JP2023135909A - vibration motor - Google Patents

Abstract

To provide a vibration motor that is down-sized and high in efficiency.SOLUTION: A vibration motor comprises a vibrating body including a permanent magnet, a substrate 20 having a wiring pattern 23 formed thereon, and a coil 30 provided on the substrate 20 and electrically connected to the wiring pattern 23 formed on the substrate 20. The coil 30 includes an inner coil 31 and an outer coil 32 provided around the inner coil 31. A winding-start end part 33a and a winding-finish end part 33b of a first winding wire forming the inner coil 31 are connected to the wiring pattern 23, on the inside of the coil 30, and a winding-start end part 34a and a winding-finish end part 34b of a second winding wire forming the outer coil 32 are connected to the wiring pattern 23, on the inside of the coil 30.SELECTED DRAWING: Figure 6

Description

The present invention relates to a vibration motor.

Today, vibration motors (sometimes called "vibration actuators") are built into various electronic devices such as smartphones and tablet devices. An example of a vibration actuator built into an electronic device is described in Patent Document 1.

The vibration actuator described in Patent Document 1 includes a vibrating part including a magnet, a leaf spring supporting the vibrating part, a coil disposed near the vibrating part, and a flexible substrate electrically connected to the coil. ,have.

Japanese Patent Application Publication No. 2002-200460

Vibration motors are required to be smaller and more efficient.

An object of the present invention is to provide a small and highly efficient vibration motor.

A vibration motor according to an embodiment includes a vibrating body including a permanent magnet, a substrate on which a wiring pattern is formed, and the vibration motor is provided on the substrate and electrically connected to the wiring pattern formed on the substrate. It has a coil. The coil includes an inner coil and an outer coil provided around the inner coil. The wiring pattern includes a first wiring pattern and a second wiring pattern that cross the inner coil and the outer coil and extend inside and outside the coil. A winding start end of the first winding forming the inner coil and a winding start end of the second winding forming the outer coil are connected to the first wiring pattern inside the coil. Connected. Further, a winding end portion of the first winding forming the inner coil and a winding end portion of the second winding forming the outer coil are connected to the second wiring inside the coil. connected to the pattern.

According to the present invention, a small and highly efficient vibration motor is realized.

FIG. 1 is a perspective view showing the external appearance of a vibration motor. FIG. 2 is a perspective view showing the inside of the vibration motor. FIG. 3 is an exploded perspective view of the vibration motor. FIG. 4 is an exploded perspective view of the substrate. FIG. 5A is an exploded perspective view of the coil. FIG. 5B is a top view of the coil. FIG. 6 is a perspective view showing a connection state between a wiring pattern and a coil. FIG. 7 is a plan view showing the connection state between the wiring pattern and the coil. FIG. 8 is a plan view showing a modified example of the wiring pattern. FIG. 9 is a plan view showing another modified example of the wiring pattern.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings referred to to describe the embodiments, the same reference numerals are used for the same or substantially the same configurations and elements. In addition, as a general rule, the structure or elements that have been explained once will not be explained repeatedly.

<Overview of vibration motor>
FIG. 1 is a perspective view showing the appearance of a vibration motor 1 according to this embodiment. FIG. 2 is a perspective view showing the inside of the vibration motor 1. As shown in FIG. FIG. 3 is an exploded perspective view of the vibration motor 1.

The vibration motor 1 has a housing 10 that constitutes an outer shell. The housing 10 is formed of a metal plate (for example, a stainless steel plate). More specifically, the housing 10 includes a cover 11 formed of a metal plate and a base plate 12 formed of a metal plate. The cover 11 has a box shape with one side open. The base plate 12 closes the opening surface of the cover 11.

Components of the vibration motor 1 such as a substrate 20, a coil 30, a vibrating body 40, and an elastic member 50 are housed inside the housing 10. The vibrating body 40 reciprocates inside the housing 10 in the longitudinal direction of the housing 10 (the long side direction of the base plate 12). From another perspective, the vibrating body 40 generates vibrations in the longitudinal direction of the housing 10. That is, the vibration motor 1 according to this embodiment is a linear type vibration motor.

