US3581015A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dynamic microphone
Assignee: Sony Group Corp
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Filing: 1967-12-26
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Granted: 1971-05-25
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Expires: 1987-12-26
Abstract
Abstract This specification discloses a novel dynamic microphone using a flat annular magnet formed of an anisotropic barium ferrite as a permanent magnet to establish a magnetic circuit. The present microphone is extremely flat and of an excellent tone quality, and it can be manufactured at low cost. Various modifications to the microphone of this type become easily possible, and therefore a variety of examples with unidirectional characteristics or other characteristics are disclosed in this specification.
Inventors
- 👤 Takeo Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:09
CPC Classifications
H; H04; H04R; H04R9/00; H04R9/02; H04R9/025; H04R1/00; H04R1/20; H04R1/22; H04R1/222
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
206 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnet coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be positioned in a gap defined by said magnetic coupling ring and said center pole; at lease one hole being formed in said center pole and said yoke extending therethrough; the space surrounded by said annular magnet, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, a double-walled cylindrical body being affixed to the bottom surface of said yoke so as to form an acoustic housing, said acoustic housing and said acoustic duct being acoustically communicated with each other through at least one hole having an acoustic resistor piece inserted therein, and a second acoustic resistor piece being provided in the hole extending through said center pole, the center portion of said yoke and the center portion of said double-walled cylindrical body.
Claim 2
Dependent Claim
206 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnet coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be positioned in a gap defined by said magnetic coupling ring and said center pole; at lease one hole being formed in said center pole and said yoke extending therethrough; the space surrounded by said annular magnet, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, a double-walled cylindrical body being affixed to the bottom surface of said yoke so as to form an acoustic housing, said acoustic housing and said acoustic duct being acoustically communicated with each other through at least one hole having an acoustic resistor piece inserted therein, and a second acoustic resistor piece being provided in the hole extending through said center pole, the center portion of said yoke and the center portion of said double-walled cylindrical body.
Claim 3
Dependent Claim
143 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be posiTioned in a gap defined by said magnetic coupling ring and said center pole; said annular magnet, said yoke and said magnetic coupling ring defining an acoustic housing; at least one recessed portion being formed in the upper side surface of said annular magnet and a hole being formed in said magnetic coupling ring in register with said recessed portion, thereby producing unidirectional characteristics.
Claim 4
Dependent Claim
143 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be posiTioned in a gap defined by said magnetic coupling ring and said center pole; said annular magnet, said yoke and said magnetic coupling ring defining an acoustic housing; at least one recessed portion being formed in the upper side surface of said annular magnet and a hole being formed in said magnetic coupling ring in register with said recessed portion, thereby producing unidirectional characteristics.
Claim 5
Dependent Claim
43 words
A dynamic microphone as set forth in claim 2, wherein a hole is formed in the center portion of said center pole extending therethrough and communicating with said acoustic housing at the lower end thereof, an acoustic resistor being provided in said hole.
Claim 6
Dependent Claim
154 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be positioned in a gap defined by said magnetic coupling ring and said center pole; the space surrounded by said annular ring, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, an acoustic housing being provided to cover at least a part of the side surface of said annular magnet, and said acoustic duct and housing being communicated with each other through at least one hole having an acoustic resistor.
Claim 7
Dependent Claim
154 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling ring secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to depend therefrom so as to be positioned in a gap defined by said magnetic coupling ring and said center pole; the space surrounded by said annular ring, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, an acoustic housing being provided to cover at least a part of the side surface of said annular magnet, and said acoustic duct and housing being communicated with each other through at least one hole having an acoustic resistor.
Claim 8
Dependent Claim
157 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to be positioned in a gap defined by said magnetic ring and sad center pole; the space surrounded by said annular magnet, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, an acoustic housing being provided to cover at least a part of the side surface of said annular magnet and the bottom surface of said yoke, and said acoustic duct and housing being acoustically communicated with each other through at least one hole having an acoustic resistor inserted therein.
Claim 9
Dependent Claim
157 words
A dynamic microphone, comprising an annular magnet formed of an anisotropic barium ferrite, a yoke affixed to the lower surface of said annular magnet, a magnetic coupling secured to the upper surface of said annular magnet, a center pole provided on the yoke coaxially with respect to said annular magnet, a diaphragm secured to said magnetic coupling ring, and a voice coil attached to said diaphragm in such a manner as to be positioned in a gap defined by said magnetic ring and sad center pole; the space surrounded by said annular magnet, said yoke and said magnetic coupling ring being adapted to serve as an acoustic duct, an acoustic housing being provided to cover at least a part of the side surface of said annular magnet and the bottom surface of said yoke, and said acoustic duct and housing being acoustically communicated with each other through at least one hole having an acoustic resistor inserted therein.
Claim 10
Dependent Claim
30 words
A dynamic microphone as set forth in claim 4, wherein at least one hole having an acoustic resistor therein is formed in said center pole and said yoke extending therethrough.
Claim 11
Dependent Claim
46 words
A dynamic microphone as set forth in claim 4, wherein at least one recessed portion is formed in the upper side surface of said annular magnet, and a hole is formed in said magnetic coupling ring in register with said recessed portion, thereby producing unidirectional characteristics.
Claim 12
Dependent Claim
30 words
A dynamic microphone as set forth in claim 5, wherein at least one hole having an acoustic resistor therein is formed in said center pole and said yoke extending therethrough.
Claim 13
Dependent Claim
46 words
A dynamic microphone as set forth in claim 5, wherein at least one recessed portion if formed in the upper side surface of said annular magnet, and a hole is formed in said magnetic coupling ring in register with said recessed portion thereby producing unidirectional characteristics.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |