CN201426177Y - mems microphone - Google Patents

Abstract

The utility model relates to the field of microphones, specifically a MEMS microphone. The MEMS chip is arranged on an upper cover plate with a sound inlet, and the concave sound cavity on the chip is corresponding to the sound inlet, and is connected with it, so that the sound energy can flow from the The back of the MEMS diaphragm acts on the MEMS chip, which undoubtedly expands the back acoustic cavity of the MEMS chip, which is conducive to improving the frequency response performance and signal-to-noise ratio of the microphone, and improving the overall performance of the device.

Description

The MEMS microphone

[technical field]

The utility model relates to the microphone field, specifically refers to a kind of MEMS microphone.

[background technology]

Development along with wireless telecommunications, Global Mobile Phone Users is more and more, the user not only is satisfied with conversation to the requirement of mobile phone, and want high-quality communication effect can be provided, especially at present the development of mobile multimedia technology, requirement is strengthened the directive property and the noise reduction capability of picking up sound, and the microphone of mobile phone is as the voice pick device of mobile phone, and its design quality directly influences speech quality.

Use at present more and microphone better performances is MEMS (Micro-Electro-Mechanical-System Microphone) microphone, as shown in Figure 1; It comprises the band sound hole 11 ~ upper cover plate 10 ~, a shell wall 20 ~, around and support upper cover plate 10 ~; One substrate 30 ~, be equipped with on it MEMS chip 50 of mutual electrical connection ~, the application-specific integrated circuit ASIC chip 40 of interior integrated preamplifier ~ and other passive components, described substrate 30 ~ supports shell wall 20 ~ with upper cover plate 10 ~; MEMS chip 50 ~ be attached to substrate 30 ~ on, thereby MEMS chip 50 ~ on a depressed part and substrate 30-basal plane between form the back operatic tunes 51 of microphone ~.Above-mentioned structure that provides a kind of silica-based microphone, the MEMS chip 50 of this design ~ and substrate 30 ~ between form the back operatic tunes 51 of microphone ~ the space very limited, also very little to the contribution that performance improves, this will certainly be minimal the frequency response performance of change MEMS chip 50 ~ upper sensor self, be unfavorable for improving signal to noise ratio, in addition acoustic energy is directly incident on the silicon base vibrative membrane sheet, also can be subjected to ambient light, electromagnetic interference simultaneously, and this will influence the performance and the life-span of microphone.

[utility model content]

It is low that the purpose of this utility model is to solve microphone self frequency response performance, the problem that signal to noise ratio is little, and a kind of MEMS microphone that sound is advanced at the back side that increases is proposed.

A kind of MEMS microphone, comprise the upper cover plate of being with sound hole, one around and support the shell wall, a substrate of upper cover plate, the application-specific integrated circuit ASIC chip be installed on it, described base plate supports shell wall and upper cover plate, and be provided with the MEMS chip in the cavity of being formed, wherein said MEMS chip placing is on upper cover plate, form a depression operatic tunes between MEMS chip and the upper cover plate real estate, this depression operatic tunes is over against the sound hole of upper cover plate, and perforation with it.

Preferably, be provided with the elargol of the signal of telecommunication between conduction asic chip and the MEMS chip between described upper cover plate and the substrate.

The utility model MEMS microphone, the MEMS chip is located on the upper cover plate that has sound hole, and the depression operatic tunes on the chip is over against answering sound hole, connect with it, acoustic energy acts on the MEMS chip from the back side of MEMS diaphragm like this, enlarge the back operatic tunes of MEMS chip undoubtedly, helped improving the frequency response performance and the signal to noise ratio of microphone, improved the device overall performance.

[description of drawings]

Fig. 1 is the cross-sectional schematic of prior art MEMS microphone;

Fig. 2 is the cross-sectional schematic of the utility model MEMS microphone.

[embodiment]

Describe concrete structure of the present utility model in detail below in conjunction with accompanying drawing.

The utility model MEMS microphone is mainly used on the mobile phone, receives acoustical signal and acoustical signal is converted into the signal of telecommunication.As shown in Figure 2, be the utility model one preferred embodiment, it comprise a band sound hole 11 upper cover plate 10, a shell wall 20, around and support upper cover plate 10; One substrate 30, described substrate 30 supports shell wall 20 and upper cover plate 10, and substrate 30 is combined into a cube cavity with shell wall 20, upper cover plate 10; At cavity inside, application-specific integrated circuit ASIC chip 40 is installed on the substrate 30, and MEMS chip 50 is placed on the upper cover plate 10, forms a depression operatic tunes 51 between MEMS chip 50 and upper cover plate 10 real estates, this depression operatic tunes 51 is over against the sound hole 11 of upper cover plate 10, and connects with sound hole 11.Acoustic energy acts on the MEMS chip from the back side of MEMS diaphragm, just proceed to the depression operatic tunes 51 from sound hole 11, arrive diaphragm again, this has enlarged the back operatic tunes 52 of MEMS chip undoubtedly, clearly, the space of this back operatic tunes 52 obviously greater than the back operatic tunes 51 of the described microphone of Fig. 1 ~ the space, then this back operatic tunes 52 is not subjected to the restriction of substrate 300, the back operatic tunes 52 that increases makes Frequency Response and the open circuit sensitivity after the mems microphone encapsulation best, help improving the signal to noise ratio of microphone, improve the device overall performance.

In addition, upper cover plate 10 is that the PCB material is made, can be in last wiring, and the signal of telecommunication between upper cover plate 10 and the substrate 30 is connected by a some elargol 60, thereby asic chip 40 and 50 electric connections of MEMS chip are got up, and is simple and reliable.

The above only is a better embodiment of the present utility model; protection range of the present utility model does not exceed with above-mentioned execution mode; as long as the equivalence that those of ordinary skills do according to the utility model institute disclosure is modified or changed, all should include in the protection range of putting down in writing in claims.

Claims (2)

1. A kind of MEMS microphone, comprises the upper cover plate that takes into sound hole, one surrounds and supports the housing wall of upper cover plate, a substrate, on which application-specific integrated circuit ASIC chip is installed, described substrate support housing wall and upper cover board, and a MEMS chip is provided in the formed cavity, which is characterized in that: the MEMS chip is placed on the upper cover, and a concave acoustic cavity is formed between the MEMS chip and the upper cover substrate, and the concave acoustic cavity is facing The sound inlet hole of the upper cover plate is connected with it. 2 . The MEMS microphone according to claim 1 , wherein a silver glue is provided between the upper cover plate and the substrate to conduct electrical signals between the ASIC chip and the MEMS chip. 3 .

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