A kind of directive property MEMS microphone
Technical field
The utility model relates to acoustic-electric switch technology, is specifically related to a kind of directive property MEMS microphone.
Background technology
MEMS microphone is a kind of acoustical-electrical transducer made based on MEMS technology, the features such as volume is little, good frequency response, noise are low that it has.Along with compact, the slimming development of electronic equipment, MEMS microphone is applied on the electronic equipments such as such as mobile phone, panel computer, camera, hearing aids, intelligent toy and monitoring device more and more widely.
MEMS microphone generally includes MEMS chip and ASIC (Application Specific Integrated Circuit, functional integrated circuit) chip, be electrically connected by wire between the two, sound enters microphone from single acoustic aperture and acts on the vibrating diaphragm of MEMS chip, the MEMS microphone of this class formation can only do omni-directional microphone, cannot realize the directive property of sound.
Utility model content
The purpose of this utility model is to provide a kind of MEMS microphone with good directive property, and detailed technology scheme is as follows:
A kind of directive property MEMS microphone, comprising: substrate; All arrange on the substrate and the MEMS chip be electrically connected to each other and asic chip; Shell, described shell is connected with described substrate and surrounds encapsulation cavity, and described MEMS chip and described asic chip are arranged on described encapsulation inside cavity; First acoustic aperture, is arranged on described substrate, is positioned at below described MEMS chip; Second acoustic aperture, on the described substrate being arranged on described encapsulation cavity or on described shell; And damping fin, described damping fin covers described second acoustic aperture from described encapsulation inside cavity.
Preferred technical scheme further, described damping fin is provided with intensive through hole.
Preferred technical scheme further, described damping fin offers passage, and described second acoustic aperture is aimed in one end of described passage, and the other end is towards described encapsulation inside cavity.
Preferred technical scheme further, described passage is rectilinear form or bending shape.
Preferred technical scheme further, described passage is shape.
Preferred technical scheme further, one end of the second acoustic aperture described in described channel alignment is arranged to network structure and/or described passage is arranged to network structure towards one end of described encapsulation inside cavity.
Further preferred technical scheme, one end of the second acoustic aperture described in described channel alignment is coated with Air Filter and/or described passage and is coated with Air Filter towards one end of described encapsulation inside cavity.
Preferred technical scheme further, described substrate is the bottom of described encapsulation cavity, and described second acoustic aperture is arranged on the top of described encapsulation cavity.
Preferred technical scheme further, described shell comprises upper cover and sidewall, and described second acoustic aperture is arranged on described upper cover or described sidewall.
Preferred technical scheme further, the material of described damping fin is following arbitrary: silicon, pottery, wiring board, sheet metal, moulding.
MEMS microphone of the present utility model is provided with two acoustic aperture, be provided with at the second acoustic aperture place damping fin with reduce the acoustic pressure at the second acoustic aperture place and sound phase shift from the target sound source of the first acoustic aperture, it is identical with the amplitude of target sound source after the sound of target sound source is entered from the second acoustic aperture, thus increase target sound source to the effect acoustic pressure of vibrating diaphragm, MEMS chip produces the signal of telecommunication and exports under the acting in conjunction of two-way sound wave, achieves good directive property.
Accompanying drawing explanation
Fig. 1 is the structural representation of the utility model directive property MEMS microphone first embodiment.
Fig. 2 is the A-A schematic cross-section of Fig. 1 first embodiment damping fin.
Fig. 3 is the structural representation of the utility model directive property MEMS microphone second embodiment.
Fig. 4 is the enlarged diagram of the B position of Fig. 3 second embodiment damping fin.
Fig. 5 is the C-C schematic cross-section of Fig. 4.
Fig. 6 is the structural representation that damping fin access port adds Air Filter
Fig. 7 is the structural representation of the utility model directive property MEMS microphone the 3rd embodiment.
Fig. 8 is the structural representation of the utility model directive property MEMS microphone the 4th embodiment.
Fig. 9 is the structural representation of the utility model directive property MEMS microphone the 5th embodiment.
Figure 10 is the structural representation of the utility model directive property MEMS microphone the 6th embodiment.
Reference numeral
1 substrate, 2 shells, 3MEMS chip, 4ASIC chip, 5 wires, 6 damping fins;
21 upper covers, 22 sidewalls, 60 via matrixes, 61 passages, 62 network structures, 63 Air Filters;
The operatic tunes after the operatic tunes, 400 before 100 first acoustic aperture, 200 second acoustic aperture, 300.
Embodiment
Be described below in detail embodiment of the present utility model, the example of embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the utility model, and can not being interpreted as restriction of the present utility model.
With reference to the first embodiment that Figure 1 shows that MEMS microphone, comprising:
Substrate 1, the shell 2 be made up of upper cover 21 and sidewall 22, substrate 1 are fixedly connected with shell 2 and surround encapsulation cavity.
Encapsulation inside cavity is provided with MEMS chip 3 and asic chip 4, and MEMS chip 3 and asic chip 4 all mount on substrate 1, and both are electrically connected by wire 5.
Encapsulation cavity offers the first acoustic aperture 100 and the second acoustic aperture 200.
Wherein, the first acoustic aperture 100 is offered on substrate 1 and just to MEMS chip 3, MEMS chip 3 and substrate 1 surround the front operatic tunes 300.Sound enters the front operatic tunes 300 from the first acoustic aperture 100, acts on the vibrating diaphragm of MEMS chip 3 from downside.
