JP2002008922A - Coil part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil part suing a print coil pattern, in which the production cost can be reduce by eliminating the need for making of a through-hole for inserting a leg into a core and the problem of heat generation due to gap be reduced enabling reduction in size. SOLUTION: A print coil pattern 6 of 80-300 μm thickness is formed on the front and on the rear surfaces of an insulation base material 5. First magnetic cores 9, whose thickness is substantially the same or slightly smaller than that of the coil pattern 6, are arranged at the central part on the front and rear surfaces thereof, while the cores are disposed with the insulation base material 5 being pinched. Insulation materials 10 are jointed in a manner such that the material 5 having the coil pattern 6 and cores 9 are covered therewith, thereby forming a substrate 1. Second magnetic cores 2 and 3, forming a magnetic path together with the cores 9, are assembled on the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil component such as a thin transformer and a choke coil used for an electronic device and a power supply device, and more particularly to a transformer and a choke coil for a flyback circuit requiring a core gap.

[0002]

2. Description of the Related Art With the recent miniaturization of electronic equipment, there is a demand for miniaturization and thinning of power transformers and choke coils. In order to meet such demands, various transformers and choke coils in which the winding is formed by a printed coil without using a bobbin have been used.

FIG. 11 is an external view of a conventional transformer of this kind.
FIG. 11A shows the layer structure. This coil component is formed by laminating a plurality of insulating base materials having a spiral coil pattern formed on one or both sides thereof via an insulating layer, and forming a through hole 21 at the center of the laminated substrate 20.
0 is sandwiched between the I-type magnetic core 22 and the E-type magnetic core 23, and the middle leg 24 of the E-type core 23 is inserted into the through hole 21 and assembled. Reference numeral 25 denotes a terminal to be inserted into a through hole 26 provided in the substrate 20.

[0004]

In the above-mentioned conventional coil component, a through hole 21 is provided in a multilayer printed circuit board 20, and a center leg 24 of a magnetic core 23 is fitted into the through hole 21. Therefore, processing of the through hole 21 is required,
In this drilling process, since the size of the through hole 21 is large, a plurality of small holes are concentrically formed by a laser or the like around the position where the through hole 21 is formed, and the through hole 21 is formed as a whole by collecting the small holes. Inevitably, a step of drilling must be adopted, and the hole must be drilled one by one for each coil component, so that the number of processing steps is increased and the cost is increased.

Further, in a coil component such as a transformer, a gap is formed between the middle leg 24 of the E-shaped magnetic core 23 and the I-shaped core 22 so that the cores 22 and 23 are operated in a state where they are hardly saturated. It is configured as follows. However, it is generally known that the leakage magnetic flux generated from the gap generates heat in the coil near the gap. Therefore, in order to reduce this leakage flux, it is necessary to take measures such as separating the coil near the gap from the center leg or not providing a coil around the gap. Hindered.

SUMMARY OF THE INVENTION In view of the above problems, the present invention makes it possible to reduce the cost of a coil component using a printed coil pattern by eliminating the need for machining a through hole for inserting a center leg of a core. It is an object of the present invention to provide a coil component having a configuration in which the problem of heat generation of the coil due to the gap can be reduced and the size can be reduced.

[0007]

According to a first aspect of the present invention, there is provided a coil component, wherein a printed coil pattern having a thickness of 80 to 300 μm is formed on the front and rear surfaces of an insulating base material, and the printed pattern is formed at the center of the coil pattern on the front and rear surfaces. A first magnetic core having a thickness substantially equal to or slightly smaller than the thickness of the coil pattern is disposed with the insulating base material interposed therebetween, and the first magnetic core having the coil pattern and the first magnetic core are joined so as to be covered with an insulating material. To form a substrate, and to form a magnetic path together with the first magnetic core.
Wherein the magnetic core is assembled to the substrate.

