PATENT DOCUMENT

Publication Number: US-11937511-B2
Application Number: US-202318109180-A
Country: US
Kind Code: B2

Title: Multifunction magnetic and piezoresistive MEMS pressure sensor

Abstract:
Aspects of the subject disclosure include a pressure-sensing device consisting of a housing including a membrane and one or more piezoresistive elements disposed on the membrane to sense a displacement due to a deflection of the membrane. A first set of electrodes is disposed over the membrane, and a second set of electrodes is disposed on a permeable port of the device at a distance from the membrane. The first and second sets of electrodes form an electrostatic actuator to exert a repulsive force onto the membrane to reduce the deflection of the membrane.

Claims:
What is claimed is: 
     
       1. A pressure-sensing device, the device comprising:
 a housing including a membrane; 
 one or more piezoresistive elements disposed on the membrane and configured to sense a displacement due to a deflection of the membrane; 
 a first set of electrodes disposed over the membrane; and 
 a second set of electrodes disposed on a permeable port of the device at a distance from the membrane, 
 wherein the first set of electrodes and the second set of electrodes form an electrostatic actuator configured to exert a repulsive force onto the membrane to reduce the deflection of the membrane. 
 
     
     
       2. The device of  claim 1 , wherein the electrostatic actuator is further configured to measure an ambient pressure by sensing a change of capacitance between the first set and the second set of electrodes due to deflection of the membrane. 
     
     
       3. The device of  claim 2 , wherein the electrostatic actuator is further configured to extend a range of pressure measurement by reducing the deflection of the membrane and preventing deflection saturation of the membrane. 
     
     
       4. The device of  claim 2 , wherein the electrostatic actuator and the one or more piezoresistive elements are configured to enable detection of presence of contaminants by sensing a change in a damping parameter of the membrane due to a mass of a contaminant. 
     
     
       5. The device of  claim 4 , wherein the electrostatic actuator is configured to vibrate the membrane in response to an excitation at a set frequency. 
     
     
       6. The device of  claim 4 , wherein the one or more piezoresistive elements are configured to enable measurement of a damping of vibrations of the membrane. 
     
     
       7. The device of  claim 4 , wherein the contaminants include water and solid contaminants, and wherein the electrostatic actuator is configured to enable avoiding an inaccurate recording of exercise minutes or flights of stairs climbed due to pressure swings caused by evaporation of the water and capillary forces. 
     
     
       8. The device of  claim 1 , wherein the one or more piezoresistive elements and the electrostatic actuator are configured to individually enable use of the device as a microphone. 
     
     
       9. An apparatus comprising:
 a membrane including one or more piezoresistive elements configured to sense a displacement due to a deflection of the membrane; and 
 a first set of electrodes disposed over the membrane and a second set of electrodes disposed on a permeable port at a distance from the membrane to exert a repulsive force onto the membrane to reduce the deflection. 
 
     
     
       10. The apparatus of  claim 9 , wherein the first set of electrodes and the second set of electrodes form an electrostatic actuator configured to measure an ambient pressure. 
     
     
       11. The apparatus of  claim 10 , the electrostatic actuator is configured to vibrate the membrane in response to an excitation at a set frequency. 
     
     
       12. The apparatus of  claim 10 , wherein the one or more piezoresistive elements are configured to enable measurement of a damping of vibrations of the membrane. 
     
     
       13. The apparatus of  claim 10 , wherein the electrostatic actuator is configured to measure the ambient pressure by sensing a change of a capacitance between the first set and the second set of electrodes due to deflection of the membrane. 
     
     
       14. The apparatus of  claim 10 , wherein the electrostatic actuator and the one or more piezoresistive elements are configured to enable detection of presence of contaminants by sensing a change in a damping parameter of the membrane due to a mass of a contaminant. 
     
     
       15. The apparatus of  claim 14 , wherein the contaminants include water and solid contaminants, and wherein the electrostatic actuator is configured to enable avoiding an inaccurate recording of exercise minutes or flights of stairs climbed due to pressure swings caused by evaporation of the water and capillary forces. 
     
