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Ask HN: Why are there so few artificial sunlight or artificial window products?
138 points by stevage on July 25, 2022 | hide | past | favorite | 164 comments
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?



One thing: most LEDs suck at mimicking daylight. The cheap ones are bad at delivering the full light spectrum.

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.


The trick my local bar uses is to put artificial lights behind a stained glass window. No matter what time you go in it looks like late afternoon, about an hour before sunset. Unless you have a watch or line of sight to the outer door when someone opens it, you can’t tell what time it is.

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.


Our casino takes a different approach, block all the sunlight so that no matter the time of day, the artificial light is the same.


After a very long day playing poker, I walked into the Sky Ceiling area in the Venetian and had a really strong feeling that something was very wrong. (It was probably 2 AM, but the room is convincing enough to make it feel like late afternoon and the disconnect was strong enough that I had to leave the area.)


Very true, color rendering, or god forbid flicker, are the main culprits to me.

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


>or god forbid flicker

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.


The problem just is that it's really hard to find good LEDs. Maybe they're all being sold to industrial consumers, but it's been a pain to find good LEDs if you're looking for anything more "exotic". E.g. dimmable LEDs work and are available, but there is so much cheap trash out there while good brands are often sold out. And for many sockets, there's maybe one manufacturer offering it, if at all. I've had instances where only cheap vendors offered LEDs for a certain socket.


Hmm, It'd appear you wish to retrofit LEDs in existing fixtures. That's the rub - they are not designed to work well - there is so much space for a LED driver + LEDs + cooling + looking nice. Most LEDs are overdriven to show higher lumen numbers (and watts) on the tin, which means a short life. Dimmable LEDs with a standard triac based dimmer for incandescent bulbs is a bad idea overall.

The decent LED fixtures are designed to be a single unit, e.g. near ceiling light, dimmable w/ remote/blue tooth. Unfortunately, not possible to replace parts of them, and if they are poorly built - also overdriven. OTOH, they are trivial to repair with some electronics background - often times, the driver is replaceable entirely.

LEDs need to stay cool (below 60C) to have prolonged life - say 40K hours to stay at 80% brightness. That means large heatsinks, enough space to dissipate the heat.


I've already replaced dimmers to work with LEDs. But changing all fixtures would be way too expensive, it'd then be cheaper to just stick with Halogen. And I don't need any "smart" features, an LED that can be dimmed via an external dimmer would be enough. But they're harder to find than all these "smart" devices that might stop working after a few years and can send data to who-knows-who.


>I've already replaced dimmers to work with LEDs.

While not impossible - the LED driver is a switch mode power supply, most of them would be universal one taking 90V-260V with rather variable frequency. What dimmers do - they chop the sine wave, normally that would not affect too much the driver (aside made them hot or require more bulk capacitance, which they lack) - so they have to know that the sine wave was chopped and react by reducing the duty cycle, reducing the brightness of the LEDs. That complicates the driver, however if you don't keep the LEDs at full brightness and they are not hot on touch - they should last.

The other option would be communicating through the zero cross of the sine wave, but I doubt very much it's the case.

The external dimmer is not a smart feature but more like necessity, unfortunately.


Check these out:

[1] https://www.osram.com/ecat/Professional%20LED%20lamps%20with...


God, LEDs must be the worst scam foisted upon us by governments. Flicker, lies about the lifespan, and now you say I must replace the entire lamp when it fails rather than just the bulb.


I don't think there's any malice. They're far superior when it comes to energy consumption. And they generally work well. They're just part of a general trend that it's hard to find high-quality products anymore. Unless you have industry expertise, it's extremely hard to determine which appliances are usable. Traditional DYI stores sometimes provide that expertise, buying online it's nearly impossible to search for quality.


It is malice. The government wants you to consoom while simultaneously lowering your quality of life. "Traditional [DIY] stores" are something else the govt is desperate to get rid of.


LEDs are great when done well, corporations produce flimsy garbage. As if they have some interest in things breaking apart so you have to buy new ones.


> LEDs[' dark sides]

...Interference with medical equipment (this lab I knew found out that their EEG malfunctioned when the new lamps were on...)


Poorly built drivers, yet again - no EMI suppression. Virtually any switch mode power supply that has no suppression would have done that. The LED driver in virtually all cases is some SMPS.


I know one of the tricks to detect flickering: look at the emitter through a camera, e.g. that of a phone.

