JP2024021438A - Resistor and manufacturing method of resistor - Google Patents

Abstract

To provide a resistor whose resistance value hardly changes, and a manufacturing method.SOLUTION: A resistor 1 includes a resistor body 2, a first electrode 3, a second electrode 4, and an oxide film 7. The resistor body 2 is made of metal. The first electrode 3 and the second electrode 4 are located at both ends of the lower surface 21 of the resistor body 2. The oxide film 7 is formed at least adjacent to the first electrode 3 and the second electrode 4 in an exposed surface 22 of the lower surface 21 of the resistor body 2 between the first electrode 3 and the second electrode 4.SELECTED DRAWING: Figure 2

Description

The present disclosure generally relates to a resistor and a method of manufacturing the same, and more particularly relates to a resistor including a resistor and a pair of terminals located at both ends of the resistor and a method of manufacturing the same.

Patent Document 1 discloses a surface-mounted resistor for current detection that is made of metal. In this resistor, the resistor and a pair of electrode terminals are insert-molded with the front and back surfaces of a portion thereof embedded in resin.

Japanese Patent Application Publication No. 11-186010

On the other hand, since resin molding increases the number of parts, resistors that omit this are also known. In the case of such a resistor, the main surface of the resistor is exposed, so the solder may reach the mounting surface of the resistor through the terminal during mounting, and in that case, the solder may conduct to the resistor. It ends up. As a result, the resistance value of the entire resistor changes, resulting in a decrease in current detection accuracy.

An object of the present disclosure is to provide a resistor whose resistance value does not easily change and a method for manufacturing the same.

A resistor according to one aspect of the present disclosure includes a resistor, a pair of electrodes, and an oxide film. The resistor is made of metal. The pair of electrodes are located at both ends of the main surface of the resistor. The oxide film is provided on at least a portion adjacent to the pair of electrodes on an exposed surface between the pair of electrodes on the main surface of the resistor.

A method for manufacturing a resistor according to another aspect of the present disclosure includes a step of arranging a pair of electrodes at both ends of a main surface of a metal resistor; The method includes the step of forming an oxide film on an exposed surface between the electrodes by irradiating at least a portion adjacent to the pair of electrodes with a laser.

According to the resistor manufacturing method according to one aspect of the present disclosure or the resistor manufacturing method according to another aspect of the present disclosure, a resistor whose resistance value does not easily change can be obtained.

FIG. 1 is a longitudinal cross-sectional view of a resistor according to an embodiment. FIG. 2 is a bottom view of the same resistor. FIG. 3 is a longitudinal section of an example of the above resistor. FIG. 4 is a perspective view showing a bonding plate preparation step in the method for manufacturing the same resistor as above. FIG. 5 is a perspective view showing a joining plate dividing step in the method for manufacturing the same resistor as above. FIG. 6 is a perspective view showing an intermediate electrode processing step in the method for manufacturing the same resistor. FIG. 7 is a perspective view showing an oxide film forming step in the method for manufacturing the same resistor. FIG. 8 is a perspective view showing a step of cutting into individual pieces in the method for manufacturing the same resistor.

(Embodiment)
Hereinafter, a resistor and a method for manufacturing the same according to an embodiment will be described with reference to the drawings. Each figure described in the following embodiments is a schematic diagram, and the ratio of the size and thickness of each component does not necessarily reflect the actual size ratio. Moreover, the configuration described in the embodiment below is only an example of the present disclosure. The present disclosure is not limited to the embodiments described below, and various changes can be made depending on the design etc. as long as the effects of the present disclosure can be achieved.

(Embodiment)
(1) Basic configuration of resistor The present disclosure relates to a resistor 1 used in various electronic devices and a method for manufacturing the same.

As shown in FIG. 1, resistor 1 is mounted on printed circuit board 5 via solder 6. As shown in FIG.

The resistor 1 includes a plate-shaped resistor 2, and a first electrode 3 and a second electrode 4 provided at both ends in the longitudinal direction (left-right direction in FIG. 1) of a lower surface 21 (an example of the main surface) of the resistor 2. and. A current flows in the resistor 2 between the first electrode 3 and the second electrode 4 in the longitudinal direction.

The resistor 2 is a plate having a rectangular shape when viewed from above. The resistor 2 is made of an alloy, and includes, for example, a copper-nickel alloy. The size of the resistor 2 in plan view is, for example, 3.2 mm x 6.4 mm or 1.6 mm x 3.2 mm.

