WO1982000745A1 - Contre-electrode pour microphone electrostatique et sa structure - Google Patents

Contre-electrode pour microphone electrostatique et sa structure Download PDF

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Publication number
WO1982000745A1
WO1982000745A1 PCT/JP1981/000047 JP8100047W WO8200745A1 WO 1982000745 A1 WO1982000745 A1 WO 1982000745A1 JP 8100047 W JP8100047 W JP 8100047W WO 8200745 A1 WO8200745 A1 WO 8200745A1
Authority
WO
WIPO (PCT)
Prior art keywords
microphone
plate
pack plate
pack
condenser
Prior art date
Application number
PCT/JP1981/000047
Other languages
English (en)
Japanese (ja)
Inventor
Co Ltd Primo
Original Assignee
Kishi K
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 Kishi K filed Critical Kishi K
Publication of WO1982000745A1 publication Critical patent/WO1982000745A1/fr

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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
    • H04R19/00—Electrostatic transducers

Definitions

  • the present invention relates to a condenser microphone and, more particularly, to a pack plate used for a fixed electrode of an electrostatic converter in such a microphone and a structure thereof.
  • a condenser microphone is an electroacoustic element that converts a sound wave into an electric waveform using an electrostatic converter composed of a fixed electrode and a movable electrode.
  • Fig. 1 shows a longitudinal cross-sectional view of a model that has been widely used in the past as such a microphone mouthpiece.
  • the vibrating membrane 1z extends on a ring frame to form a vibrating plate (movable electrode), and faces a pack plate (fixed electrode) 4 'having a flat surface with a narrow gap 3' therebetween. You. Thereby, a capacitance C is formed between the vibrating membrane 1 'and the pack plate.
  • a DC voltage is applied to the pack plate via a high resistance (not shown), and electric charges are charged between both electrodes.
  • a permanent charge is held between both electrodes by interposing an electret.
  • the thickness of the gap 5 ′ between the active membrane 1 ′ and the pack plate 4 is generally about 20 to 30 so that the capacitance C is formed, while the gap in the gap is thin.
  • Air layer force Shows the viscoelasticity of the fluid and controls the vibration of diaphragm 1.
  • the pack plate is provided with a plurality of through holes 5 ′ so that the gap 3 ′ communicates with the back room 0 ′.
  • the vibrating membrane 1 ′ vibrates, the air molecules in the gap 3 ′ flow in the radial direction as shown by the arrows, and escape from the through-hole 5 ′ to the back chamber 0 ′, and then again into the gap. Breathing is performed.
  • the air flowing through the narrow gap 3 ' has viscous resistance rA and elastic CA, this is the vibrating membrane as shown in the equivalent circuit diagram of the condenser microphone vibration system in Fig. 2.
  • An effective mass m Q of 1 'and an elastic Co by extension tension are added in series to control the velocity u of the vibrating membrane.
  • the 'viscous resistance rA is a force that has the effect of suppressing the resonance of the vibrating membrane 1' and flattening the characteristics.This is unfavorable because excessively lowering the sensitivity of the microphones .
  • elastic CA has the effect of increasing the resonance frequency of the diaphragm and extending the band, but if it is excessive, it produces a high-pitched beak and causes mechanical vibration of the diaphragm. This is also harmful, such as increased dance and reduced sensitivity. Therefore, when making a condenser microphone, it is necessary to determine the optimal conditions for elastic CA and viscous resistance rA. Basically important.
  • Such a conventional condenser microphone horn pack prep is composed entirely of a flat surface, and is provided with a groove, a through-hole, a closed hole, or the like, and is appropriately connected to the diaphragm. The air flow in the gap is adjusted.
  • the above-mentioned conventional adjustment means are no longer applicable.
  • pack electret microphone in which an electret film is applied to a pack plate, when the through hole 5 ′ is processed, the sagging or separation of the film or separation of the film occurs. Paris tends to occur, causing variations in sensitivity and characteristics.
  • the rotating surface is made a rotating curved surface and is made non-porous, and furthermore, a structure that does not require a ring for setting a gap is used.
  • the pack plate of the condenser microphone and its structure which facilitates the automation of the assembling work and enables the supply of a compact and high-performance condenser microphone at low cost, has been developed. With the purpose of providing Is what you do.
  • a pack plate of a capacitor microphone wherein the effective surface is formed of a non-porous and non-flat rotating surface, and a rotating surface of an effective non-porous and non-flat surface.
  • the inclined peripheral surface of the pack plate of the condenser microphone configured with the above is engaged with and held by the triangular cuts of a plurality of holding claws projecting from the insulating holding body, and the holding body is It is a component of a condenser plate of a condenser microphone that is fitted and fixed to another tube that forms part of the microphone.
  • Fig. 1 is a horizontal vertical sectional view of a conventional condenser microphone.
