System for generating broadband frequency output

Abstract

A microelectromechanical transducer assembly includes: a housing first portion defining an acoustic outlet port from an inner chamber to a surrounding environment, and having an active sound generating member positioned in the inner chamber operable to generate a first ultrasonic frequency; and a second housing portion defining a passive sound generating member acoustically coupled to the active sound generating member and operable to generate a second ultrasonic frequency that generates an audio band signal in combination with the first ultrasonic frequency.

Description

[0001] Cross Reference to Related Applications

[0002] This application is a non-provisional of co-pending U.S. Provisional Patent Application No. 63 / 674,671, filed July 23, 2024, and incorporated by reference herein. TECHNICAL FIELD

[0003] One aspect of the present disclosure relates to a microelectromechanical system (MEMS) speaker architecture with passive and active components that uses ultrasonic modulation and demodulation techniques to generate a wideband frequency output. Other aspects are also described and claimed. BACKGROUND

[0004] Portable communication or listening devices (e.g., smart phones, earphones, etc.) have one or more transducers located within them that convert input electrical audio signals into sound pressure wave outputs that can be heard by a user or convert sound pressure wave inputs into electrical audio signals. The transducers (e.g., speakers) can be used, for example, to output sound pressure waves corresponding to a far-end user’s voice, such as during a phone call, or to output sound pressure waves corresponding to sounds associated with a game a user wants to play or music a user wants to play. Because the profile of portable devices is relatively thin, the profile of the transducers is also relatively thin, which can make it difficult to maintain optimal sound quality. SUMMARY

[0005] One aspect of the present invention relates to a microelectromechanical system (MEMS) transducer or loudspeaker architecture for generating audible sound using ultrasonic modulation and demodulation techniques. For example, the loudspeaker may generate a broadband frequency output in the range of about 50 Hz to about 7 kHz. The ultrasonic modulation and demodulation loudspeaker technique uses amplitude-modulated ultrasonic waves along the amplitude of a desired audio signal to generate audible sound from modulated ultrasound. The modulated ultrasound is demodulated to produce the desired audible sound output. In some aspects, the MEMS transducer or loudspeaker disclosed herein may include chip-level unit cells, transducers, or actuators that may be arranged in an array to form a loudspeaker package or module. Sound can be generated from each unit cell and / or an array of unit cells using ultrasonic modulation. In some aspects, the array may include at least two or more unit cells, transducers, and / or actuators arranged side-by-side in the XY plane or arranged in a stacked or other configuration. Unlike other systems that use two active elements (e.g., a carrier beam for outputting an ultrasonic carrier frequency and a modulator beam for outputting a modulator frequency) to output a desired audible sound output, in the transducers or actuators disclosed herein, each unit cell, transducer, or actuator includes both an active element and a passive element that work together to form audible sound in air using the nonlinearity of ultrasound and air. Typically, the transducer or actuator may include passive elements (such as a resonator tuned to a specific frequency such that it behaves like a constant frequency generator) and a modulator beam (such as a diaphragm used to excite the resonator and generate a broadband frequency output). In some aspects, the resonator may be a Helmholtz resonator. The resonator and the air cavity surrounding the modulator beam may be tuned together to operate as a carrier frequency. The modulator beam is responsible for generating frequencies associated with the acoustic audio content that the transducer is intended to generate. The resonator receives its excitation energy from the output generated by the modulator. The property of this Helmholtz resonator is that it resonates at a specific frequency. The resonator will not oscillate off-frequency, as this is determined by its geometry. This allows the resonator to function like a carrier beam in a system with two active elements within a MEMS loudspeaker or transducer. Furthermore, in some aspects, a single modulator excites a single Helmholtz resonator to generate the audio output. In other aspects, multiple modulators can be present to excite a single Helmholtz resonator (shared across all modulators) to enhance or improve transducer efficiency. In yet another aspect, a low-pass or ultrasonic filter can be provided at the transducer unit outlet to increase loudspeaker efficiency.

