CHIP RESISTOR AND METHOD FOR MANUFACTURING A CHIP RESISTOR

Abstract

Chip resistor (1, 20) having: an insulating substrate (2); a pair of electrodes (3, 4) arranged on the insulating substrate (2) so as to face each other at a predetermined distance; and a resistor (5) for bridging between the pair of electrodes (3, 4), wherein the resistor (5) is provided with trimming grooves (9, 10) to set a resistance value, wherein the resistor (5) comprises a printing body continuously connecting the pair of electrodes (3, 4), the printing body comprising connecting portions each connected to the pair of electrodes (3, 4) and a rectangular adjustment portion (8), the adjustment portion (8) being located between the connecting portions, wherein at least one of the connecting regions is a meandering region (6, 7) which changes its direction, wherein a first trimming groove (9) for coarse adjustment is formed in the adjustment region to extend a current path of the resistor (5), and a second trimming groove (10) for fine adjustment is formed in the meandering region (6, 7), wherein, when a direction between the pair of electrodes (3, 4) is referred to as the X direction and a direction perpendicular to the X direction is referred to as the Y direction, the meandering region (6, 7) has an extension region (6a, 7a) extending in the Y direction, an outer direction-changing region (6b, 7b) extending in the X direction for establishing a connection between one end of the extension region (6a, 7a) and one of the pair of electrodes (3, 4), and an inner direction-changing region (6c, 7c) extending in the X direction for establishing a connection between the other end of the extension region (6a, 7a) and the adjustment region (8), wherein the second trim groove (10) extends from one of the outer direction change region (6b, 7b) and the inner direction change region (6c, 7c) as the initial end position in the Y direction, and wherein a distal end of the second trim groove (10) does not reach an imaginary line (E) connecting the outer direction change region (6b, 7b) and the inner direction change region (6c, 7c) at the shortest distance.

Description

TECHNICAL FIELDThe present invention relates to a chip resistor in which trimming grooves are formed on a resistor provided on an insulating substrate to adjust a resistance value, and a method of manufacturing the same.PRIOR ARTA chip resistor is formed to mainly include a rectangular insulating substrate, a pair of front electrodes disposed on a front surface of the insulating substrate so as to oppose each other with a predetermined interval, a pair of rear electrodes disposed on a rear surface of the insulating substrate so as to oppose each other with a predetermined interval, end electrodes for bridging the front electrodes and the corresponding rear electrodes, a resistor for bridging the front electrode pair, and a protective film for covering the resistor.In a case of manufacturing this type of chip resistor, after electrodes, resistors, protective films, etc. present in plural pieces are collectively formed on a large-sized substrate, the large-sized substrate is generally divided along lattice-like division lines (e.g., division grooves) to obtain chip resistors present in plural pieces. The process for producing this type of chip resistor includes the step of printing and sintering resistor paste on one of the surfaces of the large-sized substrate to obtain chip resistors in plural pieces, thereby making it difficult to avoid occurrence of slight variations in the size and film thickness of each resistor due to positional deviation as well as bleeding during printing or influence of uneven temperatures in a sintering furnace, for example. Accordingly, in the above process, a resistance value setting operation is performed in which trimming grooves are formed on each resistor in a state where they are on the large-sized substrate to set a resistance value to a desired resistance value.When a surge voltage generated by static electricity, power supply noise or the like is applied to the chip resistor having the above-described configuration, the characteristic of the resistor is deteriorated by excessive electric stress, and in the worst case, the resistor may be destroyed. It is known that in order to improve the overvoltage characteristic, when the resistor is formed in a meandering shape to extend the overall length thereof, the voltage drop becomes uniform and thus the overvoltage characteristic can be improved.As a prior art of this type of resistor, as shown in FIG. 4, there has been proposed a chip resistor manufactured by the steps of: printing a resistor 102 meandering and changing direction at two positions between a pair of front electrodes 101 disposed at both ends of an insulating substrate 100 and then forming a single trimming groove 103 at the center of the resistor 102 in accordance with a laser trimming method, thereby obtaining the resistor 102 meandering and changing direction at three positions (see Patent Literature 1).As another prior art, as shown in FIG. 5, there has been proposed a chip resistor in which, after forming a resistor 