Camera comprising a roll correction actuator
A camera, consisting of a housing and an image sensor contained in the housing. The camera also has objective optics, which are coupled to the housing and which have an optical axis and which are configured to form an image on the image sensor. There is a mount, fixed within the housing, that has a frame, which holds the image sensor and is configured to rotate about the optical axis. The mount also has an actuator, which is configured to drive the frame to rotate about the axis. A controller is coupled to receive a signal indicative of a rotation of the housing about the optical axis and to drive the actuator to apply an opposing rotation to the frame.
1 . A camera, comprising:
a housing;
an image sensor contained in the housing;
objective optics, which are coupled to the housing and which have an optical axis and are configured to form an image on the image sensor;
a mount fixed within the housing and comprising:
a frame, which comprises a substrate whereon the image sensor is mounted, and which is configured to rotate about the optical axis; and
an actuator, which is configured to drive the frame to rotate about the axis and comprises a pair of voice coil motors coupled to the substrate, each voice coil motor comprising a magnet assembly comprising three linearly arranged permanent magnets with alternating polarities; and
a controller, which is coupled to receive a signal indicative of a rotation of the housing about the optical axis and to drive the actuator to apply an opposing rotation to the frame.
2 . The camera according to claim 1 , wherein neighboring magnets are separated by a non-ferromagnetic spacer.
3 . The camera according to claim 1 , wherein each voice coil motor comprises a coil assembly fixed to the substrate.
4 . The camera according to claim 3 , wherein the coil assembly comprises a pair of coils, lying in a common plane, connected in series and configured so that current through a first coil of the pair rotates in a clockwise direction and through a second coil of the pair rotates in a counterclockwise direction.
5 . The camera according to claim 4 , wherein neighboring magnets are separated by a non-ferromagnetic spacer aligning with a center of one of the pair of coils.
6 . The camera according to claim 1 , wherein a first voice coil motor of the pair is located at a first displacement from the optical axis, and a second voice coil motor of the pair is located at a second displacement from the optical axis, wherein the second displacement is equal in magnitude and opposite in direction to the first displacement.
7 . The camera according to claim 6 , wherein the controller is configured to drive the first voice coil motor to exert a first force, orthogonal to the optical axis, on the frame, and to drive the second voice coil motor to a exert a second force, equal in magnitude and opposite in direction to the first force, on the frame.
8 . The camera according to claim 1 , wherein the mount comprises a further frame fixed to the housing, each voice coil motor having the magnet assembly fixed to the further frame and a coil assembly fixed to the frame.
9 . A method, comprising:
providing a housing for a camera;
positioning an image sensor in the housing;
coupling objective optics, having an optical axis, to the housing and configuring the objective optics to form an image on the image sensor;
fixing a mount within the housing, the mount comprising:
a frame, which comprises a substrate whereon the image sensor is mounted, and which is configured to rotate about the optical axis; and
an actuator, which is configured to drive the frame to rotate about the axis and comprises a pair of voice coil motors coupled to the substrate, each voice coil motor comprising a magnet assembly comprising three linearly arranged permanent magnets with alternating polarities;
receiving a signal indicative of a rotation of the housing about the optical axis; and
in response to the signal, driving the actuator to apply an opposing rotation to the frame.
10 . The method according to claim 9 , wherein neighboring magnets are separated by a non-ferromagnetic spacer.
11 . The method according to claim 9 , wherein each voice coil motor comprises a coil assembly fixed to the substrate.
12 . The method according to claim 11 , wherein the coil assembly comprises a pair of coils, lying in a common plane, connected in series and configured so that current through a first coil of the pair rotates in a clockwise direction and through a second coil of the pair rotates in a counterclockwise direction.
13 . The method according to claim 12 , wherein neighboring magnets are separated by a non-ferromagnetic spacer aligning with a center of one of the pair of coils.
14 . The method according to claim 9 , and comprising locating a first voice coil motor of the pair at a first displacement from the optical axis, and locating a second voice coil motor of the pair at a second displacement from the optical axis, wherein the second displacement is equal in magnitude and opposite in direction to the first displacement.
15 . The method according to claim 14 , wherein driving the actuator comprises configuring the first voice coil motor to exert a first force, orthogonal to the optical axis, on the frame, and configuring the second voice coil motor to a exert a second force, equal in magnitude and opposite in direction to the first force, on the frame.
16 . The method according to claim 9 , wherein the mount comprises a further frame fixed to the housing, each voice coil motor having the magnet assembly fixed to the further frame and a coil assembly fixed to the frame.