Microphone chip and microphone

Abstract

The present application relates to the technical field of optical microphone, and more particularly to a microphone chip and a microphone. The microphone chip of the present application comprises: a substrate, which is provided with an inner cavity; a diaphragm, which is supported on the substrate, and comprises an inner membrane part and an outer membrane part connected with the inner membrane part, the diaphragm is supported on the substrate through the outer membrane part, and the inner membrane part is arranged opposite to the inner cavity; and a limiting piece, which is supported on the substrate and located on opposite sides of the diaphragm along the vibration direction and spaced from the diaphragm, and is used for limiting the amplitude of the inner membrane part. When the inner membrane part moves to a certain stroke, the limiting piece can limit the continuous movement of the inner membrane part, so as to reduce the risk of damage caused by the excessive vibration stroke of the diaphragm under high sound pressure.

Description

[Technical Field]

[0001] This invention relates to the field of optical microphone technology, and more particularly to a microphone chip and a microphone. [Background Technology]

[0002] Traditional microphones are based on capacitors, where the diaphragm vibrates with the sound waves and generates voltage changes when the distance between the capacitor plates changes, thus achieving sound-to-electric conversion.

[0003] An optical microphone typically comprises an optoelectronic module, an application-specific integrated circuit (ASIC), and a microelectromechanical system (MEMS). The optoelectronic module emits light into the MEMS and receives light reflected by it. When sound waves drive the diaphragm of the MEMS, the diaphragm vibrates slightly, altering the intensity and phase of the light reflected back to the optoelectronic module. The optoelectronic module converts the intensity and phase signals of the reflected light into electrical signals, which are then transmitted to the ASIC, thus achieving the conversion from acoustic to optical and then to electrical signals.

[0004] When a microelectromechanical system (MEMS) is subjected to a signal with a high voltage difference, the diaphragm may deflect significantly, resulting in extremely high stress and damage to the diaphragm. [Summary of the Invention]

[0005] The purpose of this invention is to provide a microphone chip and microphone that reduces the risk of damage to the diaphragm when it has a large vibration stroke.

[0006] This invention provides a microphone chip, the microphone chip comprising:

[0007] A substrate having an internal cavity;

[0008] A diaphragm, at least partially supported on the substrate, and at least a portion of the inner diaphragm portion of the diaphragm is disposed opposite to the inner cavity;

[0009] A limiting member is supported on the substrate and located on opposite sides of the diaphragm along the vibration direction and spaced apart from the diaphragm. The limiting member is used to limit the amplitude of the diaphragm.

[0010] In one possible design, the limiting member includes a first limiting portion and a second limiting portion located on opposite sides of the diaphragm along the vibration direction;

[0011] The first limiting portion and the second limiting portion extend along the vibration direction perpendicular to the diaphragm, and their projections along the vibration direction of the diaphragm are at least partially located in the inner cavity;

[0012] Along the vibration direction of the diaphragm, at least a portion of the diaphragm facing the inner cavity is located between the first limiting portion and the second limiting portion.

[0013] In one possible design, the diaphragm includes an inner diaphragm portion and an outer diaphragm portion connected to the inner diaphragm portion. The inner diaphragm portion and the outer diaphragm portion are integrally formed or separately formed. The diaphragm is supported on the substrate via the outer diaphragm portion. The inner diaphragm portion is disposed opposite to the inner cavity. At least a portion of the inner diaphragm portion is located between the first limiting portion and the second limiting portion.

[0014] In one possible design, the projections of the first limiting portion and the second limiting portion onto the inner membrane portion along the vibration direction of the diaphragm only cover the edge portion of the inner membrane portion.

[0015] In one possible design, along the thickness direction of the microphone chip, during diaphragm vibration, the inner diaphragm portion abuts against the edges of the first and second limiting portions near the inner cavity to limit the amplitude of the diaphragm. In another possible design, the microphone chip further includes a fixing member supported on the substrate and connected between the first and second limiting portions, the fixing member connecting the edges of the first and second limiting portions away from the inner diaphragm portion, and at least a portion of the outer diaphragm portion is fixed to the fixing member.

[0016] In one possible design, the fastener includes a first fastening portion and a second fastening portion stacked along the vibration direction of the diaphragm, with the outer diaphragm portion at least partially sandwiched between the first fastening portion and the second fastening portion.

