Flat liquid crystal diffractive lenses with variable focus and magnification

Pouria Valley, Mohammad Reza Dodge, Jim Schwiegerling, David Mathine, Gholam Peyman, N. Peyghambarian

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Non-mechanical variable lenses are important for creating compact imaging devices. Various methods employing dielectrically actuated lenses, membrane lenses, and/or liquid crystal lenses were previously proposed1-4. Here we present tunable-focus flat liquid crystal diffractive lenses (LCDL) employing binary Fresnel zone electrodes fabricated on Indium-Tin-Oxide using conventional micro-photolithography. The phase levels can be adjusted by varying the effective refractive index of a nematic liquid crystal sandwiched between the electrodes and a reference substrate. Using a proper voltage distribution across various electrodes the focal length can be changed. Electrodes are shunted such that the correct phase retardation step sequence is achieved. If the number of 2π zone boundaries is increased by a factor of m the focal length is changed from f to f/m based on the digitized Fresnel zone equation: f = rm 2/2mλ, where rm is mth zone radius, and λ is the wavelength. The lenses operate at very low voltage levels (±2.5V ac input), exhibit fast switching times (20-150 ms), can have large apertures (>10 mm), and small form factor, and are robust and insensitive to vibrations, gravity, and capillary effects that limit membrane and dielectrically actuated lenses. Several tests were performed on the LCDL including diffraction efficiency measurement, switching dynamics, and hybrid imaging with a refractive lens. Negative focal lengths are achieved by adjusting the voltages across electrodes. Using these lenses in combination, magnification can be changed and zoom lenses can be formed. The promising results make LCDL a good candidate for non-mechanical auto-focus and zoom lenses.

Original languageEnglish (US)
Title of host publicationCurrent Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI
DOIs
StatePublished - Oct 28 2010
EventCurrent Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI - San Diego, CA, United States
Duration: Aug 1 2010Aug 3 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7786
ISSN (Print)0277-786X

Other

OtherCurrent Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI
CountryUnited States
CitySan Diego, CA
Period8/1/108/3/10

Keywords

  • Active or adaptive optics
  • Auto-focus
  • Diffractive lenses
  • Liquid-crystal devices
  • Non-mechanical optical zoom
  • Telescopes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Valley, P., Reza Dodge, M., Schwiegerling, J., Mathine, D., Peyman, G., & Peyghambarian, N. (2010). Flat liquid crystal diffractive lenses with variable focus and magnification. In Current Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI [77860H] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 7786). https://doi.org/10.1117/12.860963