MEMS acoustic sensor and method of use thereof

Abstract

The invention provides an MEMS acoustic sensor and a use method thereof, and the MEMS acoustic sensor comprises a packaging structure which is internally provided with a light generation assembly, an acoustic vibration device and a light sensing assembly. Wherein the acoustic vibration device is used for pickup and vibration; moreover, in the vibration process of the acoustic vibration device, light emitted by the light generation assembly is reflected by the acoustic vibration device and then irradiates different sensing positions on the light sensing assembly, and the light sensing assembly generates corresponding electric signals based on the irradiated sensing positions. The MEMS acoustic sensor can solve the problem that an existing MEMS acoustic sensor is low in sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acoustic device manufacturing, and more particularly to a MEMS acoustic sensor and a method for using the same. BACKGROUND

[0002] An acoustic sensor is a device that can convert sound signals into electrical signals, mainly used in acoustic devices such as microphones. Traditional acoustic sensors are mostly capacitive electret sensors. Such traditional acoustic sensors have large size and low sensitivity. With the increasing demand for product integration, traditional acoustic sensors cannot meet people's needs, and therefore MEMS (Micro-Electro-Mechanical System) acoustic sensors have emerged.

[0003] A MEMS acoustic sensor is a sensor manufactured using micro-electro-mechanical system (MEMS) technology. It uses semiconductor technology to manufacture electronic mechanical systems on a silicon wafer, senses sound, and converts it into an electrical signal. MEMS acoustic sensors have high precision and small size, and are widely used in various sound detection scenarios that require high sensitivity and small size.

[0004] The working principle of the existing MEMS acoustic sensor is that the vibration of the diaphragm picks up external sound signals. As the diaphragm vibrates, the distance between the diaphragm and the back plate changes, thereby generating different electrical signals to simulate external sound signals.

[0005] However, for the existing MEMS acoustic sensor with such a structure, foreign matter (such as debris, dust, etc.) is easily deposited between the diaphragm and the back plate during production and use. Due to the presence of these foreign matters, the capacitance between the diaphragm and the back plate changes, thereby reducing the sensitivity of the product. In addition, each device (such as the diaphragm and the back plate) of the MEMS acoustic sensor has internal stress, and during the release of the internal stress, the distance between the diaphragm and the back plate changes, thereby reducing the sensitivity of the product.

[0006] Based on the above technical problems, there is an urgent need for a solution that can significantly improve the sensitivity of the MEMS acoustic sensor. SUMMARY

[0007] In view of the above problems, the purpose of the present application is to provide a MEMS acoustic sensor and a method for using the same to solve the problem of low sensitivity of the existing MEMS acoustic sensor.

[0008] The MEMS acoustic sensor provided by the present application comprises a packaging structure, a light generating assembly, an acoustic vibration device, and a light sensing assembly are arranged in the packaging structure; wherein the acoustic vibration device is used for picking up sound and vibrating; and During the vibration of the acoustic vibration device, the light emitted by the light emitting assembly is reflected by the acoustic vibration device and irradiates on different sensing positions of the light sensing assembly, and the light sensing assembly generates corresponding electrical signals based on the irradiated sensing positions.

[0009] In addition, the acoustic vibration device comprises a support body and a vibrating diaphragm arranged on the support body, and the vibrating diaphragm is used for sound pickup and vibration.

[0010] In addition, the acoustic vibration device further comprises a reflecting layer arranged on the vibrating diaphragm, and the light emitted by the light emitting assembly is reflected by the reflecting layer and irradiates on the light sensing assembly.

[0011] In addition, a first cavity connected with the vibrating diaphragm is formed in the support body, an acoustic hole communicating with the outside is formed on the packaging structure, and a second cavity communicating with the acoustic hole is arranged in the packaging structure. The end of the first cavity away from the vibrating diaphragm is connected with the second cavity.

[0012] In addition, a filter screen is arranged in the first cavity and / or the second cavity.

