PATENT DOCUMENT

Publication Number: US-9457379-B2
Application Number: US-201313794417-A
Country: US
Kind Code: B2

Title: Ultrasonic MEMS transmitter

Abstract:
Ultrasonic transmitters that can be used for ranging in mobile devices are disclosed. In some examples, an ultrasonic transmitter device can be configured to transmit ultrasonic signals in multiple frequency bands. The transmitter can include multiple sets of ultrasonic transmitters, each capable of transmitting in a different frequency band. In other examples, frequency-adjustable ultrasonic transmitters can be used. The transmitters can be configured to change one or more of a length, mass, or tension of a membrane to change a resonant frequency of the membrane. In some examples, the transmitter can include a non-uniformly shaped membrane capable of vibrating at more than one resonant frequency. The ultrasonic transmitters can be included within a housing configured to control the flow of air within and out of the housing. The transmitter membrane can further be formed on a patterned substrate configured to increase the sound pressure levels produced by the transmitter.

Claims:
What is claimed is: 
     
       1. A transmitter comprising:
 a drum; 
 a membrane coupled to the drum; 
 a first electrode coupled to the drum; 
 a second electrode coupled to the membrane; and 
 a plurality of posts disposed within the drum, wherein the plurality of posts have non-uniform heights such that: 
 while the membrane is in a first configuration, a first post of the plurality of posts causes the membrane to have a first length; and 
 while the membrane is in a second configuration, a second post of the plurality of posts causes the membrane to have a second length, different from the first length; 
 wherein the membrane is configured to transmit an ultrasonic signal at a first frequency, corresponding to the first length, when a signal having a first DC voltage component is applied to the first electrode, and wherein the membrane is configured to transmit an ultrasonic signal at a second frequency, corresponding to the second length, when a signal having a second DC voltage component is applied to the first electrode. 
 
     
     
       2. The transmitter of  claim 1 , wherein a height of the first post of the plurality of posts is less than a height of the second post of the plurality of posts, and wherein the first post is positioned closer to a center of the membrane than the second post. 
     
     
       3. The transmitter of  claim 2 , wherein the membrane is configured to contact the first post when the signal having the first DC voltage component is applied to the first electrode, and wherein the membrane is configured to contact the second post when the signal having the second DC voltage component is applied to the first electrode. 
     
     
       4. The transmitter of  claim 1 , wherein the membrane is circular in shape, and wherein each of the plurality of posts form concentric circles within the drum. 
     
     
       5. The transmitter of  claim 1 , wherein the transmitter is a microelectromechanical system (MEMS) transmitter. 
     
     
       6. The transmitter of  claim 1  wherein the transmitter is enclosed within a housing, and wherein the housing comprises one or more dividers to control flow of air out of the housing. 
     
     
       7. A transmitter comprising:
 a drum; 
 a first membrane coupled to the drum; 
 a second membrane coupled to the drum; 
 a first electrode coupled to the drum; 
 a second electrode coupled to the first membrane; 
 a third electrode coupled to the first membrane opposite the second electrode; and 
 a fourth electrode coupled to the second membrane, wherein the first membrane is separate from the second membrane when a signal having a first DC voltage component is applied to the third electrode, and wherein the first membrane and second membrane are coupled together when a signal having a second DC voltage component is applied to the third electrode. 
 
     
     
       8. The transmitter of  claim 7 , wherein the transmitter is configured to transmit an ultrasonic signal having a first frequency when the signal having the first DC voltage component is applied to the third electrode, and wherein the transmitter is configured to transmit an ultrasonic signal having a second frequency when the signal having the second DC voltage component is applied to the third electrode. 
     
     
       9. A transmitter comprising:
 a drum; 
 a membrane coupled to the drum, the membrane having a shape including a length and a width, wherein the width is shorter than the length; 
 a first electrode coupled to the drum; and 
 a second electrode coupled to the membrane, wherein the membrane is configured to transmit an ultrasonic signal having a first frequency, corresponding to the width, in response to applying a first signal to the first electrode, and wherein the membrane is configured to transmit an ultrasonic signal having a second frequency, corresponding to the length, in response to applying a second signal to the first electrode. 
 
     
     
       10. The transmitter of  claim 9 , wherein the shape is an oval. 
     
     
       11. The transmitter of  claim 9 , wherein the shape is a rectangle. 
     
     
       12. The transmitter of  claim 9 , wherein the transmitter further comprises a third electrode and a fourth electrode coupled to opposite ends of the membrane along the length of the membrane. 
     
     
       13. The transmitter of  claim 9 , wherein the transmitter further comprises a third electrode and a fourth electrode coupled to opposite ends of the membrane along the width of the membrane. 
     
     
       14. The transmitter of  claim 9 , wherein the transmitter is included within a mobile phone, a tablet computer, a portable media player, or a laptop computer. 
     
