PATENT DOCUMENT

Publication Number: US-11595758-B2
Application Number: US-202117177178-A
Country: US
Kind Code: B2

Title: MEMS speaker

Abstract:
A MEMS speaker can include an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane, and thus provide a low-power, compact speaker with a large acoustically active area in a small volume. Neighboring folds in the corrugated MEMS structure may form pairs of MEMS electrodes that can be pushed together and/or pulled apart to deform the MEMS structure in a breathing motion that generates pressure differentials on opposing sides of the corrugated MEMS structure to generate sound.

Claims:
What is claimed is: 
     
       1. A speaker, comprising:
 a front volume; 
 a back volume; 
 a corrugated microelectromechanical systems (MEMS) structure disposed between the front volume and the back volume, wherein the corrugated MEMS structure comprises a single contiguous structure that extends, in a first dimension, from a first edge to a second edge, and includes a plurality of alternating folds disposed between the first edge and the second edge, wherein the corrugated MEMS structure comprises a plurality of MEMS electrodes, each forming a part of the single contiguous structure, the part extending in a second dimension perpendicular to the first dimension, between a corresponding pair of the plurality of alternating folds; 
 a first substrate disposed on a first side of the corrugated MEMS structure and having a first plurality of openings; and 
 a second substrate disposed on a second side of the corrugated MEMS structure and having a second plurality of openings that are misaligned with the first plurality of openings, 
 wherein the corrugated MEMS structure is disposed between the first substrate and the second substrate, and the first substrate and the second substrate are spaced apart along a third dimension perpendicular to the first dimension and the second dimension. 
 
     
     
       2. The speaker of  claim 1 , wherein first edge and second edge are fixed. 
     
     
       3. The speaker of  claim 2 , wherein the first edge and the second edge are each fixed to a corresponding resilient connector. 
     
     
       4. The speaker of  claim 1 , wherein the first edge and the second edge are floating edges. 
     
     
       5. The speaker of  claim 4 , further comprising at least one anchor beam that extends from one of the plurality of alternating folds to a support structure. 
     
     
       6. The speaker of  claim 1 , wherein the single contiguous structure extends, in a third dimension perpendicular to the first dimension and the second dimension, from a first end to second end, and wherein at least one of the first end or the second end is fixed. 
     
     
       7. The speaker of  claim 1 , wherein the single contiguous structure extends, in a third dimension perpendicular to the first dimension and the second dimension, from a first end to second end, and wherein at the first end and the second end are floating ends. 
     
     
       8. The speaker of  claim 1 , further comprising a plurality of additional corrugated MEMS structures disposed between the first substrate and the second substrate. 
     
     
       9. The speaker of  claim 8 , wherein the corrugated MEMS structure and the plurality of additional corrugated MEMS structures are misaligned with both the first plurality of openings and the second plurality of openings. 
     
     
       10. The speaker of  claim 9 , wherein the corrugated MEMS structure and the plurality of additional corrugated MEMS structures are spaced apart in a direction parallel to the second dimension. 
     
     
       11. The speaker of  claim 1 , wherein the plurality of alternating folds and the plurality of MEMS electrodes are evenly spaced apart along the first dimension when no voltage is applied to the corrugated MEMS structure. 
     
     
       12. The speaker of  claim 11 , wherein the plurality of alternating folds and the plurality of MEMS electrodes are unevenly spaced apart along the first dimension when no voltage is applied to the corrugated MEMS structure. 
     
     
       13. The speaker of  claim 12 , further comprising a plurality of posts extending, in a direction parallel to the second dimension, from at least one of a first substrate disposed on a first side of the corrugated mems structure or a second substrate disposed on a second side of the corrugated MEMS structure. 
     
     
       14. The speaker of  claim 13 , wherein each of the posts comprises a fixed electrode positioned adjacent at least a corresponding one of the plurality of MEMS electrodes. 
     
     
       15. The speaker of  claim 1 , wherein each of the alternating folds comprises a thinned fold. 
     
     
       16. The speaker of  claim 1 , wherein each of the alternating folds comprises a corrugated fold. 
     
     
       17. The speaker of  claim 1 , wherein each of the alternating folds comprises a tented fold. 
     
     
       18. The speaker of  claim 1 , further comprising:
 a third substrate disposed between the first substrate and the second substrate, wherein the corrugated MEMS structure is disposed between the first substrate and the third substrate; and an additional corrugated MEMS structure disposed between the third substrate and the second substrate. 
 
     
     
       19. A method of operating a speaker, the method comprising:
 applying a voltage to a corrugated microelectromechanical systems (MEMS) structure that is disposed between a front volume and a back volume; and 
 deforming, by the applied voltage, the corrugated MEMS structure to generate sound with the speaker, wherein the corrugated MEMS structure comprises a single contiguous structure that extends, in a first dimension, from a first edge to a second edge, and includes a plurality of alternating folds disposed between the first edge and the second edge, wherein the corrugated MEMS structure comprises a plurality of MEMS electrodes, each forming a part of the single contiguous structure, the part extending in a second dimension perpendicular to the first dimension between a corresponding pair of the plurality of alternating folds, wherein a first one of the plurality of MEMS electrodes has a first cross-sectional thickness, and wherein each of the corresponding pair of the plurality of alternating folds has a second cross-sectional thickness that is less than the first cross-sectional thickness. 
 
     
     
       20. The method of  claim 19 , wherein deforming the corrugated MEMS structure generates pressure differentials in the front volume and the back volume to generate the sound. 
     
     
       21. The method of  claim 20 , wherein deforming the corrugated MEMS structure to generate the pressure differentials causes air to move through openings in a substrate disposed adjacent to the corrugated MEMS structure to generate the sound. 
     
     
       22. The method of  claim 20 , wherein deforming the corrugated MEMS structure comprises causing pairs of the MEMS electrodes to move toward or away from each other along the first dimension. 
     
     
       23. The method of  claim 22 , wherein deforming the corrugated MEMS structure further comprises deforming the single contiguous structure in a direction that is parallel to the second dimension. 
     
     
       24. The method of  claim 20 , wherein deforming the corrugated MEMS structure comprises deforming the single contiguous structure in a direction that is parallel to the second dimension. 
     
     
       25. The method of  claim 24 , wherein the speaker comprises a first substrate disposed on a first side of the corrugated MEMS structure and a second substrate disposed on a second side of the corrugated MEMS structure, and wherein the direction that is parallel to the second dimension extends along a surface of the second substrate. 
     
     
       26. The method of  claim 19 , wherein deforming the corrugated MEMS structure comprises deforming the plurality of alternating folds, causing the plurality of MEMS electrodes to move toward or away from each other in a breathing motion. 
     
     
       27. The method of  claim 19 , wherein each of the alternating folds of the corrugated MEMS structure comprises an insulating element that electrically insulates adjacent ones of the plurality of MEMS electrodes from each other. 
     
     
       28. An electronic device, comprising:
 a speaker, comprising:
 a front volume; 
 a back volume; and 
 a corrugated microelectromechanical systems (MEMS) structure disposed between the front volume and the back volume, wherein the corrugated MEMS structure comprises a single contiguous structure that extends, in a first dimension, from a first moveably mounted edge to a second moveably mounted edge, and includes a plurality of alternating folds disposed between the first moveably mounted edge and the second moveably mounted edge. 
 