Wherein, substrate 1 is the bottom of encapsulation cavity, and the second acoustic aperture 200 is offered on substrate 1 equally, and the first acoustic aperture 100 and the second acoustic aperture 200 are positioned at the same side of microphone.Damping fin 6 covers the second acoustic aperture 200 from encapsulation inside cavity, and sound, from the second acoustic aperture 200 operatic tunes 400 after damping fin 6 reduces to enter after acoustic pressure, acts on the vibrating diaphragm of MEMS chip 3 from upside.Shown in figure 2, damping fin 6 is for offering the silicon chip of intensive through hole, and intensive through hole defines via matrix 60.
Sound on the one hand enters the front operatic tunes 300 from the first acoustic aperture 100, acts on the vibrating diaphragm of MEMS chip 3 from downside, on the other hand from the second acoustic aperture 200 operatic tunes 400 after damping fin 6 reduces to enter after acoustic pressure, acts on the vibrating diaphragm of MEMS chip 3 from upside.MEMS microphone of the present utility model is provided with two acoustic aperture, be provided with at the second acoustic aperture place damping fin with reduce the acoustic pressure at the second acoustic aperture place and sound phase shift from the target sound source of the first acoustic aperture, it is identical with the amplitude of target sound source after the sound of target sound source is entered from the second acoustic aperture, thus increase target sound source to the effect acoustic pressure of vibrating diaphragm, MEMS chip produces the signal of telecommunication and exports under the acting in conjunction of two-way sound wave, achieves good directive property.
Wherein, the material of damping fin 6 can be following arbitrary: silicon, pottery, wiring board, sheet metal, moulding (exotic material).
With reference to Figure 3 shows that the second embodiment of the present utility model, principle is identical with the first embodiment, structure and first embodiment of damping fin 6 are distinguished to some extent: damping fin 6 is for offering the silicon chip of passage 61, the second acoustic aperture 200 is aimed in one end of passage 61, the other end is towards encapsulation inside cavity, and the aperture of passage 61 is less than the aperture of the second acoustic aperture 200.Sound enters the rear operatic tunes 400 from the second acoustic aperture 200 via passage 61.
One end that passage 61 aims at the second acoustic aperture 200 is provided with network structure, and one end that certain passage 61 aims at the second acoustic aperture 200 also can be completely through, and passage 61 also can be provided with network structure or completely through towards one end of encapsulation inside cavity.Network structure is mainly used in preventing dust from entering microphone internal influence microphone products performance from acoustic aperture.In one embodiment, shown in figure 3, Fig. 4, Fig. 5, multiple tiny through hole can be offered at the port B place of the passage 61 of damping fin 6 and form network structure 62.In another embodiment, shown in figure 6, Air Filter 63 can be covered on the port of passage 61 as network structure by modes such as stickups.
Passage 61 shown in Fig. 3 is shape, but the utility model is not limited thereto, and passage can also be rectilinear form, curve shape or other bending shape.
With reference to Figure 7 shows that the 3rd embodiment of the present utility model, principle is identical with the first embodiment, position and first embodiment of the second acoustic aperture 200 are distinguished to some extent: the second acoustic aperture 200 is arranged on the top of encapsulation cavity, namely be arranged on upper cover 21, the first acoustic aperture 100 is positioned at the relative both sides of microphone with the second acoustic aperture 200.
With reference to Figure 8 shows that the 4th embodiment of the present utility model, principle is identical with the first embodiment, and position and first embodiment of the second acoustic aperture 200 are distinguished to some extent: the second acoustic aperture 200 is arranged on the sidewall of encapsulation cavity, is namely arranged on sidewall 22.
With reference to Figure 9 shows that the 5th embodiment of the present utility model, principle is identical with the second embodiment, position and second embodiment of the second acoustic aperture 200 are distinguished to some extent: the second acoustic aperture 200 is arranged on the top of encapsulation cavity, namely be arranged on upper cover 21, the first acoustic aperture 100 is positioned at the relative both sides of microphone with the second acoustic aperture 200.
With reference to Figure 10 shows that the 6th embodiment of the present utility model, principle is identical with the second embodiment, and position and second embodiment of the second acoustic aperture 200 are distinguished to some extent: the second acoustic aperture 200 is arranged on the sidewall of encapsulation cavity, is namely arranged on sidewall 22.
MEMS microphone of the present utility model is provided with two acoustic aperture, be provided with at the second acoustic aperture place damping fin with reduce the acoustic pressure at the second acoustic aperture place and sound phase shift from the target sound source of the first acoustic aperture, it is identical with the amplitude of target sound source after the sound of target sound source is entered from the second acoustic aperture, thus increase target sound source to the effect acoustic pressure of vibrating diaphragm, MEMS chip produces the signal of telecommunication and exports under the acting in conjunction of two-way sound wave, achieves good directive property.
Structure of the present utility model, feature and action effect is described in detail above according to graphic shown embodiment; these are only preferred embodiment of the present utility model; but the utility model does not limit practical range with shown in drawing; every change done according to conception of the present utility model; or be revised as the Equivalent embodiments of equivalent variations; do not exceed yet specification with diagram contain spiritual time, all should in protection range of the present utility model.