Questions regarding reflector

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josith
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Questions regarding reflector

Hi guys, i am new at this. and i have a few questions.

1.  how come different led requires different reflector?  the way i understand it is that a reflector would send any light coming from the focal point straight out, right?  why do we need a different reflector for xre, mce, xml, etc.?

2.  shouldn't led with larger viewing angle throws better since more light comes out on the side and touch the reflector?

3.  given the same led and driver, what throws further, aspherical lens or reflector (hum.... such as the reflector in HS-802)?  does the size of the aspherical lens matter?

i tried googling and no luck. thanks in advance.

Don
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1) Different LEDs have different die (The bit that actually emits light) sizes and beam angles. The smaller the reflector, the more important that it matches the emitter.

2) Surface brightness is essentially what determines throw - the highest output from the smallest area/volume is what we want for throw.

3) Depends. There is probably a theoretical answer but I don't know what it is. Lenses, reflectors, the bigger the better. Till you have to carry them around...

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

josith
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thanks for the quick reply Don.

lets see if i understand this correctly.

throw depends on the concentration of the light beam.  and the concentration depends on two factors.

1. light exiting the flashlight directly from the LED and 2. light reflected by the reflector and then exit the flashlight, and out of these two factors, factor #1 is more important.

to maximize factor#1, we need high surface brightness and small beam angle, and that's why xre is the best choice. am i right so far?

i am really curious about factor#2, the reflector.  how do u determine what is best for xre, mce, xml, etc ?  is it the diameter of the reflector, depth, shape (such as parabolic, spherical....) or the more reflected surface the better?  or u don't know it until u try it? is that why u guys have so many lights?

Piers
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Assuming the XM-L I ordered from KD ever turns up it's going in a Solarforce Skyline 1, because the die size is a lot larger than the current emiter the light will be a lot less focused than the current setup.

So instead of getting the "white laser" effect it will be a wider hotspot, there will be a lot more light though of course so the comparison should be intresting.

josith
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well Pook, that sounds interesting. if u have a beam shot of the original and xml skyline that would be great.  i really wanna understand what makes a light throw. there are too much information out there, some make sense some don't.  i guess i will have to order some more throwers to find out.

Piers
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I certainly will do side by side beem shots when/if the parts arrive Smile