Acoustic sensor device with offset transducer

Abstract

A device includes a first sound port, a second sound port connected to the first sound port via an acoustic channel. The transducer is disposed in the acoustic channel such that a first channel portion of the acoustic channel couples a first side of the transducer to the ambient environment via the first sound port and a second channel portion of the acoustic channel couples a second side of the transducer to the ambient environment via the second sound port. A first acoustic channel length of a first channel portion of the acoustic channel between the first acoustic port and the transducer differs from a second acoustic channel length of a second channel portion of the acoustic channel between the second acoustic port and the transducer by an offset. And the offset is greater than the thickness of the transducer.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 529,242, filed on July 27, 2023, entitled “Offset Microphone,” the entire disclosure of which is hereby expressly incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to directional acoustic sensor devices. Background Technology

[0004] Directional acoustic sensor devices (e.g., directional microphones) typically include two sound ports that are coupled to the surrounding air when integrated into a module (e.g., a microphone module) or end-product device (e.g., a webcam or laptop computer). This integration often results in a long acoustic channel connecting the sound ports of the acoustic sensor device to the corresponding sound ports provided in the module or end product. Long acoustic channels often resonate within the audio frequency band. As the length of the acoustic channel increases, the resonant frequency undesirably decreases. This resonance often impairs the directivity of the integrated acoustic sensor device. Summary of the Invention

[0005] According to one aspect of this disclosure, an apparatus includes a first acoustic port, a second acoustic port connected to the first acoustic port via an acoustic channel, and a transducer deployed in the acoustic channel such that i) a first channel portion of the acoustic channel couples a first side of the transducer to the surrounding environment via the first acoustic port, and ii) a second channel portion of the acoustic channel couples a second side of the transducer to the surrounding environment via the second acoustic port. The first acoustic channel length of the first channel portion of the acoustic channel between the first acoustic port and the transducer differs from the second acoustic channel length of the second channel portion of the acoustic channel between the second acoustic port and the transducer by an offset. This offset is greater than the thickness of the transducer.

[0006] According to another aspect of this disclosure, a device includes a first acoustic port, a second acoustic port connected to the first acoustic port via an acoustic channel, and an acoustic sensor device including a transducer packaged and housed within the package. The transducer is deployed in the acoustic channel such that i) a first channel portion of the acoustic channel couples a first side of the transducer to the surrounding environment via the first acoustic port, and ii) a second channel portion of the acoustic channel couples a second side of the transducer to the surrounding environment via the second acoustic port. A first volume of the first channel portion of the acoustic channel between the first acoustic port and the transducer differs from a second volume of the second channel portion of the acoustic channel between the second acoustic port and the transducer by an offset volume. This offset volume is designed to reduce the effects of resonance in the acoustic channel to improve the directionality exhibited by the acoustic sensor device relative to sound waves traveling in the surrounding environment.

[0007] According to another aspect of this disclosure, an apparatus includes a first audio port, a second audio port connected to the first audio port via an acoustic channel, and a transducer disposed in the acoustic channel. The transducer is asymmetrically disposed within the acoustic channel with respect to the first and second audio ports at an offset greater than the thickness of the transducer.

[0008] In conjunction with any of the aspects mentioned above, the apparatus and / or methods described herein may alternatively or additionally include or relate to any combination of one or more of the following aspects or features: A transducer is housed in a package including a cover. The package is deployed in an acoustic channel such that the length of a first acoustic channel portion of the acoustic channel between a first acoustic port and the transducer differs from the length of a second acoustic channel portion of the acoustic channel between a second acoustic port and the transducer by the offset. The package is deployed in the acoustic channel such that i) the cover is oriented toward the first acoustic port, and ii) the offset positions the package such that the length of the first acoustic channel is less than the length of the second acoustic channel to place the transducer closer to the first acoustic port than the second acoustic port. The offset is greater than the thickness of the sealed space within the package defined by the cover adjacent to the transducer. The offset is greater than the thickness of the package. The offset is on the order of the package thickness. The offset is within an order of magnitude of the package thickness. The apparatus also includes a gasket. The acoustic channel is formed in the gasket. The acoustic channel is arranged in one of the following configurations: i) a V-shape, ii) a U-shape, or iii) a through-hole configuration. The characteristics of the cross-section of the first channel portion of the acoustic channel between the first sound port and the transducer differ from the characteristics of the cross-section of the second channel portion of the acoustic channel between the second sound port and the transducer. This characteristic is one or both of the diameter and shape of the cross-section. The offset is in the range of approximately 1 mm to 2.5 mm. The device also includes a housing in which the first and second sound ports are defined. The package includes a cover located on a side of the package closer to the first sound port than the second sound port. The offset volume places the transducer closer to the first sound port than the second sound port. The device also includes a housing in which the first and second sound ports are defined and a gasket disposed between the housing and the acoustic sensor device, wherein the acoustic channel is formed in the gasket. The device also includes a package in which the transducer is housed. The package includes a cover located on a side of the package closer to the first sound port than the second sound port, and the offset places the transducer closer to the first sound port than the second sound port. This offset is greater than the thickness of the sealed space within the package, defined by the cover adjacent to the transducer. Attached Figure Description

