JPH11176648A - Substrate with transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate protrusion of a transformer and thin whole body of a substrate with the transformer, by a method where a coil is accommodated in a hole of a sub-substrate, the sub-substrate and the coil are covered with a tape and fixed, E-cores are inserted in a part of a central hole of the coil from both sides and fixed, and mounting is performed as the transformer. SOLUTION: A coil 2 is accommodated in a hole of a sub-substrate 11, a magnetic pole part of the center of an E-core 1 is inserted in a central aperture part of the coil 2 from the back side. A hole is formed in an insulating tape 15 so as to avoid a part where the E-core 1 is in contact with an E-core 2 aligned with the E-core 1 or a part having a specified gap between the E-core 1 and the E-core 2. A central aperture part of the coil 2 in which the E-cores are inserted and a part from which the upper and the lower E-cores 1, 2 are inserted are not covered with the insulating tape 15. A magnetic circuit of a transformer is so constituted that central magnetic pole parts of the respective E-cores 1, 2 face with each other. As a result, protrusion of the transformer can be eliminated, and the whole body of a substrate with the transformer can be thinned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a board with a transformer having a transformer mounted on the board.

[0002]

2. Description of the Related Art Conventionally, a transformer is mounted on a substrate and mounted by soldering like other electronic components to form a module.

Further, in order to reduce the thickness of a transformer mounted on a substrate, the thickness of a ferrite core constituting the core of the transformer and the thickness of a coil have been reduced.

[0004]

However, even in the above-described method for realizing a thin transformer, there is a structural limit to the thinning of the transformer. There is a problem that it protrudes above the substrate by the thickness of the substrate.

There is another problem that the insulation between the core and the coil cannot be sufficiently obtained by reducing the thickness of the small transformer mounted on the substrate. The present invention solves these problems by opening a hole in a sub-board or FPC, mounting a core, a coil, and a transformer made of the core on the hole, reducing the height, and further forming a recess or hole in the main board. It is an object of the present invention to mount the sub-substrate 11 integrated with the transformer on the portion of the above-mentioned part to eliminate the protrusion of the transformer, thereby realizing a thinner substrate with a transformer.

[0006]

Means for solving the problem will be described with reference to FIGS. 1, 4 and 5. FIG. Figure 1,
4 and 5, the sub-board 11 is for mounting a transformer.

[0007] The E core and the I core are cores constituting a transformer. The coil is a coil (winding) constituting the transformer. The tape 15 is used for the coil and the core to
It is for fixing to 1.

The main board 21 is a board on which the transformer on the sub-board 11 is inserted and fixed. Next, the structure will be described.

[0009] The coil is inserted into the hole of the sub-substrate 11, and the sub-substrate 11 and the coil are covered with a tape 15 and fixed.
E-cores (E-core 1 and E-core 2) are inserted into the center hole of the coil and fixed from both sides, and the transformer is mounted on the sub-board 11.

An I-core is inserted into the hole of the sub-substrate 11, and the outer periphery is fixed with a tape 15 and fixed. The center opening of the coil is inserted into the center magnetic pole of the E-core. The transformer is mounted on the sub-board 11.

An E core is inserted into the hole of the sub-substrate 11 and the outer periphery is fixed with a tape 15 so as to be fixed. The center opening of the coil is inserted into the center magnetic pole of the E core. The transformer is mounted on the sub-board 11 by being positioned and fixed to the fixed E core.

A transformer mounted on the sub-board 11 is inserted into the dent or hole of the main board 21 and both terminals or pads are soldered while the sub-board 11 is in contact with the main board 21. I try to connect.

A coil is connected to a pad or a terminal on the sub-substrate 11 or the thin film substrate, and a pad or a terminal provided on the sub-substrate 11 or the thin film substrate is connected to a pad or a terminal on the main substrate 21. .

