MEMS-based optical image stabilization
In one example, a camera is provided that includes: a plurality of MEMS electrostatic comb actuators, each actuator operable to exert a force on at least one lens; and an optical image stabilization (OIS) algorithm module operable to command the plurality of actuators to actuate the at least one lens responsive to motion of the camera.
1. A camera, comprising:
a plurality of electrostatic actuators configured to move at least one lens;
a plurality of position sensors corresponding to said plurality of actuators, each position sensor measuring a tangential displacement of its corresponding actuator;
a translator module operable to translate said tangential displacements from said position sensors into a displacement for said lens;
a fixed portion on which said plurality of electrostatic actuators are supported, wherein each of said plurality of electrostatic actuators comprises a movable portion configured to move, relative to said fixed portion, between a first position, in which said actuator is operable, and a second position, in which said actuator is non-operable; and
a latch configured to selectively latch said movable portion in said first position; and wherein
each actuator is configured to exert a tangential force on said at least one lens; and
said plurality of actuators tangentially actuate said at least one lens in response to a motion of said camera.
2. The camera of claim 1 , wherein said movable portion is configured to latch to said first position when an accelerated pulse is applied to said movable portion.
3. The camera of claim 1 , wherein said plurality of actuators are further configured to rotate said at least one lens when said plurality of actuators actuate said at least one lens tangentially in coordination.
4. The camera of claim 1 , further comprising a tool engaging feature coupled to said movable portion to facilitate movement of said movable portion from said second position to said first position.
5. The camera of claim 4 , further comprising a coplanar deployment lever coupling said tool engaging feature to said movable portion.
6. The camera of claim 5 , wherein:
said coplanar deployment lever is configured to pivot about a fulcrum at said movable portion; and
said coplanar deployment lever pivots to engage said latch when said movable portion moves to said first position.
7. The camera of claim 1 , wherein said actuators are electrostatic comb actuators comprising interdigitated fingers and said interdigitated fingers are configured to be moved apart to allow room for actuation when said movable portion moves from said second position to said first position.
8. An actuator, comprising:
a plurality of electrostatic actuators configured to move at least one lens;
a plurality of position sensors corresponding to said plurality of actuators, each position sensor measuring a tangential displacement of its corresponding actuator;
a translator module operable to translate said tangential displacements from said position sensors into a displacement for said lens;
a fixed portion on which said plurality of electrostatic actuators are supported to surround said at least one lens, wherein each of said plurality of electrostatic actuators comprises a movable portion configured to move, relative to said fixed portion, between a first position, in which said actuator is operable, and a second position, in which said actuator is non-operable; and
a latch configured to latch said movable portion in said first position.
9. The actuator of claim 8 , further comprising a tool engaging feature coupled to said movable portion to facilitate movement of said movable portion from said second position to said first position.
10. The actuator of claim 9 , further comprising a coplanar deployment lever coupling said tool engaging feature to said movable portion and being configured to pivot about a fulcrum at said movable portion, wherein said coplanar deployment lever pivots to engage said latch when said movable portion moves to said first position.
11. The actuator of claim 10 , wherein said coplanar deployment lever comprises a cam surface configured to engage said latch when said movable portion is in said first position.
12. The actuator of claim 10 , wherein said latch comprises a coplanar over-center latch configured to receive said cam surface of said coplanar deployment lever.
13. The actuator of claim 12 , wherein said coplanar over-center latch comprises a latch flexure configured to bias said coplanar over-center latch toward a lock position locking said coplanar deployment lever in said first position.
14. A system, comprising:
a lens;
a stage holding said lens within a curved aperture;
three integrally formed tangential actuators symmetrically disposed about said stage in a fixed portion, each tangential actuator operable to displace said stage in a direction tangential to a curve defined by said curved aperture, wherein each tangential actuator comprises a movable portion configured to move, relative to said fixed portion, between a first position, in which said tangential actuator is operable, and a second position, in which said tangential actuator is not operable; and
three position sensors corresponding to said three actuators, each position sensor measuring a tangential displacement of its corresponding actuator;
a translator module operable to translate said tangential displacements from said position sensors into a displacement for said lens;
a latch configured to latch said movable portion in said first position; and
a pull ring coupled to said movable portion to facilitate movement of said movable portion between said first position and said second position.
15. The system of claim 14 , wherein said curved aperture is a circle and said curve defined by said curved aperture is a circle.
16. The system of claim 14 , further comprising three V-shaped flexures corresponding to said three tangential actuators, wherein each tangential actuator couples to said stage through said corresponding V-shaped flexure.
17. The system of claim 16 , wherein each V-shaped flexure has a longitudinal axis aligned in said direction tangential to said curve.
18. The system of claim 14 , further comprising a coplanar deployment lever coupled to said pull ring, said lever configured to pivot about a fulcrum at said movable portion, wherein said coplanar deployment lever pivots to engage said latch when said movable portion moves to said first position.