102 by printing, the rectangular regions 102 aconnected to a pair of front electrodes 101 and a substantially S-shaped region 102 blocated between the rectangular regions 102 aare formed between the pair of front electrodes 101 at both ends of an insulating substrate 100, trimming grooves 103 are formed in the rectangular regions 102 aat both ends (see Patent Literature 2).PRIOR ART LISTPATENT LITERATUREPatent Literature 1: JP-H09-205 004 APatent Literature 2: JP-2001-338 801 APatent Literature 3: US 2007 / 0 035 379 A1Patent Literature 4: DE 10 2017 115 774 A1BRIEF DESCRIPTION OF THE INVENTIONTECHNICAL PROBLEMIn Patent Literature 3, a chip resistor is provided that includes a resistor film formed between a pair of terminal electrodes on an upper surface of an insulating substrate. The resistor film is provided with two inwardly directed grooves and two trimming grooves which are alternately provided to give a winding shape to the current path in the resistor film. The two inwardly directed grooves are provided approximately midway between one end edge and the other end edge of the resistor film. The trimming groove is provided between the inner groove and the end edge of the resistor film, while the other trimming groove is provided between the inner groove and the end edge of the resistor film, thereby shortening the time required for trimming adjustment for setting the resistance to a predetermined value and reducing the yield, which in turn lowers the cost.In Patent Literature 4, a chip resistor and a method for manufacturing the chip resistor are disclosed. The chip resistor includes a resistive substance bridging a pair of a first front electrode and a second front electrode. The resistive substance includes a meandering portion connected to the first front electrode and extending in a meandering shape, and an adjusting portion coupled to the meandering portion through a coupling portion. A widthwise central portion of the adjusting portion and the second front electrode are connected to each other by a protrusion portion. A first adjustment groove is formed in the adjustment portion to extend from a lower side to an upper side and reach a position that extends a current path of the resistive substance. In addition, when a virtual area connecting a tip portion of the first matching groove and a connection portion of the protrusion portion to the second front electrode, a second matching groove is formed within a region extending from the lower side of the setting portion but does not reach the virtual area.In the related art described in Patent Literature 1, since the overall length of the resistor 102 is increased by using the printing technique in combination with trimming work, it is possible to improve the overvoltage characteristic. Further, since forming the trimming groove 103 also serves to adjust the resistance value, the accuracy of the resistance value can be improved. However, the trimming groove 103 is provided in a direction in which the cross-sectional area of the current in the resistor 102 is narrowed, and for this reason, the amount of change in the resistance value that increases with an increase in a cutting amount of the trimming groove 103 becomes large. In this way, although the accuracy of the resistance value in Patent Literature 1 can be improved to some extent, the resistance value cannot be finely adjusted with high accuracy.On the other hand, in the related art described in Patent Literature 2, since each of the trimming grooves 103 can be provided in each of the rectangular regions 102 aat the both ends of the resistor 102 with the substantially S-shaped region 102 bbeing interposed therebetween, a setting rate of the resistance value can be increased compared to the chip resistor described in Patent Literature 1. However, the trimming grooves 103 of Patent Literature 2 are also provided in the direction of narrowing the cross-sectional area of the current in the resistor 2, and for this reason, the resistance value cannot be finely adjusted with high accuracy.The present invention has been made in view of the circumstances of the related art. A first object of the present invention is to provide a chip resistor capable of improving the overvoltage characteristic while enabling fine adjustment of a resistance value with high accuracy, and a second object is to provide a manufacturing method thereof.SOLUTION OF PROBLEMTo achieve the first object, the present invention provides a chip resistor comprising: an insulating substrate; a pair of electrodes disposed on the insulating substrate so as to oppose each other with a predetermined interval; and a resistor for bridging between the pair of electrodes, the resistor being provided with trimming grooves for adjusting a resistance value, the resistor having a print-formed body that continuously connects the pair of electrodes, the print-formed body having connection portions each connected to the pair of electrodes and a rectangular-formed adjustment portion, the adjustment portion being located between the connection portions, at least one of the connection portions being a direction-changing meandering