Projection display based on an optically addressed spatial light modulator using a bacteriorhodopsin thin film as a photochromic material

摘要

A novel laser projection display utilizing an optically addressed spatial light modulator (OASLM) is presented. The OASLM is based on the photochromic protein, bacteriorhodopsin, immobilized in a thin gelatin film. The photochromism of this material facilitates the light-induced switching of the optical absorption properties of the film. In this manner, the film can dynamically be switched between a purple- and yellow-colored state within 50 $mu@s. Furthermore, this material is capable of more than 10$+8$/ read-erase cycles without showing any sign of fatigue. This monochrome system is very suitable for radar displays, due to the high contrast of the projected images. Other possible applications include public information displays in airports and railway stations. The advantages of this projection system can be summarized as; (1) flicker-free graphics due to the temporal response of the OASLM causing no eye fatigue, (2) due to the molecular nature of the photochromic process, the spatial resolution is only limited by the scanners and projection lens, (3) as a result of the dynamic process in the OASLM, the system can be used at different ambient light levels by simply altering the intensity of the write laser and the read projection lamp simultaneously, (4) highly efficient use of the power from the projection lamp because it is actively pumping the photochromic process.