[0009] For a more complete understanding of this disclosure, reference should be made to the following detailed description and accompanying drawings, wherein similar reference numerals in the figures identify similar elements.

[0010] Figure 1 The diagram shows a cross-sectional view of an example device equipped with an acoustic sensor device 102, which is asymmetrically integrated into the device with an offset to avoid adverse resonance effects.

[0011] Figure 2 This is a graphical representation of the directivity index of an example device with an offset acoustic sensor.

[0012] Figure 3 A cross-sectional view of a device equipped with an acoustic sensor device according to an example is depicted, which has a distance-based offset to avoid adverse resonance effects.

[0013] Figure 4 A cross-sectional view of a device equipped with an acoustic sensor device according to an example is depicted, which has a volume-based offset to avoid adverse resonance effects.

[0014] Figure 5 This is a schematic cross-sectional view of an acoustic sensor device based on an example.

[0015] Embodiments of the disclosed device may take various forms. Specific embodiments are shown in the accompanying drawings and described below. It should be understood that this disclosure is intended to be illustrative. This disclosure is not intended to limit the invention to the specific embodiments described and shown herein. Detailed Implementation

[0016] A device is described that is equipped with a transducer (or an acoustic sensor device, such as a microphone, including the transducer) with an asymmetric deployment. In an example, an acoustic channel may be deployed between two acoustic ports of the device and may be provided to expose opposite sides of the transducer to the surrounding environment via the acoustic ports of the device. For example, the transducer may be deployed in the acoustic channel such that a first portion of the acoustic channel exposes a first side of the transducer to the surrounding environment via a first acoustic port and a second portion of the acoustic channel couples a second, opposite side of the transducer to the surrounding environment via a second acoustic port. Thus, the transducer can sense the pressure gradient between opposite sides of the transducer generated by sound waves traveling in the surrounding environment. The transducer may be asymmetrically deployed in the acoustic channel such that the first portion of the acoustic channel differs from the second portion of the acoustic channel. For example, as described in more detail below, in various examples, the first and second portions of the acoustic channel may differ by an offset in length and / or volume to provide asymmetry.

[0017] Accordingly, this asymmetry can constitute an offset and / or offset volume in the lengths of the two acoustic channels, and / or be characterized as an offset and / or offset volume in the lengths of the two acoustic channels or realized as an offset and / or offset volume in the lengths of the two acoustic channels. For example, the asymmetry can be an offset in the lengths of the two acoustic channels configured to couple a transducer to the surrounding environment. Alternatively or additionally, the asymmetry can be an offset volume between the volumes of the channels.

[0018] Asymmetrical deployment of transducers (or acoustic sensor devices including transducers, such as microphones) yields unexpected benefits. This asymmetry contradicts the notion that transducers, or acoustic sensor devices including transducers, should be perfectly positioned in the center of an acoustic channel (e.g., to maintain symmetry on each side). Off-center placement of the transducers (or acoustic sensor devices including transducers) reduces the effects of resonance (e.g., resonance within the acoustic channel). Consequently, the acoustic sensor devices achieve better directivity than expected. For example, an acoustic sensor device can achieve better directivity than one positioned within an acoustic channel without offset.

[0019] Asymmetrically deployed transducer or acoustic sensor devices (e.g., microphones) can be integrated into a wide variety of products (e.g., product devices) and / or combined with these products in other ways, which is useful. For example, asymmetry can be applied to various types of product devices with internal microphones coupled to long acoustic channels. Examples include webcams, laptops, conference phones, soundbars, and VR headsets.

[0020] Although generally described in conjunction with a microphone, the disclosed asymmetric acoustic channel configuration can be used in other applications and contexts. For example, the disclosed asymmetric acoustic channel configuration is useful in conjunction with accelerometers, gyroscopes, inertial sensors, pressure sensors, gas sensors, etc. The disclosed asymmetric acoustic channel configuration is described in a context of excitation by sound waves. However, in other contexts, alternative or additional stimuli can excite asymmetrically deployed transducers or sensor devices.

