Patent ID: 6671096
Filing Date: 2003-12-30
Classification: G02B

Abstract:
A diffractive optical element for white light, comprising a plurality of layers of optical materials and having a relief pattern constituting a diffraction grating that has a first sectional profile in a central region that is different from a second sectional profile in a peripheral region, said diffraction grating formed at one or more cementing interfaces, each cementing interface being between a respective pair of layers of said plurality of layers, the optical materials of a respective pair of layers differing from each other,wherein a grating height of the relief pattern constituting the diffraction grating is defined by the following formula: h=&lgr;/|nâˆ’nâ€²|â€ƒwhere h represents the grating height of the relief pattern constituting the diffraction grating; &lgr; represents a selected design wavelength; n represents a refractive index of an optical material abutting a first one of the one or more interfaces from an object side for light of a wavelength &lgr;; and nâ€² represents a refractive index of an optical material abutting the first one of the one or more interfaces from an image side for light of the wavelength &lgr;, wherein the first sectional profile is a blaze-form sectional profile and the second sectional profile is a triangular sectional profile.