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;
a coil member arranged in an elongated at least partially-cylindrical surface, wherein the elongated at least partially-cylindrical surface has a longitudinal axis coinciding with a rotation axis of the mirror axle and wherein the coil member is mounted via slots in the rear surface of the mirror; 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.
2 . The scanner of claim 1 , wherein the actuator assembly comprises:
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 having 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
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.
3 . The scanner of claim 2 , wherein the coil assembly comprises the coil member encapsulated in a polymeric material.
4 . The scanner of claim 2 , wherein the coil assembly comprises the coil member that forms a racetrack shape.
5 . The scanner of claim 2 , wherein the coil assembly comprises a printed circuit board (PCB) comprising a circuit trace forming a racetrack shape.
6 . The scanner of claim 2 , wherein the coil assembly 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.
7 . The scanner of claim 2 , wherein the coil assembly further includes 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.
8 . The scanner of claim 2 , 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.
9 . The scanner of claim 2 , wherein the second surface of the inner assembly body forms a cavity to accommodate a coil cross over portion of the coil assembly.
10 . The scanner of claim 2 , 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.
11 . The scanner of claim 1 , further comprising at least one mounting cap adapted to couple with and mount the scanner within the lidar system.
12 . 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.
13 . The scanner of claim 12 , wherein:
the polygon mirror is configured to rotate and produce one scan line of the scan pattern for each reflective surface of the polygon mirror; and
the mirror is configured to pivot and distribute the scan lines across the field of regard.
14 . The scanner of claim 13 , wherein:
the scan lines are directed horizontally; and
a scan rate of the mirror is slower near a middle of the field of regard so that more scan lines are located in the middle of the field of regard and fewer scan lines are directed at upper and lower portions of the field of regard.
15 . 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,
a coil member arranged in an elongated at least partially-cylindrical surface, wherein the elongated at least partially-cylindrical surface has a longitudinal axis coinciding with a rotation axis of the mirror axle and wherein the coil member is mounted via slots in the rear surface of the mirror, 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;
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.
16 . The lidar system of claim 15 , 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,
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.
17 . The lidar system of claim 15 , wherein the actuator assembly comprises:
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 having 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
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.
18 . The lidar system of claim 17 , wherein the coil assembly comprises the coil member encapsulated in a polymeric material.
19 . The lidar system of claim 17 , wherein the coil assembly comprises the coil member that forms a racetrack shape.
20 . The lidar system of claim 17 , wherein the coil assembly further includes 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.
21 . The lidar system of claim 17 , 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.
22 . The lidar system of claim 17 , wherein the second surface of the inner assembly body forms a cavity to accommodate a coil cross over portion of the coil assembly.
23 . The lidar system of claim 15 , further comprising at least one mounting cap adapted to couple with and mount the scanner within the lidar system.
24 . The lidar system of claim 15 , further comprising a housing at least partially enclosing one or more of the light source, the scanner, the receiver, and the controller.
25 . The lidar system of claim 15 , wherein the lidar system is integrated into a vehicle, wherein the lidar system is partially embedded into a surface of the vehicle, wherein a window of the lidar system protrudes from the surface.