Optical image stabilisation
First Claim
1. A camera apparatus comprising:
- a support structure;
a camera unit comprising an image sensor and a lens system for focussing an image on the image sensor, the camera unit being supported on the support structure in a manner allowing the camera unit to tilt relative to the optical axis of the lens system;
a plurality of SMA actuators arranged to drive tilting of the camera unit;
a sensor arrangement mounted on the camera unit and arranged to generate output signals representative of the movement of the camera unit; and
a control circuit arranged to generate drive signals and supply them to the SMA actuators, whereinthe control circuit is arranged to derive closed-loop control signals representative of a desired degree of variation in the power of the drive signals from the output signals of the sensor arrangement for reducing the movement of the camera unit, without dependence on any measurement of the resistance of the SMA actuators, andthe control circuit is arranged to generate the drive signals with powers that vary from set-point powers in correspondence with the closed-loop control signal.
1 Assignment
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Accused Products
Abstract
A camera apparatus capable of providing optical image stabilization comprises: a support structure; a camera unit comprising an image sensor and a lens system; a suspension system comprising a plurality of flexure elements supporting the camera unit on the support structure in a manner allowing the camera unit to tilt; and a plurality of SMA actuators. A sensor arrangement, whose output is used as the basis for generating drive signals, is mounted on the camera unit. A control circuit generates drive signals for the SMA actuators, by deriving closed-loop control signals representative of a desired degree of variation in the power of the drive signals from the output signals of the sensor arrangement without dependence on any measurement of the resistance of the SMA actuators, and generating the drive signals with powers that varies from a set-point power in correspondence with the closed-loop control signal.
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Citations
23 Claims
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1. A camera apparatus comprising:
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a support structure; a camera unit comprising an image sensor and a lens system for focussing an image on the image sensor, the camera unit being supported on the support structure in a manner allowing the camera unit to tilt relative to the optical axis of the lens system; a plurality of SMA actuators arranged to drive tilting of the camera unit; a sensor arrangement mounted on the camera unit and arranged to generate output signals representative of the movement of the camera unit; and a control circuit arranged to generate drive signals and supply them to the SMA actuators, wherein the control circuit is arranged to derive closed-loop control signals representative of a desired degree of variation in the power of the drive signals from the output signals of the sensor arrangement for reducing the movement of the camera unit, without dependence on any measurement of the resistance of the SMA actuators, and the control circuit is arranged to generate the drive signals with powers that vary from set-point powers in correspondence with the closed-loop control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of controlling a drive circuit to generate drive signals for SMA actuators that drive tilting of a camera unit comprising an image sensor and a lens system relative to a support structure from output signals of a sensor arrangement mounted on the camera unit, the method comprising:
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deriving closed-loop control signals representative of a desired degree of variation in the power of the drive signals from the output signals of the sensor arrangement without dependence on any measurement of the resistance of the SMA actuators, and generating power control signals for controlling the drive circuit to generate drive signals for the SMA actuators with powers that vary from a set-point power in correspondence with the closed-loop control signal.
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20. A controller for controlling a drive circuit to generate drive signals for SMA actuators that are arranged drive tilting of a camera unit comprising an image sensor and a lens system relative to a support structure, from output signals of a sensor arrangement mounted on the camera unit, wherein:
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the controller is arranged to derive closed-loop control signals representative of a desired degree of variation in the power of the drive signals from the output signals of the sensor arrangement without dependence on any measurement of the resistance of the SMA actuators, and the control circuit is arranged to generate power control signals for controlling the drive circuit to generate drive signals for supply to the SMA actuators with powers that varies from a set-point power in correspondence with the closed-loop control signal. - View Dependent Claims (21, 22, 23)
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Specification