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Cree X primary optics ! (do they even exist??)

  • Jerommel Tuesday, March 18, 2014 4:09 AM Reply

    Got a C8 and a C5 just in.

    Immediately popped in a XM-L2 neutral white ;)
    An aluminium reflector certainly has problems with the colour distribution... :/
    Because it only focusses the 'outer rays' coming from the LED, the hot spot is warm white, while the flood is cool white...
    That doesn't make me happy :(
    The 'orange peel' reflector obviously doesn't solve this either...
    But, it smoothens the lot nicely. :)
    Standard driver, I guess it's 1.5A in HI mode.
    Put an aluminium washer between LED-star and aluminium reflector for focussing and heat transmission to the reflector.
    Because the pill is hollow, only the sides of the star make thermal path with the pill..
    So I decided to let the reflector join in as heat sink.
    I used some thermal goo too..
    A very effective torch it is. :)
    I will pop in a decent driver soon, get it to some 2.5A :D

    Looking for something now with extremely deep (and/or narrow) reflector, but I hate to spend more than $10,-- :P

    A zoom torch with a lens focusses (only) the best bit of light, coming from the front of the LED.

    Very nice results with a 21mm PMMA reflector (I believe some say "TIR" ?) in the C5 though, With an XP-G2 'neutral white' (which turns out to be somewhat pink-ish :/ )
    Not the colour problem at all with that.
    It has 'orange peel' (or pebbled) surface.
    It fits tight inside the chromed plastic reflector, so all light gets reflected forward, or at least outward..
    (I should check if it makes a noticeable difference, but I like the thought..)
    Standard driver, I guess HI mode is around 800mA.
    A lot of light!
    Very compact torch too.
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  • desolder Top 10 Forum Poster Tuesday, March 18, 2014 5:14 AM Reply
    $10 price is going to be pretty tough to get under. Another vendor is selling a Ultrafire C10 DIY body for a little over $10. The C10 reflector is slightly deeper than the C8.

    Which 21mm PMMA optic did you use? Was it a DX sku?
    What's up with the scrubbed LED driver IC markings?
    What are they trying to hide?

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  • Jerommel Wednesday, March 19, 2014 4:28 AM Reply
    It's SKU 235237
    Haven't tried the LG LEDS yet though, but they seem to be good at 1 watt, giving around 100LM

    on some fast store they sell a torch with much deeper reflector.
    Looks like a lengthened C8 (taller head obviously) but it's some $ 18.--
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  • Jerommel Thursday, March 20, 2014 7:47 PM Reply
    De-doming LEDs.
    Put an XLamp in car fuell and the dome will fall off, practically clean if you leave it for a day to soak.
    Also interesting..

    Anyway, better to discuss all this at some dedicated forum,I guess..
    Lots to learn and try.
    Will have to take up on reflowing emitters too..
    Boy, will I have lumens on batteries! :D
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  • desolder Top 10 Forum Poster Thursday, March 20, 2014 11:47 PM Reply
    Interesting technique to de-dome the LED. When the dome falls of, wouldn't that leave the bonding wires exposed?
    What's up with the scrubbed LED driver IC markings?
    What are they trying to hide?

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  • Jerommel Friday, March 21, 2014 6:31 AM Reply
    Yes, it will leave them exposed, making them extremely fragile to touch.
    They're gold (or gold plated?), so no worries about corrosion.
    But I understand it gives more throw and less rainbow effect, i.e. better for use with a reflector.
    I also understand it does not improve performance in a zoom torch (i.e. with a lens), as the dome normally pre-focusses the emitter somewhat.
    I have an obsolete XP-E soaking in car-fuel right now.
    After a couple of hours, shaking the tiny glass, the dome washed off, but still some residual stuff on the die
    I'll check the results tomorrow.
    Maybe with a very small and soft painters brush wipe it clean, if that's still necessary.
    Next up to soak and decapitate will be an XM-L, so I can try it in a C8.
    With good results I'll try an XM-L2 too.

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  • Jerommel Friday, March 21, 2014 6:48 PM Reply
    Funny though, starting some topic about primary CREE optics, and now discussing the removal of the primary optics, because in fact the LEDs mentioned already have primary optics: The silicone dome...

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  • gasbag11 Top 10 Forum Poster Friday, March 21, 2014 8:14 PM Reply
    I'll admit I don't know much (okay, almost nothing) about the tech. aspects of leds or the electronics involved with them, but I was under the impression that part of the reason for the domes (aside from protection) was to direct light to the side, toward the reflector. Wouldn't de-doming make most of the light go straight out the front? Since the reflector is what focuses the light into the center beam and makes a light a "thrower", it seems to me that de-doming would increase the amount of un-focused light, making the "spill" brighter. Do I have it backwards?
    NO! I don't know why DX screwed up the site so badly.
    Ask them.
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  • Jerommel Saturday, March 22, 2014 1:53 AM Reply
    ...sdrawkcab ti evah uoy diarfa m'I

    The dome is in fact a plano-convex lens, so it bundles it.
    But I still have a lot of experimenting to do to be able to tell you more with certainty.
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  • desolder Top 10 Forum Poster Saturday, March 22, 2014 8:12 AM Reply
    Here's a good writeup by DrJones on de-doming with some optics theory:

    What's up with the scrubbed LED driver IC markings?
    What are they trying to hide?

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