How would you instead check EMI - in general? (I am not a specialist in this area.)


>I know one of the tricks to detect flickering: look at the emitter through a camera, e.g. that of a phone.

This would be a really poor driver, effectively using the AC freq. and shutting off w/ each cycle/zero cross. Unfortunately, many are exactly like that. However - some cameras do have compensation for exactly this issue, and they may hide it.

>How would you instead check EMI - in general? (I am not a specialist in this area.)

Use an AM radio. (That would depend on the frequency and what not, but AM radios are a pretty neat trick to check)


"Take an electronics testing lab with you next time you go shopping to be sure you're not getting some cheap crap"

I miss the days of a restive wire shoved into the AC circuit.


I just want LEDs that don't noticeably flicker (i'm talking 3Hz here) after a year of operation.


My bet: terrible capacitors and the driver ran hot (which caused the laps to leak out). Bad driver.

Honestly I have no clue why LED light are so poorly built nowadays. There is absolutely no technical reason for it.


There are plenty of high-CRI LEDs available at reasonable prices. Bridgelux [0] and Yuji [1] are a couple of examples off the top of my head.

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...


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.

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...


Typical LED lighting is approximately free, or close enough to zero that calculating a percentage change in cost isn't especially, ah, enlightening. The goal of the comparison is to attempt to contextualize the absolute rather than relative cost, relying on the monthly cost of air conditioning (approximately "a lot", or at least noticeable) being a more familiar value than the monthly cost of 100 light bulbs (which are individually so cheap as to vanish into noise).


The reason you'd compare it to a small air conditioner is because it's an amount of power that you can get from a branch circuit at home.

Normal indoor LED lighting is almost a rounding error on your electricity bill these days. Daylight simulation uses much more power.


But that probably emits at least 1000W in heat, so you'd then need that air conditioning, at least unless you only use it in winter.


It should be supplying closer to the full 1500W in heat, since any light it emits will just get converted to heat when it is absorbed.


But why would you compare when the goal is not to maximize your power usage before tripping a breaker. It is to get light.


Yes, the goal is to get light. And since these lights only use 1500W, you can plug them into an ordinary house electrical outlet in the US.


Yes, the goal is to get light.

Therefore a valid comparison is to measure it against other sources of light, and not air conditioners. But anyway, saying it's "only" 1500W is incredibly odd. If your goal is just to "get light" then using 115* more energy than a 13W LED bulb is completely stupid. I understand that you might want more light than one bulb gives you, but even scaling up to 10 bulbs you're still a huge margin away from a Skypanel.

If you're running an art gallery or a showroom where the quality, color, and coherence of the light makes a difference then it makes some sense. If you're at home and you just want 'some light' then it's utterly ridiculous to use that much energy.


> Therefore a valid comparison is to measure it against other sources of light, and not air conditioners.

I would definitely say that this is a false statement.

> If your goal is just to "get light" then using 115* more energy than a 13W LED bulb is completely stupid.

The goal is to get artificial sunlight. A 13W LED bulb doesn't do that. An air conditioner doesn't do that either.

However, it's nice to know how much power these lights use, so we compare them to other devices which use a similar amount of power. Air conditioners and space heaters use a similar amount of power.

> If you're running an art gallery or a showroom where the quality, color, and coherence of the light makes a difference then it makes some sense.

I don't think a SkyPanel makes sense in those applications. If you are just running an art gallery or showroom, get some ordinary high-quality lighting.


The skypanel is really really bright. The link says the 360 gets 80 lumens per watt, which is right around what LED bulbs get.


I added some Sunlike LED bulbs (the GE "sun filled" brand) to my office a few months ago. They aren't expensive, and they are nowhere near as bright as true daylight, but they do the trick.

Sunlike LED elements are available in different formats around the world:

http://www.seoulsemicon.com/en/technology/sunlike/casestudy/


If you're running 1500 watts in your office all day long you'll probably need a small air conditioner too!


not so small in the summer, too


A lot of people barely notice poor CRI lights. Heck people will mix bulbs of different color temps and not even bat an eye.

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.


'A lot of people' here being 'Many American men, in engineering / programming who are often unaware'. A lot of the women I have worked with (in dev/engineers) notice and are annoyed by this kind of mis-match. Working in Europe, also most colleagues (men and women) noticed, and made fun of, companies/ stores / restaurants that were too unaware or cheap to notice the problem or fix it.