     
       15. A method of transmitting at different frequencies using a transmitter comprising a drum, a membrane coupled to the drum, a first electrode coupled to the drum, a second electrode coupled to the membrane, and a plurality of posts of non-uniform height disposed within the drum, the method comprising:
 applying a first DC voltage component to the first electrode such that a first post of the plurality of posts causes the membrane to have a first length; 
 transmitting an ultrasonic signal at a first frequency corresponding to the first length; 
 applying a second DC voltage component to the first electrode such that a second post of the plurality of posts causes the membrane to have a second length; and 
 transmitting an ultrasonic signal at a second frequency corresponding to the second length. 
 
     
     
       16. The method of  claim 15 , wherein a height of the first post of the plurality of posts is less than a height of the second post of the plurality of posts, and wherein the first post is positioned closer to a center of the membrane than the second post. 
     
     
       17. The method of  claim 16 , wherein applying the first DC voltage component to the first electrode causes the membrane to contact the first post, and wherein applying the second DC voltage component to the first electrode causes the membrane to contact the second post. 
     
     
       18. The method of  claim 15 , wherein the membrane is circular in shape, and wherein each of the plurality of posts form concentric circles within the drum. 
     
     
       19. The method of  claim 15 , wherein the transmitter is a microelectromechanical system (MEMS) transmitter. 
     
     
       20. The method of  claim 15  wherein the transmitter is enclosed within a housing, and wherein the housing comprises one or more dividers to control flow of air out of the housing. 
     
     
       21. A method of transmitting at different frequencies using a transmitter comprising a drum, a first membrane coupled to the drum, a second membrane coupled to the drum, a first electrode coupled to the drum, a second electrode coupled to the first membrane, a third electrode coupled to the first membrane opposite the second electrode, and a fourth electrode coupled to the second membrane, the method comprising:
 applying a first DC voltage component to the third electrode such that the first membrane is separate from the second membrane; and 
 applying a second DC voltage component to the third electrode such that the first membrane and second membrane are coupled together. 
 
     
     
       22. The method of  claim 21 , further comprising:
 transmitting an ultrasonic signal having a first frequency when the signal having the first DC voltage component is applied to the third electrode; and 
 transmitting an ultrasonic signal having a second frequency when the signal having the second DC voltage component is applied to the third electrode.

