JP2001102217A - Coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and thin high performance inductor. SOLUTION: An insulation substrate 11 has a through hole 15 and a coil 13 mounted on each side of the substrate 11 has a spiral pattern around the through hole 15. A first core member 3 comprises a bottom plate 21 and an intermediate leg 23. The bottom plate 21 has one side facing the insulation substrate 11 and the intermediate leg 23 stands on one side of the bottom plate 21 to extend through the though hole 15 of the substrate 11. A second core member 5 is made of a magnetic material having electric resistance higher than that of the first core member 3 and disposed on the opposite side to the first core member 3 with respect to a flat coil plate 1 facing the forward end face of the intermediate leg 23. Terminal conductors 7, 9 are disposed on the second core member 5 side and connected, at the ends thereof, with the ends 17, 19 of the coil 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coil device such as a transformer or a choke coil. More specifically,
The present invention relates to a coil device in which a coil is combined with a planar coil plate having a conductor pattern and a core.

[0002]

2. Description of the Related Art In recent years, with the spread of small portable devices such as portable telephones and mobile computers, further reductions in the size and thickness of planar coil plates mounted on these devices have been required. A coil device combining a planar coil plate and a core is suitable for responding to miniaturization and thinning. The planar coil plate is obtained by applying a photolithography process, a plating process, etc., and forming a highly accurate conductor coil pattern on the surface of the insulating substrate, and combining this planar coil plate with a ferrite core. , A transformer or a coil device such as a choke coil. A metal terminal conductor for external connection is attached to the flat coil plate.

In order to obtain excellent characteristics as a coil device, a core is made of a ferrite magnetic material having excellent magnetic characteristics,
For example, it is preferable to use a MnZn-based ferrite magnetic material.

However, ferrite magnetic materials having excellent magnetic properties, for example, MnZn-based ferrite magnetic materials have low electric resistance values.

For this reason, in a structure that has been made smaller and thinner, a pair of metal terminal conductors for external connection and MnZ
When a core made of n-based ferrite magnetic material comes into contact,
The pair of metal terminal conductors are electrically short-circuited to each other by the core made of a MnZn-based ferrite magnetic material having low electric resistance. In order to avoid such a short-circuit phenomenon, a sufficient electric insulation distance must be secured between the metal terminal conductor and the core. This contradicts the demand for miniaturization and thinning.

When a ferrite magnetic material having a higher electric resistance value, typically a NiZn ferrite magnetic material, is used instead of a core made of a MnZn-based ferrite magnetic material, the magnetic characteristics are sacrificed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-performance coil device which is small, thin, and has excellent magnetic properties.

[0008]

In order to solve the above-mentioned problems, a coil device according to the present invention includes at least one planar coil plate, a core, and at least two terminal conductors. The planar coil plate includes at least one insulating substrate and at least one coil. The insulating substrate is flat and has a through hole penetrating in the thickness direction. The coil is provided on at least one surface of the insulating substrate and has a spiral pattern that turns around the through hole.

[0009] The core includes a first core member and a second core member. The first core member is made of a magnetic material having better magnetic properties than the second core member, and includes a bottom plate portion and a middle leg portion, the bottom plate portion having one surface facing the insulating substrate, The middle leg portion is provided upright on the one surface of the bottom plate portion and is disposed to penetrate the through hole of the insulating substrate.

[0010] The second core member is made of a magnetic material having a higher electric resistance than the first core member, and is opposite to the first coil member with the plane coil plate interposed therebetween. And is opposed to the distal end surface of the middle leg portion.

[0011] Each of the terminal conductors is arranged on the second core member side, and an end is connected to an end of the coil.

According to the above structure, the magnetic flux generated when a current flows through the coil is concentrated from the first core member and the second core member to the middle leg portion penetrating the through hole of the insulating substrate. In the present invention, the first core member is provided in the second core member.
, And in particular, a magnetic material having a high saturation magnetic flux density Bs. Therefore,
The middle leg part, which is a part thereof, also has higher magnetic properties than the second core member. For this reason, the middle leg is
As compared with the case where the core member is made of the same magnetic material as the core member, excellent magnetic characteristics can be obtained.

The second core member has lower magnetic characteristics than the first core member, but the middle leg which greatly affects the magnetic characteristics is formed as a part of the first core member. The second core member is disposed so as to face the distal end surface of the middle leg, and does not constitute the middle leg. Therefore, even when a material having low magnetic properties is used as the second core member, deterioration of the magnetic properties as a whole can be almost ignored.

Each of the at least two terminal conductors has an end connected to an end of the coil. Therefore, the coil can be conducted to the external circuit via the terminal conductor.

[0015] Each of the terminal conductors is arranged on the second core member side. The second core member is made of a magnetic material having a higher electric resistance than the first core member. For this reason,
Due to the reduction in thickness and size, even when the terminal conductor and the second core member come into contact with each other, a short circuit between the pair of terminal conductors due to the second core member can be substantially ignored.
This means that further reduction in size and thickness can be achieved.

Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. The accompanying drawings are merely illustrative.

[0017]

1 is a front view of a coil device according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a sectional view taken along line 3-3 of FIG. FIG. 4 is a sectional view taken along line 4-4 in FIG. These figures show examples in which the present invention is applied to a choke coil or the like.

The illustrated coil device has a flat coil plate 1.
, Cores 3 and 5, and a pair of terminal conductors 7 and 9. The plane coil plate 1 includes an insulating substrate 11 and a coil 13. The insulating substrate 11 has a flat plate shape and has a through-hole 15 penetrating in the thickness direction. The coil 13 is connected to the insulating substrate 11
And has a spiral pattern that turns around the through hole 15. Outer coil end 17 of coil 13
Are provided at the corners of the insulating substrate 11, and the inner coil ends 37
Is led out to the other surface of the insulating substrate 11 via the through conductor 43. The conductor pattern 19 is provided on the insulating substrate 11. The conductor pattern 19 is provided at a corner that has a diagonal relationship with a corner having the outer coil end 17.

On the other side of the insulating substrate 11, a conductor pattern 39 is provided. A through conductor 43 connected to the inner coil end 37 is connected to one end of the conductor pattern 39. Also, at the other end of the conductor pattern 39,
Terminal conductor 9 is connected. The terminal conductor 9 is provided to penetrate from one surface side of the insulating substrate 11 to the other surface side.

The cores 3 and 5 are composed of a first core member 3 and a second core member 3.
Core member 5. The first core member 3 includes the bottom plate 2
1 and a middle leg 23. One surface of the bottom plate portion 21 faces the insulating substrate 11, and the middle leg portion 23 is erected on one surface of the bottom plate portion 21 and penetrates through the through hole 15 of the insulating substrate 11. The first core member 3 shown in the embodiment has an E-shaped cross section including two outer legs 25 and 27 on both sides of the middle leg 23.

The second core member 5 is made of a magnetic material having an electric resistance higher than that of the first core member 3, and is located on the opposite side of the plane coil plate 1 from the first core member 3. It is arranged so as to face the distal end surface of the middle leg 23. The illustrated second core member 5 is plate-shaped and has an I-shaped cross section. In the embodiment, since the first core member 3 is an E-shaped core member including the middle leg portion 23 and the outer leg portions 25 and 27, the second core member 5 has one surface on the middle leg portion 23 and the outer leg portion. The parts 25 and 27 are in surface contact.

Each of the terminal conductors 7 and 9 is arranged on the second core member 5 side, the end of the terminal conductor 7 is connected to the outer coil end 17 of the coil 13, and the end of the terminal conductor 9 is connected to the conductor. It is connected to the pattern 19. The terminal conductors 7 and 9 are obtained by forming a metal plate material. The terminal conductors 7 and 9 are arranged on the side of the second core member 5 with gaps g1 and g2 therebetween.

In the coil device having the above structure, the coil 1
The magnetic flux generated when an electric current flows through the first core member 3 and the second core member 5 passes through the through hole 1 of the insulating substrate 11.
5 is concentrated on the middle leg 23. First core member 3
Is made of a magnetic material having a higher saturation magnetic flux density Bs than that of the second core member 5, so that the middle leg 23
Also has a higher saturation magnetic flux density Bs than the second core member 5. For this reason, compared with the case where the middle leg portion 23 is made of the same magnetic material as the second core member 5,
Excellent magnetic properties can be obtained.

Although the second core member 5 has a lower saturation magnetic flux density Bs than the first core member 3, the middle leg portion 23, which has a large effect on magnetic characteristics, is formed by a part of the first core member 3. The second core member 5 includes a middle leg 23
And does not constitute the middle leg 23. Therefore, as the second core member 5, the saturation magnetic flux density B
Even when a material having a low s is used, the deterioration of the magnetic characteristics is small.

The outer leg portions 25 and 27 are connected to the saturation magnetic flux density B
When made of a material with a high s, the cross-sectional area can be reduced,
The overall size can be reduced.

One end of the terminal conductor 7 is connected to the outer coil end 17 of the coil 13 and the other end is a free end. One end of the terminal conductor 9 is connected to the conductor pattern 19 of the coil 13 and the other end is a free end. Therefore, the coil 13 can be electrically connected to the external circuit via the terminal conductors 7 and 9 by using the other end of the terminal conductors 7 and 9 as a connection portion with the external circuit.

