P3D Fluorescent Lamps

[vidi@xxxxxxxxxxxxx]

Bill Stickley wrote about the possibility of using a fluorescent lamp in a 
viewer.  I have a lot of information at work (which has also been posted 
here before, Archives?) regarding sources for small fluorescent lamps and 
lamp driver devices.  There are off-the-shelf lamps which are from 3 to 6mm 
in diameter and only a few inches long which I think could work well in a 
stereo viewer.  I have personally tested a 5" lamp and Inverter powered 
from 4 AA batteries for 9 hours of continuos operation.  The test was 
stopped after 9 hours because I defined "end of life" as the point where 
the light fell 50% from its original value with fresh batteries.  If these 
same components were applied in normal, intermittent use, they would 
probably last for many many months before a battery change was required.

   Another benefit of using the fluorescent lamp/inverter combination is 
that the inverter is designed for constant current operation.  In this case, 
the inverter continuously applies a fixed current to the lamp producing a 
fixed light output regardless of battery consumption (until there's no power 
in the battery of course).  This made for a constant light out of the lamp 
until the last hour or so of operation, at which time I measured the intensity 
decreasing until I hit the 50% point.  As you know the lamps run much cooler 
that a halogen, they produce a distributed source (not a point source which 
needs complicated diffusing), they have an average life of some 20,000 hours,
and you have your choice of colors (or color temperature).  There is no way 
anyone , not even Dr. T, could dispute the benefits of fluorescent illumination 
in a viewer over an incandescent source.  I'm really surprised they're not 
used more often.  There is a lot of false (or misleading) information spread 
around on these posts regarding these lamps but I'd like to make sure that 
those who want to know and learn about this technology do so with the correct
information.

   If you post specific requests for information (spectral curves, vendor 
contact info., prices, etc.) before I go back to work on Monday, I can have 
the details back here Monday night.  I'd like nothing better than to hear 
someone has converted a Realist Red Button to fluorescent illumination and 
it knocked their socks off when they viewed their first stereo slide!


Respectfully submitted,

John Vala



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