Ultrasonic MEMS transmitter
First Claim
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.
1 Assignment
0 Petitions
Accused Products
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.
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Citations
22 Claims
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1. A transmitter comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transmitter comprising:
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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. - View Dependent Claims (8)
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9. A transmitter comprising:
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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. - View Dependent Claims (10, 11, 12, 13, 14)
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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:
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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. - View Dependent Claims (16, 17, 18, 19, 20)
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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:
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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. - View Dependent Claims (22)
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Specification