Archived posting to the Leica Users Group, 2001/03/28

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Subject: [Leica] Chips
From: Stephen Patriquen <patriquen@yahoo.com>
Date: Wed, 28 Mar 2001 03:58:29 -0800 (PST)

I've spoken to a friend in the industry and he has
confirmed that CCDs are now made the same way as other
chips, in predetermined die sizes on wafers that are
then cut up and wire-bonded, etc.

Of course, the market demands this as digital cameras,
etc. have to be designed to use specific size chips.

I've also determined that there are very large CCDs
available - at least up to full-frame 35 size
(24X36mm). (Still too expensive to be common, though).

There is an inherent difference between CCDs and most
other chips in that the CCDs are essentially all the
same element repeated across the surface (pixels
formed from tiny light-sensitive capacitors) and not a
complete multi-layer electronic unit formed of
transistors, diodes, etc, to perform some specific
function. In some ways, they are "digital film" in
that bigger is better (and more expensive).

Although I have no proof or any way to prove it, it's
possible that my discussion with Kodak ten years ago
(about huge CCDs) was in the context of batch
production techniques (where at least theoretically
such CCDs are possible) and not mass production. I
didn't know any better at the time to ask for
clarification.

Steve Patriquen
London

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