Miniature lens design and optimization with liquid lens element via genetic algorithm

This paper proposes a design and optimization method via (GA) genetic algorithm applied to a newly developed optical element: the liquid lens as a fast focus group. This design takes advantage of quick focus which works simultaneously with modern CMOS sensors in order to significantly improve image quality. Such improvement is important, especially for medical imaging technology such as laparoscopy. However, this optical design with a liquid lens element has not achieved success yet; one of the major reasons is the lack of anomalous dispersion glass and their Abbe number, which complicates the correction of aberrations, limits its availability. From the point of view of aberration theory, most aberrations, particularly in the axial chromatic and lateral color aberration of an optical lens, play the same role as the selection of optical glass. Therefore, in the present research, some optical layouts with a liquid lens are first discussed; next, genetic algorithms are used to replace traditional LDS (least damping square) to search for the best solution using a liquid lens and find the best glass sets for the combination of anomalous dispersion glass and materials inside a liquid lens. During optimization work, the 'geometric optics' theory and 'multiple dynamic crossover and random gene mutation' technique are employed. Through implementation of the algorithms proposed in this paper, satisfactory elimination of axial and lateral color aberration can be achieved.