GB2076257A - Electro-acoustic transducers - Google Patents
Electro-acoustic transducers Download PDFInfo
- Publication number
- GB2076257A GB2076257A GB8118364A GB8118364A GB2076257A GB 2076257 A GB2076257 A GB 2076257A GB 8118364 A GB8118364 A GB 8118364A GB 8118364 A GB8118364 A GB 8118364A GB 2076257 A GB2076257 A GB 2076257A
- Authority
- GB
- United Kingdom
- Prior art keywords
- diaphragm
- lead wires
- voice coil
- electro
- adhesive
- 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.)
- Granted
Links
- 239000000853 adhesive Substances 0.000 claims abstract description 35
- 230000001070 adhesive effect Effects 0.000 claims abstract description 35
- 235000019589 hardness Nutrition 0.000 claims description 4
- 210000000188 diaphragm Anatomy 0.000 description 33
- 230000002093 peripheral effect Effects 0.000 description 12
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- YACLQRRMGMJLJV-UHFFFAOYSA-N chloroprene Chemical compound ClC(=C)C=C YACLQRRMGMJLJV-UHFFFAOYSA-N 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/06—Arranging circuit leads; Relieving strain on circuit leads
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
- H04R9/04—Construction, mounting, or centering of coil
- H04R9/045—Mounting
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
- Headphones And Earphones (AREA)
Abstract
An electro-acoustic transducer of dynamic type, particularly a small loudspeaker or microphone, such as a loudspeaker for use in headphones, comprises a magnetic circuit 26 including an air gap 34, a diaphragm 20 having a voice coil 36 disposed in the air gap 34, and lead wires 38 for the voice coil 36, the lead wires 38 extending substantially tangentially from the voice coil 36 and being bonded to the diaphragm 20 by two different kinds of adhesive, a relatively hard adhesive 44 being used near the voice coil 36 and a relatively sort adhesive 46 being used near the periphery of the diaphragm 20. <IMAGE>
Description
1 GB2076257A 1 SPECIFICATION ,, Efectro-acoustic transducers This
invention relates to electro-acoustic trans- ducers, and more particularly, but not exclusively, to relatively small loudspeakers for use in headphones. The invention is also applicable to loudspeakers of other sizes and for other purposes, and also to microphones.
Generally, a relatively small electro-acoustic transducer such as a loudspeaker for use in headphones includes a magnetic circuit and a diaphragm which comprises a dome-shaped central portion and a ring-shaped peripheral portion to be fixed to a frame. A voice coil is fixed to the diaphragm where the central and peripheral portions of the diaphragm meet, and is disposed in an air gap formed in the magnetic circuit.
Lead wires for the voice coil extend radially along the undersurface of the peripheral portion of the diaphragm and are bonded thereto by a suitable adhesive. Beyond the adhesive, unsupported portions of the lead wires are bent at right angles at or near the periphery of the diaphragm in order to be connected to terminals provided on an outside surface of the frame.
When the diaphragm vibrates with large amplitude, it is not uncommon for the lead wires to snap. This is because the portions of -the lead wires fixed to the peripheral portion of the diaphragm move together with the diaphragm, but the bent portions of the lead wires are not supported and moreover are bent at right angles, so that after a time the wire suffers from metal fatigue and may be come brittle and snap. The radial disposition of the lead wires also causes problems as they contact the peripheral portion of the dia phragm when the diaphragm vibrates with large amplitude, and this generates a noise.
According to the present invention there is provided an electro-acoustic transducer com prising:
a mounting member; a magnetic circuit secured to said mounting member and having an air gap; a diaphragm having an edge portion fixed to 115 said mounting member; a cylindrical voice coil mounted on said dia phragm and extending into said air gap of said magnetic circuit; lead wires extending from said voice coil in 120 the direction of the edge portion of said diaphragm along the surface of said dia phragm; and adhesives of two different hardnesses bonding said lead wires to said diaphragm, a relatively hard adhesive being used for the portions of said lead wires nearer the voice coil and a relative soft adhesive being used for portions of said lead wires nearer the edge portion of said diaphragm.
The invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 shows a cross-sectionai view of an embodiment of electro-acoustic transducer according to the invention; Figure 2 shows a bottom plan view and in particular a voice coil and lead wires of the transducer of Fig. 1; Figure 3 shows another bottom plan view of the transducer of Fig. 1; and Figure 4 shows a bottom plan view of another embodiment of electroacoustic transducer according to the invention.