[0021] Figure 1 A device 100 equipped with an acoustic sensor device 102 is depicted according to one example. The acoustic sensor device 102 is asymmetrically integrated into the device 100 with an offset to avoid adverse resonance effects. For ease of illustration, only a portion of the device 100 is shown. The acoustic sensor device 102 may be, for example, a microphone. The device 100 may be or include any product device, such as a webcam. In another example, the device 100 may be a standalone module or a module that can be configured for integration into an end product device, such as a webcam. The acoustic sensor device 102 may be configured as a directional acoustic sensor device (e.g., a directional microphone) with two sound ports. Thus, the acoustic sensor device 102 may be configured to exhibit a directional response or pickup pattern (such as a dipole or figure-eight pattern) relative to sound waves traveling in the surrounding environment. In other examples, the acoustic sensor device 102 may be configured to exhibit a directional response or pickup pattern different from a dipole pattern, such as a cardioid pattern or other suitable directional pattern. Reference is made below. Figure 5An example acoustic sensor device that may correspond to acoustic sensor device 102 is described in more detail below. In other examples, acoustic sensor device 102 may be associated with... Figure 5 The acoustic sensor devices are different.

[0022] Device 100 includes a gasket 104 in which an acoustic channel 116 is defined. Device 100 also includes a device housing 106 in which a first acoustic port 120 and a second acoustic port 124 are defined. For example, the device housing 106 may include a wall, side, or other structure adjacent to the gasket 104. Thus, the gasket 104 is positioned between the device housing 106 and the acoustic sensor device 102. The acoustic channel 116 connects or couples the first acoustic port 120 to the second acoustic port 124. In this example, the gasket 104 defines a pair of tubes. These tubes are arranged to define a curved acoustic channel 116, which allows the first acoustic port 120 and the second acoustic port 124 to be positioned on the same surface of device 100. For example, the acoustic channel 116 may be a V-shaped or U-shaped channel.

[0023] Acoustic sensor device 102 includes a transducer 108 supported by a substrate such as a printed circuit board (PCB) 110 and protected by a cover 112. Acoustic sensor device 102 also includes, for ease of illustration, elements not shown in the original text. Figure 1 The application-specific integrated circuit (ASIC) shown is used to amplify the signal generated by transducer 108. The acoustic sensor device 102 also includes two audio ports. Figure 1 (Not shown in the diagram) includes a first acoustic port that can be embedded in a cover 112 and a second acoustic port that can be embedded in a PCB 110. The acoustic sensor device 102 may be supported by a substrate or product PCB 114. In some examples, the substrate or product PCB 114 is used to transmit signals from the acoustic sensor device 102 to other components in the device 100.

[0024] The acoustic channel 116 includes a first channel portion 118 and a second channel portion 122. The first channel portion 118 is a cover-side channel portion that couples a first acoustic port 120 in the device 100 to a first acoustic port embedded in the cover 112 of the acoustic sensor device 102. The second channel portion 122 is a PCB-side channel portion that couples a second acoustic port 124 in the device 100 to a second acoustic port embedded in the PCB 110 of the acoustic sensor device 102.

[0025] like Figure 1As shown, the acoustic sensor device 102 and transducer 108 are offset from the center point of the acoustic channel 116. The center point of the acoustic channel 116 can be defined as a location where the lengths and / or volumes of the first channel portion 118 and the second channel portion 122 in the acoustic channel 116 are equal. This offset can include an offset specifically designed to reduce the effect of resonance of the acoustic channel on the directivity exhibited by the acoustic sensor device relative to sound waves traveling in the surrounding environment. In the example, the offset is greater than an unintentional offset caused by, for example, manufacturing tolerances. In some examples, the acoustic sensor device 102 is offset such that the length of the first (cover-side) channel portion 118 is shorter than the length of the second (PCB-side) channel portion 122. In some cases, the acoustic sensor device 102 is offset by at least about 1 millimeter (mm) but less than 2.5 mm relative to the center point of the acoustic channel 116. In the example, the offset can be greater than the thickness 126 of the transducer 108. The thickness 126 of the transducer 108 may correspond to the thickness of the substrate (e.g., a silicone die substrate) in which the transducer 108 is formed. In some examples, the thickness 126 of the transducer 108 is less than 1 mm. In some examples, the thickness 126 of the transducer 108 is approximately 500 micrometers (µm). In some examples, the offset may be greater than the thickness of the diaphragm of the transducer 108 and less than the thickness of the substrate (e.g., a silicone die substrate) in which the transducer 108 is formed. For example, the transducer 108 may be a MEMS transducer formed in a silicone die with a thickness ranging from approximately 300 µm to 600 µm. The MEMS transducer may include a MEMS diaphragm with a thickness of, for example, less than 10 µm. The offset may be greater than the thickness of the MEMS diaphragm (e.g., greater than 10 µm) and less than the thickness of the silicone die in which the MEMS transducer is formed (e.g., less than 300 µm - 600 µm).

