> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Willem-Jan
> Markerink
> Sent: Thursday, November 23, 2000 5:18 PM
> To: [EMAIL PROTECTED]
> Subject: Re: EOS Diffractive Optical elements
>
<snip>
> The context of the weight- and size-advantage is also interesting:
> short lenses like this *can* be build, but the abberations would be
> massive, impossible to correct....while DO allows a decrease in length,
> without compromising optical quality....
> So it's not correct to state that DO allows a short lens as such (or
> that DO automatically means 'short') only that it allows a short lens
> without affecting image quality....and my guess is that *given* the
> choice for a short lens, a weight-advantage is inherent (but perhaps
> there would still be an weight advantage when keeping the lenght the
> same....but that would apply more to refractive Fresnel than
> diffractive grating).
Wouldn't a significant part of the weight savings come from a reduction in
the amount of glass in the lens? It seems to me that a DO lens could be
extremely thin, since the light-bending is being done by the diffraction
grating rather than by the refraction of a varying thickness of glass. In
other words, the DO element could be essentially flat, as opposed to a
conventional element that's convex, concave, or some combination thereof.
Chuck Skinner
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
