US3324253A - Small-sized electroacoustic transducers - Google Patents
Small-sized electroacoustic transducers Download PDFInfo
- Publication number
- US3324253A US3324253A US316081A US31608163A US3324253A US 3324253 A US3324253 A US 3324253A US 316081 A US316081 A US 316081A US 31608163 A US31608163 A US 31608163A US 3324253 A US3324253 A US 3324253A
- Authority
- US
- United States
- Prior art keywords
- permanent magnet
- space
- diaphragm
- yoke
- pole piece
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R11/00—Transducers of moving-armature or moving-core type
- H04R11/06—Telephone receivers
Definitions
- the present invention relates to an improvement in the structure and performance of small-sized electroacoustic transducers such as earphones or microphones of small size.
- the invention has for its object to provide the transducers of the type which have improved power sensitivity, frequency characteristic and impedance characteristic, with less liability to variation in the performance due to variation in the property of permanent magnets and with high stability free from variation in the performance due to formation of rust on a gap surface.
- an electroacoustic transducer of small size comprising a cylindrical frame, a pole piece disposed centrally of said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the assembly of said pole piece, coil and permanent magnet, and -a plate of magnetic material disposed between said diaphragm and said cylindrical permanent magnet.
- FIG. 1a is a vertical sectional view of an embodiment of an electroacoustic transducer of the invention
- FIG. 1b is a sectional view taken along the line AA of FIG. la;
- FIG. is a perspective view of an annular plate of magnetic material used in the electroacoustic transducer of FIG. 1a;
- FIG. 2a is a vertical sectional view of another embodiment of the electroacoustic transducer of the invention.
- FIG. 2b is a sectional view taken along the line A-A of FIG. 2a; 7
- FIG. 20 is a perspective view of a cup-shaped member of magnetic material used in the transducer of FIG. 2a;
- FIG. 3a is a vertical sectional view of still another embodiment of the electroacoustic transducer of the invention.
- FIG. 3b is a sectional view taken along the line AA of FIG. 3a;
- FIG. 4a is a comparative vertical sectional view of an electroacoustic transducer, in which the left-hand side half shows the structure according to the invention and the right-hand side half shows a conventional design;
- FIG. 4b is an equivalent magnetic circuit of the transducer of conventional design
- FIG. 40 is also an equivalent magnetic circuit of the transducer embodying the invention.
- FIG. 4d is a characteristic curve of the electroacoustic transducer of the invention.
- FIG. 5a is an equivalent electroacoustic circuit of the transducer of the invention.
- FIG. 5b is an equivalent electroacoustic circuit of the conventional transducer.
- an electroacoustic transducer of the invention which comprises a cylindrical frame 1. Centrally of the cylindrical frame 1, there is disposed a columnar pole piece 2, about which a coil 3 is wound. A cylindrical permanent magnet 4 is concentrically disposed about the coil 3 and has a yoke 5 disposed below thereof.
- an annular space a is defined between the cylindrical frame 1 and the permanent magnet 4.
- an annular plate 6 of magnetic material is mounted on the upper face of the permanent magnet 4.
- a disc-like diaphragm 7 of magnetic material is disposed on the annular plate 6 so as to define a space a between the diaphragm 7 and the pole piece 2.
- an armature 8 of magnetic material is mounted on the upper face of the diaphragm 7.
- the electroacoustic transducer of the invention comprises an outer casing 9 of a cup-like shape, an upper opening of which is covered by a cap 10 of non-magnetic material such as aluminum.
- a space a and a space a are also formed between the outer casing 9 and the yoke 5, and between the diaphragm 7 and the can 10, respectively.
- An ear-plug 11 is provided on the cap 10 and has a passage 12 of sound bored therethrough.
- a bore 13 of small diameter is provided in the yoke 5 to provide communication between the spaces a and a
- a bore 14 of small diametenis provided in the annular plate 6 to provide communication between the spaces a and a Therefore, it will be known that, when the electroacoustic transducer of FIG.
