Coil component

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a coil component for use in an inductor, a choke coil, an LC filter, a transformer, a balun transformer, and other suitable components, and more particularly, to a coil component having a coil that is formed by removing a portion of a conductor provided on the surface of a core via a laser beam.

2. Description of the Related Art

A coil component disclosed in Japanese Unexamined Patent Application Publication No. 5-41324 will be described as an example of a conventional coil component with reference to FIG.

20

.

In

FIG. 20

, a solenoid coil

100

includes a columnar bobbin

101

made of an insulation magnetic material such as ferrite. A conductor film

102

is located on the surface of the bobbin

101

. A spirally winding groove

103

is formed via a laser beam. The remaining portion of the conductor film

102

defines a coil

104

.

Further, Japanese Unexamined Patent Application Publication No. 5-41324 describes the possibility that at least two pairs of coils can be formed by cutting the conductor film in a similar manner as described above.

In the conventional device having a plurality of coils, there is no specific, efficient method for forming and providing the spiral grooves defining the respective coils and the terminals for connecting the coils.

SUMMARY OF THE INVENTION

Accordingly, to solve the problems described above, preferred embodiments of the present invention provide a coil component having a unique arrangement and method of arranging a plurality of coils and a plurality of terminals connected to the plurality of coils.

According to a preferred embodiment of the present invention, a coil component having a coil formed by removal of a portion of a conductor film provided on a columnar core which includes first and second terminals insulated from each other, provided in the conductor film on one end portion of the core by formation of a first dividing groove and a second dividing groove in the conductor film, third and fourth terminals insulated from each other, provided in the conductor film on the other end portion of the core by formation of a third dividing groove and a fourth dividing groove in the conductor film, a first winding-around groove provided on the conductor film and extending from the first dividing groove to the third or fourth dividing groove continuously with the first and third or fourth dividing grooves, a second winding-around groove provided on the conductor film and extending from the second dividing groove to the fourth or third dividing groove continuously with the second and fourth or third dividing grooves, arranged substantially parallel to the first winding-around groove, and a first coil and a second coil arranged substantially parallel to each other defined by the first and second winding-around grooves.

Other features, elements, characteristics and advantages of the present invention will become more apparent from the detailed description of preferred embodiments thereof with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view of a coil component according to a preferred embodiment of the present invention;

FIG. 2A

is a partially perspective view of the coil component of

FIG. 1

viewed from one end side in the longitudinal direction of the coil component;

FIG. 2B

is a partially perspective view of the coil component of

FIG. 1

viewed from the other end side in the longitudinal direction of the coil component;

FIG. 3

is a cross-sectional view of the coil component of

FIG. 1

taken along a cut line A—A in

FIG. 1

;

FIG. 4

is a developed schematic view of the coil component of

FIG. 1

;

FIG. 5

is a perspective view showing a portion of the coil component according to another preferred embodiment of the present invention;

FIG. 6

is a perspective view showing a portion of the coil component according to still a further preferred embodiment of the present invention;

FIG. 7

is a perspective view showing a coil component according to another preferred embodiment of the present invention;

FIG. 8A

is a partially perspective view of the coil component of

FIG. 7

, viewed from one end in the longitudinal direction of the coil component;

FIG. 8B

is a partially perspective view of the coil component of

FIG. 7

, viewed from the other end in the longitudinal direction of the coil component;

FIG. 9

is a cross-sectional view of the coil component of

FIG. 7

taken along cut line A—A in

FIG. 7

;

FIG. 10

is a developed schematic view of the coil component of

FIG. 7

;

FIG. 11

is an equivalent circuit diagram of the coil component of

FIG. 7

;

FIG. 12A

is a perspective view of a modification example of the coil component of

FIG. 7

;

FIG. 12B

is a perspective view of another modification example of the coil component of

FIG. 7

;

FIG. 13

is a perspective view of a coil component according to a second preferred embodiment of the present invention;

FIG. 14A

is a partially perspective view of the coil component of

FIG. 13

, viewed from one end side in the longitudinal direction thereof;

FIG. 14B

is a partially perspective view of the coil component of

FIG. 13

, viewed from the other end side in the longitudinal direction thereof;

FIG. 15

is a developed schematic view of the coil component of

FIG. 13

;

FIG. 16

is an equivalent circuit diagram of the coil component of

FIG. 13

;

FIG. 17

is a perspective view showing a portion of the core constituting a coil component according to another preferred embodiment of the present invention;

FIG. 18

is a perspective view showing a portion of the core constituting a coil component according to a further preferred embodiment of the present invention;

FIG. 19

is a perspective view showing still a further preferred embodiment of the present invention; and

FIG. 20

is a perspective view of a conventional coil component.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, a coil component according to a first preferred embodiment of the present invention will be described.

