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Thread: 445 Diode Selection

  1. #1
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    Default 445 Diode Selection

    I have been trying to tightly knife edge a group of 445 diodes and I am now more acutely aware of the two general near field beam patterns when the O-like collimator is used . One is a thick and sharp central strip flanked by two equally sharp, but thinner and dimmer strips. The other is a more diffuse single strip whose overall width is the same as the entire three strip array of the first pattern. Most of my diodes fall into the first type and as these are easier to tightly knife edge and they also form a slightly sharper far field I'm wondering what other people are seeing; what ratio of sharp/diffuse diodes when ordered? Is one type more common with a particular projector series?

  2. #2
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    At what current?

    When I knife edge mine, all the ones I've used would match your first "sharp" description (A140 diodes @ 1.25A), I take the middle stripe and the right-hand 1st order stripe, cutting out the left-hand stripe. This yields ~4.0W raw -> 3.2W combined. *from 4 diodes.
    Last edited by danielbriggs; 11-07-2011 at 08:43.
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  3. #3
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    My diodes are all run at approximately at 0.8 A for alignment and I too cut out the first side stripe on its first mirror intercept and then cut out the second side stripe when it fails to pass the backside of the next mirror upstream. Many of my diodes ( but not all) come from a 130 series projector.

  4. #4
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    Shot in the dark: maybe the collimators are ever so slightly out of focus?

  5. #5
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    No that definitely is not it. When a "bad" diode is even approaching focus you already know it. And I've tried exchanging lenses with no effect. With no record of the source of a given diode these may all be from a 130 series harvest. No way to check this. Not a problem though if the general consensus is that the vast majority of the now available diodes are crisp /three-line in the near field then I'll just retire these and take my chances on purchasing some more diodes.

  6. #6
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    How different do the beam profiles look without a collimating lens?

  7. #7
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    I'll have to look at this

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