     
       16. The apparatus of  claim 14 , wherein the electrostatic actuator is further configured to extend a range of pressure measurement by reducing the deflection to prevent deflection saturation. 
     
     
       17. A communication device comprising:
 a pressure sensor component enclosed in a housing and including: 
 a membrane; 
 a permeable port at a distance from the membrane; 
 one or more piezoresistive elements disposed on the membrane and configured to sense a displacement due to a deflection of the membrane; 
 a first set of electrodes disposed over the membrane; and 
 a second set of electrodes disposed on the permeable port. 
 
     
     
       18. The communication device of  claim 17 , wherein the first set and second set of electrodes form an electrostatic actuator configured to:
 measure an ambient pressure by sensing a change of a capacitance between the first set of electrodes and the second set of electrodes due to the deflection; and 
 exert a repulsive force onto the membrane to reduce the deflection and extend a range of a pressure measurement by reducing the deflection and preventing a deflection saturation. 
 
     
     
       19. The communication device of  claim 18 , wherein the electrostatic actuator is further configured to vibrate the membrane in response to an excitation at a set frequency, and wherein the electrostatic actuator and the one or more piezoresistive elements are configured to enable detection of presence of contaminants by sensing a change in a damping parameter of the membrane due to a mass of a contaminant.

Description:
CROSS-REFERENCE TO PRIOR APPLICATIONS 
     This application is a divisional of the U.S. patent application Ser. No. 17/030,725 entitled “MULTIFUNCTION MAGNETIC AND PIEZORESISTIVE MEMS PRESSURE SENSOR,” filed Sep. 23, 2020, which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The present description relates generally to sensor technology, and more particularly, but not exclusively, to a multifunction magnetic and piezoresistive microelectromechanical sensor (MEMS) pressure sensor. 
     BACKGROUND 
     Portable electronic devices such as smartphones and smartwatches include pressure sensors for perceiving environmental pressure. The pressure sensor is sometimes used for barometric pressure measurements, which can be used to identify changes in elevation or depth in water. The changes in elevation are sometimes used to identify a location or exercise performed by a user of the device. For example, an activity monitor application running on the processing circuitry of the device worn or carried by a user while the user walks or runs up a flight of stairs or a hill may measure elevation changes. Portable electronic devices most commonly use capacitive or piezoresistive microelectromechanical system (MEMS) pressure sensors. 
     MEMS pressure sensors used in consumer electronic devices are operational within a defined pressure range (e.g., 30 kPa to 110 kPa), and underwater pressures can be as high as 3000 kPa (at about 300 m under water). MEMS pressure sensors typically rely on a diaphragm that deflects to detect a change in pressure. The performance of the sensor is dependent upon the sensor&#39;s linearity. The linearity of the sensor decreases as the diaphragm deflection increases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain features of the subject technology are set forth in the appended claims. However, for the purpose of explanation, several embodiments of the subject technology are set forth in the following figures. 
         FIGS.  1 A and  1 B  are schematic diagrams illustrating examples of a structure and an in-operation scheme of a multifunction magnetic and resistive microelectromechanical system (MEMS) sensor device, in accordance with various aspects of the subject technology. 
         FIG.  2    is a schematic diagram illustrating a contaminant-detection application of an example multifunction magnetic and resistive MEMS device, in accordance with various aspects of the subject technology. 
         FIG.  3    is a schematic diagram illustrating an example apparatus for temperature measurement using a multifunction magnetic and resistive MEMS device, in accordance with various aspects of the subject technology. 
         FIG.  4    is a schematic diagram illustrating an example structure of a planar magnetic coil of a multifunction magnetic and resistive MEMS device, in accordance with various aspects of the subject technology. 
         FIGS.  5 A,  5 B and  5 C  are schematic diagrams illustrating examples of a structure and in-operation schemes of a multifunction capacitive and resistive MEMS device, in accordance with various aspects of the subject technology. 
         FIG.  6    illustrates a wireless communication device in which aspects of the subject technology are implemented. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description, which includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be clear and apparent to those skilled in the art that the subject technology is not limited to the specific details set forth herein and may be practiced without these specific details. In some instances, well-known structures and components are shown in block-diagram form in order to avoid obscuring the concepts of the subject technology. 