In

FIG. 1

, a coil component

1

preferably includes a core

2

preferably made of ferrite, and an outer covering film

21

that covers a portion of the core

2

.

The core

2

preferably has a substantially quadratic prism shape with four side surfaces

2

a,

2

b,

2

c,

and

2

d,

as shown in

FIGS. 2A and 2B

. In one end portion and the other end portion of the core

2

, flanges

3

and

4

are provided and preferably have a substantially-drum shaped configuration protruding in the radial direction of the core

2

. The flange

3

has an end surface

3

a,

four side surfaces

3

b

that are substantially parallel to the respective side surfaces of the core

2

, and four inclined surfaces

3

c

inclined with respect to the radial direction of the core

2

. Similarly, the flange

4

has an end surface

4

a,

four side surfaces

4

b,

and four inclined surfaces

4

c.

In the flange

3

, a first terminal

10

and a second terminal

11

are defined by forming a first dividing groove

7

, a second dividing groove

8

, and a first connecting groove

9

. In the flange

4

, a third terminal

15

and a fourth terminal

16

are defined by forming a third dividing groove

12

, a fourth dividing groove

13

, and a second connecting groove

14

. In the portion of the core

2

sandwiched between the flanges

3

and

4

, a first coil

19

and a second coil

20

are defined by forming a first winding-around groove

17

and a second winding-around groove

18

.

As shown in

FIG. 3

, a coat film

5

made of glass is provided on the surface of the core

2

. Further, a conductor film

6

is provided on the coat film

5

. The coat film

6

includes a first conductor film

6

a

disposed on the entire surface of the core

2

, and a second conductor film

6

b

overlapping the first conductor film

6

a

in the flanges

3

and

4

. In the cross-section of

FIG. 3

, a portion of the first conductor film

6

a

and the entire second conductor film

6

b

are not shown, since they are removed by the respective dividing grooves

7

,

8

,

12

, and

13

, and the first and second winding-around grooves

17

and

18

.

The first conductor film

6

a

preferably includes copper or nickel plating formed by an electroless plating method and copper plating formed thereon by an electroplating method. The two plating-layers are provided as described above to reliably provide a predetermined thickness. Accordingly, if a plating having a predetermined thickness can be formed, it is not necessary to provide two overlapped plating layers. For example, copper plating may be formed so as to have a desired thickness by electroplating once.

The second conductor film

6

b

includes nickel plating formed on the first conductor film

6

a

by electroless plating, and a tin plating formed thereon by electroplating.

A portion of the conductor film

6

is irradiated with a laser beam. The respective grooves are formed by removing the irradiated portion. Hereinafter, the configurations of the respective grooves will be described with reference to

FIGS. 2A and 2B

, and FIG.

4

.

FIG. 4

shows the core

2

developed in order to facilitate the understanding of the configurations. The flanges

3

and

4

are shown assuming that they are on the same plane as the core without the concavities and convexities of the flanges being shown.

In the flange

3

, the first dividing groove

7

and the second dividing groove

8

are formed in the second conductor film

6

b,

elongating on a pair of the opposed side surfaces

3

b

and a pair of the inclined surfaces

3

c.

In the end surface

3

a,

a connecting groove

9

is arranged to connect the first and second dividing grooves

7

and

8

to each other. These grooves divide the second conductor film

6

b

in the flange

3

to define the first terminal

10

and the second terminal

11

that are arranged to be insulated from each other.

Further, in the flange

4

, the third dividing groove

12

and the fourth dividing groove

13

are formed in the second conductor film

6

b,

and extend on a pair of the opposed side surfaces

4

b

and a pair of the inclined surfaces

4

c.

In the end surface

4

a,

the connecting groove

14

connecting the third and fourth dividing grooves

12

and

13

to each other, is formed. With these grooves, the third terminal

15

and the fourth terminal

16

being insulated from each other are defined.

Further, the first winding-around groove

17

and the second winding-around groove

18

arranged substantially parallel to each other are formed in the first conductor film

6

a

on the respective side surfaces of the core

2

. One end of the first winding-around groove

17

is connected to the first dividing groove

7

on the inclined surface

3

c

of the flange

3

, and the other end is connected to the third dividing groove

12

on the inclined surface

4

c

of the flange

4

. Further, one end of the second winding-around groove

18

is connected to the second dividing groove

8

on the inclined surface

3

c

of the flange

3

, and the other end is connected to the fourth dividing groove

13

of the inclined surface

4

c

of the flange

4

.

The width of the respective dividing grooves

7

,

8

,

12

, and

13

is preferably larger than that of the respective winding-around grooves

17

and

18

. For this reason, in the case where the winding-around grooves are formed so as to be continuous with the dividing grooves, the winding-around grooves can be securely connected to the dividing grooves, respectively, even if the irradiation position of the laser beam deviates, provided that the deviation is within a predetermined range.