 
     
     
       29. The electronic device of  claim 28 , wherein the electronic device comprises a smart phone, a wearable device, or an earbud. 
     
     
       30. The electronic device of  claim 28 , wherein the first moveably mounted edge and the second moveably mounted edge are each fixed to a corresponding resilient connector. 
     
     
       31. The electronic device of  claim 28 , wherein the first moveably mounted edge and the second moveably mounted edge are floating edges. 
     
     
       32. The electronic device of  claim 28 , wherein the first moveably mounted edge and the second moveably mounted edge form a part of an acoustic seal between the front volume and the back volume.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to U.S. Provisional Patent Application No. 63/050,054, entitled “MEMS Speaker,” filed on Jul. 9, 2020, the disclosure of which is hereby incorporated herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present description relates generally to electronic devices, and more particularly, but not exclusively, microelectromechanical systems (MEMS) speakers. 
     BACKGROUND 
     Electronic devices such as computers, media players, cellular telephones, wearable devices, and headphones are often provided with speakers for generating sound output from the device. However, particularly as devices are implemented in ever smaller form factors, and as user demand for high quality audio increases, it can be challenging to provide speakers that generate high quality sound, particularly in compact devices such as portable electronic devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain features of the subject technology are set forth in the appended claims. However, for purpose of explanation, several embodiments of the subject technology are set forth in the following figures. 
         FIG.  1    illustrates a perspective view of an example electronic device having a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  2    illustrates a cross-sectional side view of a portion of an example electronic device having a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  3    illustrates a perspective view of another example electronic device having a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  4    illustrates a schematic cross-sectional side view of an example MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  5    illustrates a cross-sectional perspective view of a portion of an example MEMS structure of a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  6    illustrates a perspective view of an exemplary implementation of a portion of a MEMS speaker implemented with first and second substrates with openings in accordance with various aspects of the subject technology. 
         FIG.  7    illustrates a cross-sectional side view of a portion of an example MEMS speaker having multiple MEMS layers in accordance with various aspects of the subject technology. 
         FIG.  8    illustrates a cross-sectional side view of an example MEMS structure of a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  9    illustrates cross-sectional side views of an example MEMS structure of a MEMS speaker in various operational states in accordance with various aspects of the subject technology. 
         FIG.  10    illustrates a side view of an example MEMS structure of a MEMS speaker arranged for out-of-plane motion in accordance with various aspects of the subject technology. 
         FIG.  11    illustrates a cross-sectional side view of a portion of another example MEMS structure of a MEMS speaker in accordance with various aspects of the subject technology. 
         FIG.  12    illustrates a cross-sectional side view of a portion of another example MEMS structure of a MEMS speaker having thinned folds in accordance with various aspects of the subject technology. 
         FIG.  13    illustrates a cross-sectional side view of a portion of another example MEMS structure of a MEMS speaker having corrugated folds in accordance with various aspects of the subject technology. 
         FIG.  14    illustrates a cross-sectional side view of a portion of another example MEMS structure of a MEMS speaker having tented folds in accordance with various aspects of the subject technology. 
         FIG.  15    illustrates a cross-sectional side view of a portion of a MEMS speaker having a MEMS structure with a fixed, but compliant edge in accordance with various aspects of the subject technology. 
         FIG.  16    illustrates a cross-sectional side view of a portion of a MEMS speaker having a MEMS structure with a floating edge in accordance with various aspects of the subject technology. 
         FIG.  17    illustrates a cross-sectional side view of a portion of a MEMS speaker having a MEMS structure with a sliding edge in accordance with various aspects of the subject technology. 
         FIG.  18    illustrates a cross-sectional side view of a portion of a MEMS speaker having fixed electrodes in accordance with various aspects of the subject technology. 
         FIG.  19    illustrates a cross-sectional side view of a portion of a MEMS speaker having a MEMS structure with variable electrode spacing in accordance with various aspects of the subject technology. 
         FIG.  20    illustrates top view of a portion of a MEMS speaker having variable electrode spacing in accordance with various aspects of the subject technology. 
         FIG.  21    illustrates a flow diagram of an example process for operating a MEMS speaker in accordance with one or more implementations. 
         FIG.  22    illustrates an electronic system with which one or more implementations of the subject technology may be 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. The detailed description 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. 
     Portable electronic devices such as a mobile phones, portable music players, smart watches, tablet computers, laptop computers, other wearable devices, headphones, earbuds, and the like often include a speaker for generating sound. 
     In accordance with various aspects of the subject disclosure, a low-power, compact speaker is provided that includes an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane. The speaker, which is referred to herein variously as a MEMS speaker or a micro-speaker, is implemented with corrugations in the MEMS structure that provide a large acoustically active area in a small volume. Neighboring corrugations in the corrugated MEMS structure may form pairs of MEMS electrodes that can be pushed together and/or pulled apart (e.g., in a breathing motion that generates pressure differentials above and below the corrugated MEMS structure) to generate sound. The speaker can include multiple corrugated MEMS structures that are operated in pairs. One or more corrugated MEMS structures can be mounted between a front volume and a back volume of the speaker. In one or more implementations, one or more corrugated MEMS structures can be mounted between top and bottom substrates with openings to allow airflow to and from the corrugated MEMS structure. In one or more implementations, multiple layers of corrugated MEMS structures can be stacked. 
     In one or more implementations, wide and/or varied spacing between the MEMS electrodes can be provided to tune the corrugated MEMS structure to low and/or varied frequencies. In these implementations, posts on the top and/or bottom substrates can extend toward the corrugated MEMS structure to provide fixed (e.g., additional) electrodes for controlling the motion of the MEMS electrodes. 
     An illustrative electronic device including a speaker is shown in  FIG.  1   . In the example of  FIG.  1   , device  100  (e.g., an electronic device) has been implemented using a housing that is sufficiently small to be portable and carried by a user (e.g., device  100  of  FIG.  1    may be a handheld electronic device such as a tablet computer or a cellular telephone or smart phone). As shown in  FIG.  1   , device  100  includes a display such as display  110  mounted on the front of housing  106 . Device  100  includes one or more input/output devices such as a touch screen incorporated into display  110 , a button or switch such as button  104  and/or other input output components disposed on or behind display  110  or on or behind other portions of housing  106 . Display  110  and/or housing  106  include one or more openings to accommodate button  104 , a speaker, a light source, or a camera. 
     In the example of  FIG.  1   , housing  106  includes two openings  108  on a bottom sidewall of housing. One or more of openings  108  forms a port for an audio component. For example, one of openings  108  may form a speaker port for a speaker disposed within housing  106  and another one of openings  108  may form a microphone port for a microphone disposed within housing  106 . Openings  108  may be open ports or may be completely or partially covered with a permeable membrane or a mesh structure that allows air and sound to pass through the openings. Although two openings  108  are shown in  FIG.  1   , this is merely illustrative. One opening  108 , two openings  108 , or more than two openings  108  may be provided on the bottom sidewall (as shown) on another sidewall (e.g., a top, left, or right sidewall), on a rear surface of housing  106  and/or a front surface of housing  106  or display  110 . In some implementations, one or more groups of openings  108  in housing  106  may be aligned with a single port of an audio component within housing  106 . Housing  106 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. 