[0013] In addition, the light emitting assembly comprises a light emitter, and the light emitter is used for emitting light to the acoustic vibration device.

[0014] In addition, the light emitting assembly comprises a light emitter and a reflecting element, the light emitter is used for sending light to the reflecting element, and the light emitted by the light emitter is reflected by the reflecting element and irradiates on the acoustic vibration device.

[0015] In addition, the packaging structure comprises a substrate, a side wall plate and a cover plate, the light emitter and the acoustic vibration device are arranged on the cover plate, and the light sensing assembly and the reflecting element are arranged on the substrate.

[0016] In addition, the light sensing assembly comprises at least two light receiving units, each light receiving unit is arranged at a corresponding sensing position, and each light receiving unit generates a corresponding electrical signal after being irradiated.

[0017] In addition, the acoustic sensing device further comprises a light emitting assembly and a light sensing assembly. The acoustic vibration device is used for picking up the sound to be measured, so that the acoustic vibration device vibrates. The light emitting component emits light to the acoustic vibration device, and the light is reflected by the acoustic vibration device and irradiates on the light sensing component. During the vibration of the acoustic vibration device, the light reflected by the acoustic vibration device irradiates on different sensing positions of the light sensing component, and the light sensing component generates corresponding electrical signals based on the irradiated sensing positions.

[0018] Compared with the prior art, the MEMS acoustic sensor and the use method thereof provided by the application have the following beneficial effects: By arranging the light emitting component, the acoustic vibration device and the light sensing component, the external sound signal can be sensed by using the optical device and the acoustic vibration device, compared with the prior art, the unstable hidden trouble (such as the change of the capacitance caused by the foreign matter and the internal stress of the device) in the working of the sensor can be effectively eliminated, and the sensitivity of the MEMS acoustic sensor is significantly improved; in addition, the structure of the diaphragm and the back plate can be omitted, and the bearing carrier of the foreign matter is further reduced.

[0019] To achieve the above and related objects, one or more aspects of the application include specific features that will be explained in detail below and particularly pointed out in the claims. The following description and the accompanying drawings detail certain illustrative aspects of the application. However, these aspects indicate only some of the ways in which the principles of the application can be employed. In addition, the application is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF DRAWINGS

[0020] Other objects and advantages of the application will become more apparent and readily appreciated from the following description, taken in connection with the accompanying drawings, with reference made to which: Figure 1 A first structure diagram of the MEMS acoustic sensor provided according to the embodiment of the application; Figure 2 A second structure diagram of the MEMS acoustic sensor provided according to the embodiment of the application; Reference signs: cover plate 1, side wall plate 2, base plate 3, light emitter 4, reflecting element 5, light sensing component 6, vibrating diaphragm 7, support body 8, reflecting layer 9, first cavity 10, acoustic hole 11, second cavity 12, light receiving unit 13, filter screen 14. DETAILED DESCRIPTION

[0021] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It can be evident, however, that embodiments can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.

[0022] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate structural member, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] Figure 1 A first structure of a MEMS acoustic sensor provided by an embodiment of the present application is shown, Figure 2 A second structure of a MEMS acoustic sensor provided by an embodiment of the present application is shown, in combination with Figure 1 With Figure 2 It can be seen that the MEMS acoustic sensor provided by the present application comprises a packaging structure for carrying internal devices, and the devices and chips used by the MEMS acoustic sensor are arranged in the packaging structure, and the packaging structure plays a role in protecting the internal devices. In order to realize the induction of external sound signals, a light generating assembly, a sound vibration device and a light sensing assembly 6 are arranged in the packaging structure; wherein the light generating assembly is used to generate light and emit to the sound vibration device, the sound vibration device is used to pick up sound and vibrate, and the light sensing assembly 6 is used to receive the reflected light of the sound vibration device and generate an electric signal, and the electric signal is finally output to an application end.