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.


OK… I know plenty of non-engineering people who can’t tell or bother either.

And it’s not simply being aware or not. We aren’t all born with the same senses. I can spot extremely minute color variations on tests but I have never been able to tell small differences in smell no matter how much I try.


What the heck? How is gender or where you live anything to do with it?


Even ignoring the higher prevalence of colour blindness in males, it's pretty widely understood that females have better colour perception.

https://pubmed.ncbi.nlm.nih.gov/21675035/ https://www.nature.com/articles/s41599-019-0341-7


Wouldn't mixing bulbs at different colors improve the color rendering? Unless they're the same underlying substrates in different ratios (diode+phosphor), I guess, but I don't think they usually do that.


Ultimatly, what matters is how the light spectrum looks. CRI is just an attempt at reducing that to a single number. Even then, many «daylight» scenes have very different light spectra.


While daylight definitely varies, I believe the spectra for the sun at noon at sea level is reasonably even and would be the main goal (as opposed to mimicking daylight in the morning or towards the arctic).

CRI doesn’t measure vibrant red very well and human skin has that red.


Good comment, thanks. Yeah you are right. I tried to simplify this as much as possible while still providing the gist of "various white light sources can have a different coverage of the light spectrum".


One thing about CRI is reflection though. When you use an LED with a high CRI then when it illumates your furniture, objects, people etc. it will look like as if the sun shines on it (in terms of colors).

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?


High quality glass diffusors so at least the light is more indirect?


This made me think how little I actually think deeply about things.

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.


Do these lights also stimulate vitamine D production?


UVB is what's required, I believe. 290 to 315 nm.


Right, sunlight contains UVA and UVB and the UVB is what creates vitamin D. An indoor light that outputs UVB could be dangerous, the equivalent of laying outside in the sun all day, every day. It would also quickly degrade many materials in your house. UVA would trigger photosensitive eyeglasses turning them dark. Sperti makes a vitamin D lamp and it has a five minute timer and comes with UV blocking goggles (not sure what intensity it is relative to the sun) which suggests significant risk. So you may not want any forms of UV inside your home. Many windows these days have glass formulated to block UV to protect your rugs, drapes, and furniture. I'd question whether anyone would want the IR spectrum from an indoor sun-light also. I think what most people would want would be a high CRI light that has enough blue to trigger the brains time keeper. A bright indoor daylight-like light will make everything look very stark though (black shadows, objects brightly lit so you see all the fingerprints, scratches, and dust everywhere.) Your eyesight may degrade faster if you are constantly in brightly lit areas also. You may find that your autistic friends stop visiting you (or ask you to turn the lights off.) A lot of people who built A-frame houses with floor to ceiling windows at the end of the house found out that all that light entering 1) makes the house really hot 2) interferes with reading, watching TV, and using computers 3) fades their furniture and rugs. Even without the UV, bright indoor light has some issues, though it certainly can brighten dark spaces.


This seems like the sort of idea that is perhaps well-intentioned but would rub many workers the wrong way, like the Amazon mindfulness pods [0]. Employees might wonder why they can't have 15 minutes to take a paid break in actual sunlight instead of getting a dystopian fake window.

[0] - https://www.independent.co.uk/news/world/americas/amazon-men...


There are lots of good use cases. The basement storage area of my apartment complex boarded up all the small windows for maintenance / security reasons, but I use my basement as a micro-workshop. Having a fake daylight simulator window would be excellent.

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.


Well, dystopian winter (October-March) in Scandinavia has many cities with no sunlight for weeks at a time due to latitude and weather, so some really good artificial lights would definitely be welcome.


It isn't that bad. The area that is without sun for weeks is pretty small and there aren't many people living there, so trying to build a company to catch that market is suspicious at best.

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".


I don't know about Scandinavia, but even in Paris, France, there can be weeks during the winter when the sky is mostly covered, and you get next to no light.

I used to live in an apartment with huge windows, west-oriented, and no other building close by, and I still went out and bought a big ass LED light for working from home in winter. It made a huge difference to my mood.


I live in Scandinavia. I'm not from Scandinavia - I moved here in my 30s.

And trust me, even overcast days bring light. It simply isn't as bright as you desire. Lots of folks would rather have more light when it is cloudy. It definitely isn't going to compare to a month of 4-hour-long days with the sun staying low in the sky. Further south, I've seen cloudy days brighter than a sunny day in December where I*m currently living.