The terminal conductors 7 and 9 are arranged on the side of the second core member 5. Specifically, the terminal conductors 7 and 9 are arranged with gaps g <b> 1 and g <b> 2 from the side surface of the second core member 5. As described above, the second core member 5 is made of a magnetic material having a higher electric resistance than the first core member 3. For this reason, the gaps g1 and g2 are reduced due to the reduction in thickness and size, and even when the terminal conductors 7 and 9 and the second core member 5 are short-circuited by soldering or the like during mounting, a short circuit between the terminals does not occur. The short circuit between the pair of terminal conductors 7 and 9 due to the second core member 5 can be substantially ignored. In other words, it is possible to reduce the gaps g1 and g2 so as to reduce the thickness and size of the entire coil device.

Preferably, the first core member 3 is made of MnZ
The second core member 5 is made of an n-based ferrite magnetic material.
It is made of a NiZn ferrite magnetic material. The NiZn-based ferrite magnetic material has, for example, an initial magnetic permeability μ of 800 and a saturation magnetic flux density Bs of 3900 gauss. On the other hand, the MnZn-based ferrite magnetic material has, for example, an initial magnetic permeability μ of 2300 and a saturation magnetic flux density Bs of 5100 gauss. Therefore, the first core member 3 having the middle leg 23
Is made of a MnZn-based ferrite magnetic material, excellent magnetic properties can be obtained.

On the other hand, the MnZn ferrite magnetic material is
For example, while the specific resistance ρ is 0.3Ωm, NiZ
In an n-type ferrite magnetic material, for example, the specific resistance ρ is 10
Ωm or more. Therefore, the second core member 5 is made of NiZn.
By using a ferrite-based magnetic material, the coil 1
Even when the third core member 5 and the second core member 5 come into contact with each other directly or via a bonding material such as solder, a short circuit of the coil 13 due to the second core member 5 can be ignored.

As the magnetic material constituting the first core member 3, a dust core, sendust, or amorphous magnetic material having a high filling rate can be used in addition to the MnZn ferrite magnetic material. Further, as the first core member 5, a drum-shaped member having no outer leg portions 25 and 27 can be used in addition to the E-shaped type shown in the figure. The higher the electrical resistance of the second core member 5 is, the more preferable it is. However, any material having an electrical resistance of 10 kΩ or more can be used.

FIG. 5 is a plan view of a flat coil plate used in the coil device shown in FIGS. 1 to 4, and FIG. 6 is a bottom view of the flat coil plate shown in FIG.

The insulating substrate 11 includes a first side 29, a second side 31, a third side 33, and a fourth side 35, and the first side 29, the third side 33 Are opposed to each other, and the second side 31 and the fourth side 35 are opposed to each other. Insulating substrate 11
Is a first corner C between the first side 29 and the second side 31.
1 and a second corner C2 between the second side 31 and the third side 33, and a third corner between the third side 33 and the fourth side 35. C4, and a fourth corner C4 between the fourth side 35 and the first side 29.

The insulating substrate 11 typically has a square or rectangular planar shape. If it is square or rectangular, after forming a number of coil elements on one wafer used as the insulating substrate 11, the wafer is divided using a dicing saw or the like, and each coil element is used as a planar coil plate. Because it can be taken out, mass production is improved.
In the illustrated embodiment, the insulating substrate 11 has a substantially square shape.

When the insulating substrate 11 is formed in a square or rectangular shape, the first corner C1 and the third corner C3 are located on a diagonal line X, and the second corner C2 and the fourth corner C2 are located on the diagonal line X. Corner C4
Are located on the diagonal Y. Further, although the shape is a square shape or a rectangular shape as a whole, the edge of the corner may be rounded or chamfered.

The insulating substrate 11 is a ceramic, plastic or composite composition, and can be made of a non-magnetic material. Specifically, a glass epoxy resin can be used. Selection of the size and thickness of the insulating substrate 11 is a matter of design. As a practical example,
An example having a thickness of 0.1 mm and a size of 3.5 mm square can be given.

Referring to FIG. 5, the coil 13 is provided on one surface of the insulating substrate 11 in a spiral shape, and includes an inner coil end 37 and an outer coil end 17. The outer coil end 17 is provided at the first corner C1.

Next, referring to FIG. 6, a conductor pattern 39 is provided on the other surface side of the insulating substrate 11. One end of the conductor pattern 39 is connected to the coil 1 by the through conductor 43.
3 and the inner coil end 37. Conductor pattern 39
Is provided at the third corner C3, and is electrically connected to the conductor pattern 19 provided on one surface side of the insulating substrate 11 by the through conductor 45.

The thickness, width, and number of turns of the coil 13 belong to design matters. As a practical example, for example, the insulating substrate 11
Is 3.5 mm square, the coil thickness 120
μm, a width of 80 μm, and a number of turns of 17.5 turns.

In the planar coil plate shown in FIGS.
The outer coil end 17 of the coil 13 is provided at the first corner C1. According to this structure, when the space between the outermost peripheral edge of the coil 13 having the spiral pattern and the four sides of the insulating substrate 11 is taken into consideration, the corner having the largest area is used to make the outer side. The coil end 17 can be formed. For this reason, in forming the outer coil end portion 17, the plane area of the insulating substrate 11 is maximally utilized, and the overall shape can be reduced in size.

