Dynamic beam shaping for LED lighting

We describe an electrically tunable liquid crystal microlens array with a 65 mm clear aperture that allows the dynamic symmetric broadening of white light without mechanical movements. The fundamental mechanism of broadening is demonstrated to involve a spatial twist of molecular orientation. Continuous variations of the light divergence angle are obtained in a very large dynamic range (from 8 degrees to 50 degrees). Particular attention is paid to maintain the desired intensity and color temperature distributions over the angle. The developed lens may be used in various broadband illumination applications based on light-emitting diode-pumped phosphor sources. (c) 2023 Optica Publishing Group