FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION [See section 10, Rule 13]
ROTATION DETECTION DEVICE AND METHOD OF MANUFACTURING ROTATION DETECTION DEVICE;
MITSUBISHI ELECTRIC
CORPORATION, A CORPORATION ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

device in the first embodiment.
FIG. 4 is a top view illustrating an interlayer substrate of the circuit board of the rotation detection device in the first embodiment.
FIG. 5 is a bottom view illustrating a lower layer substrate of the circuit board of the rotation detection device in the first embodiment.
FIG. 6 is a cross-sectional view of the circuit board of the rotation detection device in the first embodiment.
FIG. 7 is a diagram illustrating the fitted state of a combined magnetic wire in the rotation detection device in the first embodiment.
FIGS. 8(a) to 8(f) are cross-sectional views illustrating a process of manufacturing the circuit board of the rotation detection device in the first embodiment.
FIG. 9 is a cross-sectional view of a circuit board of a rotation detection device in a second embodiment.
FIG. 10 is a perspective view illustrating the schematic configuration of a rotation detection device in a third embodiment.
FIG. 11 is an exploded perspective view of the rotation detection device in the third embodiment.
FIG. 12 is a cross-sectional view of a circuit board of the rotation detection device in the third embodiment.
FIG. 13 is an exploded perspective view of a rotation detection device in a fourth embodiment.
FIG. 14 is a cross-sectional view of a circuit board of a rotation detection device in a fifth embodiment.
FIGS. 15(a) and 15(b) are process cross-sectional drawings illustrating a process of manufacturing a combined magnetic wire used in a process of manufacturing the rotation detection device in the fifth embodiment.
FIGS. 16(a) to 16(e) are process cross-sectional

drawings illustrating a process of manufacturing the circuit board of the rotation detection device in the fifth embodiment.
Description of Embodiments
[0013] Hereinafter, a rotation detection device and a method of manufacturing the rotation detection device according to embodiments of the present invention will be described in detail with reference to the drawings. These embodiments are not intended to limit this invention, and can be modified as appropriate without departing from the scope of the invention. In the drawings described below, scales of layers or members may be different from actual ones to facilitate understanding, and the same applies to those between the drawings. In some cross-sectional views, there is a case that hatching is not given to make the drawings easier to see. [0014] First Embodiment.
FIG. 1 illustrates a perspective view of the schematic configuration of a rotation detection device in the first embodiment. FIG. 2 is an exploded perspective view of the rotation detection device in the first embodiment. FIG. 3 is a top view illustrating an upper layer substrate of a circuit board of the rotation detection device in the first embodiment. FIG. 4 is a top view illustrating an interlayer substrate of the circuit board of the rotation detection device in the first embodiment. FIG. 5 is a bottom view illustrating a lower layer substrate of the circuit board of the rotation detection device in the first embodiment. FIG. 6 is a cross-sectional view of the circuit board of the rotation detection device in the first embodiment. FIG. 7 is a diagram illustrating the fitted state of a combined magnetic coil in the rotation detection

magnetic wire 350 disposed in the central portion of the circuit board 301 is above the rotation axis X0 of the rotating shaft 100.
[0019] Next, the detailed configurations of the circuit board 301, the combined magnetic wire 350, and the pickup coil 360 constituting the detector 300 for realizing the rotation detection device in the first embodiment will be described with reference to FIGS. 3 to 5. In FIGS. 3 to 5, the circuit board 301 is in a disk shape for explanatory convenience, but may be a substrate in a polygonal shape such as a quadrilateral shape or an octagonal shape. The circuit board 301 includes three layers. FIGS. 3 to 5 are a top views illustrating the upper layer 310 which is an upper layer substrate, a top view illustrating the interlayer 320 which is an interlayer substrate, and a bottom view illustrating the lower layer 330 which is a lower layer substrate, respectively. The upper layer 310 corresponding to the first layer of the circuit board 301 is constituted by, as illustrated in FIG. 3, a glass epoxy substrate which is an insulating substrate 311, and the wirings 312 formed by patterning a copper foil formed on the insulating substrate 311. The second layer, that is, the interlayer 320 has, as illustrated in FIG. 4, a glass epoxy substrate which is an insulating substrate 321, the recessed groove 340 formed in the insulating substrate 321, and the combined magnetic wire 350 fitted in the recessed groove 340. The lower layer 330 corresponding to the third layer is formed of, as illustrated in FIG. 5, a glass epoxy substrate which is an insulating substrate 331, and the wirings 332 formed by patterning a copper foil formed on the insulating substrate 331. And, the circuit board 301 is constituted by the through holes TH for connecting via the interlayer 320 between the wirings 312 on the upper layer 310 and the wirings 332 formed on the lower surface

