From: Leo Nikora Subject: Re: TECH: LCD yields, configurations, cost Date: 18 Nov 1995 15:57:56 GMT Organization: Virtual i-O Lots of good ideas in your last posting. Very interesting, and thought provoking. Here are a few comments about two of the easier issues you raise. Perhaps others have some thoughts on the harder questions. wilson@cs.utexas.edu (Paul Wilson) wrote: >... >I would expect that somebody would make HMD's with four LCD's, two per >eye, with only partial overlap. >... Partial overlap has two major problems. First, with the possible exception of an SGI Reality Engine, there aren't many sources (games, TV, etc.) that generate partially overlapped images. This might be solved in the future, but there's always the chicken-and-egg quandary. Second, the area of overlap always appears brigher than the rest of the image. This might be solved by complex brightness controls, but that keeps driving costs up. >... > I would think that most people would rather have hi-res LCD's >with a few dead pixels than flawless lo-res LCD's. For stereo vision, >I'd think a few dead pixels here and there would be a non-problem for >most people, as long as the flaws were staggered---you wouldn't want a >dead pixel for each eye in the same part of the field of view, >especially near the center. Randomly-placed dead pixels wouldn't be >so bad---like looking through a hi-res window with a few specks of >dirt on it. >... There are two kinds of LCD pixel defects: stuck-on, and stuck off (dead). Even a few stuck-on pixels are extreemly annoying, and destroy the emersive effect. Stuck-off pixels are less objectionable, but binocular summation seems to add them rather than cancle them. So two LCDs with 5 dead pixels each looks like one image with 10 dead pixels. This problem is exacerbated with moving images because then the stationary defective pixels seem to be in motion, and the eye notices them. Today's miniature LCDs were designed for camcorder viewfinders, and in my opinion have made a good (and perhaps the best) resolution-defect trade off. >... _______________________________________________________ Virtual i-O, 1000 Lenora Street #600, Seattle, WA 98121 website: http://www.vio.com/ e-mail: info@vio.com telephone: 800-646-3759 faxback: 206-382-0570