Imaging system having coil on mirror actuator
A scanner for a lidar system is configured to direct emitted light to scan a field of regard of the lidar system in accordance with a scan pattern. The scanner includes a mirror and an actuator assembly. The mirror includes a reflective surface and a rear surface and is pivotable along a mirror axle. The actuator assembly is disposed along the rear surface of the mirror and is configured to exert a torque on the mirror to cause the mirror to pivot about the mirror axle.
1. A scanner for a lidar system, the scanner configured to direct emitted light to scan a field of regard of the lidar system in accordance with a scan pattern, the scanner comprising:
a mirror including a reflective surface and a rear surface and being pivotable along a mirror axle; and
an actuator assembly disposed along the rear surface of the mirror, the actuator assembly configured to exert a torque on the mirror to cause the mirror to pivot about the mirror axle, the actuator assembly comprising:
an inner assembly body having a first surface and a second surface, the first surface of the inner assembly body being positioned adjacent to the rear surface of the mirror and extending along a length thereof;
a coil assembly comprising:
a first surface and a second surface, the first surface of the coil assembly being positioned adjacent to the second surface of the inner assembly body; and
a first edge and a second edge opposite the first edge, wherein the rear surface of the mirror includes a first elongated slot to receive the first edge of the coil assembly and a second elongated slot to receive the second edge of the coil assembly; and
an outer assembly body having a first surface and a second surface, the first surface of the outer assembly body being positioned adjacent to the second surface of the coil assembly.
2. The scanner of claim 1 , wherein the coil assembly further comprises a coil member encapsulated in a polymeric material.
3. The scanner of claim 1 , wherein the coil assembly further comprises a coil member that forms a racetrack shape.
4. The scanner of claim 1 , wherein the coil assembly further comprises a printed circuit board (PCB) comprising a circuit trace forming a racetrack shape.
5. The scanner of claim 1 , wherein the coil assembly further comprises an electrically conductive material having a first coefficient of thermal expansion (CTE) and the mirror comprises a material having a second CTE, wherein the first CTE is approximately equal to the second CTE.
6. The scanner of claim 1 , further comprising at least one magnet positioned adjacent to or near the second surface of the outer assembly body, the at least one magnet configured to provide a magnetic field to the coil assembly.
7. The scanner of claim 1 , wherein the second surface of the inner assembly body forms a cavity to accommodate a coil cross over portion of the coil assembly.
8. The scanner of claim 1 , further comprising:
an electronic driver configured to provide a drive current to the coil assembly, the drive current comprising:
a low-amplitude current configured to cause the mirror to pivot about the mirror axle in a forward-scan direction, and
a high-amplitude square-wave current signal configured to rapidly slow a rate of rotation of the mirror and to cause the mirror to pivot about the mirror axle in a direction opposite the forward-scan direction.
9. The scanner of claim 1 , further comprising at least one mounting cap adapted to couple with and mount the scanner within the lidar system.
10. The scanner of claim 1 , further comprising:
a rotatable polygon mirror including a block having a first wall, a second wall, and a plurality of reflective surfaces extending between the first and second walls, the reflective surfaces being angularly offset from one another along a periphery of the block; and
a polygon mirror axle extending into the block through at least one of the first and second walls, about which the block rotates, the polygon mirror axle being orthogonal to the mirror axle.
11. A lidar system comprising:
a light source configured to emit light;
a scanner configured to direct the emitted light to scan a field of regard of the lidar system in accordance with a scan pattern, the scanner including:
a mirror having a reflective surface and a rear surface and being pivotable along a mirror axle;
an actuator assembly disposed along the rear surface of the mirror, the actuator assembly configured to exert a torque on the mirror to cause the mirror to pivot about the mirror axle, the actuator assembly comprising:
an inner assembly body having a first surface and a second surface, the first surface of the inner assembly body being positioned adjacent to the rear surface of the mirror and extending along a length thereof;
a coil assembly comprising:
a first surface and a second surface, the first surface of the coil assembly being positioned adjacent to the second surface of the inner assembly body; and
a first edge and a second edge opposite the first edge, wherein the rear surface of the mirror includes a first elongated slot to receive the first edge of the coil assembly and a second elongated slot to receive the second edge of the coil assembly; and
an outer assembly body having a first surface and a second surface, the first surface of the outer assembly body being positioned adjacent to the second surface of the coil assembly;
a receiver configured to detect at least a portion of the emitted light scattered by one or more remote targets; and
a controller configured to control motion of at least the mirror to scan the emitted light along the scan pattern.
12. The lidar system of claim 11 , wherein the scanner further includes:
a rotatable polygon mirror having a block having a first wall, a second wall, and a plurality of reflective surfaces extending between the first and second walls, the reflective surfaces being angularly offset from one another along a periphery of the block; and
a polygon mirror axle extending into the block through at least one of the first and second walls, about which the block rotates, the polygon mirror axle being orthogonal to the mirror axle.
13. The lidar system of claim 11 , wherein the coil assembly further comprises a coil member encapsulated in a polymeric material.
14. The lidar system of claim 11 , wherein the coil assembly further comprises a coil member that forms a racetrack shape.
15. The lidar system of claim 11 , further comprising at least one magnet positioned adjacent to or near the second surface of the outer assembly body, the at least one magnet configured to provide a magnetic field to the coil assembly.
16. The lidar system of claim 11 , wherein the second surface of the inner assembly body forms a cavity to accommodate a coil cross over portion of the coil assembly.
17. The lidar system of claim 11 , further comprising at least one mounting cap adapted to couple with and mount the scanner within the lidar system.
18. The lidar system of claim 11 , further comprising a housing at least partially enclosing one or more of the light source, the scanner, the receiver, and the controller.