I live in Prague, in central Europe. During winter and autumn months the sun goes down around 16:00. People who work normal 9-to-5 hours essentially don't get any sunlight outside. Waking up in the morning in darkness sucks, leaving office in darkness sucks even more.

I'd welcome some sort of automated, artificial light source at my home office during those five months.


Warsaw is very similar to Prague but even worse.

There are 29 average sunshine hours in whole December - less than in Stockholm. That means that even if you have 8 hours of "daylight" in a day, less than one hour is when you see the sun.


I once went an entire Oct/Nov in northern Sweden seeing the sun only for maybe a couple of hours total per week because the weather was so dreary any time I was able to go outside during the day and given how short the days are in the winter.

Some days, the moon provided more light (as you say, because of snow reflection) than the sun.

Those can be some very depressing days ... weeks ... months.


Latitiude AND weather. December 2020 Stockholm had 4 hours of sun for the entire month.


2007 West Norway had an exceptional autumn, but that year I don’t remember seeing the sun between approximately September 15th and December 15th.

It might have broken through at some point when I was inside, but it was raining every single day.


That sounds so depressing. Especially in the later part of the year, the sun is weak as it is, so what is diffused through the clouds is barley enough to lift the mood.


It’s pretty bad, dude. West Norway in November; sunrise at 08:40 and sunset at 16:10. 1.2 feet of rainfall on average. 20 days of rain on average, and 20 hours of sunlight. This is far south of the Arctic Circle!

Sure, it’s not a market of millions, but that wasn’t my point. If you’re prone to seasonal depression, you’ll want a daylight lamp. Thankfully, those are available!


Winter at high latitudes can be very depressing. I've built such light fixtures for my home in the UK because it can be gray for weeks on end, without a 15-minute window of sunlight.


I looked into something like this for my bathroom, it's small with no windows, and a fake natural light source would certainly improve it


I'm a cofounder at Lumina - we're a consumer hardware startup looking to build products like this.

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!)


I've always like the idea of light pipes:

https://worldbuilding.stackexchange.com/questions/130769/can...

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


Check out https://www.parans.com/ which do just that.


That's pretty cool. It's just like Portal


An LED alternative to Microsun would be nice

https://microsunlamps.com

They are specialty metal halide bulbs - and really work!


I’m not sure where there is a large demand for natural light amongst people who both can’t get it otherwise and are in a position to do something about it.

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.


> I’m not sure where there is a large demand for natural light amongst people who both can’t get it otherwise and are in a position to do something about it.

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.


sounds like it'd be easier to make the windows. bigger than replace them with artificial sunlights. unless it's already blocked by shadow


I have an older apartment in Lisbon, I cannot make any of the windows bigger without a permit and there's no way to get a permit (I know I've tried).


Possibly but at least here in Denmark, there are lots of regulations regarding what you can do to your house, especially if it's an old one.


You obviously have no idea how expensive construction is in Melbourne.


New houses aren't much better. Windows are much larger, but triple glazing windows keep a lot of light out. A winter in Europe will be dark in nearly any home.


It seems like you don't live very far up north. In southern Sweden where I am we have less than 8h of daylight and I would love a sunlight. I've toyed with the idea of building one when I watched one of the many videos mentioned, but we live in an apartment with little room for it atm.


Yes, even in the south of the UK this is an issue. I imagine it's worse in Sweden!


Your standard multifamily unit is long and skinny with windows only on one short side (hallway on the other). Even if the window has great exposure, the light cannot penetrate far into the home unless the angle is perfect. In expensive cities even million dollar plus units are like this.


The window in my office room at home is east/north with my desk already on south wall - I need to pull down the blinders to be able to work at all in the morning just from reflection from a white wall next to the window, and as my living room is next to this room we have meh light at best in the afternoon, especially in winter.

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.


It's not just lack of windows. It gets dark at 4:30 or earlier at higher/lower lattitudes in winter, so there is demand for good lighting during the dark daytime. Those regions are often heavily overcast too.


Apparently part of the problem with convincing skylights is that the light has to be parallel to be believed.

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.


The technical term for this is collimated light. https://en.wikipedia.org/wiki/Collimated_beam

Most lights are point sources with radiating rays. But the sun is so far away it appears collimated.