     In some aspects, the subject disclosure provides a multifunction magnetic and resistive microelectromechanical system (MEMS) device. The disclosed MEMS device combines a magnetic out-of-plane actuator and a piezoresistive pressure sensor to provide an extended pressure-sensing range. The magnetic actuator can be activated by a flow of an electric current through magnetic coils to cause attraction and/or repulsion of the membrane via the Lorentzian force. The pressure sensing can be achieved through piezoresistive or magnetic measurement. 
     The extended range of pressure sensing of the MEMS device of the subject technology enables underwater pressure sensing for dive computer functions. The existing pressure sensors typically cover a pressure range of about 30 kpa to 160 kpa, which is usable for a limited underwater depth (e.g., about 10 feet). The magnetic coils can be activated to reduce membrane deflection to avoid bottoming out at high pressures. 
     Other important aspects of the disclosed MEMS device include water and contamination detection, a magnetic actuator driven at a set frequency, displacement measurement by the piezoresistor, and avoiding inaccurate recording of exercise minutes or flights of stairs climbed due to pressure swings caused by water evaporation and capillary forces. Furthermore, the MEMS device of the subject technology can be used as an integrated microphone or an ambient temperature sensor, as explained herein. The magnetic actuator displacement can be measured to record sound waves. When driven actively, the magnetic actuator can emit ultrasonic waves, of which the time-of-flight (ToF) across a device cavity is temperature-dependent and can be calibrated to measure ambient temperature. 
       FIGS.  1 A and  1 B  are schematic diagrams illustrating examples of a structure  100 A and an in-operation scheme  100 B of a multifunction magnetic and resistive MEMS device  100 , in accordance with various aspects of the subject technology. In one or more aspects, the multifunction magnetic and resistive MEMS device  100  (hereinafter, device  100 ) can be an environmental sensor, such as a pressure sensor, and can be integrated with a hand-held communication device such as a smartphone or a smartwatch. The structure  100 A of the device  100  includes a housing  102  enclosing a cavity  104 , a membrane  110 , planar magnetic coils  114 - 1  and  114 - 2  (hereinafter, coils  114 ) and piezoresistive elements  122 . The housing  102  can be made of materials including stainless steel, titanium or silicon and can have a width within a range of about 200-700 μm. The cavity  104  can be filled with air or an inert gas such as helium or other gases at a known pressure, for example, the atmospheric pressure or can be under vacuum. 
     The membrane  110  can be made of silicon with a thickness of a few micrometers (e.g., 3-10 μm). The coils  114 - 1  and  114 - 2  are attached to internal surface of the membrane  110  and a bottom surface of the housing  102 , respectively, as shown in  FIG.  1 A . The coils  114  form a magnetic actuator and can be actuated by applying a suitable electric current (e.g., a few mA) to the coils  114 . Applying current to the coils  114  can generate repulsion or attraction due to the Lorentz force. The piezoresistive elements  122  are attached to the membrane  110  and can provide variable resistances that vary with displacement caused by the bending of the membrane  110  due to the ambient pressure or deflection caused by the attractive magnetic force between the coils  114 . Ambient pressure can be measured through piezoresistive or magnetic measurement. In some aspects, the piezoresistive measurement can be performed by using a Wheatstone bridge circuit that converts a small change in resistance of the piezoresistive elements  122  to an output voltage or by using other methods. In one or more aspects, the magnetic measurement can be performed by applying a current to the coils  114  and measuring an output voltage due to a change of inductance caused by movement of the coils  114  or by using other methods. 
       FIG.  1 B  shows the in-operation scheme  100 B of the device  100 . In the in-operational scheme  100 B, the membrane  110  is deflected due to the applied pressure (e.g., the ambient pressure). The amount of deflection, as indicated by the arrow  116 , can be controlled by the Lorentz force of the coils  114 . The deflection of the membrane  110  depends upon the applied pressure to the membrane  110  and can saturate the membrane  110  such that it sticks to the bottom of the cavity  104  of  FIG.  1 A . In other words, without the use of the coils  114 , the device  100  has a limited range of operation that is restricted by the saturation of the membrane  110 . This limited range can be extended by applying a suitable current to the coils  114  to prevent the saturation of the membrane  110  by providing a counterforce (the Lorentz force), as shown in  FIG.  1 B . The Lorentz force balances out the force due to the applied pressure over the membrane  110  and can be used to calibrate the pressure-sensing aspect of the device  100 . 
