From: diego@minerva.st.dsi.unimi.it (Diego Montefusco)
Subject: Re: TECH: Mixed CRT and LCD HMDs
Date: Tue, 9 Feb 93 17:12:47 CET



In <9302080846.AA16982@ghost.dsi.unimi.it>, on Feb 8, you wrote:

> From: cdshaw@cs.ualberta.ca (Chris Shaw)
> Subject: Re: TECH: Mixed CRT and LCD HMDs
> Date:   Mon, 8 Feb 1993 00:05:27 -0700
> Organization: University of Alberta
> 
> You can get colour LCD's that are 720x240 resolution. Actually, this
> is a bogus number. LCD resolution numbers quote "raw" pixels. This is
> the number of individually-controllable monochrome brightness
> elements. If the LCD were black & white, this number would be
> meaningful. To get a colour LCD, you have to dye 1/3 of the dots red,
> 1/3 green and 1/3 blue, resulting in a screen that gains colour
> resolution, but loses spatial resolution.  For color LCDs, you must
> divide raw LCD resolutions by 3 in one of the dimensions, or by the
> square root of 3 in both dimensions.  Typically, LCD's do color in
> vertical stripes, so you divide the "horizontal" number by 3. Thus,
> 720x240 -> 240x240.

I don't think this is ALWAYS the case. I think some LCDs are made from
"triangles" or RGB crystals, so you don't have to divide by 3 only in
one direction. Dividing by square root of 3 (1.73) in BOTH, makes more
sense to me.

> >Here are needed HIGH DENSITY LCDs:
> >                                       SAME size (3 or 4 inches)
> >                                       N TIMES actual resolutions
> >I wouldn't know what to do with a 10,000x10,000 screen 1 meter large!
> 
> Good point. Higher density per unit area is useful, but increasing
> resolution indefinitely gives you the problem of needing an image
> generator that can output a 10Kx10K image!

Given the technology of LCD, it seems will get a 10Kx10K Image
Generator BEFORE a 1,000x1,000 hi-density LCD!!

Diego