EP0077615A1 - Electret microphone shield - Google Patents

Electret microphone shield Download PDF

Info

Publication number
EP0077615A1
EP0077615A1 EP82305196A EP82305196A EP0077615A1 EP 0077615 A1 EP0077615 A1 EP 0077615A1 EP 82305196 A EP82305196 A EP 82305196A EP 82305196 A EP82305196 A EP 82305196A EP 0077615 A1 EP0077615 A1 EP 0077615A1
Authority
EP
European Patent Office
Prior art keywords
electret
casing
electret microphone
microphone
further characterised
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
Application number
EP82305196A
Other languages
German (de)
French (fr)
Other versions
EP0077615B1 (en
Inventor
Guy John Chaput
Edward Matthew Sich
Beverley William Thomas Gumb
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nortel Networks Ltd
Original Assignee
Northern Telecom Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Northern Telecom Ltd filed Critical Northern Telecom Ltd
Publication of EP0077615A1 publication Critical patent/EP0077615A1/en
Application granted granted Critical
Publication of EP0077615B1 publication Critical patent/EP0077615B1/en
Expired legal-status Critical Current

Links

Images

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
    • H04R1/08—Mouthpieces; Microphones; Attachments therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/01—Electrostatic transducers characterised by the use of electrets
    • H04R19/016—Electrostatic transducers characterised by the use of electrets for microphones

Definitions

  • This invention relates to electret microphones particularly for use in telephones.
  • Telephone electret microphones need to be shielded from electromagnetic interference to which the microphone is subjected in normal use. Such fields existing in the home, for example, are radiated from nearby television and radio transmitters and from electric motors.
  • the microphone,components are surrounded by, and the electret element shielded by, an aluminum casing.
  • One or more circular holes in the surface of the casing allows transmission of acoustic waves to the electret element.
  • the electret element is subjected to a distorted electric field due to body capacitance.
  • the output from the electret element is taken to an amplifier and then to a balanced line, balanced line transmission being used to compensate for interference occurring in the transmission path.
  • unbalance produced by a distorted field at the electret element will not be compensated and is seen as a component of the acoustic signal. Consequently, shielding of all interference at the microphone, including that produced by body capacitance, is necessary.
  • a known electret microphone used in a telephone consists of the following components.
  • the top component which, in use, is located nearest the speaker's mouth, is one part of a two-part aluminum casing.
  • the casing has a hole through its center to allow passage of acoustic waves.
  • Beneath this casing part is a moisture barrier which is normally a thin film of plastic material such as Mylar (Registered Trade Mark) which is pressed into sealing engagement with the top part of the casing.
  • Mylar Registered Trade Mark
  • Below the moisture barrier and a * compressible mounting ring for the moisture barrier lies the electret element which, together with associated electrical components, seats within a second part of the aluminum casing.
  • the thin, acoustically transparent moisture barrier be a conducting component and that said component be situated such that it electrically contacts the electret microphone casing or other grounded or fixed potential body.
  • the component comprises a substrate plastic film, the film having a conductive coating deposited thereon.
  • the microphone illustrated has a top ferrule or casing part 10 having a passage 11.
  • the ferrule is made of aluminum. It has an upper ridge 12 which can engage an internal threaded part of a telephone handset housing (not shown).
  • An upwardly pressed annular portion 14 accommodates and centers a sealing washer 16.
  • the sealing washer 16 presses a combined moisture barrier and shielding element 18 into the recessed portion 14.
  • the element 18 has an upper conducting surface 20.
  • the element is manufactured by vacuum-depositing a thin layer of aluminum onto a plastic film 21, such as Mylar of a thickness of 10 um. The thickness and flexibility of the element 18 is such that it is rendered transparent to acoustic vibrations of between 10 Hz and 4 KHz.
  • the sealing washer 16 acts to tension the element 18. If the element is improperly mounted, then there is a risk of its affecting the voice frequency vibration transmitted by it.
  • the transducer element 22 comprises a top frame 24 which clamps a piece of electret foil 26 against a bottom plate 28 by means of chips 29.
  • the foil has a metallic top surface and a bottom layer which has the property of being able to store a charge for extended periods.
  • the structure of the electret is well-known.
  • the charge storage face is separated from a conducting layer 30 on the back plate 28 by 50 microns thick strips of dielectric film 32.
  • the plate 28 in the region of the conducting layer is formed with holes 34 to permit the electret to vibrate in response to acoustic waves passing into the microphone.
  • the potential difference between the conducting layer 30 and the conducting surface of the electret varies to give an electric analog of the voice frequency vibration.
  • a printed conductor on board 36 which has wire leads 37 bonded to the electrical surfaces of the electret element 22, the varying electret voltage is taken to a field effect transistor (not shown) mounted on the reverse surface of the board.
  • the field effect transistor projects into a chamber 40 which is formed in a bottom part 42 of the aluminum casing.
  • the chamber size is chosen to optimize vibration of the electret foil 26.
  • Contacts (not shown) are also formed on the reverse surface of the board 36 and communicate electrically with the circuit formed on the board upper face. The contacts project through a passage 46 in the casing part 42.
  • a second seal 48 which surrounds the contacts 44 protects the inside of the microphone from adverse environmental conditions.
  • the casing comprising ferrule 10 and bottom part 42 is grounded via one of the conductors on board 36, and so, consequently, is the top surface of the element 18.
  • the element 18 thus functions to seal the microphone from moisture and gaseous contaminants and acts also to make the electromagnetic shield around the electret element complete.
  • the primary affect of this additional shielding part is in reducing the interference of that electric field produced by body capacitance which would otherwise affect the electret microphone output transmitted to a balanced line.
  • the element 18 could, instead, be a single layer of conducting foil.
  • Aluminum is particularly preferred as a conducting coating for the element 18 firstly, since it is easily vacuum-deposited on a plastic substrate, secondly, since the ferrule is also made of aluminum and therefore would not form an electric cell with the coating when damp, and lastly, since aluminum is a good conductor.
  • other conductors such as copper or zinc may be preferred, or the element may alternatively be composed of a carbon loaded plastic.
  • the top surface of the 5 element 18 is made conducting and that surface contacts the grounded ferrule 10. In other arrangements it may be preferred not to ground the casing around the electret in which case the conductive coating on the element 18 can be deposited on whichever surface of the element is made to contact a grounded or other fixed potential body.
  • the conductive coating extends over the full surface area of the element 18 so as to completely surround the transducer element 22 with an electromagnetic shield.
  • a conductive coating can be deposited on both sides of the element 18 in order to facilitate assembly.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Telephone Set Structure (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)