According to a second aspect of the present invention, there is provided the coil component, wherein a printed coil pattern is formed on each of the front and back surfaces of the plurality of insulating base materials to a thickness of 80 to 300 μm, and the center of the coil pattern on the front and back surfaces is provided with the coil pattern. A first magnetic core having substantially the same thickness as or slightly thinner than the first magnetic core is disposed with the insulating base material interposed therebetween, and a plurality of coil units having the coil pattern and the first magnetic core are laminated with an insulating material interposed therebetween. , The top layer and the bottom layer are covered with an insulating material to form a substrate,
A second magnetic core forming a magnetic path together with the first magnetic core is assembled to the substrate.

As described in the first and second aspects, the magnetic core is incorporated in a part of the substrate made of the laminated body, so that the processing of the through hole for inserting the middle leg of the magnetic core becomes unnecessary. Since the first magnetic core can be configured as a part of the laminated body, a large number of first magnetic cores can be simultaneously laminated.

[0010] Further, since the first magnetic core is disposed inside the substrate made of the laminated body, the gap between the first magnetic core and the second magnetic core is dispersed, and the heat generation of the coil due to the leakage magnetic flux is greatly reduced. For this reason, it is not necessary to reduce the magnetic flux by increasing the size of the core, or to provide a space between the gap and the coil, thereby enabling downsizing.

According to a third aspect of the present invention, in the coil component, a printed coil pattern having a thickness of 80 to 300 μm is formed on the front and back surfaces of the plurality of insulating bases, and the plurality of insulating bases having the coil pattern are opposed to each other. A third magnetic core having a thickness greater than the total thickness of the coil pattern is laminated with the central portion of the coil pattern interposed therebetween, and on the front and back surfaces of the laminate, the thickness is substantially the same as or slightly smaller than the thickness of the coil pattern. A first magnetic core is disposed at the center of the coil pattern, and a front and back surface of the laminate is covered with an insulating material to form a substrate, and a second magnetic path is formed together with the first and third magnetic cores. A magnetic core is assembled to the substrate.

Thus, at the center of the coil pattern,
By sandwiching the third magnetic core that is thicker than the total thickness of the opposing coil patterns, an insulating material between the coil units becomes unnecessary, and only one third magnetic core between the coil units is required. Further, the interval between the coil patterns can be adjusted by the thickness of the third magnetic core. However, an insulating material between the opposing coil patterns is required.

According to a fourth aspect of the present invention, there is provided a coil component according to the third aspect, wherein an insulating resin for insulating the opposed coil patterns from each other is sealed.

As described above, the structure in which the resin is sealed between the opposing coil patterns makes the insulation process simpler than in the case where an insulating material is applied on the coil patterns.

[0015]

FIG. 1A is a perspective view showing a choke coil (inductor) as an embodiment of a coil component of the present invention, FIG. 1B is an exploded perspective view thereof, and FIG. )
Is a layer structure diagram of the substrate, and FIG. 2B is a sectional view of the coil component.

1A and 1B, reference numeral 1 denotes a substrate having a laminated structure, reference numerals 2 and 3 denote an I-type magnetic core and a C-type magnetic core which are respectively assembled to the substrate 1 from the outside, and 4 denotes a through-hole provided on the substrate 1. This terminal is inserted into and fixed to the hole 1a. 2A and 2B, reference numeral 5 denotes an insulating base made of resin or the like, and reference numeral 6 denotes a spiral coil pattern formed on the front and back surfaces of the insulating base 5, respectively. 6 is connected on its inner peripheral side by a conductor 7 provided in a through hole of the insulating base material 5. The lead portions 6x, 6y of the coil patterns 6, 6 on the front and back surfaces are integrally connected to different positions of a plurality of lands 8 forming terminal insertion through holes formed at the end portions of the front and back surfaces.

Reference numeral 9 denotes a first magnetic core disposed at the center of the coil patterns 6 on the front and back surfaces of the insulating base 5. The thickness of the first magnetic core 9 is substantially the same as or slightly smaller than the thickness of the coil pattern 6. Reference numeral 10 denotes an insulating material which is disposed on the front and back surfaces of the insulating base material 5 so as to cover the coil pattern 6 and the first magnetic core 9 and is joined. As the insulating material 10, an insulating prepreg that can be bonded to the insulating base material 5 by heating and pressure bonding can be used. The insulating material 10 is not a sheet-like material,
Insulating base material 5 provided with coil pattern and first magnetic core 9
An insulating material which forms an insulating layer by coating may be used.

