Telescopes make bug-eye optics
Technology Research News
latest wave of miniaturization -- optics -- has brought the world the cell
phone camera, but such small camera lenses produce relatively low quality
Researchers working to overcome this physical limitation are following
nature's lead by developing arrays of tiny lenses that work like insects'
compound eyes. Arrays of microlenses are a route to smaller and cheaper
optics because they can be made in bulk using chipmaking techniques.
Researchers at the Fraunhofer Institute for Applied Optics and Precision
Engineering in Germany, SUSS MicroOptics SA and the University of Neuchâtel
in Switzerland have developed a prototype artificial compound eye made from
three stacked sets of microlenses that form an array of tiny telescopes.
The microtelescope array magnifies relatively distant objects within
a wide field of view, said Jacques Duparré, a physicist at the Fraunhofer
Institute. Each telescope captures a portion of the field of view and the
array is aligned to combine these elemental images to form a single complete
The artificial compound eye could be used for camera phones, infrared
vision systems and optical sensors, said Duparré. "Compact vision is needed
everywhere," he said.
The approach could make optics as inexpensive and compact as electronics,
said Duparré. "Cameras in toys are in sight."
The researchers made the microtelescope array by etching the lenses
from fused silica. The researchers' 2-millimeter thick prototype consists
of 21 microtelescopes that each contain three lenses. The array has a 70-
by 10-degree field of view and produces a 4.5- by 0.5-millimeter image.
Individual lenses range from 8 to 20.2 microns thick and from 73.2-micron
disks to ellipses 311.2 microns long. A micron is one thousandth of a millimeter.
The lenses in the top array of focusing lenses are elliptical. The
middle, or field, lenses are circular and aligned with square openings in
a mask. The bottom, relay lenses are circular and are aligned with circular,
offset openings in another mask.
Ideally, the lens alignments and mask opening configurations seamlessly
combine the elemental images. The researchers' prototype, however, has gaps
in some places and overlaps in others. Sixteen of the 21 microtelescopes
in a prototype worked, yielding a 63-degree field of view, said Duparré.
The researchers plan to iteratively improve the alignments to correct these
problems, he said.
The next step is to arrange microlenses in a circular array that
mimics an ordinary single lens to produce a square image, said Duparré.
The artificial compound eye could be ready for practical application
in five years, said Duparré.
Duparré's research colleagues were Peter Schreiber, André Matthes,
Ekatrina Pshenay-Severin, Andreas Bräuer and Andreas Tünnermann of the Fraunhofer
Institute for Applied Optics and Precision Engineering in Germany, Reinhard
Völkel and Martin Eisner of SUSS MicroOptics SA, and Toralf Scharf of the
University of Neuchâtel in Switzerland. They published the research in the
February 7, 2005 issue of Optics Express. The research was funded
by the Fraunhofer Institute.
Timeline: 5 years
TRN Categories: Optical Computing, Optoelectronics and Photonics
Story Type: News
Related Elements: Technical paper, "Microoptical telescope
compound eye," Optics Express, February 7, 2005
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