Moreover, the conductor pattern 19 is provided at a third corner C3 diagonally opposite to the first corner C1 at which the outer coil end 17 is located. The third corner C3 is provided diagonally to the first corner C1 where the conductor pattern 49 is located. For this reason, even when forming the conductor patterns 19 and 39,
The overall shape can be reduced by maximizing the use of the plane area of the insulating substrate 11.

The coil 13 is typically made of a conductor pattern. Since such a conductor pattern can be formed by applying a photolithography process and a plating technique,
A high-performance flat coil plate having a high-precision pattern can be manufactured with high productivity.

In the illustrated embodiment, the insulating substrate 11 has a conductor pattern 19 at a third corner C3 on one surface on which the coil 13 is formed, and a conductor pattern 19 at a position of the first corner C1 on the other surface. 49. The outer coil end 17 is connected to the insulating substrate 1.
The conductor pattern 49 is electrically connected to the conductor pattern 49 by the through conductor 51 penetrating through the first conductor 1. The other end of the conductor pattern 39 is connected to the conductor pattern 19 by a through conductor 45 penetrating the insulating substrate 11.
Is conducted.

The terminal conductor 7 (see FIGS. 1 and 4) is connected to the outer coil end 17 and the conductor pattern 49 on both surfaces of the insulating substrate 11 by, for example, soldering or other means. The terminal conductor 9 (see FIGS. 1 and 4) is
On both sides, the conductor pattern 19 and the conductor pattern 39 are connected to each other by, for example, soldering or other means. The through conductors 43, 45, and 51 are
For example, when a minute hole of, for example, about 0.2 mm is formed in the wafer constituting the above, and the coil 13 is formed by plating, it can be formed by growing plating in the minute hole.

In the assembled state shown in FIGS. 1 to 3, the coil 13 having the spiral pattern faces the second core member 5. The second core member 5 is made of a magnetic material having a higher electric resistance value than the first core member 3. For this reason,
Due to the reduction in thickness and size, even when the coil 13 and the second core member 5 come into contact with each other, a short circuit of the coil 13 by the second core member 5 can be substantially ignored.

The surface of the insulating substrate 11 having the conductor patterns 39 and 49 is opposed to the bottom plate 21 of the first core member 3 having a low electric resistance. By interposing, it can be electrically insulated.

FIG. 7 is an enlarged sectional view showing a part of the coil 13. FIG. 7 shows a coil 13 formed by applying a photolithography process and a plating technique. The wiring 55 constituting the coil 13 is formed with a line interval G therebetween. The wiring 55 has a height H1 higher than the line interval G.
And the aspect ratio (H1
/ G) is kept larger than 1. Therefore, while increasing the wiring density, the cross-sectional area of the wiring 55 can be increased, and the electric resistance of the coil can be reduced. Since the aspect ratio and the wiring density are determined by the photolithography process and the plating technique, a high-performance flat coil plate having a high-precision pattern can be manufactured with high productivity. As an example, the line width W1 = 80 μm, the height H1 = 120 μm, and the line interval G =
An example of 20 μm can be given. In this case, the aspect ratio (H1 / G) of the gap portion is 6. Wiring 5
An insulating member may be filled between the lines 5 and 55, and may be covered with an insulating member so that the upper surface of the wiring 55 is hidden.

FIG. 8 is a sectional view showing another embodiment of the coil device according to the present invention, FIG. 9 is a sectional view taken along the line 9-9 in FIG. 8, and FIG. 10 is a sectional view taken along the line 10-10 in FIG. FIG. In the drawings, the same components as those shown in FIGS. 1 to 6 are denoted by the same reference numerals. The embodiment shown in FIGS. 8 to 10 also shows a coil device used for a choke coil or the like, but differs from the embodiment shown in FIGS. 1 to 6 on both surfaces of the insulating substrate 11 constituting the flat coil plate 1. , Coil 13 and coil 57 are provided.

FIG. 11 is a plan view of a flat coil plate used in the coil device shown in FIGS. 8 to 10, and FIG.
FIG. 13 is a bottom view of the flat coil plate shown in FIG.
FIG. 14 is a sectional view taken along line -13, FIG.
It is sectional drawing along the line.

The coil 13 is provided in a spiral shape on one surface of the insulating substrate 11, and includes an inner coil end 37 and an outer coil end 17. The outer coil end 17 is provided at the first corner C1.

The coil 57 is provided in a spiral shape on the other surface of the insulating substrate 11 and includes an inner coil end 39 and an outer coil end 41. The inner coil end 39 is electrically connected to the inner coil end 37 of the coil 13 by the through conductor 43 penetrating the insulating substrate 11. The outer coil end 41 is provided at the third corner C3.