       FIG.  2    is a schematic diagram illustrating a contaminant-detection application of an example multifunction magnetic and resistive MEMS device  200 , in accordance with various aspects of the subject technology. The multifunction magnetic and resistive MEMS device  200  (hereinafter, device  200 ) is similar to the device  100  of  FIG.  1 A  and, in the application shown in  FIG.  2   , is used to detect a contaminant  202  such as water over the membrane  110 , which cause an error in the pressure reading of typical pressure sensors. As the water evaporates the error disappears; however, it is hard to tell whether the change in reading was due to a change of height or the presence of water. The subject technology enables determining the presence of a contaminant  202  (e.g., water) on the membrane  110 . This allows the device  200  to avoid indicating false exercise minutes or number of flights of stairs climbed due to pressure swings caused by water evaporation. 
     The damping factor ξ of the membrane  110  is known to be proportional to an inverse of the square root of the mass m of the membrane, including the mass m of the contaminant  202  (e.g., water). The mass dependence of the damping factor ξ of the membrane  110  can be used to detect the presence of the contaminant  202  such as water. For this application the coils  114  are actuated using a signal at a set frequency and the change in damping is measured to determine the change of mass of the membrane  110  due to the presence of the contaminant  202  (e.g., water). The effect of the damping factor ξ on the membrane  110  can be measured by actuating the coils  114  to vibrate the membrane  110  and by using the piezoresistive elements to measure the displacement of the membrane  110 . If the displacement is different from the calibrated displacement using the same current with the same frequency to the coils  114 , it is inferred that a contaminant is present on the membrane. In some aspects, the presence of other contaminants such as dirt and particulate matter can be detected similarly. 
       FIG.  3    is a schematic diagram illustrating an example apparatus  300  for temperature measurement using a multifunction magnetic and resistive MEMS device, in accordance with various aspects of the subject technology. The apparatus  300  includes a housing  302 , a cavity  304 , a port  306  and a sensor  310 , which is a multifunction magnetic and resistive MEMS device such as the device  100  of  FIG.  1 A , described above. The sensor  310  is capable of generating ultrasonic waves  312  with the cavity  304 . The ultrasonic waves  312  can be generated by the vibrating membrane  110  of  FIG.  1 A  caused by the application of a current at a suitable frequency (e.g., KHz to low MHz) to the coils  114  of  FIG.  1 A . A ToF  320  for a two-way travelling of the ultrasonic waves  312  along the depth D of the cavity  304  can be measured by monitoring the resistance of the piezoresistive element to detect the reflected ultrasonic wave. The TOF  320  is the time difference between the emitted and reflected waves. Knowing the depth D and the ToF  320 , the speed v of the ultrasonic waves  312  can be determined. It is known that the speed v is proportional to the square root of the ambient temperature T. Therefore, the apparatus  300  allows for determining the ambient temperature T by measuring the ToF  320 , as explained above. 
       FIG.  4    is a schematic diagram illustrating an example structure of a planar magnetic coil  400  of a multifunction magnetic and resistive MEMS device, in accordance with various aspects of the subject technology. The planar magnetic coil  400 , as shown in  FIG.  4   , includes a number of loops  402  of an electrically conductive layer (trace) created on a substrate  404 . The loops  402 , for example, can be produced on the MEMS cavity by using photolithographic techniques. The loops  402  end in terminals  406  that can be used to apply an alternating current to the planar magnetic coil  400  to generate a magnetic field. The planar magnetic coil  400  can be used as the coils  114  of the device  100  of  FIG.  1   . 
       FIGS.  5 A,  5 B and  5 C  are schematic diagrams illustrating examples of a structure and in-operation schemes of a multifunction capacitive and resistive MEMS device  500 , in accordance with various aspects of the subject technology.  FIG.  5 A  shows the structure  500 A of the multifunction capacitive and resistive MEMS device  500  (hereinafter, device  500 ). In one or more aspects, device  500  can be an environmental sensor, such as a pressure sensor, and can be integrated with a hand-held communication device such as a smartphone or a smartwatch. The structure  500 A of the device  500  includes a housing  502  enclosing a first cavity  504 - 1  and a second cavity  504 - 2  separated by a membrane  510 , a lid  512 , electrodes  514  ( 514 - 1  and  514 - 2 ) and piezoresistive elements  522 . The lid  512  is air permeable and includes a number of air vents  532  and the electrodes  514 - 1  and  514 - 2  are attached, respectively, to an internal surface of the lid  512  and a surface of the membrane  510  facing the first cavity  504 - 1 . The electrodes  514  form an out-of-plane actuator (capacitor) and can be connected to a control voltage to control their separation. The pressure sensing can be achieved through piezoresistive measurement by the piezoresistive elements  522  or by the capacitive measurements using the electrodes  514 . 
