isw wrote in message
]...
In article ,
"N_Cook" wrote:

I picked up some these curiosities in a car boot sale, no known history.
Anyone have any info , particularly date.

They are made of 2 sandwiched very thick 1/8 inch glass slabs with
obvious
epoxied over liquid filler-holes, otherwise size etc is much the same as
modern, standard sloping 7 segment displays, conductive lands and traces
etc. These ones 3 1/2 digit and annunciators for DVM. No built in
polarizers. The segments go cloudy white on 40 to 60V ac drive, the same
between added polarizers. Wrapped in tissue paper, then expanded
polystyrene
and original cardboard wrapping , new unused, made by Hamlin Inc, type
number 3601-0

I have seen early LCDs that behaved just like that. The "cloudy white"
you describe is how the display is used in practice; there would be some
sort of edge light to enhance the effect, but the display sort of stuck
out the top of the box (in this case it was a calculator) and you could
see right through it. As I recall, it also was very slow (by today's
standards) in switching between "on" and "off".

Isaac


There were, with them, what I thought were more recent so left unlooked-at ,
wrapped watch displays. But some dates in there for the 3302 type , were
1973 and 1974. I cannot get any sign of life on any of them, up to 60 volts
ac. No staining in the tissue paper of leaked liquid, surely not 100 volts
or so? Distinctive gold evaporation semi-transparent coating on one side of
them and similar obvious stopped filler/vent holes. Must be contemporaneous
as both 3601 and 3302 along with 8 digit 3501 and clock display type 3401
shown on the packaging.