DIFFRACTIVE OPTICAL ELEMENT WITH UNDIFFRACTED LIGHT EXPANSION FOR EYE SAFE OPERATION

摘要

Aspects of the subject disclosure are directed towards safely projecting a diffracted light pattern, such as in an infrared laser-based projection/illumination system. Non-diffracted (zero-order) light is refracted once to diffuse (defocus) the non-diffracted light to an eye safe level. Diffracted (non-zero-order) light is aberrated twice, e.g., once as part of diffraction by a diffracting optical element encoded with a Fresnel lens (which does not aberrate the non-diffracted light), and another time to cancel out the other aberration; the two aberrations may occur in either order. Various alternatives include upstream and downstream positioning of the diffracting optical element relative to a refractive optical element, and/or refraction via positive and negative lenses.

主权项

1. A system comprising:
a diffractive optical element (DOE) set comprising one or more optical elements that pass non-diffracted light that is not diffracted, the diffractive optical element set configured to diffract light from a light source that passes through the diffractive optical element set into a pattern of diffracted light, the diffractive optical element set further configured to aberrate the diffracted light; and a refractive optical element (ROE) optically coupled to the diffractive optical element set, the ROE configured to aberrate the non-diffracted light and the diffracted light, including to aberrate the diffracted light to cancel or substantially cancel aberration of the diffracted light by the diffractive optical element set.