Cree XP-L High Intensity LED
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markr6
Flashaholic
- Joined
- Jul 16, 2012
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It drives me insane that there are several nice tints, two here (5750-6000 and 5700-6100K) but manufacturers always use the blue ones!
2xTrinity
Flashlight Enthusiast
Sorry in advance for the mild thread necromancy:
I take their ststement to mean higher output for entire optical systems or luminaires that use the XP-G2 chip. Since the XP-L HI chip has higher surface brightness it may end up with more total throughput through the secondary optics. That statement implies that the distance between the mounting surface and the apparent location of the die image is the the same for both the XP-G2 and the XL-L HI, so that the parts could be substituted without needing to reposition any secondary optics.
I can't confirm if that's actaully true.
Yes. the main reason flat LEDs like this are advantageous is that they have high surface brightness (or radiance).
LED domes improve overall efficiency and lumen by allowing rays that would otherwise totally internally reflect to escape, but the consequence is they magnify the apparent size of the die by 1.5X, meaning an apparent area of the die by 1.5^2, or 2.25. (it's actually even worse when you consider the image of teh die is distorted when viewed at large angle).
The lack of a dome also means you can place optics such as aspheric lenses much closer. With a dome you are limited to optics that have a long enough working distance (distance from the back surface of teh lens to the apparent location of the LED die) to clear the thickness of the dome.
It also means that components such as light pipes or homogenizing rods can be placed in flush contact with the LED. A domed LED cannot be easily used with devices like tapered light pipe rods without excessive losses. A combination of a domeless LED, a tapered light pipe, and an aspheric lens can basically be used to form an extremely uniform and high intensity light source suitable for microscope illumination. That's a lot harder to pull off with domed LEDs.
I take their ststement to mean higher output for entire optical systems or luminaires that use the XP-G2 chip. Since the XP-L HI chip has higher surface brightness it may end up with more total throughput through the secondary optics. That statement implies that the distance between the mounting surface and the apparent location of the die image is the the same for both the XP-G2 and the XL-L HI, so that the parts could be substituted without needing to reposition any secondary optics.
I can't confirm if that's actaully true.
Yes. the main reason flat LEDs like this are advantageous is that they have high surface brightness (or radiance).
LED domes improve overall efficiency and lumen by allowing rays that would otherwise totally internally reflect to escape, but the consequence is they magnify the apparent size of the die by 1.5X, meaning an apparent area of the die by 1.5^2, or 2.25. (it's actually even worse when you consider the image of teh die is distorted when viewed at large angle).
The lack of a dome also means you can place optics such as aspheric lenses much closer. With a dome you are limited to optics that have a long enough working distance (distance from the back surface of teh lens to the apparent location of the LED die) to clear the thickness of the dome.
It also means that components such as light pipes or homogenizing rods can be placed in flush contact with the LED. A domed LED cannot be easily used with devices like tapered light pipe rods without excessive losses. A combination of a domeless LED, a tapered light pipe, and an aspheric lens can basically be used to form an extremely uniform and high intensity light source suitable for microscope illumination. That's a lot harder to pull off with domed LEDs.
throwerloverX
Newly Enlightened
- Joined
- Dec 24, 2015
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Does high CRI XP-L HI exist? I noticed some 80+CRI warm XP-L but not the HI version (?) some dedome can reach the XP-L HI output but the tint result is a real lottery... Any ideas? tks
Will the XP-L HI take 3.3v at 3a? From what I could gather that would be over driving the LED some but I'm not sure how it'll take it since Cree doesn't list it beyond 2.95v at 3a, I know the XM-L2 can take being over driven somewhat. I've got a custom made light with 3 XM-L's driven at 3.3v 3a and one is gone dim and shifted colder than the rest, I was just going to drop in some XM-L2's but with the shape of the reflector I'm thinking a XP-L HI would throw better than an XM-L2. I have a Nitecore EC4GT with a narrow but deep reflector and a XP-L HI V3 and it's got lots of throw and a very tight beam, the custom light has narrow but deep reflectors too but they're much smaller over all however the relationship between width and depth appears roughly the same. I'd like to get more throw and less flood from the light.
degarb
Flashlight Enthusiast
I would like an expert to comment on reflector depth and width, in relation to hot spot. . I have bought quit a few reflectors in my home made lights. . I believe, the reflector width, plays largest part in Hotspot intensity-so wider for more intensity. . I think deeper is for a brighter coronal spill, outside the Hotspot (believe the terminology goes).
My last t6 xml2 was 8k candela at 2 watts in a smooth 42mm, the xpl hi is 12k candela in a 35mm smooth, also at 2watts. The xpl hi is noticeably brighter, but has a weird purple color at Hotspot center that you can only see on white walls, which, for me is what I use them for. . The xpl hot spot is usually wide enough (it is possible to get too narrow since your visual "Hotspot" is 15 degree according to Wikipedia) and can be turned way down for insane runtime and still brighter task light than anything store bought. Though 35mm smooth for xpl hot spot balance is my current preferred reflector format.
My xpl v6 and hi are 4200kelvinish, warm as I ever want. I am told that tint is far more than CRI by people who have tested, scientifically. . One study even found people prefer lower CRI in some circumstances. I have zero opinion, I just am interested in seeing color differentiation, so far only very low CRI or dim lights have failed - for ex. I hate myepistar 65cri led 50watt for color, but have no issue with my 400 to 1000 watt mh lights. I also think my xpl's have better overall color rendering than my 2013 to 2015 xpls or and t6 china's bike lights. . Though the last t6 xml2 home build has good warm, for my taste, tint. I don't know why, probably spectral spike, but I haven't yet hobbled together my own spectrometer nor have looked yet for a Playstore spectrometer app. CRI is compared with heated metal under 5000k and the sun over 5000.