<Housing>
The housing 10 has a front face part 13 and a back face part 14 facing each other, a top face part 15 and a bottom face part 16 facing each other, and a right side face part 17 and a left side face part 18 facing each other. As described above, the vibrating body 40 reciprocates in the longitudinal direction of the housing 10. From another perspective, the vibrating body 40 reciprocates in the direction in which the right side surface portion 17 and the left side surface portion 18 face each other.

Although not shown, a pair of restriction parts are provided inside the casing 10. These regulating portions are arranged on both sides of the vibrating body 40 in the vibration direction of the vibrating body 40. From another perspective, the vibrating body 40 is arranged between a pair of opposing restriction parts. As a result, the vibration of the vibrating body 40 is limited within a predetermined range. In other words, the vibrating body 40 vibrates within the range of the opposing interval between the pair of regulating parts. However, under normal vibration conditions, the vibrating body 40 does not come into contact with the regulating portion. If the vibrating body 40 vibrates or is displaced more than usual for some reason, the vibrating body 40 comes into contact with one of the regulating portions, and excessive vibration or displacement of the vibrating body 40 is prevented.

Each part of the housing 10 (the front part 13 , the back part 14 , the top part 15 , the right side part 17 , and the left side part 18 ) except the bottom part 16 is formed by the cover 11 . On the other hand, the lower surface portion 16 of the housing 10 is formed by the base plate 12. In addition, in the following description, the front part 13, the back part 14, the right side part 17, and the left side part 18 may be collectively called a "peripheral part."

There is also an embodiment in which the peripheral surface portion is formed of a metal plate different from the cover 11 and the base plate 12. For example, in some embodiments, the peripheral surface portion is formed by a band-shaped metal plate whose both ends are fixed to each other. In this embodiment, the upper surface portion 15 is formed by a flat metal plate punched into a rectangular or substantially rectangular shape.

<Vibrating body>
The vibrating body 40 includes a weight 41, a back yoke 42, and a permanent magnet 43. Note that in FIG. 2, the back yoke 42 is omitted for convenience. The weight 41 is a block of metal alloy (eg, tungsten alloy). Two magnet accommodating parts 44 are formed in the center of the weight 41. Each magnet accommodating portion 44 is a rectangular or approximately rectangular hole that penetrates the weight 41 .

A permanent magnet 43 is housed in each magnet housing section 44 . Each permanent magnet 43 has a prismatic shape. More specifically, the permanent magnet 43 has a shape and dimensions that allow it to fit within the magnet accommodating portion 44 almost without any gaps.

When current is supplied to the coil 30 (voltage is applied to the coil 30), the interaction between the magnetic field generated around the coil 30 and the magnetic field generated around the permanent magnet 43 causes the permanent magnet 43 to be The vibrating body 40 vibrates.

The back yoke 42 is stacked on the weight 41 and closes one opening of the magnet accommodating portion 44 . As a result, the back yoke 42 overlaps the permanent magnet 43 housed in the magnet housing section 44. The back yoke 42 forms a magnetic circuit with the permanent magnet 43 and increases the power of the vibration motor 1.

<Elastic member>
The elastic member 50 is a leaf spring processed into a predetermined shape. A first fixing portion 51 fixed to the housing 10 is provided at one end of each elastic member 50 . On the other hand, a second fixing part 52 fixed to the vibrating body 40 is provided on the other end side of each elastic member 50. The first fixing portion 51 of the elastic member 50 is, for example, welded to the inner surface of the housing 10. Further, the second fixing portion 52 of the elastic member 50 is, for example, welded to the outer surface of the weight 41.

In the following description, the first fixing portion 51 may be referred to as the “base end portion 51” and the second fixing portion 52 may be referred to as the “tip portion 52”. Further, the portion between the base end portion 51 and the distal end portion 52 may be referred to as a “center portion 53”. From another perspective, the side where the first fixing part 51 is provided is the proximal end side of the elastic member 50, and the side where the second fixing part 52 is provided is the distal end side of the elastic member 50.

A proximal end 51 and a distal end 52 of each elastic member 50 are bent at a right angle or approximately at a right angle with respect to a central portion 53 . As a result, each elastic member 50 has a U-shaped or substantially U-shaped appearance.

The vibrating body 40 is disposed between two opposing elastic members 50 and is supported by these elastic members 50 so as to be able to vibrate. From another perspective, each elastic member 50 is a support member that supports the vibrating body 40 so as to vibrate with respect to the housing 10.