The first electrode 3 and the second electrode 4 are formed of a different type of conductor from the resistor 2, and specifically, are made of a metal having a lower resistivity than the resistor 2, such as copper. The first electrode 3 and the second electrode 4 are provided with a tin plating layer by electroplating or dipping. Furthermore, the first electrode 3 and the second electrode 4 are joined to the lower surface 21 at both ends of the resistor 2 in the longitudinal direction by a method such as welding, cladding, or printing. The three sides of the first electrode 3 and the second electrode 4 (excluding the inner side in the longitudinal direction) coincide with the sides of the resistor 2 in plan view. The first electrode 3 and the second electrode 4 are fixed as terminals to the printed circuit board 5 via solder 6.

(2) Oxide Film The resistor 1 has an oxide film 7, as shown in FIG. Oxide film 7 is a film for insulating lower surface 21 of resistor 1 from other conductive materials. The oxide film 7 is formed on the entire exposed surface 22 between the first electrode 3 and the second electrode 4 on the lower surface 21 (an example of the main surface) of the resistor 2 . The oxide film 7 is formed by irradiating a large number of laser pulses without gaps in plan view. Oxide film 7 contains at least one of copper oxide (CuO), copper (I) oxide (Cu ₂ O), and nickel (II) oxide (NiO).

(3) Effect of Resistor FIG. 3 shows a state in which the solder 6 rises from the printed circuit board 5 through the first electrode 3 and reaches the lower surface 21 of the resistor 2 when the resistor 1 is mounted. In this embodiment, the solder 6 is blocked by the oxide film 7, so the solder 6 is not electrically connected to the resistor 2. Therefore, the resistance value of resistor 1 is difficult to change. Conventionally, when the solder 6 comes into contact with the lower surface 21 of the resistor 2, the resistance value of the resistor 1 changes.

(4) Method for manufacturing resistor The method for manufacturing resistor 1 includes the following three steps.

(4-1) First Step The first step is a step of arranging the first electrode 3 and the second electrode 4 at both ends of the lower surface 21 of the resistor 2.

First, as shown in FIG. 4, a flat joining plate 11 is created. The bonding plate 11 is obtained by clad bonding a resistance plate 12 containing a copper-nickel alloy and a copper plate 13. Subsequently, the copper plate 13 is plated with tin.

Next, as shown in FIG. 5, the joining plate 11 is cut into strips to create a narrow long joined body 111. The long joined body 111 consists of a long resistance plate 130 and a long copper plate 131.

Next, as shown in FIG. 6, the long copper plate 131 of the long joined body 111 is cut to form a first intermediate electrode 132 and a second intermediate electrode 133 separated from each other.

(4-2) Second step The second step is to irradiate the exposed surface 22 of the lower surface 21 of the resistor 2 between the first electrode 3 and the second electrode 4 with a laser to remove the oxide film 7. This is the step of forming.

Specifically, as shown in FIG. 7, a laser device 51 is used to irradiate the lower surface 134 of the long resistance plate 130 with laser light 52. In this embodiment, laser irradiation is applied to the entire exposed surface 22. Note that FIG. 7 schematically represents laser irradiation and should not be interpreted in a strict sense. More specifically, laser irradiation melts a portion of the long resistance plate 130 to form a plurality of beads by intermittently repeating pulse irradiation. Note that an example of laser irradiation conditions is a laser power of 300 W, a beam diameter of 0.08 mm, and a speed of 100 mm/s.

As shown in FIG. 2, the plurality of beads are formed at intervals such that they overlap with each other, so that an oxide film 7 with no gaps is obtained. Note that since pulse irradiation is employed, the oxide film 7 can be formed on the exposed surface 22 without bringing the entire long resistance plate 130 into a high temperature state.

(4-3) Third step Finally, as shown in FIG. 8, the resistor 1 is cut out by cutting the long joined body 111 into individual pieces.

(Modified example)
The embodiment described above is only one of various embodiments of the present disclosure. The embodiments described above can be modified in various ways depending on the design, etc., as long as the objective of the present disclosure can be achieved. Modifications of the above embodiment will be listed below. The modified examples described below can be applied in combination as appropriate.

In the embodiment described above, the oxide film 7 was formed on the entire lower surface 21 of the resistor 2, but the oxide film may be formed on a part of the lower surface of the resistor. In particular, the oxide film only needs to be formed on at least a portion adjacent to the pair of electrodes (an area of a predetermined width) on the exposed surface between the pair of electrodes. An example of such a modification will be explained using FIG. 3. When the size of the resistor 2 of the resistor 1 shown in FIG. 3 in plan view is 3.2 mm x 6.4 mm (length D1 of the long side in FIG. 3), the length D2 of each of the electrodes 3 and 4 in the longitudinal direction is If the width is 1.2 mm, the longitudinal widths D3 and D4 of the oxide film 7 are each in the range of 0.5 mm to 1.5 mm.