Description:
FIELD 
     This relates generally to ultrasonic ranging and, more specifically, to ultrasonic microelectromechanical systems (MEMS) transmitters for ultrasonic ranging. 
     BACKGROUND 
     Mobile devices are very popular because of their portability, convenience, and versatile functionality. Such devices can include touch functionality that allows a user to perform various functions by touching a touch sensor panel using a finger, stylus, or other object at a location often dictated by a user interface (UI) being displayed by a display device; display functionality that allows a user to view on the display device a variety of information, either passively, such as reading text on the UI, or interactively, such as playing games or chatting in real time to another user; and communication functionality that allows a user to share video, audio, textual, and graphical data with others, through phone call, email, text messaging, chat rooms, music, streaming video, and the like. 
     Current networks allow mobile devices to connect to other devices in order to share information. In some cases, the devices can be far away from each other. In other cases, the devices can be in close proximity, within transmission capabilities of the individual device. 
     Taking advantage of device capabilities to easily and quickly facilitate communication therebetween when the devices are in close proximity is desirable. 
     SUMMARY 
     This relates to ultrasonic transmitters that can be used for ranging in mobile devices. For example, the ultrasonic ranging can be used to find proximate devices using ultrasound so as to communicate and share data between devices. In some examples, an ultrasonic transmitter package can be configured to transmit ultrasonic signals in multiple frequency bands. The transmitter package can include multiple sets of ultrasonic transmitters, each capable of transmitting in a different frequency band. In other examples, frequency-adjustable ultrasonic transmitters can be used. The transmitters can be configured to change one or more of a length, mass, or tension of a membrane in order to change a resonant frequency of the membrane. In some examples, transmitters can include non-uniformly shaped membranes capable of vibrating at more than one resonant frequency. The transmitter can further include one or more electrodes to adjust the length or width of the membrane. In some examples, the ultrasonic transmitters can be included within a housing configured to control the flow of air within and out of the housing. This can cause the transmitter to produce higher sound pressure levels. In some examples, the transmitter membrane can be formed on a patterned substrate configured to increase the sound pressure levels produced by the transmitter. 
     This summary is provided to introduce concepts in simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the disclosed subject matter and is not intended to describe each disclosed embodiment or every implementation of the disclosed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates ultrasonic ranging between mobile devices according to various examples of the disclosure. 
         FIG. 2  illustrates a mobile device capable of ultrasonic ranging according to various examples of the disclosure. 
         FIG. 3  illustrates ultrasonic frequency bands that can be used for ranging according to various examples of the disclosure. 
         FIG. 4  illustrates an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 5  illustrates a transmitter package including multiple sets of ultrasonic transmitters according to various examples of the disclosure. 
         FIG. 6  illustrates a length-adjustable ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 7  illustrates another length-adjustable ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 8  illustrates a length and tension-adjustable ultrasonic transmitter according to various examples of the disclosure. 
         FIGS. 9A-C  illustrate a length-adjustable ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 10  illustrates a mass-adjustable ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 11  illustrates a non-uniformly shaped ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 12  illustrates another non-uniformly shaped ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 13  illustrates a housing for an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 14  illustrates a patterned die substrate for an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 15  illustrates a computing system having an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 16  illustrates a mobile device that can include an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 17  illustrates another mobile device that can include an ultrasonic transmitter according to various examples of the disclosure. 
         FIG. 18  illustrates a laptop computer that can include an ultrasonic transmitter according to various examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings in which it is shown by way of illustration specific examples of the disclosure that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the various examples of the disclosure. 
     This relates to ultrasonic transmitters that can be used for ranging in mobile devices. For example, the ultrasonic ranging can be used to find proximate devices using ultrasound so as to communicate and share data between devices. In some examples, an ultrasonic transmitter device can be configured to transmit ultrasonic signals in multiple frequency bands. The transmitter can include multiple sets of ultrasonic transmitters, each capable of transmitting in a different frequency band. In other examples, frequency-adjustable ultrasonic transmitters can be used. The transmitters can be configured to change one or more of a length, mass, or tension of a membrane in order to change a resonant frequency of the membrane. In some examples, transmitters can include non-uniformly shaped membranes capable of vibrating at more than one resonant frequency. The transmitter can further include one or more electrodes to adjust the length or width of the membrane. In some examples, the ultrasonic transmitters can be included within a housing configured to control the flow of air within and out of the housing. This can cause the transmitter to produce higher sound pressure levels. In some examples, the transmitter membrane can be formed on a patterned substrate configured to increase the sound pressure levels produced by the transmitter. 