  • Fig. 2 is an equivalent circuit diagram of the condenser microphone of Fig. 1,
  • 3 (a) to 3 (e) are schematic longitudinal sectional views showing a basic form of a pack plate and a diaphragm according to an embodiment of the present invention
  • FIG. 4 is a perspective view showing the holding cylinder and the intermediate cylinder in the first embodiment
  • FIG. 5 is a longitudinal sectional view of the microphone mouth phone according to the first embodiment
  • FIG. 5 is a longitudinal sectional view of the microphone mouth phone according to the second embodiment
  • FIG. 7 is a holding cylinder and a diaphragm in the second embodiment.
  • a perspective view of the packing plate
  • FIG. 8 is a longitudinal sectional view of the microphone according to the third embodiment
  • FIG. 9 is a perspective view of the microphone according to the present invention having an electret film applied thereto.
  • FIG. 3 shows a basic form of the pack plate of the present invention and a configuration of a capacitor microphone horn which faces the diaphragm with a gap 3 therebetween.
  • a film of biaxially stretched polyester resin having a thickness of 5 or less is suitable, and a metal layer such as aluminum is deposited on the upper surface as a conductive surface. It is spread flat on the ring frame 2 and electrically conductively bonded. If the surface of the pack plate 4 that faces the vibrating membrane 1 and forms a capacitance is the effective surface 7, the surface 7 is constituted by a rotating curved surface that is not a flat surface.
  • the surface of a small disk-shaped pack plate 4 mainly made of metal is formed into a convex or concave lens shape.
  • the effective surface 7 is held by a highly insulating holding carrier, which will be described later, and faces the vibrating membrane 1 with a narrow gap 3 of about 20 to 30 to form a thin air layer.
  • a capacitance of about 20 to 30 PF is formed. .
  • the air flow in the gap is good.
  • the air bypasses the peripheral end face 9 of the pack plate 4 and can easily reach the back chamber ⁇ behind.As a viscoelastic effect of the thin air layer, the elastic CA is small and the viscous resistance r A is large. O PI be able to.
  • a top concave type in which the center of the convex surface is a concave surface, etc. Is effective.
  • the protruding type shown in Fig. 3 (e) is easy to process and can be manufactured at low cost.
  • the mushroom-shaped mushroom-shaped ones shown in Fig. 8 are suitable for ultra-small microphones, and can be widely used depending on the application.
  • the peripheral surface 9 of these pack plates is formed as an inclined surface in order to easily hold the pack plate, reduce stray capacitance, and improve air flow.
  • the insulating holder 10 made of synthetic resin has a right-angled triangular notch 1
  • the three holding claws 11 that form 1a are erected, and the pack plate 4 cuts the peripheral end face 9 while pushing the claws 11 slightly open using a jig (not shown). 1a is inserted, and the portion below the effective surface 7 is clamped by the claws 11. Then, this is press-fitted into a metal or resin intermediate cylinder 12.
  • the flat surface 13 at the upper end of the intermediate cylinder 12 is a reference surface on which the diaphragm is placed, and is attached to a jig for setting the size of the gap 3 (for example, a flat surface plate, not shown). And press-fit the holder 10 into the intermediate cylinder 12 until the gap between the jig and the effective surface 7 reaches a predetermined gap. When the position is determined, the holder 10 and the intermediate cylinder Inject an appropriate amount of cyanoacrylate instant adhesive from the lower end to the contact surface with 1 and 2 to fix them together.
  • This gap size setting is based on the capacitance measurement between the metal jig on which the flat surface 15 is placed and the pack plate 4 rather than the method of directly measuring the gap size as described above.
  • the indirect setting method is preferred.
  • the pack plate having completed the setting of the gap 3 is held by pressing the tapered surface below the effective surface by the pawls 11 and press-fitted into the intermediate cylinder 12 to be joined.
  • the peripheral end surface 9 of the pack plate 4 is held in an insulated manner by the inner surface of the intermediate cylinder 12 and the insulating retaining claws 11, so that the intermediate cylinder 1 2 There is no problem even if is made of metal.
  • a field-effect transistor 14 for constructing a capacitor microphone has a drain and source terminal 1 ⁇ soldered to a printed circuit board 17, and a coil spring 15 connected to the gate.
  • the gate When the gate is inserted and inserted through the transistor opening 25 provided in the holder 10, the gate conducts to the back of the pack plate 4 and signal output can be taken out between the drain and source. State.
  • the diaphragm is placed on the flat surface 13 at the upper end of the intermediate cylinder 12, the shield case 19 is fitted over it, and the lower end 20 of the case 19 is narrowed down.
  • the vibrating membrane 1 is grounded to the case 19 via the metal ring frame 2 to form a transistor circuit and complete an integrated structure as a microphone unit.
