[rollei_list] Re: Liquid Lenses
- From: Eric Goldstein <egoldste@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Thu, 20 Jan 2005 19:33:59 -0500
John.Kot@xxxxxxxx wrote:
> Slightly OT, but have you caught up with the new variable focal-length
> liquid lenses developed by Philips? The idea goes way back, to liquid
> microscope objectives, but the new technology uses two density-matched
> fluids that distort under an applied electric field, to give a lens than
> changes focal length with applied voltage, via a process called
> "electrowetting". The target is tiny optical systems for mobile phones
> etc. Presumably the size is restricted by other forces becoming dominant
> over the electrostatic & surface tension forces that hold the small lens
> in place. There is an article in the January 2005 edition of SPIEs "OE
> Magazine" by the developers from Philips, and they also refer to their
> own paper: S Kuiper & B. Hendriks, Applied Physics Letters 85, p. 1128
> (2004).
There's quite a bit on the net on this, such as:
http://www.spectrum.ieee.org/WEBONLY/publicfeature/dec04/1204foc.html
and it is not clear that this is the property of Philips:
http://cio.co.nz/cio.nsf/0/32CF26EC42F64277CC256E5F0072E2CA?OpenDocument
Historically, the Sutton Panoramic Lens of 1859 was water-filled. With an
angular field of about +/- 60 degrees, it had no trace of coma or
astigmatism and spherical eliminated at f/30 (so says Kingslake).
Eric Goldstein
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