       FIG. 1  illustrates ultrasound ranging between two mobile devices. In the example of  FIG. 1 , system  100  can include device  102  and device  104  in close proximity. Device  102  can transmit ultrasonic signals to device  104  to determine the distance or range to device  104 . Similarly, device  104  can transmit ultrasonic signals to device  102 . Either device  102 ,  104  can initiate the transmission of the ultrasonic signals, while the other device can respond with transmission of its ultrasonic signals. The initiating device can use the two sets of ultrasonic signals, e.g., the signals it sent and the signals it received from the other device, and time of flight of the ultrasonic signals to determine the range between the devices. In some examples, both devices  102 ,  104  can be mobile. In some examples, either device  102 ,  104  can be mobile, while the other is fixed at a location. In some examples, both devices  102 ,  104  can be at fixed locations. 
     In addition to ultrasonic signals, device  102  can also transmit radio frequency (RF) signals to device  104  to assist with ranging, to communicate its presence and other information to device  104 , and/or to synchronize the two devices&#39; clocks. Similarly, device  104  can transmit RF signals to device  102 . 
     Device  102  can further transmit data, e.g., transaction data, channel and frequency data, device identification data, and so on, to device  104  in the ultrasound, RF, or other electromagnetic signals, such as optical signals. Similarly, device  104  can transmit data to device  102 . 
     Although the example of  FIG. 1  shows only two devices, it should be understood that any number of devices, e.g., 3, 4, or more, in close proximity can establish a de facto communication network, using ultrasound signals to determine range of devices, RF signals to synchronize devices, and either or both signals to transfer relevant data, depending on the capabilities of the devices. With a larger number of devices, ultrasound signals can be used for trilateration of all the devices, which can result in a three-dimensional map of the devices. In some examples, with the larger number of devices, one device can be a centralized device to gather information from and share information with the other devices, and estimate the three-dimensional map and orientations of the devices. 
     It should further be understood that other electromagnetic signals, e.g., infrared (IR), visible light, and the like, can also be used with ultrasound for ranging of proximate devices according to various examples. 
       FIG. 2  illustrates a mobile device capable of ultrasonic ranging. In the example of  FIG. 2 , device  102  can include ultrasonic transmitter  212  to transmit ultrasonic signals to proximate devices. In some examples, as will be explained in greater detail below, the ultrasonic transmitter  212  can include a transducer or any other suitable device for generating and transmitting ultrasonic signals. Device  102  can also include ultrasonic receiver  214  to receive ultrasonic signals from proximate devices. In some examples, the ultrasonic receiver  214  can be a microphone or any other suitable device for detecting ultrasonic signals. 
     Although the example of  FIG. 2  shows the transmitter and receiver as separate components, it should be understood that the two can be combined as a transceiver to both transmit and receive ultrasonic signals. It should further be understood that more than one transmitter and/or receiver can be used to provide stereo capabilities for the device. For example, multiple ultrasonic receivers can receive an ultrasonic signal at slightly different times, such that the time differences can be used to determine the relative orientation (or angle) of the proximate device. 
     In addition to ultrasonic components, device  102  can include an audio receiver  216  for detecting audio signals, e.g., voice, music, and other audible signals that can be inputted to the device. 
     Preferably, the frequencies of the ultrasonic signals used in finding a device range fall within a band that can provide adequate performance in the presence of any narrow or wideband interference sources and in typical indoor and outdoor conditions, e.g., temperature and humidity, and that can produce higher sound pressure levels (SPL).  FIG. 3  depicts example ultrasonic frequency bands that satisfy these preferences. In the example of  FIG. 3 , three frequency bands of operation with minimum SPL at 30 cm are shown—band 1 at 45-55 kHz, 110 dB SPL; band 2 at 60-70 kHz, 100 dB SPL; and band 3 at 85-95 kHz, 90 dB SPL. Each band is approximately 10 kHz wide and provides at least 2 frequency channels (e.g., 5 frequency channels spaced 2.5 kHz apart). These frequency bands can be preferable because of (a) generally low presence (or occupancy) of other narrow or wideband interference sources (highest occupancy being at other frequencies, e.g., 25, 27, 32, and 40 kHz), (b) low attenuation of signals at typical indoor humidity levels, e.g., humidity between 30-50%, and (c) high SPL. 
     Other configurations of the frequencies for ultrasonic signals used in ranging are also possible. In some examples, a single wideband can be used. In some examples, two wider frequency bands can be used. In some examples, more than three narrower frequency bands can be used. In some examples, more than 5 frequency channels can be used within each band. In some examples, less than 5 frequency channels can be used within each band. In some examples, the channels in each band can be contiguous. In some examples, the channels in each band can be separate. In some examples, the frequency bands can be spaced closer together. In some examples, the frequency bands can be spaced further apart. 
     Various types of transmissions can be used to transmit ultrasonic signals for ranging. For example, a tone burst signal can be used to transmit the ultrasonic signals, in which a constant tone amplitude of some duration is transmitted. Because the tone burst signal, in some examples, can be sensitive to interference, pulse shaping can be applied to the burst signal to provide a smoother transition between low and high voltages and to somewhat decrease its sensitivity to interference. In another example, a chirping signal can be used to transmit the ultrasonic signals, in which a sine-like wave of some duration is transmitted, where the signal can start at a lower frequency and then ramp up to higher frequencies over the duration of the signal. Because of the frequency changes, the chirping signal can be less sensitive to interference. The chirping signal can also provide higher precision ranging. In another example, a CDMA signal can be used to transmit the ultrasonic signals to allow multiple devices to transmit over the same channel or within the same frequency band. It should be understood that other transmission types can be used that are capable of transmitting ultrasonic signals for ranging devices. 
