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US 10,948,688 B2Granted
Optical circuit switch mirror array crack protection
AssigneeGoogle Inc.
InventorKevin Y. Yasumura
Life of this patent
Estimating the term…
Abstract
Optical circuit switches have gained increased prominence in data centers in recent years given their ability to rapidly forward optical data signals without first converting those signals back into the electrical domain. Certain optical circuit switches are implemented using one or more arrays of single-axis or dual-axis gimballed micro-electro-mechanical system (MEMS) (MEMS) mirrors, whose orientations can be adjusted to direct light from an input port of the switch to a desired output port of the switch. Systems and methods according to the present disclosure relate to a microelectromechanical system (MEMS) mirror assembly with crack protection features such as a plurality of nibbles.
Claims16
A microelectromechanical system (MEMS) mirror assembly comprising:
- a mirror substrate defining portions of an actuator, a gimbal structure and a mirror cutout, the mirror cutout having an internal perimeter;
- a mirror including a mirror platform and a reflective surface, the mirror positioned within the mirror cutout of the mirror substrate and coupled to the mirror substrate by at least one stator, wherein:
- the mirror is supported by the gimbal structure;
- the mirror has a substantially planar surface defining a primary reflection plane of the mirror,
- the perimeter of the mirror, when the primary reflection plane of the mirror is parallel to the mirror substrate, is spaced from the outer perimeter of the mirror cutout by a gap around substantially the entire perimeter of the mirror except at the at least one stator,
- the size of the gap is substantially constant around the perimeter of the mirror other than at the at least one stator and at a plurality of nibbles defined in at least one of the mirror substrate and the mirror, wherein each of the nibbles comprises an extension of the gap into the mirror substrate and the mirror, and each nibble has a length of between about 50 microns and 200 microns, and a width of between about 50 microns and 200 microns,
- the mirror platform comprises:
- a first torsion beam and a second torsion beam extending from the mirror platform along a first axis of rotation;
- and
- the gimbal structure comprises:
- a third torsion beam and a fourth torsion beam extending from the gimbal structure along a second axis of rotation, perpendicular to the first axis of rotation, wherein,
- at least one of the plurality of nibbles is defined along a circumferential segment of the mirror platform extending between the first torsion beam and the second torsion beam such that the at least one of the plurality of nibbles locally increases the size of the gap between the mirror platform and the gimbal structure such that the gap extends into the mirror platform and the gimbal structure;
- or
- at least one of the plurality of nibbles is defined along a circumferential segment of the gimbal structure extending between the third torsion beam and the fourth torsion beam such that the at least one of the plurality of nibbles locally increases the size of the gap between the mirror platform and the gimbal structure such that the gap extends into the mirror platform and the gimbal structure.
11 more elements
A method of manufacturing a microelectromechanical system (MEMS) mirror assembly comprising:
- defining a cavity in a base substrate;
- coupling a mirror substrate to the base substrate such that a first side of the mirror substrate faces the cavity in the base substrate;
- defining portions of a MEMS actuator, a gimbal structure and a MEMS mirror having a mirror platform in the mirror substrate such that a first side of the MEMS mirror faces the cavity in the base substrate and a portion of the mirror substrate is spaced from the mirror by a gap and defining one or more nibbles in at least one of the mirror substrate and the mirror, wherein each of the nibbles comprises an extension of the gap into the mirror substrate and the mirror, and each nibble has a length of between about 50 microns and 200 microns, and a width of between about 50 microns and 100 microns, wherein a first torsion beam and a second torsion beam extend from the mirror platform along a first axis of rotation, a third torsion beam and a fourth torsion beam extend from the gimbal structure along a second axis of rotation, perpendicular to the first axis of rotation, wherein at least one of the plurality of nibbles is defined along a circumferential segment of the mirror platform extending between the first torsion beam and the second torsion beam such that the at least one of the plurality of nibbles locally increases the size of the gap between the mirror platform and the gimbal structure such that the gap extends into the mirror platform and the gimbal structure, or at least one of the plurality of nibbles is defined along a circumferential segment of the gimbal structure extending between the third torsion beam and the fourth torsion beam such that the at least one of the plurality of nibbles locally increases the size of the gap between the mirror platform and the gimbal structure such that the gap extends into the mirror platform and the gimbal structure;
- and
- disposing a reflective material on a second side of the MEMS mirror opposite the first side of the MEMS mirror.
2 more elements
Dependencies are inferred from the claim text.