JP3177429B2 - Structure of chip type resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a chip type resistor in which a resistive film is formed on an upper surface of a chip type insulating substrate.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture this type of chip type resistor 1, it is necessary to: First, as shown in FIG. 10, upper surface electrode films 3 are formed on both left and right ends of the upper surface of the chip-type insulating substrate 2 by applying a material paste thereof, drying and firing. . As shown in FIG. 11, a resistive film 4 is formed on the upper surface of the insulating substrate 2 so that both ends of the resistive film 4 partially overlap the upper electrode films 3, and a material paste is applied and dried. -It is formed by firing. . As shown in FIG. 12, a primary cover coat 5 made of glass or the like is formed on the upper surface of the insulating substrate 2 by applying a material paste, drying and baking so as to cover the entire resistive film 4. . As shown in FIG. 1, the primary cover coat 5 and the resistance film 4
As shown by a two-dot chain line in FIG. 2, a trimming groove 6 is formed by a laser or the like, so that the total resistance value of the resistance film 4 is adjusted to fall within a predetermined resistance value range. . As shown in FIG. 13, a secondary cover coat 7 of glass or the like is formed on the upper surface of the primary cover coat 5 by applying a paste of the material, drying and firing. . As shown in FIG. 14, an end surface electrode film 8 is provided on the end surfaces 2a at the left and right ends of the insulating substrate 2 as shown in FIG.
It is formed by applying the material paste, drying, and baking so that the material paste is electrically connected to the material paste. . Next, a metal plating layer such as nickel is formed on the surfaces of both upper electrode films 3 and both end electrode films 8 to form a metal plating layer. (For example,
JP-A-56-148804, etc.).

A chip type resistor 1 according to this manufacturing method comprises a pair of left and right upper surface electrode films 3 formed on both upper and lower ends on the upper surface of a chip type insulating substrate 2, and both ends are partially formed on the upper surface electrode films. A resist film 4 formed so as to overlap, a cover coat 7 formed so as to cover the entire resist film,
The structure has an end face electrode film 8 formed on both right and left end faces 2 a of the insulating substrate 2 so as to be electrically connected to the upper face electrode film 3.

[0004]

However, in the chip type resistor 1 having this structure, the upper surface of the cover coat 7 for covering the resistive film 4 on the upper surface of the insulating substrate 2 is formed as shown in FIG.
As shown in FIG. 7, the projection protrudes considerably higher than the upper surfaces of the upper electrode films 3, and a large step is formed between the upper surface of the cover coat 7 and the upper surfaces of the upper electrode films 3 on both sides thereof.

Therefore, when the chip-type resistor 1 is automatically mounted on a printed wiring board or the like, the chip-type resistor 1 is connected to a vacuum-suction type collet as shown in FIG. At the time of suction at A, the collet A is slightly displaced in the lateral direction as shown by a two-dot chain line in FIG. 15 and, because of a large step between the upper surface of the cover coat 7 and the upper electrode film 3, Since a large amount of atmospheric air is sucked, there has been a problem that a suction mistake that cannot be performed occurs or a situation occurs in which the air falls during lifting.

Further, in the chip type resistor 1 having the structure according to the conventional manufacturing method, as described above, the upper surface of the cover coat 7 is formed to project considerably higher than the upper surfaces of both upper electrode films 3. By this, this chip type resistor 1
As shown in FIG. 16, after being turned upside down on the printed board B, both upper electrode films 3 and both end electrode films 8 are formed.
Is mounted to the wiring patterns B1 and B2 on the printed circuit board B by soldering, the cover coat 7 projecting considerably higher than the upper surfaces of both upper electrode films 3
Comes into contact with the printed circuit board B first, and a large gap is formed between the upper electrode films 3 and the wiring patterns B1 and B2. However, as shown by the two-dot chain line, there is also a problem that one end thereof may be inclined so as to be lifted from the printed circuit board B, and a situation in which solder mounting may not be performed may occur.

An object of the present invention is to provide a structure of a chip-type resistor in which the above-mentioned problem does not occur.

[0008]

In order to achieve this technical object, the present invention provides a method of forming a pair of left and right upper electrode films formed on both right and left ends of an upper surface of a chip-type insulating substrate, and having both upper and lower electrode films on both ends. and forming a resistor film so as to overlap film a part, a cover coat is formed to cover the entire of the resistive film was formed to conduct to the upper electrode film on the left and right end surfaces of the insulating substrate In a chip type resistor having an end surface electrode film, an auxiliary upper surface electrode film is provided on a portion of the upper surface of the both upper surface electrode films where the cover coat does not overlap, and a part of the both auxiliary upper surface electrode films is formed of the cover coat. Is formed so as to overlap with the inclined portions at both ends in "."
It was configured to say.