     To generate the ultrasonic signals described above, various types of transmitters can be used. For instance, in some examples, ultrasonic MEMS transmitters can be used. 
       FIG. 4  illustrates a cross-sectional view of a MEMS ultrasonic transmitter  400  that can be used in a mobile device for ranging. In the example of  FIG. 4 , transmitter  400  can include a drum  401  having a membrane  403  positioned over one end of the drum. Transmitter  400  can further include a first electrode  405  coupled to the underside of membrane  403 . A second electrode  407  can also be positioned within drum  401 , as shown in  FIG. 4 . In this configuration, an electrical signal can be applied to electrode  407 , causing a force to be exerted on electrode  405 . If the frequency of the applied electrical signal corresponds to the resonant frequency of membrane  403 , membrane  403  can be caused to vibrate by moving up and down in a spring-like fashion. This motion can create changes in air pressure around transmitter  400 , causing a sound having a frequency corresponding to the motion of membrane  403  to be generated. 
     The physical characteristics of MEMS transmitters, such as transmitter  400 , limit the range of frequencies that can be generated by the device. Typical MEMS transmitters can efficiently generate signals within a narrow spread within a single frequency band. Thus, to create multiple bands of signals, each having multiple channels as shown in  FIG. 3 , transmitters having different physical properties can be used. For example,  FIG. 5  illustrates an example 3-band MEMS transmitter package  500  that can be used to generate signals having frequency characteristics similar or identical to those shown in  FIG. 3 . Transmitter package  500  can generally include a single die substrate  501  having multiple transmitters  503  formed thereon. Transmitters  503  can include transmitters similar or identical to transmitter  400  shown in  FIG. 4 . However, the transmitter device  500  can include two or more (e.g., three) sets of transmitters  503  of varying sizes that are sensitive to different frequencies. For example, referring back to  FIG. 3  in which there are three frequency bands, substrate  501  can include a first set of transmitters  503  capable of generating ultrasonic signals within frequency band 1, e.g., 45-55 kHz; a second set of transmitters  503  capable of generating ultrasonic signals within band 2, e.g., 60-70 kHz; and a third set of transmitters  503  capable of generating ultrasonic signals within band 3, e.g., 85-95 kHz. Forming transmitters  503  within one ultrasonic transmitter package advantageously provides a more robust transmitter within a space constrained device. Additionally, by forming transmitters  503  on a single die, lateral (x/y) dimensions can be easily tailored to each transmitter type (length &amp; width) to create the different frequency responses. In this way, the MEMs process and film thicknesses are identical or at least substantially similar for each transmitter. 
     In some examples, the sets of transmitters  503  can be formed on separate die substrates  501 . For example, two sets of transmitters  503  can be formed on a single die substrate  501  while a third set of transmitters  503  can be formed on a second die substrate. In another example, each set of transmitters  503  can be formed on its own die substrate  501 . By forming transmitters  503  on separate dies, different MEMs processes and film thickness can be chosen to enable the different frequency ranges. For example, the lateral size dimensions could be the same, or also varied among the three transmitter designs. 
     While the transmitter package  500  can be effectively used to generate 3-bands of ultrasonic signals, the size of transmitter package  500  can be relatively large due to the use of multiple sets of transmitters  503  to generate the different frequency bands. 
       FIGS. 6-13  illustrate transmitters that can be adjusted to create multiple frequencies. Since the resonant frequency of a membrane of a MEMS transmitter depend at least in part on the mass, length, membrane thickness, and tension of the membrane, the transmitters shown in  FIGS. 6-13  include various mechanisms to adjust one or more of those factors. Using these transmitters, fewer transmitters can be used to generate the same signals produced by transmitter package  500 , thereby reducing the size of package  500 . 
       FIG. 6  illustrates a cross-section view of one example adjustable transmitter  600  that can be used to generate signals having different frequencies. Transmitter  600  can include a membrane  601  supported by posts  603  and  609  at each end. Transmitter  600  can further include posts  605  and  607  beneath membrane  601  and positioned closer to the center of membrane  601 . As shown in  FIG. 6 , the height of the posts decrease as the posts get closer to the center of membrane  601 . In this configuration, the movable length of membrane  601  can be adjusted by pulling down on membrane  601 , causing the bottom of membrane  601  to further contact post  605  or posts  605  and  607 . In doing so, the effective length of membrane  601  can be changed, since portions of membrane  601  outside of the inner-most contacting post will not vibrate. To pull down on membrane  601 , the DC voltage component of the signal applied to electrodes  613  of transmitter  600  can be increased, resulting in a larger attractive force between the electrodes  611  and  613 . Since the resonant frequency of membrane  601  can depend in part on the length of the membrane, the frequency of sound generated by transmitter  600  can be adjusted by selectively changing the DC voltage of the signal applied to the electrodes. For example, applying a signal having a larger DC voltage component to electrode  613  can cause membrane  601  to contact post  605 , thereby shortening the length of membrane  601 . The shorter length increases the resonant frequency of membrane  601 . Similarly, applying a signal having a smaller DC voltage component to electrode  613  can cause membrane  601  to disengage from post  605 , thereby increasing the length of membrane  601 . The larger length decreases the resonant frequency of membrane  601 . Alternatively, additional peripheral electrodes, located closer to posts  605  and  607 , can be used and biased with DC voltage to pull down the membrane into contact with posts  605  or  607 . 
