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Bluray focus and yellowing

A

adcurtin

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I got a blu-ray diode from the GB, and I can't seem to get it to focus. I have an AixiZ housing. It also has some yellow in the spot. I read that I should put more current through the diode to get rid of this, but I put enough current through the diode to make the housing warm, and the yellow is still there.
 





Sometimes it doesn't go away. Ever. In my experience The blu-ray lasers require much smaller rotations of the focusing ring than either red or green lasers. I find it easiest to put a white piece of paper on a wall 15 feet in front of me and then try to make a blue dot about the size of a pea on it. It is too hard to do while the dot appears violet, our eyes aren't made to focus on that wavelength.
 
mine is the same way im trying to figure out how to make my current go higher i think i might change resistors to a 32 ohm besides a 33 ohm
 
......much smaller rotations of the focusing ring than either red or green lasers
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Just what I have found, just a few degrees make all the difference, there is a sweet spot in there somewhere you just need to find it :) Unless the problem is that the LD is not inserted in the housing straight or, as happened on my third build, I had a broken LD window.

I am intrigued by the number of posts mentioning the yellow patch, when I had it , on my first build, low voltage was most definitely the problem. I only changed the input voltage, not the output, (ie I did not change the resistor value), the output is now near perfect.

Regards rog8811
 
it also helps if you have a fog machine, much easier to visualize the beam spread
 
i can set a bomb fire and i can marly see my beam lol i no its not dead it just not brite enough
 
I still say that the reason we cannot focus the blue ray properly is because we do not have the right lense for that wavelength. That is the only and best answer.

P.S. If anyone knows how we can get the proper optics please post it.
 
I have built four blue-rays, three of them are in perfect focus, the fourth, due to the partly missing window is not as good a dot but usable.
They are all fitted into standard DX (same as Aixiz) modules with standard lenses.

I think you need to look elsewhere for the problem.

Regards rog8811
 
Well I have tried focusing mine time and time again but the outcome is still the same. I can focus it into a small dot but if I were to shine it on something closer or farther than the focused point it is a larger dot. If I try focusing it on something in the distance then the dot for an object up close is worse. I have had no problem focusing a high powered red. So rog8811, if you say it is not the lense then what is it? And what do you mean by partly missing window?
 
He is saying that the little window onfront of his diode has cracked, and abit has fallen out. I have heard that acrylic lenses flouresce at UV wavelenghts. Though the glass ones should be fine.
 
BTW i too have seen the yellow emmision, but with the amount of people reporting it, it must just be a common thing. My guess is that it is causing a small part of the other laser dies piled underneath the bluray die, to lase.
 
Things said:
BTW i too have seen the yellow emmision, but with the amount of people reporting it, it must just be a common thing. My guess is that it is causing a small part of the other laser dies piled underneath the bluray die, to lase.
Click to expand...

Uhh, I thought these were diodes.
 
aaronX987 said:
Well I have tried focusing mine time and time again but the outcome is still the same. I can focus it into a small dot but if I were to shine it on something closer or farther than the focused point it is a larger dot. If I try focusing it on something in the distance then the dot for an object up close is worse. I have had no problem focusing a high powered red. So rog8811, if you say it is not the lense then what is it? And what do you mean by partly missing window?
Click to expand...

blurays are harder to see the dot which makes it harder to collimate properly. The dot from a bluray is going to be very large so when you focus it to a small dot it's not focused properly. Again it helps to use fog so you can see the beam, then focus it so the beam does not converge or diverge
 
You can also use a white paper to turn it blue, which is much easier to see. The best way to focus the beam, IMO is to aim it to a mirror about 6 meters away and then back on the wall a few ceniteters from the laser.
 
Yellow glow means either the lenses are florescent or the diode was defective or over loaded with either DC or ESD that caused ion migration in the current carrying channel and or quantum wells - in that case means imminent failure withing about 200 hours. On microscope inspection of the die i cannot believe some of these things even lase at all!

That's the big problem with nitride lasers, ion diffusion in the quantum wells giving a non lasing vibrionic transition to a metastable state giving off yellow light that competes with the violet laser transition in the quantum wells. The problem gets way wores as the amount of indium is increased so it's far worse with the "bluer" ones!
 
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