  • this microphone microphone In order to make this microphone microphone have directivity, as shown in Fig. 5, the holes 21 of the printed circuit board 17, the ventilation resistance 22 of the felt, etc., and the holes 18 of the holder 10
  • the sidetone can be introduced into the back room ⁇ ⁇ ⁇ ⁇ through the.
  • the microphones shown in Fig. I overall cross-sectional view
  • Fig. 7 partial configuration diagram
  • the holding body 10 has four holding claws 11. It has a right-angled triangular notch 11 1a and a flat surface 13 at the upper end.When the diaphragm is placed on the flat surface 13, a notch is made so that the specified gap size can be obtained with the packed plate that is sandwiched. It is configured by determining the position of 1 1a.
  • the holding body 10 holding the pack plate 4 is pressed into the case 19, and the screw at the lower end is inserted.
  • the lid 25 is tightened, the gap 7 is maintained between the surface 7 of the pack plate 4 and the diaphragm 1, and the claws 11 are tightened on the inner surface of the case 19.
  • the dimension between the lower surface of the notch 11a of the claw 11 of the holder 10 and the flat surface 13 at the upper end must be accurately obtained, and this is a limitation in processing.
  • the intermediate cylinder 12 in the first embodiment is not required, the outer diameter can be made thin. Therefore, this configuration is suitable for microphones that require miniaturization.
  • the screw cap at the lower end as shown
  • the pack plate 4 is mushroom-shaped, has fixing feet 4a at the center of the lower surface, and is inserted into the hole at the center of the holder 10 of the ecstatic green. Penetration, caulking and fixing
  • the flat surface 28 at the upper end of the shield case 19 is a reference surface for placing the diaphragm. In the case of assembly, this surface is placed on a metal flat plate (not shown) and While gradually measuring the capacitance between the plate 4 and the leveling plate, the holder 10 is gradually press-fitted. When the capacitance reaches a predetermined value, the connection between the holder 10, 10 and the case 19 is established. Inject an appropriate amount of cyanoacrylate instant adhesive from the rear end to the contact surface to complete the fixation.
  • the field-effect transistor 14 has the drain and source terminals 1 ⁇ attached to the printed circuit board 17, and the spring 15 is fitted to the gate to form the hollow caulking of the pack plate. Insert into the hole, connect cord 27 to terminal 1, and apply screw cap 25. Then, the diaphragm is placed on the flat surface 28 of the shield case 19, and the cap 29 having the front opening 30 is tightened to complete the microphone microphone.
  • the pack plate of the present invention used in the above three examples can be manufactured by using a precision die in a cold forging method using a metal plate such as a copper alloy or aluminum. High-precision products can be mass-produced and supplied at low cost.
  • the electret microphones are formed by vacuum molding. Can be simultaneously coated on the surface 7 of a large number of metal pack plates, and unnecessary parts (called ears) can be punched out with a taper. It is easy if you use the surface.
  • minute-polar processing (c:?
  • the gap setting step can be performed on the completed structure, there is no charge decay such as deterioration of tentacles, which is advantageous. is there.
  • This polarization treatment can be performed using either the high-pressure method, which is performed one by one, or the low-pressure method, which is performed simultaneously on a large number. That is, a ground electrode is inserted into the transistor opening 23 to ground the pack plate. In the high-pressure method, the needle end electrodes are opposed to each other, and a high-voltage collector of DC 25 KV or more is used. Discharge.
  • a multipole electrode for applying an electric field is adhered to the surface of a number of pack plate components arranged on a jig, and a voltage of 250 V DC or more is applied in a heating atmosphere. Slowly cools to obtain stable and good electret charges.
  • the pack plate 4 is non-porous, the effective surface 7 is composed of a rotating curved surface, and by selecting the radius of curvature, the best value of the viscoelastic effect is obtained, and the DC pass type or electret
  • a compact and high-quality condenser microphone can be constructed by applying it to any of the tube-type models.
  • the holding claw 10 Holds the holding claw 10 with the holding claw 11 and presses it into the intermediate cylinder to tighten it. Or, if it has supporting feet, it will be caulked to the center of the holding body 10 and fixed, so stable performance Can be maintained. And the effective surface 7 is a curved surface
  • the stray capacitance generated between the periphery of the pack plate and the ring frame 2 or the shield case 19 can be minimized to reduce sensitivity loss, improve ⁇ ratio, and increase nonlinearity. Distortion (mainly third harmonic distortion) can be improved, which is particularly advantageous when constructing a small microphone with a small diameter.
  • Capacitance, electric charge, insularity, etc. can be checked in a timely manner in the intermediate process of assembling by using the transistor opening, the early detection and rejection of defective products can be achieved, and the quality can be improved. Thorough management can be implemented.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)