portion, a first trimming groove for coarse adjustment being formed in the adjustment portion, in order to extend a current path of the resistor, and a second trimming groove for fine adjustment is formed in the meandering region, wherein when a direction between the pair of electrodes is referred to as an X direction and a direction perpendicular to the X direction is referred to as a Y direction, the meandering region includes an extending region extending in the Y direction, an outer direction changing region extending in the X direction for establishing a connection between the one end of the extending region and one of the pair of electrodes, and an inner direction changing region extending in the X direction for establishing a connection between the other end of the extending region and the adjusting region, wherein the second trimming groove extends away from one of the outer direction changing region and the inner direction changing region as the initial end position in the Y direction, and wherein a distal end of the second trimming groove does not reach an imaginary line connecting the outer direction changing region and the inner direction changing region at the shortest distance.In the chip resistor having the above-described configuration, since the first trimming groove is provided in the adjustment range to lengthen the current path of the resistor, the resistance value is increased depending on an increase in a cutting amount of the first trimming groove. As a result, it is possible to improve the overvoltage characteristic while roughly adjusting the resistance value. Further, since the second trimming groove is provided in a region of the meandering region where a current distribution is small, fine adjustment of the resistance value is possible with high accuracy.In the chip resistor having the above-described configuration, only one of the two connection regions connected to the pair of electrodes may be provided as the direction changing meandering region. However, it is preferable that both the connecting portions are meandering portions having a direction change and the second trimming groove is provided in one of the meandering portions. With this configuration, the overall length of the resistor becomes large, whereby the overvoltage characteristic can be further improved.To achieve the second object, the present invention provides a method of manufacturing a chip resistor, the chip resistor comprising: an insulating substrate; a pair of electrodes disposed on the insulating substrate so as to oppose each other with a predetermined interval; and a resistor for bridging between the pair of electrodes, the resistor being provided with trimming grooves for adjusting a resistance value, the resistor having a print-formed body that continuously connects the pair of electrodes, the print-formed body having connection portions each connected to the pair of electrodes and a rectangular-formed adjustment portion, the adjustment portion being located between the connection portions, at least one of the connection portions being a direction-changing meandering portion, and then, when a direction between the pair of electrodes is referred to as an X direction and a direction perpendicular to the X direction is referred to as a Y direction, the meandering portion includes an extending portion extending in the Y direction, an outer direction changing portion extending in the X direction for establishing a connection between the one end of the extending portion and one of the pair of electrodes, and an inner direction changing portion extending in the X direction for establishing a connection between the other end of the extending portion and the adjusting portion, the manufacturing method including the steps of: forming a first trimming groove for rough adjustment in the adjusting portion to lengthen a current path of the resistor; forming a second trimming groove for fine adjustment extending away from one of the outer direction changing region and the inner direction changing region as the initial end position in the Y direction, and setting a distal end of the second trimming groove at a position not reaching an imaginary line connecting the outer direction changing region and the inner direction changing region at the shortest distance.In the method for manufacturing a chip resistor including the above-described steps, after the print forming of the resistor having a meandering shape in which at least one meandering portion is continuously connected to the adjustment portion, a first trimming groove is formed in the adjustment portion to lengthen the current path of the resistor. With this configuration, the resistance value is increased depending on an increase in the cutting amount of the first trimming groove, and thus it is possible to make a rough adjustment of the resistance value while improving the overvoltage characteristic. Further, since the second trimming groove is disposed in a region of one of the meandering regions in which the current distribution is small after forming the first trimming groove, fine adjustment of the resistance value is possible with high accuracy.ADVANTAGEOUS EFFECTS OF THE INVENTIONAccording to the present invention, a chip resistor can be provided in which overvoltage characteristic can be improved while fine adjustment of resistance value is possible with high accuracy.BRIEF DESCRIPTION OF THE DRAWINGS[FIG. 1 ] FIG. 1 is a plan view of a chip resistor according to a first embodiment of the present invention.