Abstract

An electret microphone has a metal shield around it in order to guard against electromagnetic interference. Acoustic waves reach the electret element through a passage in the shield. The electret response is undesirably affected by an electric field produced by body capacitance when the microphone is brought close to a user's mouth. To overcome this effect, the microphone has a conductive film, transparent to acoustic waves, positioned between the passage and the electret element, the film contacting a grounded part of the casing. The conductive film can form an integral part of a microphone moisture barrier.

Description

  • This invention relates to electret microphones particularly for use in telephones.
  • Telephone electret microphones need to be shielded from electromagnetic interference to which the microphone is subjected in normal use. Such fields existing in the home, for example, are radiated from nearby television and radio transmitters and from electric motors. In a known telephone electret microphone design, the microphone,components are surrounded by, and the electret element shielded by, an aluminum casing. One or more circular holes in the surface of the casing allows transmission of acoustic waves to the electret element. Unfortunately, as a telephone user brings his face towards the hole, the electret element is subjected to a distorted electric field due to body capacitance. Normally, the output from the electret element is taken to an amplifier and then to a balanced line, balanced line transmission being used to compensate for interference occurring in the transmission path. However, unbalance produced by a distorted field at the electret element will not be compensated and is seen as a component of the acoustic signal. Consequently, shielding of all interference at the microphone, including that produced by body capacitance, is necessary.
  • A known electret microphone used in a telephone consists of the following components. The top component, which, in use, is located nearest the speaker's mouth, is one part of a two-part aluminum casing. The casing has a hole through its center to allow passage of acoustic waves. Beneath this casing part is a moisture barrier which is normally a thin film of plastic material such as Mylar (Registered Trade Mark) which is pressed into sealing engagement with the top part of the casing. Below the moisture barrier and a* compressible mounting ring for the moisture barrier, lies the electret element which, together with associated electrical components, seats within a second part of the aluminum casing.
  • By the invention, it is proposed that the thin, acoustically transparent moisture barrier be a conducting component and that said component be situated such that it electrically contacts the electret microphone casing or other grounded or fixed potential body.
  • Preferably the component comprises a substrate plastic film, the film having a conductive coating deposited thereon.
  • An embodiment of the invention will now be described by way of example with reference to the accompanying exploded view of an electret microphone.
  • Referring in detail to the drawing, the microphone illustrated has a top ferrule or casing part 10 having a passage 11. The ferrule is made of aluminum. It has an upper ridge 12 which can engage an internal threaded part of a telephone handset housing (not shown). An upwardly pressed annular portion 14 accommodates and centers a sealing washer 16. On assembly, the sealing washer 16 presses a combined moisture barrier and shielding element 18 into the recessed portion 14. The element 18 has an upper conducting surface 20. The element is manufactured by vacuum-depositing a thin layer of aluminum onto a plastic film 21, such as Mylar of a thickness of 10 um. The thickness and flexibility of the element 18 is such that it is rendered transparent to acoustic vibrations of between 10 Hz and 4 KHz. The sealing washer 16 acts to tension the element 18. If the element is improperly mounted, then there is a risk of its affecting the voice frequency vibration transmitted by it.
  • Below the flexible sealing washer 18 and tight against it is a transducer element 22. Basically the transducer element comprises a top frame 24 which clamps a piece of electret foil 26 against a bottom plate 28 by means of chips 29. The foil has a metallic top surface and a bottom layer which has the property of being able to store a charge for extended periods. The structure of the electret is well-known. The charge storage face is separated from a conducting layer 30 on the back plate 28 by 50 microns thick strips of dielectric film 32. The plate 28 in the region of the conducting layer is formed with holes 34 to permit the electret to vibrate in response to acoustic waves passing into the microphone. Because the charge stored in the bottom layer of the electret foil is invariable, then as it vibrates, the potential difference between the conducting layer 30 and the conducting surface of the electret varies to give an electric analog of the voice frequency vibration. By means of a printed conductor on board 36 which has wire leads 37 bonded to the electrical surfaces of the electret element 22, the varying electret voltage is taken to a field effect transistor (not shown) mounted on the reverse surface of the board. The field effect transistor projects into a chamber 40 which is formed in a bottom part 42 of the aluminum casing. The chamber size is chosen to optimize vibration of the electret foil 26. Contacts (not shown) are also formed on the reverse surface of the board 36 and communicate electrically with the circuit formed on the board upper face. The contacts project through a passage 46 in the casing part 42. A second seal 48 which surrounds the contacts 44 protects the inside of the microphone from adverse environmental conditions.
  • In use, the casing comprising ferrule 10 and bottom part 42 is grounded via one of the conductors on board 36, and so, consequently, is the top surface of the element 18. The element 18 thus functions to seal the microphone from moisture and gaseous contaminants and acts also to make the electromagnetic shield around the electret element complete. As previously indicated, the primary affect of this additional shielding part is in reducing the interference of that electric field produced by body capacitance which would otherwise affect the electret microphone output transmitted to a balanced line.
  • The combination of a plastic substrate and a thin deposited coating for the sealing element 18 is viewed as being an optimal but non-limiting construction. Thus the element 18 could, instead, be a single layer of conducting foil. However, it would be difficult to manufacture such a thin foil of, say, aluminum having the required transparency to voice frequency vibration, while retaining sufficient strength to mechanically protect the electret. Aluminum is particularly preferred as a conducting coating for the element 18 firstly, since it is easily vacuum-deposited on a plastic substrate, secondly, since the ferrule is also made of aluminum and therefore would not form an electric cell with the coating when damp, and lastly, since aluminum is a good conductor. However, it is appreciated that in other circumstances other conductors such as copper or zinc may be preferred, or the element may alternatively be composed of a carbon loaded plastic.
  • . In the embodiment shown, the top surface of the 5 element 18 is made conducting and that surface contacts the grounded ferrule 10. In other arrangements it may be preferred not to ground the casing around the electret in which case the conductive coating on the element 18 can be deposited on whichever surface of the element is made to contact a grounded or other fixed potential body.
  • In the embodiment described, the conductive coating extends over the full surface area of the element 18 so as to completely surround the transducer element 22 with an electromagnetic shield. However, in other circumstances, it may be preferred to limit the extent of the conducting coating on the element 18 to a central or marginal region vertically aligned with the central hole through the ferrule 10.
  • A conductive coating can be deposited on both sides of the element 18 in order to facilitate assembly.