       FIG. 7  illustrates a top-view of another example adjustable transmitter  700  that can be used to generate signals having different frequencies. Transmitter  700  can include a circular membrane  701 . Positioned below membrane  701  can be one or more posts  703 ,  705 , and  707 . Similar to transmitter  600 , the height of the posts can decrease as the posts get closer to the center of membrane  701 . Additionally, similar to transmitter  600 , the effective length of membrane  701  can be changed by adjusting a DC voltage level of the signal applied to the electrodes of transmitter  700 . In this way, the electrode coupled to the underside of membrane  701  can pull down on membrane  700 , causing portions of membrane  701  to contact posts one or more of  703 ,  705 , and  707 . Since the resonant frequency of membrane  701  depends in part on the length of the membrane, the frequency of sound generated by transmitter  700  can be adjusted by selectively changing the DC voltage of the signal applied to the electrodes. 
       FIG. 8  illustrates cross-section view of another example adjustable transmitter  800  that can be used to generate signals having different frequencies. Transmitter  800  can be similar to transmitter  600 , except that at least one of the posts  809  can be located away from the edge of membrane  801 . In particular, post  809  is a distance d away from the edge. This additional distance d of membrane  801  can be used to fine-tune the frequency generated by transmitter  800 . For example, the effective length of membrane  801  can be adjusted by changing the DC voltage component of the signal applied to electrode  813  as described above with respect to  FIG. 6 . This change can result in a relatively large change in the frequency of the sound generated by transmitter  800 . For instance, a change in effective length of membrane  801  can cause a change in frequency between the frequency bands shown in  FIG. 3 . To change between channels within the same frequency band, an electrode placed to the right of post  809  can be used to pull down on membrane  801 , thereby increasing the tension in membrane  801 . Since the resonant frequency of membrane  801  depends in part on the tension of the material, the frequency of sound generated by transmitter  800  can be adjusted by selectively changing the DC voltage component of a signal applied to an electrode below the  815 . For example, increasing the DC voltage component can cause an increase in tension in membrane  801 , thereby increasing the resonant frequency of membrane  801 . Similarly, decreasing the DC voltage component can cause a decrease in tension in membrane  801 , thereby decreasing the resonant frequency of membrane  801 . 
       FIGS. 9A-C  illustrate a cross-section of another example adjustable transmitter  900  that can be used to generate signals having different frequencies. Transmitter  900  is similar to transmitter  600 , except that the posts are built into membrane  901  of the transmitter. In particular, membrane  901  can include posts  905  and  907  positioned on the underside of membrane  901 . As shown in the various illustrations of  FIG. 9 , the effective length L of membrane  901  can be adjusted by changing a DC voltage level of the signal applied to electrode  909 . In this way, electrodes  909 ,  911  can be caused to pull down on membrane  901 , causing portions of membrane  901  to contact posts  905  and  907 . Since the resonant frequency of membrane  901  can depend in part on the length of the membrane, the frequency of sound generated by transmitter  900  can be adjusted by selectively changing the DC voltage component of the signal applied to electrode  909 . In some examples, an air or vacuum can be formed between membrane  901 , drum  903 , and substrate  913 . 
       FIG. 10  illustrates a cross-section view of another example adjustable transmitter  1000  that can be used to generate signals having different frequencies. Transmitter  1000  can include a first membrane  1001  having a first electrode  1003  coupled to the bottom of the first membrane  1001 . Transmitter  1000  can further include a second membrane  1007  having a second electrode  1009  and third electrode  1011  coupled to opposite sides of second membrane  1007 . Transmitter  1000  can further include a fourth electrode  1013  coupled to the bottom of the transmitter  1000  drum. In operation, a first frequency can be generated by applying a signal having a first DC voltage component to second electrode  1009 . The signal having the first DC voltage component applied to second electrode  1009  can cause first membrane  1001  to be physically separated from second membrane  1007 . Thus, when a signal is applied to fourth electrode  1013 , second membrane  1007  may vibrate at the first frequency. To generate a signal having a second frequency, a signal having a second DC voltage component can be applied to second electrode  1009 . The signal having the second DC voltage component applied to second electrode  1009  can cause electrodes  1003  and  1009  to be pulled together to couple together first membrane  1001  and second membrane  1007 . Since the resonant frequency of membrane  1007  depends in part on the mass of the membrane, the frequency of sound generated by transmitter  1000  can be adjusted by adding the mass of first membrane  1001  to second membrane  1007 . Thus, when a signal is applied to fourth electrode  1013 , second membrane  1007  and first membrane  1001  may vibrate at the second frequency. In this example, the second frequency is lower than the first frequency since an increase in mass decreases the resonant frequency. 
       FIG. 11  illustrates a top view of another example adjustable transmitter  1100  that can be used to generate signals having different frequencies. Transmitter  1100  can include membrane  1101  having a non-uniform shape. In particular, membrane  1101  can have an oval shape and can include a length L that is not equal to a width W. Since the resonant frequency at which membrane  1101  can vibrate depends in part on the length (or width) of the membrane, the non-uniformity of membrane  1101  can allow it to vibrate at multiple frequencies. By applying a signal to an electrode of transmitter  1100  at a frequency corresponding to length L, electrode  1103  on the underside of membrane  1101  can cause the membrane to vibrate at a first frequency. By applying a signal to the electrode of transmitter  1100  at a frequency corresponding to the width W, membrane  1101  can vibrate at a second frequency. 