[0006] In some aspects, this disclosure relates to a microelectromechanical transducer assembly comprising: a first housing portion defining an acoustic outlet port from an internal chamber to a surrounding environment and having an active sound generating member positioned within the internal chamber and operable to generate a first ultrasonic frequency; and a second housing portion defining a passive sound generating member acoustically coupled to the active sound generating member and operable to generate a second ultrasonic frequency, the second ultrasonic frequency being combined with the first ultrasonic frequency to generate an audio frequency band signal. In some aspects, the active sound generating member includes a diaphragm operable to deform to generate the first ultrasonic frequency. In other aspects, the diaphragm is positioned between the acoustic outlet port and the passive sound generating member. In yet another aspect, the passive sound generating member includes an acoustic chamber and a neck coupled to the first housing portion. In some aspects, the neck includes a width dimension and a length dimension greater than the width dimension. In other aspects, the passive sound generating member includes a Helmholtz resonator. In another aspect, the acoustic outlet port is a first acoustic outlet port, the inner cavity is a first inner cavity, the active sound generating member is a first active sound generating member, and the assembly also includes a second acoustic outlet port, a second inner cavity, and a second active sound generating member coupled to a second portion of the housing. In some aspects, the assembly also includes a filter coupled to the acoustic outlet port. The filter may include a tube having a first cross-sectional dimension and a second cross-sectional dimension different from the first cross-sectional dimension. In some aspects, the assembly is a first microelectromechanical transducer assembly, which is part of an array of other microelectromechanical transducer assemblies combined to generate a broadband frequency output.

[0007] In other aspects, the electronic device includes a housing coupled to a microelectromechanical transducer assembly comprising: a first portion defining an acoustic outlet port from an inner chamber to a surrounding environment and having an active sound generating member positioned within the inner chamber and operable to generate a first ultrasonic frequency; and a second portion defining a passive sound generating member acoustically coupled to the active sound generating member and operable to generate a second ultrasonic frequency, the second ultrasonic frequency being combined with the first ultrasonic frequency to generate an audio frequency band signal. In some aspects, the active sound generating member includes a diaphragm operable to deform to generate the first ultrasonic frequency. The diaphragm may be positioned between the acoustic outlet port and the passive sound generating member. In some aspects, the passive sound generating member may include an acoustic chamber and a neck coupled to the active sound generating member. In other aspects, the passive sound generating member may include a Helmholtz resonator. In some aspects, the first portion includes multiple acoustic outlet ports and multiple internal chambers containing multiple active sound generating components coupled to the passive sound generating component defined by the second portion. In other aspects, the passive sound generating component includes multiple acoustic paths coupled to the first portion at one end and to an acoustic chamber at the other end. In some aspects, a low-pass filter may be coupled to the acoustic outlet ports. In yet another aspect, the microelectromechanical transducer assembly is a first microelectromechanical transducer assembly that is part of an array of other microelectromechanical transducer assemblies combined to generate a broadband frequency output. In some aspects, the housing may be an earphone housing containing the microelectromechanical transducer assembly.

[0008] The above overview does not include an exhaustive list of all aspects of this disclosure. It is contemplated that this disclosure encompasses all systems and methods that can be implemented by all suitable combinations of the aspects outlined above and the various aspects disclosed in the detailed embodiments below and specifically pointed out in the claims filed with this patent application. Such combinations have specific advantages not specifically described in the above overview. Attached Figure Description

[0009] Several aspects are illustrated in the accompanying drawings by way of example rather than limitation, and similar reference numerals in the drawings indicate similar elements. It should be noted that references to “a” or “an” in this disclosure do not necessarily refer to the same aspect, and that they mean at least one.

[0010] Figure 1 An example is shown: a perspective cross-sectional view of one side of a transducer assembly.

[0011] Figure 2 ExamplesFigure 1 The transducer assembly is shown in a cross-sectional side view along line 2-2.

[0012] Figure 3 An example of a perspective cross-sectional view of another aspect of the transducer assembly is shown.

[0013] Figure 4 A cross-sectional side view of another aspect of the transducer assembly is shown.

[0014] Figure 5 Examples of what can be achieved therein are provided. Figures 1 to 4 A block diagram of one aspect of an electronic device for a transducer assembly. Detailed Implementation

[0015] In this section, we will explain several preferred aspects of this disclosure with reference to the accompanying drawings. Where the shape, relative position, and other aspects of the described components are not clearly defined, the scope of this disclosure is not limited to the components shown, which are for illustrative purposes only. Furthermore, while many details are set forth, it should be understood that some aspects of this disclosure can be implemented without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description.

