IR filters

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

Well, I have to admit that I didn't read the recent thread about using an IR
filter on a bright incandescent lamp to blind the LASER speed guns ... tried
to find something about it quickly in the hypertext archives ... no avail.

In any case I remember reading that Edmunds was listed as a former source of
large IR-pass filters, but the current offerings were too small ... well, I
just got a copy of the Edmund Scientific Industrial Optics Division 1998
Optics and Optical Instruments Catalog (N987B) and decided to give it a
look-see.  On page 62 they list "Optical Cast Plastic Windows and Filters"
which list the following features:

*	Highest Transmission and Lowest Haze of Available Transparent
Plastics (>90% for IR)
*	At least 25-50 times greater abrasion resistance than similar
plastics (Rockwell M95-M100 hardness: 97)
*	Resistant to all types of chemicals and solvents (Acetone, acids,
alkalis & alcohols)
*	Excellent thermal resistance (max operating temp 100degC continuous
- 130degC for 1 hour)
*	Easily drilled with high speed carbide bits for mounting

These filters are available in diameters up to 5.5" or 4"x5" rectangular.
P/N for the 5.5" round is F43951, with a price of $24.50, and the
rectangular one is F43954 at a cost of $11.75.  Too bad it isn't available
in the 8"x10" size they list!  The note states that the IR filters do have a
slight green color due to 1-2% transmission at 500nm.  These things sound
like they might be suited to the application at hand ... what was that spec
for the illuminator again?

HTH & IUD!
Steve Buchholz
San Jose, CA (USA)