- a signal current may be supplied to the coil 3 so that the diaphragm 7 and the armature 8 are made to oscillate to thereby generate sound.
- the electroacoustic transducer is utilized as a sound-electricity transducer, the diaphragm 7 and the armature 8 may be made to oscillate by sound so that a signal current can be taken out of the coil 3.
- the annular plate 6 of magnetic material is provided at a portion where the permanent magnet 4 is disposed opposite the lower face of the diaphragm 7, magnetic flux by the signal current can be concentrated into the annular plate 6 of magnetic material through a magnetic circuit comprising the pole piece 2- diaphragm 7 and armature 8-) annular plate 6 permanent magnet 4 and space a yoke 5 pole piece 2.
- the space a defined between the yoke and the outer casing 9 is made to communicate with the space a defined by the annular plate 6, cylindrical frame 1, cylindrical permanent magnet 4 and yoke 5 by means of the bore 13 provided in the yoke 5.
- the space a defined by the diaphragm 7, permanent magnet 4 and annular plate 6 is made to communicate with the space a by means of the bore 14 provided in the annular plate 6.
- the space a communicates with the sound passage 12.
- the provision of the bores 13 and 14 is effective for improvement in the frequency characteristic in that a resonance point in the order of 15 decibels which exists in a range between 1,000 to 2,000 cycles is dispersed to provide a flat frequency characteristic having resonance point below 10 decibels.
- FIGS. 2a and 2b Another embodiment of the electroacoustic transducer shown in FIGS. 2a and 2b is generally similar in the construction to the transducer shown in FIG. 1a.
- the annular plate 6 of magnetic material of FIG. 10 takes the form of a cup 106, which has not only an annular portion to abut the upper face of a permanent magnet 104, but also a cylindrical portion to depend downwardly therefrom so as to surround the permanent magnet 104 with a small space therebetween, as best shown in FIG. 20.
- An annular mem ber p is interposed between upper edges of a cylindrical frame 101 and the cup 106 of magnetic material to provide a suitable air tight relation therebetween.
- magnetic flux by a signal current passes a magnetic circuit comprising a pole piece 102- diaphragm 107 and armature 108 cup 106 of magnetic materialyoke 105- pole piece 102, in the manner as described with regard to FIG. 10. Since the magnetic flux passes through a small space defined between the cylindrical portion of the cup 106 and the cylindrical frame 101, magnetic resistance against the magnetic flux is made extremely small and the electroacoustic conversion performance can be markedly improved. It will further be understood that the frequency characteristic can also be improved as in the case of the embodiment of FIG. 1a.
- FIGS. 3a and 3b also shows still another embodiment of the electroacoustic transducer of the invention.
- the embodiment of FIGS. 3a and 3b is generally similar to the transducer of FIG. la, except that a cylindrical frame or outer casing 201 is made of magnetic material to dispense with any provision of a separate shielding casing.
- a gap 224 is provided between an annular plate 206 of magnetic material disposed on the upper face of a permanent magnet 204 and the cylindrical frame 201.
- an electroacoustic transducer In an electroacoustic transducer, upper and lower faces of an outer casing of non-magnetic material are covered by an electromagnetically shielding casing. Therefore, such electroacoustic transducer is disadvantageous in that the overall thickness is made thicker by the thickness of the shielding casing.
- the outer casing 201 is made of a magnetic material and acts to form a lower shielding casing in cooperation with a yoke 205.
- Such arrangement will eliminate the need of any lower shielding casing and is effective to reduce the thickness of the transducer, thus providing the electroacoustic transducer of a compact structure and a small size.
- three magnetic circuits can be formed, that is, a magnetic circuit comprising a pole piece 202- diaphragm 207 and armature 208- outer casing 201 of magnetic materialyoke 205 pole piece 202, a magnetic circuit comprising the pole piece 202 diaphragm 207 and armature 208 annular plate 206 of magnetic material outer casing 201- yoke 205 pole piece 202, and a magnetic circuit comprising the pole piece 2412- diaphragm 207 armature 208 shielding casing 209 outer casing 201- yoke 205- pole piece 202.