With the first and second winding-around grooves

17

and

18

, the first coil

19

and the second coil

20

are defined to be substantially parallel to each other. In

FIG. 4

, the first coil

19

is shadowed for easy discrimination of the first and second coils

19

and

20

. The first coil

19

, one end of which is connected to the terminal

10

, is wound around the side surfaces

2

a,

2

d,

2

c,

and

2

b

of the core

2

, and the other end is connected to the third terminal

15

. On the other hand, the second coil

20

, one end of which is connected to the second terminal

11

, is wound around the side surfaces of

2

b,

2

a,

2

d,

and

2

c,

and the other end is connected to the fourth terminal

16

.

By irradiating using a laser beam, the grooves are formed only in the first and second conductor films

6

a

and

6

b,

whereby the coils

19

and

20

are formed. In actual manufacturing processes, the bottoms of the grooves may reach the surface of the coat film

5

or core

2

. If the surface portion of the core is removed by irradiation of a laser beam in this manner, the insulation resistance of the ferrite constituting the core is reduced. However, the reduced insulation resistance is compensated by the insulation resistance of the glass constituting the coat film

5

. Accordingly, a characteristic of the coil component

1

can be set at a desired value.

The portion of the core

2

sandwiched between the flanges

3

and

4

is provided with the outer cover

21

preferably made of resin to protect the coils

19

and

20

. The surface of the outer cover film

21

is on the same plane as that of the second conductor film

6

b

provided on the flanges

3

and

4

. As a whole, the differences in height between the flanges

3

,

4

and the core

2

are eliminated, so that the coil component

1

has a substantially quadratic prism shape.

The coil component

1

is a surface mounting type, and is mounted by use of the side surfaces

3

b

and

4

b

of the flanges

3

and

4

having the first and third dividing grooves

7

and

12

formed therein, respectively, or the side surfaces

3

b

and

4

b

having the second and fourth dividing grooves

8

and

13

formed therein, respectively, as mounting surfaces. Though not specifically shown, if a concavity or convexity for indicating the directivity is formed on one or the other end of the core

2

, that is, on the flange

3

or

4

, formation of the electrodes and the coils, and mounting of the component can be properly performed.

The first to fourth dividing grooves

7

,

8

,

12

, and

13

are further elongated on the inclined surfaces

3

c

and

4

c

of the flanges

3

and

4

, respectively. The boundaries between these dividing grooves and the first and second winding-around grooves

17

and

18

are disposed on the inclined surfaces

3

c

and

4

c,

respectively. Accordingly, each of the first and second coils

19

and

20

are completely covered with the outer covering film

21

from one end thereof to the other end, not exposed to the mounting surface, so as to be protected.

FIG. 5

shows a modification example of the above-described preferred embodiment. In a coil component

1

a

of

FIG. 5

, the connection between the respective terminals and the coils is different from that in the above-described example of preferred embodiments of the present invention. One end of the first coil

19

is connected to the first terminal

10

, and the other end is connected to the fourth terminal

16

. Further, one end of the second coil

20

is connected to the second terminal

11

, and the other end is connected to the third terminal

15

. The other configuration is preferably the same as that of the coil component

1

, and the description of this portion is omitted to avoid repetition.

For mounting of the coil component

1

a

configured as described above, the side surfaces

3

b

and

4

b

of the flanges

3

and

4

having the first and third dividing grooves

7

and

12

formed therein, respectively, or the side surfaces

3

b

and

4

b

having the second and fourth dividing grooves

8

and

13

formed therein, respectively, may be used as mounting surfaces. Further, the side surfaces

3

b

and

4

b

of the flanges

3

and

4

that do not have the first to fourth dividing grooves

7

,

8

,

12

, and

13

formed therein, respectively, may also be used as mounting surfaces.

Further, as shown in

FIG. 6

, the conductor films may be eliminated from the side surfaces

3

a

and

4

a

of the flanges

3

and

4

. That is, the first and second terminals

10

and

11

may be arranged so as not to extend on the end surfaces

3

a

and

4

a,

respectively.

In

FIG. 6

, only the flange

3

is shown. The third and fourth terminals

15

and

16

may be formed similarly to the first and second terminals

10

and

11

.

A further preferred embodiment of the present invention will be described.

In

FIG. 7

, a coil component

51

preferably includes a core

52

made of ferrite, and an outer covering film

521

which covers a part of the core

52

.

The core

52

preferably has a substantially quadratic prism shape with four side surfaces

52

a,

52

b,

52

c,

and

52

d,

as shown in

FIGS. 8A and 8B

. In one end and the other end of the core

52

, flanges

53

and

54

are provided and each having a substantially drum shape protruding in the radial direction of the core

52

. The flange

53

has an end surface

53

a,

a pair of side surfaces

53

b

1

and a pair of side surfaces

53

b

2

arranged substantially parallel to the respective side surfaces of the core

52

, and a pair of inclined surfaces

53

c

1

and a pair of inclined surfaces

53

c

2

which are continuous with the respective side surfaces of the core

52

and inclined with respect to the axial direction of the core

52

. Similarly, the flange

54

has an end surface

54

a,

side surfaces

54

b

1

and

54

b

2

, and inclined surfaces

54

c

1

and

54

c

2

.