[FIGS. 2A-D] Fig. 2 illustrates a process for manufacturing a chip resistor according to the first embodiment.[FIG. 3] FIG. 3 is a plan view of a chip resistor according to a second embodiment of the present invention.[FIG. 4] FIG. 4 shows a plan view of a chip resistor according to the prior art.[FIG. 5 ] FIG. 5 shows a plan view of a chip resistor according to further prior art.DESCRIPTION OF THE EMBODIMENTSHereinafter, embodiments of the present invention will be described with reference to the drawings.FIG. 1 is a plan view of a chip resistor according to a first embodiment of the present invention. As illustrated in FIG. 1, a chip resistor 1 according to the first embodiment is formed to mainly include a rectangular insulating substrate 2, a first front electrode 3 and a second front electrode 4 disposed at both ends of a front surface of the insulating substrate 2 in the longitudinal direction thereof, a resistor 5 disposed on the front surface of the insulating substrate 2 so as to connect the pair of front electrodes 3, 4 to each other, and a protective coating layer (not illustrated) provided covering the resistor 5. Although not shown in the drawings, on a back surface of the insulating substrate 2, a pair of back electrodes corresponding to the front electrodes 3, 4 are provided, and on both end faces of the insulating substrate 2 in the longitudinal direction thereof, end face electrodes for bridging the front electrodes and the corresponding back electrodes are provided.The resistor 5 is formed in a meandering shape in which a first meandering region 6 and a second meandering region 7 are continuously connected to one another at the two ends via an adjustment region 8 arranged in the center. The meandering shape described above is formed by printing a resistor paste. Referring to FIG. 1, when a direction between the first and second front electrodes 3, 4 is referred to as an X direction and a direction perpendicular to the X direction is referred to as a Y direction, the first meandering portion 6 includes an extending portion 6 aextending in the Y direction, an outer direction changing portion 6 bextending in the X direction for establishing connection between a lower end of the extending portion 6 aand the first front electrode 3 illustrated on the left side of FIG. 1, and an inner direction changing portion 6 cextending in the X direction for establishing connection between an upper end of the extending portion 6 aand the setting portion 8, The outer direction change region 6 band the inner direction change region 6 bare the same.The second meandering portion 7 includes a Y-directional extending portion 7 a, an X-directional outer direction changing portion 7 bfor connecting a lower end of the extending portion 7 aand the second front electrode 4 shown on the right side of FIG. 1, and an X-directional inner direction changing portion 7 cfor connecting an upper end of the extending portion 7 aand the setting portion 8. However, the pattern width of the extending portion 7 ais set to be larger (about twice as large) than that of the extending portion 6 aof the first meandering portion 6.The adjusting portion 8 is formed into a rectangular shape, and the pattern width thereof is larger than the pattern width of the first meandering portion 6 and the second meandering portion 7. the inner direction changing portion 6 cof the first meandering portion 6 and the inner direction changing portion 7 cof the second meandering portion 7 are connected to opposite upper end sides of the adjusting portion 8. The adjusting portion 8 is provided with two first trimming grooves 9 formed from the upper side of the adjusting portion 8 along the Y direction. The first trimming grooves 9 have an extension for forming the shape of an I-cut to thereby extend a current path of the resistor 5, thereby roughly adjusting a resistance value of the resistor 5 and thus bringing it close to a target resistance value. Since, when forming the first trimming grooves 9 in the adjusting portion 8, the resistor 5 which has been formed in a shape with the two meandering portions 6, 7 when printing is further meandering and thus changes its direction three times in total, the total length of the resistor 5 can be increased by the amount of the changes in direction.In this connection, the number of the first trimming grooves 9 to be provided in the adjustment portion 8 is not limited to two, and may be one or more than three. In such a case, if the one or more first trimming grooves 9 are formed such that the current path of the adjustment portion 8 having the one or more first trimming grooves 9 is larger than the minimum pattern width of a current path ( 6 a, 6 b, 6 c, 7 b, 7 c) that does not have any trimming grooves formed by printing, the