The demand for "natural light" in homes and offices is very high, and higher than the availability of actual daylight. And there seems to be a pretty feasible way to create a fake window (a light panel that mimics sunlight through a window), using LEDs and a fresnel lens. There's no shortage of videos around showing how to DIY such a thing, such as https://www.youtube.com/watch?v=8JrqH2oOTK4 and https://www.youtube.com/watch?v=GDeEuzKXCH4
So, why can't I find many such products for sale? There are a couple of high-end companies like https://www.coelux.com/, but where's the mass market stuff? Is there an opportunity being overlooked here, or am I just missing something?
The higher end of LED is slowly getting there. The measurement one should be looking for there is CRI ("Color Rendering Index"). The sun has a CRI of 100. Any lightsource above 90 to 95 CRI is (to my experience) indistinguishable from daylight. The best stuff there currently is are (of course) the Skypanels by ARRI for laughable 6800 USD per panel (film equipment is expensive as usual).
Blasting a 2.5 kW HMI lamp ("Hydrargyrum medium-arc iodide lamp") trough a window from the outside is a good emulation of daylight. So good in fact that the poor souls shooting films inside will have their bodies in confusion as they exit the room and realize in horror that it is dark outside.
The electrical bill of anything emulating the sun is no joke tho.
I’ve never seen behind the stained glass but am guessing they have warm light fluorescent bulbs (no heat) and something diffusing the light because it looks evenly distributed.
There are no windows on the outside of the building so it seems something you can set into a wall.
Over the last few years a ton of players have entered the film lighting space, with many offerings exceeding Arri's color rendering for far cheaper. Yuji LEDs or iFootage for example make some of the most accurate lights at 98+ cri.
The film industry will still go for Arris for other reasons, but at home we have lots of options nowadays.
Amazon listings will always claim ridiculous cri numbers, try to find a 3rd party measurement. https://indiecinemaacademy.com/complete-led-color-database-c....
https://youtu.be/qCyKdIgRVTk
That's just terrible drivers - likely an unisolated AC with a single coil. Flicker is trivial to defeat sacrificing the power factor (just add filtering caps). Overall there is nothing hard about using constant driven high-freq (over 30KHz, so no sound interference, either) LEDs.
Side note: in the days of home video calls, you can tell how many have terrible lights as the flicker is visible on the even camera.
So I don't believe it's the LEDs that are the problem.
And yes, by modern standards they can suck some juice but even a large ARRI Skypanel only draws 1500W [2], which is similar to a small air conditioner.
[0]: https://www.bridgelux.com/
[1]: https://www.yujiintl.com/
[2]: https://www.arri.com/en/lighting/led/skypanel/s360-c#F0.00S3...
Why would you compare it to an air conditioner though? Those aren't equivalents. You need to compare it to an alternative light source. A bright LED bulb uses about 13W. You could have 10 of them and still be using less than 1/10 of the energy...
Sunlike LED elements are available in different formats around the world:
http://www.seoulsemicon.com/en/technology/sunlike/casestudy/
The issue is definitely the power usage. It’s not reasonable to dedicate that much power for the relatively minimal gain.
Also, CRI is a relatively poor measurement of color quality because it measures a very desaturated color palette. You can have two high CRI lights and they will still not match. There are newer color rendering indices like TLCI, SSI and TM-30 to account for this.
Light is the prime inputs to human sensing their world! It amazes me people can be so unaware of lighting conditions / problems, when that is how they do a vast majority of these sensing of the world.
But what I would like to have is indirect light. E.g. point the lights to the ceiling and have the ceiling illumate the rest of the room. Not only is this less efficient in terms of electricty (but there isn't really a way around it) but it AFAIK also impacts the CRI depending on what material the ceiling/mat is made of.
Any insights here?
I read an OP question, and was like, meh there must be something out there.
Then I read your answer, and was like, ohhhh this makes total sense. Of course you can't have equivalent of THE SUN for $50 and consuming couple of watts per day.
[0] - https://www.independent.co.uk/news/world/americas/amazon-men...
Similarly my office has some small spaces that are perfectly sized for taking calls or having 1-on-1 meetings, but to depressing to sit in for more than an hour since there are no windows. A fake window is not a window replacement, but would make them nicer places to sit for small amounts of time.
