Microphone chip and microphone

Abstract

The present invention proposes a microphone chip, which includes a substrate with a back cavity and a capacitor system arranged on the substrate, wherein the capacitor system includes a back plate and a diaphragm arranged relatively spaced apart. The characteristic is that the microphone chip also includes a piezoelectric piece attached to the diaphragm, and the piezoelectric piece generates an electrical signal as the diaphragm vibrates to control the energy supply of the capacitor system. The piezoelectric piece attached to the diaphragm can vibrate along with the diaphragm to generate an electrical signal, thereby controlling the energy supply to the capacitor system of the microphone chip. In this way, when there is no signal input, the microphone chip provided by the present invention can be in standby mode with very low power consumption, thereby achieving the purpose of reducing power consumption.

Description

Technical field

[0002] The present invention relates to a sensor and applications thereof, and in particular to a microphone chip and a microphone using the microphone chip. [Background Technology]

[0004] The microphone chip is the core component of the microphone. The microphone chips provided by the existing technology are mostly set as a capacitive sensing structure, which includes a substrate and a capacitor system consisting of a diaphragm and a backplate fixed on the substrate. A higher bias voltage is applied to the capacitor system to form a flat capacitor. When the external sound wave vibrates, the diaphragm vibrates, which in turn causes the capacitor system to generate an electrical signal output.

[0005] However, regardless of whether there is an external sound wave signal input, the microphone chip always needs to apply a higher bias voltage, so it has a larger power consumption. [Summary of the invention]

[0007] In view of the above problem, the present invention provides a microphone chip and a microphone including the microphone chip.

[0008] Specifically, the present invention proposes a microphone chip, which includes a substrate with a back cavity and a capacitor system arranged on the substrate, the capacitor system includes a back plate and a diaphragm arranged relatively spaced apart, and is characterized in that: the microphone chip also includes a piezoelectric piece attached to the diaphragm, and the piezoelectric piece generates an electrical signal as the diaphragm vibrates to control the power supply of the capacitor system.

[0009] Furthermore, the microphone chip also includes a control chip electrically connected to the piezoelectric plate and the capacitor system, and the control chip includes a trigger for receiving the electrical signal of the piezoelectric plate and a charge pump controlled by the trigger switch to supply energy to the capacitor system.

[0010] Furthermore, the backplate includes a backplate electrode layer, the diaphragm includes a diaphragm electrode layer, the backplate electrode layer and the diaphragm electrode layer are relatively spaced apart to form a flat plate capacitor, and the piezoelectric piece is attached and fixed to the diaphragm electrode layer.

[0011] Furthermore, the piezoelectric sheet includes a piezoelectric material layer attached to the diaphragm electrode layer and a piezoelectric electrode layer attached to a side of the piezoelectric material layer away from the diaphragm electrode layer.

[0012] Furthermore, the piezoelectric electrode layer and the back plate electrode layer are etched and separated from the same material layer.

[0013] Furthermore, the piezoelectric sheet is configured to have a shape that matches the diaphragm, and the piezoelectric sheet is completely fitted and fixed to the diaphragm.

[0014] Furthermore, the piezoelectric sheet is attached and fixed to the area of the diaphragm where the deformation is the largest during the vibration process.

[0015] Furthermore, the diaphragm includes a fixed portion fixed to the substrate and a vibrating portion connected to the fixed portion and suspended on the back cavity, and the orthographic projection of the piezoelectric piece along the vibration direction of the diaphragm is located on both the fixed portion and the vibrating portion.

[0016] Furthermore, the base includes four supporting columns, which are arranged in a matrix shape. The diaphragm includes four fixed parts fixed to the supporting columns and a vibrating part connected to the four fixed parts and suspended in the back cavity. The number of piezoelectric sheets is correspondingly set to four.

[0017] The present invention also provides a microphone, comprising the microphone chip as described in any one of the above items.

[0018] Beneficial effects of the present invention:

[0019] The microphone chip provided by the present invention has a piezoelectric plate on its diaphragm, which vibrates with the diaphragm to generate an electrical signal, which in turn controls the power supply to the microphone chip's capacitor system. This allows the microphone chip provided by the present invention to operate in standby mode with very low power consumption when no signal is input, thereby achieving the goal of reducing power consumption.