Further, the tape 15 is a semi-solidified insulating tape so that the coil is insulated from the core or the like or a predetermined gap is formed between the cores. Therefore,
A hole is formed in the sub-board 11 or FPC, and a core, a coil, and a transformer composed of the core are mounted on the hole to reduce the height. By mounting the board 11 and eliminating the protrusion of the transformer, the thickness of the entire board with a transformer can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, various structural examples of the present invention will be sequentially described in detail with reference to FIGS. FIG. 1 shows a structural diagram of one embodiment of the present invention. This shows a structural diagram in a case where the coil 2 is housed in a hole of the sub-board 11, and the center magnetic pole portions of the E-core 1 and E-core 2 are inserted into the center opening of the coil 2 from both sides and fixed.

In FIG. 1, a coil 2 is provided on a sub-substrate 11.
And a coil having a thickness just enough to fit into the hole, and having an opening for inserting the E-core 1 in the center. The coil 2 is an air core and is formed by winding a self-adhesive (self-fusing) coil to form an air core coil.

The E core 1 has a central magnetic pole portion of the E core 1 inserted from the back side into a central opening of the coil 2 inserted into the hole of the sub-substrate 11. Tape 15
Is an insulating tape for fixing the coil 2 to the sub-substrate 11, wherein the tape 15 is provided so as to avoid a portion where the E-core 1 and the E-core 2 to be aligned later contact or have a predetermined gap. (FIG. 2 will be described later).

The terminals 13 are provided on the sub-substrate 11 and
As shown in (e), the sub-board 11 is fixed to the main board 21 by soldering and the coil 2 is electrically connected to the main board.

The pad 14 is a pad for soldering an end of a coil constituting the coil 2. The main board 21
This is a substrate that is provided with a hole, into which a transformer of the sub-substrate 11 is inserted and fixed, thereby achieving a reduction in thickness.

FIG. 1A shows a state in which the coil 2 is mounted and the tape 15 is wound around the outer circumference and covered. In this state, the coil 2 is inserted into the hole of the sub-substrate 11, and the tape 1
At 5, the coil 2 is fixed. On this occasion,
The tape 15 does not cover the central opening of the coil 2 into which the E core is inserted and the upper and lower portions into which the E cores 1 and 2 are inserted.

FIG. 1B shows the E cores 1 and 2. The E-cores 1 and 2 constitute the magnetic circuit of the transformer by inserting the magnetic poles at the center from the front and back of FIG. The center circle is the center magnetic pole portion of the E core, and the upper and lower rectangular portions are the outer magnetic pole portions.

FIG. 1C shows that the E core 1 is connected to the sub-substrate 11.
Shows a state inserted from behind. In this state, the E core 1 is inserted into the hole of the sub-board 11 and the central opening of the coil 2 as shown.

FIG. 1D shows the E core 2 as shown in FIG.
2 shows a state in which it is placed and fixed from above. In this state, it can be seen that the E-core 2 comes into contact with the E-core 1 as shown, forming a magnetic circuit.

FIG. 1E is a sectional view taken along the line AA of FIG. 1D. In this state, as shown in the figure, it can be seen that the coil 2 is housed in the hole of the sub-substrate 11 with the same thickness as the sub-substrate 11, and the E-core 1 is located below and the E-core 2 is located above. . Further, with the portion of the sub-board 11 where the transformer is located in the hole of the main board 21, the terminals 13 on the sub-board 11 are positioned on the pads of the main board 21 and soldered. 21 and the electrodes of the coil 2 are connected. As a result, the lower part of the transformer mounted on the sub-substrate 11 in the figure fits into the hole of the main board 21, and the transformer is inserted in the hole than when the transformer is mounted directly on the main board 21. An E-core 1 is included, and the height of the E-core 1 is kept low, so that a reduction in thickness can be realized.

As described above, the coil 2 is housed in the hole of the sub-substrate 11, and the E cores 1 and 2 are placed on both sides of the coil 2 from both sides.
And fix it by inserting it into the center hole of
The transformer is mounted on the sub-substrate 11, and the sub-substrate 11 is mounted so that the transformer is inserted into the hole of the main substrate 21, thereby making it possible to reduce the overall thickness of the substrate with the transformer.

