Electrically controlled optical system
The effective focal length of an optical system can be electronically controlled using switchable wave plates in conjunction with polarized light.
1. An electrically controlled optical system for controlling a focal length of an optical system in a light path comprising:
a switchable wave plate having two or more states, the switchable wave plate aligned to receive light input to the light path;
electrical means for controlling the state of the switchable wave plate;
a half-silvered mirror aligned to receive light from the switchable wave plate;
at least one refractive element downstream from the half-silvered mirror;
a polarization dependent mirror aligned to receive light from the at least one refractive element; and
one or more optical elements in the light path.
2. An apparatus for controlling a focal length of an optical system in a light path comprising:
one or more sets of electrically controlled optical systems according to claim 1 for directly passing or reflectively passing light along the optical system light path;
electrical control means for controlling the one or more sets of electrically controlled optical systems; and
one or more optical elements in the optical system light path.