       FIG.  5 B  shows a first in-operation scheme  500 B, in which the electrodes  514  create an electrostatic force  516  in response to the control voltage. The electrostatic force  516  can be an attractive force moving the membrane  510  toward the lid  512 , thus reducing deflection of the membrane  510  due to high pressure in order to prevent the membrane saturation. Alternatively, a capacitance between the electrodes  514  that is dependent on the separation of the electrodes  514  can be used to measure the deflection of the membrane  510 , which is an indication of the pressure exerted on the membrane  510 . 
       FIG.  5 C  shows a second in-operation scheme  500 C, in which the electrodes  514  create an electrostatic force  524  in response to the control voltage. The presence of water or other contaminants (e.g., oil or sweat) can be detected when the membrane  510  is actively driven by the electrostatic force of the electrodes  514 , for example, by measuring a damping factor ξ of the membrane  510 , as discussed above with respect to  FIG.  2   . 
     The device  500  of the subject technology can be used as an integrated microphone or an ambient temperature sensor, as explained above with respect to the sensor  310  of  FIG.  3   . Further, the capacitive actuator displacement can be measured to record sound waves. When driven actively, the capacitive actuator can emit ultrasonic waves, the ToF of which is temperature dependent across a device cavity and can be calibrated to measure ambient temperature, as described above with respect to the sensor  310  to  FIG.  3   . 
       FIG.  6    illustrates a wireless communication device  600  in which aspects of the subject technology are implemented. In one or more implementations, the wireless communication device  600  can be a smartphone or a smartwatch that hosts an apparatus of the subject technology, for example, for pressure, elevation and depth in water measurements. The wireless communication device  600  may comprise a radio-frequency (RF) antenna  610 , a duplexer  612 , a receiver  620 , a transmitter  630 , a baseband processing module  640 , a memory  650 , a processor  660 , a local oscillator generator (LOGEN)  670  and one or more transducers  680 . In various embodiments of the subject technology, one or more of the blocks represented in  FIG.  6    may be integrated on one or more semiconductor substrates. For example, the blocks  620 - 670  may be realized in a single chip or a single system on a chip, or may be realized in a multichip chipset. 
     The receiver  620  may comprise suitable logic circuitry and/or code that may be operable to receive and process signals from the RF antenna  610 . The receiver  620  may, for example, be operable to amplify and/or down-convert received wireless signals. In various embodiments of the subject technology, the receiver  620  may be operable to cancel noise in received signals and may be linear over a wide range of frequencies. In this manner, the receiver  620  may be suitable for receiving signals in accordance with a variety of wireless standards, Wi-Fi, WiMAX, Bluetooth, and various cellular standards. 
     The transmitter  630  may comprise suitable logic circuitry and/or code that may be operable to process and transmit signals from the RF antenna  610 . The transmitter  630  may, for example, be operable to up-convert baseband signals to RF signals and amplify RF signals. In various embodiments of the subject technology, the transmitter  630  may be operable to up-convert and amplify baseband signals processed in accordance with a variety of wireless standards. Examples of such standards may include Wi-Fi, WiMAX, Bluetooth, and various cellular standards. In various embodiments of the subject technology, the transmitter  630  may be operable to provide signals for further amplification by one or more power amplifiers. 
     The duplexer  612  may provide isolation in the transmit band to avoid saturation of the receiver  620  or damaging parts of the receiver  620 , and to relax one or more design requirements of the receiver  620 . Furthermore, the duplexer  612  may attenuate the noise in the receiver band. The duplexer  612  may be operable in multiple frequency bands of various wireless standards. 
     The baseband processing module  640  may comprise suitable logic, circuitry, interfaces, and/or code that may be operable to perform the processing of baseband signals. The baseband processing module  640  may, for example, analyze received signals and generate control and/or feedback signals for configuring various components of the wireless communication device  600 , such as the receiver  620 . The baseband processing module  640  may be operable to encode, decode, transcode, modulate, demodulate, encrypt, decrypt, scramble, descramble, and/or otherwise process data in accordance with one or more wireless standards. 
