On Mon, 21 May 2001, Randy Glenn wrote:

> Has anyone heard of the CrossPad? It was a product from Cross, the pen
> company, that IBM was a major part of. It was basically a regular pad of
> paper with a radio receiver of some sort, and a radio transmitter in a
> special pen, that would digitize a good number of pages of written
> information.

You can see our version of it:

http://www.synaptics.com/technology/ips.cfm

This module can be placed behind a screen and place a resistive touch screen
(like on most PDAs). (BTW, the "clear" resistive touch screens are fairly
opaque - placing the sensing technology behind the screen dramatically improves
the contrast.)

The technical description on the web page cited is, well, vacuous. But it
essentially consists of a special RF transmitter that excites the pen, and then
listens to the signal that the pen resonates back. A custom ASIC generates the
RF signals, and processes the returned echo.

Scott

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