     In some examples, transmitter  1100  can optionally include electrodes  1105 / 1107  and or  1109 / 1111 . Electrodes  1105  and  1107  can be used to change the first frequency (corresponding to length L) by pulling down on the edges of membrane  1101 , thereby changing the effective length L. Similarly, electrodes  1109  and  1111  can be used to change the second frequency (corresponding to width W (pulling down on the edges of membrane  1101 , thereby changing the effective width W. 
       FIG. 12  illustrates another example adjustable transmitter  1200  that can be used to generate signals having different frequencies. Similar to transmitter  1100 , transmitter  1200  includes membrane  1201  having a length L that is different from width W. Membrane  1201  can be supported by post  1203 . Transmitter  1200  can be operated in a manner similar to that described above with respect to transmitter  1100  to generate signals at difference frequencies. 
     In some examples, transmitter  1200  can optionally include electrodes  1205 / 1207  and or  1209 / 1211 . Electrodes  1205  and  1207  can be used to change the first frequency (corresponding to length L) by pulling down on the edges of membrane  1201 , thereby changing the effective length L. Similarly, electrodes  1209  and  1211  can be used to change the second frequency (corresponding to width W) by pulling down on the edges of membrane  1201 , thereby changing the effective width W. 
       FIG. 13  illustrates a cross-section view of an exemplary housing  1303  for transmitter  1300  that can be used to generate ultrasonic signals. Transmitter  1300  includes membrane  1301  enclosed within housing  1303 . Transmitter  1300  further includes dividers  1305 . Dividers  1305  can be used to control the flow of air within and out of housing  1303 . In some examples, divider  1305  can be positioned within housing  1303  such that the distance X between the center of membrane  1301  and aperture  1307  is half the distance between the distance 2× between the edges of membrane  1301  and aperture  1307 . In this way, the interference between the flow of air along the edges of drum  1303  and the air flow through the center of drum is reduced. The drum and divider design of transmitter  1300  can be used with any of the other transmitters disclosed herein. 
       FIG. 14  illustrates a cross-section view of an exemplary patterned die substrate for transmitter  1400  that can be used to generate ultrasonic signals. Transmitter  1400  includes membrane  1403  formed on substrate  1401 . Substrate  1401  can be patterned to include a channel  1405  beneath membrane  1403  that can extend to the bottom side of substrate  1401 . Channel  1405  can further extend up through substrate  1401  as shown in  FIG. 14 . In this way, as membrane  1403  vibrates up and down, air can be pushed up and away from transmitter  1400  when membrane  1403  flexes in the upward direction, and can force air out and away from transmitter  1400  via channel  1405  when membrane  1403  flexes in the downward direction. This design can produce higher SPLs than would be otherwise possible with conventional substrate designs. Substrate  1401  having channel  1405  can be used in combination with any of the transmitters disclosed herein. 
     Ultrasonic ranging can operate in a system similar or identical to system  1500  shown in  FIG. 15 . System  1500  can include instructions stored in a non-transitory computer readable storage medium, such as memory  1503  or storage device  1501 , and executed by processor  1505 . The instructions can also be stored and/or transported within any non-transitory computer readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer readable storage medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The instructions can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     The system  1500  can further include ultrasonic transmitter  1512 , ultrasonic receiver  1514 , and audio receiver  1516  coupled to the processor  1505 . The transmitter  1512  can include any of those described in  FIGS. 4 through 14 . The processor  1505  can process inputs to the transmitter  1512  and outputs from the receivers  1514 ,  1516  to perform actions based on ranges and other data associated with proximate devices. 
     The system  1500  can include touch panel  1507  coupled to the processor  1505 . Touch panel  1507  can have touch nodes capable of detecting an object touching or hovering over the panel. The processor  1505  can process the outputs from the touch panel  1507  to perform actions based on the touch or hover event. 
     It is to be understood that the system is not limited to the components and configuration of  FIG. 15 , but can include other or additional components in multiple configurations according to various examples. Additionally, the components of system  1500  can be included within a single device, or can be distributed between multiple devices. In some examples, the processor  1505  can be located within the touch panel  1507  and/or the imaging range finder  1509 . 
       FIG. 16  illustrates an exemplary mobile device  1600 , such as a tablet computer, that can include one or more ultrasonic transmitters according to various examples. 
       FIG. 17  illustrates an exemplary mobile device  1700 , such as a mobile phone or personal media player, that can include one or more ultrasonic transmitters according to various examples. 
       FIG. 18  illustrates an exemplary personal computer  1800  that can include one or more ultrasonic transmitters according to various examples. 
     While not shown, it should be appreciated that ultrasonic transmitters according to various examples described herein can also be used in other devices, such as televisions, peripheral television devices, and the like. 
     Therefore, according to the above, some examples of the disclosure are directed to a device comprising: a first set of transmitters configured to transmit an ultrasonic signal having a frequency within a first frequency band; and a second set of transmitters configured to transmit an ultrasonic signal having a frequency within a second frequency band. Additionally or alternatively to one or more of the examples disclosed above, the first frequency band can include frequencies between 45-55 kHz. Additionally or alternatively to one or more of the examples disclosed above, the second frequency band can include frequencies between 60-70 kHz. Additionally or alternatively to one or more of the examples disclosed above, the device can further include a third set of transmitters configured to transmit an ultrasonic signal having a frequency within a third frequency band. Additionally or alternatively to one or more of the examples disclosed above, the first, second, and third sets of transmitters can be formed on the same die substrate. Additionally or alternatively to one or more of the examples disclosed above, the first, second, and third sets of transmitters can each be formed on a different die substrate. Additionally or alternatively to one or more of the examples disclosed above, the third frequency band can include frequencies between 85-95 kHz. Additionally or alternatively to one or more of the examples disclosed above, the device can further include a fourth set of transmitters configured to transmit an ultrasonic signal having a frequency within a fourth frequency band. Additionally or alternatively to one or more of the examples disclosed above, each of the first, second, and third sets of transmitters can be configured to transmit signals in two or more different channels within their respective frequency bands. 