Abstract

Contre-electrode, et sa structure, utilisee pour une electrode stationnaire d'un convertisseur electrostatique pour un microphone electrostatique. La surface effective (7) de la contre-electrode (4) est depourvue de trous et n'est pas plate mais definit un hyperboloide de revolution, laquelle surface est soit convexe soit concave, soit une composition de ces formes. De plus, la surface du bord peripherique (9) de la contre-electrode (4) est inclinee dans un etat evase, et est engagee dans les ouvertures decoupees triangulaires (11a) d'une pluralite de crochets de retenue (11) se projetant a partir d'un dispositif de retenue isolant (10), de maniere a retenir la contre-electrode, et le dispositif de retenue (10) s'engage de maniere fixe avec un cylindre intermediaire (12) faisant partie d'un microphone. L'air entre les electrodes se deplace autour de la surface du bord peripherique (9) de la contre-electrode (4) pour ainsi atteindre une arriere chambre (6) derriere la contre-electrode (4).
PCT/JP1981/000047 1980-08-21 1981-03-06 Contre-electrode pour microphone electrostatique et sa structure WO1982000745A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP80/113962800821 1980-08-21
JP11396280A JPS5739700A (en) 1980-08-21 1980-08-21 Back plate of condensor microphone and its constituent

Publications (1)

Publication Number Publication Date
WO1982000745A1 true WO1982000745A1 (fr) 1982-03-04

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ID=14625558

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1981/000047 WO1982000745A1 (fr) 1980-08-21 1981-03-06 Contre-electrode pour microphone electrostatique et sa structure

Country Status (2)

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JP (1) JPS5739700A (fr)
WO (1) WO1982000745A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1120996A2 (fr) 2000-01-27 2001-08-01 AKG Acoustics GmbH Transducteur électro-acoustique
EP1296536A2 (fr) * 2001-09-20 2003-03-26 AKG Acoustics GmbH Transducteur électroacoustique

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60134573A (ja) * 1983-12-22 1985-07-17 Fuji Photo Film Co Ltd 映像合成記録装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50110322A (fr) * 1974-02-06 1975-08-30
JPS5114046A (ja) * 1974-07-25 1976-02-04 Hitachi Shipbuilding Eng Co Maikuroppon
JPS51131315A (en) * 1975-05-10 1976-11-15 Hitachi Zosen Corp Microphone
JPS5586291A (en) * 1978-12-23 1980-06-28 Toshiba Corp Condenser type microphone

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50110322A (fr) * 1974-02-06 1975-08-30
JPS5114046A (ja) * 1974-07-25 1976-02-04 Hitachi Shipbuilding Eng Co Maikuroppon
JPS51131315A (en) * 1975-05-10 1976-11-15 Hitachi Zosen Corp Microphone
JPS5586291A (en) * 1978-12-23 1980-06-28 Toshiba Corp Condenser type microphone

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1120996A2 (fr) 2000-01-27 2001-08-01 AKG Acoustics GmbH Transducteur électro-acoustique
US6510231B2 (en) 2000-01-27 2003-01-21 Akg Acoustics Gmbh Electroacoustic transducer
AT411513B (de) * 2000-01-27 2004-01-26 Akg Acoustics Gmbh Elektroakustischer wandler
EP1296536A2 (fr) * 2001-09-20 2003-03-26 AKG Acoustics GmbH Transducteur électroacoustique
EP1296536A3 (fr) * 2001-09-20 2004-01-28 AKG Acoustics GmbH Transducteur électroacoustique

Also Published As

Publication number Publication date
JPS5739700A (en) 1982-03-04

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