[0016] The terminology used herein is for the purpose of describing particular aspects only and is not intended to limit this disclosure. Spatially related terms, such as “below,” “under,” “down,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. It should be understood that spatially related terms are intended to cover different orientations of the device in use or operation other than those shown in the accompanying drawings. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features may be oriented “above” other elements or features. Thus, the exemplary term “below” can cover both the orientations of above and below. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially related descriptors used herein are interpreted accordingly.

[0017] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context otherwise indicates. It should be further understood that the terms “comprising” and / or “including” define the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0018] The terms “or” and “and / or” as used herein should be interpreted as including or referring to any one or any combination thereof. Therefore, “A, B, or C” or “A, B, and / or C” means “any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or actions is inherently mutually exclusive in some way.

[0019] Figure 1 An example is shown: a perspective cross-sectional view of one side of a transducer assembly. Figure 2 Examples Figure 1The transducer assembly is shown in a cross-sectional side view along line 2-2. The transducer assembly 100 may include an array or other arrangement of multiple transducer units or cells 102. For example, assembly 100 may include an array of parallel microelectromechanical system (MEMS) transducer units or cells 102. Sound can be generated by the cells 102 using ultrasonic modulation. In some aspects, the transducer unit or cell 102 may be a MEMS electroacoustic transducer, such as a loudspeaker, that converts electrical signals into an audible output that can be output from a device in which the transducer assembly 100 is integrated. In other aspects, the transducer unit or cell 102 may convert sound into an electro-audio signal and may be referred to as a microphone. Each of the transducer units or cells 102 may be a separate unit that operates independently of each other to generate sound, but may be combined to form an array and their sound outputs are combined to produce an overall desired acoustic output (e.g., a broadband frequency output). As can be seen from an enlarged view of one of the units or cells 102, each unit or cell 102 may include a housing or enclosure 104. The housing or enclosure 104 may be a relatively rigid structure that supports and / or encloses some or all of the components of the unit or cell 102. In some aspects, the housing 104 may only support or enclose or otherwise connect to the transducer components (e.g., a transducer module). In other aspects, the housing or enclosure 104 may also form a device housing (e.g., an earphone housing) containing the transducer components and / or one or more transducer cells in the transducer unit 102, or may be part of such a device housing. In some cases, the housing 104 may include a plurality of walls or portions sealed together to form a first housing or enclosure portion 104A having a cavity or inner chamber 112 and a second housing or enclosure portion 104B having a cavity or inner chamber 114 for containing the transducer components. In some aspects, these wall portions may be considered fixed structures that may be attached together in a sealing manner along their interface surfaces by snap-fit, welding, adhesion, or some other mechanism or process to form the housing 104. The inner chambers 112 and 114 are open to each other, and the only opening from the inner chambers 112 and 114 within the housing 104 to the surrounding environment 124 may be an opening or port 110. In some aspects, the opening or port 110 may be considered an acoustic or sound output opening for outputting sound generated by the transducer components within the inner cavity of the transducer unit 102 (as indicated by the arrow) to the surrounding environment 124 (e.g., to a listener). The inner chambers 112 and 114 thus provide an acoustic pathway for the sound generated by the transducer components to the surrounding environment 124 through the opening 110, and may be considered as front volume chambers. In some aspects, the entire inner chamber may be considered as a front volume chamber, and a rear volume chamber or separate acoustic chamber behind the transducer components may be omitted.

