Patent ID: 7106389

Claim:
An optical shifter, comprising: a first optical shifting section and a second optical shifting section, each of which is able to transmit an incoming light ray after having shifted the optical axis thereof, the first and second optical shifting sections being arranged such that a light ray that has been transmitted through the first optical shifting section enters the second optical shifting section, each of the first and second optical shifting sections comprising: a liquid crystal element including a liquid crystal cell, the liquid crystal cell selectively changing the polarization direction of the incoming light ray in response to a voltage applied thereto; and a birefringent element, which receives the light ray that has been transmitted through the liquid crystal element and which exhibits one of multiple different refractive indices according to the polarization direction of the incoming light ray, wherein the magnitude of shift caused by the first optical shifting section between the optical axes of the incoming and outgoing light rays thereof is substantially twice greater than that of shift caused by the second optical shifting section between the optical axes of the incoming and outgoing light rays thereof.