[0026] Alternatively or additionally, the offset may be greater than the thickness 128 of the acoustic sensor device 102 (e.g., greater than the thickness of the package of the acoustic sensor device), which may include the thickness of the cover 112 and the thickness of the PCB 110. In some examples, the thickness of the acoustic sensor device 102 may be in the range of 0.6 mm to 1.5 mm.

[0027] It can be assumed that the volume of air inside the package of acoustic sensor device 102 creates a type of asymmetry within the acoustic channel 116. Accordingly, shifting the position of acoustic sensor device 102 can counteract the adverse effects of the package of acoustic sensor device 102, thereby balancing both sides of the acoustic channel surrounding transducer 108.

[0028] The offset of the acoustic sensor device 102 relative to the center point of the acoustic channel 116 can be characterized by distance and / or volume. In terms of distance, the acoustic channel length of the first channel portion 118 of the acoustic channel 116 differs from the acoustic length of the second channel portion 122 of the acoustic channel 116 by an offset length. In terms of volume, the volume of the first channel portion 118 of the acoustic channel 116 differs from the volume of the second channel portion 122 of the acoustic channel 116 by an offset volume. In some examples, this offset volume may be similar to or larger than the space enclosed within the package of the acoustic sensor device.

[0029] The amount of offset can vary. For example, in some examples, the acoustic sensor device 102 is offset by at least approximately 1 mm relative to the center point. In other cases, the acoustic sensor device 102 is offset by at least approximately 2.5 mm relative to the center point of the acoustic channel 116. In the examples, the acoustic sensor device 102 is offset by an amount between 1 mm and 2.5 mm relative to the center point. Alternatively or additionally, the offset is greater than the thickness of the sealed space adjacent to the transducer 108 defined by the cover 112 of the acoustic sensor device 102.

[0030] In some cases, the offset is in the direction of the side of the acoustic sensor device 102 with the cover 112. Therefore, if the acoustic sensor device 102 is oriented such that the cover 112 is deployed closer to the first sound port (e.g., as...), Figure 1 If the acoustic sensor device 102 is located on one side of the first audio port 120 (as shown in the diagram), then the offset can be in the direction closer to the first audio port 120 than to the second audio port 124. Accordingly, in this case, in the embodiment, the length of the first channel portion 118 can be less than the length of the second channel portion 122.

[0031] In some examples, the offset is on the order of magnitude of the thickness 128 of the package of the acoustic sensor device 102. For example, the package of the acoustic sensor device 102 may have a thickness ranging from 0.6 mm to 1.5 mm, and the offset may be greater than the thickness of the package of the acoustic sensor device but less than approximately twice the thickness of the package of the acoustic sensor device. In another example, the offset may be on the order of magnitude of the thickness 128 of the package of the acoustic sensor device 102. For example, the package of the acoustic sensor device 102 may have a thickness of approximately 0.5 mm or 0.6 mm, and the offset may be greater than the thickness of the package of the acoustic sensor device but less than approximately 4 mm. By way of example only, the package of the acoustic sensor device 102 may have a thickness of approximately 0.5 mm or 0.6 mm, and the offset may be approximately 2 mm or 3 mm. The thickness 128 of the acoustic sensor device 102 may refer to the dimension of the package of the acoustic sensor device in the direction in which the sound wave travels through the acoustic channel 116.

[0032] In some examples, the offset is no greater than approximately 3 mm. In some examples, the offset is no greater than approximately six times the thickness 128 of the package of the acoustic sensor device 102. By way of example only, the package of the acoustic sensor device 102 may have a thickness of approximately 0.5 mm or 0.6 mm, and the offset may be approximately four, five, or six times the thickness of the package of the acoustic sensor device.