Claims (10)

1. An electret microphone comprising a casing and an electret element within the casing for producing an electrical signal corresponding to acoustic vibration passing into the casing through a passage therein, characterised in that a conducting element (18) blocks at least a part of said passage (11), the conducting element (18) transparent to said acoustic vibration and electrically contacting a fixed potential body (10) whereby to fix the potential of the conducting element (18).
- 2. An electret microphone as claimed in claim 1, further characterised in that the conducting element comprises a conductive layer (20) deposited on a substrate (21).
3. An electret microphone as claimed in claim 2 further characterised in that the conductive layer (20) is deposited on opposed sides of a lamellar substrate (21).
4. An electret microphone as claimed in claim 2, further characterised in that the substrate (21) is a film of flexible plastics.
5. An electret microphone as claimed in claim 4, further characterised in that the element (21) comprising said plastics substrate supporting said deposited conducting layer is moisture- impermeable.
6. An electret microphone as claimed in claim 5, further characterised in that a sealing member (16) presses the combination of said substrate (21) and the conducting layer (20) into engagement with an inside surface of the casing (10).
7. An electret microphone as claimed in claim 1, further characterised the casing in that (10) is conducting and is grounded, said conducting element (18) electrically contacting an inner surface of the casing (10).
8. An electret microphone as claimed in claim 7, further characterised in that both the conducting element (18) and the casing (10) are made of aluminum.
9. An electret microphone as claimed in claim 1, further characterised in that the conducting element (18) is composed of a conductor loaded plastic.
10. An electret microphone as claimed in claim 9, further characterised in that the conductor is carbon.
EP82305196A 1981-10-19 1982-09-30 Electret microphone shield Expired EP0077615B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA000388183A CA1165859A (en) 1981-10-19 1981-10-19 Electret microphone shield
CA388183 1981-10-19

Publications (2)

Publication Number Publication Date
EP0077615A1 true EP0077615A1 (en) 1983-04-27
EP0077615B1 EP0077615B1 (en) 1986-04-30

Family

ID=4121192

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82305196A Expired EP0077615B1 (en) 1981-10-19 1982-09-30 Electret microphone shield

Country Status (7)

Country Link
EP (1) EP0077615B1 (en)
JP (1) JPS5881000A (en)
KR (1) KR880000963B1 (en)
CA (1) CA1165859A (en)
DE (1) DE3270879D1 (en)
DK (1) DK153619C (en)
IE (1) IE53590B1 (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2218298A (en) * 1987-11-28 1989-11-08 Anthony David Heyes An ultra-sonic pulse-echo ranging device
GB2324222A (en) * 1997-04-11 1998-10-14 Sennheiser Electronic Sweat-proof capacitor microphone
WO2002045463A2 (en) * 2000-11-28 2002-06-06 Knowles Electronics, Llc Miniature silicon condenser microphone and method for producing same
US6781231B2 (en) 2002-09-10 2004-08-24 Knowles Electronics Llc Microelectromechanical system package with environmental and interference shield
EP1883271A1 (en) * 2006-07-27 2008-01-30 Star Micronics Co., Ltd. Microphone case and condenser microphone
US7381589B2 (en) 2000-11-28 2008-06-03 Knowles Electronics, Llc Silicon condenser microphone and manufacturing method
US7439616B2 (en) 2000-11-28 2008-10-21 Knowles Electronics, Llc Miniature silicon condenser microphone
US7483542B2 (en) * 2004-08-31 2009-01-27 Kabushiki Kaisha Audio-Technica Condenser microphone
US7894622B2 (en) 2006-10-13 2011-02-22 Merry Electronics Co., Ltd. Microphone
US8617934B1 (en) 2000-11-28 2013-12-31 Knowles Electronics, Llc Methods of manufacture of top port multi-part surface mount silicon condenser microphone packages
US9078063B2 (en) 2012-08-10 2015-07-07 Knowles Electronics, Llc Microphone assembly with barrier to prevent contaminant infiltration
US9374643B2 (en) 2011-11-04 2016-06-21 Knowles Electronics, Llc Embedded dielectric as a barrier in an acoustic device and method of manufacture
US9794661B2 (en) 2015-08-07 2017-10-17 Knowles Electronics, Llc Ingress protection for reducing particle infiltration into acoustic chamber of a MEMS microphone package