[0020] Using ultrasonic modulation / demodulation technology, sound output through opening 110 can be generated by a moving, deformable, or active component 106 suspended within an inner cavity 112 defined by housing portion 104A and a passive component formed by housing portion 104B of housing 104. In some aspects, active component 106 may be, for example, a diaphragm suspended within or from housing portion 104A by a suspension member or other similar structure that allows the diaphragm to move or vibrate relative to housing portion 104A to generate a desired acoustic frequency. In some aspects, active component 106 may be a cantilever beam, plate, etc., that is attachable (or integrally formed therewith) to the inner surface of housing portion 104A at a fixed end and extends from that surface to a free end that is free to move, vibrate, or deflect to generate a desired acoustic frequency. In other aspects, the active component 106 may have arm-shaped fixed portions attached to the housing portion 104A at different locations around its periphery and a centrally movable, vibrating, or deflecting portion that moves with a piston-like motion to generate sound output. In some aspects, the active component 106 may be considered as a modulator beam that freely generates desired frequencies. Typically, the active component 106 is responsible for generating frequencies associated with the acoustic audio content that a loudspeaker or transducer is intended to generate. An offset gap is provided within the cavity 112 surrounding the active component 106 such that when the active component 106 is energized, the component 106 can achieve a desired offset amount (e.g., within the micrometer range) to generate sound using ultrasonic modulation / demodulation techniques without contacting the inner surface of the housing portion 104A. For example, the offset gap around all sides of the active component 106 may be equal to or less than the thickness of the active component 106 (e.g., four micrometers or less). In this respect, within the cavity 112 formed by the housing portion 104A surrounding the active member 106, the active member 106 occupies a significant portion of the air space within the cavity, and the gap between the member and the housing (e.g., the encapsulation) is relatively small. It is also understood that reducing the air space around the member 106 aims to further maintain the reduced size of the opening 110 necessary to bring the air into a nonlinear state. The air must be in a nonlinear state or region so that the component can operate to generate audible sound using the nonlinearity of ultrasound and air. Once the nonlinear state is achieved, the active member 106 and the passive member 108 work together to output lower and higher frequencies into the nonlinear air medium, thereby generating audible frequencies (or difference frequencies) that the component outputs to the surrounding environment. The generated sound can be output to the surrounding environment 124 through the opening 110.

[0021] As previously discussed, the active component 106 is responsible for generating frequencies associated with the acoustic audio content that the transducer unit 102 is intended to generate. Referring now to the passive component 108, the passive component 108 receives its excitation energy from the output generated by the active component. In this respect, the passive component 108 can be a resonator with a specific geometry such that it resonates at a specific frequency. The passive component 108 will not oscillate off-frequency, as this is determined by its geometry. This allows the passive component 108 to operate in a manner similar to a second active element in a MEMS loudspeaker that uses two active components (e.g., a carrier beam and a modulator beam) to generate sound output using ultrasonic frequencies. For example, in some aspects, the active component 106 can be understood to generate a first ultrasonic frequency (e.g., in the range of approximately 38 kHz plus a maximum of 20 kHz), and the passive component 108 to generate a second ultrasonic frequency (e.g., in the range of a maximum of 38 kHz). In some aspects, the passive component 108 may be a Helmholtz resonator having a neck portion 116 and a body portion 118 formed by a second housing portion 104B. The body portion 118 defines an inner chamber 114, which is connected to an inner chamber 112 via the neck portion 116. The neck portion 116 may have a specific length (L), width (W), and / or cross-sectional area, and the chamber 114 may have a specific volume selected to achieve a specific resonant frequency. The inner chamber or cavity 114 defined by the Helmholtz resonator, along with the remaining air volume within the chamber 112, work together to define a specific resonant frequency, wherein the length and cross-sectional area of ​​the neck portion 116 and the volume of the body portion 118 play a major role in defining the resonant frequency. In this respect, when the active component 106 is actively excited at a difference frequency, the active component also excites the defined resonant frequency of the passive component 108. This excitation generates two ultrasonic tones or frequencies in the transducer unit 102. In the presence of two ultrasonic tones or frequencies (one ultrasonic tone or frequency is generated by active means and the other ultrasonic tone or frequency is generated passively), the active and passive components can generate an audio band signal output that can be output by the transducer unit 102.

[0022] Figure 3 A perspective cross-sectional view of another aspect of the transducer assembly is illustrated. The transducer assembly 300 may include components related to the reference... Figures 1 to 2The described transducer assembly 100 is similar to an array or other arrangement of multiple transducer units or cells 302. Cells 302 can generate sound using ultrasonic modulation. In some aspects, the transducer unit or cell 302 can be a MEMS electroacoustic transducer (such as a loudspeaker) that converts electrical signals into an audible output that can be output from a device integrating the transducer assembly 300. In other aspects, the transducer unit or cell 302 can convert sound into an electro-audio signal and may be referred to as a microphone. The transducer unit or cell 302 may be related to reference... Figures 1 to 2 The transducer unit or unit 102 described is similar in that it includes a housing or enclosure 304 comprising a plurality of walls or portions sealed together to form a first housing or enclosure portion 304A and a second housing or enclosure portion 304B. In some aspects, these wall portions can be considered as fixed structures that can be attached together in a sealing manner along their interface surfaces by snap-fit, welding, adhesion, or some other mechanism or process to form the enclosure 304. However, in this configuration, the enclosure portion 304A defines a plurality of enclosure portions 304A-1, 304A-2, 304A-3, which define a plurality of inner chambers 312A, 312B, 312C and acoustic outlet ports 310A, 310B, 310C connecting the inner chambers 312A, 312B, 312C to the surrounding environment 324. In addition, multiple active components 306A, 306B, 306C (similar to the active components previously discussed) may be suspended or otherwise positioned within the inner chambers 312A, 312B, 312C and are operable to deform, vibrate, or otherwise move in order to generate frequencies associated with the acoustic audio content that the transducer is configured to generate, as previously discussed.