Taking into account that the sun's radius is much larger than Earth's - it actually is collimated.


> satellite dish, silvered, with an LED array at the focal point

An example from DIY Perks YouTube channel [0].

[0] Building an artificial sun that looks unbelievably realistic. https://www.youtube.com/watch?v=6bqBsHSwPgw


I forgot how complicated his solution ended up being. Also he seems to have lucked out that the cone of light from his LED was compatible with the mirror. Too narrow a beam would have made the window need to be smaller.


Not to mention that the light source is a several hundred dollar very high CRI LED with exacting power requirements.

It's a cool technology feature and a beautiful experiment and short film but not exactly easily attainable to the general public.

If you make a similar system with a cheap 100 watt LED you're not going to get the same results.


Since I have enough light these days, I'll probably attack this problem from the other end.

There's a thing called a Light Shelf, in which instead of mounting top-to-bottom blinds on a window, you install a shelf a distance below the top of the window, and a blind below it. The shelf is sized and placed so that no direct light gets into the room. Instead the light passing through the window is incident on the top of the shelf, and bounces onto the ceiling. This not only creates more hours of indirect sunlight (nobody ever prioritizes cycling the blinds to optimize for daylight), it also moves more of that light into the center of the room.

I have one window that's a tough size and location for blinds, and the time of day when the light hits me in the face is pretty close to the time when a light shelf would work.


Wow, thank you for mentioning light shelves. I've had the idea without knowing about them. Now I can research better.


The hardware to create a convincing effect is simply too expensive at the moment to be mass market. You can produce collimated light with either a reflector or a lens but both have their issues. Reflectors will add required depth to the package although it can be minimized to some extent. This makes for a rather bulky install and isn't something you can just hang on the wall. Lenses allow the design to be flatter but the more easily produced fresnel variety won't have the same quality of light. You also have to balance whether to use a single point light source or multiple sources and reflectors/lenses. Cooling becomes a problem for light sources that are bright enough to mimic daylight, this would also add noise which would break the illusion of a window. You need a diffuser of some sort which adds more cost even if it is just a sheet of plastic.

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.


https://www.youtube.com/watch?v=6bqBsHSwPgw

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.


I want one, but I really want to just buy it off the shelf. A lot of other projects taking my time and attention currently.


Is it though? I find that almost every American I know closes the blinds - the exact opposite of what you're describing.


I close my blinds at home because if I don't then I get people peering in, either curiously or with malintent; I have had my apartments broken into more than once before (thankfully while I was away), presumably because someone saw valuables. Granted, this happened in those "bad neighborhoods" you're recommended to avoid when you can afford to, but still. Ain't risking it, even though I've run out of valuables.


https://www.cnn.com/travel/article/dutch-windows/index.html


Sounds lovely to me. I sure do wish I lived in a high trust society surrounded by people culturally compatible. Alas, as an American, diversity is both our strength and our weakness. Good on the Dutch though, current and historical struggles notwithstanding.


Right and when we aren’t, we are exposing the window because it’s open to ventilate for fresh air. However, I just considered many people are in high rises where privacy isn’t as serious of a concern and so you might have less window treatments in that case.


Mimicking sunlight means providing all the wavelengths, including the harmful ones like UV. Some people may not be aware that e.g. lights[1] prescribed for Seasonal Affective Disorder can actually cause burns if used for too long. They are supposed to be used for short periods only.

The FDA does not regulate light boxes, so caveat emptor.

[1] https://www.mayoclinic.org/diseases-conditions/seasonal-affe...


If we get one and it doesn't cause any noticeable burn/tan after a month of daily use, I assume we can conclude that the UV rays have been filtered out (at least to be equal or less than outdoors sunlight)?


The thing is that UV is harmful if overexposed but also harmful when there isn't exposure. Humans require a certain amount of UV to be healthy.

So I think what is needed is actually carefully dosing with full spectrum.


> The [government] does not regulate [blank], so caveat emptor.

I find this point of view so rude, tone deaf even.

"caveat emptor" only applies if you personally believe humans are entirely responsible for their own actions and can't possibly be manipulated or scammed by others. That, or you think this is likely (and it is) but you simply don't care about these people and think that this is the market correcting for "dumb consumers".

Or maybe you think the laws of the land define how we should behave to one another? Anything not made explicit by "the law" is thus meant to be ignored? Not your problem?

