Patent ID: 7777932

Claim:
An imaging system comprising: an imaging lens unit, an imaging detector, and a birefringent element located between said imaging lens unit and said imaging detector, the system thereby providing in-focus imaging of objects located at both near-field and far-field ranges, the birefringent element having one of the following configurations: the birefringent element is made of a material in which birefringency was synthesized using spatial structure; the birefringent element is made of calcite or YVO 4 ; the birefringent element has a space varying width; the birefringent element is configured as a check board with different width of squares of the check board; the birefringent element has a curtain surface curvature, thus improving the depth of focus and reducing aberrations of focusing; the birefringent element is configured for correct aberrations created by the imaging lens unit; and birefringent element is configured and operable to provide time modulated birefringency thereof, the system being thereby configured an operable as an auto-focusing system having no moving parts.