A novel dual focus objective lens for DVD/CD pick-up head

Liu, Pei-Yih; Shieh, Han Ping D.; Ju, Jau-Jiu; Tsai, Shin-Ter; Yang, Tsung-Ming; Chang, Ting-Chen; Liu, Jiin-Song

doi:10.1109/20.667792

Cited by 14 publications

(1 citation statement)

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“…In contrast to conventional lenses that can only focus to a point at each time, a liquid tunable lens that can simultaneously focus at two different longitudinal points is fabricated and tested here. Double focusing lenses have found useful applications in DVD pick-up heads to achieve concurrent read-write functions [49] and to extend the depth of focus [50], among others. Double focusing lens has been developed with various methods such as using a birefringent lens [50], a deformable membrane with different thickness at different regions [34] and by end milling a metallic mold before using PDMS to replicate it [51].…”

Section: Liquid Tunable Double Focusing Lensmentioning

confidence: 99%

Diamond turning and soft lithography processes for liquid tunable lenses

Leung

Zhou

Huang

et al. 2010

J. Micromech. Microeng.

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Making use of the capability of high precision diamond turning in producing 3-dimensional free form optical surfaces with excellent surface finish, molds for various types of liquid tunable microlenses are fabricated. Subsequently, a rapid prototyping process known as soft lithography is applied to the fabricated mold to replicate multiple lens structures. This method provides an efficient and reliable way of generating rotationally symmetric free form optical surfaces that are otherwise difficult to produce with conventional methods such as lithography and etching methods. Using atomic force microscopy, white light interferometry and a mechanical profiler, it is verified that the surface quality and dimensional accuracy of the replicas are preserved. We demonstrate the practical usefulness of the proposed fabrication methods by developing and experimentally testing three different liquid tunable lenses, namely (1) a diffractive/refractive hybrid lens that reduces chromatic aberration within the visible spectrum, (2) a double focusing lens and (3) an aspherical lens that minimizes spherical aberration.

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