Date   : Thu, 04 Nov 2010 12:14:46 +0000
From   : list-a_cloud9.bbc-micro@... (Theo Markettos)
Subject: Acorn's US patent

In article <20101104112517.avwht9ff40cg8048@...> you wrote:
> Rick Murray wrote:
> > The other patent is:
> >    http://www.freepatentsonline.com/5400044.pdf
> > which describes a method of taking a one bpp LCD display (pixel on or
> > pixel off) and modulating pixels around plus refresh speeds, to make a
> > pseudo-greyscale display device out of it.
> 
> Isn't that how the A4 display worked?

Yes, that's what's implemented in the A4's LCD ASIC.  The A4 TRM mentions
that it's patented, but I hadn't seen the patent before.

The A4's display is actually two completely separate panels (top half and
bottom half) with no gap between them, so the ASIC has to raster scan both
halves at once.

Theo