- FIGS. 4a4d provide a verification of excellency of the electroacoustic transducer of the invention over that of conventional design on a theoretical basis.
- a magnetic driving force Fm acting on a diaphragm 307 can be calculated by the following equation.
- Equation 2 when the Equation 2 is inserted in the Equation 1 and conditions L' d e (wherein L L r and U 4rNI are inserted therein, the following equation is obtained:
- the magnetic driving force Fm acting on the diaphragm 367 can be divided into three main components.
- further investigation will be made on the force F Changing the Equation 7,
- the force Fm acting on the diaphragm 307 is composed of the three component forces where,
- F is the attracting force caused by the permanent magnet (before displacement takes place)
- F is the force additionally produced by the displacement by the force
- F is the force caused by the signal current flowing through the coil
- the force F is directly related to a conversion gain (power sensitivity) and'is proportional to a produce of 5 (magnetic flux by the permanent magnet) by & (magnetic flux by the signal current) as will be apparent from the Equation 9.
- the magnetic flux by the permanent magnet may preferably be set at a suitable value which is not so excessive.
- FIG. 4b is the circuit of the conventional transducer shown on the right-hand side of FIG. 4a, where Rg Rg Rg and Ra designate a magnetic resistance due to an inner gap of the diaphragm, a magnetic resistance due to an outer gap of the diaphragm, and a magnetic resistance due to a gap between the cup and the yoke, and a magnetic resistance when considered from the side of the source of magnetic flux by the signal current.
- R Rg Rg among R Rg and Rg and the magnetic resistance Ra taken from the side of the source of magnetic flux by the signal current can be expressed as:
- FIG. 40 is the equivalent circuit of the transducer according to the invention, in which a magnetic resistance Ra taken from the side of the source of magnetic flux by the signal current can be expressed as:
- o ya o gs Rg in the equation designates a magnetic resistance by the magnetic shunt.
- a magnetic resistance Rb of FIG. 4b when taken from the side of the permanent magnet can be expressed as:
- a similar magnetic resistance Rb in FIG. 40 can likewise be expressed as:
- FIG. 4d illustrates a relation between the sensitivity and the degree of demagnetization during such demagnetization process. From the curve shown, it will be understood that a stable and well balanced operation can be obtained by selecting a point S as an operating point. Between points and T, the d aphragm closely abuts the magnet. It will be known that, in this specific case, the magnet has a considerable reserve of energy, and any loss attributable to the magnetic shunt circuit can be counterbalanced.
- reference numerals 51 and '52 designate the slit 13 between the spaces a and a and the slit 14 between the spaces a and a respectively.
- Numeral 53 designates viscosity of air behind the diaphragm 7.
- the magnetic driving force acting on the diaphragm is illustrated as at 54, and the diaphragm 7 is represented by 55.
- Numeral 56 designates the sound passage 12 for communication between the space at. and the eardrum.
- FIG. 5b shows also an electroacoustic equivalent circuit of a conventional electroacoustic transducer, wherein like numerals are used for the elements common to the circuit of FIG. 5a.
- the magnetic driving force Fm in the case of the present invention, is transmitted to the space before the eardrum through a resonance system having a degree of freedom of four against a degree of freedom of three in the case of the conventional device.
- the device of the invention as illustrated, is different from the conventional device in that it has an additional resonance circuit as enclosed by dotted lines in FIG. 5a and the resistance due to viscosity of the air layer behind the diaphragm also effectively operates.
- the increase in the degree of freedom of oscillation is effective to divide the peak resonance mainly appearing at a high frequency portion, thus a good frequency characteristic can be obtained.
- An electroacoustic transducer of small size comprising, a cylindrical frame, a pole piece disposed centrally in said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the as sembly of said pole piece, coil and permanent magnet, a plate of magnetic material disposed between said diaphragm and said cylindrical permanent magnet, a first space defined between said plate of magnetic material and said diaphragm, a second space defined by said plate of magnetic material, cylindrical frame and yoke, a small bore in said plate of magnetic material providing communication between said first space and second space, a space below said yoke, and a small bore in said yoke providing communication between said second space and said space below said yoke.