I'm sorry, it's just the sort of thing some one who benefits from the lack of regulation would say. It sounds biased - like you're trying to justify some venture of your own that is also "unregulated, so caveat emptor".

Let me guess, cryptocurrency enthusiast?

Anyway I say all this because there _are_ better arguments against government regulation. But caveat emptor is just saying "fuck government regulation, it doesn't let me screw people over as much". You might convince more people if your do a bit of research (and maybe don't assume everyone simply agrees with caveat emptor - this is the tone deaf bit).


You seem quite mistaken about what "caveat emptor" means ("buyer beware"). The person you're replying to means we should be cautious about using risky unregulated light boxes, which you would seem to agree with.


One thing to note is that the most important benefits of sunlight actually come from (moderate) UV exposure, which is blocked by glass and not output by LCDs as far as I know.

My own personal theory is that there is a health epidemic related to lack of sunlight exposure from most people being indoors. And so in my fantasy future cities that I build in my head, there are ways that actual natural light is delivered without being blocked by windows, such as carefully monitored full spectrum and/or UV lighting.

Another related issue is the concept of a virtual window that you can see out of. I think this will also be a future trend, since windows increase heating requirements and again don't provide the key UV component of light. Also, for the majority of history, inexpensive cameras and displays did not exist.

So what I suggest is virtual windows that are thin OLEDs and follow the person to give them a different virtualized view of outside. Or using some light field or multiview technology. Along with full spectrum lighting. And not entirely related but I think it would be best in most areas to standardize on airtight construction, mechanical ventilation and energy/heat recovery ventilators.


UIUC campus has a building that looks like a collapsible drinking cup. Each floor is a ring. Each ring is about 2 offices wider than the previous ring. The center of the building is an atrium, and the void space is approximately an inverted ziggurat.

All the inside offices have sky lights, the outside offices have windows facing out and down (due to the offices above. I’m told there are no offices without daylight in the building, but I’ve been to the basement and they must mean the above ground floors.

I’m not sure how high you can build that or how difficult it is to heat, and it has lots of light but attenuated through windows which you were against.

But I wonder if we could build a modern day Hanging Garden, where each floor has a balcony, and a series of skylights allow some light through into an atrium, or series of atriums, so those who choose to stay inside still get indirect light, and some tropical plants.


That would work great but I just feel that people should be informed that all of the UV is blocked by windows, and even though it's clear that too much UV is deadly over time, it's also clear that the tiny amounts that many people who spend almost all time indoors get is very insufficient.

But if I am reading this then maybe those atriums would provide the full spectrum light. It sounds like a really good architectural concept.


That's why I was saying Hanging Gardens, which was essentially a very large Western World ziggurat. The balconies allow for a lot of access to direct light.

If you're worried about over-exposure, I suspect you could socially engineer people by making some routes in the building as fast or faster by going out and back in.


>One thing to note is that the most important benefits of sunlight

That's taking a very narrow view of what "benefits" exist. You don't need UV for the general pleasant feeling of good light.


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427189/


  "One thing to note is that the most important benefits of sunlight actually come from (moderate) UV exposure"
How do we know this?


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427189/

A small amount of UV exposure is necessary for some processes, including Vitamin D production and a few others.

The tricky part is that it is very widely known how dangerous UV is, and people with an outdoor lifestyle can easily overdo it, but at the same time there is an increasing portion of the population that spends almost ALL time indoors (except when they are on vacation) and gets close to NO UV exposure normally.

This almost total lack of exposure to UV can be especially problematic due to high latitude, winter, or even slightly high latitude and darker skin tones.


Sure. Some people lack vitamin D. Not really the issue I'm talking about here.


My Verilux lamp comes with a warning if you are susceptible to macular degeneration. In the meantime, you can get very good high CRI lights from waveform lighting (except in CA).

A friend has the light tube in every room, I thought this was a good idea until I saw it. Everything was very cold and blueish, as if it was cloudy. I actually found it somewhat depressing.


Because it sounds like a "pod living & insect protein" product. People strongly prefer natural light to "I can't believe it's not natural light".


I dunno. I've never tried the fake version. You could predict the same to be true about Impossible Burger but that has done well.


I don't know where you are and if you can buy Yeelight. I think they have exactly what you need. https://page.yeelight.com/skylight.html I'd say roughly 400 usd.


https://www.innerscene.com


If the lack of natural light is affecting you, SAD (Seasonal Affective Disorder) lamps are easy to find.

