US Patent 9581744 Optical stack and optical system

Integral optical stacks and optical systems including an image surface, a stop surface and an integral optical stack disposed between the image surface and the stop surface are described. The integral optical stack includes an optical lens, a partial reflector, a multilayer reflective polarizer and a quarter wave retarder. At least one chief light ray transmitted through the stop surface and the image surface passes through the stop surface at an incident angle of at least 40 degrees.