- An electroacoustic transducer of small size comprising, a cylindrical frame, a pole piece disposed centrally in said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the assembly of said pole piece, coil and permanent magnet, a plate of magnetic material and annular shape disposed between said diaphragm and said cylindrical permanent magnet, a first space defined between said annular plate of magnetic material and said diaphragm, a second space defined by said annular plate, cylindrical frame and yoke, a small bore in said annular plate of magnetic material providing communication between said first space and said second space, a space below said yoke, and a small bore in said yoke providing communication between said second space and said space below said yoke.
- An electroacoustic transducer of small size comprising, a cylindrical frame, a pole piece disposed centrally in said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the assembly of said pole piece, coil and permanent magnet, a plate of magnetic material disposed between said diaphragm and said cylindrical permanent magnet and taking-the form of a cup-like member which has a cylindrical portion depending from its annular portion so as to surround said permanent magnet with a small space therebetween, a first space defined between said cup-like member of magnetic material and said diaphragm, a second space defined by said cuplike member, cylindrical frame and yoke, a small bore in said cup-like member providing communication betwen said first space and said second space, a space below said yoke, and a small bore in said yoke providing communication between said second space and
- An electroacoustic transducer of small size comprising, a cylindrical frame, a pole piece disposed centrally in said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the assembly of said pole piece, coil and permanent magnet, a plate of magnetic material disposed between said diaphragm and said cylindrical permanent magnet, an outer casing for accommodating said pole piece, said coil, said permanent magnet, said diaphragm and said yoke, made of magnetic material so as to form a portion of a magnetic circuit, a first space defined between said plate of magnetic material and said diaphragm, a second space defined by said plate, cylindrical frame and yoke, a small bore in said plate of magnetic material providing communication between said first space and said second space, a space below said yoke, and a small bore in said yoke providing communication between said second space
- An electroacoustic transducer of small size comprising, a cylindrical frame, a pole piece disposed centrally in said cylindrical frame, a coil disposed concentrically about said pole piece, a cylindrical permanent magnet disposed concentrically about said coil, a diaphragm mounted on the assembly of said pole piece, coil and permanent magnet, a yoke disposed below the assembly of said pole piece, coil and permanent magnet, a plate of magnetic material and annular shape disposed between said diaphragm and said cylindrical permanent magnet, and outer casing for accommodating said pole piece, said coil, said permanent magnet, said diaphragm and said yoke, of magnetic material so as to form a portion of a magnetic circuit, said outer casing having an upper face, a shielding casing covering said upper face of said outer casing, a first space defined between said plate of magnetic material and said diaphragm, a second References Cited space defined 'by said plate, cylindrical frame and yoke, UNITED STATES PATENTS a small laor
