# Future of LED phosphors



## Anders Hoveland (Apr 30, 2013)

I wrote in another thread that current LED technology still has a ways to go before it can offer us quality light for lighting our homes:
http://www.candlepowerforums.com/vb/showthread.php?359814-I-don-t-think-LED-has-a-future

The problem is that LED technology is relatively new, the vast majority of LED products presently commercially available essentially all rely on the same chip design. We are seeing LED lamps take all different shapes and forms, available in a range of "color temperatures", to try to appeal to consumers. But the plain fact is it is the light that is important, all these lamps and retrofit bulbs are are using the same type of LED chips. It is the chip that gives off the light. If you think about it, this white LED light is mostly just an orangish-yellowish phosphor with some of the blue narrow frequency allowed to leak through. It's not _really_ white light. Personally, I just find LED light to be a little unnatural looking. Ugly would probably be too strong of a word, but it just does not quite compare to the warm pleasing glow of an incandescent bulb.

But better LED concepts and better phosphors may be on their way:

http://www.open-photonics.com/featured-technologies/high-cri-leds

http://www.verbatimlighting.com/article/VxRGB-violet-chip-technology/

doped ZnS phosphors, though less efficient, may hold promise to fill in that valley in the green-blue part of the spectrum

Funny how hyped up the current LED technology was. And as soon as the technology improves, we start reading about all the terrible deficiencies of the old technology. Just a part of marketing. The big companies pushing LED retrofit bulbs for home use _knew_ their alternative lighting product had serious shortcomings, but are trying to downplay it. I also find it amusing how these companies try to selectively present information to make their product look good, and the competing option to look bad.


----------



## AnAppleSnail (Apr 30, 2013)

What terrible news! No LED has CRI over 80! I see green and blue better under LED than filament. What is the scale on that SPD, and how does it compare to an overlaid halogen for comparison. Heck, let's add the new phosphors too. Edit: Word choice: Has vs. with


----------



## TEEJ (Apr 30, 2013)

In reading your posts, you seem to have quite an agenda defending your favorite tech, and making the same (inaccurate/misleading) claims about LED's, which you plainly are against.

You exaggerate the deficiencies and ignore the positives. Come on, you are essentially claiming that no LED's have a CRI over 80? Really?

How can you hope to be taken seriously when you are so unreliable/historically biased?

Ironically, you are using the EXACT same tactics you accuse LED aficionados of...perhaps you have a dog in the fight?


----------



## evilc66 (Apr 30, 2013)

Obviously you don't try very hard when it comes to researching LEDs that actually perform. Take for example the Bridgelux Decor series.




This is only one example of a high CRI LED. There are many others from the likes of Nichia, Citizen, etc...


----------



## jtr1962 (Apr 30, 2013)

evilc66 said:


> Obviously you don't try very hard when it comes to researching LEDs that actually perform. Take for example the Bridgelux Decor series.
> 
> This is only one example of a high CRI LED. There are many others from the likes of Nichia, Citizen, etc...


And if not for that very minor valley around 480 nm, and the slight spike at 450 nm, the CRI would probably be 99 or 100 (not that anybody would be able to tell the difference anyway). Fact is many people can't tell the difference between a CRI of 80 and 95.


----------



## bshanahan14rulz (Apr 30, 2013)

I blame all the "value" LED bulbs for Anders' view on LEDs. But he should take a look at the actual LEDs available to us, and understand that these LEDs weren't made for us, so they have to be used en masse somewhere! Just a matter of paying the right price and finding the right manufacturer who has the same view on what's important in an LED retrofit. You won't find that in a brick and mortar store, the product would be too expensive compared to the other "warm white" or LED bulbs at that store.

Off topic, what is up with all the Anders Hovelands? Seems like every forum has an Anders Hoveland. Is it a common name or something?


----------



## SemiMan (Apr 30, 2013)

bshanahan14rulz said:


> I blame all the "value" LED bulbs for Anders' view on LEDs. But he should take a look at the actual LEDs available to us, and understand that these LEDs weren't made for us, so they have to be used en masse somewhere! Just a matter of paying the right price and finding the right manufacturer who has the same view on what's important in an LED retrofit. You won't find that in a brick and mortar store, the product would be too expensive compared to the other "warm white" or LED bulbs at that store.
> 
> Off topic, what is up with all the Anders Hovelands? Seems like every forum has an Anders Hoveland. Is it a common name or something?




No, there is just one Anders Hoveland that spends a lot of time posting the same stuff on as many forums across the web as possible.


Anders, you may actually garner some respect if you just stick to the facts and take your "marketing" hat off .... and when I say marketing, I mean marketing your point of view and bias.

People "blindly" go about happily under 80CRI light all the time without even thinking about it. In fact most of their life is likely spent under <=85CRI lights, i.e. almost every office and most large retail settings.