     The configuration of device  100  of  FIG.  1    is merely illustrative. In other implementations, device  100  may be a computer such as a computer that is integrated into a display such as a computer monitor, a laptop computer, a smaller portable device such as a smart watch, a pendant device, or other wearable or miniature device, a media player, a gaming device, a navigation device, a computer monitor, a television, a headphone, an earbud, or other electronic equipment. In some implementations, device  100  may be provided in the form of a computer integrated into a computer monitor. Display  110  may be mounted on a front surface of housing  106  and a stand may be provided to support housing (e.g., on a desktop). 
     In some implementations, device  100  may be provided in the form of a wearable device such as a smart watch. In one or more implementations, housing  106  may include one or more interfaces for mechanically coupling housing  106  to a strap or other structure for securing housing  106  to a wearer. It should be appreciated that, although device  100  includes one opening in the example of  FIG.  1   , device  100  may include one, two, three, four, or more than four openings. Device  100  may include one, two, three, or more than three audio components each mounted adjacent to one or more of openings  108 . 
     A speaker disposed within housing  106  transmits sound through at least one associated opening  108 . A microphone may also be provided within housing  106  that receives sound through at least one associated opening in the housing. In one or more implementations, the speaker may be implemented as a microelectromechanical systems (MEMS) speaker. 
       FIG.  2    illustrates a cross-sectional view of a portion of device  100  in which an audio component is mounted. In the example of  FIG.  2   , device  100  includes speaker  200 . Speaker  200  includes speaker housing  202  mounted adjacent at least one opening  108  in housing  106 . Speaker housing  202  may be formed form one or more materials such as plastic or metal. As shown, speaker  200  may include a MEMS component  204  disposed within the speaker housing  202 . As shown in  FIG.  2   , the MEMS component  204  may be mounted between a back volume  217  and a front volume  219  (e.g., as defined by the speaker housing  202  and/or one or more portions of the device housing  106 ). As illustrated in  FIG.  2   , speaker housing  202  may include an opening that is aligned with opening  108  in housing  106  so that sound generated by MEMS component  204  (e.g., responsive to control signals received from device circuitry  206 ) can be transmitted through the opening  108  to the external environment. Opening  108  may be an open port or may include a cover  210  such as a membrane or a mesh structure that discourages entry of liquid into speaker housing  202 , but that is permeable to sound and air. 
     MEMS component  204  may be coupled to device circuitry such as device circuitry  206  (e.g., one or more processors of the device) via a connector  208 . Connector  208  may include a flexible integrated circuit or another flexible or rigid conductive connector. In one or more implementations, connector  208  may electrically couple to one or more contacts on speaker housing  202  that are electrically coupled (e.g., via wire bonds or other conductive connections) to MEMS component  204 . However, it should be appreciated that, in one or more implementations, MEMS component  204  may be provided without a separate speaker housing  202  (e.g., and coupled directly to connector  208  and/or device circuitry  206 ). In implementations in which MEMS component  204  is provided without a separate speaker housing, an outer layer of the MEMS component  204  can be attached to an inner surface of housing  106  (e.g., by adhesive  212  or another coupling mechanism), mounted to a printed circuit within device  100 , or otherwise mounted within housing  106  so as to project sound out of housing  106  through opening  108 . 
       FIG.  3    illustrates another example electronic that may include a MEMS speaker. In the example of  FIG.  3   , a device  300  is implemented as an earbud having a MEMS speaker formed by a MEMS component  204 . As shown, device  300  may include a housing  302  having a shape that is configured to fill the opening of an ear canal of a user wearing the earbud. Device  300  may include one or more openings, such as an opening  304  in the housing  302 . Housing  302  may have a size and a shape that conforms to a portion of an outer ear, such that opening  304  may be aligned with the ear canal of the user when the earbud is worn by the user, to allow sound generated by MEMS component  204  to enter the user&#39;s ear canal. Device  300  may be a wired or wireless earbud that communicates with a companion device such as device  100  of  FIG.  1    to receive instructions and/or signals to operate the MEMS speaker corresponding to MEMS component  204  to generate sound. The housing  302  of device  300 , and/or a speaker housing within the housing  302  can form (e.g., define) a back volume and a front volume for the MEMS component  204 . 
     The electronic devices of  FIGS.  1  and  3    are merely illustrative, and it should be appreciated that a MEMS speaker as described herein can be implemented in any suitable electronic device for which it is desired to generate high quality sound from within a small volume. 
       FIG.  4    shows an example of a portion of a speaker for an electronic device, in an implementation in which a MEMS actuator (or transducer) is implemented as a MEMS speaker. In the example of  FIG.  4   , speaker  200  includes a MEMS structure  410  that form a MEMS layer  408  between back volume  217  and front volume  219 .  FIG.  4    illustrates an arrangement in which the MEMS structure  410  is disposed in a plane defined by x and y directions, with the front and back volumes disposed on opposing sides of the MEMS structure  410  in a z direction. However, this arrangement is merely illustrative and other arrangements are contemplated and described herein. As described in further detail herein, speaker  200  may be operated by applying a voltage to a MEMS structure  410 , such as a corrugated microelectromechanical systems (MEMS), that is disposed between the front volume  219  and the back volume  217 , where applying the voltage causes deforming, by the applied voltage, of the corrugated MEMS structure to generate sound with the speaker. The sound that is generated may pass through an opening  411  in a speaker housing and/or through one or more openings in a device housing to provide sound for an electronic device, such as for one of the electronic devices  100  and  300  of  FIGS.  1  and  3   . 
       FIG.  5    illustrates a perspective view of a MEMS structure  410  in accordance with one or more implementations. In the example of  FIG.  5   , MEMS structure  410  is formed from a single contiguous structure  501  that extends, in a first dimension (e.g., the A dimension in  FIG.  5   ), from a first edge  502  to a second edge  504 , and includes multiple alternating folds  500  disposed between the first edge  502  and the second edge  504 . The single contiguous structure  501  may be formed using MEMS manufacturing methods (e.g., deposition, etching, lithography, patterning, dicing, etc., which allows the MEMS components  204  to be mass manufacturable) to form a corrugated MEMS structure defined by the alternating folds  500  as shown. As shown, MEMS structure  410  has deep corrugated structures placed in close proximity with good tolerance. The micro-scale of MEMS structure  410  enables dense packing of the corrugations (which can provide advantages in terms of large surface area of the actuator per total die area). As shown, the single contiguous structure  501  may include tabs  514  that run along the edges  502  and  504 . Tabs  514  may be mounted to or disposed within a support structure or housing structure for MEMS component  204  in various ways, as discussed in further detail hereinafter (e.g., in connection with  FIGS.  15 - 17   ). 
