Acoustic transducer and microphone

Abstract

The invention provides an acoustic transducer and a microphone. By keeping the frequency characteristics, a vibrating electrode plate, to which high air pressured is applied, is prevented from displacement (deformation), and an electrostatic volumetric type acoustic transducer and the like are prevented from stress concentration or electrode plates are prevented from being damaged. A substrate (22) has a cavity (23) that penetrates up and down. A vibrating membrane (24) is arranged on the substrate (22) to cover the top opening of the cavity (23). A dome-shaped backboard (28) is arranged on the substrate (22) to cover the vibrating membrane (24). A fixed electrode plate (29), opposite to the vibrating membrane (24), is disposed below the backboard (28). The backboard (28) and the fixed electrode plate (29) are equipped with multiple acoustic holes (31). An opening (24a) is disposed in the center of the vibrating membrane (24), and an adjusting portion (25) is configured in the opening (24a). The adjusting portion (25) is supported by a supporting portion (44) that extends downwards under the backboard (28).

Description

technical field

[0001] The invention relates to an acoustic transducer and a microphone. Specifically, the present invention relates to a capacitance-type acoustic transducer configured using a capacitor structure composed of a vibrating electrode plate (vibrating membrane) and a fixed electrode plate. The invention also relates to a microphone using the acoustic transducer. Background technique

[0002] figure 1 (A) is a schematic diagram showing the structure of a conventional capacitance type acoustic sensor (acoustic transducer). In this acoustic sensor 11 , a cavity 13 is opened in a substrate 12 made of a silicon substrate or the like, and a vibrating membrane 14 (vibration electrode plate) is provided above the substrate 12 so as to cover the top opening of the cavity 13 . For example, in the case of a rectangular vibrating membrane 14 , its four corners are supported on the upper surface of the substrate 12 by the anchors 15 . A dome-shaped back plate 16 is forme...

Examples

Embodiment approach 1

[0073] Hereinafter, the acoustic sensor 21 which is the acoustic transducer according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 4 It is an exploded perspective view of the acoustic sensor 31 which is the acoustic transducer according to Embodiment 1 of the present invention. figure 2 (A) is a plan view showing the acoustic sensor according to Embodiment 1 of the present invention. figure 2 (B) means from figure 2 The acoustic sensor shown in (A) is a plan view of a state where the back plate 28 and the fixed electrode plate 29 are removed, and the vibrating membrane 24 is exposed. image 3 is a cross-sectional view of the acoustic sensor 21 .

[0074] The acoustic sensor 21 is an electrostatic capacitive element manufactured using MEMS technology. Such as image 3 As shown, in this acoustic sensor 21 , a vibrating membrane 24 (vibrating electrode plate) is provided on a constituent substrate 32 such as a silicon s...

Embodiment approach 2

[0102] Figure 7 (A) is a schematic sectional view showing the acoustic sensor 51 according to Embodiment 2 of the present invention. Figure 7 (B) is a plan view showing an enlarged central portion of the back plate 28 of the acoustic sensor 51 .

[0103] In the acoustic sensor 51 , the plurality of support portions 44 are extended downward from the central portion of the lower surface of the back plate 28 , and the adjustment portion 25 is supported by the plurality of support portions 44 . If the adjustment part 25 is supported by a plurality of supporting parts 44, the rigidity of the adjustment part 25 becomes high, and the adjustment part 25 is not easily deformed even by a large pressure. The distance of the edge of the adjustment part 25 becomes short.

[0104] (mention about modified example)

[0105] In each of the above-mentioned embodiments, the opening 24a and the adjusting portion 25 are circular, but the opening 24a and the adjusting portion 25 may also be ...

Embodiment approach 3

[0109] Figure 10 It is a cross-sectional view showing an acoustic sensor 61 according to Embodiment 3 of the present invention, which is characterized in that a vibrating membrane 24 is provided above a fixed electrode plate 29 . In the acoustic sensor 61 , a planar back plate 28 is provided on the upper surface of the substrate 22 via an insulating layer 62 . A fixed electrode plate 29 is formed on the upper surface of the back plate 28 . Above the cavity 23 , a plurality of sound holes 31 are opened on the back plate 28 and the fixed electrode plate 29 . In addition, the vibrating membrane 24 is disposed above the back plate 28 so as to face the fixed electrode plate 29 . Foot pieces 26 extending from diaphragm 24 are supported by anchors 27 provided on top of back plate 28 .

