Patent ID: 7061680
Filing Date: 2006-06-13
Classification: G02B

Abstract:
1. A method of adjusting contrast in an optical system between an object and surrounding background, comprising: providing a non-polarizing light source in front of an object and illuminating the object with non-polarized light, the illuminated object reflecting non-polarized light; providing a reflective polarizer having a reflective axis behind the object, the reflective polarizer being configured to receive non-polarized light from the non-polarizing light source and reflect polarized light; providing a transmissive polarizer having a transmissive axis in front of the object, the transmissive polarizer being configured to receive the non-polarized light reflected from the object and the polarized light reflected from the reflective polarizer; and adjusting the contrast between the object and the surrounding background by adjusting the transmissive axis of the transmissive polarizer relative to the reflective axis of the reflective polarizer.