|Re: polarization... or Take Me Out to the Ball Game|
Message #5 Posted by Paul Brogger on 20 June 2006, 12:14 p.m.,
in response to message #3 by Jonathan Eisch
I once experimented with a Sharp "landscape" (or "slide-rule") format scientific. Taking it apart, I noticed that there were no electronics behind the LCD. I thought it would be a cool back-lighting effect if I cut a window in the back case, and removed the reflective sticker on the back of the LCD glass, thus letting light in from behind.
Well, imagine my shock when, upon removing the back sticker, the LCD image completely disappeared! I had created a blind, empty, glass window in place of the calculator's display.
Somehow, I stumbled across the fact that the plastic cover was polarizing the light passing through. I dug into my calculator "bone box" and found another plastic window from an old LCD four-banger. I found that if I put the second window behind the LCD, my display was restored. Furthermore, if I flipped one or both of the plastic covers (I don't remmeber the details), I could reverse the display's polarity -- with "clear" segments swimming in a black background.
This was all cool, but my back-lighting experiment actually made the calculator more difficult to use. I had to hold it off the table to let some reflected light pass in from behind -- I couldn't simply set the thing down and use it.
Eventually, I sat down at the coffee shop with the thing in my back pocket, and cracked the LCD. Bummer! But it had been fun to experiment with . . .