first back electrode 5 and the second back electrode 6 are formed along the long side of the back side of the insulating substrate 2 and separated by a fixed width gap in the short side direction.

[0030] The resistor 7 is formed by screen printing a resistor paste such as ruthenium oxide, and then drying and sintering it. The details will be described later. The resistor 7 is formed with an adjustment groove 12, through which the initial resistance value of the printed resistor 7 can be adjusted to a target resistance value.

[0031] The undercoat layer 8 is formed by screen-printing a glass paste, drying it, and baking it. The undercoat layer 8 is formed so as to cover the entire resistor 7 before the adjustment groove 12 is formed.

[0032] The overcoat layer 9 is formed by screen-printing a resin paste such as an epoxy resin or a phenolic resin and then curing it by heating. The overcoat layer 9 is formed so as to cover the entire undercoat layer 8 after the adjustment groove 12 is formed.

[0033] The pair of end surface electrodes 10 are formed by sputtering Ni—Cr or the like, and respectively provide electrical conduction between the first front electrode 3 and the first back electrode 5 , and between the second front electrode 4 and the second back electrode 6 , which are separated by the end surface of the insulating substrate 2 .

[0034] The pair of external electrodes 11 has a double-layer structure of an inner separator 13 and an outer external connection layer 14 , wherein the separator 13 is a Ni plating layer formed by electroplating and the external connection layer 14 is a Sn plating layer formed by electroplating.

[0035] Figure 3 FIG. 1 is an explanatory diagram of the resistor 7 included in the chip resistor 1. Figure 3 (A) shows the state before the adjustment groove 12 is formed, Figure 3 (B) shows a state after the adjustment groove 12 is formed.

[0036] like Figure 3 As shown in (A), the first surface electrode 3 and the second surface electrode 4 are arranged opposite to each other at both ends of the short side direction of the surface of the insulating substrate 2 with a gap D of a fixed width therebetween, and a resistor 7 is printed in the gap D in such a way that the first surface electrode 3 and the second surface electrode 4 are electrically connected. The resistor 7 has: a rectangular first resistor body portion 7a, which is arranged in the central portion of the gap D and extends parallel to the first surface electrode 3 and the second surface electrode 4 (in the X-axis direction); a rectangular second resistor body portion 7b, which extends from a first lead-out portion 7b-1 connected to the first surface electrode 3 in the Y-axis direction to the middle of the gap D and is connected to the side portion of the first resistor body portion 7a on the left side of the figure; and a third resistor body portion 7c, which extends from a second lead-out portion 7c-1 connected to the second surface electrode 4 in the Y-axis direction to the middle of the gap D and is connected to the side portion of the first resistor body portion 7a on the right side of the figure.

[0037] The resistor 7 printed in this manner becomes a crank shape (crank shape) that is point-symmetrical with respect to the center of the first resistor body portion 7a. The total length of the resistor 7 is lengthened by the crank shape, so the total length of the resistor 7 is ensured and the surge characteristics are stable. Moreover, in the resistor 7 of such a shape, the main current path where the most current flows from the first surface electrode 3 to the second surface electrode 4 is a straight path from the first lead-out portion 7b-1 connected to the first surface electrode 3 through the center of the first resistor body portion 7a and toward the second lead-out portion 7c-1 connected to the second surface electrode 4. That is, if the area surrounded by the parallelogram with the first lead-out portion 7b-1 and the second lead-out portion 7c-1 as opposite sides in the resistor 7 is set as the first area S1, and the two triangular areas sandwiching the first area S1 and located outside are set as the second areas S2a and S2b, respectively, then the first area S1 is a part where a lot of current flows, and the two second areas S2a and S2b are parts where less current is distributed.

[0038] like Figure 3 As shown in (B), by forming one adjustment groove 12 in such a crank-shaped resistor 7, the initial resistance value of the resistor 7 after printing is adjusted to a target resistance value.

[0039] The adjustment groove 12 is formed in an L-shaped cut shape as a whole, and is composed of the following parts: a coarse adjustment portion 12a, which is located at the lower edge of the first resistor body portion 7a and extends in a straight line in the upper direction of the Y axis; and a fine adjustment portion 12b, which is bent at a right angle from the top of the coarse adjustment portion 12a and extends in a straight line in the right direction of the X axis. Here, the coarse adjustment portion 12a passes through the second area S2a connected to the lower edge of the first resistor body portion 7a and extends to the first area S1, and the fine adjustment portion 12b passes through the first area S1 from the top of the coarse adjustment portion 12a and extends to a position where it reaches the second area S2a again.

