Masafumi Ide

Compact multiple laser beam scanning module for high-resolution pico-projector applications using a fiber bundle combiner

We present a novel multiple laser beam scanning projection module using compact red-green-blue (RGB) fiber pigtailed laser modules for use in a high resolution pico-projector display system using a fiber bundle combiner in combination with a single MEMS mirror. This system can be used to create accurate multiple-projection images on a screen without overlaps or spaces among the projection images. The system uses very simple projection optics and has the potential to become a light engine unit for use in multiple projection systems, particularly those for light field displays. As such, light field display applications are also discussed.

Compact laser module with a high-speed liquid crystal attenuator for see-through display applications

Many kinds of head mount displays (HMDs) and head up displays (HUDs) have been appeared on the HMD / HUD early adaptor market. Many of them have become equipped with see-through capability and require dimming capability in response to ambient environmental conditions. We fabricated a high-speed liquid crystal (LC) variable attenuator using radially arranged electrodes and evaluated its basic characteristics.

Design concept of an FLC-NLC combined circular polarization switch for 3D laser pico-projectors

At present, LED-based pico-projectors are in widespread use. However, with the requirement for compact size, the demand for laser-light-source-based pico-projectors is expected to increase in the near future. Furthermore, picoprojectors with 3D capabilities are desired. 3D projectors employ either an active shutter system or a passive shutter system. We have proposed a novel combined circular polarization switch for 3D laser pico-projectors with passive shutter glasses, which consists of a high speed ferroelectric liquid crystal (FLC) linear polarization switch and a multiorder quarter-wave plate using a nematic liquid crystal (NLC) for RGB color chromatic dispersion compensation. In this study, we present a design concept of the polarization switch and we demonstrate that it affords increased bandwidth compared to the achromatic compensation method using an FLC with low order compensation films. The adjustment for each RGB laser wavelength using an additional polymer film working in the target range of 445 – 640 nm is also indicated. By using this novel design, when the permissible crosstalk level is 0.5%, the available wavelength range broadens from 59% to 91% of the target range. In addition, we fabricate a prototype based on the design concept and evaluate its crosstalk and 3D performance, which are important parameters for a 3D projector, in combination with a MEMS system. The proposed switch can be placed in the path of a combined RGB laser beam, and it is suitable for both imager-based and scanning-MEMS-based systems because of its simple structure and compact design.

A pixelized VOA based on liquid crystal on silicon

We have fabricated a 512-pixel liquid crystal VOA (variable optical attenuator) with biased PWM based on liquid crystal on silicon, using ITiO as a common electrode. The VOA is suitable for making tunable filters with low driver voltage.