raggie33
*the raggedier*
- Joined
- Aug 11, 2003
- Messages
- 13,493
will we ever see it? will we ever see 20,000?sems like every day leds inprove.
15,000 lux?
- Thread starter raggie33
- Start date
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B@rt
Flashaholic
With proper optics it is easily doable already, but you would end up with a very tight beam... /ubbthreads/images/graemlins/frown.gif
A more accurate way would be to ask if there will be an increase in lumens. /ubbthreads/images/graemlins/wink.gif
A more accurate way would be to ask if there will be an increase in lumens. /ubbthreads/images/graemlins/wink.gif
According to this webpage http://www.pocketlights.com/shot_show_2004_day1.asp#inova there is a X0, supposedly capturing 92% of the light coming out from a LS, takes 2 123, 8 hours run time, has a mineral lens, and retails for $59. Maybe it's like the X-1 and has a super tight spot?
Icebreak
Flashlight Enthusiast
Some of the ModMen have surpassed 15K lux with heavily sinked, overdriven, SNII inspired 3 watters. I could have almost sworn I saw a post by a knowledgeable and skilled member that recently attained 20K lux but I can't remember the thread.
Dern, raggie. Now I have figure it out. Worse than a tune playing in my head and can't think of the song name or artist. Thanks, buddy. Now I know what I'll be talking about today.
I think Black Bert has the better question...measured in lumens. Of course, these triple LEDs that have attained some popularity have massively increased LED lumen output expectations.
Did I just say Black Bert? Glad he's a friendly Administrator.
Dern, raggie. Now I have figure it out. Worse than a tune playing in my head and can't think of the song name or artist. Thanks, buddy. Now I know what I'll be talking about today.
I think Black Bert has the better question...measured in lumens. Of course, these triple LEDs that have attained some popularity have massively increased LED lumen output expectations.
Did I just say Black Bert? Glad he's a friendly Administrator.
B@rt
Flashaholic
Icebreak
Flashlight Enthusiast
erm...
...for the first time on this board, I'm speechless. /ubbthreads/images/graemlins/grinser2.gif
...for the first time on this board, I'm speechless. /ubbthreads/images/graemlins/grinser2.gif
Jarhead
Banned
That was blown away long ago, with a 3W LED.
This light meter has multipliers that are indicated by the two 00, which you add to the 3250, for 32500 lux. It peaks to 36,000 to 40,000 lux when I can hold the Luxeon steady, took like 10 shots to get that. Add on that I'm trying to hold the camera with the other hand, and that I've had surgery on both hands that is healing.... If you look carefully, you can see that it is not centered.
Note it is on the Fluorescent range, which causes a big drop in the reading, otherwise it it up around 40,000 lux for the incandescent reading that most folks use on the board here.
Thats a 3W at 1 meter with a aspherical lens.
This light meter has multipliers that are indicated by the two 00, which you add to the 3250, for 32500 lux. It peaks to 36,000 to 40,000 lux when I can hold the Luxeon steady, took like 10 shots to get that. Add on that I'm trying to hold the camera with the other hand, and that I've had surgery on both hands that is healing.... If you look carefully, you can see that it is not centered.
Note it is on the Fluorescent range, which causes a big drop in the reading, otherwise it it up around 40,000 lux for the incandescent reading that most folks use on the board here.
Thats a 3W at 1 meter with a aspherical lens.
raggie33
*the raggedier*
- Joined
- Aug 11, 2003
- Messages
- 13,493
wow thats pretty cool.but now i think i should of asked about lumens. im wondering if its like cpu todays cpu will look drab in a year
The_LED_Museum
*Retired*
To get lumens, you need something called an "integrating sphere", and nobody here on CPF owns one. /ubbthreads/images/graemlins/jpshakehead.gif
Not that I know of, anyway. /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/frown.gif
Not that I know of, anyway. /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/frown.gif
Jarhead
Banned
Well, I'm looking at a LumiLEDs presentation right now that is showing for February 2004:
55 lumens per emitter for the 1W
120 lumens per emitter for the 3W
215 lumens per emitter for the 5W
They missed four milestones alreadly along the way,
since 2002.
These are parts they "already had in the lab" and
these were the milestones for moving them to production.
Either they are waiting for challengers, before they
release these parts to full production, they are trying
to get the biggest bang for as long as they can out of
existing parts, they had production "issues", or they were
fibbing a bit.
Remember, these were supposedly parts they'd already built,
and had in the lab, and they have missed four milestones already.
The fifth milestone for May 2004:
60 lumens per emitter for the 1W
140 lumens per emitter for the 3W
245 lumens per emitter for the 5W
So, where are these, "we have them already parts?"
Also folks don't look at the datasheets too careful.
When they say an emitter puts out 25 lumens, you'll
note on the datasheet that it says Tj= 25 degrees C.
I have not seen a flashlight that is heatsinked/cooled
well enough to hold the junction temp at 25C.