The materials of the resistor and electrodes are not limited to the embodiments described above.

The shape of the electrode is also not particularly limited. The electrode may have a portion that protrudes from the resistor in the longitudinal direction or the lateral direction when viewed in plan.

A third step (cutting out individual pieces) may be performed before the second step (laser irradiation).

(mode)
The following aspects are disclosed herein.

A resistor (1) according to a first aspect includes a resistor (2), a pair of electrodes (3, 4), and an oxide film (7). The resistor (2) is made of metal. A pair of electrodes (3, 4) are located at both ends of the lower surface (21) of the resistor (2). The oxide film (7) is adjacent to at least one pair of electrodes (3, 4) on the exposed surface (22) between the pair of electrodes (3, 4) on the lower surface (21) of the resistor (2). provided in the section.

According to this aspect, even when the resistor (1) is mounted, the solder (6) rises from the printed circuit board (5) through the pair of electrodes (3, 4) and reaches the bottom surface (21) of the resistor (2). Even if the solder (6) reaches the resistor (2), it is blocked by the oxide film (7), so the solder (6) is not electrically connected to the resistor (2). Therefore, the resistance value of the resistor (1) is difficult to change.

In the resistor (1) according to the second embodiment, the oxide film (7) is formed over the entire exposed surface (22) in the first embodiment.

According to this aspect, the resistance value of the resistor (1) becomes more difficult to change.

In the resistor (1) according to the third aspect, in the first or second aspect, the resistor (2) includes a copper-nickel alloy, and the pair of electrodes (3, 4) includes copper.

According to this aspect, a resistor (1) whose resistance value hardly changes can be obtained.

In the resistor (1) according to the fourth aspect, in any one of the first to third aspects, the oxide film (7) is at least one of copper oxide, copper (I) oxide, and nickel (II) oxide. Including one.

According to this aspect, a resistor (1) whose resistance value hardly changes can be obtained.

A method for manufacturing a resistor (1) according to a fifth aspect includes the steps of: arranging a pair of electrodes (3, 4) at both ends of a lower surface (21) of a metal resistor (2); On the exposed surface (22) between the pair of electrodes (3, 4) on the lower surface (21) of (2), laser irradiation is performed on at least a portion adjacent to the pair of electrodes (3, 4) to oxidize it. forming a membrane (7).

According to this aspect, even when the resistor (1) is mounted, the solder (6) rises from the printed circuit board through the pair of electrodes (3, 4) and reaches the bottom surface (21) of the resistor (2). However, the solder (6) is not electrically connected to the resistor (2) because it is blocked by the oxide film (7). Therefore, the resistance value of the resistor (1) is difficult to change.

In the method for manufacturing a resistor (1) according to the sixth aspect, in the fifth aspect, laser irradiation is performed on the entire exposed surface (22).

According to this aspect, the resistance value of the resistor (1) becomes more difficult to change.

In the seventh method for manufacturing a resistor, in the fifth or sixth aspect, the laser irradiation is repeated by pulse irradiation.

According to this aspect, the oxide film (7) can be formed on the exposed surface (22) without bringing the entire resistor (2) into a high temperature state.

1 Resistor 2 Resistor 3 First electrode 4 Second electrode 6 Solder 7 Oxide film 21 Bottom surface (principal surface)

Claims (7)

a metal resistor,
a pair of electrodes located at both ends of the main surface of the resistor;
an oxide film provided at least in a portion adjacent to the pair of electrodes on an exposed surface between the pair of electrodes on the main surface of the resistor;
A resistor. the oxide film is formed on the entire exposed surface;
A resistor according to claim 1. The resistor includes a copper-nickel alloy,
the pair of electrodes include copper;
A resistor according to claim 1 or 2. The oxide film contains at least one of copper oxide, copper (I) oxide, and nickel (II) oxide,
A resistor according to claim 3. arranging a pair of electrodes at both ends of the main surface of the metal resistor;
forming an oxide film on an exposed surface between the pair of electrodes of the main surface of the resistor by irradiating at least a portion adjacent to the pair of electrodes with a laser;
A method of manufacturing a resistor, including: The laser irradiation is performed on the entire exposed surface,
A method for manufacturing a resistor according to claim 5. The laser irradiation repeats pulse irradiation,
A method for manufacturing a resistor according to claim 5 or 6.

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