FIG. 2 shows an example of the tape of the present invention. This tape 15 is the tape 15 of FIG. 1 described above, in which the coil 2 is inserted into the hole of the sub-substrate 11, and the outside is shown in FIG.
The coil 2 and the sub-substrate 11
And the coil 2 and the sub-substrate 11 are bonded to each other. This tape 15 has a hole at the position of the opening at the center of the coil 2 (the magnetic pole part at the center of the E cores 1 and 2) as shown in the figure. Further, the holes do not hinder formation of a predetermined gap between the E core 1 and the E core 2 or between the I core and the E core 2. If the thickness of the tape 15 does not hinder the formation of the predetermined gap, it is not necessary to avoid the holes. The tape 15 is a semi-solidified resin sheet mixed with insulating particles having a predetermined particle size or glass fibers having a predetermined thickness.
When the gap having a predetermined thickness can be formed when the tape 15 is cured by pressing and heating
It is not necessary to make a hole in 5.

In FIG. 2, one piece corresponds to the length when the tape 15 shown in FIG. 1A just makes one round as shown. As described above, by bonding the tape 2 to the sub-substrate 11 by covering the outer periphery of the coil 2 as shown in FIG. It is possible to hold.

FIG. 3 shows a structural diagram (part 1) of the present invention. This is based on the FPC (sub-substrate 1) in the configuration of FIG.
1 shows an example in which the coil 1 is added above or inside. FIG. 3A is a side cross-sectional view as viewed from the AA direction in FIG. 1D described above, and FIG. 3B is a view from the BB direction in FIG. 1D described above. FIG. Here, the coil 1 is a thin-film spiral coil formed on or in an FPC (flexible printed circuit board). As shown, a thin-film coil 1 is formed on or in the FPC around the hole of the FPC, and a coil 2 (an air-core coil wound with a self-fusing wire rod) is formed in the hole as described above. ), The coil 2 and the outer periphery of the FPC are wound and adhered with a tape 15 as shown in the figure, and the E-core 2 and the E-core 1 are inserted and fixed from above and below. The gap is provided as needed so that the gap between the center magnetic poles of the illustrated E cores 1 and 2 becomes a predetermined gap. In addition, a coil is formed in a spiral shape in the portion described as the coil 1 (FPC) in FIG. 3A and the portion described as the coil 1 (FPC) in FIG. 3B. Coil 1
As shown in the figure, a thin-film coil is formed avoiding the magnetic pole portions of the E cores 1 and 2 and the central opening of the coil 2.

FIG. 3C schematically shows a state in which the FPC on which the transformers of FIGS. 3A and 3B are mounted is mounted on the main board 21. In this case, as shown in the figure, the coil 2 is inserted into the hole of the FPC (the FPC with the coil 1), and the E core is inserted into the hole from above and below and fixed. Since it is fixed so that it fits in the hole, a part of the E cores 1 and 2 protrudes above and below the FPC, and the upper part in the figure fits into the hole part of the main board 21 and the lower part Need only protrude downward from the main board 21, and the main board 2
1 can be made thinner.

FIG. 4 shows a structural diagram (part 2) of the present invention. In this case, a structural example is shown in which the transformer does not protrude below the hole of the sub-substrate 11. FIG. 4A shows an example in which an I core and an E core 2 are used. In the case of this example, as shown in the figure, the I-core is inserted into the hole of the sub-substrate 11, the I-core and the sub-substrate 11 are fixed with the tape 15, and the center opening of the coil 2 is What was put in the central magnetic pole portion was placed and fixed on the I-core.

FIG. 4B shows an example in which the E core 1 and the E core 2 are used. In the case of this example, as shown in the figure, the E-core 1 is inserted into the hole of the sub-substrate 11, the E-core 1 and the sub-substrate 11 are fixed with the tape 15, and the opening at the center of the coil 2 is inserted into the E-core. E core 1
It is fixed on the top.

FIG. 4C shows a state in which the sub-substrate 11 on which the transformers shown in FIGS. 4A and 4B are mounted is fixed to a main substrate 21. In this case, the portion of the E core / I core constituting the transformer does not protrude below the sub-substrate 11, so that the protruding portion only extends upward as shown in the figure, and is accommodated in the hole of the main substrate 21. As a result, the thickness can be reduced.