[0033] In some examples, the configuration of acoustic channel 116 can be varied in an alternative or additional manner. For example, the characteristics of the cross-section of acoustic channel 116 on one side of acoustic sensor device 102 can differ from the characteristics of the cross-section of acoustic channel 116 on the other side of acoustic sensor device 102. Thus, for example, the characteristics (e.g., size, diameter, shape, etc.) of the cross-section of the first portion 118 of acoustic channel 116 can differ from the characteristics (e.g., size, diameter, shape, etc.) of the cross-section of the second portion 122 of acoustic channel 116. Characteristics may include, for example, one or more of size, diameter, and shape.

[0034] Figure 2 Figure 200 is a graphical representation of the directivity index (DI) as a function of frequency for example acoustic sensor devices (e.g., microphones) deployed in V-shaped washer channels (such as acoustic channel 116 formed in washer 104) with and without offset. Figure 2 As shown, in the example shown, the average directivity index of the acoustic sensor device with or without offset ranges from 20 Hz to 20 kHz. The directivity is 4.6 dB. Curve 202 shows the directivity index of an acoustic sensor device centered within the acoustic channel, without any offset. As shown, the directivity index drops at approximately 10 kHz, indicating a loss of directivity. Generally, a value of 0 dB indicates an omnidirectional microphone, and a value of 4.8 dB is ideal for a dipole microphone. Curve 204 shows the directivity index of an acoustic sensor device offset by approximately 1 mm to 2 mm. The drop in directivity is mitigated, thus the acoustic sensor device maintains better directivity near 10 kHz.

[0035] Although the acoustic sensor device 100 is described in conjunction with a product device having sound ports located on the same surface of the final product (rather than, for example, on opposite sides), the location of the sound ports and / or other aspects of the configuration of the disclosed device may vary. Therefore, the shape and / or other aspects of the channel may vary accordingly. For example, the disclosed device is not limited to a configuration in which the acoustic sensor device is coupled to a V-shaped channel or other configurations using a bent tube to connect the sound ports of the acoustic sensor device to the same surface of the device in which the acoustic sensor device is integrated.

[0036] Figure 3 A cross-sectional view of a device 300 equipped with an acoustic sensor device 302, according to an example, is depicted. The acoustic sensor device 302 has a distance-based offset to avoid adverse resonance effects. Device 300 is similar to... Figure 1 Device 100 and includes with Figure 1 The components of device 100 are similarly numbered and will not be described in detail below for the sake of brevity. Acoustic sensor device 302 includes a transducer (e.g., a MEMS transducer) 308 mounted on or otherwise supported by a substrate (e.g., a PCB) 310. Acoustic sensor device 302 also includes a cover 312, which can be attached to substrate 310 and can encapsulate transducer 308. Substrate 310 and cover 312 can form a package for acoustic sensor device 302. Acoustic sensor device 302 also includes a first sound port that can be embedded in cover 312. Figure 3 (not shown in the image) and a second audio port that can be embedded in the substrate 310 ( Figure 3 (Not shown in the image).

[0037] Acoustic sensor device 302 is embedded within gasket 304. Unlike gasket 104, which is curved (e.g., arranged in a “V” or “U” shape), gasket 304 uses a through-hole configuration. Acoustic channel 316 is formed in gasket 304. Acoustic channel 316 includes a first channel portion 318 and a second channel portion 322. The first channel portion 318 of acoustic channel 316 is a cover-side channel portion that couples a first acoustic port 320 in device 300 to the top side of transducer 308 of acoustic sensor device 302 via a first acoustic port in cover 312 embedded in acoustic sensor device 302. The second channel portion 322 is a PCB-side channel portion that couples a second acoustic port 324 in device 300 to the bottom side of transducer 308 of acoustic sensor device 302. In various examples, the first channel portion 318 and the second channel portion 322 can be configured in the various ways described above with respect to the first channel portion 118 and the second channel portion 122 to provide an offset of the transducer 308 from the center of the acoustic channel 316. The acoustic sensor device 302 can be placed in the acoustic channel 316 such that the first channel portion 318 has an acoustic length different from that of the second channel portion 324. For example, as... Figure 3 As shown, the acoustic sensor device 302 can be placed in the acoustic channel 316 with an offset such that the length of the cover-side channel portion 318 is shorter than the length of the PCB-side channel portion 322.