Note that there is also an embodiment in which damper rubber is attached to each elastic member 50. The damper rubber is attached to the center portion 53 of the elastic member 50, for example. The damper rubber attached to the elastic member 50 shortens the time required for the vibrations of the vibrating body 40 to be damped.

<Substrate>
FIG. 4 is an exploded perspective view of the substrate 20. The board 20 is a flexible printed circuit (FPC). The substrate 20 includes opposing insulating layers 21 and 22 and a wiring pattern 23 formed between the insulating layers 21 and 22. From another perspective, the wiring pattern 23 is formed on the insulating layer 21 and covered with the insulating layer 22.

The insulating layers 21 and 22 are formed of a plastic film such as a polyimide film. In the following description, the insulating layer 21 may be called the "base film 21" and the insulating layer 22 may be called the "cover film 22." Note that the insulating layers 21 and 22 may not be made of the same material. For example, the insulating layer 21 may be formed of a plastic film, while the insulating layer 22 may be formed of a solder resist film.

The wiring pattern 23 is made of copper foil or other conductive metal. The wiring pattern 23 includes a power supply pattern 24 as a first wiring pattern and a ground pattern 25 as a second wiring pattern. Furthermore, the power supply pattern 24 includes a plurality of straight parts and bent parts including a first straight part 24a and a second straight part 24b. Similarly, the ground pattern 25 includes a plurality of straight parts and bent parts, including a first straight part 25a and a second straight part 25b.

In addition, in the following description, the first straight part 24a of the power supply pattern 24 will be abbreviated as "straight part 24a", and the second straight part 24b will be abbreviated as "straight part 24b". Further, the first straight portion 25a of the ground pattern 25 is abbreviated as a “straight portion 25a”, and the second straight portion 25b is abbreviated as a “straight portion 25b”.

The straight line portion 24a of the power supply pattern 24 and the straight line portion 25a of the ground pattern 25 are parallel to each other. Further, the straight portion 24b of the power supply pattern 24 and the straight portion 25b of the ground pattern 25 are parallel to each other. However, the orientation of the straight portions 24a, 25a and the orientation of the straight portions 24b, 25b differ by 90 degrees. From another perspective, the straight portions 24a, 25a and the straight portions 24b, 25b extend in the intersecting direction. More specifically, the straight portions 24a, 25a and the straight portions 24b, 25b extend in orthogonal directions.

The power supply pattern 24 and the ground pattern 25 are electrically connected to the coil 30 to form an electric circuit including the coil 30. The connection state between the wiring pattern 23 and the coil 30 will be explained later.

The base film 21 and the cover film 22 include a rectangular or substantially rectangular main body 26 and a tongue 27 protruding from one side of the main body 26. Further, the tongue portion 27 of the cover film 22 includes a root portion 27a that is connected to the main body portion 26, and a tip portion 27b that is separated from the main body portion 26 and the root portion 27a.

The main body portion 26 of the cover film 22 is provided with openings 28a and 28b. Each of the openings 28a and 28b is a circular through hole formed at a predetermined position in the cover film 22 (main body portion 26).

More specifically, the opening 28a is a through hole formed at a position overlapping the straight portion 24a of the power supply pattern 24. Further, the opening 28b is a through hole formed at a position overlapping with the linear portion 25a of the ground pattern 25. As a result, a portion of the straight portion 24a of the power supply pattern 24 is exposed through the opening 28a. Further, a portion of the straight portion 25a of the ground pattern 25 is exposed through the opening 28b.

As described above, the tongue portion 27 of the cover film 22 is composed of the root portion 27a and the tip portion 27b which are separated from each other. From another perspective, there is a gap 29 in the tongue 27 of the cover film 22. As a result, a portion of the linear portion 24b of the power supply pattern 24 and the linear portion 25b of the ground pattern 25 are exposed through the gap 29 in the tongue portion 27, respectively.

The exposed portions of the wiring pattern 23 (power supply pattern 24, ground pattern 25) provided as described above form a plurality of connection portions to which the coil 30 is connected. Further, the exposed portion of the wiring pattern 23 forms a terminal portion to be connected to a power supply circuit. From another perspective, the exposed portion of the wiring pattern 23 is used as a connection pad or a connection terminal. The connection portion and terminal portion will be explained later.