     The processor  660  may comprise suitable logic, circuitry, and/or code that may enable processing data and/or controlling operations of the wireless communication device  600 . In this regard, the processor  660  may be enabled to provide control signals to various other portions of the wireless communication device  600 . The processor  660  may also control transfer of data between various portions of the wireless communication device  600 . Additionally, the processor  660  may enable the implementation of an operating system or otherwise execute code to manage operations of the wireless communication device  600 . 
     The memory  650  may comprise suitable logic, circuitry, and/or code that may enable storage of various types of information such as received data, generated data, code, and/or configuration information. The memory  650  may comprise, for example, RAM, ROM, flash, and/or magnetic storage. In various embodiments of the subject technology, information stored in the memory  650  may be utilized for configuring the receiver  620  and/or the baseband processing module  640 . 
     The LOGEN  670  may comprise suitable logic, circuitry, interfaces, and/or code that may be operable to generate one or more oscillating signals of one or more frequencies. The LOGEN  670  may be operable to generate digital and/or analog signals. In this manner, the LOGEN  670  may be operable to generate one or more clock signals and/or sinusoidal signals. Characteristics of the oscillating signals such as the frequency and duty cycle may be determined based on one or more control signals from, for example, the processor  660  and/or the baseband processing module  640 . 
     In operation, the processor  660  may configure the various components of the wireless communication device  600  based on a wireless standard according to which it is desired to receive signals. Wireless signals may be received via the RF antenna  610 , amplified, and down-converted by the receiver  620 . The baseband processing module  640  may perform noise estimation and/or noise cancellation, decoding, and/or demodulation of the baseband signals. In this manner, information in the received signal may be recovered and utilized appropriately. For example, the information may be audio and/or video to be presented to a user of the wireless communication device  600 , data to be stored to the memory  650 , and/or information affecting and/or enabling operation of the wireless communication device  600 . The baseband processing module  640  may modulate, encode, and perform other processing on audio, video, and/or control signals to be transmitted by the transmitter  630  in accordance with various wireless standards. 
     The one or more transducers  680  may include miniature transducers such as the highly integrated MEMS pressure sensor of the subject technology (e.g.,  100 A of  FIG.  1 A or  500 A  of  FIG.  5 A ) that can detect the presence of water on the pressure sensor. The MEMS pressure sensor of the subject technology is a miniature device that can be readily integrated with the one or more transducers  680 . In one or more implementations, the processor  660  can process signals from the one or more transducers  680  to determine environmental parameters such as pressure as well as elevation and depth in water, and so on. 
     In accordance with various aspects of the subject disclosure, an apparatus includes a housing, one or more piezoresistive elements and a magnetic actuator. The housing includes a membrane, and the piezoresistive elements are disposed on the membrane in order to sense a displacement due to a deflection of the membrane. The magnetic actuator is disposed inside a cavity of the housing. The magnetic actuator exerts a repulsive force onto the membrane in order to reduce the deflection of the membrane. 
     In accordance with other aspects of the subject disclosure, a pressure sensing device includes a housing, including a membrane, one or more piezoresistive elements, a first set of electrodes and a second set of electrodes. The piezoresistive elements are disposed on the membrane and can sense a displacement due to a deflection of the membrane. The first set of electrodes are disposed over the membrane, and the second set of electrodes are placed on a permeable port of the device at a distance from the membrane. The first and second sets of electrodes form an electrostatic actuator in order to exert a repulsive force onto the membrane and to reduce the deflection of the membrane. 
     In accordance with other aspects of the subject disclosure, a wireless communication device consists of a first housing, including a port disposed on a wall of the device and a sensor disposed in the first housing. The sensor includes a second housing, including a membrane and one or more piezoresistive elements disposed on the membrane and configured to sense a displacement due to a deflection of the membrane. An actuator is disposed inside a cavity of the second housing. The actuator exerts a repulsive force onto the membrane to reduce the deflection of the membrane. 
     Various types of signal processing described above can be implemented in digital electronic circuitry or in computer software, firmware or hardware. The techniques can be implemented using one or more computer program products. Programmable processors and computers can be included in or packaged as mobile devices. The processes and logic flows can be performed by one or more programmable processors and by one or more programmable logic circuitry. General and special-purpose computing devices and storage devices can be interconnected through communication networks. 