[0038] Figure 4 A cross-sectional view of device 400 is depicted, which can be Figure 3 An alternative embodiment of device 300. Device 400 includes an acoustic sensor device 402 embedded within an acoustic channel 416 formed in a gasket 404. The acoustic channel 416 may be arranged to provide a volume-based offset to avoid adverse resonance effects. The acoustic sensor device 402 includes a transducer (e.g., a MEMS transducer) 408 mounted on or otherwise supported by a substrate (e.g., a PCB) 410. The acoustic sensor device 402 also includes a cover 412 that may be attached to the substrate 410 and may encapsulate the transducer 408. The substrate 410 and the cover 412 may form a package of the acoustic sensor device 402. The acoustic sensor device 402 also includes a first acoustic port that may be embedded in the cover 412. Figure 4 (not shown in the image) and a second audio port that can be embedded in the substrate 410 ( Figure 4 (Not shown in the image).

[0039] The acoustic channel 416 includes a first channel portion 418 and a second channel portion 422. The first channel portion 418 of the acoustic channel 416 is a cover-side channel portion that couples a first sound port 420 in the device 400 to the top side of the transducer 408 of the acoustic sensor device 402 via a first sound port in the cover 412 embedded in the acoustic sensor device 402. The second channel portion 422 is a PCB-side channel portion that couples a second sound port 424 in the device 400 to the bottom side of the transducer 408 of the acoustic sensor device 402. Figure 4 In the example shown, the length of the cover-side channel portion 418 is equal to the length of the PCB-side channel portion 422. However, relative to... Figure 3 The cover-side channel portion 418 is modified such that it has a smaller diameter relative to the PCB-side channel portion 422, and therefore a smaller air volume. This volume-based offset can counteract the asymmetry introduced by the packaging of the acoustic sensor device 402 and balance the two acoustic channels on opposite sides of the transducer 408.

[0040] Figure 5 This is a schematic cross-sectional view of an example acoustic sensor device 502. The acoustic sensor device 502 can be, for example, a microphone. In various examples, the acoustic sensor device 500 corresponds to the acoustic sensor device described above, such as the one referenced above. Figure 1 The acoustic sensor device 102 described above is referenced. Figure 3 The acoustic sensor device 302 described above and the reference above Figure 4 Acoustic sensor device 402 is described. Acoustic sensor device 502 includes elements with similar numbers, which may be the same as or similar to the corresponding elements of acoustic sensor devices 102, 302, and 402. However, in other examples, acoustic sensor devices 102, 302, and 402 may be different from acoustic sensor device 502.

[0041] Acoustic sensor device 502 includes a transducer 508. The transducer 508 may be, for example, a MEMS transducer. In other examples, the transducer 508 may include a suitable transducer other than a MEMS transducer. The transducer 508 may be attached to or otherwise supported by a PCB or other substrate 510 (collectively referred to herein as "PCB 510"). The PCB 510 may include one or more layers. In examples where the PCB 510 includes multiple layers, the respective layers in the multiple layers may be spaced apart from each other by a dielectric material. One or more layers of the PCB 510 may include conductive traces that can route electrical signals within the PCB 510. The acoustic sensor device 502 may also include a cover or other housing 512 (collectively referred to herein as "cover 512"). The cover 512 may be placed over the PCB 510 to enclose the components of the acoustic sensor device 502 mounted on or otherwise attached to the PCB 510. The cover 512 may be made of, or otherwise comprise, metal, plastic, ceramic, or other materials. Cover 512 and PCB 510 can form a package for acoustic sensor device 502. In other examples, the package for acoustic sensor device 502 can be formed in other suitable ways.

[0042] Transducer 508 may include a sensing element 530 positioned above cavity 542. Cavity 542 may be formed in transducer 508 by various microfabrication practices, including, for example, deep reactive ion etching (DRIE). Sensing element 530 may include, for example, a diaphragm. Sensing element 530 includes a first side facing outward relative to cavity 542 and a second side facing cavity 542. In one example, sensing element 530 may include a cantilever diaphragm structure attached to one end and free to move at the other end. In another example, sensing element 530 may include another suitable structure, such as a fixed-fixed structure fixed to more than two sides, such as a diaphragm fixed or anchored on all sides around the periphery.

[0043] The acoustic sensor device 502 may include a first acoustic port 536 formed in a cover 512 and a second acoustic port 538 formed in a PCB 510. A first air volume 560 may be formed in the package of the acoustic sensor device 502 between the PCB 510 and the cover 512 and may be configured to be exposed to the surrounding environment via the first acoustic port 536. A second air volume 562 may include a cavity 542 in the transducer 508 and may be configured to be exposed to the surrounding environment via the second acoustic port 538. Therefore, the sensing element 530 may have two opposite sides exposed to the surrounding environment and may sense the pressure gradient between the opposite sides of the sensing element 530 exposed to the surrounding environment. Because the sensing element 530 of the transducer 508 has two opposite sides exposed to the surrounding environment, and therefore the transducer 508 senses the pressure gradient between the opposite sides of the sensing element 530 exposed to the surrounding environment, the transducer 508 may exhibit a directional polarization pattern. For example, the transducer 508 may exhibit a dipole or figure-eight polarization pattern.