Don't get me wrong, I love high CRI, though I can't say I have a particular love for high CRI at 2700-3000K, preferring my high CRI at 4000K where it means not only color "rendering" but color gamut. 

Your post on advancements for high CRI in the mainstream is valuable and w.r.t. the violet LED, that is exactly what Soraa is doing but as shown with the Bridgelux decor, Xicato, Citizen, and LG product now, etc. high CRI is possible with blue LEDs, not only violet (which have a violet peak).


Semiman


----------



## Harold_B (Apr 30, 2013)

Just for kicks, look at the top 15-20 posts in the fixed lighting forum. You'll find Anders there in about 2/3rds of them posting one comment in a thread and disappearing. Not that I am consistently here but me thinks someone is a troll....


----------



## easilyled (Apr 30, 2013)

Presumably you (OP) think that the spectrum of an incandescent light is complete?
If so, then you are deluded.


----------



## easilyled (Apr 30, 2013)




----------



## Steve K (Apr 30, 2013)

I've learned to enjoy Anders's posts... I've realized that they shouldn't be treated as some sort of reality. Instead, I imagine them to be some sort of analog to reality TV. The characters aren't real, nor are the conflicts real. All the drama is created merely to engage the viewer and arouse emotions. It's much more fun to sit back and see what sort of antics the OP will go through just to get the audience worked up.

or.... maybe a better metaphor is professional wrestling?? But with professional wrestling, both combatants know that it is a sham.


----------



## kaichu dento (Apr 30, 2013)

Anders Hoveland said:


> Funny how hyped up the current LED technology... I also find it amusing how these companies try to selectively present information to make their product look good, and the competing option to look bad.


You're pretty funny, to talk of hype and selectively presented information, then to open a single minded defamatory thread on the future of LED phosphors.

With any honesty at all in your approach you could have easily found what it took another member to post. Together the information takes on a different tone altogether.


evilc66 said:


> Obviously you don't try very hard when it comes to researching LEDs that actually perform. Take for example the Bridgelux Decor series.
> 
> 
> 
> ...


----------



## jtr1962 (Apr 30, 2013)

Steve K said:


> I've learned to enjoy Anders's posts... I've realized that they shouldn't be treated as some sort of reality. Instead, I imagine them to be some sort of analog to reality TV. The characters aren't real, nor are the conflicts real. All the drama is created merely to engage the viewer and arouse emotions. It's much more fun to sit back and see what sort of antics the OP will go through just to get the audience worked up.


I don't know if you or anyone else here has been following the situation with bike lanes and lately bike share in NYC, but what those against these things do is very similar. They post half truths and pure nonsense in an effort to justify a point of view which really makes little sense. And then when you try to reason with them they spit more of the same back at you. Here's but a small sampling of the nonsense the daily papers here routinely spew:

http://www.nytimes.com/2013/04/28/n...w-york-neighborhoods.html?smid=tw-share&_r=2&

http://gothamist.com/2013/04/26/tales_from_the_street_citi_bike_ate.php

http://www.nypost.com/p/news/local/manhattan/what_brake_fOuhi0dco2yGKKKHLvIdyM

http://www.brooklynpaper.com/stories/36/16/dtg_defensebiking_2013_04_12_bk.html (this article is quite reasonable but some of the comments are a hoot, especially those of the guy from Pleasantville)


----------



## idleprocess (Apr 30, 2013)

Ah, it's the eagerly-awaited next installment of the Anders Hoveland show!

Let's recap:


Anders Hoveland said:


> I wrote in another thread that current LED technology still has a ways to go before it can offer us quality light for lighting our homes:
> http://www.candlepowerforums.com/vb/showthread.php?359814-I-don-t-think-LED-has-a-future



Hm, things went very poorly for Anders last episode! How's it going to turn out this time?

Oh dear, it's the same formula and the audience is responding the same as last time. This is not going to look good on the ratings...


----------



## RoGuE_StreaK (May 1, 2013)

bshanahan14rulz said:


> what is up with all the Anders Hovelands? Seems like every forum has an Anders Hoveland.


It seems to be everywhere, and always in a trolling role; I say "IT" as I'm beginning to think Anders Hovelands is a Google construct designed to infiltrate and irritate human communications networks. A precursor to Skynet?


----------



## jtr1962 (May 1, 2013)

RoGuE_StreaK said:


> It seems to be everywhere, and always in a trolling role; I say "IT" as I'm beginning to think Anders Hovelands is a Google construct designed to infiltrate and irritate human communications networks. A precursor to Skynet?


I think so also. Kind of reminds me of Smith in The Matrix:

"The best thing about being me... There are so many "me"s."