[0017] In one possible design, the stiffness of the inner membrane portion is greater than that of the outer membrane portion, the outer membrane portion is fixed to the fixing member only at its edge away from the inner membrane portion, and the diaphragm is supported on the substrate only by the outer membrane portion.

[0018] In one possible design, the diaphragm further includes a connecting portion that connects the inner diaphragm portion and the outer diaphragm portion;

[0019] The stiffness of the connecting part is less than that of the inner membrane part.

[0020] In one possible design, the connecting part is an elastic element or a plurality of sequentially stacked pleats.

[0021] This application also provides a microphone, the microphone comprising:

[0022] A microphone chip, wherein the microphone chip is the microphone chip described above;

[0023] The optoelectronic module is capable of emitting a light beam toward the diaphragm along the vibration direction of the diaphragm and receiving the light beam reflected by the diaphragm, so as to convert the optical signal into an electrical signal.

[0024] An integrated circuit module is used to receive electrical signals transmitted by the optoelectronic module;

[0025] When the diaphragm vibrates under sound pressure, the intensity and phase of the light beam reflected by the diaphragm change. The integrated circuit module obtains the displacement of the diaphragm by analyzing the electrical signals emitted and received by the photoelectric module.

[0026] The beneficial effect of the present invention is that when the inner diaphragm moves to a certain stroke under a high sound pressure level, the limiting member can restrict the inner diaphragm from continuing to move, thereby reducing the risk of damage caused by excessive vibration stroke of the diaphragm under high sound pressure level. [Attached Image Description]

[0027] Figure 1 This is a schematic diagram of the microphone provided by the present invention in use.

[0028] Figure 2 This is a schematic diagram of the microphone chip provided by the present invention in a specific embodiment;

[0029] Figure 3 This is a schematic diagram of the microphone chip provided by the present invention in another specific embodiment.

[0030] [Attached image labels]

[0031] 1-Microphone chip;

[0032] 11-Base;

[0033] 111-Inner cavity;

[0034] 12-Diaphragm;

[0035] 121 - Endometrial portion;

[0036] 122 - Connecting part;

[0037] 123 - Outer membrane portion;

[0038] 13-Limiting component;

[0039] 131 - First limiting part;

[0040] 132 - Second limiting part;

[0041] 14-Factor;

[0042] 141-First fixing part;

[0043] 142 - Second fixing part;

[0044] 2-Optical module.

Detailed Implementation Methods

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] This invention provides a microphone, which can be an optical microphone. Figure 1 As shown, the microphone includes a microphone chip 1, an optoelectronic module 2, and an integrated circuit module (not shown). The integrated circuit module is electrically connected to the microphone chip 1 and the optoelectronic module 2. The microphone chip 1 has a diaphragm 12, which can vibrate in response to sound pressure. The optoelectronic module 2 can emit a light beam towards the diaphragm 12 and receive the light beam reflected by the diaphragm 12, thus converting the light signal into an electrical signal. The integrated circuit module can receive the electrical signal transmitted by the optoelectronic module 2. When the microphone is used, sound can drive the diaphragm 12 to vibrate, and the optoelectronic module 2 emits a light beam towards the diaphragm 12. Due to the vibration of the diaphragm 12, the intensity and phase of the light beam reflected by the diaphragm 12 change. The optoelectronic module 2 converts the intensity and phase signals of the reflected light into electrical signals and transmits the electrical signals to the integrated circuit module, thereby realizing the conversion from sound signal to light signal and then to electrical signal. The integrated circuit module obtains the displacement of the diaphragm 12 by analyzing the electrical signals emitted and received by the optoelectronic module 2.

[0047] The optoelectronic module 2 includes a laser and a sensor with a power-generating diode. The laser and sensor are located on the same side of the diaphragm 12. The laser emits a light beam toward the diaphragm 12, and the sensor receives the light beam emitted by the laser and reflected by the diaphragm 12. The integrated circuit module includes electronic circuitry that constitutes a control or central processing unit and is configured to drive, control, and implement the necessary actions of the relevant electronic and optoelectronic components in the system.