[0009]

As described above, when forming the auxiliary upper surface electrode film on the upper surfaces of both upper electrode films, a part of the auxiliary upper surface electrode film is partially covered with the inclined portions at both ends in the cover coat.
By that as overlying the upper surface of the auxiliary upper electrode film, beyond the cover coat thickness can be brought close to the upper surface of the cover coat, in other words, the upper surface of the auxiliary upper electrode film, Since the step between the upper surface of the cover coat and the cover upper coat can be reduced or almost eliminated, and the gap between the auxiliary upper surface electrode film and the cover coat can be prevented,
At the time of automatic mounting of this chip type resistor, when sucking with the vacuum suction type collet, even if the collet shifts in the horizontal direction, it can prevent a large amount of atmospheric air from being sucked, causing suction error and lifting It is possible to surely prevent a drop on the way.

In addition, the step between the upper surface of the auxiliary upper electrode film and the upper surface of the cover coat can be reduced or almost eliminated. When soldering upside down, it is possible to reliably prevent one end of the soldering from being lifted from the printed circuit board, and to reliably solder the printed circuit board or the like.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. A chip type resistor 10 according to an embodiment of the present invention has a structure as shown in FIG.

That is, the chip type resistor 10 is a chip type insulating substrate 11 made of ceramic or the like.
And a pair of left and right upper electrode films 12 formed on both left and right ends of the upper surface of the insulating substrate 11, and a resistance film 1 formed so that both ends partially overlap the upper electrode films 12.
3, a primary cover coat 14 formed so as to cover the entire resistive film 13, and a primary cover coat 14
And a second cover coat 16 formed on the upper surface of both upper electrode films 12.
An auxiliary top electrode film 17 of an appropriate thickness configured so as to be in close contact with the secondary cover coat 16 at a portion where the upper electrode film 6 does not overlap, and the upper electrode film 1 on the left and right end surfaces 11a of the insulating substrate 11.
2 and the end surface electrode film 18 formed so as to be electrically connected to the auxiliary upper surface electrode film 17, and furthermore, the nickel plating layer 19 formed on the both end surface electrode film 18 and the surfaces of the auxiliary upper surface electrode films 17 and the solder plating And a metal plating layer 21 composed of a layer 20 and the like.

Then, the chip type resistor 10 having this configuration
Is manufactured by the method described below. . First, as shown in FIG. 2, upper and lower electrode films 12 are formed on both left and right ends of the upper surface of the insulating substrate 11 by applying a material paste, drying and firing. . As shown in FIG. 3, a resistive film 13 is formed on the upper surface of the insulating substrate 11 such that both ends of the resistive film 13 partially overlap the upper electrode films 12, and a material paste is applied and dried. -It is formed by firing. . As shown in FIG. 4, a primary cover coat 14 made of glass or the like is formed on the upper surface of the insulating substrate 11 by applying a material paste, drying and baking so as to cover the entire resistive film 13. . The primary cover coat 14 and the resistance film 13
As shown by the two-dot chain line in FIG. 4, the trimming groove 15 is formed by a laser or the like, so that the total resistance value of the resistance film 13 is adjusted to fall within a predetermined resistance value range. . As shown in FIG. 5, a secondary cover coat 16 of glass or the like is formed on the upper surface of the primary cover coat 14 by applying a material paste, drying and firing.

In forming the secondary cover coat 16,
Then apply the material paste and then dry and bake
At this time, part of the material paste on the upper electrode film 12 side
Is softened and flows to the upper electrode film 12 side.
Thus, both ends of the secondary cover coat 16 are inclined.
You . . As shown in FIG. 6, an auxiliary upper surface electrode film 17 having an appropriate thickness is formed on the upper surfaces of the upper electrode films 12, and the auxiliary upper surface electrode film 17 is formed on both ends of the secondary cover coat 16.
Is formed by applying the material paste, drying and baking so as to partially overlap the inclined portion of the material. In this case, the film thickness of both auxiliary upper surface electrode films 17 is set such that at least a portion of the upper surface of the auxiliary upper surface electrode film 17 adjacent to the secondary cover coat 16 is the second cover coat 1.
6 so as to approach the upper surface. . End faces 11a at both left and right ends of the insulating substrate 11
Next, as shown in FIG. 7, the end face electrode film 18 is formed by applying a material paste, drying and firing so as to be electrically connected to the upper electrode film 12 and the auxiliary upper electrode film 17. I do. . Next, after plating with nickel, plating with solder is performed to form a nickel plating layer 19 and a solder plating layer on the surfaces of the auxiliary upper surface electrode films 17 and both end surface electrode films 18 as shown in FIG. A metal plating layer 21 made of 20 or the like is formed.