----------



## Harold_B (May 1, 2013)

Smith accumulated intelligence and power. Anders not so much. Reading his other posts I'm leaning more toward the circle-logic of Jethro Bodine. Having looked I could find only a couple threads where he engaged in an exchange of ideas (as in making more than one post in a thread) and that includes the threads he has started. He makes a post where does his "goesinta's" and doesn't look back. He does a fine job of getting under people's skins though....


----------



## easilyled (May 1, 2013)

Harold_B said:


> He does a fine job of getting under people's skins though....



Indeed, and an even finer job of doing it in a supposedly "innocent" way.


----------



## SemiMan (May 1, 2013)

Harold_B said:


> Smith accumulated intelligence and power. Anders not so much. Reading his other posts I'm leaning more toward the circle-logic of Jethro Bodine. Having looked I could find only a couple threads where he engaged in an exchange of ideas (as in making more than one post in a thread) and that includes the threads he has started. He makes a post where does his "goesinta's" and doesn't look back. He does a fine job of getting under people's skins though....




I was going to type something longer, and started, but decided against it. I had hit some point in writing where the quote about insanity and doing the same thing over and over and expecting different results came to mind ..... sad really.

Anders, we at CPF obviously like to discuss lighting and if you would like to discuss lighting, you will always find people here willing to discuss. People are much more willing to accept ideas through self discovery versus being lectured to with bias, especially when facts are being distorted and other facts being ignored. You will get a lot more acceptance by asking people how they feel about something versus telling them how they feel about something.

Semiman


----------



## Anders Hoveland (May 1, 2013)

AnAppleSnail said:


> I see green and blue better under LED than filament. What is the scale on that SPD, and how does it compare to an overlaid halogen for comparison.


This is somewhat of a complicated issue to address. It depends on the CCT of the LED. If we are comparing similar CCT, the LED light will render yellow-green colors similarly to incandescent, but blue-greens worse. LED tends to render blue colors brighter, but it depends on the color pigment and exact color. The blue spike in LED light may render different blues unevenly, or render some colors better than others. With halogen replacement bulbs now widely available, incandescent light bulbs are now available in a range of different color temperatures, from 2600 to 2960K, depending on the particular type of bulb. (a normal 100 watt 750 hour bulb seems to have a color temperature of around 2800K)

As for overlaying the spectral graph to halogen, this can be a little tricky. What amplitude should be used for each? I have seen many LED using deceptive graphs to try to make the spectrum of the LED look better in comparison to incandescent/halogen. LED has a deficiency of blue-green light in comparison to incandescent. Any graph comparison that does not show this is either using a much higher brightness/amplitude for the LED graph than the incandescent graph, or the LED graph is a higher CCT, so it is not a fair comparison.








easilyled said:


>



It is actually not as bad as it looks. Much of that red is actually far-red frequency light, which the human eye is not very sensitive to. To give a more accurate representation of the overall color, the graph perhaps should have the red shaded in a dark shade towards the right, progressively fading out to blackness. The human eye is much more sensitive to the central part of the spectrum:






So we can see why incandescent is better matched to human vision than standard LED, in terms of those reds and oranges. 

Another thing to mention is that the incandescent graph you are referring to appears to be a black body curve matched to 2700K. A standard incandescent is around 2800K, and those replacement halogen bulbs give even more coverage further into the green-blue. Here is a spectral graph of common household halogen bulbs: 
http://3dprinter.wdfiles.com/local--files/dlp-projectors-optics/tungsten-halogen-20W.gif

I did not want to have to write about incandescent light, but various forum members keep making misleading claims about how the light from standard LED is better than incandescent, when it just is not true. From an aesthetic point of view, the only reason to ever prefer standard LEDs is that incandescent halogen is not practical in a color temperature much higher than 3000K, and some people may prefer the more bluish color of light available from LED.




easilyled said:


> Presumably you (OP) think that the spectrum of an incandescent light is complete?
> If so, then you are deluded.


I will admit that incandescent gives poor color rendering in the deep blue, but other than that it is much more complete than standard LED. Of course, even with a 100 CRI, any light source with a low color temperature is going to give poor coverage of those greens and blues. You might say that incandescent bulbs are bad, but have you ever tried the *Philips AmbientLED* ? It's even worse. (it claims to be "2700 K", but I suspect the CCT is even lower than that) The green leaves of plants just look dead under it.



TEEJ said:


> You exaggerate the deficiencies and ignore the positives.


The positives? What positives? The light from LEDs is clearly inferior to incandescent. 
(yes, LED technology has other advantages, but we are just discussing the quality of light here)



TEEJ said:


> Come on, you are essentially claiming that no LED's have a CRI over 80? Really?


The vast majority of LED products on the market use standard LED light. There are a few red-enhanced products, but they are more expensive and only available in limited options, and may not be suitable for all consumers needs. And some of these higher CRI LEDs still have issues with their light, a complicated topic I would prefer not to get into here. There are a number of blue-based LED chips available with higher CRI, so it is possible, but for the most part these are not yet being incorporated into commercial lamp products. Would you prefer to have a conversation about the potential advantages of violet-based LED chips over blue-based chips achieving high CRI ?


----------



## Anders Hoveland (May 1, 2013)

jtr1962 said:


> I don't know if you or anyone else here has been following the situation with bike lanes and lately bike share in NYC, but what those against these things do is very similar. They post half truths and pure nonsense in an effort to justify a point of view which really makes little sense. And then when you try to reason with them they spit more of the same back at you. Here's but a small sampling of the nonsense the daily papers here routinely spew


You brought up a good point. Anything relating to environmentalism often seems to create controversy, with various sides selectively presenting information in a deceiving and misleading way. Personally, I think one has to seriously question anything one reads in the mainstream media or published by companies with vested interests. Even academic studies need to be taken with a grain of salt, we all know how much bias there is on _certain_ issues in academia. And then the worst part of it is government entities and private organizations perpetuating some of this one-sided information.

I suspect this may be the case (perhaps I am wrong) with LEDs. Various members may be trying to minimize the shortcomings of LED technology because of environmental/political issues. Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping the environment by converting to LED bulbs. :tinfoil:

I do not want to start another argument here, but I am just pointing out that there may potentially be other underlying reasons why various members may be supporting the positions that they are, which have nothing to do with the actual technical aspects of LED. I hope I am wrong about this.

I have tried numerous different lamps from different stores, and LED is just not ready to light _my_ home yet. I could waste more money trying even more LED products to see if there is one I like, but am not ready to do so any time soon. I will be waiting until the phosphors improve and the prices come down. Not that LED lighting is absolutely horrible, I just do not care for it. If you already have fluorescent in your kitchen, go ahead and get LED downlighting, it will be an improvement.


----------



## easilyled (May 1, 2013)

Anders Hoveland said:


> The positives? What positives? The light from LEDs is clearly inferior to incandescent.
> (yes, LED technology has other advantages, but we are just discussing the quality of light here)



I'll tell you one very big positive purely about the quality of LED light, disregarding the fact that it is far less power-hungry.

Daylight light temperature ranges from 5000K to 6500K depending on what time of day.
It is generally regarded as the ideal color temperature.

No incandescent light comes anywhere near to approaching this, and white and pale objects will always have their colors grossly distorted towards orange/red as a result of shining light of much lower color temperatures on them.

With leds like the Nichia 219, there is the best of both worlds. A high CRI (92+) in addition to a daylight color temperature. I contend that the Nichia 219, which is commonly available, will provide a much higher quality of light than any incandescent that you care to mention.


----------



## jtr1962 (May 1, 2013)

Anders Hoveland said:


> I suspect this may be the case (perhaps I am wrong) with LEDs. Various members may be trying to minimize the shortcomings of LED technology because of environmental/political issues. Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping the environment by converting to LED bulbs. :tinfoil:


You ever hear of the saying "perfect being the enemy of good enough"? Nobody here is saying LED duplicates incandescent light perfectly. When you look at the SPD it's pretty obvious the spectra are different, even for very high CRI LEDs such as the Xicato Artist series. That said, for the majority of the population they're _good enough_. Remember CFLs weren't widely accepted until their CRI got into the low 80s. After that, some people still hated them, but most accepted them. Note that the SPD of CFLs is very spiky compared to that of LEDs. If anything, screw-in LED replacements, even with similar CRI, look better than CFLs even if they may not duplicate incandescent perfectly. That gets me to the good enough part. Yes, even among those who have no problem using CFLs and LEDs, some may notice the light appears different. Not necessarily worse, just different. Eventually they get used to it because for them the advantages of longer life/greater efficiency outweigh the minor difference in appearance. It's not all about "saving the environment", either. In many cases it's more about saving money, or just not wanting to be bothering constantly changing burned out bulbs. If the downsides of LED lighting outweigh the advantages for you personally, that's fine, but don't act like there's some sort of conspiracy or agenda because the majority of the population feels the opposite. The fact is most people aren't overly fussy about light quality. If the CRI is 80 or better, it's plenty good enough.



> I did not want to have to write about incandescent light, but various forum members keep making misleading claims about how the light from standard LED is better than incandescent, when it just is not true. From an aesthetic point of view, the only reason to ever prefer standard LEDs is that incandescent halogen is not practical in a color temperature much higher than 3000K, and some people may prefer the more bluish color of light available from LED.