[0023] The inner chambers 312A, 312B, and 312C can be fully opened or connected to a single passive member 308 defined by the second housing portion 304B. The passive member 308 can be a Helmholtz resonator similar to those previously discussed; however, in this configuration, the passive member 308 may have multiple neck portions 316A, 316B, and 316C extending from a single body portion 318 formed by the second housing portion 304B. The body portion 318 may form a single acoustic chamber 314, which is connected to each of the housing portions 304A-1, 304A-2, and 304A-3 via the neck portions 316A, 316B, and 316C. The neck portions 316A, 316B, and 316C may have specific lengths (L), widths (W), and / or cross-sectional areas, and the chamber 314 may have a specific volume (V) selected to achieve a specific resonant frequency. The internal chamber or cavity 314 defined by the Helmholtz resonator, along with the remaining air volume within chamber 312, works together to define a specific resonant frequency. The length and cross-sectional area of ​​the neck portions 316A, 316B, and 316C, and the volume of the body portion 318, play a major role in defining the resonant frequency. In this respect, when the active component 306 is actively excited at a difference frequency, it also excites the defined resonant frequency of the passive component 308, enabling both the active and passive components to generate an audio frequency band signal output that can be output by the transducer 302. Using multiple active components 306A, 306B, and 306C to excite a single Helmholtz resonator (shared across all active components) can further improve or increase the transducer's efficiency.

[0024] Furthermore, it is envisioned that, in some aspects, the efficiency of the transducer can be increased by introducing a filter at the transducer outlet port, such as... Figure 4 exemplified. Representatively, Figure 4An example filter 402 is illustrated, which is coupled at one end from an inner cavity 112 formed by a housing portion 104A to an acoustic outlet port 110, and at the other end is open to the surrounding environment 124. For example, filter 402 can be attached to port 110 via any suitable attachment mechanism. Typically, filter 402 can be formed from a hollow passage or tube portion 404 having different cross-sectional dimensions along its length. Typically, tube portion 404 can have a first cross-sectional dimension or portion 406, a second cross-sectional dimension or portion 408, and a third cross-sectional dimension or portion 410. In some respects, the first cross-sectional dimension 406 and the third cross-sectional dimension 410 can be the same, while the second cross-sectional dimension 408 is different. For example, the cross-sectional dimension can be a width dimension, and the width (W1) of the first dimension or portion 406 and the third dimension or portion 410 can be narrower than the width (W2) of the second dimension or portion 408. These abrupt changes in the cross-sectional area of ​​tube 404 will cause different behaviors. In the narrow cross-sections 406 and 410, air moves without being compressed, so these locations behave like a mass (or like an inductor in an electroacoustic simulation), while in the larger cross-section 408, air can be compressed (like a capacitor in an electroacoustic simulation). Therefore, as... Figure 4 The presented inductor-capacitor-inductor topology can be considered to define a low-pass filter. However, the use of this filter can be understood to be different from its intended purpose. Typically, filter 402 provides an acoustic load on an active component (e.g., active component 106). With this acoustic load, the impedance mismatch between the active component and air is reduced, and once this occurs, radiation from the MEMS transducer becomes more efficient. Therefore, although filter 402 may be referred to herein as a low-pass filter, it is not used because of the associated low-pass characteristics, but because of its ability to improve the efficiency of the transducer or loudspeaker assembly to which it is attached (e.g., transducers 102, 302).

[0025] Now for reference Figure 5 , Figure 5 A block diagram illustrating some of the components of an electronic device in which one or more aspects may be implemented is shown. Device 500 can be any of several different types of consumer electronic devices. For example, device 500 can be any device equipped with a transducer, such as headphones (including in-ear headphones, on-ear headphones, and / or over-ear headphones), cellular phones, smartphones, media players, tablet-like portable computers, controllers, or any other device that can benefit from the transducer components disclosed herein.

