JoakimFlorence
Newly Enlightened
- Joined
- Jun 4, 2016
- Messages
- 194
This is a review of the Super Bright LEDs brand "high CRI" LED bulb.
60 Watt incandescent equivalent, 800 lumens, 4000K
It claims "ultra-high 95+ CRI for exceptional color rendering", and "TRIAC dimmable for smooth and adjustable brightness".
claimed efficiency: 90 lumens per Watt (or maybe only 88.8 )
The first thing I noticed is the bulb seems extremely light weight, as if it had absolutely no electronic components inside. I suspect this means it is using some sort of more direct power supply, with the AC current being directly fed into four rectifying diodes, and then directly powering a string of LEDs with the exact correct number of LEDs to match the input voltage. It's a cheaper economical design approach, but one that also results in higher efficiency.
While I can't verify this, I suspect that would mean that dimming this lamp with a TRIAC would result in some flicker, and perhaps this bulb could be vulnerable to burning out if there were a power surge.
It looks like this is using a violet based emitter. Looking through a diffraction grating, I can see what appears to be wide blue coverage, with the main color of the blue (seeming to be around 480nm in color) which is different in hue from the deeper "royal blue" than the 450-455nm seen in normal white LED spectrums. There is also a harder to see violet line, separated further away from the rest of the spectrum.
It was very difficult, but I did manage to capture pictures of the spectrum through a diffraction grating (reflecting the light off an angle using an ordinary compact disc), showing the differences between the violet emitter (left) and blue emitter (right). The light on the right is from an Ecosmart adjustable color temperature bulb set at 4000K (probably 90 CRI).
(A digital camera probably does not do the best job showing the spectrum since it selectively filters out light. You can see that yellow wavelengths do not show up very well. What the human eye sees looks different from what the camera shows in this picture, in four different significant ways)
The CRI, specifically when looking at red color rendering, seems to me to probably be somewhere between 94 to 96. It's definitely better than 90, but not quite as high as the super high 97 and 98 CRI LEDs.
The specifications say "95+ CRI (minimum), 98+ CRI (typical)".
It might indeed be 98 CRI (or approaching 98 CRI) but that is not typical of the R9 (red) color rendering. If it is "98 CRI" that would only be because of its greater coverage in the cyan and deeper blue (and violet, to a small extent) regions of the spectrum. It's definitely not the same sort of "98 CRI" that we would expect from an ultra-high CRI blue-based emitter LED. I'd say the appearance of red colors and skin tones under this light seems equivalent to what we would see from a 95.5 CRI blue-based emitter LED. (That is my perception, if I was trying to make a more exact guess and be more precise, though possible it may not be the most accurate)
The specifications say 800 lumens of light output and 9 Watts. That should work out to an 88.89 lumen per Watt efficiency, so it does seem a little strange they listed "90 lm/W" as the "Efficacy" (yes, that is how they actually spelled the word, not "Efficiency").
But even 88.89 lm/W does seem a little suspiciously high, considering this uses violet emitter based white LEDs, which typically have a lower efficiency than normal blue-based emitters. It is possible the more direct power supply could account for that (which I'd surmise by the extremely light weight).
Another possible reason for the higher efficiency is the LED phosphor does not take the "red-equivalent" CRI up to 97. (There is a very significant loss in efficiency with phosphor that provides deeper red coverage, going from 95 to 98 CRI, which is probably why it is commonly not considered very "pragmatic" to do so)
For comparison, if we look at the Ecosmart LED bulbs, that are only 80 CRI, those have specifications that list 8 Watts and 800 lumens, which would be 100 lumens per Watt. (For some unknown reason, the "True White" 3500K color temperature version seems to have a different specification of 8.8 Watts, which then works out to 90.9 lumens per Watt)
That's surprisingly not much higher than this Super Bight LEDs brand high CRI bulb.
Now to discuss the "feel" of the light, something that is important but more intangible and harder to quantify. Violet emitter LEDs tend to have a different feel from normal blue emitter LEDs. More "natural", appearing like halogen bulbs or sunlight, rather than "normal LED" light. But what I have to point out about the light from this bulb is it does not quite seem as "natural" as other high end violet emitter LED bulbs. Rather I would say the light sort of feels like somewhere in between the feel of a very high CRI (like 96-98 ) blue emitter LED and what I would expect the light from a violet emitter LED to feel like. (It does seem just a little more natural than Sylvania's "TruWave" LED light)
I do not know the reason why this is, but I could conjecture it might be that the blue phosphor being used gives a peak that is not spread out enough and is centered too much near 475-480nm, with less coverage in the 485-490nm and 450nm areas. This is quite unusual (if I'm correct about this).
Now the issue of flicker. The light feels like it might have some very low level barely perceptible flicker, which is so low level I'm almost doubting whether my perception of it is accurate. I can say the majority of people would not be able to consciously notice it, even if it was pointed out to them and they were specifically trying to notice it. I did a test with a pencil flicking back and forth, and I am still not absolutely sure that I can see signs of flicker from that. I'm guessing there might perhaps be some very small low capacity ceramic capacitor on the circuit board to help even out the wave form in the current just a little bit. (But I have not opened it up to see)
Overall, these bulbs are very affordably priced, at only $3 each, considering what they are. (The shipping costs will hurt though)
4000K also is a less common color temperature option for LED bulbs, especially when it comes to higher CRI options.