Nobody here ever said LED was "better" than incandescent if you're talking about light in the 2600K to 3000K range. They've often said it was nearly the same, or at least not different enough for most people to care. What lots of people have said is that incandescent is a poor yardstick to use to measure light quality by. It's heavily biased towards warmer colors, at the expense of cooler colors. Ever try to sort black and navy blue socks under incandescent light? LED, even if it's 2700K, actually gives you an advantage there. The fact is a fair number of people here feel 2700K or 3000K light, no matter the source, is lousy, and that's where LED has a huge advantage. Yes, you can make higher CCT light with fluorescent also, but the more continuous spectrum of LED means the end result looks better, even with similar CRI numbers. You seem to think the minor spectral deficiencies of LED are a major show stopper but they're not. The biggest issue is the weakness of the red end, but even here it's not a huge problem, especially with higher CCT lighting. There is less red as CCT goes up, even for a perfect blackbody, so the relative absence of deep red gets less noticeable with LEDs as CCT increases. We can already make LED lighting with CRIs in the high 90s at any CCT we want but we don't because they're niche products. I suspect that will change once LED takes over most general lighting. There will be enough demand for very high CRI LED products once fluorescent is no longer around to fill that role.


----------



## bshanahan14rulz (May 1, 2013)

As long as people will choose the cheaper of two options that they don't know about but think they have to have, "standard LEDs" will dim in comparison to quality LEDs. Everything has tradeoffs, it's up to each individual to decide what's important to them. You find that light quality trumps all other variables. I find that overall price, incl. operating costs, are pretty important. I don't think that anybody is trying to minimize the shortcomings of the LED tech to pull the wool over people's eyes; we're all here because we like LEDs, so we're all interested in the latest tweaks and enhancements. Imagine if your only experience of LEDs was a flashlight made of an array of 5mm cheap white LEDs, and that was enough to get you interested enough to look up more info. That little flashlight is amazing output for some LEDs. Until you buy a warm white LED and are blown away by the tint! Then someone comes along saying they have a high cri warm white LED. Well, I thought this plain jane warm white LED was pretty sweet, but what's this about high color rendering? Well, this continues on and on and on.

I guess my point is, yes, I agree that LEDs and the process they use to make light isn't perfect. But, if efficacy were important to me, I would have a beef with halogen and incans being not perfect either.

Anyways, here's to a brighter, more energy efficient, AND beautifully rendered future, however we manage to get there!


----------



## kaichu dento (May 1, 2013)

Anders Hoveland said:


> Funny how hyped up the current LED technology was. And as soon as the technology improves, we start reading about all the terrible deficiencies of the old technology. Just a part of marketing. The big companies pushing LED retrofit bulbs for home use _knew_ their alternative lighting product had serious shortcomings, but are trying to downplay it. I also find it amusing how these companies try to selectively present information to make their product look good, and the competing option to look bad.
> 
> Various members may be trying to minimize the shortcomings of LED technology because of environmental/political issues. Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping the environment by converting to LED bulbs. :tinfoil:


I think you work for an incandescent bulb company, since everything you accuse LED companies of doing is a mirror image of what you're doing.

There is no honesty or impartiality in your postings and your suggestion that there is something dishonest about anyone who sees advantages to LED's is really just a case of the pot calling the kettle black.


----------



## idleprocess (May 1, 2013)

Anders Hoveland said:


> I suspect this may be the case (perhaps I am wrong) with LEDs. Various members may be trying to minimize the shortcomings of LED technology because of environmental/political issues. Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping the environment by converting to LED bulbs. :tinfoil:
> 
> I do not want to start another argument here, but I am just pointing out that there may potentially be other underlying reasons why various members may be supporting the positions that they are, which have nothing to do with the actual technical aspects of LED. I hope I am wrong about this.


So conciliatory, oblivious to the tone and content of the responses to this screed of yours.

That's so funny in the face of what you normally post because swap a few words and that's _you_:



There said:


> I may be trying to maximize the shortcomings of LED technology because of quasi-scientific/political issues. I get a warm and fuzzy feeling inside, thinking I'm saving others' eyesight by discouraging the use of LED bulbs.
> 
> I'll pretend I do not want to start another argument here, but I am just pointing out that there may potentially be other underlying reasons why I may be trashing the positions that they are, which have nothing to do with the actual technical aspects of LED. I know I am not wrong about this.







Anders Hoveland said:


> I have tried numerous different lamps from different stores, and LED is just not ready to light my home yet. I could waste more money trying even more LED products to see if there is one I like, but am not ready to do so any time soon.


This, I am quite certain, is true. Since you've settled upon this point, please stop assuring yourself in public of this under the assumption that your tastes and apparently severe-yet-selective sensitivities are universal.



Stay classy, Anders.


