On designing Blu-ray pickup head system with Liquid Crystal Lens

This research proposes a newly developed optical design and concept of active compensation on Blu-ray pick up head system with liquid crystal element. A liquid crystal (LC) lens with external input voltage is employed, that generates a symmetric non-uniform electrical field in the liquid crystal layer. This will direct liquid crystal molecules into appropriate distribution of gradient refractive indices, and result in convergence or divergence of specific light beam. By adjusting the voltages, a wide range of lens power is covered. The LC lens preserves its optical quality over the entire focus range, delivers fast and active compensation through optical design when errors occur. Simulation and tolerance analysis work have been done with Code V [1] software inclusive of defocus, tilt, decenter, and the related compensation. The results conclude that optical design with liquid crystal optics as active compensation device can eliminate aberrations compared to traditional ones.