using a fixed member such as a housing, and thus the combined magnetic wire 350 can be disposed on the rotation center of the magnet, and a rotation detection device having the highest power generation efficiency and the highest detection efficiency can be realized. [0022] FIG. 6 is a cross-sectional view illustrating a cross section of the circuit board 301along a thickness direction. The wirings 312 and 332 are formed on the top surface of the upper layer 310 corresponding to the first layer and on the bottom surface of the lower layer 330 corresponding to the third layer, respectively. The wirings 312 and 332 respectively formed on the first layer and the third layer are connected via the through holes TH so as to form the pickup coil 360. The combined magnetic wire 350 is disposed in the U-shaped portion in the second layer.
[0023] Since a larger pulse voltage may be produced when the pickup coil 360 is wound nearby the combined magnetic wire 350, it is preferable that each of the insulating substrate 311 of the upper layer 310 and the insulating substrate 331 of the lower layer 330 has a thin thickness as much as possible.
[0024] It is to be noted that, like a configuration in a modification of the interlayer 320 illustrated in FIG. 7, stoppers 370 made of soft magnetic bodies of ferrite or the like may be fitted toboth ends of the combined magnetic wire 350. In a configuration in which the combined magnetic wire 350 is inserted afterward, a stopper 370 is formed and embedded for one end only, and then the stopper 370 may be used as a stopper at the time of inserting the combined magnetic wire 350, by which positional accuracy can be increased along with magnetic collection effect. It is to be noted that, after the combined magnetic wire 350 is inserted, another

stopper 370 made of a soft magnetic body may be inserted to reach the other end of the combined magnetic wire 350 to cover the other end.
[0025] Next, a method of manufacturing the rotation detection device in the first embodiment will be described. FIGS. 8(a) to 8(f) areprocess cross-sectional drawings illustrating a process of manufacturing the rotation detection device in the first embodiment. First, as illustrated in FIG. 8(a), a copper foil 312S, which will serve as the wirings 312, is stuck onto the insulating substrate 311 made of a glass epoxy substrate. Then, as illustrated in FIG. 8(b), the copper foil is patterned by using photolithography to form the wirings 312. A copper foil 332S, which will serve asthe wirings 332, is likewise stuck onto the insulating substrate 331 constituting the lower layer 330, which is not illustrated. Then, the copper foil is patterned by using photolithography to form the wirings 332.
[0026] On the other hand, for the interlayer 320, as illustrated in FIG. 8(c), the insulating substrate 321 made of a glass epoxy substrate is prepared, and as illustrated in FIG. 8(d), the recessed groove 340 is formed by laser machining. The recessed groove 340 may be formed to pass through the interlayer 320.
[0027] Then, as illustrated in FIG. 8(e), the upper layer 310, the interlayer 320, and the lower layer 330 are stacked sequentially, and then subjected to a heat treatment.
[0028] Then, as illustrated in FIG. 8(f), laser irradiation is applied to the circuit board 301 to pass through the upper layer 310, the interlayer 320, and the lower layer 330 to form the through holes TH. Then the through holes TH are filled with a metal film corresponding to the conductor 333.

[0029] The combined magnetic coil 350 is inserted in the recessed groove 340 in the circuit board 301 formed in this manner. When inserting the combined magnetic wire 350, the combined magnetic wire 350 is inserted until it touches one stopper 370 made of ferrite at the back, and the other stopper 370 made of ferrite is fitted to the opening side. Then, positioning is performed with respect to the magnet for detection 200 formed on the top surface of the rotating shaft 100, and the circuit board 301 constituting the detector is fixed by using a fixture not illustrated, to obtain the rotation detection device illustrated in FIG. 1. [0030] As described above, the combined magnetic wire 350 is processed by the wire drawing process and the twisting process, and thus the combined magnetic wire 350 is likely to lose its characteristics under the application of stress. According to the rotation detection device of the first embodiment, after the circuit board 301 of the multi-layer wiring structure is formed using the interlayer 320 in which the recessed groove 340 is formed, the circuit board 301 is formed by inserting the combined magnetic wire 350 into the recessed groove 340. Therefore, it is possible to detect the rotation with high reliability without a decrease in measurement accuracy due to the loss of the characteristics. Further, the combined magnetic wire 350 is disposed in the recessed groove 340, and thus is protected from an external force not only during manufacturing but also during use, by which characteristic degradation of the combined magnetic wire 350 can be suppressed. Furthermore, only by disposing the combined magnetic wire 350 in alignment with the recessed groove 340, the positional relationship with the pickup coil 360 can be controlled with reliability. [0031] The reliable alignment eliminates the need for a

