SIGGRAPH 2008 > For Attendees > New Tech Demos > "Origami Optics" for Ultra-Thin Imagers

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"Origami Optics" for Ultra-Thin Imagers

Theme: Impact on Society
Hall H

Most camera lenses refract light, leading to the familiar cylindrical package geometry. For some applications in which extended focal length or reduced track length are required, concentric mirrors can be used to effectively reduce barrel length. Recent advances in diamond machining and image processing make it possible to take this approach to a new extreme.

With up to eight reflections, large ray angles, and a lens shaped more like a lens cap than a tube, this so-called Origami Optics approach allows us to squeeze long focal lengths into a thin package and still collect enough light for fast, sharp exposures.

This new class of imagers was developed under the MONTAGE program of the US Defense Advanced Research Projects Agency (DARPA). The resulting prototypes have yielded images comparable to images provide by much larger commercial "compact" cameras.

Enhanced Life
This project could make long-focal-length lenses practical and potentially less expensive in applications where space is at a premium and bulky refractive lenses are unsuitable. For example, this approach could be used to create a slim telephoto camera for cell phones.

Goal
The goal of this project was to fit telephoto lenses (20 mm and 40 mm focal length) into a 5 mm thickness while maintaining image quality and light collection comparable to those provided by large conventional refractive lenses.

Innovations
This project demonstrates that extremely precise modern fabrication techniques (in this case, single-point diamond turning) support creation of radically thin multi-element optics for imaging systems. The folded optics approach allows for optics up to 10x thinner than conventional refractive optics with high resolution and low F-numbers for sharp, fast exposures.

Vision
"Arc-sectioned" folded optics may be applied in conjunction with standard miniature refractive optics to create switched-zoom lenses for cell phones and other ultra-compact cameras. Full-aperture folded optics may be used for ultra-thin surveillance systems on UAV aircraft, and this technique could provide lightweight, fast, and less expensive lenses for thermal imaging systems.

Contributors
Eric Tremblay
Joseph Ford
University of California, San Diego

Ronald Stack
Rick Morrison
Distant Focus Corporation