[0048] Specifically, such as Figure 2 and Figure 3 As shown, the microphone chip 1 includes a substrate 11, a diaphragm 12, and a limiting member 13. The diaphragm 12 is supported on the substrate 11. The diaphragm 12 includes an inner diaphragm portion 121 and an outer diaphragm portion 123 connected to each other. The diaphragm 12 is supported on the substrate 11 via the outer diaphragm portion 123. The substrate 11 has an inner cavity 111, and the inner diaphragm portion 121 is disposed opposite to the inner cavity 111. The limiting member 13 is supported on the substrate 11 and is located on opposite sides of the diaphragm 12 along the vibration direction and spaced apart from the diaphragm 12. The limiting member 13 is used to limit the amplitude of the inner diaphragm portion 121.

[0049] When the diaphragm 12 moves in response to the sound pressure, the length of the inner cavity 111 changes, which changes the light intensity of the beam, changes the angle of the reflected light, and changes the phase of the beam. In turn, the light signal corresponding to the sound signal is collected, and the light signal is converted into an electrical signal for further analysis.

[0050] In this invention, along the vibration direction of the diaphragm 12, the diaphragm 12 is spaced apart from the limiting members 13 located on both sides, so that the diaphragm 12 has a certain amount of movement before the limiting members 13 restrict its continued movement. When the inner diaphragm portion 121 moves to a certain stroke, at least a portion of the inner diaphragm portion 121 comes into contact with the limiting member 13, so that the limiting member 13 can restrict the inner diaphragm portion 121 from continuing to move, thereby limiting the amplitude of the inner diaphragm portion 121 and reducing the risk of damage caused by excessive vibration stroke of the diaphragm 12 under high sound pressure.

[0051] Specifically, such as Figure 2 and Figure 3 As shown, the limiting member 13 includes a first limiting portion 131 and a second limiting portion 132 located on opposite sides of the diaphragm 12 along the vibration direction. The first limiting portion 131 and the second limiting portion 132 extend perpendicular to the vibration direction of the diaphragm 12, and their projections along the vibration direction of the diaphragm 12 are at least partially located in the inner cavity 111. Along the vibration direction of the diaphragm 12, the inner diaphragm portion 121 is located between the first limiting portion 131 and the second limiting portion 132. Based on the projections along the vibration direction of the diaphragm 12, at least a portion of the first limiting portion 131 and at least a portion of the second limiting portion 132 are located in the inner cavity 111, and the first limiting portion 131 and the second limiting portion 132 do not extend to the middle portion of the inner diaphragm portion 121. After the inner diaphragm portion 121 moves downward to abut against the first limiting portion 131, the first limiting portion 131 restricts the inner diaphragm portion 121 from moving further downward. After the inner diaphragm portion 121 moves upward to abut against the second limiting portion 132, the second limiting portion 132 restricts the inner diaphragm portion 121 from moving further upward, thereby limiting the amplitude of the diaphragm 12. Furthermore, the first limiting portion 131 and the second limiting portion 132 do not extend to the middle portion of the inner diaphragm portion 121; that is, the first limiting portion 131 and the second limiting portion 132 do not completely cover the inner diaphragm portion 121, allowing the inner diaphragm portion 121 to increase its vibration stroke in response to pressure load. Compared to a backplate structure that completely covers the inner diaphragm portion 121, this invention eliminates associated damping, thereby reducing microphone noise.

[0052] More specifically, the projections of the first limiting portion 131 and the second limiting portion 132 onto the inner diaphragm portion 121 along the vibration direction of the diaphragm 12 only cover the edge portion of the inner diaphragm portion 121. The inner edges of the first limiting portion 131 and the inner edges of the second limiting portion 132 are positioned opposite to the edge portion of the inner diaphragm portion 121. The innermost edge of the limiting member 13 abuts against the edge portion of the inner diaphragm portion 121, thereby limiting further upward or downward movement of the inner diaphragm portion 121 and reducing the risk of damage to the diaphragm 12 due to excessive amplitude.

[0053] Furthermore, such as Figure 2 and Figure 3As shown, there is a gap between the edge portion of the inner membrane portion 121 and the first limiting portion 131 and the second limiting portion 132, so that the inner membrane portion 121 moves a certain distance and then comes into contact with the first limiting portion 131 and the second limiting portion 132, ensuring that the inner membrane portion 121 has a certain amount of movement before coming into contact with the first limiting portion 131 and the second limiting portion 132.

