Birefringent Crystal-based Wide-angle Polarization Interference Filter Theory, Experiment And Its Applications

Owing to many advantages, such as high aperture ratio, high resolution, low cost and low power consumption, LCOS display becomes a promising display technology in recent years. The projection display based on LCOS technology caters for the requirements of large-area image and high resolution, and grows up with vigor currently. Optical engine, the key system for imaging, has turned into a restraint factor for the development of LCOS projection display. In order to improve the efficiency of optical engine and simplify the optical architecture, a neotype color separation/recombination device based on polarization interference filter (PIF) is proposed for reflective LCOS projection display in this paper.Above all, the optical propagation characteristics in crystals are studied in detail. Derived from impulse response and sampling theorem in electronics, we establish the mathematical model of PIF constructed by a series of birefringent crystal retarders with arbitrary azimuths sandwiched between two polarizers. The non-singular extended 2 X 2 Jones matrix is deduced to give the precise description of angular property under normal and oblique incidence. Consequently, we draw a very important conclusion that the PIF is insensitive to the incidence, and has a large numerical aperture.Several optimization algorithms, such as genetic algorithm(GA), particle swarm optimization(PSO), simulated algorithm(SA) and adaptive simulated algorithm(ASA), are employed to design the PIF for the first time. On the basis of analyzing the several traditional algorithms, the efficient design method, the self-initiated weighted least squares(SWLS) combined with adaptive simulated annealing(ASA), are proposed explicitly for the design of PIF. This Chebyshev criterion based optimal approximation method has not only very fast computing speed but also high accuracy and good controllability. Besides, the determination of retardation value is given using mathematical method and physical sense. The tolerance property of PIF is analyzed detailedly, and spectral characteristic and angular property are tested by experiment. The tested and designed results are well matched. In particular, the good angular property of PIF is validated.In this paper, full color PIF is also analyzed, and neotype full color PIF with arbitrary azimuths for flat panel display(FPD) and projection display(PD) are elucidated in detail.Compared with traditional full color PIFs, this new full color PIF has better spectrum and larger color gamut.At the end of the paper, we extend the utilities of PIF and design several innovative polarization interference devices, such as broad-band polarization rotator, interleave and polarization vector integrating device. All these exploratory researches will promote the further development of PIF.