Summary of the invention
The purpose of this utility model is in order to overcome the deficiencies in the prior art, a kind of digital microphone that can be used for Reflow Soldering and SMT technology to be provided.
To achieve the above object of the invention, the technical solution adopted in the utility model is: a kind of digital microphone, comprise miaow head assembly and outer circuit board component, outer circuit board component comprises outer wiring board, and is mounted on chip, peripheral components on the outer wiring board and the output that is connected with peripheral hardware; Described miaow head assembly and outer wiring board are electrically connected, and outer circuit board component and miaow head assembly are fixed into an overall digital microphone.
Further, described miaow head assembly comprises that shell and order place zona, diaphragm, pad, backplane, copper ring, cavity and the outmost interior wiring board of shell, wherein cavity is concentric is enclosed within the copper ring periphery, the one side of wiring board has connection pads in described, and described connection pads and outer wiring board are electrically connected; There is crimping at described shell aperture place, and described crimping is limited in the cavity of shell formation by the other parts of interior wiring board with miaow head assembly.
Further, conductive silver glue or tin cream are arranged between the connection pads of described outer wiring board and interior wiring board, wiring board is electrically connected with outer wiring board in making.
Further, the middle part of described interior wiring board also has the hole that is used to dodge outer circuit chip on board and peripheral components.
Further, described chip, connection pads and peripheral components are positioned at the first surface of outer circuit plate, and the lead-out terminal that is connected with peripheral hardware is positioned at its second surface.
Further, the second surface of described outer circuit plate is provided with five lead-out terminals that are connected with peripheral hardware; Perhaps the second surface of outer circuit plate is provided with four lead-out terminals that are connected with peripheral hardware, and the GND of microphone end communicates with shell, and shell is held as GND.
Further, describedly become an integral body with outer circuit board component and miaow head assembly are bonding, be the crimping place of shell aperture by refractory seals glue or conductive silver glue and outside wiring board bonding.
Further again, also be provided with sound hole on described outer casing bottom and/or the outer wiring board.
Adopt the digital microphone of technical solutions of the utility model, because chip and peripheral components are arranged on the outer wiring board, thereby can adopt the technology of traditional microphones maturation to accomplish a plurality of outputs that digital microphone is required, and make compact conformation.
The components and parts on the outer wiring board are dodged in perforate on interior wiring board, make that the volume of digital microphone is smaller and more exquisite.
Adopt conductive silver glue or tin cream to connect inside and outside wiring board by Reflow Soldering, rather than with bonding wire or the weldering flexible circuit board technology, make when digital microphone is simple in structure, compact to have high-temperature stability, conveniently carry out Reflow Soldering, and performance is more stable, electromagnetic interference diminishes.
Since shell and outside all have sound hole on the wiring board, help adjusting the directive property of digital microphone.
Embodiment
As shown in Figure 1, a kind of digital microphone that the utility model embodiment provides in the cavity that cylindrical housing 1 forms, is disposed with zona 14, diaphragm 2, pad 13 and backplane 3, be cavity 4 and the copper ring 12 that is provided with one heart then, outermost is interior wiring board 5.Wherein shell 1 bottom has at least one sound hole 16, and bottom inside offers balancing slit 15, and opening part is fixed all parts in shell 1 inner chamber by the crimping technology.Wherein the external diameter of zona 14, diaphragm 2, pad 13, backplane 3 and cavity 4 all is slightly less than the internal diameter of shell 1.
Interior wiring board 5 is common double-sided wiring board, and its effect is the outer wiring board 7 of stressed and conducting front end acoustic vibration structure and rear end when crimping, therefore in wiring board 5 and shell 1 be tight fit, have the gap therebetween hardly.It outside the interior wiring board 5 outer circuit board component.Interior wiring board 5 is provided with connection pads 6, and outer wiring board 7 also is provided with connection pads 6 accordingly, and uses tin cream or conductive silver glue 11 that they are connected, to finish the transmission that input signal arrives outer wiring board 7 through copper ring 12 again to interior wiring board 5.Outer wiring board 7 is a doubling plate, the one side that it is inside is referred to herein as first surface, is pasted with chip 8 and peripheral components 17 on it, other electronic devices and components beyond peripheral components 17 representative office's chips comprise resistance, electric capacity, CMOS, FET tube core, A/D converter etc. herein.
What present embodiment chips 8 adopted is nude film, needs on it to connect outer wiring board 7 by nation's alignment 10.Therefore need between chip 8 and outer wiring board, to burn-on again nation's alignment 10, at last with chip package glue 9 be coated in chip 8 outsides with protect chip 8 and and outer wiring board 7 between nation's alignment 10.The one side that outer wiring board 7 is outside is referred to herein as second surface, which is provided with five outputs 18, and output 18 also is a kind of pad of form, is used for being connected with the peripheral circuit of client.In addition the crimping place of shell 1 opening and outside between the wiring board 7, also used refractory seals glue (as resistant to elevated temperatures Epoxy glue), to keep the sealing of microphone integral body.What select for use in the present embodiment is that conductive silver glue 11 replaces refractory seals glue herein.
The manufacture method of a kind of digital microphone that the utility model embodiment provides comprises the assembling of miaow head assembly, outer circuit board component mount and assemble three steps.