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005008511B4 (en) 2005-02-24 2019-09-12 Tdk Corporation MEMS microphone
DE102005008512B4 (en) 2005-02-24 2016-06-23 Epcos Ag Electrical module with a MEMS microphone
DE102005053765B4 (en) 2005-11-10 2016-04-14 Epcos Ag MEMS package and method of manufacture
DE102005053767B4 (en) 2005-11-10 2014-10-30 Epcos Ag MEMS microphone, method of manufacture and method of installation

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3778561A (en) * 1972-06-21 1973-12-11 Bell Canada Northern Electric Electret microphone
US3787642A (en) * 1971-09-27 1974-01-22 Gte Automatic Electric Lab Inc Electrostatic transducer having resilient electrode
US3942029A (en) * 1973-07-23 1976-03-02 Sony Corporation Electrostatic transducer
US4188513A (en) * 1978-11-03 1980-02-12 Northern Telecom Limited Electret microphone with simplified electrical connections by printed circuit board mounting

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5717013Y2 (en) * 1977-07-11 1982-04-09

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3787642A (en) * 1971-09-27 1974-01-22 Gte Automatic Electric Lab Inc Electrostatic transducer having resilient electrode
US3778561A (en) * 1972-06-21 1973-12-11 Bell Canada Northern Electric Electret microphone
US3942029A (en) * 1973-07-23 1976-03-02 Sony Corporation Electrostatic transducer
US4188513A (en) * 1978-11-03 1980-02-12 Northern Telecom Limited Electret microphone with simplified electrical connections by printed circuit board mounting

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
THE BELL SYSTEM JOURNAL, vol. 58, no. 7, September 1979, pages 1557-1577, New York (USA); *