The inner coil end 39 of the coil 57 is electrically connected to the inner coil end 37 of the coil 13 by the through conductor 43. According to this, a planar coil plate in which the coil 13 and the coil 57 are connected in series is obtained.

The coil 13 and the coil 57 are
The direction of the current as viewed from one surface side is the same. Therefore, when a current flows through the coil 13 and the coil 57 connected in series, a magnetic field in the same direction is generated. That is, although the coil 13 and the coil 57 are provided on one surface and the other surface of the insulating substrate 11, respectively, a high-performance flat coil plate that functions as substantially the same coil can be realized.

Further, in the coil 13, the outer coil end 17 is provided at the first corner C1. In the coil 57, the outer coil end 41 is provided at the third corner C3. According to this structure, the corner having the largest area is used when the space between the outermost peripheral edges of the coil 13 and the coil 57 having the spiral pattern and the four sides of the insulating substrate 11 is considered. Thus, the outer coil end 17 and the outer coil end 41 can be formed. Therefore, in forming the outer coil end 17 and the outer coil end 41, the plane area of the insulating substrate 11 can be maximized, and the overall shape can be reduced in size.

Moreover, both the coil 13 and the coil 57 have a spiral pattern, and the outer coil end 41 of the coil 57 is connected to the outer coil end 1 of the coil 13.
7 is located on a third corner diagonally from the first corner C1.
At the corner C3.

In addition, the coil 13 and the coil 57 have the same current direction as viewed from one surface side of the insulating substrate 11 in the structure in which the inner coil end 37 of the coil 13 and the inner coil end 39 of the coil 57 are connected. Therefore, the winding direction of the coil 13 as viewed from one surface of the insulating substrate 11 and the winding direction of the coil 57 as viewed from the other surface of the insulating substrate 11 match. Therefore, for example, when the coil 13 and the coil 57 are formed by a photolithography process or the like,
The same photomask can be used. Therefore, the cost is reduced. In particular, in the case of the embodiment in which the insulating substrate 11 has a square planar shape, the positioning can be performed only by rotating the insulating substrate 11 relative to the photomask used to form the coil 13 by 90 degrees. The photolithography process is simplified. When the same photomask is used, the pattern of the coil 13 viewed on one surface of the insulating substrate 11 and the pattern of the coil 57 viewed on the other surface of the insulating substrate 11 are placed at positions where the coil ends overlap.
And, they are made substantially the same.

Each of the inner coil end 37 of the coil 13 and the inner coil end 39 of the coil 57 has the second corner C
It is provided on a diagonal Y passing through the second and fourth corners C4. When the insulating substrate 11 has a typical planar shape of a square or a rectangle, the inner coil ends 37, 39
Are located on a diagonal Y intersecting with a diagonal X passing in the direction of the corner C1 and the third corner C3. This arrangement is effective for further improving the utilization efficiency of the insulating substrate 11. For example, regarding the coil 13 and the coil 57,
By making the radius of curvature of the coil turn seen on the side of the fourth corner C4 smaller than the radius of curvature of the coil turn seen on the side of the second corner C2 at the diagonal position, the fourth corner C4 is obtained. , The coil 13 and the coil 57 are made to protrude, the utilization efficiency of the insulating substrate 11 is improved, and the size can be reduced.

In the illustrated embodiment, the insulating substrate 11 has the conductor pattern 19 at the third corner C3 on one surface on which the coil 13 is formed, and the first substrate on the other surface on which the second coil 57 is formed. Has a conductor pattern 49 at the corner C1. The outer coil end 17 is electrically connected to the conductor pattern 49 by the through conductor 51. The outer coil end 41 is electrically connected to the conductor pattern 19 by the through conductor 45. Therefore, the outer coil end 17 and the outer coil end 41 can be connected to an external circuit on both surfaces of the insulating substrate 11. That is, since there is no directionality on both sides of the insulating substrate 11, the assembling work becomes easy.

In the assembled state shown in FIGS. 8 to 10, the coil 13 having the spiral pattern is formed by the second core member 5.
Face to face. The second core member 5 is made of a magnetic material having a higher electric resistance value than the first core member 3. Therefore, even when the coil 13 and the second core member 5 come into contact with each other due to the reduction in thickness and size, the second core member 5
The short circuit of the coil 13 due to the above can be substantially ignored.

Also, in the embodiment shown in FIGS.
The terminal conductors 7 and 9 (see FIG. 10) are arranged on the second core member 5 side. As described above, the second core member 5 is made of a magnetic material having a higher electric resistance than the first core member 3. For this reason, by thinning and miniaturization,
Even when the terminal conductors 7, 9 and the second core member 5 come into contact with each other directly or with a bonding material such as solder, short-circuiting of the pair of terminal conductors 7, 9 by the second core member 5 can be prevented. It becomes practically negligible. Therefore, it is possible to reduce the thickness and size of the entire coil device.

