I am attempting to focus a laser diode which has a set of focus parameters from 20mm to 45mm as shown below:
I adjusted the distance of the laser to be 20mm from the face of the lens to the workbase. I used light burn using the fire button on a piece of poster board. Notice it burned a “slot” shown here:
Well, I made the mistake of not marking the location of the focus ring before attempting to focus it better. Thru my safety glasses, no matter which way i turn the ring, this is all i see thru my glasses. “a slot image”. that doesn’t change. I have tried a web cam and its just over saturated. any ideas?
A few things to look at:
- Use the lightest possible power to where you can see the light. This will help reduce blooming.
- Use a non-reflective dark material where possible. A dark matte cardstock can be useful.
- If you still can’t see it consider getting a microscope. A USB microscope makes this relatively easy.
- Alternatively, use a ramp test to determine whether or not you’re in focus.
One thing to look out for… for lasers with a focus ring the lens can wiggle around in the barrel enough to where it can throw off laser focus and angle the focus beam. Some teflon tape around the barrel can remove that play. Just make sure you don’t have stray strands obscuring the lens in any way.