Cited By (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2218298A (en) * 1987-11-28 1989-11-08 Anthony David Heyes An ultra-sonic pulse-echo ranging device
GB2324222A (en) * 1997-04-11 1998-10-14 Sennheiser Electronic Sweat-proof capacitor microphone
US6111966A (en) * 1997-04-11 2000-08-29 Staat; Raimund Capacitor microphone
GB2324222B (en) * 1997-04-11 2001-10-17 Sennheiser Electronic A capacitor microphone
US8629551B1 (en) 2000-11-28 2014-01-14 Knowles Electronics, Llc Bottom port surface mount silicon condenser microphone package
US9051171B1 (en) 2000-11-28 2015-06-09 Knowles Electronics, Llc Bottom port surface mount MEMS microphone
US7166910B2 (en) 2000-11-28 2007-01-23 Knowles Electronics Llc Miniature silicon condenser microphone
US8629552B1 (en) 2000-11-28 2014-01-14 Knowles Electronics, Llc Top port multi-part surface mount silicon condenser microphone package
US7242089B2 (en) 2000-11-28 2007-07-10 Knowles Electronics, Llc Miniature silicon condenser microphone
US9156684B1 (en) 2000-11-28 2015-10-13 Knowles Electronics, Llc Methods of manufacture of top port surface mount MEMS microphones
US7381589B2 (en) 2000-11-28 2008-06-03 Knowles Electronics, Llc Silicon condenser microphone and manufacturing method
US8629005B1 (en) 2000-11-28 2014-01-14 Knowles Electronics, Llc Methods of manufacture of bottom port surface mount silicon condenser microphone packages
US7439616B2 (en) 2000-11-28 2008-10-21 Knowles Electronics, Llc Miniature silicon condenser microphone
US9150409B1 (en) 2000-11-28 2015-10-06 Knowles Electronics, Llc Methods of manufacture of bottom port surface mount MEMS microphones
US7537964B2 (en) 2000-11-28 2009-05-26 Knowles Electronics, Llc Method of fabricating a miniature silicon condenser microphone
US9148731B1 (en) 2000-11-28 2015-09-29 Knowles Electronics, Llc Top port surface mount MEMS microphone
WO2002045463A2 (en) * 2000-11-28 2002-06-06 Knowles Electronics, Llc Miniature silicon condenser microphone and method for producing same
US8617934B1 (en) 2000-11-28 2013-12-31 Knowles Electronics, Llc Methods of manufacture of top port multi-part surface mount silicon condenser microphone packages
US8623710B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Methods of manufacture of bottom port multi-part surface mount silicon condenser microphone packages
US8624384B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Bottom port surface mount silicon condenser microphone package
US8624385B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Top port surface mount silicon condenser microphone package
US8652883B1 (en) 2000-11-28 2014-02-18 Knowles Electronics, Llc Methods of manufacture of bottom port surface mount silicon condenser microphone packages
US8623709B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Methods of manufacture of top port surface mount silicon condenser microphone packages
US8624386B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Bottom port multi-part surface mount silicon condenser microphone package
US8018049B2 (en) 2000-11-28 2011-09-13 Knowles Electronics Llc Silicon condenser microphone and manufacturing method
