CN2258680Y

CN2258680Y - Ultrathin type eletret microphone

Info

Publication number: CN2258680Y
Application number: CN 96209183
Authority: CN
Inventors: 李义顺; 李文堂
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-30
Filing date: 1996-04-30
Publication date: 1997-07-30
Anticipated expiration: 2006-04-30

Abstract

The utility model relates to an electret microphone, and the utility model is composed of a casing, a sheet-typed packaged transistor, a metal gate barrel, a nylon gasket, and a dust-proof cushion pasted on one end face of the casing. The sheet-shaped packaged transistor comprises a transistor core and a double-sided printed circuit board, and an S-shaped grat ring which is not closed is arranged in the circuit board. The metal gate barrel is composed by the pasting of the gate barrel and an electret film, and an edge face of the other end of the gate barrel is appressed with the gate ring on an inner face of the circuit board. The space part of the metal barrel and the nylon gasket forms a resonant cavity at the inner part of the casing, and the vibration signals of sound are made to be changed into electric signals to be injected in a gate electrode. The utility model has the advantages of simple structure, convenient assembly, super thin property, etc.

Description

Ultrathin Electret condenser microphone

The utility model relates to a kind of acoustical-electrical transducer spare, relates to a kind of Electret condenser microphone or rather.

Existing Electret condenser microphone is made of shell, microphone core, nylon washer, foil electret and dust-proof cushion assembling.Wherein the microphone core is made of circuit board, rubber blanket, plastic stent, transistor, the assembling of metal pole piece again.Fig. 1 illustrates the structure and the assembly relation thereof of microphone core, and Fig. 2 illustrates the structure and the assembly relation thereof of Electret condenser microphone.During assembling microphone core, need utilize source, drain electrode leading foot S, the through hole 131,121,111 of D on plastic stent 13, rubber blanket 12 and circuit board 11 of transistor 14 that three 11,12,13 is located in together earlier, and S, D the two poles of the earth are welded on the circuit board 11, then metal pole piece 15 is pressed in the plastic stent 13, relies on pressure to contact and constitute microphone core 10 with the grid G of transistor 14.During the assembling Electret condenser microphone, need earlier foil electret 21 and nylon washer 22 to be packed in the shell 23, the microphone core 10 of packing into is then pasted dust-proof cushion 24 at last.

As seen from Figure 1, Figure 2, Electret condenser microphone is made of at least nine basic building block assemblings, have the problem that part is many, assembly process is many, thereby production efficiency is lower; Owing to adopt the transistor 14 after encapsulation, thus whole Electret condenser microphone volume more greatly, thicker, be unfavorable for microminiaturization and use thereof; Transistor 14 grid G form point with metal pole piece 15 depended on pressure and contact, and open circuit rate high reliability is poor; Dust-proof cushion stick on be difficult on shell one transverse plane neat, firm.

The purpose of this utility model is that the Electret condenser microphone to said structure makes improvements design, make simple in structure, help assembling and form ultrathin microphone, to enhance productivity, to improve reliability of products and acoustic-electric conversion performance.

Ultrathin Electret condenser microphone of the present utility model is made of shell, microphone core, dust-proof cushion and nylon washer assembling, it is characterized in that;

Described microphone core is made of chip packaged transistor and metal gate barrel assembling; Described chip packaged transistor comprises double-sided printed-circuit board and the transistor dies that is bonded on the double-sided printed-circuit board inner face, described metal gate barrel comprises foil electret and the metal gate tube that is bonded on the foil electret, and metal gate barrel opening ora terminalis face is connected with the grid of transistor dies; Described shell top end surface center position is provided with through hole.