     Some implementations include electronic components, such as microprocessors, storage and memory that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM), recordable compact discs (CD-R), rewritable compact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards), magnetic and/or solid-state hard drives, ultra-density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media can store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter. 
     While the above discussion primarily refers to microprocessor or multicore processors that execute software, some implementations are performed by one or more integrated circuits, such as application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some implementations, such integrated circuits execute instructions that are stored on the circuit itself. 
     As used in this specification and any claims of this application, the terms “computer”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For purposes of the specification, the terms “display” and “displaying” mean displaying on an electronic device. As used in this specification and any claims of this application, the terms “computer readable medium” and “computer readable media” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral signals. 
     Many of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer-readable storage medium (also referred to as a computer-readable medium). When these instructions are executed by one or more processing unit(s) (e.g., one or more processors, cores of processors, or other processing units), they cause the processing unit(s) to perform the actions indicated in the instructions. 
     In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage, which can be read into memory for processing by a processor. Also, in some implementations, multiple software aspects of the subject disclosure can be implemented as subparts of a larger program while remaining distinct software aspects of the subject disclosure. In some implementations, multiple software aspects can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software aspect described herein is within the scope of the subject disclosure. In some implementations, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs. 
     A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, subprograms, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. 
     It is understood that any specific order or hierarchy of blocks in the processes disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes may be rearranged, or that all illustrated blocks may be performed. Some of the blocks may be performed simultaneously. For example, in certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the subject disclosure. 
     The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. For example, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation, or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code. 
     A term such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A term such as “an aspect” may refer to one or more aspects and vice versa. A term such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A term such as “a configuration” may refer to one or more configurations and vice versa. 
     The word “example” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “example” is not necessarily to be construed as preferred or advantageous over other aspects or designs. 
     All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim.

Metadata:
Filing Date: 20230213
Publication Date: 20240319
Grant Date: 20240319
Priority Date: 20200923
Inventors: KHAN, MAJID
RIBEIRO, ROBERTO M.
GIDER, SAVAS
Assignee: APPLE INC
CPC Classifications: [{"code": "H10N30/88", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01L1/167", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L1/183", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L9/0055", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L19/0092", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S3/781", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/1071", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/2047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B2201/0264", "inventive": false, "first": false, "tree": "[]"}, {"code": "B81B2201/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01L9/0042", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10N30/88", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01L9/0055", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L19/0092", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B2201/0264", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01S3/781", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B2201/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10N30/2047", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L9/0055", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L1/183", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L19/0092", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01L1/167", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/101", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80740856