Brief Description of the Drawings

[0021] Figure 1 This is a partial structural diagram of the microphone chip provided by the present invention;

[0022] Figure 2 This is a partial structural exploded view of the microphone chip provided by the present invention;

[0023] Figure 3 is a schematic cross-sectional view of the microphone chip provided by the present invention;

[0024] Figure 4 It is a schematic diagram of the working process of the microphone chip provided by the present invention. [Specific implementation method]

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is described in detail below in conjunction with specific embodiments, so that the above-mentioned and other objects, features and advantages of the present invention will be clearer.

[0027] like Figures 1 to 3The figure shows the microphone chip 100 proposed by the present invention. In this embodiment, the microphone chip is prepared by MEMS technology, for example. When it is applied to acoustic devices, it is usually packaged in a MEMS microphone structure. The microphone chip 100 includes a substrate 1, which is made of silicon, glass or other suitable materials. A back cavity 2 is formed on the substrate 1. The back cavity 2 can be formed by a body etching process. The capacitor system 3 is arranged on the substrate 1. The capacitor system 3 includes a back plate 4 and a diaphragm 5 that are relatively spaced apart. The back plate 4 and the diaphragm 5 are respectively provided with a back plate electrode 41 and a diaphragm electrode 51. When the capacitor system 3 is energized, the back plate electrode 41 and the diaphragm electrode 51 are relatively arranged to form a flat plate capacitor. The back plate 4 is provided with a back plate hole 42 that passes through the back plate 4 and a convex column 43 that protrudes from the back plate 4 to the diaphragm 5. The back plate hole 42 is conducive to the transmission of the sound wave signal to the diaphragm 5 to cause vibration, which can reduce the noise signal of the microphone chip 100 and improve the sensitivity of the microphone chip 100. The base 1 includes four support columns 11 arranged in a matrix shape. The diaphragm 5 includes four fixing parts 52 fixed on the support columns 11 and a vibrating part 53 connected to the fixing parts 52 and suspended on the back cavity 2.

[0028] A piezoelectric sheet 7 is attached to the side of the diaphragm 5 close to the back plate 4. The piezoelectric sheet 7 includes a piezoelectric material layer 71 attached to the diaphragm electrode 51 and a piezoelectric electrode layer 72 attached to the side of the piezoelectric material layer 71 away from the diaphragm electrode 51. Furthermore, the piezoelectric electrode layer 72 and the back plate electrode 41 are etched and separated by the same material layer. Such an arrangement can simplify the preparation process of the microphone chip 100 and reduce the production cost of the microphone chip 100. The piezoelectric sheet 7 is attached to the side of the diaphragm electrode 51 close to the back plate 4. The piezoelectric sheet 7 includes a piezoelectric material layer 71 attached to the diaphragm electrode 51 and a piezoelectric electrode layer 72 attached and fixed to the side of the piezoelectric material layer 71 away from the diaphragm electrode 51. When an external sound wave signal is input, the diaphragm 5 vibrates and causes the piezoelectric material layer 71 to deform. According to the material properties of the piezoelectric material layer 71, the electrodes on the upper and lower sides (between the diaphragm electrode layer 51 and the piezoelectric electrode layer 72) generate a potential difference, thereby outputting an electrical signal to control the power supply for the capacitor system 3, exciting the capacitor system 3 to receive the sound wave signal.

[0029] like Figure 4As shown, when a sound wave signal is input, the diaphragm 5 vibrates, causing the piezoelectric material layer 71 of the piezoelectric plate 7 to deform. This in turn creates a potential difference between the piezoelectric electrode layer 72 of the piezoelectric plate 7 and the diaphragm electrode 51, thereby generating an electrical signal. The electrical signal is input to a control chip (not shown) electrically connected to the capacitor system 3 of the microphone chip 100. The control chip integrates a trigger (not shown) that receives the electrical signal. After receiving the electrical signal output by the piezoelectric plate 7, the trigger controls a switching charge pump (not shown) to energize the capacitor system 3. The capacitor system 3 then begins to receive the sound wave signal and outputs an electrical signal corresponding to the sound wave, which is then output through an amplifier.