in the first embodiment. The connection layer 500 is configured by an insulating substrate. The lower-side upper layer 510 includes wirings 512 formed by patterning a copper foil formed on an insulating substrate 511 in a similar manner to the upper layer substrate used in the first embodiment. The lower-side interlayer 520 is provided by forming a recessed groove 540 in an insulating substrate 521. The lower-side lower layer 530 includes wirings 532 formed by patterning a copper foil formed on an insulating substrate 531, like the lower layer 330 used in the first embodiment. A laminated body including the lower-side upper layer 510, the lower-side interlayer 520, and the lower-side lower layer 530 is connected via the connection layer 500. Further, the second pickup coil 360B is formed by a metal conductor 533 with which through holes TH passing between the wirings 512 onthe lower-side upper layer 510 andthe wirings 532onthe lower-side lower layer 530 are filled. On the upper-layer side, as in the first embodiment, the first pickup coil 360A is formed by a metal conductor 333 with whichthrough holes TH passing through the wirings 312 onthe upper layer 310 and the wirings 332 on the lower layer 330 are filled. The first pickup coil 360A on the upper-layer side and the second pickup coil 360B on the lower-layer side are disposed in directions orthogonal to each other.
[0050] In a manufacturing process, first and second detectors formed in a similar manner as in the process in FIG. 8 are connected in orthogonal directions via the connection layer 500 to obtain the circuit board 301SS, in which the first and second combined magnetic wires 350A and 350B are inserted to form a detector illustrated in FIG. 12. [0051] The rotational direction of magnets has a clockwise direction and a counterclockwise direction. A

We Claim
1. A rotation detection device comprising:
a magnet for detection (200) mounted on a rotating body (100) rotating about a rotation axis (X0); and
a detector (300) including a multi-layer circuit board (301) disposed opposite to the magnet for detection (200), to detect rotation of the rotating body (100),
the detector (300) comprising:
a combined magnetic wire (350) provided at an interlayer (320) of the circuit board (301), disposed on an extension of the rotation axis (X0) and exhibiting a large Barkhausen effect; and
a pickup coil (360) including wirings on the circuit board (301) and a conductor (333) with which through holes (TH) provided in the circuit board (301) are filled, to surround the combined magnetic wire (350).
2. The rotation detection device according to claim 1,
wherein the detector (300) comprising a groove (340; 540)
provided in the interlayer (320) of the circuit board (301),
having a center (O2) on the extension of the rotation axis
(X0), and being orthogonal to the rotation axis (X0), and
the pickup coil (360) is disposed around the groove (340; 540).
3. The rotation detection device according to claim 2,
wherein the pickup coil (360) comprises:
an inner layer coil (360i) formed of wirings on the circuit board (301) and a conductor (333) with which through holes (TH) are filled, and surrounding the combined magnetic wire (350); and
an outer layer coil (360o) formed of wirings on the circuit board (301) and a conductor (333) with which

through holes (TH) are filled, and surrounding the inner layer coil (360i),
the inner layer coil (360i) and the outer layer coil (360o) are connected in series.
4. The rotation detection device according to claim 2 or
3, wherein
the groove (340; 540) comprises a first groove (340) and a second groove (540) that have a center located on the extension of the rotation axis (X0), are provided at a fixed distance from each other on the extension of the rotation axis (X0), and extend in directions orthogonal to each other, and wherein
the rotation detection device comprising:
a first combined magnetic wire (350A) incorporated in the first groove (340);
a second combined magnetic wire (350B) incorporated in the second groove (540);
a first pickup coil (360A) formed of wirings on the circuit board (301) and a conductor (333) with which through holes (TH) are filled, to surround the first combined magnetic wire (350A); and
a second pickup coil (360B) formed of wirings on the circuit board (301) and a conductor (333) with which through holes (TH) are filled, to surround the second combined magnetic wire (350B).
5. The rotation detection device according to any one of
claims 2 to 4, wherein
the circuit board (301) is formed of a multi-layer wiring substrate in which a wiring layer and an insulating layer are stacked alternately,
the groove (340; 540) is formed in the insulating