[0044] The acoustic sensor device 502 may also include an ASIC 574. The ASIC 574 may be mounted on or otherwise attached to the PCB 510. The ASIC 574 may be covered by a globtop 576. The ASIC 574 may be electrically coupled to the transducer 508. For example, the transducer 508 and the ASIC 574 may be electrically connected to each other via wire bonding 578 or directly, or via traces on the PCB 510. The ASIC 574 may also be electrically connected to the PCB 510 via wire bonding 580. In other examples, the transducer 508 and the ASIC 574 may be attached and / or electrically coupled using other suitable methods. For example, the transducer 508 may be attached to the PCB 510 using flip-chip technology. The ASIC 574 may be configured to read out and amplify the electrical signal generated by the transducer 508 based on the movement of the sensing element 530.

[0045] In various examples, as described herein, the acoustic sensor device 502 can be asymmetrically integrated into an acoustic channel. For example, the acoustic sensor device 502 can be integrated into an acoustic channel including a first portion coupled to a sound port 536 and a second portion coupled to a sound port 538. The first acoustic portion of the acoustic channel can be deployed between the sound port 536 and a first sound port of the module or end product device incorporating the acoustic sensor device 502. Thus, the first acoustic portion of the acoustic channel can expose an air volume 560 to the surrounding environment via the sound port 536 and the first sound port of the module or end product device incorporating the acoustic sensor device 502. The second portion of the acoustic channel can be deployed between the sound port 538 and a second sound port of the module or end product device incorporating the acoustic sensor device 502. Thus, the second acoustic portion of the acoustic channel can expose an air volume 562 to the surrounding environment via the sound port 538 and the second sound port of the module or end product device incorporating the acoustic sensor device 502. In various examples, the first portion and the second portion of the acoustic channel may be configured differently to provide the asymmetry as described herein and improve the directivity of the acoustic sensor device 502. For example, in various examples, the first portion and the second portion of the acoustic channel may differ by an offset in acoustic length and / or acoustic volume to provide the asymmetry as described herein and improve the directivity of the acoustic sensor device 502.

[0046] An example is described where an offset in the position of an acoustic sensor device (e.g., a microphone) within an acoustic channel results in higher directivity and mitigates the adverse effects of resonance. Furthermore, these unexpected benefits of the offset allow the acoustic sensor device to be used with longer acoustic channels. Therefore, the acoustic sensor device can be integrated and deployed with a wider range of products and product configurations.

[0047] The disclosed device offsets can be useful in terms of additions or substitutions in product design. For example, the offsets can lead to increased flexibility in product designs involving the placement of non-ideal acoustic sensor devices. The disclosed device offsets can be useful in counteracting the effects of such non-ideal acoustic sensor device placement.

[0048] The term “approximately” is used herein to include deviations from the specified value, and those skilled in the art will understand that the deviation is practically the same as the specified value, since there is no obvious, detectable or otherwise effective difference, for example, in operation, results, characteristics or other aspects of the disclosed methods and apparatus.

[0049] This disclosure has been described with reference to specific examples, which are intended to be illustrative only and not to limit the scope of this disclosure. Changes, additions, and / or deletions may be made to the examples without departing from the spirit and scope of this disclosure.

[0050] The foregoing description is provided for clarity only and should not be interpreted as containing unnecessary limitations.

Claims

1. An apparatus comprising: First audio port; A second audio port is connected to the first audio port via an acoustic channel; as well as A transducer, the transducer being deployed in the acoustic channel such that i) a first channel portion of the acoustic channel couples a first side of the transducer to the surrounding environment via a first sound port, and ii) a second channel portion of the acoustic channel couples a second side of the transducer to the surrounding environment via a second sound port; in: The length of the first acoustic channel of the first channel portion of the acoustic channel between the first sound port and the transducer differs from the length of the second acoustic channel of the second channel portion of the acoustic channel between the second sound port and the transducer by an offset amount. The offset is greater than the thickness of the transducer.

