13 Nov
2000
13 Nov
'00
5:19 a.m.
On 12 Nov 2000, Frank McConnell wrote:
"Rick Bensene" <rickb(a)bensene.com>
wrote:
Your description of the bulb mounting sounds more like the projection
type display wherein each bulb projected the image of a digit or
character onto a frosted plastic screeen at the viewed end. Each bulb
had a small lens associated with it to focus the image on the screen.
IIRC, they were typically about 1.5 x 2.0 x 4.0" and were constructed
> in some sort of Genrad whatsit that he was
getting ready to scrap.
> (He's keeping the display digits though.) Each digit is a box with a
> bunch of tiny incandescent bulbs mounted in the back; each bulb
Check out the following electronic calculator in
my
museum of old calculators:
http://www.geocities.com/oldcalculators/canon161.html
It uses this exact type of display. Pretty amazing stuff.
Thanks. Yes, that is the same sort of thing. One difference (perhaps
an improvement) in the Genrad digit-display modules is that the
grain-of-wheat bulbs are just slid into tubes in the back of the
module -- their contacts poke out the back of the module and mate up
with spring-loaded contacts in the display chassis. Also, the modules
slide out from the front of the unit, so replacing the bulbs is fairly
straightforward and can be done without soldering.
-Frank McConnell
from an aluminum extruded(?) box.
- don