In the plane coil plate 1, the surface of the insulating substrate 11 having the coil 57 is opposed to the bottom plate portion 21 of the first core member 3 having low electric resistance. By interposing an insulator, the coil 57 can be electrically insulated from the first core member 3.

FIG. 15 is a front view showing another example of the coil device according to the present invention, and FIG. 16 is a sectional view taken along the line 16-16 in FIG. In the drawings, the same components as those shown in FIGS. 1 to 14 are denoted by the same reference numerals. In this embodiment, the first core member 3 has a T-shaped cross section without an outer leg. Therefore, the overall shape of the combination of the first core member 3 and the second core member 5 having the I-shaped cross section is a so-called drum type. Although not shown, the drum type can be used in the structures shown in FIGS.

FIG. 17 is a front view showing another example of the coil device according to the present invention, FIG. 18 is a sectional view taken along the line 18-18 in FIG. 17, and FIG. 19 is a view taken along the line 19-19 in FIG. It is sectional drawing. In the drawings, the same components as those shown in FIGS. 1 to 16 are denoted by the same reference numerals. In the illustrated coil device, the second core member 5
Has a nonmagnetic film 63 on the surface facing the planar coil plate 1. According to this structure, the effect of improving the DC superimposition characteristic by the nonmagnetic film 63 can be obtained.

The non-magnetic film 63 can be made of a synthetic resin. When a synthetic resin is used as the non-magnetic film 63, the surface of the second core member 5 can be coated with a synthetic resin paint by means such as spin coating, so that the formation of the non-magnetic film 63 is facilitated.

Next, the present invention will be described with reference to examples and comparative examples. <Embodiment 1> In the coil device having the structure shown in FIGS. 17 to 19, the configuration of each part was designed as follows. (1) First core member 3 Constituent magnetic material: MnZn-based ferrite magnetic material Initial magnetic permeability μ: 2300 Saturated magnetic flux density Bs: 5100 gauss Specific resistance ρ: 0.3 Ωm External dimensions: 2.4 × 4.4 × 0 0.9 t (unit: mm) cross section E: middle leg 23: 1.4φ (mm) outer leg 25, 27: 0.4 mm width (2) Second core member 5 Constituent magnetic material: NiZn ferrite magnetic material Initial permeability μ: 800 Saturated magnetic flux density Bs: 3900 gauss Specific resistance ρ: 10 Ωm or more External dimensions: 2.4 × 4.4 × 0.4 t (unit mm) cross section I type (3) Planar coil plate 1 Insulating substrate 11 Constitution material: Glass epoxy board (FR4 grade) Thickness: 0.1 mm Outer shape: 3.5 mm square Coil 13, 57 Line width: 80 μm Height: 120 μm Line spacing: 20 μm

Comparative Example 1 In the coil device having the structure shown in FIGS. 17 to 19, the configuration of each part was designed as follows. (1) First core member 3 Constituent magnetic material: MnZn-based ferrite magnetic material Initial magnetic permeability μ: 2300 Saturated magnetic flux density Bs: 5100 gauss Specific resistance ρ: 0.3 Ωm External dimensions: 2.4 × 4.4 × 0 0.9 t (unit: mm) cross section E: middle leg 23: 1.4φ (mm) outer leg 25, 27: width 0.4 mm (2) Second core member 5 Constituent magnetic material: MnZn ferrite magnetic material Initial permeability μ: 2300 Saturated magnetic flux density Bs: 5100 gauss Specific resistance ρ: 0.3 Ωm or more External dimensions: I-type cross section of 2.4 × 4.4 × 0.4 t (unit: mm) (3) Planar coil plate 1 Insulating substrate 11 Constitution material: Glass epoxy substrate (FR4 grade) Thickness: 0.1 mm External shape: 3.5 mm square Coil 13, 57 Line width: 80 μm Height: 120 μm Line spacing: 20 μm

Comparative Example 2 In the coil device having the structure shown in FIGS. 8 to 10, the configuration of each part was designed as follows. (1) First core member 3 Constituent magnetic material: NiZn-based ferrite magnetic material Initial magnetic permeability μ: 800 Saturated magnetic flux density Bs: 3900 gauss Specific resistance ρ: 10 Ωm or more Dimensions: 2.4 × 4.4 × 0. 9 t (unit: mm) cross section E Middle leg 23: 1.4φ (mm) Outer leg 25, 27: width 0.4 mm (2) Second core member 5 Constituent magnetic material: NiZn ferrite magnetic material Initial Permeability μ: 800 Saturated magnetic flux density Bs: 3900 gauss Specific resistance ρ: 10 Ωm or more External dimensions: 2.4 × 4.4 × 0.4 t (unit mm) cross section I type (3) Planar coil plate 1 Insulating substrate 11 Constituent material: Glass epoxy board (FR4 grade) Thickness: 0.1 mm External form: 3.5 mm square Coil 13, 57 Line width: 80 μm Height: 120 μm Line spacing: 20 μm