If you look at the datasheet for the emitter, you will
see a Light Output Characteristics section. The one
I am looking at right now shows the light output dropping
by 30% when the junction reaches 120 degrees C.
Note they claim the die to slug thermal resistance of 15 degrees C per watt. So, if you had an infinte heatsink, which a flashlight is a *far* cry from that. Even if you could hold the flashlight at a room temperature of 25C, and you
had perfect thermal coupling from the flashlight body, to the thermal puck, and perfect coupling then to the Luxeon slug, and held the Luxeon slug at 25C, you'd still get a 5% drop in light output. Since we don't have all this perfect stuff, most luxeons probably have a much greater loss of light output due to heat. The ARC4 would be a perfect example of a LED in a setup that doesn't hold the LED slug at 25 degrees C.
Consequently, also look at the increase in light output if you cool the Luxeon below this. If you get that slug down to -50C, you get more than a 20% increase in light output.
Now, you toss in a 3W LED. Hold the slug at 25C, but we have 3W now (if you only hit it with like 700mA), but at 15 degree C rise in the LED die per watt. So, if we could do the impossible and hold the flashlight, heatsink puck, and the LED slug at 25 degrees C, the LED junction would rise by 15 * 3W = 45 degrees. 25 + 45 = 70C junction temp. Now we have a 15% loss in light output. But, because we don't have all this perfect stuff, you see a much greater drop than 15% drop in light output levels.
Then you take a look at the optics/lens/reflector/protective lens cover and you end up with a bunch of additional losses. Most extremely highly polished aluminums put on a reflector will only have 70-80% reflectivity. (this will degrade once develops it's characteristic aluminum oxide film due to our atomsphere) So, toss in another 20-30% loss. Of course, a person can go the spendy route, beyond flashing, and get a vacuum deposited telescope mirror type coating applied, with a protective coat, and dream of getting these losses down to only 2%.
Still we need the protective lens, a nice uncoated lens will give you about 8% loss, tack on another 6% per millimeter if you use standard float glass. Add on a real nice Broad Band Anti-Reflective coating, and you can get to 0.5% loss per surface (front and back), and then the loss of the glass itself.
And then you get to converters. Take a BadBoy boost converter, say you want to run that 3W at 1A, so you get a BB1000. Well, you stick two NiMH in the flashlight, and at 1A, the input voltage drops to 2.4V in a hurry, which causes further current requirements from the batteries, since it has to boost further. Before you know it, you are sitting at 60% electrical conversion efficiency. Thats a huge hit on runtime, and that 40% loss is going to turn itself into heat. Guess what? The luxeon then gets warmer, and the light output drops even further...
So, there are lots of areas a person can attack to improve the light output levels of flashlights.
Just my two cents...
55 lumens per emitter for the 1W
120 lumens per emitter for the 3W
215 lumens per emitter for the 5W
They missed four milestones alreadly along the way,
since 2002.
These are parts they "already had in the lab" and
these were the milestones for moving them to production.
Either they are waiting for challengers, before they
release these parts to full production, they are trying
to get the biggest bang for as long as they can out of
existing parts, they had production "issues", or they were
fibbing a bit.
Remember, these were supposedly parts they'd already built,
and had in the lab, and they have missed four milestones already.
The fifth milestone for May 2004:
60 lumens per emitter for the 1W
140 lumens per emitter for the 3W
245 lumens per emitter for the 5W
So, where are these, "we have them already parts?"
Also folks don't look at the datasheets too careful.
When they say an emitter puts out 25 lumens, you'll
note on the datasheet that it says Tj= 25 degrees C.
I have not seen a flashlight that is heatsinked/cooled
well enough to hold the junction temp at 25C.
If you look at the datasheet for the emitter, you will
see a Light Output Characteristics section. The one
I am looking at right now shows the light output dropping
by 30% when the junction reaches 120 degrees C.
Note they claim the die to slug thermal resistance of 15 degrees C per watt. So, if you had an infinte heatsink, which a flashlight is a *far* cry from that. Even if you could hold the flashlight at a room temperature of 25C, and you
had perfect thermal coupling from the flashlight body, to the thermal puck, and perfect coupling then to the Luxeon slug, and held the Luxeon slug at 25C, you'd still get a 5% drop in light output. Since we don't have all this perfect stuff, most luxeons probably have a much greater loss of light output due to heat. The ARC4 would be a perfect example of a LED in a setup that doesn't hold the LED slug at 25 degrees C.
Consequently, also look at the increase in light output if you cool the Luxeon below this. If you get that slug down to -50C, you get more than a 20% increase in light output.
Now, you toss in a 3W LED. Hold the slug at 25C, but we have 3W now (if you only hit it with like 700mA), but at 15 degree C rise in the LED die per watt. So, if we could do the impossible and hold the flashlight, heatsink puck, and the LED slug at 25 degrees C, the LED junction would rise by 15 * 3W = 45 degrees. 25 + 45 = 70C junction temp. Now we have a 15% loss in light output. But, because we don't have all this perfect stuff, you see a much greater drop than 15% drop in light output levels.