----------



## Anders Hoveland (May 1, 2013)

easilyled said:


> I'll tell you one very big positive purely about the quality of LED light,
> Daylight light temperature ranges from 5000K to 6500K depending on what time of day.
> It is generally regarded as the ideal color temperature. No incandescent light comes anywhere near to approaching this


Ever tried using a 5500K CCT LED lamp to light your home? It looks nothing like natural daylight. Yes, the light is _bluish,_ but that is just because of the big blue narrow frequency spike. 

And then there is the “von Kries hypothesis”, which suggests that the different color receptors in the eye can change their “gain” in different environments in order to compensate for different lighting intensity levels. At lower level lighting conditions, such as those in a typical home, 2900-3500K may be the most appropriate color temperature range.




easilyled said:


> With leds like the Nichia 219, there is the best of both worlds. A high CRI (92+) in addition to a daylight color temperature. I contend that the Nichia 219, which is commonly available, will provide a much higher quality of light than any incandescent that you care to mention.


Any place I can buy a complete assembled lamp already containing this chip? How long do you think it will be before these new chips are ready to light our homes?


----------



## easilyled (May 1, 2013)

Anders Hoveland said:


> Any place I can buy a complete assembled lamp already containing this chip? How long do you think it will be before these new chips are ready to light our homes?



Well, there is a simple answer to this.

If the world was full of Anders Hovelands, these new chips would never be ready.
However if it were full of people that had experienced the quality of light of these LEDs, then they would be available almost immediately.


----------



## SemiMan (May 1, 2013)

Anders Hoveland said:


> Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping the environment by converting to LED bulbs.



And why should they not feel good ..... they ARE helping the environment by actively reducing greenhouse gas emissions. I am sure you will bark your ridiculous, unfounded and inaccurate argument about the electric heating factor of bulbs .... virtually the worse way to heat a house, but it is what it is.

Well done though Anders, judging by this thread you have gone from upsetting a select few on CPF to just about everyone. Heck even try to reach out to you and you just don't get it. At some point you have to consider that maybe you are the problem. 

Semiman


----------



## Harold_B (May 1, 2013)

Well, at least Anders is engaged more than typical. So here's one thing I find consistent in his arguments: logic is handy when applied to support his perspective but ignored when it does not (even though the argument is seperated by one paragraph).

Such as:
"It is actually not as bad as it looks. Much of that red is actually far-red frequency light, which the human eye is not very sensitive to. To give a more accurate representation of the overall color, the graph perhaps should have the red shaded in a dark shade towards the right, progressively fading out to blackness. The human eye is much more sensitive to the central part of the spectrum:So we can see why incandescent is better matched to human vision than standard LED, in terms of those reds and oranges."

All well and good regarding the red end of the spectrum but the same holds true for the blue. The eye is less sensitive to both ends of the spectrum.


----------



## kaichu dento (May 1, 2013)

Anders Hoveland said:


> Some (_insert bad word here_) people get a warm and fuzzy feeling inside, thinking they are helping...


Okay, let me try this;
Some (_Anders Hoveland_) people get a warm and fuzzy feeling inside, thinking they are helping...



idleprocess said:


> So conciliatory, oblivious to the tone and content of the responses to this screed of yours.
> 
> That's so funny in the face of what you normally post because swap a few words and that's _you_:
> 
> ...


+1
Is it really possible that he's actually that obtuse, or is it deliberate? 



easilyled said:


> Well, there is a simple answer to this.
> 
> If the world was full of Anders Hovelands, these new chips would never be ready.
> However if it were full of people that had experienced the quality of light of these LEDs, then they would be available almost immediately.


Great answer, and like so many spot on observations that it should be obvious to any but the most self-assured.


----------



## xevious (May 2, 2013)

Florescent lighting is widely used in office buildings. It is somewhat harsh cool blue-white lighting, although it does work. You can see what you're doing and get your job done without eye strain. Florescent lighting is more expensive than incandescent bulbs, but it is also 10 to 20 times more efficient. Still, at this point LEDs can produce more eye pleasing tints while still beating incandescent lights on efficiency.

LED lighting does not need to completely mimic incandescent to be workable. Generally speaking, it's stronger in some areas of the spectrum and weaker in others. Emitter tints have been getting better over time. Nichia 219 has been applauded for its color rendition. All that needs to be done is bring down the cost. And along the way, there will be other emitters that come even closer to reproducing the optimal light... which may still be various subsets of sunlight, depending upon the applications.