     Some examples of the disclosure are directed to a transmitter comprising: a drum; a membrane coupled to the drum; a first electrode coupled to the drum; a second electrode coupled to the membrane; and a plurality of posts disposed within the drum, wherein the plurality of posts can have non-uniform heights. Additionally or alternatively to one or more of the examples disclosed above, the membrane can be configured to transmit an ultrasonic signal at a first frequency when a signal having a first DC voltage component is applied to the first electrode and the membrane can be further configured to transmit an ultrasonic signal at a second frequency when a signal having a second DC voltage component is applied to the second electrode. Additionally or alternatively to one or more of the examples disclosed above, a height of a first post of the plurality of posts can be less than a height of a second post of the plurality of posts, wherein the first post can be positioned closer to the center of the membrane than the second post. Additionally or alternatively to one or more of the examples disclosed above, the membrane can be configured to contact the second post when the signal having the first DC voltage component is applied to the first electrode, wherein the membrane can be configured to contact the first post when the signal having the second DC voltage component is applied to the first electrode. Additionally or alternatively to one or more of the examples disclosed above, the membrane can be circular in shape and each of the plurality of posts form concentric circles within the drum. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can be a MEMS transmitter. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can be enclosed within a housing, wherein the housing can include one or more dividers to control the flow of air out of the housing. 
     Some examples of the disclosure are directed to a transmitter comprising: a drum; a first membrane coupled to the drum; a second membrane coupled to the drum; a first electrode coupled to the drum; a second electrode coupled to the first membrane; a third electrode coupled to the first membrane opposite the second electrode; and a fourth electrode coupled to the second membrane, wherein the first membrane can be separate from the second membrane when a signal having a first DC voltage component is applied to the third electrode, and wherein the first membrane and second membrane can be coupled together when a signal having a second DC voltage component is applied to the third electrode. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can be configured to transmit an ultrasonic signal having a first frequency when the signal having the first DC voltage component is applied to the third electrode and the transmitter can be further configured to transmit an ultrasonic signal having a second frequency when the signal having the second DC voltage component is applied to the third electrode. 
     Some examples of the disclosure are directed to a transmitter comprising: a drum; a membrane coupled to the drum, the membrane having a non-uniform shape; a first electrode coupled to the drum; and a second electrode coupled to the membrane, wherein the membrane can be configured to transmit an ultrasonic signal having a first frequency in response to applying a first signal to the first electrode, and wherein the membrane can be configured to transmit an ultrasonic signal having a second frequency in response to applying a second signal to the first electrode. Additionally or alternatively to one or more of the examples disclosed above, the non-uniform shape can be an oval. Additionally or alternatively to one or more of the examples disclosed above, the non-uniform shape can be a rectangle. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can further include a third electrode and a fourth electrode coupled to opposite ends of the membrane along the length of the membrane. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can further include a third electrode and a fourth electrode coupled to opposite ends of the membrane along the width of the membrane. Additionally or alternatively to one or more of the examples disclosed above, the transmitter can be included within a mobile phone, tablet computer, portable media player, or laptop computer. 
     Some examples of the disclosure are directed to a transmitter comprising: a patterned die substrate; and a membrane formed on a first side of the die substrate, wherein the patterned die can include a channel disposed beneath the membrane, and wherein the channel can extends from the from the first side of the die substrate to a second side of the die substrate opposite the first side, along the second side of the die substrate, and from the second side of the die substrate to the first side of the die substrate. 
     Although examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. For example, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described devices. Such changes and modifications are to be understood as being included within the scope of the various examples as defined in this Detailed Description and by the appended claims.

Metadata:
Filing Date: 20130311
Publication Date: 20161004
Grant Date: 20161004
Priority Date: 20121210
Inventors: AMM DAVID
YANG HENRY
LAST MATTHEW EMANUEL
Assignee: APPLE INC
CPC Classifications: [{"code": "G01S7/521", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01B17/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B06B1/0292", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01S15/74", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S7/521", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/003", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01B17/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B06B1/0292", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01S15/74", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50879539