<Coil>
5A is an exploded perspective view of the coil 30, and FIG. 5B is a plan view of the coil 30. FIG. 6 is a perspective view showing how the wiring pattern 23 and the coil 30 are connected. Further, FIG. 7 is a plan view showing a connection state between the wiring pattern 23 and the coil 30.

The coil 30 is provided on the substrate 20 and is electrically connected to the wiring pattern 23 provided on the substrate 20. More specifically, the coil 30 is mounted on the cover film 22 of the substrate 20 and is electrically connected to the power supply pattern 24 and the ground pattern 25.

The coil 30 is an air-core coil (coreless coil) without an iron core. More specifically, the coil 30 includes an inner coil 31 provided around a virtual iron core and an outer coil 32 provided around the inner coil 31. From another perspective, the coil 30 includes a primary coil 31 and a secondary coil 32 provided around the primary coil 31. In other words, the coil 30 has a double structure.

The inner coil 31 is formed by a first winding 33 wound a predetermined number of times. The outer coil 32 is formed by a second winding 34 wound a predetermined number of times on the outer peripheral surface of the inner coil 31. From another perspective, the outer peripheral surface of the inner coil 31 and the inner peripheral surface of the outer coil 32 are substantially in contact with each other. From another perspective, there is no gap or space between the inner coil 31 and the outer coil 32 in which a connection pad or a connection terminal can be provided. In this way, not providing an effective space between the inner coil 31 and the outer coil 32 contributes to miniaturization of the coil 30 and, in turn, contributes to miniaturization of the vibration motor 1.

A winding start end 33a and a winding end end 33b of the first winding 33 are drawn out parallel to each other inside the coil 30. More specifically, the winding start end 33a and the winding end end 33b are drawn out inside the inner coil 31 in parallel to each other.

A winding start end 34a and a winding end end 34b of the second winding 34 are drawn out parallel to each other inside the coil 30. More specifically, the winding start end 34a and the winding end end 34b are drawn out parallel to each other across the inner coil 31 and inside the inner coil 31. From another perspective, the winding start end 34a and the winding end end 34b pass between the substrate 20 (cover film 22) and the inner coil 31 and are drawn out to the inside of the inner coil 31.

That is, all ends of the windings forming the coil 30 are drawn out inside the coil 30. Further, the winding start end 33a of the first winding 33 and the winding start end 34a of the second winding 34 are parallel to each other and adjacent to each other. Similarly, the winding end 33b of the first winding 33 and the winding end 34b of the second winding 34 are parallel to each other and adjacent to each other.

However, the winding start ends 33a, 34a and the winding end ends 33b, 34b are drawn out toward the inside of the coil 30 in opposite directions. More specifically, the winding start ends 33a and 34a shown in FIG. 5B are pulled out from the right side to the left side in the paper, while the winding end parts 33b and 34b are pulled out from the left side to the right side in the paper plane. It's being pulled out.

<Connection part>
As described above, a plurality of connection portions are formed on the substrate 20 by the exposed portions of the wiring pattern 23. Specifically, one connection portion 61 is formed inside the coil 30 by a portion of the wiring pattern 23 exposed from the opening 28 a of the cover film 22 . Furthermore, another connection portion 62 is formed inside the coil 30 by a portion of the wiring pattern 23 exposed from the opening 28b of the cover film 22. The connection parts 61 and 62 will be explained in more detail below.

The power supply pattern 24 crosses the inner coil 31 and the outer coil 32 and extends inside and outside the coil 30 . More specifically, the straight portion 24a of the power supply pattern 24 extends in and out of the coil 30 across the inner coil 31 and the outer coil 32. A connecting portion 61 is provided on one side of the straight portion 24a located inside the coil 30. From another perspective, the connecting portion 61 is a part of the straight portion 24a exposed from the opening 28a provided inside the coil 30.

The ground pattern 25 also traverses the inner and outer coils 31 and 32, extending inside and outside the coil 30. More specifically, the straight portion 25a of the ground pattern 25 extends inside and outside the coil 30 across the inner coil 31 and the outer coil 32. A connecting portion 62 is provided on one side of the straight portion 25a located inside the coil 30. From another perspective, the connecting portion 62 is a part of the straight portion 25a exposed from the opening 28b provided inside the coil 30.