In the flange

53

, a first terminal

510

a,

a second terminal

510

b,

and a third terminal

510

c

are formed by providing first dividing grooves

57

a

and

57

b,

and second dividing grooves

58

a

and

58

b,

and first connecting grooves

59

a

and

59

b.

In the flange

54

, a fourth terminal

511

a,

a fifth terminal

511

b,

and a sixth terminal

511

c

are formed by providing third dividing grooves

512

a

and

512

b,

fourth dividing grooves

513

a

and

513

b,

and second connecting grooves

514

a

and

514

b,

respectively. In the portion of the core

52

sandwiched between the flanges

53

and

54

, first to fourth coils

516

to

519

are formed by providing first to fourth winding-around grooves

515

a

to

515

d.

As shown in

FIG. 9

, a coat film

55

made of glass is provided on the surface of the core

52

. Further, a conductor film

56

is disposed on the coat film

55

. The conductor film

56

preferably includes a first conductor film

56

a

disposed on the entire surface of the core

52

, and a second conductor film

56

b

overlapping the first conductor film

56

a

in the flanges

53

and

54

.

The first conductor film

56

a

preferably includes copper or nickel plating formed by an electroless plating method and a copper plating formed thereon by an electroplating method. The two plating-layers are provided as described above to assure a predetermined thickness. Accordingly, if a plating having a predetermined thickness can be formed, it is not necessary to provide two overlapped plating layers. For example, copper plating may be formed so as to have a desired thickness by electroplating.

The second conductor film

56

b

preferably includes nickel plating provided on the first conductor film

56

a

by electroless plating, and tin plating provided thereon by electroplating.

A portion of the conductor film

56

is irradiated with a laser beam. The respective grooves are formed by removing the irradiated portion. Hereinafter, the configurations of the respective grooves will be described with reference to

FIGS. 8A

,

8

B, and FIG.

10

.

FIG. 10

shows the core

52

developed in order to facilitate the understanding of the configurations. Flanges

53

and

54

are shown assuming that they are on the same plane as the core without the concavities and convexities of the flanges

53

and

54

being shown.

In the flange

53

, the first dividing grooves

57

a

and

57

b

and the second dividing grooves

58

a

and

58

b

are formed in the second conductor film

56

b,

extending on a pair of the opposed side surfaces

53

b

1

and a pair of the inclined surfaces

53

c

1

. In the end surface

53

a,

connecting grooves

59

a

and

59

b

are arranged to connect the dividing grooves to each other. With these dividing and connecting grooves, first, second, and third terminals

510

a,

510

b,

and

510

c

which are insulated from each other are provided in the flange

53

.

Further, in the flange

54

, the third dividing grooves

512

a

and

512

b

and the fourth dividing grooves

513

a

and

513

b

are formed in the second conductor film

56

b,

extending on a pair of the opposed side surfaces

54

b

1

and a pair of the inclined surfaces

54

c

1

, respectively. In the end surface

4

a,

the connecting grooves

514

a

and

514

b

connecting the dividing grooves to each other, are formed. With these grooves, fourth, fifth, and sixth terminals

511

a,

511

b,

and

511

c,

which are insulated from each other, are formed in the flange

54

.

Further, first to fourth winding-around grooves

515

a

to

515

d,

winding around the core

52

so as to not cross each other, are formed in the first conductor film

56

a

on the respective side surfaces of the core

52

. The first winding-around groove

515

a

is elongated from the end of the first dividing groove

57

a

on the inclined surface

53

c

1

of the flange

53

onto the side surface

52

a

of the core

52

, and via the point P on the tangential line between the side surface

52

a

and the side surface

52

d

of the core

52

, passed through the side surfaces

52

d,

52

c,

and

52

b,

returned to the side surface

52

a,

and connected to the third dividing groove

512

a

on the inclined surface

54

c

1

of the flange

54

. Further, the second winding-around groove

515

b

is elongated from the end of the first dividing groove

57

b

on the inclined surface

53

c

1

of the flange

53

, passed through the side surface

52

a

of the core

52

, and via the point q, passed through the side surfaces

52

d,

52

c,

and

52

b,

and connected to the third dividing groove

512

b

on the inclined surface

54

c

1

of the flange

54

.

