Controlling a light beam using a phase-altering SLM device

摘要

A lighting device is arranged to produce a controllable light beam for illuminating a scene. The device comprises an SLM based system 305 comprising coherent light source (e.g. 110, figure 1) which illuminates an addressable phase-altering spatial light modulator (SLM) (e.g. 140, figure 1). The SLM imparts a selectable phase delay distribution to the incident light. The phase-modulated light is subject to a frequency (time) to spatial domain transformation using Fourier lens (120, figure 1) to form a light distribution at replay field 310. Projection optics 320 project the light distribution onto the scene as a controllable beam. The phase delay distribution may be controlled by selective control of the SLM elements to alter the light distribution and thus the field of illumination within the scene. The SLM may be a reflective liquid crystal on silicon (LCOS) device. The device may be implemented in a vehicle or automobile headlamp/headlight to provide controllable illumination of the road dependent upon driving conditions.