Tim
The attacking pilot will *hope* to have large differences for the
missile to play with, but he will also hope that the performance
envelope is a wide one which will allow him superior attacking
performance. That is, he may not have the best temp differential to
play with when the target is close to the sun or "hot" clouds
reflecting the sunlight etc... Hence, the uncooled head was good for
a rear hemisphere shot at close range (say 1000 yards) while the
latest cooled heads will detect a head on aircraft (probably in
afterburner) at over 8 nautical miles and can reject flares and cloud
lines.
But back to IR film: do we agree that it is temperature difference,
manifested as a difference in radiation wavelengths, that gives IR
film (or the near-IR consumer films) their distinctive sensitivity?
..... or am I still way off the mark?
Chris
Somebody asked about heat seeking missiles and these have huge temperature
differences to work with (1000's C) but need much fast responding sensors,
the consumer thermopiles are pretty slow. The earliest ear thermometers used
pyroelectric sensors and a mechanical chopping scheme. Some newer mems based
sensors (micro bolometers etc) are just becoming available which may be used
in these consumer IR applications in future.
Regards,
Tim Hughes
>>Hi100@xxxxxxx<<
--
<|_:-)_|>
Chris Barker
imagopus@xxxxxxxxxxxxxxxx
... a nascent photo library.
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