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6065662 | 1962-10-15 | ||
JP6065762 | 1962-10-15 | ||
JP7738562 | 1962-12-18 | ||
JP1751263 | 1963-03-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3324253A true US3324253A (en) | 1967-06-06 |
Family
ID=27456791
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US316081A Expired - Lifetime US3324253A (en) | 1962-10-15 | 1963-10-14 | Small-sized electroacoustic transducers |
Country Status (4)
Country | Link |
---|---|
US (1) | US3324253A (de) |
DE (1) | DE1218520B (de) |
FR (1) | FR1380614A (de) |
GB (1) | GB1067273A (de) |
Cited By (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3584161A (en) * | 1968-12-06 | 1971-06-08 | Bell Telephone Labor Inc | Balanced magnetic transducer |
US4358642A (en) * | 1977-12-29 | 1982-11-09 | Kabushiki Kaisha Daini Seikosha | Electro-magnetic type electric acoustic transducer |
US4380689A (en) * | 1979-08-01 | 1983-04-19 | Vittorio Giannetti | Electroacoustic transducer for hearing aids |
US4578808A (en) * | 1981-12-30 | 1986-03-25 | Plessey Overseas Limited | Electro-acoustic transducers |
US5430803A (en) * | 1992-03-31 | 1995-07-04 | Soei Electric Co., Ltd. | Bifunctional earphone set |
EP0999722A2 (de) * | 1998-11-04 | 2000-05-10 | Matsushita Electric Industrial Co., Ltd. | Elektromagnetischer Wandler und tragbares Funksgerät |
USD435036S (en) * | 1999-11-17 | 2000-12-12 | Koss Corporation | Stereophone ear plug |
US6389145B2 (en) * | 1998-07-24 | 2002-05-14 | Agere Systems Guardian Corp. | Methods and apparatus for controlling the output of moving armature transducers |
US6411722B1 (en) | 2000-05-11 | 2002-06-25 | Dan Wolf | Earphone for an RF transmitting device |
US6751334B2 (en) * | 2000-03-09 | 2004-06-15 | Osseofon Ab | Electromagnetic vibrator |
US20050135651A1 (en) * | 2002-05-10 | 2005-06-23 | Bo Hakansson | Means at electromagnetic vibrator |
US20050155714A1 (en) * | 2004-01-15 | 2005-07-21 | Sonoco Development, Inc. | Dual-functioning mechanism for startup during winding of web material and for splicing during unwinding |
US20090064484A1 (en) * | 2004-09-17 | 2009-03-12 | Hakansson Bo E V | Method for the manufacturing of balanced transducers |
US7570777B1 (en) * | 2004-01-13 | 2009-08-04 | Step Labs, Inc. | Earset assembly |
US20160183006A1 (en) * | 2014-12-17 | 2016-06-23 | Taiyo Yuden Co., Ltd. | Piezoelectric speaker and electroacoustic transducer |
USD772204S1 (en) * | 2015-11-03 | 2016-11-22 | Cleer Gear Llc | Wireless earpiece with charging capsule |
USD777710S1 (en) * | 2015-07-22 | 2017-01-31 | Doppler Labs, Inc. | Ear piece |
USD781269S1 (en) * | 2015-02-06 | 2017-03-14 | Lg Electronics Inc. | Wireless headset |
USD800097S1 (en) * | 2016-05-05 | 2017-10-17 | Dongguan City Hele Electronic Co., Ltd. | Wireless earphone |
USD812042S1 (en) * | 2016-10-12 | 2018-03-06 | Shenzhen Zijieyuanzi Technology Co., ltd. | Wireless earset |
USD813848S1 (en) * | 2016-06-27 | 2018-03-27 | Dolby Laboratories Licensing Corporation | Ear piece |
USD817309S1 (en) * | 2016-12-22 | 2018-05-08 | Akg Acoustics Gmbh | Pair of headphones |
USD833420S1 (en) * | 2017-06-27 | 2018-11-13 | Akg Acoustics Gmbh | Headphone |
USD836614S1 (en) * | 2013-02-07 | 2018-12-25 | Decibullz Llc | Moldable earpiece |
US10194229B2 (en) | 2013-06-25 | 2019-01-29 | Google Llc | Headphones with adaptable fit |