[0026] In this respect, electronic device 500 includes a processor 512 that interacts with camera circuitry 506, motion sensor 504, storage device 508, memory 514, display 522, and user input interface 524. The main processor 512 also interacts with communication circuitry 502, main power supply 510, motion sensor 504, speaker 518, and microphone 520. Various components of electronic device 500 can be digitally interconnected and used or managed by a software stack being executed by processor 512. Many of the components shown or described herein can be implemented as one or more dedicated hardware units and / or a programmable processor (software executed by a processor such as processor 512).

[0027] Processor 512 controls the overall operation of device 500 by executing some or all of the operations of one or more application programs or operating system programs implemented on device 500, and by executing instructions (for software code and data) found on storage device 508. Processor 512 can drive display 522 and receive user input via user input interface 524 (e.g., a touchpad that can operate as a single touch-sensitive display panel). Furthermore, processor 512 can send audio signals to speaker 518 and / or motion sensor 504 to facilitate the operation of speaker 518 and / or actuator 504.

[0028] Storage device 508 uses non-volatile solid-state memory (e.g., flash memory) and / or dynamic non-volatile storage devices (e.g., spinning disk drives) to provide a relatively large amount of "persistent" data storage. Storage device 508 may include both local storage space and storage space on a remote server. Storage device 508 may store data as well as software components for controlling and managing different functions of device 500 at a higher level.

[0029] In addition to storage device 508, memory 514 may also be present, also referred to as main memory or program memory, which provides relatively fast access to stored code and data being executed by processor 512. Memory 514 may include solid-state random access memory (RAM), such as static RAM or dynamic RAM. One or more processors (e.g., processor 512) may be present, which run or execute various software programs, modules, or instruction sets (e.g., application programs) that have been transferred to memory 514 for execution while being permanently stored in storage device 508, thereby performing the various functions described above.

[0030] Device 500 may include communication circuitry 502. Communication circuitry 502 may include components for wired or wireless communication, such as two-way dialogue and data transmission. For example, communication circuitry 502 may include RF communication circuitry coupled to an antenna, enabling users of device 500 to make or receive calls via a wireless communication network. The RF communication circuitry may include an RF transceiver and a cellular baseband processor to enable calls via a cellular network. For example, communication circuitry 502 may include Wi-Fi communication circuitry, enabling users of device 500 to make or initiate calls using Voice over Internet Protocol (VoIP) connections and transmit data via a wireless local area network.

[0031] Device 500 may include microphone 520. Microphone 520 may be an acoustic transducer or sensor that converts sound in the air into electrical signals. Microphone circuitry may be electrically connected to processor 512 and power supply 510 to facilitate microphone operation (e.g., tilting).

[0032] Device 500 may include motion sensor 504, also known as an inertial sensor, which can be used to detect movement of device 500. Motion sensor 504 may include position, orientation, or motion (POM) sensors, such as accelerometers, gyroscopes, optical sensors, infrared (IR) sensors, proximity sensors, capacitive proximity sensors, acoustic sensors, sound wave or sonar sensors, radar sensors, image sensors, video sensors, global positioning (GPS) detectors, RF or acoustic Doppler detectors, compasses, magnetometers, or other similar sensors. For example, motion sensor 504 may be an optical sensor that detects movement or stillness of device 500 by detecting the intensity of ambient light or a sudden change in ambient light intensity. Motion sensor 504 generates a signal based on at least one of the position, orientation, and motion of device 500. This signal may include characteristics of motion, such as acceleration, velocity, direction, change of direction, duration, amplitude, frequency, or any other motion characteristic. Processor 512 receives the sensor signal and controls one or more operations of device 500 in part based on the sensor signal.

[0033] Device 500 also includes camera circuitry 506 that enables the digital camera functionality of device 500. One or more solid-state image sensors are built into device 500, and each solid-state image sensor may be located at the focal plane of an optical system including a corresponding lens. An optical image of the scene within the camera's field of view is formed on the image sensor, and the sensor responds by capturing the scene as a digital image or picture composed of pixels, which may then be stored in storage device 508. Camera circuitry 506 can also be used to capture video images of the scene. Device 500 also includes a main power supply 510, such as a built-in battery, as the main power source.