----------



## degarb (May 3, 2013)

Anders Hoveland said:


> I wrote in another thread that current LED technology still has a ways to go before it can offer us quality light for lighting our homes:
> http://www.candlepowerforums.com/vb/showthread.php?359814-I-don-t-think-LED-has-a-future
> 
> The problem is that LED technology is relatively new, the vast majority of LED products presently commercially available essentially all rely on the same chip design. We are seeing LED lamps take all different shapes and forms, available in a range of "color temperatures", to try to appeal to consumers. But the plain fact is it is the light that is important, all these lamps and retrofit bulbs are are using the same type of LED chips. It is the chip that gives off the light. If you think about it, this white LED light is mostly just an orangish-yellowish phosphor with some of the blue narrow frequency allowed to leak through. It's not _really_ white light. Personally, I just find LED light to be a little unnatural looking. Ugly would probably be too strong of a word, but it just does not quite compare to the warm pleasing glow of an incandescent bulb.
> ...



We get it, you do not own a good color rendering led yet. We know they exist, just that you do not believe in them. You would be more at home in the cafe or in the incan forum, rather than the led forum. 

This graph is probably about 7 years out of date. Yes, in 2008, led colors were horrid--apart from the Rebel, imho. By 2010, they conquered the color issue, the slowed lumen advance lull during this period was because they were working on color. At least this is my perception. I paint by led lights and can vouche for how long they have come since 2005 when I first awoke to their potential in my field--while I only have one 2009 warm Cree High def light which I use to help the paint store person match colors (since it shows some red better than sunlight or the store lighting). 

Then there is a huge range of leds. There is a bigger hole in your "green hole theory" than the green hole. People keep pointing you to current gen leds. I am even thinking of shouting out a group buy to get you some good leds.

The old Roman forum let all religions get up and tell their story. Even Paul preached Christianity in such a forum. I think you have, like most of us, at least something small to contribute. I like your water bottle lights post, and even have installed them in my home to my wife's chagrin. Perhaps there is a little truth in all opinions and views-else no one would hold these opinions. 

My suggestion is to post your facts first, start a new thread only if you have a new idea. Then at the bottom, put your personal tastes in quotes. Then, there is the cafe.

You led off with strong convictions and bias, and since high cri all such old news and has been manufactured for years, I am was left guessing as to the main purpose of this thread on first read. If you just posted your links, and asked if this were new news, I think this thread could have been useful. Perhaps, a thread describing the history of the LED's color rendition evolution.


----------



## degarb (May 3, 2013)

You do keep using the phrase "LED hype". This blows my old history watching mind, and many others here. Leds were around in/before 1980 (in consumer goods I knew, at least), the white invented in 97 or 99 ( I don't care which year), the high powered led in 2003, the 80 lpw in early 2007 (or was it 06-again, I dont care). Now they are running up to 100 watts and more. All while the hir incan struggles to get (I am few here that own) 38lpw (requiring 750watts).

I tend to think that nano elevators to heaven are hype. And, I agree, it is very healthy to be a cynic, to question the narative for deeper $ motives. However, Hype= no product. LED's=stuff in the stores and online.

Hype is news that never becomes a reality (probably news to bolster stock value). We are talking history here, things done, remembered and now moving on to next achievement. (How about a 200 lpw Lumiled florescent replacement tube in a year? Just because we are nerds, and are not happy with the current 100 lpw high cri Philips LPrize bulb, which is sold in Home Depot.) Saying the led is hype is like saying the microchip is all hype and will pass. This is history.


----------



## xevious (May 3, 2013)

^ I think you've done a great job of pointing out how AH has a biased agenda, rather than taking an objective POV. LED emitters are not yet perfect, but have come a long way. So I fully agree with you that what little hype was out there a few years back purporting LED's to be superior to incandescent lighting in all ways pales in comparison to the real achievements that have been made with LEDs.

Bottom line is that incandescent lights are INEFFICIENT. They throw off far more heat than useful light. It's the same thing with the internal combustion engine--it's flat out a notably inefficient mechanism that outputs tremendous amounts of valuable energy as heat. Electric motors are far more efficient. Their use still requires more research in the improvement of batteries and charging methods, but we're seeing progress made every year. And frankly, the days of tiny weak electric motors for automobiles is long gone. We've seen superior performance achieved now. It's only a matter of time before fossil fueled combustion engines are phased out due to their sorry inefficiencies. The same thing will happen with incandescent lights. It's only a matter of time...


----------



## Anders Hoveland (Aug 1, 2013)

Here is a list of some various phosphors, if anyone was wondering about their chemical composition:

496nm CaF2​:Ce3+​,Mn2+​

496nm MgWO4

496,670nm CaSr3+,Pb2+,Cl

498nm KGa11​O17​:Mn2+​

455-504nm ZnS:Cu

470nm SrMgSi2O6:Eu2+​

473nm MgWO4

475nm BaAl2S4:Eu2+​

480nm Ca3MgSi2O8:Eu2+

485nm Bi4​Ge3​O12​

486nm CaS:La3+​

492nm α-Ca3​(PO4​)2​:Eu2+​

492,500,656nm ThO2​r3+​

618nm CdS:In,Te

640nm MgSiO3:Mn2+

649nm CaS:Eu2+

660nm Mg2SiO4:Mn2+

684-732nm Srw​Fx​By​Oz​:Eu2+​,Sm2+​

685nm SrB8​O13​:Sm2+​


----------



## Anders Hoveland (Aug 1, 2013)

Harold_B said:


> All well and good regarding the red end of the spectrum but the same holds true for the blue. The eye is less sensitive to both ends of the spectrum.