The embodiments to be described are smallsized electro-acoustic transducers forming loudspeakers suitable for use in headphones.
The transducer of Fig. 1, to which reference is now made, comprises a small-sized dia- phragm 20 formed by a film of plastics material, a magnetic circuit 26 and a mounting member formed by a moulded frame 22 of plastics material to which the magnetic circuit 26 and the diaphragm 20 are secured. The diaphragm 20 comprises a dome-shaped central portion 20a and a ring- shaped peripheral portion 20b contiguous to the central portion 20a, an edge portion 20c of the peripheral portion 20b being fixed to the frame 22 through a suitable ring 24.
The magnetic circuit 26 comprises a circular plate 28, a permanent magnet 30 and a yoke 32, an air gap 34 being formed between the plate 28 and the yoke 32. A cylindrical voice coil 36 is secured to the boundary region between the central portion 20a and the portion 20b of the diaphragm 20 by a suitable adhesive, and is disposed so as to extend into the air gap 34. The voice coil 36 does not have a bobbin.
As also seen in Fig. 2, lead wires 38 for the voice coil 36 have tangential portions 38a which extend substantially tangentially from the voice coil 36 and which then merge into circular arc portions 38b which extend along the peripheral portion 20b of the diaphragm 20 close to the ring 24, The circular arc portions 38b then bend away from the diaphragm 20 as shown in Fig. 1, to extend through an opening 40 formed in the frame 22 and are connected to terminals 47 and 48 which are mounted on an insulating plate 42 mounted on the outer surface of the frame 22 as also seen in Fig.3.
With this embodiment, the tangential portions 38a of the lead wires 38 are bonded to the undersurface of the diaphragm 20 by an adhesive 44 which is relatively hard. The adhesive 44 may for example be a rubber system adhesive, such as a solvent type of chloroprene, for example DB- 4378, this being a Trade Name of D13 Bond Corporation. The circular arc portions 38b of the lead wires 38 are bonded to the diaphragm 20 by an adhe- sive 46 which is relatively soft. This may for GB 2 076 257A 2 example be an acrylic system adhesive, for example, SC-717, this being a Trade Name of Sony Chemical Corporation. Moreover, the lead. wires 38 are located in the opening 40 by an adhesive 45 which may be the same acrylic system adhesive just mentioned. Finally, the end portions of the lead wires 38 nearest to the terminals 47 and 48 may be bonded by an epoxy system adhesive 50.
Thus in this embodiment the lead wires 38 of the voice coil 36 are bonded to the diaphragm 20 by two different kinds of adhesive, having different hardnesses, the relatively hard adhesive being nearer the voice coil 36 and the relatively soft adhesive being nearer ihe edge portion 20c of the diaphragm 20. This means that the portions of the lead wires 38 nearer to the voice coil 36, that is the tangential portions 38a vibrate together with the voice coil 36 as one body. Hpwever, the circular arc portions 38b of the lead wires 38, that is the portions near the edge portion 20c of the diaphragm 20 vibrate with the voice coil 36 as one body when the voice coil 36 vibrates with only a comparatively small amplitude, but if the voice coil 36 vibrates with relatively large amplitude, the circular arc portions 38b of the lead wires 38 are able to move relative to the adhesive 46, due to the softness of the adhesive 46. The same effect tends to occur if a large external force is applied to the peripheral portion 20b of the diaphragm 20. This means that in such cases the forces applied to the lead wires 38 tend to be absorbed in the adhesives, particularly the adhesive 46, and this reduces forces acting in particular on the bent portions 38c of the lead wires 38, and reduces the tendency for the lead wires 38 to snap.
In the modified embodiment shown in Fig. 4, to which reference is now made, lead wires 38 extend substantially tangentially from a voice coil 36, but form a circular arc and so take a relatively long path between the voice coil 36 and the outer edge of the peripheral portion 20b of the diaphragm 20. Portions of the lead wires 38 nearer the voice coil 36 are bonded to the diaphragm 20 by a relatively hard adhesive 44 such as a rubber system adhesive, and portions of the lead wires 38 further from the voice coil 36 and nearer to the outer edge of the peripheral portion 20b of the diaphragm 20 are bonded to the dia'phragm 20 by a relatively soft adhesive 46, such as an acrylic system adhesive. As in the first embodiment described above, therefore, the tendency for the lead wires 38 to be subjected to excessive forces and hence to snap is reduced.