For rest of the country the main concern is the shorter days - meaning you can easily go to work before sun comes up and leave work just as sun is going down. But during working hours there is plenty of light even if the day is cloudy since snow is very reflective.
I see the main problem with the designs OP posted that they are just LED panels mounted on a wall. You don't get the same feeling of being in the sun when the light is not directional. You might as well just have one of the "bright light lamps" on your desk that have been sold for decades to combat "sunlessness".
We've done a lot of research on lighting in pursuit of building a better webcam (our main product). We found the lights on the market (i) aren't very bright, (ii) aren't smart in any way, and (iii) are way too expensive for the functionality you're getting.
Personally, I use a 100 watt LED corn bulb but it's not very pretty.
We're considering building a light as our next product. Imagine: a light that's super bright, adapts its color and intensity to the weather / time of day / other lights in your room. (If anyone has ideas here, please reach out!)
https://worldbuilding.stackexchange.com/questions/130769/can...
https://en.wikipedia.org/wiki/Light_tube
https://microsunlamps.com
They are specialty metal halide bulbs - and really work!
Every home I’ve had (including starter apartments and a basement bedroom) was well lit by natural light. Offices have been more problematic, but decision makers generally aren’t effected by it, almost universally having window offices. Factories (at least the few I’ve been at) are often heavily lit with natural light via skylights.
That being said, there is probably a market in the higher end office design market and possibly for basements, like in the I like to make stuff video.
I think the problem then is “how do I design around/with this product.” Designers and builders roughly know how to use existing lighting products. How do you utilize this artificial sunlight product in your lighting design. Those wall mounted led windows look cool, but I’d be super annoyed if my desk were facing them. The fresnel lens looks nice in that accent position, but if it got in people’s eyes or strained them it’s a problem.
Finally, the two examples you showed are using stock led panels. As others have said, you can get some interesting effects from them, but I strongly suspect you’ll end up in the “uncanny valley” with that sort of lightning- the spectrum and consistency just isn’t quite right, the light doesn’t feel “warm” enough in the infrared, etc.
Try it out- see if you can get a lighting setup you and others love. I suspect the product is restricted to the high end currently because it’s genuinely hard to get right in a way that doesn’t feel cheap or artificial. But I’d love to be proven wrong.
Owners of old houses, particularly in inner urban areas. Lots of old houses had small windows, to keep heat in. Or have been overshadowed by taller buildings being built nearby. Or both.
Source: am one.
> think the problem then is “how do I design around/with this product.” Designers and builders roughly know how to use existing lighting products. How do you utilize this artificial sunlight product in your lighting design. Those wall mounted led windows look cool, but I’d be super annoyed if my desk were facing them. The fresnel lens looks nice in that accent position, but if it got in people’s eyes or strained them it’s a problem.
I'm imagining the market is people improving an existing room, perhaps even renters. So, designers and builders wouldn't really come into it.
So I can't really agree on it being well-lit, despite having actual windows on two sides of the apartment. Not to the point of complaining, but if only your kitchen (small, no table) and bedroom are on the west and you live in the northern hemispher... let's just say from a lighting perspective I've had 2 better apartments before this.
That’s tough to do without either reabsorbing a lot of the light you created, or creating a large box to contain the light source.
One of the interesting DIY designs I’ve seen uses a surplus satellite dish, silvered, with an LED array at the focal point. The reflected light of the mirror is mostly parallel, but your light source is now 20+ inches deep.
I spent some time instead thinking about indirect light, like an artificial clerestory. Never did build anything though. When I moved I had plenty of natural light so I stopped trying.
Most lights are point sources with radiating rays. But the sun is so far away it appears collimated.
An example from DIY Perks YouTube channel [0].
[0] Building an artificial sun that looks unbelievably realistic. https://www.youtube.com/watch?v=6bqBsHSwPgw
All of that adds up to a fairly bulky and expensive piece of equipment which is why you only see a few high end companies producing them for a very niche market.
Hopefully this can be changed in the future by having the cost of high power LEDs come down even more. Maybe mass production of high quality lenses will be helped by developments in the VR field. There are some promising developments there with so called pancake lenses that could make things a lot smaller.
If you want one, you can build one following the video above. The result is quite stunning. I've never seen anything like it.
https://www.youtube.com/watch?v=8JrqH2oOTK4
The one above is an easier build that takes up less space.