layer, a stopper (370) being fitted in at least one end of the groove (340; 540), and
a length of the groove (340; 540) from a center of the circuit board (301) to the stopper (370) is L/2 where L is a length of the combined magnetic wire (350).
6. The rotation detection device according to claim 5, wherein the stopper (370) is a ferrite embedded layer.
7. The rotation detection device according to any one of claims 1 to 6, wherein cylindrical soft magnetic bodies are fitted to both ends of the combined magnetic wire (350).
8. The rotation detection device according to any one of claims 4 to 7, wherein
the circuit board (301) is a disk-shaped substrate having a center axis on the extension of the rotation axis (X0), and
the pickup coils (360A; 360B) surrounding the first combined magnetic wire (350A) and the second combined magnetic wire (350B) orthogonal to each other on the center axis of the circuit board (301) are uniformly wound around along an entire length of the first combined magnetic wire (350A) and the second combined magnetic wire (350B).
9. The rotation detection device according to any one of claims 4 to 8, wherein the circuit board (301) has a soft magnetic layer on a first main surface opposite to the magnet for detection.
10. The rotation detection device according to any one of claims 3 to 8, wherein the circuit board (301) has soft magnetic layers on both sides thereof.

11. The rotation detection device according to any one of claims 1 to 10, wherein a processing circuit to process pulse voltage generated from the pickup coil (360) and to count the number of revolutions is mounted on the circuit board (301).
12. A method of manufacturing a rotation detection device that comprises:
a magnet for detection (200) mounted on a rotating body (100) rotating about a rotation axis (X0); and
a detector (300) including a multi-layer circuit board (301) disposed opposite to the magnet for detection (200), to detect rotation of the rotating body (100),
the detector (300) comprising:
a combined magnetic wire (350) provided at an interlayer (320) of the circuit board (301), disposed on an extension of the rotation axis (X0) and exhibiting a large Barkhausen effect; and
a pickup coil (360) including wirings on the circuit board (301) and a conductor (333) with which through holes (TH) provided in the circuit board (301) are filled, to surround the combined magnetic wire (350),
the method of manufacturing the rotation detection device comprising:
a step of manufacturing the circuit board (301), the step including:
a step of forming a pickup coil (360) with wirings and a conductor (333) with which through holes (TH) are filled, and forming a laminated body having a recessed groove (340; 540) for insertion into which the combined magnetic wire (350) is inserted; and
a step of inserting the combined magnetic wire (350) into the recessed groove (340; 540) in the laminated

body.
13. The method of manufacturing a rotation detection device
according to claim 12, wherein
the step of forming the laminated body includes: a step of stacking and firing a plurality of
ceramic green sheets on which wiring layers are formed
together with a dummy rod (D) interposed therebetween; and a step of pulling out the dummy rod (D) after the
firing step to form a cavity (H) corresponding to the
recessed groove (340; 540).
14. The method of manufacturing a rotation detection device
according to claim 13, wherein
the step of inserting the combined magnetic wire (350) includes:
a step of covering a periphery of the combined magnetic wire (350) with an insulating film (350i); and
a step of inserting the combined magnetic wire (350) covered with the insulating film (350i) into the cavity (H).

ABSTRACT
ROTATION DETECTION DEVICE AND METHOD OF MANUFACTURING ROTATION DETECTION DEVICE
A magnet for detection 200 mounted on a rotating shaft 100 rotating about a rotation axis X0, and a detector 300 disposed opposite to the magnet for detection 200 to detect rotation of the rotating shaft 100 are included. The detector 300 includes a multi-layer circuit board 301, a recessed groove that is provided in an interlayer 320 of the circuit board 301, has a center on an extension of the rotation axis X0, and is orthogonal to the rotation axis X0, a combined magnetic wire incorporated in the recessed groove and exhibiting a large Barkhausen effect, and a pickup coil 360 formed of wiring conductors on the circuit board 301 and a conductor with which through holes TH are filled, to surround the combined magnetic wire.