     As shown in  FIG.  5   , the corrugated MEMS structure may include MEMS electrodes  510 , each forming a part of the single contiguous structure  501 , the part extending in a second dimension (e.g., the C dimension of  FIG.  5   ) perpendicular to the first dimension, between a corresponding pair of the alternating folds  500 . The alternating folds  500  may include upper folds extending from a first side of the MEMS electrodes  510  and between two adjacent MEMS electrodes  510 , and lower folds extending from an opposing second end of the MEMS electrodes  510  and between two adjacent MEMS electrodes  510 . The single contiguous structure  501  also extends, in a third dimension (e.g., the B dimension of  FIG.  5   ) perpendicular to the first dimension and the second dimension, from a first end  506  to a second end  508 . The corrugations in the corrugated MEMS structure of  FIG.  5    (e.g., each corrugation including an upper fold  500 , a lower fold  500 , and an intervening MEMS electrode  510 ) provide an efficient die area to SD ratio (e.g., a large acoustically active area in a small volume). 
     In various implementations of MEMS component  204 , the A, B, and C dimensions of the MEMS structure of  FIG.  5    can be aligned with the x, y, and z directions of  FIG.  4   , the B, A, and C dimensions of  FIG.  5    can be aligned with the x, y, and z directions of  FIG.  4   , or the C, A, and B dimensions of  FIG.  5    can be aligned with the x, y, and z directions of  FIG.  4    (as examples). 
     In one or more implementations, a MEMS component  204  can include one or more MEMS structures  410  and that are mounted between substrates.  FIGS.  6  and  7    illustrate examples in which MEMS structures  410  are disposed between substrates of a MEMS component. However, it should be appreciated that the examples of  FIGS.  6  and  7    are illustrative and that implementations of a MEMS component of a MEMS speaker that do not include substrates disposed on opposing sides of the MEMS component are also disclosed. For example, the MEMS component  410  of  FIG.  5    and/or in any of the examples of  FIG.  7 - 17  or  21    can be provided with or without substrates such as the substrates described in connection with  FIGS.  6  and  7   . 
     In the example of  FIG.  6   , an example of a MEMS component  204  is shown that includes a first substrate  400  having a first set of openings  402 , a second substrate  404  having a second set of openings  406  that are misaligned with the first set of openings, and a microelectromechanical systems (MEMS) structure  410  disposed between the first substrate  400  and the second substrate  404 . In this example in which substrates  400  and  404  are provided, the back volume  217  and the front volume  219  of  FIGS.  2  and  4    may be disposed outside the openings  402  and  406 , respectively. As shown in the example of  FIG.  6   , the first set of openings  402  may include multiple rows of openings, each row spaced apart along the y-direction of  FIG.  4   . Although not visible in the perspective view of  FIG.  6   , the second set of openings  406  may also include rows of openings spaced apart in the y-direction of  FIG.  4   . 
     As shown, MEMS component  204  may include multiple MEMS structures  410  that form a MEMS layer  408  between first substrate  400  and second substrate  404 . In the example of  FIG.  6   , MEMS layer  408  includes a MEMS structure  410  having an elongate dimension that extends in a direction parallel to the rows of openings  402  and the rows of openings  406  (e.g., along the y-direction of  FIG.  6   ). In the example of  FIG.  6   , one MEMS structure  410  is disposed at a location, in the x-direction of  FIG.  6    (e.g., in a direction perpendicular to the directions along which the rows of openings  402  and  406  are spaced apart), between each row of openings  402  and an adjacent row of openings  406  in the second substrate  404 . As shown in  FIG.  6   , MEMS component  204  may include multiple corrugated MEMS structures  410  disposed between the first substrate and the second substrate, where the multiple corrugated MEMS structures are misaligned with both the first plurality of openings  402  and the second plurality of openings  406 . 
     Each MEMS structure  410  may be a corrugated MEMS structure, as described above in connection with, e.g.,  FIG.  5   . As shown in the example of  FIG.  6   , a space  699  may be disposed between adjacent ones of the MEMS structures  410 . In this example, the actuation of MEMS structures  410  can be coordinated to create pressure differentials in the spaces  699  between the actuators. The pressure differences generated in the spaces  699  between the actuators, cause air to be pushed towards or pulled through the openings  402  and  406  to generate pressure differentials in the front and back volumes of the speaker. In one or more implementations, small spaces may be provided between the MEMS structures  410  and the first and second substrates  400  and  404 , to act as acoustic seals to avoid the pressure differentials in spaces  699  from escaping to the neighboring space  699 . Corrugations in the MEMS structures  410  can be arranged along the x-direction or the y-direction of  FIG.  4    in various implementations. 
     In the example of  FIG.  6   , the corrugated MEMS structures (e.g., MEMS structures  410 ) are spaced apart in a direction parallel to the second dimension (e.g., the C dimension) of the MEMS structures. In the example of  FIG.  6    in which MEMS structures  410  are disposed between first and second substrates  400  and  404 , the C, A, and B dimensions of  FIG.  5    are aligned with the x, y, and z directions. 
     In the example of  FIG.  6   , the corrugated MEMS structures (e.g., MEMS structures  410 ) are spaced apart in a direction parallel to the x-direction of  FIG.  4    (e.g., a direction parallel to the planes of the first and second substrates  400  and  404  and perpendicular to the direction in which the rows of openings are aligned in the substrates). In this example, the MEMS electrodes  510  of each MEMS structure  410  can be actuated by an application of an electrical input (e.g., an electrostatic input applied without using magnet and coil assemblies that are common in conventional speakers) to the electrodes, to generate various motions of the MEMS structure  410  to generate pressure differentials (e.g., in spaces  699 ) that pull and/or push air into and/or out of the openings  402  and  406 . 
     In the example of  FIG.  6   , an exemplary implementation of MEMS component  204  is described in which a MEMS layer  408 , including multiple MEMS structures  410 , is provided between first and second substrates  404 . However, it should also be appreciated that, in one or more implementations, multiple layers of corrugated MEMS structures can be stacked. 
       FIG.  7    illustrates an example in which MEMS component  204  includes a third substrate  700  disposed between the first substrate  400  and the second substrate  404 . In the example of  FIG.  7   , a MEMS structure  410  (e.g., a corrugated MEMS structure as described above in connection with  FIG.  5   ) is disposed (e.g., in a first MEMS layer  408 - 1 ) between the first substrate  400  and the third substrate  700 , and an additional corrugated MEMS structure (e.g., an additional MEMS structure  410 ) is disposed (e.g., in a second MEMS layer  408 - 2 ) between the third substrate  700  and the second substrate  404 . Each of the MEMS structures  410  shown in  FIG.  7    can be arranged in the alignment described above in connection with  FIGS.  5    and  6 , and can be operated in any of the various motions or modes of operation described herein. In the example of  FIG.  7   , the MEMS structure(s)  410  of the first MEMS layer  408 - 1  are aligned with the MEMS structures  410  of the second MEMS layer  408 - 2  to create a back volume  702  (e.g., corresponding to the back volume  217  of  FIGS.  2  and/or  4   ) on a first side of the MEMS structures  410  and a front volume  704  (e.g., corresponding to the front volume  219  of  FIGS.  2  and/or  4   ) on an opposing second side of the MEMS structures  410 . 
     In the example of  FIG.  7   , openings are not included in the substrates, as the MEMS actuators in this implementation can separate the front and back volumes. However it should be appreciated that each of the first substrate  400 , the second substrate  404 , and the third substrate  700  can be provided with openings that pass through from a first side of the substrate to a second side of the substrate to allow air to flow through the openings (e.g., responsive to the electrostatic actuation of the MEMS structures  410 ). For example, the third substrate  700  can include rows of openings that are aligned with the openings  402  in first substrate  400  and misaligned with the openings  406  in second substrate  404 , rows of openings that are aligned with the openings  406  in second substrate  404  and misaligned with the openings  402  in first substrate  400 , of rows of openings that are aligned with the openings  402  in first substrate  400  and aligned with the openings  406  in second substrate  404 , in various implementations. 
