US 7,321,458 B2
Apparatus for controlling the positioning of an optical dithering element
Stephen W. Marshall, Richardson, Tex. (US)
Assigned to Texas Instruments Incorporated, Dallas, Tex. (US)
Filed on Oct. 30, 2006, as Appl. No. 11/554,078.
Application 11/554078 is a division of application No. 10/752982, filed on Jan. 07, 2004, granted, now 7,130,105.
Prior Publication US 2007/0052968 A1, Mar. 08, 2007
Int. Cl. G02B 26/00 (2006.01)
U.S. Cl. 359—295  [359/291] 10 Claims
OG exemplary drawing
 
1. A system for controlling optical dithering comprising:
an actuator operable to repeatedly position an optical dithering element approximately between first and second positions;
a position sensor operable to sense the position of the optical dithering element at a plurality of sample times, and to generate a position error indicator signal for each of the plurality of sample times, the position error indicator signal having a first value responsive to the sensed position exceeding a desired setpoint for the position of the optical element, and having a second value responsive to the sensed position falling below the desired setpoint; and
a controller, coupled to the position sensor, the controller operable to generate a generally periodic waveform for controlling the actuator, operable to generate an error signature for a period of the waveform based on a plurality of the position error indicator signals generated by the position sensor for that period, and operable to modify the waveform for a later period of the waveform in response to the error signature.