stress in the pattern can be concentrated on portions formed by printing. Thus, even if microcracks are generated in the first trimming grooves 9, it is possible to reduce an adverse effect on resistance value.Further, the second meandering portion 7 is provided with a second trimming groove 10 formed in an L-cut shape from an upper side of the inner direction changing portion 7 ctoward the inside of the extending portion 7 a. A distal end of the second trimming groove 10 is set at a position not crossing an imaginary line E connecting the outer direction change portion 7 band the inner direction change portion 7 con the shortest distance. Here, a region where most current flows in the extending region 7 ais the imaginary line E, and the second trimming groove 10 is provided in a region of the second meandering region 7 in which a current distribution is small. Thus, a change amount of the resistance value corresponding to a cutting amount of the second trimming groove 10 is very small. As a result, the resistance value of the resistor 5 can be finely adjusted to match the target resistance value with high accuracy by the second trimming groove 10.The shape of the second trimming groove 10 is not limited to the shape of an L-cut, and may be an I-cut shape. In this case, when forming the second trimming groove 10 in such a manner that a current path of the extending portion 7 aof the second meandering portion 7 with the second trimming groove 10 is larger than the minimum pattern width of the current path ( 6 a, 6 b, 6 c, 7 b, 7 c) that does not have any trimming grooves formed by printing, the stress in the pattern can be concentrated on portions formed by printing. Thus, even if microcracks are formed in the first trimming grooves 9, an adverse effect on resistance value can be reduced.Next, a manufacturing process of the chip resistor 1 having the above-described configuration will be described with reference to FIG. 2.The first step in the manufacturing process of the chip resistor 1 is to prepare a large-sized substrate from which a plurality of pieces of insulating substrates 2 are obtained. In the large-sized substrate, primary pitch grooves and secondary pitch grooves extending in the longitudinal direction and the transverse direction are provided in advance to form a lattice pattern, each of the lattice regions formed by the primary pitch grooves and the secondary pitch grooves serving as a single chip region. FIG. 2 illustrates a large-sized substrate 2A corresponding to a single chip region as a representative example, but in practice, each step described below is collectively performed with respect to a large-sized substrate corresponding to chip regions present in multiple pieces.That is, as shown in FIG. 2( a), after screen printing Ag-based paste on a front surface of the large-sized substrate 2A, the step of drying and sintering the screen-printed paste is performed to form the first front electrode 3 and the second front electrode 4 (front electrode forming step). Simultaneously with or about the front electrode forming step, after screen printing the Ag-based paste on a back surface of the large-sized substrate 2A, the step of drying and sintering the screen printed paste is performed to perform the pair of back electrodes (not shown) (back electrode forming step).As shown in FIG. 2B, the next step is to screen print resistor paste such as Cu-Ni or ruthenium oxide on the front surface of the large-sized substrate 2A, and then dry and sinter the screen-printed paste to form the resistor 5 whose both ends in the longitudinal direction thereof overlap the first front electrode 3 and the second front electrode 4, respectively (resistor forming step). The resistor 5 includes the first meandering portion 6 connected to the first front electrode 3, the second meandering portion 7 connected to the second front electrode 4, and the rectangular setting portion 8 located between the first front electrode 3 and the second front electrode 4. The first front electrode 3, the second front electrode 4 and the adjusting portion 8 are continuously connected to each other to form meandering shape.In FIG. 2, when an extending direction of the secondary division grooves is referred to as an X direction and an extending direction of the primary division grooves is referred to as a Y direction, the first meandering portion 6 includes the extending portion 6 aextending in the Y direction, the outer direction changing portion 6 bextending in the X direction for establishing a connection between the lower end of the extending portion 6 aand the first front electrode 3 illustrated on the left side of FIG. 2, and the inner direction changing portion 6 cextending in the X direction for establishing a connection between the upper end of the extending portion 6 aand an upper left end of the adjusting portion 8. the second meandering portion 7 includes the extending portion 7 aextending in the Y direction, the X-direction outer direction changing portion 7 bfor connecting the lower end of the extending portion 7 aand the second front electrode 4 shown on the right side of FIG. 2, and the X-direction