Be manufactured with source electrode conducting ring district and drain electrode conduction region on the described double-sided printed-circuit board outer surface, be manufactured with S shape gate loop conduction region on the described double-sided printed-circuit board inner face, the drain electrode conduction region that is connected by source hole with source electrode conducting ring district on the outer surface with outer surface on the drain electrode conduction region that is connected by drain holes of drain electrode conduction region, the grid of described transistor dies, source electrode, the drain electrode respectively with the circuit board inner face on S shape gate loop conduction region, the source electrode conduction region, the drain electrode conduction region connects, and the opening ora terminalis face of described metal gate barrel is adjacent to described circuit board S shape gate loop conduction region.

Described shell top peripheral region has annular protrusion, and described dust-proof cushion sticks in the groove that the shell top convexes to form by the periphery annular.

Space segment between metal gate barrel and nylon washer portion in the enclosure forms a resonant cavity and foil electret closely is interposed in this cavity, through-hole alignment on the center of foil electret and the shell, dust-proof cushion then covers through hole from housing exterior, after entering resonant cavity by dust-proof cushion by through hole, voice signal promptly in the chamber, produces resonance, promote foil electret with peak swing, make foil electret with the variation of sound in cavity double vibrations, the signal of telecommunication that mechanical oscillation are transformed into variation injects the grid of chip packaged transistor by grid bucket, S shape gate loop conduction region.Because transistorized self-characteristic, the change in voltage that its grid is small all can make the electric current that a respective change is arranged in the drain electrode, is coupled to subordinate's semiconductor device amplification etc. by external coupling capacitance, and the promotion loudspeaker are reduced into sound.

Further specify technology of the present utility model below in conjunction with the embodiment accompanying drawing:

Fig. 1, microphone core existing structure and assembly relation schematic diagram thereof;

Fig. 2, Electret condenser microphone existing structure and assembly relation schematic diagram thereof;

The chip packaged transistor planar structure schematic diagram of Fig. 3, ultrathin Electret condenser microphone;

The structure of Fig. 4, ultrathin Electret condenser microphone and assembly relation schematic diagram thereof;

The sectional structure schematic diagram of Fig. 5, ultrathin Electret condenser microphone;

The electrical schematic diagram of Fig. 6, Electret condenser microphone.

Addressed before Fig. 1, Fig. 2 illustrate and repeated no more.

Referring to Fig. 3, the chip packaged transistor is made up of double-sided printed-circuit board 31 and transistor dies 32, double-sided printed-circuit board outside 311 is manufactured with source electrode conducting ring district S and drain electrode conduction region D respectively, is manufactured with S shape gate loop conduction region G, source electrode conduction region S and drain electrode conduction region D on the double-sided printed-circuit board inner face 312 respectively and forms the transistor supporting structure.Tube core 32 (bonding by reducible conducting resinl) is on S shape gate loop conduction region G, and tube core grid (substrate) electrically contacts with S shape gate loop conduction region.The source on printed circuit board (PCB) two sides, leakage conductance electricity district is respectively by plated-through

hole

33,34 short circuits, the source of tube core, drain electrode respectively with circuit board inner face 312 on the source, leak the conduction region welding, and fill out tube sealing core and welding wire with black glue.Plated-through

hole

33,34 also can be used for connecting external circuit on the circuit board outside 311.

Referring to Fig. 4,41 is the chip packaged transistor.42 is the grid bucket, metal garden tube 421 and foil electret 422 bonding formations, and foil electret is made by macromolecular material, and the one side of touching with the grid socket joint is coated with conductive layer.The outer garden of metal garden tube (as copper) is non-conductive, have with chip packaged transistor 41 inner faces on the identical diameter of S shape gate loop conduction region G.Finishing grid bucket 42 after the stickup needs do foil electret the operation processing of iunjected charge (charging), makes it become one and has the tubbiness grid of electret and be referred to as the grid bucket.

44 one-tenth garden tubbiness of shell, bucket bottom center offers through hole 441 (see figure 5)s in the position, and bucket end outer peripheral edges have projection and form annular walls 442.

Pack into nylon washer 43, grid bucket 42, chip packaged transistor 41 in the shell 44 in order and seal, in the groove that the shell end face is formed by annular walls 442, paste dust-proof cushion 45 and promptly finish whole assembly workings.