The third winding-around groove

515

c

is elongated from the end of the second dividing groove

58

a

on the inclined surface

53

c

1

of the flange

53

onto the side surface

52

c

of the core

52

, passed through the side surfaces

52

b

and

52

a,

and via the point x on the tangential line between the side surfaces

52

a

and

52

d

of the core

52

, passed through the side surfaces

52

d,

returned to the side surface

52

c,

and connected to the fourth dividing groove

513

a

on the inclined surface

54

c

1

of the flange

54

. The fourth winding-around groove

515

d

is elongated from the end of the second dividing groove

58

b,

passed through the side surfaces

52

c,

52

b,

and

52

a

of the core

52

, and via the point y, connected to the fourth dividing groove

513

b.

The widths of the first to fourth dividing grooves

57

a,

57

b,

58

a,

58

b,

512

a,

512

b,

513

a,

and

513

b

are preferably larger than those of the first to fourth winding-around grooves

515

a

to

515

d,

respectively. For this reason, in the case where the winding-around grooves are formed via a laser beam, the winding-around grooves are securely connected to the dividing grooves, respectively, even if the irradiation position of the laser beam is deviated, provided that the deviation is within a predetermined range.

With the first to fourth winding-around grooves

515

a

to

515

d,

first to fourth coils

516

to

519

are arranged so as not to cross each other. In

FIG. 10

, for easy discrimination of the first to fourth coils

516

to

519

, the respective coils are shadowed. The first coil

516

, one end of which is connected to the first terminal

510

a,

is wound around the core

52

from the side surface

52

d

of the core

52

and through the side surfaces

52

c

and

52

b,

and the other end is connected to the fourth terminal

511

a

on the side surface

52

a.

Further, the second coil

517

, one end of which is connected to the second terminal

510

b,

is wound around the side surfaces

52

c,

52

b,

and

52

a

of the core

52

, and via the side surface

52

d,

returned to the surface

52

c,

and the other end is connected to the fifth terminal

511

b.

Further, the third coil

518

, one end of which is connected to the third terminal

510

c,

is wound around the side surfaces

52

b,

52

a,

52

d,

and

52

c

of the core

52

, and the other end is connected to the sixth terminal

511

c.

Further, the fourth coil

519

, one end of which is connected to the second terminal

510

b,

is wound around the side surfaces

52

a,

52

d,

52

c,

and

52

b

of the core

52

, and returned to the side surface

52

a.

The other end is connected to the fifth terminal

511

b.

Both ends of the second coil

517

and both ends of the fourth coil

519

are connected to each other via the second terminal

510

b

and the fifth terminal

511

b,

respectively, so as to be integrated with each other.

FIG. 11

shows an equivalent circuit for the coil component

51

. In

FIG. 11

, the first to the third coils

516

to

518

define independent coils. The fourth coil

519

is connected in parallel to the second coil

517

.

In the coil component

51

, the first to the fourth coils

516

to

519

are preferably arranged substantially parallel to each other. Accordingly, the coupling degrees between the coils are high, and the distributed capacitances between the coils are equally generated. Thus, a distributed constant type of coil component can be realized.

In the second coil

517

and the fourth coil

519

which are integral with each other, the same current-carrying capacity can be obtained even if the widths of the coils are reduced to half thereof, respectively. Accordingly, the area of the core

52

occupied by the conductor can be decreased. That is, the size of the coil component

51

can be reduced. If the widths of the coils are not changed, twice as much current-carrying capacity can be obtained.

By irradiation of a laser beam, grooves are formed only in the first and second conductor films

56

a

and

56

b,

whereby the first to fourth coils

516

to

519

are defined. In actual manufacturing processes, the bottoms of the grooves may reach the surface of the coat film

55

or core

52

. If the surface portion of the core is removed by irradiation of a laser beam, the insulation resistance of the ferrite constituting the core is reduced. However, the reduced insulation resistance is compensated by the insulation resistance of the glass constituting the coat film

55

. Accordingly, a desired value of a characteristic of the coil component

51

can be accurately achieved.

The portion of the core

52

sandwiched between the flanges

53

and

54

is provided with an outer cover

521

made of resin to protect the first to fourth coils

516

to

519

. The surface of the outer cover film

521

is on the same plane as the surface of the flanges

53

and

54

, that is, that of the second conductor film

56

b

provided on the flanges

53

and

54

. As a whole, the differences in height between the flanges

53

,

54

and the core

52

are eliminated, so that the coil component

51

has a substantially quadratic prism shape.

The coil component

51

is a surface mounting type, and is mounted by use of the side surface

53

b

1

of the flange

53

having the first dividing grooves

57

a

and

57

b

formed therein and also the side surface

54

b

1

of the flange

54

having the third dividing grooves

512

a

and

512

b

formed therein as mounting surfaces. Further, the side surfaces

53

b

1

of the flange

53

having the second dividing grooves

58

a

and

58

b

formed therein, and the side surfaces

54

b

1

of the flange

54

having the fourth dividing grooves

513

a

and

513

b

formed therein may be used as mounting surfaces.

