Diffractive optical element with undiffracted light expansion for eye safe operation

• Main Authors: Georgiou, Andreas, Kollin, Joel Steven, Kang, Sing Bing
• Format: Patent
• Language: English
• Published: 20.05.2025
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; AMUSEMENTS; CALCULATING; CARD, BOARD, OR ROULETTE GAMES; COMPUTING; COUNTING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; GAMES; GAMES NOT OTHERWISE PROVIDED FOR; HUMAN NECESSITIES; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; INDOOR GAMES USING SMALL MOVING PLAYING BODIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; SPORTS; TESTING; TRANSPORTING; VIDEO GAMES; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

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.