(It's a closer color temperature to how many imagine "warm sunlight" to be, not as "blue-white" as 5000K)
60 Watt incandescent equivalent, 800 lumens, 4000K
It claims "ultra-high 95+ CRI for exceptional color rendering", and "TRIAC dimmable for smooth and adjustable brightness".
claimed efficiency: 90 lumens per Watt (or maybe only 88.8 )
The first thing I noticed is the bulb seems extremely light weight, as if it had absolutely no electronic components inside. I suspect this means it is using some sort of more direct power supply, with the AC current being directly fed into four rectifying diodes, and then directly powering a string of LEDs with the exact correct number of LEDs to match the input voltage. It's a cheaper economical design approach, but one that also results in higher efficiency.
While I can't verify this, I suspect that would mean that dimming this lamp with a TRIAC would result in some flicker, and perhaps this bulb could be vulnerable to burning out if there were a power surge.
It looks like this is using a violet based emitter. Looking through a diffraction grating, I can see what appears to be wide blue coverage, with the main color of the blue (seeming to be around 480nm in color) which is different in hue from the deeper "royal blue" than the 450-455nm seen in normal white LED spectrums. There is also a harder to see violet line, separated further away from the rest of the spectrum.
It was very difficult, but I did manage to capture pictures of the spectrum through a diffraction grating (reflecting the light off an angle using an ordinary compact disc), showing the differences between the violet emitter (left) and blue emitter (right). The light on the right is from an Ecosmart adjustable color temperature bulb set at 4000K (probably 90 CRI).
(A digital camera probably does not do the best job showing the spectrum since it selectively filters out light. You can see that yellow wavelengths do not show up very well. What the human eye sees looks different from what the camera shows in this picture, in four different significant ways)
The CRI, specifically when looking at red color rendering, seems to me to probably be somewhere between 94 to 96. It's definitely better than 90, but not quite as high as the super high 97 and 98 CRI LEDs.
The specifications say "95+ CRI (minimum), 98+ CRI (typical)".
It might indeed be 98 CRI (or approaching 98 CRI) but that is not typical of the R9 (red) color rendering. If it is "98 CRI" that would only be because of its greater coverage in the cyan and deeper blue (and violet, to a small extent) regions of the spectrum. It's definitely not the same sort of "98 CRI" that we would expect from an ultra-high CRI blue-based emitter LED. I'd say the appearance of red colors and skin tones under this light seems equivalent to what we would see from a 95.5 CRI blue-based emitter LED. (That is my perception, if I was trying to make a more exact guess and be more precise, though possible it may not be the most accurate)
The specifications say 800 lumens of light output and 9 Watts. That should work out to an 88.89 lumen per Watt efficiency, so it does seem a little strange they listed "90 lm/W" as the "Efficacy" (yes, that is how they actually spelled the word, not "Efficiency").
But even 88.89 lm/W does seem a little suspiciously high, considering this uses violet emitter based white LEDs, which typically have a lower efficiency than normal blue-based emitters. It is possible the more direct power supply could account for that (which I'd surmise by the extremely light weight).
Another possible reason for the higher efficiency is the LED phosphor does not take the "red-equivalent" CRI up to 97. (There is a very significant loss in efficiency with phosphor that provides deeper red coverage, going from 95 to 98 CRI, which is probably why it is commonly not considered very "pragmatic" to do so)
For comparison, if we look at the Ecosmart LED bulbs, that are only 80 CRI, those have specifications that list 8 Watts and 800 lumens, which would be 100 lumens per Watt. (For some unknown reason, the "True White" 3500K color temperature version seems to have a different specification of 8.8 Watts, which then works out to 90.9 lumens per Watt)
That's surprisingly not much higher than this Super Bight LEDs brand high CRI bulb.
Now to discuss the "feel" of the light, something that is important but more intangible and harder to quantify. Violet emitter LEDs tend to have a different feel from normal blue emitter LEDs. More "natural", appearing like halogen bulbs or sunlight, rather than "normal LED" light. But what I have to point out about the light from this bulb is it does not quite seem as "natural" as other high end violet emitter LED bulbs. Rather I would say the light sort of feels like somewhere in between the feel of a very high CRI (like 96-98 ) blue emitter LED and what I would expect the light from a violet emitter LED to feel like. (It does seem just a little more natural than Sylvania's "TruWave" LED light)
I do not know the reason why this is, but I could conjecture it might be that the blue phosphor being used gives a peak that is not spread out enough and is centered too much near 475-480nm, with less coverage in the 485-490nm and 450nm areas. This is quite unusual (if I'm correct about this).
Now the issue of flicker. The light feels like it might have some very low level barely perceptible flicker, which is so low level I'm almost doubting whether my perception of it is accurate. I can say the majority of people would not be able to consciously notice it, even if it was pointed out to them and they were specifically trying to notice it. I did a test with a pencil flicking back and forth, and I am still not absolutely sure that I can see signs of flicker from that. I'm guessing there might perhaps be some very small low capacity ceramic capacitor on the circuit board to help even out the wave form in the current just a little bit. (But I have not opened it up to see)
Overall, these bulbs are very affordably priced, at only $3 each, considering what they are. (The shipping costs will hurt though)
4000K also is a less common color temperature option for LED bulbs, especially when it comes to higher CRI options.
(It's a closer color temperature to how many imagine "warm sunlight" to be, not as "blue-white" as 5000K)
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