The insulating substrate 5 and coil pattern 6, the first magnetic core 9 and the insulating material 10 of the coil component have elements corresponding to a large number of coil components on the same surface at the same time until the laminating step is completed. It is formed. For example, as described in JP-A-11-204361, the coil pattern 6 is formed by forming a base thin film layer and a resist thereon on an insulating base material 5 made of glass epoxy resin, ceramic, or the like, and forming the resist into a narrow groove. It is possible to use a method of forming a mushroom-shaped coil pattern having a cross-sectional shape larger than the groove width on the groove portion where the resist has been removed and on the vicinity thereof, in the radial direction of the coil pattern 6. Are accurately set and narrowed, and the current capacity is increased by increasing the cross-sectional area of the coil pattern 6.

As the first magnetic core 9, a ferrite molded product or a metal coated with an insulating film is used. These first magnetic cores 9 are set, for example, vertically and horizontally on a surface of a jig in a set portion such as a concave portion, an adhesive is applied to the surface, and a center portion of the coil pattern 6 is placed on the surface. Can be used. Also,
By arranging the first magnetic cores 9 at a constant vertical and horizontal pitch on the insulating material 10 and joining the surface of the first magnetic core 9 to the center of the surface on which the coil pattern 6 is formed, It can be arranged at the center of the coil pattern 6.

The thickness of the insulating substrate 5 is, for example, 60
μm, and the thickness of the coil pattern 6 is 200 μm. In order to make the coil component thin and secure the current capacity, the thickness of the insulating base 5 is 10 μm to 20 μm.
0 μm, thickness of coil pattern 6 is 80 μm to 300 μm
m is preferable. In this example, the first
The thickness of the magnetic core 9 was set to 200 μm similarly to the thickness of the coil pattern 6. The thickness of the first magnetic core 9 may be set to be substantially the same as or slightly smaller than the thickness of the coil pattern 6.

An I-type magnetic core 2 and a C-type magnetic core 3 (hereinafter, referred to as a second magnetic core) are assembled on the substrate 1 having the above-described structure and fixed with an adhesive or a tape.

As described above, with the structure in which the first magnetic core 9 is provided inside the substrate 1, the gap between the first magnetic core 9 and the second magnetic cores 2, 3 is formed by the insulating material 10. It is not necessary to provide a through hole for inserting a core in the substrate 1. Therefore, the number of steps is reduced. Also, the second
Gaps are respectively formed between the magnetic cores 2 and 3 and the first magnetic core 9, and the gaps are dispersedly formed.
Each gap can be reduced, and the heat generation of the coil pattern 6 due to the leakage magnetic flux can be reduced.
Since the coil pattern 6 can be arranged close to the first magnetic core 9, the size can be reduced.

FIG. 3 is a layer structure diagram showing another embodiment of the coil component of the present invention. The present embodiment is configured as a thin transformer, and is provided on the front and back surfaces of the insulating base material 5A.
A coil unit formed with a coil pattern 6A connected by a through-hole conductor on the inner peripheral side, and a coil unit formed with a coil pattern 6B on the front and back surfaces of an insulating base material 5B (both ends of the coil pattern 6B on the front and back surfaces in this example are It is connected to the lands 8 on the front and back surfaces, and is commonly connected in parallel by the terminals 4 passing through the lands 8, but may be connected in series by the through-hole conductors 7) and the insulating base material 5C. And a coil unit having a coil pattern 6C connected by a through-hole conductor 7 on the inner peripheral side on the front and back surfaces of the first and second coil patterns 6A to 6C. The insulating material 10 is interposed between the coil units, and the front and back surfaces of the plurality of coil units are covered with the insulating material 10 and laminated, and integrally fixed. Are those that you configured. Second magnetic cores 2 and 3 forming a magnetic path together with the first magnetic core 9 are assembled to the substrate.