     The various motions of the MEMS structures  410  (e.g., in implementations in which the MEMS structure(s) are provided with or without the substrates of the examples of  FIGS.  6  and  7   ) can include breathing motions in which the various MEMS electrodes  510  are moved (e.g., out of phase) toward and away from each other along the A dimension, and out-of-plane motions in which the movements of the various MEMS electrodes  510  are coordinated to cause bulk out-of-plane motion of portions of the MEMS structure  410  (e.g., in a direction substantially parallel to the C dimension). The movements of the various MEMS electrodes  510  can be coordinated to cause breathing or bulk motion of portions of the MEMS structure  410  parallel to the first and second substrates  400  and  404  (e.g., in implementations in which first and second substrates are provided in the MEMS component). Mixed mode motions of the MEMS structures  410  can also be provided (e.g., achieved through a superposition of breathing and out-of-plane motions). Various operation modes for MEMS component  204  can be provided to generate a desired motion of the MEMS structures  410  using different boundary conditions for the MEMS structures and/or using different electrode pair assignments as described in further detail hereinafter. In this way, the MEMS structures  410  can be mounted in an arrangements that provide a low-power, compact speaker that includes an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane. 
     Each of the upper folds  500  or each of the lower folds  500  in the corrugated MEMS structure may resiliently couple together a pair of MEMS electrodes  510  that can be pushed together and/or pulled apart (e.g., in a breathing motion that generates pressure differentials above and below the corrugated MEMS structure) to generate sound. A MEMS speaker can include multiple corrugated MEMS structures such as MEMS structures  410  (e.g., that can also be operated in pairs). One or more corrugated MEMS structures can be mounted between front and back volumes (e.g., and/or between first and second substrates  400  and  404  with openings  402  and  406 ) to generate pressure differentials in the front and back volumes that generate sound. 
       FIG.  8    illustrates a cross-sectional side view of a MEMS structure  410 , taken along a line parallel to the A dimension of  FIG.  5   . In the example of  FIG.  5   , MEMS electrodes  510  can be seen extending (e.g., in the C dimension) between adjacent folds  500  (e.g., between a corresponding upper fold and a corresponding lower fold). MEMS structure  410  may be formed from a semiconductor material (e.g., including silicon, silicon nitride, polymer, metal, ceramic, polysilicon, single crystal silicon, silicon nitride including softer materials such as Parylene, polyimide, and/or a composite of these and/or other materials). MEMS electrodes  510  may be formed from the same material as the MEMS structure  410  itself and/or may include additional or other materials (e.g., metals applied to the MEMS structure by electroplating, evaporation, and/or sputtering processes). As shown in  FIG.  5   , each fold  500  may include an insulating element  800  that electrically insulates adjacent MEMS electrodes  510  from each other. Insulating element may be formed from, for example, silicon dioxide or other insulating materials, and may be formed at the center of each fold as illustrated in  FIG.  8    or elsewhere between MEMS electrodes  510 . In the example of  FIG.  8   , MEMS structure  410  is shown without an applied electrostatic input, showing how MEMS electrodes  510  may be evenly spaced (e.g., by the resilient forces of folds  500 ) in a resting state (e.g., in which no voltage is applied to the MEMS electrodes  510 ). 
       FIG.  9    illustrates cross-sectional views of the MEMS structure  410  of  FIG.  8   , with various operating voltages applied. As shown in  FIG.  9   , a DC voltage (e.g., Vdc) can be applied to MEMS structure  410  to move pairs  900  of adjacent MEMS electrodes  510  to a predetermined distance apart. As shown, the folds  500  between the electrodes may bend, flex, buckle, or otherwise deform (e.g., inward or outward) to allow the MEMS electrodes  510  to move to the desired spacing responsive to the DC voltage. 
     An alternating voltage (e.g., alternating between +Vac and −Vac) can be added to the DC voltage, Vdc, to cause the pairs of adjacent MEMS electrodes to move away from and toward each other. As indicated in  FIG.  9   , when the pairs  900  of MEMS electrodes  510  are moved apart from the DC spacing (e.g., by a reduced voltage Vdc−Vac), a positive pressure (e.g., P+) may be generated above the MEMS structure (e.g., in the front volume  219  and/or in a space  699 ), and a negative pressure (e.g., P−) may be generated below the MEMS structure (e.g., in the back volume  217  and/or in a neighboring space  699 ). When the pairs  900  of MEMS electrodes  510  are moved together from the DC spacing (e.g., by an increased voltage Vdc+Vac), a positive pressure (e.g., P+) may be generated below the MEMS structure (e.g., in the back volume  217  and/or in a neighboring space  699 ), and a negative pressure (e.g., P−) may be generated above the MEMS structure (e.g., in the front volume  219  and/or in a space  699 ). The pressure changes above and below the MEMS structure as shown can push (e.g., when the pressure is P+) and pull (e.g., when the pressure is P−) air into and out of a speaker housing and/or into and out of the spaces  699  between MEMS structures (e.g., in implementations that include two substrates with openings therein). The pressure differentials and the movement of air cause the generation of sound. The voltage Vac can be varied regularly and/or irregularly to generate desired frequencies of sound with MEMS component  204 . 
     The example of  FIG.  9    illustrates an actuation that consists of electrode pairs/unit actuators moving out of phase to generate a pressure gradient, in a first mode of operation corresponding to a breathing mode for MEMS structure  410 . It should also be appreciated that other operating modes (e.g., an out-of-plane mode and/or a mixed mode) are possible for MEMS structure  410 , depending on boundary conditions at the ends and/or edges of MEMS structure  410 . 
     For example,  FIG.  10    illustrates an out-of-plane mode of operation for a MEMS structure  410  in which bulk portions (e.g., groups of corrugations or all of the corrugations) of the MEMS structure  410  move between an in-plane state  1000  and an out-of-plane state  1002  (e.g., including motion along the C dimension defined by the MEMS electrodes  510  in the in-plane state  1000 ). A mixed mode operation of MEMS structure  410  can be performed using a linear superposition of both breathing mode operations (e.g., as described above in connection with  FIG.  9   ) and out-of-plane mode operations (e.g., as illustrated in  FIG.  10   ). Various boundary conditions for the ends and/or edges of MEMS structure  410  are described in further detail hereinafter, in connection with, for example,  FIGS.  15 - 17   . 
     Prior to the discussion of boundary conditions below, it should be appreciated that the arrangement of folds  500  shown in  FIGS.  8  and  9    is merely illustrative, and other arrangements can be used in one or more implementations. For example,  FIGS.  11  and  12    illustrate a portion of a MEMS structure  410  in implementations in which the folds  500  have different thicknesses. In the example of  FIG.  11   , folds  500  are arranged as in  FIGS.  8  and  9   . In the example of  FIG.  12   , the folds  500  are implemented as thinned folds  1200 , illustrating that the thickness of the folds  500  can be tuned to control the resilience of the corrugations to deformations caused by applied voltages. Thinned folds  1200  may have a thickness that is sufficiently small to allow the thinned folds  1200  to buckle when deformed by an applied voltage. 
       FIG.  13    illustrates a portion of a MEMS structure  410  in an implementation in which folds  500  are implemented as corrugated folds  1300 . Corrugated folds  1300  may allow the folds  500  to provide spring-like motions at the ends of the folds, with the spring-like (corrugated) portions of the fold coupled to MEMS electrodes  510  by rigid portions  1302  of the folds.  FIG.  14    illustrates a portion of a MEMS structure  410  in an implementation in which folds  500  are implemented as tented folds. As shown in  FIG.  14   , tented folds may be formed by linear rigid portions  1400  of MEMS structure  410 , the linear rigid portions  1400  meeting at a compliant apex  1402 . The implementations illustrated in  FIGS.  12 - 14    may help increase compliance of the folds and the available displacement of MEMS electrodes  510 . 
     As described above in connection with, for example,  FIGS.  8 - 10   , various boundary conditions for MEMS structures  410  can be provided, in various implementations, to arrange the MEMS structure  410  for various modes of operation and/or movement.  FIGS.  15 ,  16 , and  17    illustrate various examples of boundary conditions for MEMS structures  410  that can each be used in one or more implementations. 
