Piezo-resistive sensing of mirror position in an optical switch
First Claim
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1. A MEMS device, comprising:
- a stationary part; and
at least one spring movably coupling the stationaly part and a movable part of the MEMS device and having first and second piezo-resistive layers, wherein the resistivity of the first piezo-resistive layer indicates position of the movable part with respect to the stationary part.
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Abstract
An integrated piezo-resistive sensor for determining mirror position in an optical switch. One or more piezo-resistive layers may be formed in silicon springs supporting a movable mirror in the switch. Change in resistivity of those layers due to spring deformation during mirror motion is measured and related to the mirror deflection angle. Information about the angle may be used to provide feedback to the motion actuator, which then may be operated to orient the mirror more accurately. A sensor'"'"'s sensitivity may be increased by appropriately orienting the springs with respect to the crystallographic axes of the silicon.
15 Citations
25 Claims
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1. A MEMS device, comprising:
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a stationary part; and
at least one spring movably coupling the stationaly part and a movable part of the MEMS device and having first and second piezo-resistive layers, wherein the resistivity of the first piezo-resistive layer indicates position of the movable part with respect to the stationary part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method comprising:
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measuring resistivity of a piezo-resistive layer of at least one spring movably coupling a stationary part and a movable part of a MEMS device, wherein the at least one spring has at least two piezo-resistive layers; and
determining position of the movable part with respect to the stationary part of the MEMS device based on the measured resistivity. - View Dependent Claims (17, 20, 21, 22)
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18. Apparatus comprising:
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means for measuring resistivity of a piezo-resistive layer of at least one spring movably coupling a stationary part and a movable part of a MEMS device, wherein the at least one spring has at least two piezo-resistive layers; and
means for determining position of the movable part with respect to the stationary part of the MEMS device based on the measured resistivity. - View Dependent Claims (19, 23, 24, 25)
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Specification