Comparative Example 3 The components of the coil device having the structure shown in FIGS. 8 to 10 were designed as follows. (1) First core member 3 Constituent magnetic material: NiZn-based ferrite magnetic material Initial magnetic permeability μ: 800 Saturated magnetic flux density Bs: 3900 gauss Specific resistance ρ: 10 Ωm or more Dimensions: 2.4 × 4.4 × 0. 9 t (unit: mm) cross section E Middle leg 23: 1.4φ (mm) Outer leg 25, 27: width 0.4 mm (2) Second core member 5 Constituent magnetic material: MnZn ferrite magnetic material Initial Permeability μ: 2300 Saturated magnetic flux density Bs: 5100 gauss Specific resistance ρ: 0.3 Ωm External dimensions: 2.4 × 4.4 × 0.4 t (unit mm) cross section I type (3) Planar coil plate 1 Insulating substrate 11 Constitution material: Glass epoxy board (FR4 grade) Thickness: 0.1 mm Outer shape: 3.5 mm square Coil 13, 57 Line width: 80 μm Height: 120 μm Line spacing: 20 μm

FIG. 20 is a diagram showing the coil current-inductance characteristics of Example 1 and Comparative Examples 1 to 3. In the figure, the horizontal axis indicates the coil applied current (A), and the vertical axis indicates the inductance value (μH). Curve L1 is Example 1.
, The curve L2 is the characteristic of the coil device of Comparative Example 1, the curve L3 is the characteristic of Comparative Example 2, and the curve L4 is the characteristic of Comparative Example 3. In the measurement, each coil device was measured under the conditions of a measurement frequency of 500 kHz and a measurement voltage amplitude of 1 V.

In the data of FIG. 20, the characteristic curve L1
And the characteristic curves L2, L3, and L4, the coil device of Example 1 according to the present invention is
Compared with Comparative Example 2, the DC superimposition characteristics in the large current region are slightly deteriorated, and the DC superimposition characteristics are considerably superior to Comparative Examples 2 and 3. Note that Comparative Example 1 is inferior to Example 1 in terms of withstand voltage.

Next, an example in which the present invention is applied to a transformer will be described. 21 is a sectional view showing another embodiment of the coil device according to the present invention, FIG. 22 is a sectional view taken along line 22-22 of FIG. 21, and FIG. 23 is a sectional view taken along line 23-23 of FIG. FIG. 24 is a diagram showing an electric circuit diagram of the coil device shown in FIGS.

In the embodiment shown in FIGS. 21 to 24, the planar coil plate 1 has the coils 81 and 83 on one surface of the insulating substrate 11 and the coils 77 and 79 on the other surface of the insulating substrate 11.
Having. In addition to the terminal conductors 7 and 9,
Terminal conductors 67 and 73 are provided. The terminal conductor 67 is connected to the coil 8 via a through conductor 69 and a conductor pattern 65.
1, 83 are connected to one end. The other ends of the coils 81 and 83 are guided to the terminal conductor 7 via the conductor pattern 17 and the through conductor 51. The terminal conductor 73 is connected to the coils 77, 7 via the through conductor 75 and the conductor pattern 71.
9 is connected to one end. The other ends of the coils 77 and 79 are guided to the terminal conductor 9 via the conductor pattern 19 and the through conductor 45.

The coil 81 is provided in a spiral shape on one surface of the insulating substrate 11, and the coil 83 is provided in a spiral shape on the coil 81 with the interlayer insulating member 12 interposed therebetween. Are not conducted). The coil 77 is provided in a spiral shape on the other surface of the insulating substrate 11. The interlayer insulating member 12 is provided on the coil 77, and the coil 79 is provided on the interlayer insulating member 12 in a spiral shape. The coil 77 and the coil 79 are electrically connected to each other at an inner coil end (not shown). The coils 83 and 79 are formed by filling an insulating member (not shown) between the wires together with the interlayer insulating member 12 to form a plane, and forming the plane on the plane in the same manner as the formation of the coils 81 and 77. It can be formed by means. According to such a configuration, a small and thin four-terminal transformer having a circuit configuration as shown in FIG. 24 can be obtained.

FIG. 25 is a sectional view showing another embodiment of the coil device according to the present invention, FIG. 26 is a sectional view taken along line 26-26 in FIG. 25, and FIG. 27 is a sectional view taken along line 27-27 in FIG. FIG. 28 is a diagram showing an electric circuit diagram of the coil device shown in FIGS.

