[khr]

Mirrors in skylights seems like a very obvious improvement to increase the amount of natural sunlight in a space. It seems adaptable to north-facing top-floor suites. Mirrors could be installed such that the sun would reflect into the suite throughout the day. It seems to be such an obvious improvement, but I've not noticed such a system anywhere in my city. Maybe the regular cleaning of the mirrors is enough of a deterrent for building owners to invest in something like this?

[Someone]

https://en.wikipedia.org/wiki/Light_tube:

Light tube with reflective material

”Also known as a "tubular skylight" or "tubular daylighting device", this is the oldest and most widespread type of light tube used for daylighting. The concept was originally developed by the ancient Egyptians. The first commercial reflector systems were patented and marketed in the 1850s by Paul Emile Chappuis in London, utilising various forms of angled mirror designs. Chappuis Ltd's reflectors were in continuous production until the factory was destroyed in 1943. The concept was rediscovered and patented in 1986 by Solatube International of Australia. This system has been marketed for widespread residential and commercial use. Other daylighting products are on the market under various generic names, such as "SunScope", "solar pipe", "light pipe", "light tube" and "tubular skylight".”

[wefarrell]

Something like a deck prism would have a similar effect: https://en.wikipedia.org/wiki/Deck_prism

[Wistar]

Not a sunlight but Mitsubishi's new synthetic-light "windows" appear to be pretty spectacular. I want one.

https://www.bbc.com/news/av/technology-45827812/mitsubishi-w...

[r00fus]

Doesn't sound like full spectrum light. I'd live to see the CRI on those things.

[Wistar]

I did a little digging and, it appears that Mitsubishi and CoeLux have partnered on these artificial skylights and, although the CRI isn't listed, the CoeLux site says this:

"CoeLux systems combine LED lighting that reproduces sunlight spectrum, direction and brightness with optical systems and nano-structured materials that reproduce the endless distance of the sky and sun."

If it actually does reproduce the sunlight spectrum it'd have to have a very high CRI, no? Toshiba has their TRI-R LEDs claimed to be capable of 95% of the sunlight spectrum and they are rated at a CRI of Ra97. Yuji has LEDs with claimed CRI of 98, so it seems within the realm of possibility that these fake windows are very convincing.

[nine_k]

I have a few LED lamps with CRI 95, and they produce very natural-looking light, not noticeably different from sunlight. Not really expensive even.

[whitepoplar]

Wow, I want one, too!