US7434305B2 (en) 2000-11-28 2008-10-14 Knowles Electronics, Llc. Method of manufacturing a microphone
US9139422B1 (en) 2000-11-28 2015-09-22 Knowles Electronics, Llc Bottom port surface mount MEMS microphone
WO2002045463A3 (en) * 2000-11-28 2003-05-15 Knowles Electronics Llc Miniature silicon condenser microphone and method for producing same
US8624387B1 (en) 2000-11-28 2014-01-07 Knowles Electronics, Llc Top port multi-part surface mount silicon condenser microphone package
US8704360B1 (en) 2000-11-28 2014-04-22 Knowles Electronics, Llc Top port surface mount silicon condenser microphone package
US8765530B1 (en) 2000-11-28 2014-07-01 Knowles Electronics, Llc Methods of manufacture of top port surface mount silicon condenser microphone packages
US9006880B1 (en) 2000-11-28 2015-04-14 Knowles Electronics, Llc Top port multi-part surface mount silicon condenser microphone
US9024432B1 (en) 2000-11-28 2015-05-05 Knowles Electronics, Llc Bottom port multi-part surface mount MEMS microphone
US9023689B1 (en) 2000-11-28 2015-05-05 Knowles Electronics, Llc Top port multi-part surface mount MEMS microphone
US9040360B1 (en) 2000-11-28 2015-05-26 Knowles Electronics, Llc Methods of manufacture of bottom port multi-part surface mount MEMS microphones
US9338560B1 (en) 2000-11-28 2016-05-10 Knowles Electronics, Llc Top port multi-part surface mount silicon condenser microphone
US9061893B1 (en) 2000-11-28 2015-06-23 Knowles Electronics, Llc Methods of manufacture of top port multi-part surface mount silicon condenser microphones
US9067780B1 (en) 2000-11-28 2015-06-30 Knowles Electronics, Llc Methods of manufacture of top port surface mount MEMS microphones
US8633064B1 (en) 2000-11-28 2014-01-21 Knowles Electronics, Llc Methods of manufacture of top port multipart surface mount silicon condenser microphone package
US9096423B1 (en) 2000-11-28 2015-08-04 Knowles Electronics, Llc Methods of manufacture of top port multi-part surface mount MEMS microphones
US9133020B1 (en) 2000-11-28 2015-09-15 Knowles Electronics, Llc Methods of manufacture of bottom port surface mount MEMS microphones
US9139421B1 (en) 2000-11-28 2015-09-22 Knowles Electronics, Llc Top port surface mount MEMS microphone
US6781231B2 (en) 2002-09-10 2004-08-24 Knowles Electronics Llc Microelectromechanical system package with environmental and interference shield
US7483542B2 (en) * 2004-08-31 2009-01-27 Kabushiki Kaisha Audio-Technica Condenser microphone
EP1883271A1 (en) * 2006-07-27 2008-01-30 Star Micronics Co., Ltd. Microphone case and condenser microphone
US7894622B2 (en) 2006-10-13 2011-02-22 Merry Electronics Co., Ltd. Microphone
US9374643B2 (en) 2011-11-04 2016-06-21 Knowles Electronics, Llc Embedded dielectric as a barrier in an acoustic device and method of manufacture
US9078063B2 (en) 2012-08-10 2015-07-07 Knowles Electronics, Llc Microphone assembly with barrier to prevent contaminant infiltration
US9794661B2 (en) 2015-08-07 2017-10-17 Knowles Electronics, Llc Ingress protection for reducing particle infiltration into acoustic chamber of a MEMS microphone package

