2
$\begingroup$

Due to having poor distance vision and thus strong corrective lenses, I'm "blessed" with the ability to see the spectrum of a light source whenever I look at it from an angle. One thing I've particularly noticed is that blue LEDs in appliances and such seem to have two distinct blue peaks to their spectrum - that is, I see 2 offset copies of the light source's shape, both blue, but with one appearing considerably dimmer and probably close to the UV range.

All the information I can find online about blue LEDs seems to indicate I should just see a narrow spectrum around a single wavelength somewhere around 460-480 nm. Are these perhaps just white phosphor-based LEDs behind a blue filter that's transmitting both the original blue and part of the spectrum of the yellow phosphor? Or is something else going on?

$\endgroup$
1
$\begingroup$

The second image is probably the same colour, but due to internal reflection of the lens (off the near face and back off the far face). I'm sorry to say that your blessing (which I share, btw) is not limited to chromatic abberation.

$\endgroup$
  • $\begingroup$ An internal reflection in my lenses (glasses) as opposed to at the light source? Why would it only happen for certain sources of blue light? $\endgroup$ – R.. GitHub STOP HELPING ICE Sep 7 '17 at 2:39
  • $\begingroup$ It wouldn't, but as the reflection co-efficient is usually pretty low, 1%, it would only be noticably visible for very strong light sources (ideally with well defined boundaries). $\endgroup$ – JMLCarter Sep 7 '17 at 2:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.