Trying to generate sunlight that can fill a room like the sun is going to use a lot of power and generate heat. Also, the DIY youtube versions don't feel very realistic to me, it's probably a much harder (and expensive) problem to solve than just a fresnel lens.

edit: Watching another youtube video, it looks like the DIY versions are missing the "blue sky effect"


i saw one with the blue sky effect too.. i think he made essentially a narrow fish tank and then added some dish soap or something to scatter the light like the sky would


I use Vitae bulb. It has three modes - day, evening, night. See their pages for spectral power distribution: https://www.vitaelight.com/en/vitaelight-en/

You can buy it or rent it. One is for 89€ or 1.99€/month. Four are for 299€.

I use it for several years and it's great, especially the night mode.


I don't understand why you need it in 'panel' form? There's a heap of daylight and sunlight spectrum reproducing bulbs of varying qualities and price points on amazon and that are easily googlable, produced by everyone by big lighting companies (like GE) down to specialists like www.ottlite.com or sunlight2.com.


-- Kino Flo - they're really really really great - been using them for 15 years --

https://www.bhphotovideo.com/c/product/1193255-REG/kino_flo_...


The nuclear reaction at the center of our solar system, our sun, emits EM radiation of various wavelengths. FWIU, there are various devices for phototherapy (light therapy) which are more common in more non-equatorial lattitudes.

Light therapy: https://en.wikipedia.org/wiki/Light_therapy

There are various "corn bulb" LED products, but FWIU few of the products verifiably produce UVC light; and even fewer still are built from relatively new (full spectrum) UVC LEDs.

The Broan bath fans with SurfaceShield by Vyv bath fans produce ~"ultrablue" but not UVC or a detachable Chromecast Audio.

There are bulbs that switch from normal UVA to ultrablue and/or UVC on the second flIP of the circuit.


UVC causes cancer and cataracts and is blocked by the Earth's atmosphere so almost none reaches the surface. Do NOT shine UVC light on your eyes or skin!


From "Accidental Exposure to Ultraviolet-C (UVC) Germicidal Lights: A Case Report and Recommendations in Orthodontic Clinical Settings" (2021) https://journals.sagepub.com/doi/full/10.1177/03015742211013...

> While UVA radiation is the least hazardous and most associated with skin ageing, UVB is known to cause DNA damage and is a risk factor in developing sunburn, skin cancer, and cataracts. UVC is a “germicidal” radiation with the ability to penetrate deeper, killing bacteria and inactivating viruses.6 There are various types of UVC germicidal lamps—cold cathode germicidal UV lamps, hot cathode germicidal UV lamps, slimline germicidal UV lamps, high output germicidal UV lamps, UV LEDs, and UV lamp shapes with lamp connectors. The latter two are the safest to be used with the utmost precautions.

> This case report describes a vital observation of adverse effects produced by exposure to UV germicidal lamps. There are very few studies reporting accidental exposures to UVC at work in hospital settings. 7 [...]

> Importantly, overexposure to UVC radiation causes ocular and epidermal signs and symptoms. Typical skin reactions in a welder and acute sunburn produced by an electric insect-killing device with an irradiance of as much as 46 mW m-2 have been reported previously in the literature.13, 14 As for germicidal lamps, adverse effects include facial erythema, burning sensation, irritation, pain, keratoconjunctivitis, sunburn, conjunctival redness, blurry vision, photophobia, and irritation to the airway due to the generation of ozone from UVC lamps.


> The demand for "natural light" in homes and offices is very high, and higher than the availability of actual daylight.

This makes me feel as if I was entitled for wanting/wasting a scarce resource.

There’s plenty of sunlight available and it’s not running out. Let’s just make more windows.


I tried the first video, I bought a broken old tv off marketplace… guess what… the lens didn’t work and I had no use for the LEDs… so I had a broken old tv I’d ripped apart that I had to dispose of and some new LEDs I wasted money on… I guess it’s harder than they make it out to be


That sucks, but I'd definitely aim to get a broken tv for free, it's remarkably easy.


Are you looking for something like a SAD lamp (light therapy for seasonal affective disorder)? Or something like my friends have: a couple of cheap and very bright LED flat panels mounted above their dining table, in a space that has little natural light?


