Problem with Aixiz Laser Housing and Blu-Ray Diode - Need Advice

[arb26dettw]

Hi All,

I recently salvaged the blu-ray laser diode from a Sony Blu-Ray player and have built a driver circuit and purchased a blank Aixiz Laser Housing. The driver seems to properly power the diode so I placed the diode and driver into the housing. However, when the laser is turned on I am unable to focus it into a beam. I am able to focus the light to a point on something a few inches away, although once the light hits something further away, 10ft or so, it has expanded to a dot about a inch in diameter.

To me this is indicating that the beam is not collimating. Is there something that I could be missing or could there be an issue with the lens/diode.

Any help or hints would be greatly appreciated.

Thanks

 

[hakzaw1]

Did you properly press the die?
Are you using the stock acrylic lens or the glass AixiZ lens for 400-450 nm diodes?
maybe you have the lens backwords...Most if not all 405s make a very small dot--
something is not right. ..I will try to help- AixiZ cannot- the dont give detailed steps for builders-just sell the parts- if you send questions to them they send you to me so...take and post some pics- you will get answers from the forums.

GL----hak

There are many experts here at LPF--

 

[IsaacT]

I cannot find the thread, but IIRC I read that the Bluray diodes really need to be pressed past flush for the best focusing, but as I cannot find it I cannot confirm.

One thing I would do if I were you is go somewhere where you can point it at something quite a ways away. Turn the laser on and focus it such that the "tiny point" is far away. This is called focusing a laser "to infinity".

I think what is happening with yours is that because you are getting such a good focal point up close, your laser's beam is actually Converging(or getting smaller) and after the focal point, the laser diverges. If where you are focusing is close, you will have a larger rate of convergence towards your focus point, and in turn will have a larger rate of divergence, which I think would account for the inch sized dot at 10 ft.

Hope that helps,
Isaac

PS-when you want to burn something, don't pay attention to the dot it throws, it will always be huge because of where you are focusing it. BUT, if you want to use it as a pointer, then your goal is to have the laser beam stay constant over a large distance....try to make the thickness of the beam parallel.

 

[arb26dettw]

I am using the stock acrylic lens. The diode is definitely pressed into the housing fully into the recess.

I am definitely noticing that the lens is still creating a converging/diverging situation, hence the different dot sizes at different distances. I have tried to focus it on a far wall, however the best I can do is the previously mentioned 1" dot.

I also tried flipping the lens around but with no improvement in beam quality.

I am not interested in burning things with this laser so I am more focus on being able to create a very consistent beam.

If any pictures can help, let me know what you may want to see.

Thanks everyone.

 

[IsaacT]

If you have smoke in the room, a beamshot would probably be good, so we can see the entire profile of the beam.

Make sure to use Laser Safety Glasses when examining the size of the dot! I have noticed that 405nm tends to blur the dot larger due to the wavelength causing our eyes to fluoresce. Using Laser Glasses for this wavelength will eliminate the 405 blur and you will see the true dot.

Also, try having someone else focus the laser while you watch the dot WITH GLASSES ON. Then when you get it to a good spot you can tell them to stop and note the position.

One other thing that might help us help you is a video of yourself focusing the laser at a distance so that we can see the way the dot gets smaller or larger as you focus it and can also see how you focus it.

Thats all I can think of at the moment, if I thing of anything else I will edit my post.
Isaac

 

[Laser Smith]

I had a similar problem once witn an M140 and a G-1 lens. Turns out the barrel nut that holds the lens in place was loose

 

[grainde]

Does the focus ring bottom out on the heatsink, before you can focus it to a small dot?

I had that problem with an acrylic recently and it was because the acrylic barrel is much shorter than a 3 element glass lens barrel. That meant that the acrylic barrel screwed too deeply into the focus ring and hence the lens couldnt get close enough to the diode, before bottoming out. To solve that problem you can screw the barrel into the focus adapter (just a couple of turns ie not all the way in) and secure with some glue. If you dont want to use glue, wrap a very thin strip of electrical tape on the tip of the barrel to be screwed into the focus adapter instead. This makes it screw in very tightly and it will hold well after a couple of turns. :beer:

Edit: If you try this; take care not to get any glue or electrical tape on, or in front of, the lens and make sure the lens barrel is in the correct way ie lock nut on the barrel faces the diode..

 

[cheech226]

if i focus my 12x at a far wall the spot "looks" like over a inch because of the brightness. with laser glasses it is much smaller. not sure what kind of diode you have. can you try another lens?

 

[Blord]

Our eyes cannot see the 405nm light properly. After a few meters the dot becomes fuzzy and our eyes can't focus it. You must shine the laser on a distant wall and walk over there to look at the dot from a close distance.
See if the dot is still collimated. Be careful walking back to the laser.