inner direction changing portion 7 cfor connecting the upper end of the extending portion 7 aand an upper right end of the adjusting portion 8.Next, after forming a precoat layer (not shown) for covering the resistor 5 by screen printing glass paste over the resistor 5 and drying and sintering the printed glass paste, a step of irradiating a laser beam from above the precoat layer is performed to thereby form the two first trimming grooves 9 formed as an I-cut in the setting region 8 (first trimming execution step) as shown in FIG. 2C, to thereby roughly set the resistance value of the resistor 5 to a value slightly lower than the target resistance value. The first trimming grooves 9 are formed to extend from the upper side of the adjusting portion 8 in the Y direction to the lower side thereof. Since the first trimming grooves 9 formed in the above-described manner are provided in the adjusting portion 8, the current path of the resistor 5 is elongated as a whole. Thus, the resistor 5, which has been formed in the printing form with the two meandering regions 6, 7, is formed in this step in a further meandering manner, so that it has a total of three changes in direction. In this connection, it should be noted that the number of the first trimming grooves 9 to be provided in the adjusting portion 8 is not limited to two, and may be one or more than three.Subsequently, as shown in FIG. 2D, the step of forming the second trimming groove 10 is performed with the L-cut forming in the second meandering region 7 (second trimming performing step), thereby fine-adjusting the resistance value of the resistor 5 to match the target resistance value. The second trimming groove 10 is formed to extend from the upper side of the extending portion 7 ain the Y direction to the lower side thereof. Here, care is taken that the distal end of the second trimming groove 10 does not cross the imaginary line E connecting the outer direction change portion 7 band the inner direction change portion 7 con the shortest distance. Here, a region where the second trimming groove 10 is formed is a region of the second meandering region 7 in which the current distribution is small, and thus a resistance value change amount per trimming amount in this region is very small. As a result, the resistance value of the resistor 5 can be finely adjusted by the second trimming groove 10 with high accuracy. In this connection, as long as the distal end of the second trimming groove 10 does not extend beyond or cross the imaginary line E, the shape of the second trimming groove 10 is not limited to the shape of the L-cut, and may be an I-cut shape.Next, the step of screen printing epoxy resin paste over the first trimming grooves 9 and the second trimming groove 10 and heating and curing the screen printed paste is performed to thereby form the protective coating layer (not shown) for covering the resistor 5 as a whole (protective coating layer forming step).The steps up to this time are collectively performed with respect to the large-sized substrate 2A from which a plurality of pieces of insulating substrates are obtained. In the next step, primary breakage processing for dividing the large-sized substrate 2A into stripes along the primary dividing grooves is performed, thereby obtaining stripe-shaped substrates (not shown) provided with chip regions in plural pieces (primary dividing step). Thereafter, the step of applying the Ag paste to divided surfaces of the strip-shaped substrate and then drying and sintering the applied paste or sputtering Ni / Cr thereon is carried out instead of the Ag paste, thereby forming end face electrodes (not shown) for bridging the first and second front electrodes 3, 4 and the corresponding rear electrodes (end face electrode forming step).Then, secondary breakage processing for dividing the strip-shaped substrate along the secondary dividing grooves is performed to obtain a chip unit having the same dimension as the chip resistor 1 (secondary dividing step). The final step is to apply electrolytic plating such as Ni, Au or Sn to both end faces of the insulating substrate 2 in the longitudinal direction thereof for each divided chip unit, thereby forming an outer electrode (not shown) for covering the end face electrodes, the rear electrodes and the first and second front electrodes 3, 4 exposed from the protective film. In this way, the chip resistor 1 as illustrated in FIG. 1 can be provided.As described above, in the chip resistor 1 according to the first embodiment, after the print forming of the resistor 5 having the meandering shape in which the first meandering portion 6 is continuously connected to the second meandering portion 7 across the rectangular-shaped adjustment portion 8, the step of forming the first trimming grooves 9 is performed in the adjustment portion 8. As a result, it is possible to extend the current path of the resistor 5 and improve the overvoltage characteristic while roughly adjusting the resistance value of the resistor 5 to bring it close to the target resistance value. Further, by subsequently forming the second trimming groove 10 in a region of the second