In this configuration, the coil patterns 6A to 6A
6C is used as a primary winding and the other is used as a secondary winding. Thus, in the present invention, the number of stacked coil units is set according to the application.

FIG. 4 is a layer structure diagram showing another embodiment of the coil component according to the present invention, and FIG. 5 is a sectional view thereof. 5A to 5C in the figure are insulating base materials provided with the coil patterns 6A to 6C whose front and back surfaces are connected to each other as described above. 11
Are coil patterns 6A to
This is a third magnetic core disposed at the center of 6C and interposed therebetween.

The thickness of the third magnetic core 11 is set to be larger than the total thickness of the opposing coil patterns 6A and 6B or 6B and 6C. As an example, the thickness of the coil patterns 6A to 6C is 200 μm, and the thickness of the third magnetic core 11 is 460 μm. Therefore, when these coil units are stacked, the coil patterns 6A, 6A
An interval of about 60 μm is formed between B or between 6B and 6C.

The first magnetic core 9 is provided on the uppermost insulating base material 5.
A is arranged at the center of the upper surface and at the center of the lower surface of the lowermost insulating base material 5C. In this example, the first magnetic core 9
Is the same as the thickness of the coil patterns 6A and 6C.
It was set to 00 μm. The upper surface of the uppermost coil pattern 6A and the first magnetic core 9 and the lower surface of the lowermost coil pattern 6C are covered with an insulating material 10, respectively.
Before cutting the laminated body into individual chips, the flow resin 12 is sealed and cured in a vacuum state between the coil units, so that the opposing coil patterns 6A, 6B, 6
B and 6C are insulated. A substrate is formed by integrating these coil units together with the first magnetic core 9 and the upper and lower insulating materials 10.

By assembling the second magnetic cores 2 and 3 having the above-mentioned structure on the substrate thus configured,
And the first magnetic core 9 and the third magnetic core 11 constitute a magnetic path.

Thus, at the center of the coil pattern,
Opposite coil patterns 6A and 6B, or 6B and 6C
By sandwiching the third magnetic core 11 which is thicker than the total thickness, the insulating material between the coil units becomes unnecessary, and only one third magnetic core 11 between the coil units is required, and the number of parts is reduced. In addition, insulation between the opposing coil patterns can be easily performed by the encapsulated resin 12. Further, the interval between the coil patterns can be adjusted by the thickness of the third magnetic core.

FIG. 6A is a perspective view showing a choke coil according to another embodiment of the coil component of the present invention, FIG. 6B is an exploded perspective view thereof, FIG. 7 is a layer structure diagram thereof, and FIG. It is sectional drawing. In the present embodiment, the side legs 3a of the second magnetic core 3 shown in FIG. 1 are eliminated, and the fourth magnetic core 13 built in the substrate 1A is replaced by It is arranged on the outer peripheral side of the coil pattern 6. 6 to 8, the same reference numerals as those in FIGS. 1 and 2 indicate components that perform the same functions.

In the present embodiment, the first magnetic core 10 and the second magnetic core 2 at the center of the coil component,
3A, the second magnetic cores 2 and 3A and the fourth magnetic core 1
3 is also formed.

FIG. 9 shows a structure having the fourth magnetic core 13 as shown in FIG.
FIG. 9 is a layer structure diagram showing an example applied to a structure in which layers are interposed with zeros interposed therebetween.

FIG. 10 shows an example in which the structure having the fourth magnetic core 13 is applied to a structure in which the third magnetic core 11 is interposed between coil units as shown in FIGS. FIG.

[0034]

According to the first and second aspects of the present invention, the second magnetic core is built in a part of the substrate made of the laminated body.
The processing of the through hole for inserting the center leg of the magnetic core becomes unnecessary. Therefore, man-hours can be reduced, which contributes to cost reduction.

Further, since the first magnetic core is arranged inside the substrate made of the laminated body, the gap between the first magnetic core and the second magnetic core is dispersed, and the heat generation of the coil due to the leakage magnetic flux is greatly reduced. For this reason, it is not necessary to reduce the magnetic flux by increasing the size of the core, or to provide a space between the gap and the coil, thereby enabling downsizing.