[0040] Furthermore, since the coarse adjustment portion 12a of the adjustment groove 12 is formed from the second region S2a where the current distribution in the resistor body 7 is small as the starting position to the position where it reaches the first region S1, the resistance value can be roughly adjusted by narrowing the width dimension of the first resistor body portion 7a by extending the cut-in amount of the coarse adjustment portion 12a in the Y-axis direction. On the other hand, the fine adjustment portion 12b of the adjustment groove 12 is formed from the first region S1 where the top of the coarse adjustment portion 12a is located toward the second region S2a where the current distribution is small, and the ratio of the resistance value increment of the fine adjustment portion 12b to the cut-in amount increment is small, the resistance value can be finely adjusted with high precision by extending the cut-in amount of the fine adjustment portion 12b in the X-axis direction. Furthermore, the top of the adjustment groove 12 formed in an L-shaped cut shape is located in the second region S2a, so the location where microcracks are generated can be kept away from the current path where the load is concentrated. At this time, by extending the tip of the adjustment groove 12 to the third resistor body portion 7 c , the microcrack occurrence site can be further away from the current path, thereby further reducing the influence of the microcracks.

[0041] Furthermore, in the resistor 7 after the resistance value is adjusted by the adjustment groove 12, the main current path through which the most current flows from the first surface electrode 3 toward the second surface electrode 4 is a bent path from the first lead-out portion 7b-1 connected to the first surface electrode 3 through the corner of the adjustment groove 12 (the top of the coarse adjustment portion 12a) toward the second lead-out portion 7c-1 connected to the second surface electrode 4. This bent main current path is longer than the straight main current path flowing through the resistor 7 before the resistance value is adjusted, so the surge characteristics ensured by printing the resistor 7 into a crank shape are further improved by forming the adjustment groove 12.

[0042] Here, although the starting position of the adjustment groove 12 in the second area S2a is not specifically limited, when the length of the outer edge of the first resistor body part 7a along the X-axis direction is set to L, the starting position of the adjustment groove 12 is set within the range of L / 2 from the first lead-out part 7b-1 of the second resistor body part 7b.

[0043] In addition, the adjustment groove 12 can be formed with the upper edge of the first resistor body 7a as the starting position instead of the lower edge. In this case, after the coarse adjustment portion 12a is formed to reach the first region S1 through the second region S2b connected to the upper edge of the first resistor body 7a, the fine adjustment portion 12b is formed to reach the second region S2b again from the top of the coarse adjustment portion 12a through the first region S1. At this time, the starting position of the second region S2b of the adjustment groove 12 is set within the range of L / 2 from the second lead-out portion 7c-1 of the third resistor body 7c.

[0044] As described above, in the chip resistor 1 of the first embodiment, the resistor body 7 printed in the gap D between the first surface electrode 3 and the second surface electrode 4 is printed as a whole in a crank shape, and has: a rectangular first resistor body portion 7a, which is arranged in the central portion of the gap D and extends parallel to the first surface electrode 3 and the second surface electrode 4; a rectangular second resistor body portion 7b, which extends from a first lead-out portion 7b-1 connected to the first surface electrode 3 in the Y-axis direction to the middle of the gap D and is connected to one side of the first resistor body portion 7a; and a third resistor body portion 7c, which extends from a second lead-out portion 7c-1 connected to the second surface electrode 4 in the Y-axis direction to the middle of the gap D and is connected to the other side of the first resistor body portion 7a, thereby ensuring the total length of the resistor body 7 and having a stable surge characteristic.

[0045] Moreover, in such a crank-shaped resistor 7, the first region S1 surrounded by a parallelogram with the first lead-out portion 7b-1 and the second lead-out portion 7c-1 as opposite sides is a portion where a large amount of current flows, and the two second regions S2a and S2b of a triangular shape sandwiching the first region S1 and located on the outside are portions where less current is distributed, and the adjustment groove 12 for adjusting the resistance value is formed in an L-shaped cut shape in a manner that passes through the first region S1 from any second region S2a (or S2b) and reaches the second region S2a (or S2b) again, so that the location where microcracks are generated can be kept away from the current path where the load is concentrated. Moreover, after the resistance value is adjusted, the main current path becomes longer in a manner without a turning portion, so that the surge characteristics can be further improved on the basis of reducing the adverse effects on the characteristics caused by microcracks.

[0046] In addition, since the top position of the rough adjustment portion 12a as the bent portion of the adjustment groove 12 is set in the first area S1, the width dimension of the first resistor body portion 7a, which becomes narrower as the rough adjustment portion 12a cuts in, is limited to a certain extent. As a result, the resistance width of the resistor body 7 will not become extremely thin, and even a miniaturized chip resistor 1 can cope with high power situations.

[0047] In addition, when the length of the outer edge of the first resistor body portion 7a along the X-axis direction is set to L, the starting end of the adjustment groove 12 is set within the range of L / 2 from the first lead-out portion 7b-1 of the second resistor body portion 7b or the second lead-out portion 7c-1 of the third resistor body portion 7c, so that the current path after the resistance value is adjusted can be extended.

[0048] Figure 4 is a top view of a chip resistor 20 according to a second embodiment of the present invention. Figures 1 to 3 The corresponding parts are marked with the same symbols, and repeated descriptions are omitted as appropriate.