[0024] In actual use, when an external sound signal exists, the sound vibration device picks up the external sound signal through the sound hole 11 on the packaging structure and generates vibration. During the vibration of the sound vibration device, the light emitted by the light emitting assembly is reflected by the sound vibration device and irradiates different sensing positions on the light sensing assembly 6. Different sensing positions correspond to different vibration states (such as different amplitudes) of the sound vibration device, that is, correspond to the signal intensity of the external sound signal at different times. The light sensing assembly 6 generates an electrical signal corresponding to the external sound signal based on the sensing positions irradiated at different times, thereby achieving accurate sensing of the external sound signal.

[0025] In a specific embodiment of the present application, to realize the manufacture of the sound vibration device, the sound vibration device can include a support body 8 and a vibrating diaphragm 7 disposed on the support body 8. The vibrating diaphragm 7 is used to pick up external sound signals and generate vibrations. To improve the support performance of the support body 8 on the vibrating diaphragm 7, the support body 8 is preferably made of a rigid material, such as graphene or other rigid materials. To improve the pickup effect of the vibrating diaphragm 7 on sound signals, the vibrating diaphragm 7 is preferably made of a flexible film material.

[0026] In addition, to improve the reflection effect of the sound vibration device on the light emitted by the light emitting assembly, the sound vibration device can further include a reflection layer 9 disposed on the vibrating diaphragm 7. The reflection layer 9 vibrates with the vibrating diaphragm 7, and the light emitted by the light emitting assembly is reflected by the reflection layer 9 and irradiates on the light sensing assembly 6. The reflection layer 9 can be selected from reflectors with total reflection effect, such as mirrors, flexible reflective films, and reflective prisms, to improve the reflection effect of the sound vibration device on the light emitted by the light emitting assembly.

[0027] In another specific embodiment of the present application, a first cavity 10 connected to the vibrating diaphragm 7 can be formed in the support body 8, a sound hole 11 communicating with the outside can be formed on the packaging structure, and a second cavity 12 communicating with the sound hole 11 can be disposed in the packaging structure. The end of the first cavity 10 away from the vibrating diaphragm 7 communicates with the second cavity 12. Compared with the conventional scheme of directly disposing the sound hole 11 at the bottom of the front cavity below the diaphragm, the first cavity 10 and the second cavity 12 can be used to form a front cavity. The front cavity formed by the first cavity 10 and the second cavity 12 has a heterogeneous internal sound channel (such as an L-shaped channel as shown in Figure 1 and Figure 2 compared with the conventional straight internal sound channel, which can effectively improve the interception effect of foreign matter and prevent foreign matter entering through the sound hole 11 from reaching the vibrating diaphragm 7. Further, one or more filter screens 14 can be disposed in the front cavity formed by the first cavity 10 and the second cavity 12 to further intercept foreign matter.

[0028] In a specific embodiment of the present invention, the light generating component may include a light emitter 4 for emitting a light source. The light emitter 4 is used to emit light (light source) to the acoustic vibration device. The light emitted by the light emitter 4 is reflected by the acoustic vibration device and illuminates different sensing positions (e.g., on the light sensing component 6). Figure 2 (As shown). In another specific embodiment of the present invention, the light generating component may also include a light emitter 4 and a reflector 5. The light emitter 4 is used to send light to the reflector 5. The light emitted by the light emitter 4 is reflected by the reflector 5 and then irradiates the acoustic vibration device. After being reflected by the acoustic vibration device, the light will irradiate different sensing positions on the light sensing component 6 (e.g., as shown). Figure 1 (as shown); wherein, the reflector 5 can be a reflective device with total internal reflection effect, such as a reflector or a reflective prism, to improve the reflection effect of the reflector 5 on the light emitted by the light emitter 4.

