How focus 445nm blue laser beam lens

[NotEntirelyEvil]

I looked for an existing thread on this before posting but didn't see one. Apologies in advance if I just missed it.

I just completed my first laser build and everything seems to be working, except that I can't get the laser dot to really focus. I've been screwing and unscrewing the lens to change the distance from the diode, but even when I get close to the "sweet spot", there's still a large, lopsided corona of light around the laser dot. See the attached image.

Here's the diode module I purchased: Link

The lens is a 3-layer glass lens, adjustable from 200nm - 1100nm that I had purchased with an Aixiz module previously.

Please advise on what I can best do to get the beam as effectively collimated to parallel as possible.

Thanks in advance!

 

[Tmack]

Flip that bad boy around

Have you disassemble the lens at all?
And is that as small as you can get it?

 

[crazyspaz]

Looks to me like the lens is in backwards. Just unscrew the silver focusing nut on the front, thread it on the other side, and you will be A-OK!

 

[Tmack]

That's what I meant by flip it around

 

[NotEntirelyEvil]

Fixed now.

:lasergun:

Thanks!

 

[Tmack]

What kind of host is that?

 

[NotEntirelyEvil]

I just grabbed an old external hard drive enclosure I had laying around, gutted it, drilled a hole for the diode assembly and power switch and then mounted the driver inside.

It works great--lots of space for heat diffusion and/or additional heat sinks, vents along the side for heat management, what I consider a quality look and feel, etc.

 

[Tmack]

Mount a little fan in that bad boy
Have it passing air right over your heatsink, and driver.

 

[NotEntirelyEvil]

You mean no liquid cooling? I suppose I'll have to find just the right LED fan. Maybe add a little SFX box to make Star Wars noises.

I've just crossed a dangerous threshold. This was my first electronics project and apparently making DiY "sci-fi" gadgets is highly addictive. :evil:

 

[Tmack]

Lol you got that right.

I've bought 5 9mm, 2 mitsu 500, 2 s0j6, 1 16x 405 drivers to match and a dozen hosts, in the last couple months. The majority went to their buyers, but that's a ton of money in parts!