The end surfaces

53

a

and

54

a

of the flanges

53

and

54

have a substantially quadrangle shape, and preferably a rectangle shape. Hence, the electrical directivity can be easily discriminated. When the core

52

is fed to a working machine in the laser working process for forming the respective winding-around grooves, the directivity can be discriminated securely and accurately. In addition, when mounting onto a printed-circuit board, the discrimination of the directivity can be easily performed. Moreover, a concavity or convexity (not shown) may be formed on one or the other end of the core

52

, that is, on the flange

53

or

54

in order to discriminate the electrical directivity.

The first to fourth dividing grooves

57

a,

57

b,

58

a,

58

b,

512

a,

512

b,

513

a,

and

513

b

are further extended on the inclined surfaces

53

c

1

and

54

c

1

of the flanges

53

and

54

, respectively. The boundaries between these dividing grooves and the first to fourth winding-around grooves

515

a

to

515

d

are located on the inclined surfaces

53

c

1

and

54

c

1

, respectively. Accordingly, each of the first to fourth coils

517

to

519

is entirely covered with the outer covering film

521

from one end thereof to the other end without the coils

517

to

519

being exposed to the mounting surface, to be protected.

As shown in

FIG. 12A

, in the flange

53

, the conductor film

56

may be formed only on the side surfaces

53

b

1

and

53

b

2

and the inclined surfaces

53

c

1

and

53

c

2

, the first dividing grooves

57

a

and

57

b

and the second dividing grooves

58

a

and

58

b

are formed, and as shown in

FIG. 12B

, a strip conductor

560

is formed on the end surface

53

a

of the flange

53

by plating or other such processes. Accordingly, a first terminal

510

a

and a third terminal

510

c

which are not extended on the end surface

53

a

of the flange

53

, and also a second terminal

510

b

further extending on the end surface

53

a

of the flange

53

are formed. Fourth to sixth terminals

511

a

to

511

c

provided on the flange

54

may have the same configuration as described above.

Hereinafter, the configuration of a coil component according to a second preferred embodiment of the present invention will be described with reference to

FIGS. 13

,

14

A,

14

B, and

15

. Similar elements in

FIGS. 7

to

10

are designated by similar reference numerals, and description of the similar elements is omitted.

In

FIG. 13

, a coil component

51

a

preferably includes a core

52

, and an outer covering film

52

that covers a portion of the core

52

.

The core

52

preferably has a substantially quadratic prism shape with four side surfaces

52

a,

52

b,

52

c,

and

52

d,

as shown in

FIGS. 14A and 14B

. Flanges

53

and

54

each have a substantially drum shape configuration and are disposed on the core

52

. The flange

53

has an end surface

53

a,

a pair of side surfaces

53

b

1

, a pair of side surfaces

53

b

2

, a pair of inclined surfaces

53

c

1

, and a pair of inclined surfaces

53

c

2

. Similarly, the flange

54

has an end surface

54

a,

a pair of side surfaces

54

b

1

, a pair of side surfaces

54

b

2

, a pair of inclined surfaces

54

c

1

, and a pair of inclined surfaces

54

c

2

.

In the flange

53

, a first terminal

530

a,

a second terminal

530

b,

a third terminal

530

c,

and a fourth terminal

530

d

are formed by providing first dividing grooves

527

a,

527

b,

and

527

c,

second dividing grooves

528

a,

528

b,

and

528

c,

and first connecting grooves

529

a,

529

b,

and

529

c,

respectively. In the flange

54

, a fifth terminal

531

a,

a sixth terminal

531

b,

a seventh terminal

531

c,

and an eighth terminal

531

d

are formed by providing third dividing grooves

532

a,

532

b,

and

532

c,

fourth dividing grooves

533

a,

533

b,

and

533

c,

and second connecting grooves

534

a,

534

b,

and

534

c.

In the portion of the core

52

sandwiched between the flanges

53

and

54

, first to sixth coils

536

to

541

are formed by providing first to sixth winding-around grooves

535

a

to

535

f.

A coat film made of glass is provided on the surface of the core

52

, and a conductor film is formed on the coat film, though not shown. The conductor film preferably includes a first conductor film formed on the entire surface of the core

52

, and a second conductor film overlapping the first conductor film in the flanges

53

and

54

.

A portion of the conductor film is irradiated with a laser beam. The respective grooves are formed by removing the irradiated portion. Hereinafter, the configurations of the respective grooves will be described with reference to

FIGS. 14A and 14B

, and FIG.

15

.

FIG. 15

shows the core

52

developed in order to facilitate the understanding of the configurations. The flanges

53

and

54

are shown assuming that they are on the same plane as the core without the concavities and convexities of the flanges being shown.

