Patent ID: 8542441
Filing Date: 2013-09-24
Classification: G02B,H04N

Abstract:
1. An optical element, comprising: a first color-selective dichroic filter having a first input surface, disposed to transmit a first color light beam perpendicular to the first input surface; a color-selective dichroic mirror disposed to intercept the first color light beam at an angle of approximately 45 degrees; a reflective polarizer disposed adjacent the color-selective dichroic mirror, opposite the first color-selective dichroic filter, a second color-selective dichroic filter having a second input surface disposed to transmit a second color light beam perpendicular to the second input surface, the second color light beam also intercepting the color-selective dichroic mirror at an angle of approximately 45 degrees, a first retarder disposed between the first color-selective dichroic filter and the reflective polarizer; a second retarder disposed between the second color-selective dichroic filter and the reflective polarizer, a third color-selective dichroic filter having a third input surface disposed to transmit a third color light beam perpendicular to the third input surface, the third color light beam also intercepting the color-selective dichroic mirror at an angle of approximately 45 degrees; and a third quarter-wave retarder aligned at an approximately 45 degree angle to the first polarization state, disposed facing the third color-selective dichroic filter, wherein the reflective polarizer is aligned to a first polarization state and each retarder comprises a quarter-wave retarder aligned at an approximately 45 degree angle to the first polarization state, and wherein the color-selective dichroic mirror is capable of transmitting a major portion of the third color light beam.