[0029] It should be noted that the packaging structure of the MEMS acoustic sensor provided by this invention can adopt a three-layer plate structure design. For example, the packaging structure may include a substrate 3, a sidewall plate 2 disposed on the substrate 3, and a cover plate 1 disposed on the sidewall plate 2 away from the substrate 3. For the three-layer plate structure packaging structure, the light emitter 4 can be disposed on the same sidewall plate as the acoustic vibration device (e.g., ...). Figure 1 The light emitted by the light emitter 4 is not directly illuminating the acoustic vibration device, as shown in the diagram, and can also be installed on the side wall plate 2 or the substrate 3 as needed. Therefore, it is necessary to install the light on other wall plates (such as...). Figure 1 On the substrate 3 shown, a reflector 5 can also be provided on the side wall plate 2 as needed to reflect the light emitted by the light emitter 4 onto the acoustic vibration device; the light sensing component 6 can be provided on the substrate 3 or the side wall plate 2 as needed to receive the light reflected from the acoustic vibration device.

[0030] Of course, the light emitter 4 can also be mounted on a different panel than the acoustic vibration device (e.g., the acoustic vibration device is mounted on the cover plate 1, and the light emitter 4 is mounted on the substrate 3). In this case, the light emitted by the light emitter 4 can directly illuminate the acoustic vibration device, thus eliminating the need for the reflector 5 (e.g., ...). Figure 2 (as shown); the light sensing component 6 can be disposed on the substrate 3 or the side wall plate 2 as needed to receive light reflected from the acoustic vibration device.

[0031] It should be further explained here that the light emitter 4, the acoustic vibration device, and the light sensing component 6 can be set on any wall panel (such as the substrate 3, the side wall panel 2, and the cover plate 1) as needed. In the actual design process, the corresponding optical path requirements can be met simply by controlling the number and position of the reflectors 5.

[0032] To realize the sensing of the light reflected by the acoustic vibration device by the light sensing assembly 6 and generate the corresponding electrical signal, the light sensing assembly 6 can include a light receiving module and a light signal processing module, and a plurality of (at least two) different light receiving units 13 are distributed on the light receiving module, and each light receiving unit 13 is arranged at a corresponding sensing position, and each light receiving unit 13 corresponds to a different light power. In actual use, during the vibration of the acoustic vibration device, the light emitted by the light emitting assembly is reflected by the acoustic vibration device and irradiates on the different light receiving units 13 on the light sensing assembly 6, and each light receiving unit 13 generates a corresponding light power signal after being irradiated, and the different light power signals are amplified, shaped, converted and the like through the cooperation of the light receiving unit 13 and the light signal processing module, so as to convert the light signal (light reflected by the acoustic vibration device) received by the light sensing assembly 6 into a corresponding electrical signal, and finally output to the corresponding application end.

[0033] It should be noted that the light receiving units 13 can be distributed in a matrix on the light receiving module, and through this design, the signal intensity of the sound signal to be measured at different moments can be better represented by the light receiving units 13.

[0034] To further illustrate the working principle of the MEMS acoustic sensor provided by the application, the application further provides a use method of the acoustic sensor, and the use method comprises the following steps: The sound signal to be measured from the outside enters the front cavity inside the packaging structure through the sound hole 11, and the sound signal to be measured is picked up by the acoustic vibration device to make the acoustic vibration device vibrate; The light emitting assembly emits light to the acoustic vibration device, and the light is irradiated on the light sensing assembly 6 after being reflected by the acoustic vibration device, and the light sensing assembly 6 generates a corresponding electrical signal based on the received light; wherein, during the vibration of the acoustic vibration device, the light is irradiated on different sensing positions of the light sensing assembly 6 after being reflected by the acoustic vibration device, and the light sensing assembly 6 generates a corresponding electrical signal based on the irradiated sensing position.