As described above, the auxiliary upper electrode film 17 is provided on the upper surfaces of the upper electrode films 12, and at least a portion of the upper surface of the auxiliary upper electrode film 17 adjacent to the secondary cover coat 16 is the secondary cover coat 16. , The step between the upper surface of the auxiliary upper electrode film 17 and the upper surface of the secondary cover coat 16 can be reduced or almost eliminated.

In addition, when forming the auxiliary upper electrode film 17, a part of the auxiliary upper electrode film 17 is
Weight on the inclined portions at both ends of the secondary cover coat 16.
As a result, the upper surface of the auxiliary upper electrode film 17 can be brought closer to the upper surface of the secondary cover coat 16 beyond the thickness of the secondary cover coat 16, in other words, the auxiliary upper electrode film 17 Upper surface and secondary cover coat 1
6 can be reduced or almost eliminated, and a gap between the auxiliary upper electrode film 17 and the secondary cover coat 16 can be prevented. This chip type resistor 1
0 for automatic mounting on a printed circuit board, etc.
As shown in FIG. 8, when suction is performed by the vacuum suction type collet A, even if the collet A is shifted in the horizontal direction as shown by a two-dot chain line in FIG. 8, a large amount of atmospheric air is not sucked. It is possible to reliably prevent a suction error from occurring or dropping during lifting.

In addition, the step between the upper surface of the auxiliary upper electrode film 17 and the upper surface of the secondary cover coat 16 can be reduced or almost eliminated. As shown in FIG. 9, after the flip-flop 10 is placed upside down on the upper surface of the printed circuit board B and then mounted on the wiring patterns B1 and B2 on the upper surface of the printed circuit board B by soldering, Since it is possible to avoid forming a large gap between the upper surface electrode 17 and both the wiring patterns B1 and B2 on the printed circuit board B, the chip resistor 10
It is possible to reliably prevent the one end from inclining so as to rise from the printed circuit board B, and it is possible to surely mount the printed circuit board or the like by soldering.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a chip resistor according to an embodiment of the present invention.

FIG. 2 is a perspective view when an upper electrode film is formed on an insulating substrate in manufacturing the chip resistor of the present invention.

FIG. 3 is a perspective view when a resistive film is formed on the insulating substrate.

FIG. 4 is a partially cutaway perspective view when a primary cover coat is formed on the insulating substrate.

FIG. 5 is a perspective view when a secondary cover coat is formed on the insulating substrate.

FIG. 6 is a perspective view when an auxiliary upper electrode film is formed on the insulating substrate.

FIG. 7 is a perspective view when an end face electrode film is formed on the insulating substrate.

FIG. 8 is a diagram showing a state in which a chip-type resistor according to the present invention is sucked by a vacuum suction type collet.

FIG. 9 is a diagram showing a case where the chip-type resistor according to the present invention is mounted upside down on a printed circuit board.

FIG. 10 is a perspective view when an upper electrode film is formed on an insulating substrate in manufacturing a conventional chip-type resistor.

FIG. 11 is a perspective view when a resistive film is formed on the insulating substrate.

FIG. 12 is a partially cutaway perspective view when a primary cover coat is formed on the insulating substrate.

FIG. 13 is a perspective view when a secondary cover coat is formed on the insulating substrate.

FIG. 14 is a perspective view when an end face electrode film is formed on the insulating substrate.

FIG. 15 is a diagram illustrating a state in which a conventional chip-type resistor is sucked by a vacuum suction-type collet.

FIG. 16 is a diagram showing a case where a conventional chip-type resistor is mounted upside down on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Chip type resistor 11 Insulating substrate 12 Upper surface electrode film 13 Resistive film 14 Primary cover coat 15 Trimming groove 16 Secondary cover coat 17 Auxiliary upper surface electrode film 18 End surface electrode film 19 Nickel plating layer 20 Solder plating layer 21 Metal plating layer

Claims (2)

(57) [Claims] 1. A pair of left and right upper surface electrode films formed on both right and left ends of an upper surface of a chip-type insulating substrate; a resistance film formed so that both ends partially overlap the upper surface electrode films; A chip coat resistor having a cover coat formed so as to cover the entirety of the substrate, and end face electrode films formed on both right and left end faces of the insulating substrate so as to be electrically connected to the upper face electrode film. A portion of the upper surface of the cover coat where the cover coat does not overlap is provided with an auxiliary upper electrode film, and both of the auxiliary upper electrode films are partially inclined at both ends of the cover coat.
Characterized in that it is formed so as to overlap with the chip resistor. 2. The method according to claim 1, wherein the thicknesses of the auxiliary upper surface electrode films are adjusted such that at least a portion of the upper surface of the auxiliary upper surface electrode film adjacent to the cover coat approaches the upper surface of the cover coat. The structure of a chip-type resistor characterized by the following.