According to the third aspect, between the coil units,
Since the third magnetic core thicker than the total thickness of the opposing coil patterns is sandwiched between the coil units, there is no need for an insulating material between the coil units, and only one third magnetic core between the coil units is required. In addition, the number of parts can be further reduced.

According to the fourth aspect of the present invention, the resin is sealed between the opposed coil patterns in the third aspect, so that the insulating process is simplified as compared with the case where an insulating material is applied on the coil pattern. .

[Brief description of the drawings]

FIG. 1A is a perspective view showing a choke coil (inductor) which is an embodiment of a coil component of the present invention,
(B) is an exploded perspective view thereof.

FIG. 2A is a diagram showing a layer structure of a substrate of the coil component of FIG. 1;
(B) is a sectional view of the coil component. .

FIG. 3 is a layer structure diagram showing a transformer as another embodiment of the coil component of the present invention.

FIG. 4 is a layer structure diagram showing a transformer according to another embodiment of the coil component of the present invention.

FIG. 5 is a cross-sectional view of the transformer of FIG.

FIG. 6A is a perspective view showing a choke coil (inductor) according to another embodiment of the coil component of the present invention,
(B) is an exploded perspective view thereof.

FIG. 7 is a layer structure diagram showing a transformer according to another embodiment of the coil component of the present invention.

FIG. 8 is a sectional view of the transformer of FIG. 7;

FIG. 9 is a layer structure diagram showing a transformer as another embodiment of the coil component of the present invention.

FIG. 10 is a layer structure diagram showing a transformer as another embodiment of the coil component of the present invention.

FIG. 11A is a perspective view showing a conventional coil component,
(B) is an exploded perspective view thereof.

[Explanation of symbols]

1, 1A: substrate, 1a: through hole, 2, 3, 3A:
Second magnetic core, 4: terminal, 5, 5A to 5C: insulating base material, 6, 6A to 6C: coil pattern, 7: through-hole conductor, 8: land, 9: first magnetic core, 10: insulating Material, 11: third magnetic core, 12: encapsulating resin, 13: fourth magnetic core

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 37/00 H01F 15/02 D

Claims (4)

[Claims] 1. A printed coil pattern having a thickness of 80 to 300 μm is formed on the front and back surfaces of an insulating base material, and a thickness substantially equal to or slightly smaller than the thickness of the coil pattern is formed at the center of the coil pattern on the front and back surfaces. A first magnetic core is disposed with the insulating base material interposed therebetween, a substrate is formed by covering the insulating base material having the coil pattern and the first magnetic core with an insulating material, and a magnetic path is formed together with the first magnetic core. A coil component, wherein a second magnetic core to be configured is mounted on the substrate. 2. The method according to claim 1, wherein each of the plurality of insulating substrates has an 80
A printed coil pattern having a thickness of about 300 μm is formed, and a first magnetic core having substantially the same thickness as or slightly thinner than the thickness of the coil pattern is disposed at the center of the coil pattern on the front and back surfaces with the insulating base material interposed therebetween. And a plurality of coil units having the coil pattern and the first magnetic core are laminated with an insulating material interposed therebetween.
A coil component, wherein a substrate is formed by covering an uppermost layer and a lowermost layer with an insulating material, and a second magnetic core forming a magnetic path together with the first magnetic core is assembled to the substrate. 3. The method according to claim 1, wherein the front and back surfaces of the plurality of insulating substrates have a thickness of 80 to 300.
forming a printed coil pattern having a thickness of μm, and forming a plurality of insulating base materials having the coil pattern on a third sheet having a thickness larger than the total thickness of the opposing coil patterns.
The first magnetic core having substantially the same thickness as or slightly thinner than the thickness of the coil pattern is disposed at the center of the coil pattern on the front and back surfaces of the laminated body. Further, a substrate is formed by covering the front and back surfaces of the laminate with an insulating material, and a second magnetic core forming a magnetic path together with the first and third magnetic cores is assembled to the substrate. Coil parts. 4. The coil component according to claim 3, wherein an insulating resin for insulating between the opposed coil patterns is sealed.