Referring to Fig. 5, Electret condenser microphone after the assembling is dust-proof cushion 45, shell 44, nylon washer 43, grid bucket 42 (comprising foil electret 422 and grid tube 421) and chip packaged transistor (comprising transistor dies 32 and double-sided printed-circuit board 31) as shown in FIG. from left to right in proper order.On shell 44 end faces central through hole 441 is arranged; grid bucket 42 ora terminalis faces are close to not sealing on the double-sided printed-circuit board 31 (S shape) grating ring; the source of tube core 32, drain electrode are by corresponding S on lead 47 and the circuit board; the D conduction region connects and is connected with

hole

33,34, protection is arranged with deceiving glue 46 on tube core 32 and the lead 47.

In conjunction with referring to Fig. 5, grid bucket 42 is formed a resonant cavity and is clipped in foil electret 422 in the cavity tightly in microphone inside with the space segment of nylon washer 43, through hole 441 on the centrally aligned shell 44 of foil electret 422, the dust-proof cushion made from fiber 45 covers through hole 441 just, in order to avoid dust, moisture etc. enter in the cavity, the annular walls 442 of shell one end peripheral region blocks dust-proof cushion 45 just, be difficult for being shifted or coming off, thereby the conductive layer of 422 1 plating of foil electret is parallel with shell 44 bottom surfaces and the approaching capacitor C i that forms of distance.

After voice signal enters resonant cavity by dust-proof cushion 45 by outer casing through hole 441, promptly in the chamber, produce resonance, promote foil electret 422 with peak swing, make it with sound variation double vibrations in cavity.Foil electret is transformed into the signal of telecommunication with this mechanical oscillation and the signal of telecommunication that changes is injected the grid G of chip packaged transistor by the S shape grating ring conduction region on Ci, grid tube 421 and the circuit board, the change in voltage that its grid is small all can make the electric current that respective change is arranged on the drain D, this variable-current is coupled to subordinate's amplifier by external capacitor CO again, can promote loudspeaker the signal of telecommunication is reduced into sound.

The utility model adopts field-effect transistor, be because field-effect transistor have noise low, pass auxilliary coefficient height, input impedance height, the low characteristics of output impedance, can be preferably and prime input circuit and back level amplifying circuit coupling.

Electret condenser microphone of the present utility model can transform the assembling of transistorized encapsulated moulding and microphone as one and finish, and do not assemble the microphone core separately, for the super type of changing into of approaching of microphone provides the most basic condition, ultrathin Electret condenser microphone can be widely used in mobile communication, miniature hearing aid, the miniature monitoring, and with low cost; Whole microphone has five parts, assembles simply, makes things convenient for, helps enhancing productivity and assembly quality.

Claims

1, a kind of ultrathin Electret condenser microphone is made of shell, microphone core, dust-proof cushion and nylon washer assembling, it is characterized in that:

2, ultrathin Electret condenser microphone according to claim 1, it is characterized in that: be manufactured with source electrode conducting ring district and drain electrode conduction region on the described double-sided printed-circuit board outer surface, be manufactured with S shape gate loop conduction region on the described double-sided printed-circuit board inner face, the drain electrode conduction region that is connected by source hole with source electrode conducting ring district on the outer surface with outer surface on the drain electrode conduction region that is connected by drain holes of drain electrode conduction region, the grid of described transistor dies, source electrode, the drain electrode respectively with the circuit board inner face on S shape gate loop conduction region, the source electrode conduction region, the drain electrode conduction region connects, and the opening ora terminalis face of described metal gate barrel is adjacent to described circuit board S shape gate loop conduction region.

3, ultrathin Electret condenser microphone according to claim 1 is characterized in that: described shell top peripheral region has annular protrusion, and described dust-proof cushion sticks in the groove that the shell top convexes to form by the periphery annular.