Patterned alignment liquid-crystal diffractive spatial light modulators and devices

摘要

Abstract: Recent advances in diffractive liquid crystal (LC) modulation structures for projection display service have generated diffractive spatial light modulator (SLM) devices capable of high performance in transmission and/or reflection. Patterning of the LC domain alignments has resulted in the generation of near perfect phase diffraction grating structures in the lC material, which can be controlled by a single electrode or by an array of segmented electrodes, such as an array of pixels. Consequently, diffractive artifacts from inter-electrode gaps can be eliminated and/or suppressed in a wider spectrum of applications with enhanced performance relative to previous structures. Transmissive diffractive LC modulators suitable for display or switch applications with modulation efficiencies in excess of 90 percent and contrast ratios of greater than 1500:1 in un-polarized light have been demonstrated. Operation of this type of modulator in reflection has also been verified and demonstrated. Comparison of patterned alignment, LC device performance with MEMS and other diffractive structures will be given. Extensions of these techniques to devices which include beam scanners and controllable diffractive optics will be proposed. !7