Thus in embodiments of the invention the lead wires of a voice coil extend from the voice coil to a peripheral portion of the diaphiragm along a circular arc, so as to take a long path relative to the radial path used in the prior art. This reduces the forces acting on the lead wires and reduces the possibility of the lead wires snapping. Also, two different kinds of adhesive of different hardnesses may be used for securing the lead wires, and this also contributes to reducing the risk of the lead wires snapping. This is particularly effer,tive where the lead wires extend along the periphery of the diaphragm and are secured by a relatively soft adhesive, as described with reference to Fig. 2. Moreover, the provision of a relatively soft adhesive, such as an acrylic system adhesive, has a damping effect on the lead wires and reduces the possibility of unwanted noise being generated by contact be- tween the lead wires and the diaphragm.
Although the embodiments described are small-sized loudspeakers, the invention can also be applied to loudspeakers of other sizes and also to microphones of dynamic type.
'Attention is drawn to our copending application no. 8040668 (serial no. 2067378) on which the present application is divided and relating to similar subject matter.
Claims (5)
1. An electro-acoustic transducer comprising: a mounting member; a magnetic circuit secured to said mounting member and having an air gap; a diaphragm having an edge portion fixed to said mounting member; a cylindrical voice coil mounted on said diaphragm and extending into said air gap of said magnetic circuit; lead wires extending from said voice coil in the direction of the edge portion of said diaphragm along the surface of said diaphragm; and adhesives of two different hardnesses bonding said lead wires to said diaphragm, a relatively hard adhesive being used for the portions of said lead wires nearer the voice coil and a relative soft adhesive being used for portions of said lead wires nearer the edge portion of said diaphragm.
2. An electro-acoustic transducer accord-ing to claim 1 wherein said lead wires extend substantially tangentially from said voice coil.
3. An electro-acoustic transducer accord-.
ing to claim 2 wherein said lead wires include circular arc portions extending along part of the periphery of said diaphragm. 1k
4. An electro-acoustic transducer accord- ing to claim 1 and substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.
5. - An electro-acoustic transducer according to claim 1 and substantially as hereinbe- fore described with reference to Figs. 1 to 3 as modified by Fig. 4 of the accompanying drawings.
%k 4 11 3 t.
11 GB 2 076 257A 3 Printed for Her Majesty's Stationery Office by Burgess Et Son (Abingdon) Ltdl 981. Published at The Patent Office, 25 Southampton Buildings, London, WC2A IAY, from which copies may be obtained,
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54172668A JPS6028200B2 (en) | 1979-12-31 | 1979-12-31 | electroacoustic transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2076257A true GB2076257A (en) | 1981-11-25 |
| GB2076257B GB2076257B (en) | 1983-11-30 |
Family
ID=15946149
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8118364A Expired GB2076257B (en) | 1979-12-31 | 1980-12-18 | Electro-acoustic transducers |
| GB8040668A Expired GB2067378B (en) | 1979-12-31 | 1980-12-18 | Electro-acoustic transducers |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8040668A Expired GB2067378B (en) | 1979-12-31 | 1980-12-18 | Electro-acoustic transducers |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS6028200B2 (en) |
| AT (1) | AT369940B (en) |
| AU (1) | AU540983B2 (en) |
| BR (1) | BR8008627A (en) |
| CA (1) | CA1160732A (en) |
| DE (1) | DE3048779A1 (en) |
| ES (1) | ES8204902A1 (en) |
| FR (1) | FR2472899B1 (en) |
| GB (2) | GB2076257B (en) |
| IT (1) | IT1146224B (en) |
