Diffractive optical elements with mitigation of rebounce-induced light loss and related systems and methods

• Main Authors: Bhargava, Samarth, Singh, Vikramjit, Luo, Kang, Deng, Xiaopei, Schmulen, Jeffrey Dean, Ricks, Neal Paul, Menezes, Marlon Edward, Messer, Kevin, Liu, Victor Kai, Dixon, Matthew Grant, Yang, Shuqiang, Xu, Frank Y
• Format: Patent
• Language: English
• Published: 20.07.2021
• Subjects: BLASTING; CALCULATING; COMPUTING; COUNTING; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; HEATING; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; LIGHTING; MECHANICAL ENGINEERING; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; WEAPONS

Display devices include waveguides with in-coupling optical elements that mitigate re-bounce of in-coupled light to improve overall in-coupling efficiency and/or uniformity. A waveguide receives light from a light source and/or projection optics and includes an in-coupling optical element that in-couples the received light to propagate by total internal reflection in a propagation direction within the waveguide. Once in-coupled into the waveguide the light may undergo re-bounce, in which the light reflects off a waveguide surface and, after the reflection, strikes the in-coupling optical element. Upon striking the in-coupling optical element, the light may be partially absorbed and/or out-coupled by the optical element, thereby effectively reducing the amount of in-coupled light propagating through the waveguide. The in-coupling optical element can be truncated or have reduced diffraction efficiency along the propagation direction to reduce the occurrence of light loss due to re-bounce of in-coupled light, resulting in less in-coupled light being prematurely out-coupled and/or absorbed during subsequent interactions with the in-coupling optical element.