LED lights

[dicer]

I didn't want to change the topic on my first thread.
I'm curious, about some of the LED tail lights used on some vehicles. Are there any that are laser diodes? And how bad are they for our eyes? I know there are some that cause comet trails when moving eyes rapidly side to side. Wouldn't coherent light cause that?

 

[IRstuff]

" driving like a bat out of hell backwards to warrant a really bright taillight "

The issue has never been about how bright a tail-light is in clear weather, but how bright they are in heavy rain or fog, particularly the latter, when "driving like a bat out of hell" FORWARD in fog and not seeing brake lights ahead is the problem.

Note that the Google car's usage of a laser radar doesn't necessarily solve that problem, although, the NIR wavelength of the laser radar helps a tiny bit. It's unclear how good that ladar is in poor weather. An RF-based obstacle avoidance system might be needed for freeway driving in poor weather.


TTFN
faq731-376

 

[IRstuff]

Oh, the spec range for the Google car laser

http://velodynelidar.com/lidar/hdlproducts/hdl64e.aspx

is barely long enough to handle the stopping distance for a 50 mph truck. Also, at 905 nm wavelength, the atmospheric transmission is about the same as for visible wavelengths.

TTFN
faq731-376