[0034] While certain aspects have been described and illustrated in the accompanying drawings, it should be understood that such aspects are merely illustrative and not limiting of the broad disclosure, and that this disclosure is not limited to the specific structures and arrangements shown and described, as various other modifications will be apparent to those skilled in the art. Therefore, the description should be considered exemplary rather than restrictive. Furthermore, to assist the Patent Office and any reader of any patent granted under this application in interpreting the appended claims, the applicant wishes to indicate that they do not intend to reference 35 U.SC112(f) in any appended claim or claim element unless “means for…” or “steps for…” is expressly used in a particular claim.

Claims

1. A microelectromechanical transducer assembly, the microelectromechanical transducer assembly comprising: The housing first portion defines an acoustic outlet port from the inner cavity to the surrounding environment and has an active sound generating member positioned in the inner cavity to generate a first ultrasonic frequency. and The second housing portion defines a passive sound generating member acoustically coupled to the active sound generating member and operable to generate a second ultrasonic frequency, which, in combination with the first ultrasonic frequency, generates an audio frequency band signal.

2. The microelectromechanical transducer assembly of claim 1, wherein the active sound generating member includes a diaphragm operable to deform to generate the first ultrasonic frequency.

3. The microelectromechanical transducer assembly of claim 2, wherein the diaphragm is positioned between the acoustic outlet port and the passive sound generating member.

4. The microelectromechanical transducer assembly of claim 1, wherein the passive sound generating component includes an acoustic chamber and a neck coupled to the first portion of the housing.

5. The microelectromechanical transducer assembly of claim 4, wherein the neck includes a width dimension and a length dimension greater than the width dimension.

6. The microelectromechanical transducer assembly of claim 1, wherein the passive sound generating component comprises a Helmholtz resonator.

7. The microelectromechanical transducer assembly according to claim 1, wherein the acoustic outlet port is a first acoustic outlet port, the inner chamber is a first inner chamber, the active sound generating component is a first active sound generating component, and the assembly further includes a second acoustic outlet port, a second inner chamber, and a second active sound generating component connected to the second part of the housing.

8. The microelectromechanical transducer assembly according to claim 1, wherein the microelectromechanical transducer assembly further comprises a filter connected to the acoustic output port.

9. The microelectromechanical transducer assembly of claim 8, wherein the filter comprises a tube having a first cross-sectional dimension and a second cross-sectional dimension different from the first cross-sectional dimension.

10. The microelectromechanical transducer assembly of claim 1, wherein the microelectromechanical transducer assembly is a first microelectromechanical transducer assembly, the first microelectromechanical transducer assembly being part of an array of other microelectromechanical transducer assemblies combined to generate a broadband frequency output.

11. An electronic device, the electronic device comprising: A housing coupled to a microelectromechanical transducer assembly, the microelectromechanical transducer assembly comprising: The first part defines an acoustic outlet port from the inner cavity to the surrounding environment and has an active sound generating component positioned within the inner cavity, operable to generate a first ultrasonic frequency; and The second part defines a passive sound generating component, which is acoustically coupled to the active sound generating component and operable to generate a second ultrasonic frequency, which is combined with the first ultrasonic frequency to generate an audio frequency band signal.

12. The electronic device of claim 11, wherein the active sound generating member includes a diaphragm operable to deform to generate the first ultrasonic frequency.

13. The electronic device of claim 12, wherein the diaphragm is positioned between the acoustic outlet port and the passive sound generating member.

14. The electronic device of claim 11, wherein the passive sound generating component includes an acoustic chamber and a neck connecting the acoustic chamber to the active sound generating component.

15. The electronic device of claim 11, wherein the passive sound generating component comprises a Helmholtz resonator.

16. The electronic device of claim 11, wherein the first portion defines a plurality of acoustic outlet ports and a plurality of internal chambers, the plurality of internal chambers including a plurality of active sound generating components coupled to the passive sound generating component defined by the second portion.

17. The electronic device of claim 16, wherein the passive sound generating component comprises a plurality of acoustic pathways connected at one end to the first portion and at the other end to an acoustic chamber.

18. The electronic device of claim 11, further comprising a low-pass filter coupled to the acoustic output port.

19. The electronic device of claim 18, wherein the microelectromechanical transducer assembly is a first microelectromechanical transducer assembly, the first microelectromechanical transducer assembly being part of an array of other microelectromechanical transducer assemblies combined to generate a broadband frequency output.

20. The electronic device of claim 11, wherein the housing is an earphone housing containing the microelectromechanical transducer assembly.

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