The winding start end 33a of the first winding 33 is connected to the connection part 61, and the winding start end 34a of the second winding 34 is also connected to the connection part 61. Further, the end winding end 33b of the first winding 33 is connected to the connection part 62, and the end winding end 34b of the second winding 34 is also connected to the connection part 62. From another perspective, the winding start ends 33a, 34a are connected to a common connection part 61. Further, the winding end portions 33b and 34b are connected to a common connection portion 62.

That is, both the inner coil 31 and the outer coil 32 are connected to the wiring pattern 23 inside the coil 30. More specifically, the winding start end 33a of the first winding 33 and the winding start end 34a of the second winding 34 are connected to the power supply pattern 24 inside the coil 30. Further, a winding end 33 b of the first winding 33 and a winding end 34 b of the second winding 34 are connected to the ground pattern 25 inside the coil 30 .

From another perspective, one end of the inner coil 31 and the outer coil 32 is connected to the common power supply pattern 24, and the other end of the inner coil 31 and the outer coil 32 is connected to the common ground pattern 25. As a result, the inner coil 31 and the outer coil 32 are connected in parallel.

The coil 30 consisting of two coils (inner coil 31, outer coil 32) connected in parallel has lower electrical resistance than a single coil with the same number of turns. In other words, with the coil 30, sufficient thrust (Lorentz force) can be obtained with low voltage. From another perspective, by using the coil 30, it is possible to achieve high efficiency of the vibration motor 1. Furthermore, the coil 30 of this embodiment has a double structure. Specifically, an outer coil 32 is provided around the inner coil 31. As a result, the coil 30 can be installed in a smaller space than coils of other structures (for example, a structure in which two coils are arranged side by side or a structure in which two coils are arranged one above the other). That is, by using the double-structured coil 30, the vibration motor 1 can be made smaller.

Further, both the inner coil 31 and the outer coil 32 are connected to the wiring pattern 23 inside the coil 30. Therefore, even if the space outside (around) the coil 30 is narrow, both the inner coil 31 and the outer coil 32 can be connected to the wiring pattern 23.

<Terminal part>
As described above, a plurality of terminal portions are formed on the substrate 20 by the exposed portions of the wiring pattern 23. Specifically, the terminal portion 65 is formed by a portion of the power pattern 24 exposed from the gap 29 provided in the tongue portion 27 of the cover film 22 . Furthermore, a terminal portion 66 is formed by a portion of the ground pattern 25 exposed from the gap 29 provided in the tongue portion 27 of the cover film 22. The terminal portions 65 and 66 are connected to a power supply circuit (not shown). As a result, the coil 30 is electrically connected to the power supply circuit via the wiring pattern 23. In other words, a parallel circuit is formed in which the inner coil 31 and the outer coil 32 are each connected to a power supply circuit.

<Modified example>
In the embodiment described above, the straight portion 24a of the power supply pattern 24 and the straight portion 25a of the ground pattern 25 are parallel to each other. Further, the straight portion 24b of the power supply pattern 24 and the straight portion 25b of the ground pattern 25 are parallel to each other. Further, the straight portions 24a, 25a and the straight portions 24b, 25b extend in orthogonal directions.

However, the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit thereof. For example, the arrangement, shape, etc. of the wiring pattern 23 can be changed as appropriate as long as it is possible to realize a wiring state in which both the inner coil 31 and the outer coil 32 are connected to the wiring pattern 23 inside the coil 30. Further, the direction, length, positional relationship, connection destination, etc. of the winding start ends 33a, 34a and the winding end ends 33b, 34b can be changed as appropriate.

8 and 9 are plan views showing different modifications of the wiring pattern 23. FIG. Also in the wiring pattern 23 shown in FIG. 8, the straight part 24a and the straight part 25a are parallel, and the straight part 24b and the straight part 25b are parallel.

However, although the straight portions 24a, 25a and the straight portions 24b, 25b extend in the intersecting direction, they do not extend in the orthogonal direction. From another perspective, the straight portions 24a, 25a and the straight portions 24b, 25b extend in diagonal directions.

Also in the wiring pattern 23 shown in FIG. 9, the straight portions 24a, 25a and the straight portions 24b, 25b extend in diagonal directions. Furthermore, in the wiring pattern 23 shown in FIG. 9, the straight portions 24a and 25a are non-parallel. That is, the straight portions 24a and 25a shown in FIG. 9 extend in directions oblique to the straight portions 24b and 25b, and extend in directions oblique to each other.

