Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Apply directly to forehead.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                                   

pseudo or all light laser

reflect, and channel ordinary light into block of tight parallel beams
  (+2, -1)
(+2, -1)
  [vote for,
against]

After playing around with trying to get an ordinary bulb to shine a reference grid, I realised a) the bulb was no where near powerful enough and b) it was diffuse, causing the blurring of bulb reference mask.

What if the bulb was placed in a parabolic reflective container the only way out is an area that all the reflections have to be parallel to each other. Any rays not exiting are reflected to have another go at the parabolic mirror, if not reduced to heat. This of course, is what happens at any torch head, except the bulb is usually in the way and only half the generated light reflected through the mirror.

To do this properly, the bulb has to be offset and out of the way of the direct line of the parabolic exit. Think a reverse mirror telescope with bulb at the eyepiece.

The thing is, there would still be rays slightly off the perfect parallelism so what if there was a block of optic fibres all perfectly parallel, sandwhiched together over the exit. These optgic fibres would be different though, the inner surface would not be about reflection but absorption. The optic fibre sandwhich would only let though the rays that are parallel to direction needed.

Summing up, a bulb enclosure to only let light of multi frequencies, hence pseudo laser, in parallel lines for cheap experimentation at home. The stronger the source the better.

Did I say the beam was wide.

wjt, Jun 13 2021

Collimated Beam https://en.wikipedi...iki/Collimated_beam
[a1, Jun 13 2021]

[link]






       collimated light =/= coherent light.   

       also, optical throughput is (solid angle)*(area) so as the beam gets better collimated the amount of light going through it gets less.   

       good effort but there are some science issues...
sninctown, Jun 13 2021
  

       True, the width is only going to be big as the torch or optic fibre block, but compared to a laser's window, for home use, free and portable.   

       The proof will be in the percentage loss between the photons generated and those that manage to be reflected in the case, straight out the optic fibres. Hopefully no solid angle at all.   

       The masks or shadow puppetry should be sharp-ish at a range of distances.
wjt, Jun 13 2021
  

       I think the sandwhiching is the key technology that needs to be explained.   

       When light comes out of a single optical fibre, it is not in the form of a collimated beam, it diverges and spreads from the end of the fiber. So unless the sandwhich runs from the lamp exit all the way to the target it won't do very much.   

       Or you could just have an infinitely bright point light source an infinite distance away, that would work pretty well I think and has the advantage of great simplicity.
pocmloc, Jun 13 2021
  

       another issue is that the optic fiber block (grid of small circular openings) won't work as expected because of diffraction...each small opening will cause the beam to diffract/diverge outward.
sninctown, Jun 13 2021
  

       // an infinitely bright point light source an infinite distance away would work … //   

       Except an earthbound wjt might only have it in line for an instant once or twice a year. A properly placed solar orbiter *might* be able to hold station in the beam for a while, but this is no longer suitable for cheap experimentation at home.
a1, Jun 13 2021
  

       1: You can get pretty tiny LEDs these days; use as a "point source" with a parabolic mirror, et voila!
2: Why not just use a laser?
neutrinos_shadow, Jun 13 2021
  

       These optical fibers are special, with an internal absorbing coating. Only photons travelling the length of the fibre get through, almost parallel.   

       1 the led and supply lines are in field but yes, the optical fibres will be an attempt at a grid of point sources.   

       2 I did think of a defraction grating but again either a small area, one laser or changing distant between dots if lensed stack of lasers and defraction crystals? don't know.   

       what I was trying to realise was a standard flatish light bulb that put out a light grid that didn't change relative to the distance away.
wjt, Jun 19 2021
  

       // special //   

       You mean magic?   

       // a light grid that didn't change relative to the distance away.//   

       Even the best lasers display some beam spread, because current technology does not reach the theoretical perfection of 100% coherent light. And a non coherent beam will inherently spread.   

       // with an internal absorbing coating. Only photons travelling the length of the fibre get through, almost parallel. //   

       What angle of incidence will count as NOT parallel? Absorbed photons are wasted energy, and that could be a lot of wasted energy. Every photon’s special, every photon’s great. If a photon’s wasted, God gets quite irate.
a1, Jun 19 2021
  

       Increasing entropy is never a waste! It's the true purpose of the universe and everything in it, after all.
pocmloc, Jun 19 2021
  

       [pocmloc], I dispute your assertion about the purpose of the Universe - or even that it has one - as it would imply a conscious intent outside of the Universe itself. There may be one beyond our understanding but I wouldn’t accept it on faith.
a1, Jun 19 2021
  

       There can be purpose without consciousness
pocmloc, Jun 19 2021
  

       Only with your own definitions, different from mine. Purpose implies intent which implies consciousness.
a1, Jun 19 2021
  

       Maybe
pocmloc, Jun 19 2021
  

       No maybe about it, your definitions are different from mine. I think…
a1, Jun 19 2021
  

       What you're describing is a standard bulb-in-a-box microscopy light source, nothing new with that. Add on a collimator & liquid light guide and that's the rig I have in the next room.   

       //collimated light =/= coherent light// Exactly, coherent light isn't needed anywhere as often as people think. Lasers are used mostly because they're good at supplying an awful lot of light a specific wavelength, you don't need coherence for cutting steel for example.
bs0u0155, Jun 21 2021
  

       The problem is the area needed. To coat the probable play paths of a table tennis ball over a table, with the light source above , needs multiple wide collimated sources.   

       The masked, collimated light's shaddow pattern has to interact with the pattern on the ball.
wjt, Jul 03 2021
  
      
[annotate]
  


 

back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle