To provide a chip resistor in which a resistive element can be surely protected from an external environment and which is also excellent in corrosion resistance, a chip resistor 1 is configured to include an insulating substrate 2, a pair of front electrode 3 provided on opposite end portions of a front surface of the insulating substrate 2, a pair of back electrodes 7 provided on opposite end portions of a back surface of the insulating substrate 2, a resistive element 4 provided to extend onto the two front electrodes 3, a first insulating layer 5 covering the resistive element 4, a second insulating layer 6 made of a resin material to cover the first insulating layer 5, end surface electrodes 8 establishing electrical continuity between the front electrodes 3 and the back electrodes 7, plating layers 9 covering the end surface electrodes 8, etc. Rough surface portions 6a made rougher in surface roughness than any other portion of the second insulating layer 6 are formed at opposite end portions of the second insulating layer 6. End portions of the end surface electrodes 8 and the plating layers 9 are brought into tight contact with the rough surface portions 6a respectively.

To provide a chip resistor in which a resistive element can be surely protected from an external environment and which is also excellent in corrosion resistance, a chip resistor 1 is configured to include an insulating substrate 2, a pair of front electrode 3 provided on opposite end portions of a front surface of the insulating substrate 2, a pair of back electrodes 7 provided on opposite end portions of a back surface of the insulating substrate 2, a resistive element 4 provided to extend onto the two front electrodes 3, a first insulating layer 5 covering the resistive element 4, a second insulating layer 6 made of a resin material to cover the first insulating layer 5, end surface electrodes 8 establishing electrical continuity between the front electrodes 3 and the back electrodes 7, plating layers 9 covering the end surface electrodes 8, etc. Rough surface portions 6a made rougher in surface roughness than any other portion of the second insulating layer 6 are formed at opposite end portions of the second insulating layer 6. End portions of the end surface electrodes 8 and the plating layers 9 are brought into tight contact with the rough surface portions 6a respectively.

The invention is to provide a resistor trimming method capable of adjusting a resistance value with ultrahigh precision and having excellent production efficiency. To achieve the object, a start point (S1) at a distance from a resistor (4) is irradiated with laser light while probes are brought into contact with a pair of surface electrodes (3) to measure a resistance value of the resistor (4). The place irradiated with the laser light is scanned so that a first trimming groove (5) extending in a direction perpendicular to a current direction can be formed in the resistor (4). Then, the place irradiated with the laser light is returned by a predetermined amount from an end point (first turning point (T1)) of the first trimming groove (5) to be set as a second turning point (T2). With the second turning point (T2) as a start point, scanning and cutting is performed to forma second trimming groove (6). Thus, the resistance value of the resistor (4) is adjusted to a target resistance value with high precision.

The invention is to provide a resistor trimming method capable of adjusting a resistance value with ultrahigh precision and having excellent production efficiency. To achieve the object, a start point (S1) at a distance from a resistor (4) is irradiated with laser light while probes are brought into contact with a pair of surface electrodes (3) to measure a resistance value of the resistor (4). The place irradiated with the laser light is scanned so that a first trimming groove (5) extending in a direction perpendicular to a current direction can be formed in the resistor (4). Then, the place irradiated with the laser light is returned by a predetermined amount from an end point (first turning point (T1)) of the first trimming groove (5) to be set as a second turning point (T2). With the second turning point (T2) as a start point, scanning and cutting is performed to forma second trimming groove (6). Thus, the resistance value of the resistor (4) is adjusted to a target resistance value with high precision.

There is provided a resistor in which a first resistive part of a resistive element that electrically conducts between a pair of electrodes formed on either end of an insulating substrate has a meandering pattern meandering on the substrate surface and a swelling pattern that has a form in which a part of the meandering pattern swells out from the stroke width of the meandering pattern, a second resistive part that is electrically connected in series to the first resistive part is shorter than the entire length of the first resistive part, and has a wider width than the stroke width of the meandering pattern, and a trimming groove is formed in at least either the swelling pattern or the second resistive part. This can improve resistance accuracy and provide a high voltage resistor with high withstand voltage property.

There is provided a resistor in which a first resistive part of a resistive element that electrically conducts between a pair of electrodes formed on either end of an insulating substrate has a meandering pattern meandering on the substrate surface and a swelling pattern that has a form in which a part of the meandering pattern swells out from the stroke width of the meandering pattern, a second resistive part that is electrically connected in series to the first resistive part is shorter than the entire length of the first resistive part, and has a wider width than the stroke width of the meandering pattern, and a trimming groove is formed in at least either the swelling pattern or the second resistive part. This can improve resistance accuracy and provide a high voltage resistor with high withstand voltage property.

In certain embodiments, a method comprises ablating, by a laser set to a first power level, a first area of a polyimide base substrate and forming, by ablating the first area of the polyimide base substrate, a first carbonaceous material film comprising a first specific resistive value. The method further comprises ablating, by the laser set to a second power level, a second area of the polyimide base substrate and forming, by ablating the second area of the polyimide base substrate, a second carbonaceous material film comprising a second specific resistive value. A tapered resistive material is produced by forming the first carbonaceous material film comprising the first specific resistive value and the second carbonaceous material film comprising the second specific resistive value.

A resistance adjustment circuit has a plurality of conductive patterns placed in parallel to one another on a flat surface formed from an insulating body so as to extend in a first direction, and also has a resistive element that spans two conductive patterns and is electrically connected to the conductive patterns at superimposing parts superimposed on the conductive patterns. A plurality of resistive elements are provided so as to be spaced in the first direction and are connected in parallel to one another across the two conductive patterns. Part of the conductive patterns can be selectively cut between the superimposing parts of resistive elements disposed adjacently. The combined resistance of the resistance adjustment circuit can be adjusted by reducing parallel connections of resistive elements or combining parallel connections of resistive elements with their series connections.

A resistance adjustment circuit has a plurality of conductive patterns placed in parallel to one another on a flat surface formed from an insulating body so as to extend in a first direction, and also has a resistive element that spans two conductive patterns and is electrically connected to the conductive patterns at superimposing parts superimposed on the conductive patterns. A plurality of resistive elements are provided so as to be spaced in the first direction and are connected in parallel to one another across the two conductive patterns. Part of the conductive patterns can be selectively cut between the superimposing parts of resistive elements disposed adjacently. The combined resistance of the resistance adjustment circuit can be adjusted by reducing parallel connections of resistive elements or combining parallel connections of resistive elements with their series connections.

A compact and refined chip resistor, with which a plurality of types of required resistance values can be accommodated readily with the same design structure, was desired. The chip resistor is arranged to have a resistor network on a substrate. The resistor network includes a plurality of resistor bodies arrayed in a matrix and having an equal resistance value. A plurality of types of resistance units are respectively arranged by one or a plurality of the resistor bodies being connected electrically. The plurality of types of resistance units are connected in a predetermined mode using connection conductor films and fuse films. By selectively fusing a fuse film, a resistance unit can be electrically incorporated into the resistor network or electrically separated from the resistor network to make the resistance value of the resistor network the required resistance value.