They aren't LED (instead specialty, high quality metal halide), but if you want a high CRI and ridiculously bright light source, Microsun is hard to beat https://microsunlamps.com I have two of them and especially in the winter I really love them. Retrofitted a floor lamp and table lamp. I don't know what kind of crazy COB LED would be required to be equivalent to them - probably wouldn't fit into standard lamps either but would require a bespoke fixture.


> So, why can't I find many such products for sale?

[1][2]

The big market for these things is hospitals. They operate 24/7, and tend to have many windowless interior rooms. Both patients and staff lose circadian rhythm in such timeless environments.

[1] https://www.coelux.com/

[2] https://www.apartmenttherapy.com/artificial-window-36758108


There is an alternative that is free, going outside more, opening the blinds, taking a break mid day. I agree there is a niche for people that live at more extreme latitudes though. Not everyone has that as a good option. I factored in the sunlight and weather when deciding where to live

It is a hard problem to solve technically. Getting collimated light in a compact space, not wasting a ton of energy while having high cri and the right color temp or emulating Rayleigh scattering. The higher end products are also pretty large.


That doesn't solve the problem of wanting to work or do other indoor activities in "natural light".


I am very interested in this myself, and I have wanted a Coelux for years.

You might also find Daniel Rybakkens work interesting:

https://www.danielrybakken.com/surface_daylight.html

http://www.danielrybakken.com/daylight_comes_sideways_files/...


Too much of a good thing? Natural light is really bright. Human eyes cope well, but our devices aren’t designed for it. It’s hard to read a screen outside.


https://www.skyfactory.com have been around for a while -- they seem more interested in the biophilia notion than the sheer intensity of light though.

Seems priced for medical settings and high-end commercial kinds of projects.


you might be interested in "You need more lumens" [0]

[0] - https://meaningness.com/sad-light-lumens


Sunlight or a sunny day are incredibly bright, so you need a fair bit of power, even with LEDs, to get close to those brightness levels beyond some small area.


Why should there be? It's very easy to get sunlight.


In some places,


You get it through clouds as well, takes a little longer. I would think the only places it may be a pain is if it's super cold or rainy all the time. Which is kind of the point of my question -- most places it's not hard, so what would the incentive be? "Go outside" is a much easier sell


https://g2voptics.com/ might interest you


What an amazing niche!


A proper window costs a lot of money to run...

Daylight is about 1000 watts per square meter, so having a 2mx2m window in 5 rooms of your house illuminated 10 hours per day with led lighting is about 200 kWh per day, which is 10x a typical Americans electric bill.

And that doesn't even include the infrared or UV that regular sunlight has, which you might want for sun tanning/warmth/realistic sun feel - including that would double the cost again.


First, it doesn't have to be as bright as sunlight, just of similar quality.

Second, you wouldn't run 5 rooms all day. Just the room you are in. And 2m X 2m is enormous.

No idea if your power figures are right.

UV would be a bug, not a feature.


You don't even need it on the 2m x 2m area. You just need it illuminating your workspace and/or your face/retinas.

Bonus points if your desk is light enough to reflect the light around you.


https://theliquidview.com/


My intuition would be that this can't be that rare: surely photographers are a lucrative market?


This isn't really a problem photographers have, if anything, photographers often have to work around natural light. A good example of this is using either fill flash or artificial shade when shooting on very sunny days. The contrast and the shadows created by full on sun are just too harsh for most situations. Similarly in a studio, you're generally not looking to recreate what sunlight looks like, because sunlight by itself often doesn't look all that good.


Why is there a shortage of daylight?


I live 53 degrees north, our shortest day is less than 8 hours.

If you work somewhere without windows (which I did for a while) and work 9-5 you basically never see the sun Monday to Friday.


Old houses or otherwise poorly designed buildings, heavily built up areas, etc.


Winter, the North. The days are short, like really short.


yes. not every one gets a lot in their home or office


I was dreaming about making a hardware startup to do just that: sun emulator window.


IKEA has fake lighted windows all over the place. I wonder where they get those.


Because Rayleigh scattering is hard (and the demand isn't there).


I believe there is a company to be built here.


Glad I live in Italy and I just need windows.


The people who put people in boxes without light don’t care about it. If they did, they’d have an office with a light!


Just say no. Add more windows.


In many built up areas that's very difficult, due to planning regulations.


Not always an option.

E.g.: https://news.ycombinator.com/item?id=32221087




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