USD844586S1 (en) | 2017-08-04 | 2019-04-02 | Google Llc | Audio assembly |
USD851072S1 (en) * | 2017-06-22 | 2019-06-11 | Fka Distributing Co., Llc | Earphone component |
USD858489S1 (en) * | 2018-01-04 | 2019-09-03 | Mpow Technology Co., Limited | Earphone |
USD867326S1 (en) | 2017-07-21 | 2019-11-19 | Google Llc | Wireless earbuds |
USD870708S1 (en) | 2017-12-28 | 2019-12-24 | Harman International Industries, Incorporated | Headphone |
USD871376S1 (en) * | 2019-03-02 | 2019-12-31 | Shenzhen Gu Ning Culture Co., Ltd. | Wireless earphone |
USD879075S1 (en) | 2018-07-11 | 2020-03-24 | Google Llc | Earbud stand assembly |
USD890696S1 (en) | 2017-07-21 | 2020-07-21 | Google Llc | Earbud charging case |
USD896781S1 (en) | 2017-08-04 | 2020-09-22 | Google Llc | Audio assembly |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE9106716U1 (de) * | 1991-05-31 | 1991-07-25 | Deutsche Airbus GmbH, 2000 Hamburg | Kopfhörer für eine Rettungs-Gegensprechanlage |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US2794862A (en) * | 1952-07-03 | 1957-06-04 | American Danish Oticon Corp | Electro-acoustic apparatus |
US3092693A (en) * | 1960-12-12 | 1963-06-04 | Nippon Telegraph & Telephone | Electromagnetic receiver |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE968712C (de) * | 1951-10-17 | 1958-03-20 | Gasaccumulator Svenska Ab | Beruehrungsmikrophon |
DE1719002U (de) * | 1955-12-06 | 1956-03-22 | Max Grundig | Magnetischer kleinsthoerer. |
NL259225A (de) * | 1960-06-08 |
-
1963
- 1963-10-14 US US316081A patent/US3324253A/en not_active Expired - Lifetime
- 1963-10-14 GB GB40447/63A patent/GB1067273A/en not_active Expired
- 1963-10-15 FR FR950643A patent/FR1380614A/fr not_active Expired
- 1963-10-15 DE DEM58553A patent/DE1218520B/de active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2794862A (en) * | 1952-07-03 | 1957-06-04 | American Danish Oticon Corp | Electro-acoustic apparatus |
US3092693A (en) * | 1960-12-12 | 1963-06-04 | Nippon Telegraph & Telephone | Electromagnetic receiver |
Cited By (45)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3584161A (en) * | 1968-12-06 | 1971-06-08 | Bell Telephone Labor Inc | Balanced magnetic transducer |
US4358642A (en) * | 1977-12-29 | 1982-11-09 | Kabushiki Kaisha Daini Seikosha | Electro-magnetic type electric acoustic transducer |
US4380689A (en) * | 1979-08-01 | 1983-04-19 | Vittorio Giannetti | Electroacoustic transducer for hearing aids |
US4578808A (en) * | 1981-12-30 | 1986-03-25 | Plessey Overseas Limited | Electro-acoustic transducers |
US5430803A (en) * | 1992-03-31 | 1995-07-04 | Soei Electric Co., Ltd. | Bifunctional earphone set |
US6389145B2 (en) * | 1998-07-24 | 2002-05-14 | Agere Systems Guardian Corp. | Methods and apparatus for controlling the output of moving armature transducers |
EP0999722A2 (de) * | 1998-11-04 | 2000-05-10 | Matsushita Electric Industrial Co., Ltd. | Elektromagnetischer Wandler und tragbares Funksgerät |
EP0999722A3 (de) * | 1998-11-04 | 2002-06-19 | Matsushita Electric Industrial Co., Ltd. | Elektromagnetischer Wandler und tragbares Funksgerät |
US6671383B2 (en) * | 1998-11-04 | 2003-12-30 | Matsushita Electric Industrial Co., Ltd. | Electromagnetic transducer and portable communication device |
USD435036S (en) * | 1999-11-17 | 2000-12-12 | Koss Corporation | Stereophone ear plug |
US6751334B2 (en) * | 2000-03-09 | 2004-06-15 | Osseofon Ab | Electromagnetic vibrator |