meandering region 7 in which the current distribution is small, the resistance value of the resistor can be finely adjusted to match the target resistance value depending on the cutting amount of the second trimming groove 10. As a result, the resistance value can be adjusted with high accuracy while improving the overvoltage characteristic.FIG. 3 is a plan view of a chip resistor 20 according to a second embodiment of the present invention. Elements corresponding to those of FIG. 1 are denoted by the same reference numerals, and repeated explanation thereof is omitted as appropriate.The second embodiment is different from the first embodiment in that the pattern width of the adjusting portion 8 formed narrower by the formation of the first trimming grooves 9 is made substantially equal to that of the pattern of the first meandering portion 6. The remaining configuration of the chip resistor 20 except for those described above is generally the same as that of the chip resistor 1 illustrated in FIG. 1.That is, as shown in FIG. 3, the first groove 9 is formed in a portion of the adjustment portion 8 printed in a rectangular shape, and thus the adjustment portion 8 is formed in a meandering shape. When the pattern width of the first meandering portion 6 is denoted by W, the width dimension of the adjusting portion 8 before the formation of the first trimming groove 9 therein is about 2W. In the second embodiment, by forming the first trimming groove 9 into an I-cut shape for roughly adjusting the resistance value, the rectangular-shaped adjusting portion 8 is formed into a meandering shape so that the width dimension of the adjusting portion 8 is about half, i.e., W.With the chip resistor 20 of the second embodiment formed as described above, since the first trimming groove 9 is formed in the adjustment region 8 printed in a rectangular shape, the pattern width is substantially equal to the width W from the first meandering region 6 through the adjustment region 8 to the inner direction changing region 7 cof the second meandering region 7.In the chip resistor 20 according to the second embodiment, the number of the first trimming grooves 9 to be provided in the adjustment portion 8 may be two or more. In such a case, the width dimension of the adjustment portion 8 at the time of forming it by printing may be changed depending on the number of the first trimming groove(s) 9.Further, in each of the above-described embodiments, the second trimming groove 10 is formed in the second meandering portion 7 from the upper side of the inner direction changing portion 7 cto the inside of the extending portion 7 a. As long as the distal end of the second trimming groove 10 does not extend beyond the imaginary line E connecting the outer direction changing portion 7 band the inner direction changing portion 7 con the shortest distance, the second trimming groove 10 may be provided in the second meandering portion 7 from a lower side of the outer direction changing portion 7 bto the inside of the extending portion 7 a.In addition, in each of the above-described embodiments, an example in which the second trimming groove 10 is provided in the second meandering region 7 connected to the second front electrode 4, which is continuously connected to the first meandering region 6 across the adjustment region 8, has been described. Here, the second trimming groove 10 may also be provided in the first meandering region 6 connected to the first front electrode 3 to perform fine adjustment of the resistance value. In such a case, it is preferable to set the pattern width of the extending portion 6 aof the first meandering portion 6 to be larger than the pattern width of the extending portion 7 aof the second meandering portion 7.Moreover, in each of the above-described embodiments, as each connection portion of the resistor 5 connected to the first front electrode 3 and the second front electrode 4, respectively, the first meandering portion 6 and the second meandering portion 7 are used, both of which have a shape of directional change and a meandering shape, respectively. As one of these connecting portions, a connecting portion having a straight shape without being bent into a curled shape may be used. That is, the chip resistor shown in FIG. 1 may be formed without the extension portion 6 aand the outer direction change portion 6 bof the first meandering portion 6, but is formed to connect between the first front electrode 3 and the adjustment portion 8 using the inner direction change portion 6 cextending in the X direction.LIST OF REFERENCE CHARACTERS1, 20 Chip resistor 2 Insulating substrate 2A Large-sized substrate 3 First front electrode 4 Second front electrode 5 Resistor 6 First meandering region 6 a Erstreckungs region 6 b Äußerer direction changing region 6 c Innerer direction changing region 7 Second meandering region 7 a Erstreckungs region 7 b Äußerer direction changing region 7 c Innerer direction changing region 8 Setting region 9 First trimming groove 10 Second trimming groove E Imaginary line connecting Outer direction changing region and Inner direction changing region at the shortest distance.