     In the example of  FIG.  15   , the edges (e.g., first edge  502  and second edge  504  of  FIG.  5   ) of the MEMS structure  410  are fixed. In the example of  FIG.  15   , the tabs  514  of MEMS structure  410  are fixed to a corresponding resilient connector (e.g., a resilient connector  1502 ) that can flex to provide limited movement to the ends of the MEMS structure. In this example, the resilient connector  1502  extends between portions of a rigid connector structure  1500  of MEMS component  204 . Fixing the tab(s)  514  to resilient connector(s)  1502  can provide acoustic sealing and compliance to the structure. In one or more implementations, the rigid connector structure  1500  may be an edge structure that runs along an edge of MEMS component  204  and MEMS structure  410  to support the MEMS structure. In implementations in which MEMS component  204  is provided with a first substrate  400  and a second substrate  404  (e.g., as in the example of  FIG.  6   ), rigid connector structure  1500  may form a contiguous portion of a monolithic structure that forms a first substrate  400  and second substrate  404 , or may be a separate structure that is attached to the first substrate  400  and the second substrate  404 . 
       FIGS.  16  and  17    illustrate implementations of MEMS component  204  in which the MEMS structure  410  is provided with floating edges  502  and  504 . In these implementations, the available displacement of MEMS structure  410 , responsive to applied voltages, can be increased relative to a fixed edge implementation. In the example of  FIG.  16   , a portion  1600  of tab  514  is disposed in a recess  1602  in the rigid connector structure  1500 . In this example, one or more posts such as post  1604  can be provided that extend between a fold  500  of MEMS structure  410  and support structure  1605 . Support structure  1605  may be mounted to a portion of a speaker housing, may be formed by an integral portion of a speaker housing, or may be formed from a portion of a first substrate  400  and/or a second substrate  404  (e.g., in implementations in which first and second substrates are provided). In the example of  FIG.  16   , a single post  1604  extends to the support structure  1605  as a central beam at a symmetry axis of the MEMS structure. In other implementations, one or more additional posts  1604  can be provided as anchor beams at selected locations. Recess  1602  may extend along the entire length of MEMS structure  410  (e.g., such that the portions  1600  extend along the entire tab  514 ) or portions  1600  of tabs  514  may be extensions that extend into separate recesses  1602  disposed along the edge of MEMS structure  410 . In the example of  FIG.  16   , MEMS component  204  is provided with at least one anchor beam (e.g., post  1604 ) that extends from one of the plurality of alternating folds  500  to the support structure  1605 . However, it should be appreciated that two, or more than two anchor beams (e.g., posts  1604 ) can be provided extending from MEMS structure  410  to the one, two, or more than two support structures. For example, in one or more implementations, two or more attachment regions can be provided for runners and stabilization. In the example of  FIG.  16   , the recess  1602  may act as an air roller for portion  1600  of tab  514 , and can also provide an acoustic seal (e.g., due to high acoustic resistance in the narrow recess). 
       FIG.  17    illustrates another implementation of a floating edge for MEMS structure  410  in which a portion  1700  of tab  514  rests on a low friction film  1704  within a recess  1702  in rigid connector structure  1500 . In this example, the interface  1706  between low friction film  1704  and portion  1700  of tab  514  is a low friction interface that allows the tab to slide within the recess  1702 . In this example, the MEMS structure  410  is provided without posts that act as anchor beams. However, in one or more implementations, one or more posts  1604  can also be provided in the sliding edge implementation of  FIG.  17   . 
     In the examples of  FIGS.  15 - 17   , fixed and floating edges of a MEMS structure  410  are described. It should also be appreciated that ends  506  and  508  (see  FIG.  5   ) can also be fixed and/or floating ends. Fixed ends  506  and/or  508  can be provided by fixing discrete points on the ends of MEMS structure  410  to a connector structure such as a portion of connector structure  1500  that extends along the edges of MEMS structure  410 , to a substrate mounted adjacent to the MEMS structure, and/or by fixing the entire end of the MEMS structure  410  to the connector structure or the substrate. Fixed edges may be provided for MEMS structure  410  by fixing the tabs  514  at the edges of the MEMS structure to a support structure for MEMS component  204  (e.g., as shown in the example of  FIG.  15   ). In various implementations, MEMS structure  410  can be mounted in a free-free configuration in which the edges and ends of the MEMS structure are floating edges and ends, a free-fixed configuration in which the edges of the MEMS structure are floating edges and the ends of the MEMS structure are fixed ends, a fixed-free configuration in which the edges of the MEMS structure are fixed edges and the ends of the MEMS structure are floating ends, or a fixed-fixed configuration in which the edges and the ends of the MEMS structure are at least partially fixed. For example, in one or more implementations of the MEMS structure  410 , the MEMS structure  410  is formed from a single contiguous structure that extends, in a third dimension (e.g., the B dimension shown in  FIG.  5   ) perpendicular to the first dimension (e.g., the A dimension) and the second dimension (e.g., the C dimension), from a first end  506  to second end  508 , and at least one of the first end or the second end is fixed. As another example, in one or more implementations, the MEMS structure  410  is formed from a single contiguous structure that extends, in a third dimension (e.g., the B dimension shown in  FIG.  5   ) perpendicular to the first dimension (e.g., the A dimension) and the second dimension (e.g., the C dimension), from a first end  506  to second end  508 , and the first end  506  and the second end  508  are floating ends. 
     As described above in connection with, for example,  FIGS.  8  and  9   , the alternating folds  500  and the MEMS electrodes  510  may be densely packed along the first dimension of the MEMS structure (e.g., the A dimension) when no voltage is applied to the corrugated MEMS structure, with a spacing that allows the adjacent MEMS electrodes  510  to be operated in pairs  900 . However, in one or more implementations, a MEMS structure  410  may be provided in which some or all of the MEMS electrodes are widely spaced (e.g., to increase the low frequency range of the MEMS speaker). 
       FIG.  18    illustrates an implementation in which the MEMS electrodes  510  of MEMS structure  410  include widely spaced electrodes that operate as part of a set of electrodes that includes a fixed electrode extending from one of a first substrate such as the first substrate  400  or a second substrate such as the second substrate  404 . As shown in  FIG.  18   , MEMS component  204  may include one or more posts extending from at least one of the first substrate or the second substrate in a direction parallel to the second dimension (e.g., the C dimension) of the MEMS structure  410 . In the example of  FIG.  18   , MEMS component  204  includes posts  1800  extending from the first substrate  400  in the direction of the second substrate  404 , and posts  1802  extending from the second substrate  404  in the direction of the first substrate  400  (e.g., in a direction parallel to the second dimension of the MEMS structure  410 ). In this example, each of the widely spaced MEMS electrodes  510  can be operated in cooperation with a pair of posts  1800  and  1802  to actuate the MEMS electrodes  510 . As shown, each of the posts  1800  and  1802  extends from a corresponding substrate on a corresponding side of the MEMS structure  410  in the direction of the other substrate, without passing through the MEMS structure or reaching the other substrate. 
     As described above in connection with, for example,  FIGS.  8  and  9   , the alternating folds  500  and the MEMS electrodes  510  (e.g., the corrugations) of MEMS structure  410  may be evenly spaced apart along the first dimension of the MEMS structure (e.g., the A dimension) when no voltage is applied to the corrugated MEMS structure. However, in one or more other implementations, the folds  500  and the MEMS electrodes  510  may be unevenly spaced apart along the first dimension when no voltage is applied to the corrugated MEMS structure. 