[0054] like Figure 2 and Figure 3 As shown, in some embodiments, the microphone chip 1 further includes a fixing member 14 supported on the substrate 11 and connected between the first limiting portion 131 and the second limiting portion 132. The fixing member 14 connects the edges of the first limiting portion 131 and the second limiting portion 132 away from the inner diaphragm portion 121, and at least a portion of the outer diaphragm portion 123 is fixed to the fixing member 14. In this invention, the edge portion of the outer diaphragm portion 123 can be fixed between the fixing members 14, reducing the fixing portion of the diaphragm 12 and improving the sensitivity of the diaphragm 12.

[0055] The fixing member 14 includes a first fixing part 141 and a second fixing part 142 stacked along the vibration direction of the diaphragm 12. The outer diaphragm part 123 is at least partially sandwiched between the first fixing part 141 and the second fixing part 142. Specifically, the first fixing part 141 is located between the outer diaphragm part 123 and the first limiting part 131, and the second fixing part 142 is located between the outer diaphragm part 123 and the second limiting part 132. The support of the first fixing part 141 on the first limiting part 131 forms the gap between the inner diaphragm part 121 and the first limiting part 131, and the support of the second fixing part 142 on the second limiting part 132 forms the gap between the inner diaphragm part 121 and the second limiting part 132. This allows the inner diaphragm part 121 to have a certain amount of movement before it comes into contact with the first limiting part 131 and the second limiting part 132 during the vibration process, and the inner diaphragm part 121 can vibrate in response to pressure load.

[0056] In some embodiments, the stiffness of the inner diaphragm portion 121 is greater than that of the outer diaphragm portion 123, giving the diaphragm 12 a middle portion with higher stiffness and an outer portion with lower stiffness. This allows the diaphragm 12 to withstand larger sound pressure loads and reduces the risk of damage to the diaphragm 12. Furthermore, the inner diaphragm portion 121 has a larger amplitude and higher sensitivity. Only the edge portion of the outer diaphragm portion 123 away from the inner diaphragm portion 121 is fixed to the fixing member 14, and the diaphragm 12 is supported on the substrate 11 only by the outer diaphragm portion 123. By fixing the minimum length of the diaphragm 12 along its periphery by the fixing member 14, the vibration stroke of the inner diaphragm portion 121 is increased, thereby improving the mechanical sensitivity of the diaphragm 12.

[0057] In some embodiments, the diaphragm further includes a connecting portion 122, which connects the inner diaphragm portion 121 and the outer diaphragm portion 123. The stiffness of the connecting portion 122 is less than the stiffness of the inner diaphragm portion 121. The connecting portion 122 is provided between the outer diaphragm portion 123 and the inner diaphragm portion 121, and the connecting portion 122 can form a circle around the circumference of the diaphragm 12. By setting the stiffness of the connecting portion 122 to be less than that of the inner diaphragm portion 121, the stiffness of the diaphragm 12 is reduced, allowing the diaphragm 12 to release stress through deformation, thereby improving the microphone's sensitivity.

[0058] like Figure 2 As shown, in some embodiments, the connecting portion 122 is an elastic element. When the inner membrane portion 121 is working, the inner membrane portion 121 can overcome the elastic force of the elastic element and stretch it. When the inner membrane portion 121 stops working, the elastic element can return to its initial position through its own elastic force.

[0059] The elastic element can be a spring, with one end connected to the outer edge of the inner diaphragm 121 and the other end connected to the inner edge of the outer diaphragm 123. Because the spring has elasticity, it can increase the vibration stroke of the inner diaphragm 121 and improve the mechanical sensitivity of the diaphragm 12, thereby enabling the sensing of a wider range of sound signals.

[0060] like Figure 3 As shown, in some embodiments, the connecting portion 122 consists of multiple stacked pleats. When the inner membrane portion 121 is working, it can cause the multiple stacked pleats to unfold. When the inner membrane portion 121 stops working, the multiple pleats can return to their stacked state.

[0061] The pleated portion can be integrated with the inner diaphragm portion 121 and the outer diaphragm portion 123, forming the pleated portion by stacking the portion between the inner diaphragm portion 121 and the outer diaphragm portion 123. This pleated portion can return to its initial state after being stretched and released. Because the pleated portion is stretchable, it can increase the vibration stroke of the inner diaphragm portion 121, improve the mechanical sensitivity of the diaphragm 12, and thus sense a wider range of sound signals.

