Liquid Crystal Lens Imaging Method Using 90° Twisted Nematic Liquid Crystal Cell Instead of Polarizer

This paper presents an imaging method of a liquid crystal (LC) lens using a 90 degrees twisted nematic LC (TNLC) cell instead of a polarizer. Two images are captured with the 90 degrees TNLC cell in the 0 degrees and 90 degrees optical rotatory states. By overlapping the two images and subtracting the defocused image obtained when the LC lens is not working, we can reduce the introduction of undesired low-frequency components of non-modulated light. In this way, the contrast of the final image is enhanced, and the noise generated by the original imaging processing without a polarizer is lessened. The proposed method is verified by experiments, and the results show that clear and well-focused images can be obtained without any polarizer.