5mm LEDs and parabolic reflectors

Ilikeshinythings

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I'm not really familiar with the reflective properties of 5mm LEDs so my question is how would a 5mm LED work if it were used in conjunction with a larger reflector?

the Fenix E01 and Arc AAA both use tiny reflectors to achieve decent spill and a decent spot, but what would the outcome look like if the 5mm LED were used with, say, the reflector from a streamlight Strion, or an even larger reflector?

My guess is that since they are not that bright, there would be little side spill and a very tight spot--am I correct in assuming this?
 

R@ndom

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I'm not really familiar with the reflective properties of 5mm LEDs so my question is how would a 5mm LED work if it were used in conjunction with a larger reflector?

the Fenix E01 and Arc AAA both use tiny reflectors to achieve decent spill and a decent spot, but what would the outcome look like if the 5mm LED were used with, say, the reflector from a streamlight Strion, or an even larger reflector?

My guess is that since they are not that bright, there would be little side spill and a very tight spot--am I correct in assuming this?

A real reflector will be pointless as the optics are the LED itself. The reflector just direct some of the light going sideways forward.
 

lightforce2

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I have one of these with 3 leds surounding the 30w xenophot globe, they aren't in the the focal point however the 170mm reflector generates enough forward light for use as a walk light, very handy!!

enf.jpg
 

Narcosynthesis

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A 5mm LED is designed as a standalone item - because of the positioning and dome shape it has the lens incorporated into it - which is why you see lights like the e01 with tiny (and pretty ineffective) reflectors (really more as a protection to the led) or lights with the led completely exposed.
 

Hondo

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+2, STANARD 5mm's focus through the dome, and the "reflectors" on the lights you mentioned do almost nothing. If you were to pull the pill and power it up outside the head, you would not notice the difference. Also, if you inserted it into a monster reflector, the beam out the front would be the same, since it comes from the tip of the LED lense, not from a reflection off of the reflector.

Now, 5mm's like the MJLED, where the dome has been ground to a near flat just above the die, will throw their light out to the sides like a power LED does, and will REQUIRE a reflector to get any kind of throw or hotspot from them. The PR2 conversion bulbs from the Sandwich Shoppe use these, and they sell the loose LED's, ground or conventional. Note that just grinding the dome off of something like a Nichia CS, DS etc. and re-polishing it will not work quite so well, as the innards of those MJLED's and SMJLED's is somehow different in a way that makes this possible. I have put these things in large reflector lights and gotten a near laser-like beam from them, with more throw than many of my power LED lights.
 

Ilikeshinythings

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+2, STANARD 5mm's focus through the dome, and the "reflectors" on the lights you mentioned do almost nothing. If you were to pull the pill and power it up outside the head, you would not notice the difference. Also, if you inserted it into a monster reflector, the beam out the front would be the same, since it comes from the tip of the LED lense, not from a reflection off of the reflector.

Now, 5mm's like the MJLED, where the dome has been ground to a near flat just above the die, will throw their light out to the sides like a power LED does, and will REQUIRE a reflector to get any kind of throw or hotspot from them. The PR2 conversion bulbs from the Sandwich Shoppe use these, and they sell the loose LED's, ground or conventional. Note that just grinding the dome off of something like a Nichia CS, DS etc. and re-polishing it will not work quite so well, as the innards of those MJLED's and SMJLED's is somehow different in a way that makes this possible. I have put these things in large reflector lights and gotten a near laser-like beam from them, with more throw than many of my power LED lights.

Thanks to you and the others for answering my question.

Now, you say you used MJLED's and SMJLED's (btw, can you please explain what those stand for and what they are) in "larger" reflectors with near laser-like output...how big were the larger reflectors you used for these results? And if you were to use a marginally smaller reflector would you see a more useable hotspot and perhaps more sidespill?

One last question, which lights out there use either a ground-down MJLED or SMJLED?

I would like to see a light that uses two D cell batteries and powers one of these ground-down LEDs with some sort of a reflector setup. I think it would be a great walking light and could probably achieve a runtime of >30 hours.
 

Lynx_Arc

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Thanks to you and the others for answering my question.

I would like to see a light that uses two D cell batteries and powers one of these ground-down LEDs with some sort of a reflector setup. I think it would be a great walking light and could probably achieve a runtime of >30 hours.

2D cell lights driving a high power LED will run for ~30 hours at brightnesses starting out a lot better than your lower power LED idea and then fade to better than a 5mm LED for hours and hours before the batteries are depleted. I would recommend looking for 2D LED lights or a drop in for a light. Putting a 5mm or an SMJled in a 2D light will get you possibly over 200 hours of unimpressive dim light.
Alkaline D cells at low current drains (less than 100ma have up to 18,000mah capacity to them so a 100ma draw would last 180 hours while a 200 mah draw would probably last around 40-60 hours as the current increases capacity drops (internal battery resistance adds in more)
 
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