Then you take a look at the optics/lens/reflector/protective lens cover and you end up with a bunch of additional losses. Most extremely highly polished aluminums put on a reflector will only have 70-80% reflectivity. (this will degrade once develops it's characteristic aluminum oxide film due to our atomsphere) So, toss in another 20-30% loss. Of course, a person can go the spendy route, beyond flashing, and get a vacuum deposited telescope mirror type coating applied, with a protective coat, and dream of getting these losses down to only 2%.
Still we need the protective lens, a nice uncoated lens will give you about 8% loss, tack on another 6% per millimeter if you use standard float glass. Add on a real nice Broad Band Anti-Reflective coating, and you can get to 0.5% loss per surface (front and back), and then the loss of the glass itself.
And then you get to converters. Take a BadBoy boost converter, say you want to run that 3W at 1A, so you get a BB1000. Well, you stick two NiMH in the flashlight, and at 1A, the input voltage drops to 2.4V in a hurry, which causes further current requirements from the batteries, since it has to boost further. Before you know it, you are sitting at 60% electrical conversion efficiency. Thats a huge hit on runtime, and that 40% loss is going to turn itself into heat. Guess what? The luxeon then gets warmer, and the light output drops even further...
So, there are lots of areas a person can attack to improve the light output levels of flashlights.
Just my two cents...
Jarhead
Banned
I'm looking for where I put my link, but here is an old roadmap in here that can be interpeted from 2001,
http://www.lumileds.com/pdfs/techpaperspres/MD2002.pdf
It is also shown here:
http://www.lumileds.com/pdfs/techpaperspres/SID-BA-Paolini.pdf
See Page 19 for greater than 60 lm/W in lab, see page 10
for the greater than 10 Watt LED reference (Mike Krames is one of the head lab "scientists" at LumiLEDs, you'll see him referenced in lots of papers and patents):
http://www.netl.doe.gov/ssl/PDFs/Krames.pdf
http://www.elecdesign.com/Articles/Print.cfm?ArticleID=2254
May 2002:
"In the same application, the current generation of Luxeon LEDs would draw about 25 W. But LumiLeds' roadmap says that value should drop to 11 W by next year."
I've also seen references to a high thermal conductivity PCB that when combined with the LED die, result in 6-12 C/W, which would increase the light output. Here is one,
page 10, figure 5.
http://www.crd.ge.com/cooltechnologies/pdf/2002grc078.pdf
However, I can't find the link where I got this Luxeon efficacy roadmap, it is from 2002.
http://www.lumileds.com/pdfs/techpaperspres/MD2002.pdf
It is also shown here:
http://www.lumileds.com/pdfs/techpaperspres/SID-BA-Paolini.pdf
See Page 19 for greater than 60 lm/W in lab, see page 10
for the greater than 10 Watt LED reference (Mike Krames is one of the head lab "scientists" at LumiLEDs, you'll see him referenced in lots of papers and patents):
http://www.netl.doe.gov/ssl/PDFs/Krames.pdf
http://www.elecdesign.com/Articles/Print.cfm?ArticleID=2254
May 2002:
"In the same application, the current generation of Luxeon LEDs would draw about 25 W. But LumiLeds' roadmap says that value should drop to 11 W by next year."
I've also seen references to a high thermal conductivity PCB that when combined with the LED die, result in 6-12 C/W, which would increase the light output. Here is one,
page 10, figure 5.
http://www.crd.ge.com/cooltechnologies/pdf/2002grc078.pdf
However, I can't find the link where I got this Luxeon efficacy roadmap, it is from 2002.
Hey Jar... if that was 2 cents, I wonder what 4 cents will buy me. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
What you've said is 100% correct. I guess the manufacturers have been forced to give us a rating for light output because everyone of us wants to know how much light their flashlight puts out and instead of explaining the real truth like you did above, at which point the person asking the question would have lost track of their initial reason for asking the question /ubbthreads/images/graemlins/wink.gif, they simply quote a figure that is claimed by the LED manufacturers.
What you've said is 100% correct. I guess the manufacturers have been forced to give us a rating for light output because everyone of us wants to know how much light their flashlight puts out and instead of explaining the real truth like you did above, at which point the person asking the question would have lost track of their initial reason for asking the question /ubbthreads/images/graemlins/wink.gif, they simply quote a figure that is claimed by the LED manufacturers.
Jarhead
Banned
Hotbeam,
Another little trick is to make the measurement when they first turn on the flashlight, to get the numbers before anything heats up.
As always, if they can fudge the number somehow, they often will.
Another little trick is to make the measurement when they first turn on the flashlight, to get the numbers before anything heats up.
As always, if they can fudge the number somehow, they often will.