Also Published As

Publication number Publication date
JPS5881000A (en) 1983-05-16
EP0077615B1 (en) 1986-04-30
CA1165859A (en) 1984-04-17
KR840002387A (en) 1984-06-25
DE3270879D1 (en) 1986-06-05
DK153619B (en) 1988-08-01
KR880000963B1 (en) 1988-06-04
DK153619C (en) 1988-12-19
DK450682A (en) 1983-04-20
IE53590B1 (en) 1988-12-21
IE822516L (en) 1983-04-19

Similar Documents

Publication Publication Date Title
US4424419A (en) Electret microphone shield
EP0077615B1 (en) Electret microphone shield
KR101155971B1 (en) Electro-acoustic transducer
US8428285B2 (en) Microphone screen with common mode interference reduction
JP4751057B2 (en) Condenser microphone and manufacturing method thereof
US6501019B2 (en) Isolation apparatus for electronic equipment
JP2825670B2 (en) High frequency circuit device shield structure
US5953414A (en) Piezo-electric speaker capsule for telephone handset
US6904155B2 (en) Electret capacitor microphone
US7697707B2 (en) Capacitor microphone unit
US4331840A (en) Electret transducer with tapered acoustic chamber
US4439642A (en) High energy ultrasonic transducer
CN112769988A (en) Electronic device
JP3805576B2 (en) Vibration transducer and acceleration sensor equipped with the vibration transducer
US9357313B2 (en) Microphone unit having a plurality of diaphragms and a signal processing unit
US5768369A (en) Telephone test set keypad with integrated dynamic microphone
JPH0629684A (en) Shield casing
US6975736B2 (en) Microphone
KR950001932B1 (en) Microphone cartridge
JP2009147470A (en) Condenser microphone and electronic apparatus
KR102002805B1 (en) Housing assembly comprising piezoelectric speaker unit to be installed on mobile terminal
JP2509454Y2 (en) Ultrasonic sensor
CN116592991A (en) Manufacturing method of vibration sensor, vibration sensor and electronic equipment
US10939192B2 (en) Electret condenser microphone and manufacturing method thereof
JPS59126400A (en) Transmitter and receiver for telephone set

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19821007

AK Designated contracting states

Designated state(s): CH DE FR GB IT LI NL SE

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB IT LI NL SE

ITF It: translation for a ep patent filed

Owner name: ING. C. GREGORJ S.P.A.

ET Fr: translation filed
REF Corresponds to:

Ref document number: 3270879

Country of ref document: DE

Date of ref document: 19860605

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19900831

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19900919

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19900921

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19900925

Year of fee payment: 9

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19900930

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19901031

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19910930

Ref country code: GB

Effective date: 19910930

Ref country code: CH

Effective date: 19910930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19911001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19920401

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19920529

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19920602

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 82305196.6

Effective date: 19920510