In the above embodiments and modifications, the winding start end 33a and the winding start end 34a are pulled out in the same direction from the same or substantially the same position. Further, the winding end portions 33b and 34b were pulled out in the same direction from the same or substantially the same position.

However, an embodiment in which the winding start end 33a and the winding start end 34a are pulled out from different positions, and an embodiment in which the winding end part 33b and the winding end end 34b are pulled out from different positions also apply to the present invention. Included in the embodiments of the invention.

In addition, there are embodiments in which the winding start end 33a and the winding start end 34a are separated or non-parallel, and the winding end 33b and the winding end 34b are separated or non-parallel. Embodiments are also included in the embodiments of the present invention.

Furthermore, an embodiment in which the winding start ends 33a, 34a and the winding end ends 33b, 34b are pulled out in the same direction is also included in the embodiments of the present invention.

DESCRIPTION OF SYMBOLS 1... Vibration motor, 10... Housing, 11... Cover, 12... Base plate, 13... Front part, 14... Back part, 15... Top part, 16... Bottom part, 17... Right side part, 18... Left side part, 20... Substrate, 21... Insulating layer (base film), 22... Insulating layer (cover film), 23... Wiring pattern, 24... Power supply pattern, 24a, 25a... First straight line part (straight line part), 24b, 25b... Second straight line part (straight line part), 25... ground pattern, 26... main body part, 27... tongue part, 27a... root part, 27b... tip part, 28a, 28b... opening part, 29... gap, 30... coil, 31... inner coil , 32... Outer coil, 33... First winding, 34... Second winding, 33a, 34a... Winding start end, 33b, 34b... Winding end end, 40... Vibrating body, 41... Weight, 42... Back Yoke, 43... Permanent magnet, 44... Magnet accommodating part, 50... Elastic member, 51... First fixing part (base end part), 52... Second fixing part (tip part), 53... Central part, 61, 62... Connection part, 65, 66...Terminal part

Claims (7)

a vibrating body containing a permanent magnet;
A board on which a wiring pattern is formed,
a coil provided on the substrate and electrically connected to the wiring pattern formed on the substrate;
The coil includes an inner coil and an outer coil provided around the inner coil,
The wiring pattern includes a first wiring pattern and a second wiring pattern that cross the inner coil and the outer coil and straddle the inside and outside of the coil,
A winding start end of a first winding forming the inner coil and a winding start end of a second winding forming the outer coil are connected to the first wiring pattern inside the coil. ,
The winding end of the first winding forming the inner coil and the winding end of the second winding forming the outer coil are connected to the second wiring pattern inside the coil. Connected, vibration motor. The winding start ends of the first winding and the second winding are parallel to and adjacent to each other,
The vibration motor according to claim 1, wherein the winding end portions of the first winding and the second winding are parallel to and adjacent to each other. The winding start ends of the first winding and the second winding and the winding end ends of the first winding and the second winding are opposite to each other toward the inside of the coil. The vibration motor according to claim 1 or 2, which is pulled out. The first wiring pattern and the second wiring pattern each include a first straight portion extending in and out of the coil across the inner coil and the outer coil,
The winding start ends of the first winding and the second winding are connected to the first straight portion of the first wiring pattern inside the coil,
The winding end portions of the first winding and the second winding are connected to the first straight portion of the second wiring pattern inside the coil. The vibration motor described in section. The winding start ends of the first winding and the second winding are connected to a common connection part provided in the first straight part of the first wiring pattern,
The winding end portions of the first winding and the second winding are connected to a common connection portion provided in the first straight portion of the second wiring pattern,
5. The vibration motor according to claim 4, wherein each of the connecting portions is a part of the first linear portion exposed from an opening provided in an insulating layer covering the wiring pattern. The vibration motor according to claim 4 or 5, wherein the first wiring pattern and the second wiring pattern further include a second straight part extending in a direction intersecting the respective first straight parts. 7. The vibration motor according to claim 6, wherein a terminal portion connected to a power supply circuit is formed by a portion of the second linear portion exposed from a gap in an insulating layer covering the wiring pattern.

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