Methods and apparatus for optical image stabilization
Various embodiments provide an optical image stabilization system, comprising: a sensor configured to detect a disturbance signal; a processor; an actuator; and an actuator driver. The sensor can be configured to detect a disturbance signal, wherein the disturbance signal applies a force to a moving body, and wherein the force causes the moving body to displace. The processor can be configured to determine: a target position of the moving body according to the detected disturbance signal; and a corrected driving current according to the target position. The actuator can be configured to: receive the corrected driving current receive the corrected driving current; and position the moving body in response to receiving the corrected driving current, wherein the moving body is positioned in a direction opposite to that of the displacement. The actuator driver can be configured to controllably operate the actuator according to the corrected driving current.
1. An optical image stabilization system, comprising:
a sensor configured to detect a disturbance signal, wherein the disturbance signal applies a force to a moving body, and wherein the force causes the moving body to displace;
a processor configured to determine:
a target position of the moving body according to the detected disturbance signal in a first direction; and
a corrected driving current according to the target position and based on an angular rate in a second direction perpendicular to the first direction;
an actuator configured to:
receive the corrected driving current; and
position the moving body in response to receiving the corrected driving current, wherein the moving body is positioned in a direction opposite to that of the displacement; and
an actuator driver configured to controllably operate the actuator according to the corrected driving current
wherein the processor is further configured to:
calculate a current needed to produce a driving force for positioning the moving body according to the target position;
calculate a position compensation value corresponding to the first direction and based on an angular rate in the second direction perpendicular to the first direction; and
correct the current needed to produce the driving force for positioning the moving body according to the target position by the position compensation value to determine the corrected driving current.
2. The optical image stabilization system of claim 1 , wherein the moving body comprises a lens.
3. The optical image stabilization system of claim 1 , further comprising a position sensor configured to measure movements of the moving body.
4. The optical image stabilization system of claim 1 , wherein the actuator comprises a voice coil motor, and wherein the voice coil motor comprises a magnet configured to move the moving body.
5. The optical image stabilization system of claim 1 , further comprising a Hall sensor capable of detecting a magnetic field produced by the magnet.
6. A method for improving optical image stabilization, comprising:
detecting a disturbance signal applied to a moving body in a first direction, wherein the disturbance signal applies a force to the moving body, and wherein the force causes the moving body to displace;
converting the disturbance signal to an output signal;
generating an offset-corrected output signal from the output signal;
generating a phase-corrected output signal from the offset-corrected output signal;
generating a linearity corrected signal based on an angular rate in a second direction perpendicular to the first direction;
generating a corrected driving current according to the phase-corrected output signal and based on the linearity corrected signal; and
using the corrected driving current to position the moving body in a direction opposite to that of the displacement.
7. The method of claim 6 , wherein the output signal is an acceleration signal.
8. The method of claim 6 , wherein the offset-corrected output signal is free from an offset error.
9. The method of claim 6 , wherein the phase-corrected output signal is shifted in phase with respect to the offset-corrected output signal.
10. The optical image stabilization system of claim 1 , further comprising a Hall sensor capable of detecting a magnetic field produced by the magnet and to generate position data regarding a position of the moving body in the first direction; and
wherein the position compensation value is calculated based on the position data from the Hall sensor.
11. An optical image stabilization system, comprising:
a sensor configured to detect a first disturbance signal in a first direction and a second disturbance signal corresponding to a second direction perpendicular to the first direction, wherein the first disturbance signal and the second disturbance signal apply a force to a moving body, and wherein the force causes the moving body to displace;
a processor configured to determine:
a target position of the moving body according to the first disturbance signal in the first direction;
a current needed to produce a driving force for positioning the moving body according to the target position;
a position compensation value corresponding to the first direction and based on the second disturbance signal; and
a corrected driving current based on the current needed to produce the driving force and based on the position compensation value; and
an actuator configured to:
receive the corrected driving current; and
position the moving body in response to receiving the corrected driving current, wherein the moving body is positioned in a direction opposite to that of the displacement; and
an actuator driver configured to controllably operate the actuator according to the corrected driving current.
12. The optical image stabilization system of claim 11 , wherein at least one of the first disturbance signal and the second disturbance signal is an acceleration signal and another one of the of the first disturbance signal and the second disturbance signal is an angular rate.