       FIG.  19    illustrates a MEMS component  204  in an implementation in which a MEMS structure  410  includes MEMS electrodes  510  that are unevenly spaced apart along the first dimension when no voltage is applied to the corrugated MEMS structure. As shown in  FIG.  19   , a MEMS structure  410  may have one or more high frequency portions  1900  in which MEMS electrodes  510  are closely spaced for operation in pairs of MEMS electrodes (e.g., as described above in connection with  FIG.  9   ), and one or more low frequency portions  1902  in which MEMS electrodes  510  are widely spaced for operation in cooperation with fixed electrodes formed from posts  1800  and/or  1802  (e.g., as described above in connection with  FIG.  18   ). As shown, each MEMS electrode  510  in the low frequency portions  1902  may be disposed between a post  1800  extending from first substrate such as first substrate  400  and a second post extending from a second substrate such as second substrate  404 . As illustrated in  FIGS.  18  and  19   , each of the posts  1800  and  1802  may form a fixed electrode positioned adjacent at least a corresponding one of the plurality of MEMS electrodes  510 . For example, each MEMS electrode  510  may be actuated by a pair of fixed electrodes formed from a post  1800  and a post  1802 . 
       FIG.  20    illustrates a top view of a MEMS component  204  implemented with varied spacing of the MEMS electrodes  510 . In the example of  FIG.  20   , high frequency regions  2002  (e.g., having closed spaced electrodes such as in high frequency portions  1900  of  FIG.  19   ) are visible through some openings  402 , and low frequency regions  2000  (e.g., having widely spaced electrodes such as in low frequency portions  1902  of  FIG.  19   ) are visible through other openings  402 . In one or more implementations, the high frequency regions  2002  and low frequency regions  2000  can be implemented using the MEMS structure  410  and posts  1800  and  1802  of  FIG.  19   , and/or using multiple separate MEMS structures  410 , each with even electrode spacings (e.g., one or more MEMS structure  410  as shown in  FIG.  8    and one or more MEMS structures as shown in  FIG.  18   ). 
       FIG.  21    illustrates a flow diagram of an example process for operating a MEMS speaker in accordance with one or more implementations. For explanatory purposes, the process  2100  is primarily described herein with reference to the device  100  of  FIG.  1    or the device  300  of  FIG.  3   . However, the process  2100  is not limited to device  100  of  FIG.  1    or the device  300  of  FIG.  3   , and one or more blocks (or operations) of the process  2100  may be performed by one or more other components and other suitable devices (e.g., any electronic device including a MEMS speaker as described herein). Further for explanatory purposes, the blocks of the process  2100  are described herein as occurring in serial, or linearly. However, multiple blocks of the process  2100  may occur in parallel. In addition, the blocks of the process  2100  need not be performed in the order shown and/or one or more blocks of the process  2100  need not be performed and/or can be replaced by other operations. 
     At block  2102 , a voltage may be applied to a corrugated microelectromechanical systems (MEMS) structure (e.g., a MEMS structure  410  as described herein) that is disposed between a front volume such as front volume  219  and a back volume such as back volume  217 . In some examples, the MEMS structure may be disposed between a first substrate (e.g., first substrate  400 ) having first openings (e.g., a first plurality of openings  402 ) and a second substrate (e.g., substrate  404 ) having second openings (e.g., a second plurality of openings  406 ) that are misaligned with the first openings. In other examples, the MEMS structure may be openly exposed to the front and/or back volumes. 
     At block  2104 , the corrugated MEMS structure may be deformed, by the applied voltage, to generate sound with the speaker. In one or more implementations, the corrugated MEMS structure is formed by a single contiguous structure that extends, in a first dimension (e.g., the A dimension of  FIG.  5   ), from a first edge (e.g., first edge  502 ) to a second edge (e.g., second edge  504 ), and includes one or more alternating folds  500  disposed between the first edge and the second edge. The corrugated MEMS structure may include one or more MEMS electrodes  510 , each forming a part of the single contiguous structure, the part extending in a second dimension (e.g., the C dimension of  FIG.  5   ) perpendicular to the first dimension, between a corresponding pair of the alternating folds  500 . Deforming the corrugated MEMS structure may cause pressure differentials to be generated in the front and back volumes to generate the sound. In some examples, the pressure differential may be formed in spaces  699  between MEMS structures that are disposed between first and second substrates, the pressure differentials causing air to move through first openings in the first substrate and second openings in the second substrate to generate the sound. 
     Deforming the corrugated MEMS structure may generate a first pressure in the front volume and a second pressure in the back volume, the first pressure being different than the second pressure to generate the sound (e.g., and/or to cause the air to move). In some examples, deforming the corrugated MEMS structure may generate a first pressure in a first set of spaces  699  between the corrugated MEMS structures and a second pressure in a set of neighboring spaces  699  between the corrugated MEMS structures, the first pressure being different than the second pressure to cause the air to move. Deforming the corrugated MEMS structure may include causing pairs of the MEMS electrodes  510  to move toward or away from each other along the first dimension (e.g., as described above in connection with  FIG.  9   ). Deforming the corrugated MEMS structure may also, or alternatively, include deforming the single contiguous structure in a direction that is parallel to the second dimension (e.g., in an out-of-plane mode of operation as described above in connection with  FIG.  10   ). In one or more implementations, the direction that is parallel to the second dimension extends along a surface of the second substrate (e.g., as described above in connection with  FIG.  6   ). 
       FIG.  22    illustrates an electronic system  2200  with which one or more implementations of the subject technology may be implemented. The electronic system  2200  can be, and/or can be a part of, one or more of the devices  100  or  300  shown in  FIG.  1   . The electronic system  2200  may include various types of computer readable media and interfaces for various other types of computer readable media. The electronic system  2200  includes a bus  2208 , one or more processing unit(s)  2212 , a system memory  2204  (and/or buffer), a ROM  2210 , a permanent storage device  2202 , an input device interface  2214 , an output device interface  2206 , and one or more network interfaces  2216 , or subsets and variations thereof. 
     The bus  2208  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system  2200 . In one or more implementations, the bus  2208  communicatively connects the one or more processing unit(s)  2212  with the ROM  2210 , the system memory  2204 , and the permanent storage device  2202 . From these various memory units, the one or more processing unit(s)  2212  retrieves instructions to execute and data to process in order to execute the processes of the subject disclosure. The one or more processing unit(s)  2212  can be a single processor or a multi-core processor in different implementations. 
     The ROM  2210  stores static data and instructions that are needed by the one or more processing unit(s)  2212  and other modules of the electronic system  2200 . The permanent storage device  2202 , on the other hand, may be a read-and-write memory device. The permanent storage device  2202  may be a non-volatile memory unit that stores instructions and data even when the electronic system  2200  is off. In one or more implementations, a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) may be used as the permanent storage device  2202 . 
     In one or more implementations, a removable storage device (such as a floppy disk, flash drive, and its corresponding disk drive) may be used as the permanent storage device  2202 . Like the permanent storage device  2202 , the system memory  2204  may be a read-and-write memory device. However, unlike the permanent storage device  2202 , the system memory  2204  may be a volatile read-and-write memory, such as random access memory. The system memory  2204  may store any of the instructions and data that one or more processing unit(s)  2212  may need at runtime. In one or more implementations, the processes of the subject disclosure are stored in the system memory  2204 , the permanent storage device  2202 , and/or the ROM  2210 . From these various memory units, the one or more processing unit(s)  2212  retrieves instructions to execute and data to process in order to execute the processes of one or more implementations. 