In the flange

53

, the first dividing grooves

527

a

to

527

c

and the second dividing grooves

528

a

to

528

c

are formed in the conductor film, extending on a pair of the opposed side surfaces

53

b

1

and a pair of the inclined surfaces

53

c

1

. The connecting grooves

529

a

to

529

c

connecting these dividing grooves to each other are formed in the end surface

53

a.

These grooves and the connecting grooves extending form first to fourth terminals

530

a

to

530

d

insulated from each other in the flange

53

.

Further, in the flange

54

, the third dividing grooves

532

a

to

532

c

and the fourth dividing grooves

533

a

to

533

c

are formed in the conductor film, extending on a pair of the opposed side surfaces

54

b

1

and a pair of the inclined surfaces

54

c

1

. In the end surface

54

a,

the connecting grooves

534

a

to

534

c

connecting these dividing grooves to each other are formed. With these grooves, fifth to eighth terminals

531

a

to

531

d,

which are insulated from each other, are formed in the flange

54

.

Further, in the conductor film on the respective side surfaces of the core

52

, first to sixth winding-around grooves

535

a

to

535

f

are arranged so as to wind around the core

52

and to not cross each other. The first winding-around groove

535

a

is extended from the end of the first dividing groove

527

a

on the inclined surface

53

c

1

of the flange

53

onto the side surface

52

a

of the core

52

, and via the point P on the tangential line between the side surface

52

a

and the side surface

52

d

of the core

52

, passed through the side surfaces

52

d,

52

c,

and

52

b,

and returned to the side surface

52

a,

and connected to the third dividing groove

532

a

on the inclined surface

54

c

1

of the flange

54

. Further, the second winding-around groove

535

b

is extended from the end of the first dividing groove

527

b

on the inclined surface

53

c

1

of the flange

53

, and via the point Q, passed through the side surfaces

52

d,

52

c,

and

52

b,

and connected to the third dividing groove

532

b

on the inclined surface

54

c

1

of the flange

54

. Further, the third winding-around groove

535

c

is extended from the end of the first dividing groove

527

c,

and via the point R, passed through the side surface

52

d,

52

c,

and

52

b,

and connected to the third dividing groove

532

c.

The fourth winding-around groove

535

d

is extended from the end of the second dividing groove

528

a

on the inclined surface

53

c

1

of the flange

53

onto the side surface

52

c

of the core

52

, passed through the side surfaces

52

b

and

52

a,

and via the point X on the tangential line between the side surface

52

a

and the side surface

52

d,

passed through the side surfaces

52

d,

returned to the side surface

52

c,

and connected to the fourth dividing groove

533

a

on the inclined surface

54

c

1

of the flange

54

. The fifth winding-around groove

535

e

is extended from the end of the second dividing groove

528

b,

passed through the side surfaces

52

c,

52

b,

and

52

a

of the core

52

, and via the point Y, connected to the fourth dividing groove

533

b.

The sixth winding-around groove

535

f

is connected via the point Z to the fourth dividing groove

533

c.

With the first to sixth winding-around grooves

535

a

to

535

f,

the first to sixth coils

536

to

541

are arranged so as not to cross each other. In

FIG. 15

, the first to sixth coils

536

to

541

are shadowed for easy discrimination, respectively.

The first coil

536

, one end of which is connected to the first terminal

530

a,

is wound around the side surfaces

52

d,

52

c,

52

b,

and

52

a

of the core

52

, and the other end is connected to the fifth terminal

531

a.

The second coil

537

, one end of which is connected to the second terminal

530

b,

is wound around the side surfaces

52

a,

52

d,

52

c,

and

52

b

of the core

52

, and returned to the side surface

52

a.

The other end is connected to the sixth terminal

531

b.

The third coil

538

, one end of which is connected to the third terminal

530

c,

is wound around the side surfaces

52

a,

52

d,

52

c,

and

52

b

of the core

52

, and returned to the side surface

52

a.

The other end is connected to the seventh terminal

531

c.

The fourth coil

539

, one end of which is connected to the fourth terminal

530

d,

is wound around the side surfaces

52

b,

52

a,

52

d,

and

52

c

of the core

52

, and returned to the side surface

52

b.

The other end is connected to the eighth terminal

531

d.

The fifth coil

540

, one end of which is connected to the second terminal

530

b,

is wound around the side surfaces

52

c,

52

b,

52

a,

and

52

d

of the core

52

, and returned to the side surface

52

c.

The other end is connected to the sixth terminal

531

b.

The sixth coil

541

, one end of which is connected to the third terminal

530

c,

is wound around the side surfaces

52

c,

52

b,

52

a,

and

52

d

of the core

52

, and returned to the side surface

52

c.

The other end is connected to the seventh terminal

531

c.

Both ends of the second coil

537

and both ends of the fifth coil

540

are connected to each other through the second terminal

530

b

and the sixth terminal

531

b,

respectively, so as to be integrated with each other. Both ends of the third coil

538

and both ends of the sixth coil

541

are connected to each other through the third terminal

530

c

and the seventh terminal

531

c

so as to be integrated with each other.