2. The device as claimed in claim 1, wherein: The transducer is housed in an encapsulation including a cover; and The encapsulation is deployed in the acoustic channel such that the length of the first acoustic channel of the first channel portion of the acoustic channel between the first sound port and the transducer differs from the length of the second acoustic channel of the second channel portion of the acoustic channel between the second sound port and the transducer by the offset.

3. The device of claim 2, wherein the package is deployed in the acoustic channel such that i) the cover is oriented toward the first sound port, and ii) the offset places the package such that the length of the first acoustic channel is less than the length of the second acoustic channel to place the transducer closer to the first sound port than the second sound port.

4. The device of claim 2, wherein the offset is greater than the thickness of the sealed space within the package defined by the cover adjacent to the transducer.

5. The device of claim 2, wherein the offset is greater than the thickness of the package.

6. The device of claim 2, wherein the offset is on the order of the thickness of the package.

7. The device of claim 2, wherein the offset is on the order of magnitude of the thickness of the package.

8. The device of claim 1, further comprising a gasket, wherein the acoustic channel is formed in the gasket.

9. The device of claim 1, wherein the acoustic channel is arranged as one of i) a V-shaped configuration, ii) a U-shaped configuration or iii) a through-hole configuration.

10. The device of claim 1, wherein the characteristics of the cross-section of the first channel portion of the acoustic channel between the first sound port and the transducer are different from the characteristics of the cross-section of the second channel portion of the acoustic channel between the second sound port and the transducer.

11. The device of claim 10, wherein the characteristic is one or both of the diameter of the cross section and the shape of the cross section.

12. The device of claim 1, wherein the offset is in the range of approximately 1 mm to 2.5 mm.

13. The device of claim 1, further comprising a device housing, wherein the first audio port and the second audio port are defined within the device housing.

14. An apparatus comprising: First audio port; A second audio port is connected to the first audio port via an acoustic channel; as well as An acoustic sensor device comprising a transducer packaged and housed within the package, the transducer being deployed in an acoustic channel such that i) a first channel portion of the acoustic channel couples a first side of the transducer to the surrounding environment via a first acoustic port, and ii) a second channel portion of the acoustic channel couples a second side of the transducer to the surrounding environment via a second acoustic port; in: The first volume of the first channel portion of the acoustic channel between the first sound port and the transducer differs from the second volume of the second channel portion of the acoustic channel between the second sound port and the transducer by an offset volume. The offset volume is designed to reduce the effects of resonance in the acoustic channel to improve the directivity of the acoustic sensor device relative to sound waves traveling in the surrounding environment.

15. The device of claim 14, wherein: The package includes a cover located on the side of the package closer to the first sound port than to the first sound port; and The offset volume places the transducer closer to the first sound port than the second sound port.

16. The apparatus of claim 14, further comprising: The device housing, wherein the first audio port and the second audio port are defined within the device housing; as well as A gasket is disposed between the device housing and the acoustic sensor device, wherein the acoustic channel is formed in the gasket.

17. The device of claim 14, wherein the acoustic channel is arranged as one of i) a V-shaped configuration, ii) a U-shaped configuration, or iii) a through-hole configuration.

18. The device of claim 14, wherein the characteristics of the cross-section of the first channel portion of the acoustic channel between the first sound port and the transducer are different from the characteristics of the cross-section of the second channel portion of the acoustic channel between the second sound port and the transducer.

19. An apparatus comprising: First audio port; A second audio port is connected to the first audio port via an acoustic channel; as well as A transducer, wherein the transducer is deployed in the acoustic channel; in: The transducer is asymmetrically deployed within the acoustic channel with an offset relative to the first and second audio ports, and The offset is greater than the thickness of the transducer.

20. The device of claim 19, further comprising an enclosure therein housing the transducer, wherein: The package includes a cover located on the side of the package closer to the first audio port than the second audio port; and The offset places the transducer closer to the first sound port than the second sound port.

21. The device of claim 19, further comprising an enclosure therein housing the transducer, wherein: The package includes a cap; and The offset is greater than the thickness of the sealed space within the package defined by the cover adjacent to the transducer.

22. The apparatus of claim 19, further comprising: The device housing, wherein the first audio port and the second audio port are defined within the device housing; as well as A gasket, wherein the gasket is disposed within the device housing, and wherein the acoustic channel is formed in the gasket.

23. The device of claim 19, further comprising a package therein housing the transducer, wherein the offset is greater than the thickness of the package.

24. The device of claim 23, wherein the offset is on the order of the thickness of the package.

25. The device of claim 23, wherein the offset is on the order of magnitude of the thickness of the package.

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