Huie
Member
Registered: Nov 1999
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Posts: 10 |
My assumption on Lexan LCDs is this- LCDs are made of glass because the Liquid Crystals are placed between the two glass layers and that gap should be pretty precise. They use micro-spheres as spacers to keep the two glass layers apart. I would assume that glass is nice and hard and so keeps a pretty precise gap. Plastics would probably deform around the micro spheres and give a pretty poor separation. This would result in splotchy images- sort of like when you touch the LCD screen of a laptop (which I'm sure no one would like, given everybody's whining about image streaking).
Yes, the glass also has a conductor sputtered on the surface for pixel address, but that same thing can be done on plastics- the digitizer has a flexible layer of polyester that also has a conductor sputtered onto it (as does the glass backing of the digitizer).
Admitedly, the digitizer could be mounted to a layer of Lexan, but then it would need two layers of polyester (like the original Pilot 1000, I believe). This would have been nice since last month I dropped my Visor and broke the glass on the digitizer, but not the LCD- I ended up cannibalizing the digitizer off a PPPersonal but needed to do a bit of jumpering inside the Visor to compensate for the different pinouts of the two digitizers.
Thinking about it again- making a digitizer with a plastic backing and two polyester layers is a QA nightmare because trying to adhere a polyester layer to the plastic backing would result in some amount of rejects with bubbles and other deformations in the polyester or adhesive.
Maybe the conductor could be sputtered onto the plastic backing, but then there might be signal routing and manufacturability issues that I'm unaware of.
-mark
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