FIG. 16

shows an equivalent circuit of the coil component

51

a.

In

FIG. 16

, the first to the fourth coils

536

to

539

define independent coils. The fifth coil

540

is connected in parallel to the second coil

537

. The sixth coil

541

is connected in parallel to the third coil

538

.

In two sets of the coils arranged integrally as described above, the same current-carrying capacity can be obtained even if the widths of the coils are reduced to half thereof, respectively. Accordingly, the area of the core

52

occupied by the conductor can be decreased. That is, the size of the coil component

51

a

can be reduced. If the widths of the coils are not changed, twice as much current-carrying capacity can be obtained.

The coil component

51

a

has the same advantages as those of the coil component

51

, in addition to the above-described advantages.

In the above-described preferred embodiments, examples are described such that each of the winding-around grooves and the coils formed in the conductor of the core has both ends thereof positioned on the same side surface of the core. However, one end and the other of each of the winding-around grooves and the coils may be formed on the opposite side surfaces.

The shape and size of each flange provided for the core is not restricted to that described in the above preferred embodiments. For example, the flange may have the same shape and size as that of a flange

5301

shown in

FIG. 17

or that of a flange

5302

shown in FIG.

18

.

In the above-described preferred embodiments, the surface of each outer covering film may be positioned near to the center axis of the core, not on the same plane as the surface of the flanges. That is, for example, the outer covering film may be depressed from the surfaces of the flanges, as shown in FIG.

19

.

The material for forming the core may be a magnetic material excluding the ferrite. The core may be formed from glass, a dielectric, plastic, alumina, or other suitable material. In the case where the core is formed from glass or alumina, there is no possibility that the insulation resistance is reduced by the laser beam working, and thereby, it is not necessary to form the coat film on the surface of the core. In this case, the conductor film is formed directly on the surface of the core. The shape of the core is not restricted to a prism. The core may have a column or other shape.

According to preferred embodiments of the present invention, a coil component including a plurality of coils and a plurality of terminals connected to the plurality of coils is provided.

The plurality of coils are arranged so as to be substantially parallel to each other. Accordingly, the coupling degree between the coils is high, and distributed capacitances between the coils are equally generated. Thus, a distributed constant type coil component can be provided.

Preferably, the widths of the dividing grooves on the core are larger those that of each of the winding-around grooves, respectively. For this reason, in the case where the winding-around grooves are formed so as to be connected to the dividing grooves by means of a laser beam, respectively, the winding-around grooves can be securely connected to the dividing grooves, even if the irradiation position of the laser beam is departed, provided that the departure is within a predetermined range.

When the core is formed of a magnetic material or a dielectric material, a coat film made of glass is provided on the surface of the core. Hence, even if the magnetic material or a dielectric is modified by a laser beam applied for formation of the winding-around grooves on the core, and the insulation resistance of the core is reduced, the coat film assures the required insulation resistance. Accordingly, the insulation resistance between a pair of coils can be set at a desired value.

In the coil component of preferred embodiments of the present invention, the end surface of each flange provided for the core may have a substantially quadrangle shape, and preferably a substantially rectangular shape, whereby the electrical directivity can be easily discriminated. In the process of forming the respective winding-around grooves, the directivity can be discriminated securely and accurately when the core is supplied to a working machine. Further, when the coil component is mounted onto a printed circuit board, the discrimination of the directivity can be easily performed.

Preferably, the boundaries between the dividing grooves and the winding-around grooves provided on the core lie on the inclined surfaces of one pair of the flanges protruding from the core. For this reason, when the outer covering is filled into the portion of the core sandwiched between the flanges, coils defined by the winding-around grooves are entirely covered from one end thereof to the other with the outer covering film, and are not exposed to the mounting surface, so as to be protected.

Preferably, the portion of the core sandwiched between the flanges is provided with an outer covering film, and the surface of the outer covering film is on the same plane as the surfaces of the flanges, or is depressed from the surfaces of the flanges toward the approximately center axis of the core. Accordingly, the height of the coil component is minimized.

In the coil component of preferred embodiments of the present invention, different static capacitances can be realized by selecting materials having different dielectric constants for the core or the outer covering film. Thus, the distributed constant of the coil component can be set at a desired value.

It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations which fall within the scope of the appended claims.

Number	Date	Country	Kind
11-232958	Aug 1999	JP
11-349030	Dec 1999	JP

Number	Name	Date	Kind
6087920	Abramov	Jul 2000	A
6087921	Morrison	Jul 2000	A
6094123	Roy	Jul 2000	A
6157283	Tsunemi	Dec 2000	A

Number	Date	Country
888271	Aug 1953	DE
05041324	Feb 1993	JP

Coil component

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (2)

US Referenced Citations (4)

Foreign Referenced Citations (2)