[0030] The piezoelectric piece 7 is attached to the position where the deformation of the diaphragm 5 is the largest when the diaphragm 5 vibrates. Figures 2 to 3 As shown, the orthographic projection of the piezoelectric patch 7 along the vibration direction of the diaphragm 5 is located simultaneously on the fixed portion 52 and the vibrating portion 53 of the diaphragm 5. This arrangement allows the piezoelectric patch 7 to more sensitively sense the vibration deformation of the diaphragm 5, thereby generating an electrical signal to control the switching of the capacitor system 3. Furthermore, the piezoelectric patch 7 can also serve as structural reinforcement at the location where the deformation of the diaphragm 5 is the largest, effectively improving the structural stability of the microphone chip. The number of piezoelectric patches 7 is set to four, matching the support columns 11 of the substrate 1.

[0031] In other optional embodiments, the piezoelectric sheet 7 can also be set to the same shape as the diaphragm 5, and the piezoelectric sheet 7 is completely fitted and fixed to the diaphragm 5. Such a setting can make the piezoelectric sheet 7 and the diaphragm layer 5 be formed at the same time to reduce costs, and it is also beneficial to simplify the assembly process.

[0032] The microphone chip and microphone provided by the present invention can place the microphone chip's capacitor system in a low-power state when no signal is output, enabling standby at a lower power level and reducing the product's power consumption. Furthermore, the microphone chip and microphone provided by the present invention utilize a piezoelectric plate attached to the diaphragm to control the capacitor system's switching, which facilitates miniaturization of the microphone chip while maintaining low power consumption.

[0033] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A microphone chip comprising a substrate having a back cavity and a capacitor system disposed on the substrate, the capacitor system comprising a back plate and a diaphragm disposed relatively spaced apart, characterized in that: The microphone chip also includes a piezoelectric sheet attached to the diaphragm, and the piezoelectric sheet generates an electrical signal as the diaphragm vibrates to control the power supply of the capacitor system. The microphone chip also includes a control chip electrically connected to the piezoelectric sheet and the capacitor system, and the control chip includes a trigger for receiving the electrical signal from the piezoelectric sheet and a charge pump controlled by the trigger switch to supply power to the capacitor system.

2. The microphone chip according to claim 1, characterized in that The back plate includes a back plate electrode layer, the diaphragm includes a diaphragm electrode layer, the back plate electrode layer and the diaphragm electrode layer are relatively spaced apart to form a flat plate capacitor, and the piezoelectric sheet is attached and fixed to the diaphragm electrode layer.

3. The microphone chip according to claim 2, characterized in that The piezoelectric sheet includes a piezoelectric material layer attached to the diaphragm electrode layer and a piezoelectric electrode layer attached to a side of the piezoelectric material layer away from the diaphragm electrode layer.

4. The microphone chip according to claim 3, characterized in that The piezoelectric electrode layer and the back plate electrode layer are separated by etching from the same material layer.

5. The microphone chip according to claim 1, wherein: The piezoelectric sheet is configured to have a shape that matches the diaphragm, and the piezoelectric sheet is completely fitted and fixed to the diaphragm.

6. The microphone chip according to claim 1, characterized in that The piezoelectric piece is attached and fixed to the area of the diaphragm where the deformation is the largest during the vibration process.

7. The microphone chip according to claim 6, characterized in that The diaphragm includes a fixed portion fixed to the substrate and a vibrating portion connected to the fixed portion and suspended on the back cavity. The orthographic projection of the piezoelectric piece along the vibration direction of the diaphragm is located at both the fixed portion and the vibrating portion.

8. The microphone chip according to claim 7, characterized in that: The base includes four supporting columns, which are arranged in a matrix shape. The diaphragm includes four fixing parts fixed to the supporting columns and a vibrating part connected to the four fixing parts and suspended in the back cavity. The number of piezoelectric sheets is correspondingly set to four.

9. A microphone, characterized in that: Comprising the microphone chip according to any one of claims 1-8.

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