Claims

A chip resistor (1, 20) comprising: an insulating substrate (2); a pair of electrodes (3, 4) disposed on the insulating substrate (2) so as to oppose each other with a predetermined interval; and a resistor (5) for bridging between the pair of electrodes (3, 4), the resistor (5) being provided with trimming grooves (9, 10) for adjusting a resistance value, the resistor (5) comprising a print-formed body continuously connecting the pair of electrodes (3, 4), the print-formed body having connection portions each connected to the pair of electrodes (3, 4) and a rectangular-shaped adjustment portion (8), the adjustment portion (8) being located between the connection portions, and varying its direction at at least one of the connection portions around a meandering portion (6, 7) in which a first trimming groove (9) for coarse adjustment is formed in the adjustment region to extend a current path of the resistor (5) and a second trimming groove (10) for fine adjustment is formed in the meandering region (6, 7), wherein when a direction between the pair of electrodes (3, 4) is referred to as an X direction and a direction perpendicular to the X direction is referred to as a Y direction, the meandering region (6, 7) includes an extending region (6a, 7a) extending in the Y direction, an outer direction changing region (6b, 7b) extending in the X direction for establishing connection between the one end of the extending region (6a, 7a) and one of the pair of electrodes (3, 4), and an inner direction changing portion (6c, 7c) extending in the X direction for establishing communication between the other end of the extending portion (6a, 7a) and the adjusting portion (8), wherein the second trimming groove (10) extends away from one of the outer direction changing portion (6b, 7b) and the inner direction changing portion (6c, 7c) as a starting end position in the Y direction, and wherein a distal end of the second trimming groove (10) does not reach an imaginary line (E) connecting the outer direction changing portion (6b, 7b) and the inner direction changing portion (6c, 7c) at the shortest distance.The chip resistor (1, 20) according to claim 1, wherein both the connection portions are direction changing meandering portions (6, 7), and wherein the second trimming groove (9, 10) is formed in one of the meandering portions (6, 7).A method of manufacturing a chip resistor (1, 20), the chip resistor (1, 20) comprising: an insulating substrate (2); a pair of electrodes (3, 4) disposed on the insulating substrate (2) so as to oppose each other with a predetermined interval; and a resistor (5) for bridging between the pair of electrodes (3, 4), the resistor (5) being provided with trimming grooves (9, 10) for adjusting a resistance value, the resistor (5) comprising a print-formed body continuously connecting the pair of electrodes (3, 4), the print-formed body having connection portions each connected to the pair of electrodes (3, 4) and a rectangular-shaped adjustment portion (8), the adjustment portion (8) being located between the connection portions, wherein at least one of the connection portions is a direction changing meandering portion (6, 7), and wherein when a direction between the pair of electrodes (3, 4) is referred to as an X direction and a direction perpendicular to the X direction is referred to as a Y direction, the meandering portion (6, 7) includes a Y direction extending portion (6a, 7a), an X direction outer direction changing portion (6b, 7b) for connecting one end of the extending portion (6a, 7a) and one of the pair of electrodes (3, 4), and an X direction inner direction changing portion (6c, 7c) for connecting the other end of the extending portion (6a, In addition, the method of manufacturing the second trimming groove may include FIG. 7 a) and the adjustment portion (8), the manufacturing method including the steps of: forming a first trimming groove (9) for rough adjustment in the adjustment portion (8) to extend a current path of the resistor (5); forming a second trimming groove (10) for fine adjustment that extends away from one of the outer direction change portion (6 b, 7 b) and the inner direction change portion (6 c, 7 c) as the initial end position in the Y direction; and setting a distal end of the second trimming groove (10) at a position that does not reach an imaginary line (E) connecting the outer direction change portion (6 b, 7 b) and the inner direction change portion (6 c, 7 c) at the shortest distance.

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