[0035] As can be seen from the above specific embodiments, the MEMS acoustic sensor and the use method thereof provided by the application at least have the following advantages: 1. By arranging the light emitting assembly, the acoustic vibration device and the light sensing assembly, the external sound signal can be sensed by using the optical device in cooperation with the acoustic vibration device, compared with the existing MEMS acoustic sensor, the unstable hidden danger (such as the change of capacitance caused by foreign matter and internal stress of the device) in the working of the sensor can be effectively eliminated, and the sensitivity of the MEMS acoustic sensor can be significantly improved; 2. The structure of the diaphragm and the back plate can be omitted, and the bearing carrier of foreign matter can be further reduced; 3. By setting up a first cavity and a second cavity, the front cavity structure is modified. The front cavity with an irregular internal sound channel can effectively improve the interception effect of foreign objects and prevent foreign objects entering through the sound hole from reaching the vibrating diaphragm. 4. By installing one or more filters in the front cavity formed by the first cavity and the second cavity, foreign objects can be further intercepted through the filters; 5. By setting reflectors at appropriate locations, the light emitter, acoustic vibration device, and light sensing component can be flexibly set on any wall panel (such as substrate, side wall panel, and cover plate) to meet different assembly requirements.

[0036] As per the above reference Figures 1 to 2 The MEMS acoustic sensor and its usage method according to the present invention are described by way of example. However, those skilled in the art will understand that various modifications can be made to the MEMS acoustic sensor and its usage method proposed in the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. A MEMS acoustic sensor comprising a package structure, characterized in that, A light generating component, an acoustic vibration device and a light sensing component are arranged in the packaging structure; the acoustic vibration device is used for picking up sound and generating vibration; and, During the vibration process of the acoustic vibration device, the light emitted by the light generating component is reflected by the acoustic vibration device and then irradiates on different sensing positions of the light sensing component, and the light sensing component generates corresponding electrical signals based on the irradiated sensing positions. 2.The MEMS acoustic sensor of claim 1, wherein The acoustic vibration device comprises a support body and a vibrating diaphragm arranged on the support body, and the vibrating diaphragm is used for picking up sound and generating vibration. 3.The MEMS acoustic sensor of claim 2, wherein The acoustic vibration device further comprises a reflecting layer arranged on the vibrating diaphragm, and the light emitted by the light generating component is reflected by the reflecting layer and then irradiates on the light sensing component. 4.The MEMS acoustic sensor of claim 2, wherein A first cavity connected with the vibrating diaphragm is formed in the support body, an acoustic hole communicating with the outside is formed on the packaging structure, and a second cavity communicating with the acoustic hole is arranged in the packaging structure; wherein The first cavity is connected with the second cavity at an end away from the vibrating diaphragm. 5.The MEMS acoustic sensor of claim 4, wherein A filter screen is arranged in the first cavity and / or the second cavity. 6.The MEMS acoustic sensor of claim 1, wherein The light generating component comprises a light emitter, and the light emitter is used for emitting light to the acoustic vibration device. 7.The MEMS acoustic sensor of claim 1, wherein The light generating component comprises a light emitter and a reflecting element, the light emitter is used for sending light to the reflecting element, and the light emitted by the light emitter is reflected by the reflecting element and then irradiates on the acoustic vibration device. 8.The MEMS acoustic sensor of claim 7, wherein The packaging structure comprises a substrate, a side wall plate and a cover plate; the light emitter and the acoustic vibration device are arranged on the cover plate, and the light sensing component and the reflecting element are arranged on the substrate. 9.The MEMS acoustic sensor of claim 1, wherein The light sensing component comprises at least two light receiving units, each light receiving unit is arranged at a corresponding sensing position, and each light receiving unit generates a corresponding electrical signal after being irradiated.

10. A method of using a MEMS acoustic sensor as claimed in any one of claims 1 to 9, characterized in that, including: The acoustic vibration device picks up a to-be-measured sound signal so that the acoustic vibration device generates vibration; The light generating component emits light to the acoustic vibration device, and the light is reflected by the acoustic vibration device and then irradiates on the light sensing component; wherein During the vibration process of the acoustic vibration device, the light is reflected by the acoustic vibration device and then irradiates on different sensing positions of the light sensing component, and the light sensing component generates corresponding electrical signals based on the irradiated sensing positions.

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