[AG-TECH] DLP projectors and the rainbow effect

Markus Buchhorn Markus.Buchhorn at anu.edu.au
Wed Sep 18 19:34:59 CDT 2002

Hi All

As part of our evaluation of projectors for AG spaces, we had initially indicated a preference for DLP-based projectors over LCD-based ones. Now however, somebody has pointed out the DLP rainbow effect* which you don't get with LCDs.

I'd be interested to know of AG sites with DLP projectors, and how (if at all) they deal with the problem, or how they avoided it ($$$ projectors?) if they see it as a problem (some people can't see it at all, some people are really annoyed by it, some screens seem to help/hinder), any other comments? 



[*] The DLP rainbow effect is described at various sites - http://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=dlp+%22rainbow+effect%22
Basically if your eye switches focus from one side of the screen to the other, you can spot the colour transition on the colour wheel as a bright R,G,B afterimage/halo around high contrast areas. For low-contrast videoconf it's not so obvious, for visualisation applications it could be quite strong.

Markus Buchhorn, ANU Internet Futures Project,        | Ph: +61 2 61258810
Markus.Buchhorn at anu.edu.au, mail: Bldg #108 - CS&IT   |Fax: +61 2 61259805
Australian National University, Canberra 0200, Aust.  |Mobile: 0417 281429

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