vic@grep.co.uk (Victor Gavin) (03/21/91)
Hi, can anyone point me in the direction of a LCD (or similar device) which has a high efficiency for the transmission of light when it is ``transparent'' but nearly nothing when it is ``opaque''. From what I've been able to find out, 5% is about the norm when the unit is transparent (due to polarisation etc.), whereas I'm looking for something in the region of 30-50% (or better if possible). Has anyone any suggestions ?? vic -- Victor Gavin <vic@grep.co.uk||..!ukc!grep!vic||..!ukc!vision!grep!vic> Grep Limited, Kirkfields Business Centre, Kirk Lane, Leeds, UK, LS19 7LX
don@zl2tnm.gp.co.nz (Don Stokes) (03/26/91)
vic@grep.co.uk (Victor Gavin) writes: > Hi, can anyone point me in the direction of a LCD (or similar device) > which has a high efficiency for the transmission of light when it is > ``transparent'' but nearly nothing when it is ``opaque''. > > From what I've been able to find out, 5% is about the norm when the > unit is transparent (due to polarisation etc.), whereas I'm looking > for something in the region of 30-50% (or better if possible). Well, LCDs rely on polarisation to do their stuff. The only real area for improvement is the transparency of the LCs and polarising filter. The polarisation is unavoidable. Don Stokes, ZL2TNM / / don@zl2tnm.gp.co.nz (home) Systems Programmer /GP/ GP PRINT LIMITED Wellington, don@gp.co.nz (work) __________________/ / ---------------- New_Zealand__________________________
erk@americ.UUCP (Erick Parsons) (03/29/91)
>>vic@grep.co.uk (Victor Gavin) writes: >> Hi, can anyone point me in the direction of a LCD (or similar device) >> which has a high efficiency for the transmission of light when it is >> ``transparent'' but nearly nothing when it is ``opaque''. >> >> From what I've been able to find out, 5% is about the norm when the >> unit is transparent (due to polarisation etc.), whereas I'm looking >> for something in the region of 30-50% (or better if possible). Hmm... Where I work, we experimented with some really neat signs that showed only a portion of a highway sign at certain times of the day. Being dictated by a 120 VAC Solid State switch hooked up to a timer. The unit was a (supposedly) weather tight metal frame about 8 inches deep and the same WxH as a standard highway sign. The sign was mounted to the back of the frame, a plexiglass window with a mylar looking sheeting pasted to the back went in front. The sheeting was CLEAR when not energized. When exited with 120 VAC directly to this sheeting material the sheeting would immediatly go opaque obstructing view to the sign behind it COMPLETELY ! As I recall there was no x-former or ballast of any kind mounted inside but to this I would not swear as it's been a while since I've looked at the documentation. If there is interest I will dig up the documentation on it and post what I find.. Mfg. name(s) number(s) etc. Really neat stuff. -- Erick Parsons, Sacramento erick@sactoh0.sac.ca.us <-- Right off the freeway -- {ames att sun }!pacbell!sactoh0!pacengr!americ!erk <-- At the end of the road --