Trajectory estimation for a MEMS reflector
A controller for a tiltable MEMS reflector is configured to oscillate the reflector about X axis or about X and Y axes, and to obtain information about current and past tilt angles. The controller is configured to evaluate tilt angles of the tiltable MEMS reflector at a later moment of time based on the previously obtained information about the tilt angles of the tiltable MEMS reflector at the different earlier moments of time. The controller may be further configured to energize the light source providing a light beam to the tiltable MEMS reflector at the later moment of time with brightness and color corresponding to the brightness and color of a pixel that will be painted by the tiltable MEMS reflector at the later moment of time. A statistical model may be combined with machine learning to accurately predict future tilt angles of the tiltable MEMS reflector.
1. A controller for a biresonant microelectromechanical system (MEMS) reflector, the controller configured for:
oscillating the biresonant MEMS reflector about X and Y axes by providing driving signals to the biresonant MEMS reflector;
obtaining information about tilt angles of the biresonant MEMS reflector at different moments of time;
determining a parameter of a statistical model defining a probability distribution of tilt angles of the biresonant MEMS reflector as a function of the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time; and
evaluating a tilt angle of the biresonant MEMS reflector based on the statistical model.
2. The controller of claim 1 , configured for obtaining the information about the tilt angles of the biresonant MEMS at the different earlier moments of time by obtaining sync signals at the different earlier moments of time, the sync signals indicating a pre-determined tilt angle of the biresonant MEMS reflector at the different earlier moments of time.
3. The controller of claim 2 , configured for obtaining the information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time by determining a phase of a resonant oscillation of the biresonant MEMS reflector at the different earlier moments of time.
4. The controller of claim 1 , configured for obtaining the information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time by measuring tilt angles of the biresonant MEMS reflector about at least one of the X axis or the Y axis at the different earlier moments of time.
5. The controller of claim 1 , configured for evaluating the tilt angle of the biresonant MEMS reflector based on a time difference between the different earlier moments of time when the biresonant MEMS reflector had a pre-determined tilt angle value.
6. The controller of claim 1 comprising a neural network configured to analyze the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time to determine the probability distribution of the statistical model.
7. A scanning projector display comprising:
a light source for providing a light beam;
a biresonant microelectromechanical system (MEMS) reflector optically coupled to the light source for scanning the light beam to provide an image in angular domain; and
a controller operably coupled to the light source and the biresonant MEMS reflector and configured for:
oscillating the biresonant MEMS reflector about X and Y axes by providing driving signals to the biresonant MEMS reflector;
obtaining information about tilt angles of the biresonant MEMS reflector at different moments of time;
determining a parameter of a statistical model defining a probability distribution of tilt angles of the biresonant MEMS reflector as a function of the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time;
evaluating a tilt angle of the biresonant MEMS reflector based on the statistical model;
determining which pixel of the image corresponds to the evaluated tilt angle of the biresonant MEMS reflector; and
operating the light source at a power level corresponding to brightness of the pixel.
8. The scanning projector display of claim 7 , wherein the biresonant MEMS reflector comprises a feedback circuit coupled to the controller and configured to provide sync signals thereto when a tilt angle of the biresonant MEMS reflector reaches a pre-determined value.
9. A method for controlling a microelectromechanical system (MEMS) reflector, the method comprising:
oscillating the MEMS reflector about at least one axis by providing driving signals to the MEMS reflector;
obtaining information about tilt angles of the MEMS reflector at different moments of time; and
determining a parameter of a statistical model defining a probability distribution of tilt angles of the biresonant MEMS reflector as a function of the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time;
evaluating a tilt angle of the MEMS reflector based on the statistical model.
10. The method of claim 9 , wherein obtaining the information about the tilt angles of the MEMS reflector for evaluating the tilt angle of the MEMS reflector comprises obtaining sync signals at the different earlier moments of time, the sync signals indicating a pre-determined tilt angle of the MEMS reflector at the different earlier moments of time.
11. The method of claim 9 , further comprising using a neural network to analyze the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time to determine the probability distribution of the statistical model.
12. The method of claim 11 , wherein the neural network is configured to determine the probability distribution of the statistical model based on measurements of tilt angles of the biresonant MEMS reflector about X and Y axes performed in a test setup.
13. The method of claim 9 , wherein the statistical model comprises a parametric model defining the tilt angle of the biresonant MEMS reflector as a function of the tilt angles of the biresonant MEMS reflector at the different earlier moments of time.
14. The method of claim 13 , wherein the parametric model comprises a model defining cross-coupling between oscillations of the biresonant MEMS reflector about X and Y axes.
15. The method of claim 14 , further comprising using a neural network to analyze the obtained information about the tilt angles of the biresonant MEMS reflector at the different earlier moments of time to determine a parameter of the model defining cross-coupling between oscillations of the biresonant MEMS reflector about X and Y axes.