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Every few years some company/research lab will claim they have a technology that’ll simulate sunlight coming through a window, but it still isn’t something one

by GuiA 7y ago

Every few years some company/research lab will claim they have a technology that’ll simulate sunlight coming through a window, but it still isn’t something one can buy. The moment we can buy eg a 3ft by 1ft panel that we can just mount on a wall and feels like an actual sunlit window for a few thousands dollars or so, interior design is likely going to get radically different. (And that’s not to mention the sci-fi dream of a screen that can simulate a window looking out on any landscape, but these are probably way further out)

apinstein 7y ago
When we were building out an office that only had a few windows I went looking for, and found one of these. Unfortunately it’s $60k instead of $2k. According to reviewers that saw it, it’s amazing. Apparently it uses some nanoscale material that produces (mimics?) Rayleigh scattering. https://www.vox.com/2015/2/18/8060673/skylight-artificial-light https://www.vox.com/2015/2/18/8060673/skylight-artificial-li...
- BenoitEssiambre 7y ago
  I don't think the trick is the Rayleigh scattering, I think it's the parallel rays. Notice how all the pictures have well defined shadows of parallel rays?
  - raziel2701 7y ago
    I started to look into this and from a brief readings of the patents it seems that the magic sauce is Rayleigh scattering by shining an LED light onto a sandwich of two transparent panels and a solid layer of silica aerogel. I couldn't find the thickness of the aerogel layer, which will determine if you get more blue or red light out of the sandwich. It's quite ingenious, the aerogel consists of silica nanoparticles with a size distribution smaller than the wavelength of the light, leading to Rayleigh scattering to dominate. The non-uniformity of the aerogel structure is what gives it the more nuanced lighting, it lets a bit of yellow light, a bit of this and that, making a non-monochromatic source that resembles sunlight very well.
    - lahwran 7y ago
      hmm, that explains the color, but it doesn't explain the coherence. it is cool though, aerogel makes a lot of sense to use for this.
te0006 7y ago
Have a look at https://www.coelux.com/ https://www.coelux.com/. (Not affiliated, I just like the concept. But AFAIK their 'panels' still are 50+ cm thick and outside your as well as my price range.)
- leobakerhytch 7y ago
  I was hoping someone would mention this. Have you seen the product in person? I’d be very curious whether it lives up to how good it looks on video. For those unfamiliar, the panel simulates Rayleigh scattering to give the appearance of a blue sky, with a simulated sun and close to incandescent color rendering. Too bad the price tag still seems to be in the tens of thousands though.
- natmaka 7y ago
  See also https://en.wikipedia.org/wiki/Light_tube https://en.wikipedia.org/wiki/Light_tube
BenoitEssiambre 7y ago
What you want is, first, a strong source and second parallel rays (not radial rays like omnidirectional light bulbs). The later is the hard part. Because of conservation of etendue, (https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendu...) it's difficult to have very parallel rays unless the source is small and/or far away. Most spotlights still have relatively wide angles of radiation. I wonder if something like this might work if well placed: https://www.amazon.com/Primelux-8-inch-14400-Lumens-Driving/dp/B01GZST326/ref=sr_1_4?keywords=spotlight+jeep&qid=1574988540&sr=8-4 https://www.amazon.com/Primelux-8-inch-14400-Lumens-Driving/...
muti 7y ago
I remember seeing a DIY video on how to make a light panel that simulates light coming from very far away using large Fresnel lenses from old TVs https://www.youtube.com/watch?v=8JrqH2oOTK4 https://www.youtube.com/watch?v=8JrqH2oOTK4

by GuiA 7y ago

apinstein 7y ago

When we were building out an office that only had a few windows I went looking for, and found one of these. Unfortunately it’s $60k instead of $2k. According to reviewers that saw it, it’s amazing. Apparently it uses some nanoscale material that produces (mimics?) Rayleigh scattering. https://www.vox.com/2015/2/18/8060673/skylight-artificial-light https://www.vox.com/2015/2/18/8060673/skylight-artificial-li...

BenoitEssiambre 7y ago
I don't think the trick is the Rayleigh scattering, I think it's the parallel rays. Notice how all the pictures have well defined shadows of parallel rays?
- raziel2701 7y ago
  I started to look into this and from a brief readings of the patents it seems that the magic sauce is Rayleigh scattering by shining an LED light onto a sandwich of two transparent panels and a solid layer of silica aerogel. I couldn't find the thickness of the aerogel layer, which will determine if you get more blue or red light out of the sandwich. It's quite ingenious, the aerogel consists of silica nanoparticles with a size distribution smaller than the wavelength of the light, leading to Rayleigh scattering to dominate. The non-uniformity of the aerogel structure is what gives it the more nuanced lighting, it lets a bit of yellow light, a bit of this and that, making a non-monochromatic source that resembles sunlight very well.
  - lahwran 7y ago
    hmm, that explains the color, but it doesn't explain the coherence. it is cool though, aerogel makes a lot of sense to use for this.

te0006 7y ago

Have a look at https://www.coelux.com/ https://www.coelux.com/. (Not affiliated, I just like the concept. But AFAIK their 'panels' still are 50+ cm thick and outside your as well as my price range.)

leobakerhytch 7y ago
I was hoping someone would mention this. Have you seen the product in person? I’d be very curious whether it lives up to how good it looks on video. For those unfamiliar, the panel simulates Rayleigh scattering to give the appearance of a blue sky, with a simulated sun and close to incandescent color rendering. Too bad the price tag still seems to be in the tens of thousands though.
natmaka 7y ago
See also https://en.wikipedia.org/wiki/Light_tube https://en.wikipedia.org/wiki/Light_tube

BenoitEssiambre 7y ago

What you want is, first, a strong source and second parallel rays (not radial rays like omnidirectional light bulbs). The later is the hard part. Because of conservation of etendue, (https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendu...) it's difficult to have very parallel rays unless the source is small and/or far away. Most spotlights still have relatively wide angles of radiation. I wonder if something like this might work if well placed: https://www.amazon.com/Primelux-8-inch-14400-Lumens-Driving/dp/B01GZST326/ref=sr_1_4?keywords=spotlight+jeep&qid=1574988540&sr=8-4 https://www.amazon.com/Primelux-8-inch-14400-Lumens-Driving/...

muti 7y ago

I remember seeing a DIY video on how to make a light panel that simulates light coming from very far away using large Fresnel lenses from old TVs https://www.youtube.com/watch?v=8JrqH2oOTK4 https://www.youtube.com/watch?v=8JrqH2oOTK4