Re: Fresnel Lens

[Leigh Palmer <palmer@SFU.CA>]

At 9:24 AM -0700 4/15/00, brian whatcott wrote:

> This quote reminded me of another facet of taillights (sorry for the pun).
> When visiting a maker of these things I asked how they produced the array
> of reflectors which bounce headlamp light back at oncomers.
>
> I was for some reason disappointed with the technique:
> They make up accurate metal pencils with the three mutually perpendicular
> facets worked on the ends, and stack them to make a master corner cube array.

3M makes a product called, I believe, "Diamond Grade Scotchlite".
It is a sheet plastic microprismatic version of the taillight
reflector (cube corner) device. If you haven't played with this
stuff you should do so. 3M won't tell anyone how it is made, and
I think the secrecy is necessary because the material is not
patentable. I've made some really neat things with this stuff,
and a colleague at UBC, Lorne Whitehead, has made even cleverer
ones.

Leigh