[0110] An opening 24 a is opened in the center of the vibrating membrane 24 , and the adjustment unit 25 is arranged in the opening 24 a. The adjustment part 25 is fixed to the upper end of the s...

technical field

[0001] The invention relates to an acoustic transducer and a microphone. Specifically, the present invention relates to a capacitance-type acoustic transducer configured using a capacitor structure composed of a vibrating electrode plate (vibrating membrane) and a fixed electrode plate. The invention also relates to a microphone using the acoustic transducer. Background technique

[0002] figure 1 (A) is a schematic diagram showing the structure of a conventional capacitance type acoustic sensor (acoustic transducer). In this acoustic sensor 11 , a cavity 13 is opened in a substrate 12 made of a silicon substrate or the like, and a vibrating membrane 14 (vibration electrode plate) is provided above the substrate 12 so as to cover the top opening of the cavity 13 . For example, in the case of a rectangular vibrating membrane 14 , its four corners are supported on the upper surface of the substrate 12 by the anchors 15 . A dome-shaped back plate 16 is forme...

Examples

Embodiment approach 1

[0073] Hereinafter, the acoustic sensor 21 which is the acoustic transducer according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 4 It is an exploded perspective view of the acoustic sensor 31 which is the acoustic transducer according to Embodiment 1 of the present invention. figure 2 (A) is a plan view showing the acoustic sensor according to Embodiment 1 of the present invention. figure 2 (B) means from figure 2 The acoustic sensor shown in (A) is a plan view of a state where the back plate 28 and the fixed electrode plate 29 are removed, and the vibrating membrane 24 is exposed. image 3 is a cross-sectional view of the acoustic sensor 21 .

[0074] The acoustic sensor 21 is an electrostatic capacitive element manufactured using MEMS technology. Such as image 3 As shown, in this acoustic sensor 21 , a vibrating membrane 24 (vibrating electrode plate) is provided on a constituent substrate 32 such as a silicon s...

Embodiment approach 2

[0102] Figure 7 (A) is a schematic sectional view showing the acoustic sensor 51 according to Embodiment 2 of the present invention. Figure 7 (B) is a plan view showing an enlarged central portion of the back plate 28 of the acoustic sensor 51 .

[0103] In the acoustic sensor 51 , the plurality of support portions 44 are extended downward from the central portion of the lower surface of the back plate 28 , and the adjustment portion 25 is supported by the plurality of support portions 44 . If the adjustment part 25 is supported by a plurality of supporting parts 44, the rigidity of the adjustment part 25 becomes high, and the adjustment part 25 is not easily deformed even by a large pressure. The distance of the edge of the adjustment part 25 becomes short.

[0104] (mention about modified example)

[0105] In each of the above-mentioned embodiments, the opening 24a and the adjusting portion 25 are circular, but the opening 24a and the adjusting portion 25 may also be ...

Embodiment approach 3

[0109] Figure 10 It is a cross-sectional view showing an acoustic sensor 61 according to Embodiment 3 of the present invention, which is characterized in that a vibrating membrane 24 is provided above a fixed electrode plate 29 . In the acoustic sensor 61 , a planar back plate 28 is provided on the upper surface of the substrate 22 via an insulating layer 62 . A fixed electrode plate 29 is formed on the upper surface of the back plate 28 . Above the cavity 23 , a plurality of sound holes 31 are opened on the back plate 28 and the fixed electrode plate 29 . In addition, the vibrating membrane 24 is disposed above the back plate 28 so as to face the fixed electrode plate 29 . Foot pieces 26 extending from diaphragm 24 are supported by anchors 27 provided on top of back plate 28 .

[0110] An opening 24 a is opened in the center of the vibrating membrane 24 , and the adjustment unit 25 is arranged in the opening 24 a. The adjustment part 25 is fixed to the upper end of the s...

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