[0062] The connecting part 122, the inner membrane part 121, and the outer membrane part 123 can be an integral structure, making the connecting part 122 the same material as the inner membrane part 121 and the outer membrane part 123, which facilitates manufacturing. The diaphragm 12 can be made of a single material or multiple materials, such as monocrystalline silicon, silicon nitride, silicon oxide, polycrystalline silicon, polyimide, or any combination thereof.

[0063] By providing a connecting part 122 and a limiting member 13, the present invention enables the diaphragm 12 to have high mechanical sensitivity while reducing the risk of damage to the diaphragm 12 due to excessive amplitude under high sound pressure.

[0064] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A microphone chip, characterized in that, The microphone chip includes: A substrate having an internal cavity; A diaphragm, at least partially supported on the substrate, and at least partially disposed opposite to the inner cavity; A limiting member is supported on the substrate and located on opposite sides of the diaphragm along the vibration direction and spaced apart from the diaphragm. The limiting member is used to limit the amplitude of the diaphragm. The limiting member includes a first limiting portion and a second limiting portion located on opposite sides of the diaphragm along the vibration direction; The first limiting portion and the second limiting portion extend along the vibration direction perpendicular to the diaphragm, and their projections along the vibration direction of the diaphragm are at least partially located in the inner cavity; Along the vibration direction of the diaphragm, at least a portion of the diaphragm facing the inner cavity is located between the first limiting portion and the second limiting portion; The diaphragm includes an inner diaphragm portion and an outer diaphragm portion connected to the inner diaphragm portion. The diaphragm is supported on the substrate via the outer diaphragm portion. The inner diaphragm portion is disposed opposite to the inner cavity. At least a portion of the inner diaphragm portion is located between the first limiting portion and the second limiting portion. The stiffness of the inner diaphragm portion is greater than the stiffness of the outer diaphragm portion. A fixing member is provided along the vibration direction of the diaphragm. The fixing member is disposed between the first limiting part and the diaphragm and between the second limiting part and the diaphragm. The fixing member connects the edges of the first limiting part and the second limiting part away from the inner diaphragm part. At least a portion of the outer diaphragm part is fixed to the fixing member.

2. The microphone chip according to claim 1, characterized in that: The inner membrane portion and the outer membrane portion are integrally formed or separately formed.

3. The microphone chip according to claim 1, characterized in that: The projections of the first limiting portion and the second limiting portion onto the inner membrane portion along the vibration direction of the diaphragm only cover the edge portion of the inner membrane portion.

4. The microphone chip according to claim 3, characterized in that: During the vibration of the diaphragm, the inner diaphragm portion abuts against the edges of the first limiting portion and the second limiting portion near the inner cavity to limit the amplitude of the diaphragm.

5. The microphone chip according to claim 1, characterized in that: The fixing member includes a first fixing part and a second fixing part stacked along the vibration direction of the diaphragm, and the outer diaphragm part is at least partially sandwiched between the first fixing part and the second fixing part.

6. The microphone chip according to claim 5, characterized in that: The outer membrane portion is fixed to the fixing member only at the edge away from the inner membrane portion, and the diaphragm is supported on the substrate only by the outer membrane portion.

7. The microphone chip according to claim 1, characterized in that: The diaphragm further includes a connecting portion, which connects the inner diaphragm portion and the outer diaphragm portion; The stiffness of the connecting part is less than that of the inner membrane part.

8. The microphone chip according to claim 7, characterized in that: The connecting part is an elastic element or multiple pleats stacked sequentially.

9. A microphone, characterized in that, The microphone includes: A microphone chip, wherein the microphone chip is the microphone chip according to any one of claims 1 to 8; The optoelectronic module is capable of emitting a light beam toward the diaphragm along the vibration direction of the diaphragm and receiving the light beam reflected by the diaphragm, so as to convert the optical signal into an electrical signal. An integrated circuit module is used to receive electrical signals transmitted by the optoelectronic module; When the diaphragm vibrates under sound pressure, the intensity and phase of the light beam reflected by the diaphragm change. The integrated circuit module obtains the displacement of the diaphragm by analyzing the electrical signals emitted and received by the photoelectric module.

Images