Patent ID: 6259561
Filing Date: 2001-07-10
Classification: G02B

Abstract:
An optical system for diffusing illumination projected from a television or a display screen to provide said diffused illumination uniformly over an angle exceeding 45 degrees in at least one direction comprising:a diffractive element for diffracting said projected illumination to provide diffracted light; anda diffusing element which diffuses said diffracted light, in which the diffractive element provides said diffracted light having a diffraction period, wherein said diffractive element diffracts light in a plurality of diffraction orders, said diffusing element has a power spectrum having an angular width, and said diffraction period of said diffractive element provides an angular separation between a zeroeth of the diffraction orders and first of the diffraction orders approximately equal to one-half the angular width of the power spectrum of said diffusing element.