US6411722B1 (en) | 2000-05-11 | 2002-06-25 | Dan Wolf | Earphone for an RF transmitting device |
US20050135651A1 (en) * | 2002-05-10 | 2005-06-23 | Bo Hakansson | Means at electromagnetic vibrator |
US7570777B1 (en) * | 2004-01-13 | 2009-08-04 | Step Labs, Inc. | Earset assembly |
US20100061583A1 (en) * | 2004-01-13 | 2010-03-11 | Taenzer Jon C | Earset Assembly |
US7925038B2 (en) | 2004-01-13 | 2011-04-12 | Dolby Laboratories Licensing Corporation | Earset assembly |
US20050155714A1 (en) * | 2004-01-15 | 2005-07-21 | Sonoco Development, Inc. | Dual-functioning mechanism for startup during winding of web material and for splicing during unwinding |
US20090064484A1 (en) * | 2004-09-17 | 2009-03-12 | Hakansson Bo E V | Method for the manufacturing of balanced transducers |
US7827671B2 (en) * | 2006-04-12 | 2010-11-09 | Osseofon Ab | Method for the manufacturing of balanced transducers |
USD865721S1 (en) | 2013-02-07 | 2019-11-05 | Decibullz Llc | Moldable earpiece |
USD836614S1 (en) * | 2013-02-07 | 2018-12-25 | Decibullz Llc | Moldable earpiece |
US10506321B2 (en) | 2013-06-25 | 2019-12-10 | Google Llc | Headphones with adaptable fit |
US10194229B2 (en) | 2013-06-25 | 2019-01-29 | Google Llc | Headphones with adaptable fit |
US20160183006A1 (en) * | 2014-12-17 | 2016-06-23 | Taiyo Yuden Co., Ltd. | Piezoelectric speaker and electroacoustic transducer |
US9973857B2 (en) * | 2014-12-17 | 2018-05-15 | Taiyo Yuden Co., Ltd. | Piezoelectric speaker and electroacoustic transducer |
USD781269S1 (en) * | 2015-02-06 | 2017-03-14 | Lg Electronics Inc. | Wireless headset |
USD777710S1 (en) * | 2015-07-22 | 2017-01-31 | Doppler Labs, Inc. | Ear piece |
USD813205S1 (en) * | 2015-07-22 | 2018-03-20 | Dolby Laboratories Licensing Corporation | Ear piece |
USD772204S1 (en) * | 2015-11-03 | 2016-11-22 | Cleer Gear Llc | Wireless earpiece with charging capsule |
USD800097S1 (en) * | 2016-05-05 | 2017-10-17 | Dongguan City Hele Electronic Co., Ltd. | Wireless earphone |
USD813848S1 (en) * | 2016-06-27 | 2018-03-27 | Dolby Laboratories Licensing Corporation | Ear piece |
USD812042S1 (en) * | 2016-10-12 | 2018-03-06 | Shenzhen Zijieyuanzi Technology Co., ltd. | Wireless earset |
USD817309S1 (en) * | 2016-12-22 | 2018-05-08 | Akg Acoustics Gmbh | Pair of headphones |
USD851072S1 (en) * | 2017-06-22 | 2019-06-11 | Fka Distributing Co., Llc | Earphone component |
USD833420S1 (en) * | 2017-06-27 | 2018-11-13 | Akg Acoustics Gmbh | Headphone |
USD867326S1 (en) | 2017-07-21 | 2019-11-19 | Google Llc | Wireless earbuds |
USD890696S1 (en) | 2017-07-21 | 2020-07-21 | Google Llc | Earbud charging case |
USD921610S1 (en) | 2017-08-04 | 2021-06-08 | Google Llc | Audio assembly |
USD844586S1 (en) | 2017-08-04 | 2019-04-02 | Google Llc | Audio assembly |
USD896781S1 (en) | 2017-08-04 | 2020-09-22 | Google Llc | Audio assembly |
USD894152S1 (en) | 2017-08-04 | 2020-08-25 | Google Llc | Audio assembly |
USD870708S1 (en) | 2017-12-28 | 2019-12-24 | Harman International Industries, Incorporated | Headphone |
USD858489S1 (en) * | 2018-01-04 | 2019-09-03 | Mpow Technology Co., Limited | Earphone |
USD879075S1 (en) | 2018-07-11 | 2020-03-24 | Google Llc | Earbud stand assembly |
USD871376S1 (en) * | 2019-03-02 | 2019-12-31 | Shenzhen Gu Ning Culture Co., Ltd. | Wireless earphone |
Also Published As
Publication number | Publication date |
---|---|
DE1218520B (de) | 1966-06-08 |
FR1380614A (fr) | 1964-12-04 |
GB1067273A (en) | 1967-05-03 |
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