I would love to see a 600 lumen 4 watt xpl v6 or w2 based light bulb with 3 xpl emitters and efficient AC-DC and heatsink. . Though I would want a dimmer. . Not sure what premium I would be willing to pay.
My last t6 xml2 was 8k candela at 2 watts in a smooth 42mm, the xpl hi is 12k candela in a 35mm smooth, also at 2watts. The xpl hi is noticeably brighter, but has a weird purple color at Hotspot center that you can only see on white walls, which, for me is what I use them for. . The xpl hot spot is usually wide enough (it is possible to get too narrow since your visual "Hotspot" is 15 degree according to Wikipedia) and can be turned way down for insane runtime and still brighter task light than anything store bought. Though 35mm smooth for xpl hot spot balance is my current preferred reflector format.
My xpl v6 and hi are 4200kelvinish, warm as I ever want. I am told that tint is far more than CRI by people who have tested, scientifically. . One study even found people prefer lower CRI in some circumstances. I have zero opinion, I just am interested in seeing color differentiation, so far only very low CRI or dim lights have failed - for ex. I hate myepistar 65cri led 50watt for color, but have no issue with my 400 to 1000 watt mh lights. I also think my xpl's have better overall color rendering than my 2013 to 2015 xpls or and t6 china's bike lights. . Though the last t6 xml2 home build has good warm, for my taste, tint. I don't know why, probably spectral spike, but I haven't yet hobbled together my own spectrometer nor have looked yet for a Playstore spectrometer app. CRI is compared with heated metal under 5000k and the sun over 5000.
I would love to see a 600 lumen 4 watt xpl v6 or w2 based light bulb with 3 xpl emitters and efficient AC-DC and heatsink. . Though I would want a dimmer. . Not sure what premium I would be willing to pay.
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degarb
Flashlight Enthusiast
Woo Hoo! http://www.cree.com/News-and-Events...es-the-Next-Generation-of-High-Power-XPL-LEDs
The XP-l2 is here, meaning 200 lpw at 2 watts may be in reach. I am guessing at 1 watt, we will see the same lpw number as the xpl1. My take is this SC5 tech just helps pull the heat faster from the back of the led, which I am sure will be tested by members here up to 10 or 20 watts on useless short runtime lights, for a far droopier lpw rating. I think we all are tired of waiting for that 200 lpw led, when 303 lpw was reached in March 2014. Especially, after the table of heatsink requirement v. lpw was posted.
The xp-l2 is not on http://pct.cree.com/dt/index.html of of the date of this post. Naturally, I wonder when they will hit the online suppliers. I can't wait until Home Depot gets these in their Fall 2032 light lineup!
*My use: I am happy with the low heat/bright light output/improved color rendition, of my xpl v6, driven at 2 watts, 373 lumens (not quite as mentally satifying as "400 lumens at 2 watts"), 700 ma, with right (using 31mm, but 35mm on next build) reflector and 2x18650 buck cc/good heatsink-10 hours minimal runtime. Using a traditional cpu finned heatsink (jameco discontinued) + reflector holding sink, on my next build, I may get 200 lpw at 2 watt (measuring 373 lumens, now, with my intl-outdoor v6 neutral 4500k). Probably, a tad north of 170lpw at 3 watts, if I jump to a 2x26650 format. I am only interested in 10 hour target runtime, minimum-that is-, with a dimmer (on buck constant current controller, at over 90% efficiency).
The XP-l2 is here, meaning 200 lpw at 2 watts may be in reach. I am guessing at 1 watt, we will see the same lpw number as the xpl1. My take is this SC5 tech just helps pull the heat faster from the back of the led, which I am sure will be tested by members here up to 10 or 20 watts on useless short runtime lights, for a far droopier lpw rating. I think we all are tired of waiting for that 200 lpw led, when 303 lpw was reached in March 2014. Especially, after the table of heatsink requirement v. lpw was posted.
The xp-l2 is not on http://pct.cree.com/dt/index.html of of the date of this post. Naturally, I wonder when they will hit the online suppliers. I can't wait until Home Depot gets these in their Fall 2032 light lineup!
*My use: I am happy with the low heat/bright light output/improved color rendition, of my xpl v6, driven at 2 watts, 373 lumens (not quite as mentally satifying as "400 lumens at 2 watts"), 700 ma, with right (using 31mm, but 35mm on next build) reflector and 2x18650 buck cc/good heatsink-10 hours minimal runtime. Using a traditional cpu finned heatsink (jameco discontinued) + reflector holding sink, on my next build, I may get 200 lpw at 2 watt (measuring 373 lumens, now, with my intl-outdoor v6 neutral 4500k). Probably, a tad north of 170lpw at 3 watts, if I jump to a 2x26650 format. I am only interested in 10 hour target runtime, minimum-that is-, with a dimmer (on buck constant current controller, at over 90% efficiency).
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degarb
Flashlight Enthusiast
Since the xpl hi is an xpl, with no dome, I'd guess it goes without saying or press release. . I think my hi is now a v5 bin. . I am guessing binning might not change over just 7 percent which is within error range of one bin. With the r5 xgp2 binning stayed at r5 but knew it just could handle more heat with less droop in lumens. . Same with xml2 t6. . Assuming same here.
