Where to buy polarising lense to invert clock LCDs?

[Mr.Tom]

I saw a tut once, but can't find it now. I wanted to invert the LCD displays on the dash, so that the numbers light up, and the surround it black. Seen it done, but can't find a source for the polarising plastic sheet. Has anyone got a source, or a spare bit I can snag?
Cheers.

[Thom89]

Try RS components
http://uk.rs-online.com/web/generalDisplay.html?id=RSbrand%2Fownbrand&cm_mmc=UK-PPC-_-google-_-0_RS%20Brand-_-rs%20components_Phrase

Thinking about it, don't you just turn the glass filter over?
Thom

[Mr.Tom]

I thought it would have to be rotated 90 degrees to swap the polarisation. Thanks for the link tho (£15 for a sheet :s )