     The bus  2208  also connects to the input and output device interfaces  2214  and  2206 . The input device interface  2214  enables a user to communicate information and select commands to the electronic system  2200 . Input devices that may be used with the input device interface  2214  may include, for example, alphanumeric keyboards and pointing devices (also called “cursor control devices”). The output device interface  2206  may enable, for example, the display of images generated by electronic system  2200 . Output devices that may be used with the output device interface  2206  may include, for example, printers and display devices, such as a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a flexible display, a flat panel display, a solid state display, a projector, or any other device for outputting information. One or more implementations may include devices that function as both input and output devices, such as a touchscreen. In these implementations, feedback provided to the user can be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
     Finally, as shown in  FIG.  22   , the bus  2208  also couples the electronic system  2200  to one or more networks and/or to one or more network nodes through the one or more network interface(s)  2216 . In this manner, the electronic system  2200  can be a part of a network of computers (such as a LAN, a wide area network (“WAN”), or an Intranet, or a network of networks, such as the Internet. Any or all components of the electronic system  2200  can be used in conjunction with the subject disclosure. 
     In accordance with some aspects of the subject disclosure, a speaker is provided that includes a front volume; a back volume; and a corrugated microelectromechanical systems (MEMS) structure disposed between the front volume and the back volume. 
     In accordance with other aspects of the subject disclosure, a method of operating a speaker is provided, the method including applying a voltage to a corrugated microelectromechanical systems (MEMS) structure that is disposed between a front volume and a back volume; and deforming, by the applied voltage, the corrugated MEMS structure to generate sound with the speaker. 
     In accordance with other aspects of the subject disclosure, an electronic device is provided that includes a speaker, the speaker including a front volume; a back volume; and a corrugated microelectromechanical systems (MEMS) structure disposed between the front volume and the back volume. 
     In accordance with other aspects of the subject disclosure, a speaker is provided that includes a first substrate having a first plurality of openings; a second substrate having a second plurality of openings that are misaligned with the first plurality of openings; and a corrugated microelectromechanical systems (MEMS) structure disposed between the first substrate and the second substrate. 
     In accordance with other aspects of the subject disclosure, a method of operating a speaker is provided, the method including applying a voltage to a corrugated microelectromechanical systems (MEMS) structure that is disposed between a first substrate having a first plurality of openings and a second substrate having a second plurality of openings that are misaligned with the first plurality of openings; and deforming, by the applied voltage, the corrugated MEMS structure to generate sound with the speaker. 
     In accordance with other aspects of the subject disclosure, an electronic device is provided that includes a speaker, the speaker including a first substrate having a first plurality of openings; a second substrate having a second plurality of openings that are misaligned with the first plurality of openings; and a corrugated microelectromechanical systems (MEMS) structure disposed between the first substrate and the second substrate. 
     Implementations within the scope of the present disclosure can be partially or entirely realized using a tangible computer-readable storage medium (or multiple tangible computer-readable storage media of one or more types) encoding one or more instructions. The tangible computer-readable storage medium also can be non-transitory in nature. 
     The computer-readable storage medium can be any storage medium that can be read, written, or otherwise accessed by a general purpose or special purpose computing device, including any processing electronics and/or processing circuitry capable of executing instructions. For example, without limitation, the computer-readable medium can include any volatile semiconductor memory, such as RAM, DRAM, SRAM, T-RAM, Z-RAM, and TTRAM. The computer-readable medium also can include any non-volatile semiconductor memory, such as ROM, PROM, EPROM, EEPROM, NVRAM, flash, nvSRAM, FeRAM, FeTRAM, MRAM, PRAM, CBRAM, SONOS, RRAM, NRAM, racetrack memory, FJG, and Millipede memory. 
     Further, the computer-readable storage medium can include any non-semiconductor memory, such as optical disk storage, magnetic disk storage, magnetic tape, other magnetic storage devices, or any other medium capable of storing one or more instructions. In one or more implementations, the tangible computer-readable storage medium can be directly coupled to a computing device, while in other implementations, the tangible computer-readable storage medium can be indirectly coupled to a computing device, e.g., via one or more wired connections, one or more wireless connections, or any combination thereof. 
     Instructions can be directly executable or can be used to develop executable instructions. For example, instructions can be realized as executable or non-executable machine code or as instructions in a high-level language that can be compiled to produce executable or non-executable machine code. Further, instructions also can be realized as or can include data. Computer-executable instructions also can be organized in any format, including routines, subroutines, programs, data structures, objects, modules, applications, applets, functions, etc. As recognized by those of skill in the art, details including, but not limited to, the number, structure, sequence, and organization of instructions can vary significantly without varying the underlying logic, function, processing, and output. 
     While the above discussion primarily refers to microprocessor or multi-core processors that execute software, one or more implementations are performed by one or more integrated circuits, such as ASICs or FPGAs. In one or more implementations, such integrated circuits execute instructions that are stored on the circuit itself. 
     Various functions described above can be implemented in digital electronic circuitry, 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, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), 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 multi-core 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 the purposes of the specification, the terms “display” or “displaying” means 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 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. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, RAM chips, hard drives, EPROMs, etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections. 
     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 sub-parts 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 here 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, 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, sub programs, 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 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 phrase 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 phrase such as an aspect may refer to one or more aspects and vice versa. A phrase 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 phrase 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 design. 
     In one aspect, a term coupled or the like may refer to being directly coupled. In another aspect, a term coupled or the like may refer to being indirectly coupled. 
     Terms such as top, bottom, front, rear, side, horizontal, vertical, and the like refer to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, such a term may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference. 
     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(f), 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: 20210216
Publication Date: 20230228
Grant Date: 20230228
Priority Date: 20200709
Inventors: HATIPOGLU, Gokhan
ILKORUR, ONUR I.
VIEITES, PABLO SEOANE
WILK, CHRISTOPHER
HRUDEY, PETER C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R7/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R19/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R19/013", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R19/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/021", "inventive": true, "first": true, "tree": "[]"}, {"code": "B81B3/0021", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R19/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "B81B3/0021", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R19/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R7/14", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 79020396