In the embodiment shown in FIGS. 25 to 28, the planar coil plate 1 has coils 81, 83,
97 and 99 and coils 77 and 79 on the other surface side of the insulating substrate 11. The planar coil plate 1 is provided with terminal conductors 87, 93 in addition to the terminal conductors 7, 9, 67, 69. The terminal conductor 87 is connected to one ends of the coils 97 and 99 via the through conductor 89 and the conductor pattern 85. The other ends of the coils 97 and 99 are guided to a terminal conductor 93 via a conductor pattern 91 and a through conductor 95.

The coil 97 is provided in a spiral shape on one surface of the insulating substrate 11, and the coil 99 is provided in a spiral shape on the coil 97, and both are electrically connected to each other at the end of the inner coil. The coil 81 is provided spirally on the coil 99, and the coil 83 is provided spirally on the coil 81, and both are electrically connected to each other at the inner coil end. The coil 77 is provided in a spiral shape on the other surface of the insulating substrate 11, and the coil 79 is provided in a spiral shape on the coil 77, and both are electrically connected to each other at an inner coil end. The coils are insulated from each other via an interlayer insulating member 12, as in FIGS. According to such a configuration, a small and thin 6-terminal type transformer having a circuit configuration as shown in FIG. 28 can be obtained.

[0076]

As described above, according to the present invention, it is possible to provide a small, thin, high-performance coil device having excellent magnetic properties.

[Brief description of the drawings]

FIG. 1 is a front view of a coil device according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2;

FIG. 5 is a plan view of a flat coil plate used in the coil device shown in FIGS.

6 is a bottom view of the planar coil plate shown in FIG.

FIG. 7 is an enlarged cross section showing a part of the coil.

FIG. 8 is a sectional view showing another embodiment of the coil device according to the present invention.

FIG. 9 is a sectional view taken along line 9-9 in FIG. 8;

FIG. 10 is a sectional view taken along the line 10-10 in FIG. 8;

FIG. 11 is a plan view of a flat coil plate used in the coil device shown in FIGS.

FIG. 12 is a bottom view of the planar coil plate shown in FIG. 11;

FIG. 13 is a sectional view taken along the line 13-13 in FIG. 11;

FIG. 14 is a sectional view taken along the line 14-14 in FIG. 11;

FIG. 15 is a sectional view showing another embodiment of the coil device according to the present invention.

FIG. 16 is a sectional view taken along the line 16-16 in FIG. 15;

FIG. 17 is a front view showing another example of the coil device according to the present invention.

18 is a sectional view taken along the line 18-18 in FIG.

19 is a sectional view taken along line 19-19 in FIG. 17;

FIG. 20 is a diagram showing coil current-inductance characteristics of an example and a comparative example.

FIG. 21 is a plan view showing another embodiment of the coil device according to the present invention.

FIG. 22 is a sectional view taken along the line 22-22 in FIG. 21;

FIG. 23 is a sectional view taken along the line 23-23 in FIG. 21;

FIG. 24 is a diagram showing an electric circuit diagram of the coil device shown in FIGS.

FIG. 25 is a plan view showing another embodiment of the coil device according to the present invention.

26 is a sectional view taken along line 26-26 of FIG.

FIG. 27 is a sectional view taken along the line 27-27 in FIG. 25;

FIG. 28 is a diagram showing an electric circuit diagram of the coil device shown in FIGS.

[Explanation of symbols]

 Reference Signs List 1 plane coil plate 11 insulating substrate 13, 57 coil 3 first core member 5 second core member

Claims (4)

[Claims] 1. A coil device including at least one planar coil plate, a core, and at least two terminal conductors, wherein the planar coil plate includes an insulating substrate and at least one coil, The insulating substrate is a flat plate and has a through hole penetrating in the thickness direction, and the coil is provided on at least one surface of the insulating substrate, and has a spiral pattern that turns around the through hole. The core includes a first core member and a second core member, and the first core member is made of a magnetic material having better magnetic properties than the second core member. , A bottom plate portion, and a middle leg portion, the bottom plate portion has one surface facing the insulating substrate, and the middle leg portion is erected on the one surface of the bottom plate portion and passes through the through hole of the insulating substrate. The second core member is disposed A magnetic material having an electric resistance higher than that of the first core member, disposed on the opposite side to the first core member with the plane coil plate interposed therebetween, and opposed to a tip end surface of the middle leg portion. A coil device in which each of the terminal conductors is disposed on the second core member side, and an end is connected to an end of the coil. 2. The coil device according to claim 1, wherein the first core member is made of a MnZn ferrite magnetic material, and the second core member is made of a NiZn ferrite magnetic material. apparatus. 3. The coil device according to claim 1, wherein the second core member is provided on a surface facing the middle leg.
A coil device having a non-magnetic film constituting a magnetic gap. 4. The coil device according to claim 1, wherein the number of the planar coil plates is at least two, and each of the two planar coil plates has at least one coil. A coil device provided in each of the planar coil plates, wherein the coils are inductively coupled to each other.