The installation step of the miaow head assembly of present embodiment is as follows: in the circular cavity that shell 1 forms, order has been placed zona 14, diaphragm 2, pad 13 and backplane 3, their external diameter all is slightly less than the internal diameter of shell 1, with shell 1 be matched in clearance, therefore can very easily they be placed in proper order in the cavity that shell 1 forms.Place circular cavity 4 then, again copper ring 12 is placed in the space of cavity 4 centres; Between cavity 4 and shell 1 and the copper ring 12, certain interval is arranged all also.Behind the wiring board 5, as a whole with traditional flanging process integration, this part insider generally abbreviates the miaow head as in placing at last.All parts of this miaow head assembly are exotic material and make, and therefore can cross unleaded Reflow Soldering.This miaow head assembly is integrated by traditional crimping technology and is formed, and technical maturity is simple, and consistency is better.Briefly, miaow head assembled mainly is according to the manufacture method that has the column type microphone now miaow head assembly to be combined, and parts wherein are except that wiring board changes the interior wiring board 5 of present embodiment into, and other is all identical with former microphone.
It is as follows that the outer wiring board of present embodiment mounts step: adopt SMT technology, chip 8 and peripheral components 17 (comprising resistance, electric capacity, CMOS, FET tube core, A/D converter etc.) dress are attached on the outer wiring board 7, outer circuit board component has just been carried out.But the chip 8 that the utility model embodiment adopts is nude films, and chip 8 is bonded on the outer wiring board 7, is electrically connected by nation's alignment 10 and outer wiring board 7 then.Therefore need between chip 8 and outer wiring board, to burn-on again nation's alignment 10, at last with chip package glue 9 be coated in chip 8 outsides with protect chip 8 and and outer wiring board 7 between nation's alignment 10.
Key point of the present utility model is mounted on chip 8 and peripheral components 17 on the outer wiring board 7 exactly.Outer wiring board effect is that carrying IC chip is connected with other capacitance resistance elements and with external client; Adopt this kind arrangement can be so that the digital microphone compact conformation, and can satisfy the requirement of a plurality of outputs of digital microphone.
The last number of assembling steps of present embodiment, the step that is about to miaow head assembly and the combination of outer circuit board component is as follows: with the opening crimping place of the interior wiring board and the shell of miaow head assembly, with outer circuit board component with the bonding integral body that becomes a sealing of resistant to elevated temperatures conductive silver glue (such as the high temperature resistant Epoxy glue that is mixed with silver powder).Make copper ring 12 by interior wiring board 5 with and on connection pads 6, connect outer wiring board by conductive silver glue 11 again, be connected to the input utmost point of chip 8, form signal input.Conductive silver glue 11 herein also can substitute with tin cream.Re-use refractory seals glue (also can use resistant to elevated temperatures Epoxy glue herein) and make outer wiring board 7 and miaow head components keep sealing, so far form digital microphone of the present utility model.
Interior wiring board 5 middle parts of the utility model embodiment, be provided with the circular hole of certain specification, the hole of given shape also can be set, according to the requirement that chip 8 and peripheral components 17 mount the position to dodge chip 8 and peripheral components 17, better conserve space makes structure compact more.
5 outputs 18 that are connected with the user side peripheral hardware are arranged: be respectively GND, CLK, VDD, OUTPUT, L/R on the outer wiring board 7 of the utility model embodiment.Wherein, the GND port also can be arranged on the shell 1, makes the output on outer wiring board 7 surfaces be reduced to 4.
The sound hole 16 of the utility model embodiment is arranged on shell 1 bottom, also can be arranged on the outer wiring board 7, perhaps be provided with simultaneously with shell 1 bottom and outer wiring board 7 on so that be easy to regulate the directive property of microphone.
The utility model embodiment also is provided with balancing slit 15 in the bottom of shell 1.
Digital microphone is because output many (4~5), as adopt traditional circular packaging technology, and the one, the extremely complicated and manufacturing difficulty with the connector design of client, the 2nd, circular configuration moves in braid easily, the calibrating position difficulty is unfavorable for the SMT automated production of client.And other polygonal design, the one, encapsulation difficulty is big, (if adopt adhesion process, just can't use traditional compression joint type structure, thereby sealing is poor; And the employing flanging process, then the crimping difficulty is big.) the 2nd, needing to change nearly all part, the early investment cost is huge.The digital microphone of technical solutions of the utility model, its miaow head assembly remains traditional compression joint type, and self performance belongs to matured product through producing for many years and practical application; The square outer wiring board 7 of outer subsides is to satisfy the demand of chip mounter calibrating position.And chip 8 and other peripheral components 17 are mounted on the one side of outer wiring board 7, have overcome in the existing product the not enough problem of tie point between the wiring board 5 and outer wiring board 7, make compact conformation, stable performance simultaneously.Adopt conductive silver glue mode bonding or Reflow Soldering to be combined into an integral body in addition between miaow head assembly and the outer circuit board component, compare the technology of traditional bonding wire craft or weldering flexible circuit board, when making compact conformation, can also obtain resistance to elevated temperatures, help the automation assembling of client, make that simultaneously electromagnetic interference diminishes.
Above content be in conjunction with concrete preferred implementation to further describing that the utility model is done, can not assert that concrete enforcement of the present utility model is confined to these explanations.For the utility model person of an ordinary skill in the technical field, under the prerequisite that does not break away from the utility model design, can also make some simple deduction or replace, all should be considered as belonging to protection range of the present utility model.