[0049] In the chip resistor 20 of the second embodiment, the adjustment groove 12 for adjusting the resistance value formed in the resistor body 7 is composed of the following parts: a coarse adjustment portion 12a, which passes through the first area S1 from a second area S2a and extends in the upward direction of the Y axis to another second area S2b; and a fine adjustment portion 12b, which passes through the first area S1 from the top of the coarse adjustment portion 12a located in the second area S2b and extends again in the right direction of the X axis to a second area S2a. Other structures are basically the same as the chip resistor 1 of the first embodiment.

[0050] In the second embodiment, the adjustment groove 12 can also be formed with the upper edge of the first resistor body portion 7a as the starting position. In this case, after the coarse adjustment portion 12a is formed from another second region S2b through the first region S1 and to one second region S2a along the downward direction of the Y axis, the fine adjustment portion 12b is formed again from one second region S2a through the first region S1 and to another second region S2b along the left direction of the X axis.

[0051] In the chip resistor 20 of the second embodiment constructed in this way, the resistor body 7 is printed in a crank shape, so that the total length of the resistor body 7 can be ensured and stable surge characteristics can be obtained. In addition, the adjustment groove 12 for adjusting the resistance value is formed in an L-shaped cut shape, having: a coarse adjustment portion 12a, which passes through the first area S1 from any second area S2a (or S2b) and extends to another second area S2b (or S2a); and a fine adjustment portion 12b, which passes through the first area S1 from another second area S2b (or S2a) and extends again to a second area S2a (or S2b), so that the location where microcracks are generated can be kept away from the current path where the load is concentrated. In addition, after the resistance value is adjusted, the main current path becomes longer in a manner without a turning portion, so that the surge characteristics can be further improved on the basis of reducing the adverse effects on the characteristics caused by microcracks.

[0052] In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the main purpose of the present invention. All technical matters included in the technical ideas recorded in the scope of the claims are the objects of the present invention. The above-mentioned embodiments show preferred examples, but those skilled in the art can realize various alternative examples, modified examples, variant examples or improved examples according to the contents disclosed in this specification, which are also included in the technical scope recorded in the scope of the attached claims.

[0053] For example, although the first and second surface electrodes 3 and 4 and the first and second back electrodes 5 and 6 are formed along the long sides of the insulating substrate 2 in the above embodiments, they may be formed along the short sides of the insulating substrate 2 .

[0054] Description of Reference Numerals

[0055] 1.20: Chip resistor;

[0056] 2: Insulating substrate;

[0057] 3: first surface electrode;

[0058] 4: second surface electrode;

[0059] 5: first back electrode;

[0060] 6: second back electrode;

[0061] 7: resistor;

[0062] 7a: first resistor body;

[0063] 7b: second resistor body;

[0064] 7b-1: first lead-out portion;

[0065] 7c: third resistor body;

[0066] 7c-1: second lead-out portion;

[0067] 8: Base coating;

[0068] 9: outer coating;

[0069] 10: end surface electrode;

[0070] 11: external electrode;

[0071] 12: Adjustment slot;

[0072] 12a: coarse adjustment part;

[0073] 12b: Fine-tuning department;

[0074] 13: Isolation layer;

[0075] 14: External connection layer;

[0076] D: gap;

[0077] S1: first area;

[0078] S2a, S2b: The second area.

Claims

1. A chip resistor, characterized in that: have: An insulating substrate in the shape of a rectangular parallelepiped; A first surface electrode and a second surface electrode are disposed opposite to each other at both ends of the insulating substrate with a gap of a fixed width therebetween; as well as a resistor disposed in the gap to bridge the first surface electrode and the second surface electrode, The chip resistor adjusts the resistance value by forming an adjustment groove in the resistor body. The resistor has: a first resistor body portion having a rectangular shape, extending parallel to the first surface electrode and the second surface electrode; A second resistor body portion having a rectangular shape, which is connected to one side portion of the first resistor body portion via a first lead-out portion connected to the first surface electrode; as well as a third resistor body portion connected to the other side portion of the first resistor body portion via a second lead-out portion connected to the second surface electrode, When the area in the resistor body surrounded by a parallelogram with the first lead-out portion and the second lead-out portion as opposite sides is set as the first area, and two triangular areas located outside the first area are respectively set as the second area, The adjustment slot has: a coarse adjustment portion, which extends linearly from one of the opposing outer edges of the first resistor body portion as a starting end portion toward the other outer edge, and passes through the second region to at least reach the first region; and a fine adjustment portion extending from the top end of the coarse adjustment portion in a direction perpendicular to the coarse adjustment portion, passing through at least the first region and extending to reach the second region again.

2. The chip resistor according to claim 1, characterized in that: The top end of the coarse adjustment portion is located in the first area.

3. The chip resistor according to claim 1, characterized in that: When the length of the outer edge of the first resistor body is defined as L, the starting end portion of the adjustment groove is set within a range of L / 2 from the first lead-out portion or the second lead-out portion.

4. The chip resistor according to claim 1, characterized in that: The top end of the fine adjustment portion is located in the third resistor body portion.

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