 The human eye is still several times as sensitive to blue light as red frequency light. In fact, the human eye is somewhat more sensitive to the blue light from incandescent sources, because most of it is a longer wavelength than the 465nm blue frequency produced by an LED chip. I am not saying the incandescent spectrum is not a bit deficient in the blue part of the spectrum, but is not as bad as the spectral graph looks.


----------



## SemiMan (Aug 1, 2013)

This is a generic statement both accurate and wildly inaccurate depending on where you measure and hence meaningless.

Sent from my Nexus 4 using Tapatalk 4 Beta


----------



## AnAppleSnail (Aug 1, 2013)

SemiMan said:


> This is a generic statement both accurate and wildly inaccurate depending on where you measure and hence meaningless.
> 
> Sent from my Nexus 4 using Tapatalk 4 Beta



And how you measure. Most light bulb measurements scale for this sensitivity, using lumens rather than watts.


----------



## Anders Hoveland (Sep 3, 2013)

Check this out: http://starsovereden.com/EmissionSpectra.html 

If you got both some aqua and blue glow powders and mixed them, you could stimulate them with a cheap violet LED reef strip, and get a nice broadband spectrum of blue-green color wavelengths. The aqua emits around 460-530nm, while the blue emits at mostly 445-495nm. 

It would be a nice light blue color (more greenish-blue), rather than the harsh indigo wavelength from a blue LED chip. If I could create a fixture out of just this, I could combine it with a halogen bulb and I might actually have an artificial light source that could rival natural sunlight.

Or perhaps this: the latest red ZnS glow powder provides excellent coverage in the deep red (610-680nm). Just mix the blue glow powder together with ZnS red, stimulate with a separate violate chip, then mix this light behind a diffusor with regular a regular white LED.

"Photoluminescence measurements showed that the phosphor can be efficiently excited by UV–visible light from 350 to 430 nm, and exhibited bright green emission peaked at about 516 nm. Bright green LEDs were fabricated by incorporating the phosphor with an InGaN-based UV chip. All the characteristics indicated that SrAl2​O4​:Eu2+​ is a good candidate phosphor applied in white LEDs."


----------



## SemiMan (Sep 3, 2013)

You do that and tell us how it goes.

Semiman


----------



## Anders Hoveland (Jul 28, 2015)

One of the other things I think is going to eventually happen with high CRI LEDs in the future is that they are going to start to use a separate emitter to produce the deep red wavelengths, since achieving very high R9a color rendering values though better LED phosphors can substantially cut into efficiency.

Generally LED phosphor that produces deeper red wavelengths is much less efficient, for two reasons. First the human eye has a much lower sensitivity to longer red wavelengths, and second, if the phosphor emission is centered on a deep red wavelength, it is going to be producing a lot of invisible infrared wavelengths as well, due to the broad-spectrum nature of LED phosphors. Even very high CRI LED phosphor formulations will virtually always choose to use a red phosphor centered on 635nm, or sometimes 650nm. Even when centered on 635nm, the phosphor is still producing plenty of deeper red wavelengths as well. Just not quite as much as it optimally should be. Some proprietary LED phosphors have sought to overcome these efficiency problems by using quantum dots in their formulations to generate the red. There is also the Stokes shift energy loss, producing red light through fluorescence from blue light may simply just not be the optimal way to do things, in terms of efficiency.

Of course, in terms of design it is far simpler to just use a higher CRI phosphor.


If separate red wavelength emitters are used, I think the 94-95 CRI LEDs will probably utilize a 635nm supplemental wavelength, while super high 96-97CRI LEDs will use a 650nm wavelength. Much of the red wavelengths would still be produced by the phosphor, but the separate emitters would only supplement these wavelengths. Cree already uses a separate 615nm emitter in some of its high efficiency downlights, and while this does increase overall CRI over regular LED phosphor products on the market, it also results in a poor R9a [deep red color rendering] value.

Now I am probably speculating too far, but if this type of technology I am proposing here does ever become prevalent, it might start creating issues with plants, because the chlorophyll in plants is really much better suited to absorbing 660-670nm deep red wavelengths than anything much shorter. So we might see high CRI plant grow lights that combine 660nm emitters with 619nm, for color rendering and increased efficiency. (If you use a deeper red wavelength, you have to counterbalance it with something shorter and more orange-tinted for proper color rendering of skin tones)


----------