| NL (1) | NL191225C (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58173998U (en) * | 1982-05-14 | 1983-11-21 | シャープ株式会社 | electrodynamic speaker |
| JPS5920797U (en) * | 1982-07-26 | 1984-02-08 | シャープ株式会社 | electrodynamic speaker |
| JPS62121900U (en) * | 1986-01-24 | 1987-08-03 | ||
| JP2674777B2 (en) * | 1988-04-15 | 1997-11-12 | 松下電工株式会社 | Scanner for light beam scanning |
| NO169210C (en) * | 1989-07-06 | 1992-05-20 | Nha As | ELECTRODYNAMIC AUDIO FOR HEARING DEVICE. |
| DE4243308C2 (en) * | 1992-12-21 | 1996-08-22 | Sennheiser Electronic | Dynamic electro-acoustic transducer, especially headphones |
| DE4434630A1 (en) * | 1994-09-28 | 1996-04-04 | Nokia Deutschland Gmbh | UV adhesive for fixing coated wires in a moving coil of loudspeaker |
| DE19630169A1 (en) * | 1996-07-26 | 1998-01-29 | Nokia Deutschland Gmbh | Voice coil contact arrangement |
| WO2003032505A2 (en) * | 2001-10-04 | 2003-04-17 | Koninklijke Philips Electronics N.V. | Electroacoustic transducer having a moving coil and having movable holding elements for the connecting leads of the moving coil |
| JP4159408B2 (en) | 2003-05-26 | 2008-10-01 | パイオニア株式会社 | Speaker |
| ITBO20110356A1 (en) | 2011-06-21 | 2012-12-22 | Gd Spa | WHEELING UNIT OF A WRAPPING MATERIAL TAPE |
| DE102015201940A1 (en) * | 2015-02-04 | 2016-08-04 | Sennheiser Electronic Gmbh & Co. Kg | Electrodynamic transducer |
| JP2019161542A (en) * | 2018-03-15 | 2019-09-19 | オンキヨー株式会社 | Diaphragm, speaker unit including the same, headphone, earphone, and method of manufacturing diaphragm |
| JPWO2020183865A1 (en) * | 2019-03-13 | 2021-10-21 | 株式会社デンソーエレクトロニクス | Sounder |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB776280A (en) * | 1954-05-26 | 1957-06-05 | Cole E K Ltd | Improvements in or relating to moving coil loudspeakers and microphones |
| US3032615A (en) * | 1960-02-02 | 1962-05-01 | Rca Corp | Acoustic devices |
| US3284581A (en) * | 1963-06-03 | 1966-11-08 | Columbia Broadcasting Syst Inc | Loud speaker construction |
| DE1907850U (en) * | 1964-06-05 | 1965-01-07 | Blaupunkt Werke Gmbh | LOUDSPEAKER WITH LEADS TO A VOICE COIL. |
| NL6712007A (en) * | 1967-08-31 | 1969-03-04 | ||
| AU414741B2 (en) * | 1968-06-26 | 1971-07-09 | Girling Limited | Improvements in vehicle braking systems |
| DE1951162A1 (en) * | 1969-10-10 | 1971-04-22 | Witt Horst C | Work platform for the construction of chimneys or the like. |
-
1979
- 1979-12-31 JP JP54172668A patent/JPS6028200B2/en not_active Expired
-
1980
- 1980-12-18 AU AU65526/80A patent/AU540983B2/en not_active Ceased
- 1980-12-18 GB GB8118364A patent/GB2076257B/en not_active Expired
- 1980-12-18 GB GB8040668A patent/GB2067378B/en not_active Expired
- 1980-12-22 NL NL8006984A patent/NL191225C/en not_active IP Right Cessation
- 1980-12-23 DE DE19803048779 patent/DE3048779A1/en active Granted
- 1980-12-23 CA CA000367435A patent/CA1160732A/en not_active Expired
- 1980-12-23 AT AT0630380A patent/AT369940B/en not_active IP Right Cessation
- 1980-12-23 FR FR8027358A patent/FR2472899B1/en not_active Expired
- 1980-12-29 IT IT50471/80A patent/IT1146224B/en active
- 1980-12-30 BR BR8008627A patent/BR8008627A/en unknown
- 1980-12-30 ES ES498231A patent/ES8204902A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NL191225B (en) | 1994-10-17 |
| FR2472899A1 (en) | 1981-07-03 |
| JPS6028200B2 (en) | 1985-07-03 |
| NL191225C (en) | 1995-03-16 |
| DE3048779A1 (en) | 1981-09-17 |
| IT1146224B (en) | 1986-11-12 |
| BR8008627A (en) | 1981-07-28 |
| ATA630380A (en) | 1982-06-15 |
| CA1160732A (en) | 1984-01-17 |
| AT369940B (en) | 1983-02-10 |
| FR2472899B1 (en) | 1985-09-13 |
| GB2076257B (en) | 1983-11-30 |
| GB2067378A (en) | 1981-07-22 |
| ES498231A0 (en) | 1982-05-01 |
| JPS5698097A (en) | 1981-08-07 |
| DE3048779C2 (en) | 1989-01-12 |
| IT8050471A0 (en) | 1980-12-29 |
| ES8204902A1 (en) | 1982-05-01 |
| AU6552680A (en) | 1981-07-09 |
| GB2067378B (en) | 1983-12-21 |
| NL8006984A (en) | 1981-08-03 |
| AU540983B2 (en) | 1984-12-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20001217 |