FIG. 5 is a structural diagram (part 3) of the present invention. In this case, the transformer is mounted on the thin FPC 22 and mounted on the main board 21. FIG. 5A shows a side sectional view. As shown, thin FP
E core 1 on C (flexible printed circuit board) 22
Alternatively, a transformer is formed by mounting the I-core, the coil, and the E-core 2 and inserted into a hole of the main board 21 as shown in the figure, and the electrodes 23 of the FPC 22 and the pattern 24 of the main board 21 are soldered. And connect the coil.

FIG. 5B is a side sectional view showing the mounting state of FIG. 5A for easy understanding. As shown, a transformer (E core 1 / I core, coil, E core 2) is formed on the FPC 22 and the transformer is mounted on the main board 2
As shown in the figure, almost all of the height of the transformer can be mounted on the thick portion of the main board 21 and almost no downward protrusion of the main board 21 is achieved. The thinning of the substrate 21 is described in FIG.
(C) can be further advanced.

[0035]

As described above, according to the present invention,
A hole is formed in the sub-board 11 or FPC, and a core, a coil, and a transformer made of the core are mounted on the hole to reduce the height. Since the structure in which the substrate 11 is mounted to eliminate the protrusion of the transformer is employed, the thickness can be reduced when the transformer is mounted on the main substrate 21.

[Brief description of the drawings]

FIG. 1 is a structural diagram of one embodiment of the present invention.

FIG. 2 is an example of a tape of the present invention.

FIG. 3 is a structural diagram (No. 1) of the present invention.

FIG. 4 is a structural diagram (No. 2) of the present invention.

FIG. 5 is a structural diagram (part 3) of the present invention.

[Explanation of symbols]

 11: Sub-board 13: Terminal 14: Pad 15: Tape 21: Main board 22: FPC 23: Electrode 24: Pattern

Claims (7)

[Claims] 1. A substrate with a transformer having a transformer mounted on the substrate, a substrate provided with a hole, a coil having an opening at the center for inserting a central magnetic pole portion of an E core and housed in the hole of the substrate, A substrate with a transformer, comprising: a tape that covers an outer periphery except for an opening of the coil in a state where the coil is housed in a hole of the substrate; and E-cores inserted into the opening of the coil from both sides. . 2. A substrate with a transformer having a transformer mounted on the substrate, the substrate having a hole, the I-core accommodated in the hole of the substrate, and the I-core accommodated in the hole of the substrate. A tape covering the outer periphery except for a central magnetic pole portion of the E core facing the E core; and an E core mounted on the I core by inserting an opening of the coil into the central magnetic pole portion. substrate. 3. A board with a transformer having a transformer mounted on the board, the board having a hole, the E core housed in the hole of the board, and the E core housed in the hole of the board. A tape with a transformer, comprising: a tape covering an outer periphery except for a central magnetic pole portion of the above; and a second E-core which is mounted on the E-core by inserting an opening of the coil into the central magnetic pole portion. 4. A method in which a transformer mounted on the substrate is inserted into a dent or a hole of the main substrate and both terminals or pads are connected by soldering while the substrate is in contact with the main substrate. The substrate with a transformer according to any one of claims 1 to 3, wherein: 5. A transformer comprising an I-core or an E-core mounted on a thin-film substrate, and a coil and an E-core mounted thereon and bonded to form a transformer. The transformer is mounted on the thin-film substrate in a dent or hole of the main substrate. Wherein the terminals or pads are connected by soldering while the thin film substrate is in contact with the main substrate. 6. The method according to claim 1, wherein the coil is connected to a pad or a terminal on the substrate or the thin film substrate, and a pad or a terminal provided on the substrate or the thin film substrate is connected to a pad or a terminal on the main substrate. The substrate with a transformer according to claim 1. 7. The substrate with a transformer according to claim 1, wherein said tape is an insulating tape in a semi-solid state.