Phr-805t laser won't focus properly

I just built myself a violet laser. It is a PHR-805t diode housed in a leadlight host. It is using the standard AixiZ lens that came with the module. When it is focused as close to infinity as it gets, the dot is still huge. When I shine it at the wall from about 5 feet away, the dot is like 3-4 inches wide. There is also a speck of dirt on the window on the diode itself, so I can see that speck of dirt on the dot on the wall. How can I fix these problems?
Thanks

i think your diode is broken or the dirt is making it unfocusable

or buy a 405/445 nm glass lens

Make sure the lens is not backwards. Also make sure the diode is countersunk in the module.

Shine it on a black surface and see if the dot is large when focused to a point. If it starts burning the black material then you should be fine. Do you have goggles? If you have goggles it will show you the true dot size.

The dirt is prolly on the lens. Use 90% alcohol and a Q-tip to clean both sides.

Check the raw output of the diode. Shine the laser on the wall without the lens.
The output must be very even and smooth across the area.

If the edges is very sharp like this and the dot is perfectly round like this (this one is red, but the same for violet):



The lens is inserted backwards

Without pictures this is a guess
Also, with the advent of the 445, we don't talk about these as much, so the info is "buried" a bit

First, the 405 requires the lens to be a bit closer than others.
I would think that you need to remove the focus ring and screw the lens in a bit farther
If the lens bottoms out, then the diode was not pressed deeply enough into the module
The 405 actually needs to be pressed BELOW/PAST the back surface of the module

This picture is actually for one of the Merideth adapters, but it shows what I am talking about
If you used the "back half of the module" pressing technique, this could be the problem


Second possibility is simply that the 405 is harder to "see"
If the above doesn't help, then have someone else shine the laser and actually go down to the wall to see how "big" the spot really is
It may just "look" big from where you are standing

As far as the "speck of dirt" is concerned, rotate the lens while the laser is on.
Does the "mark" move with the lens?
If so, the dirt or blemish in on the lens
One can rarely actually "see" dirt on the diode window
When the diode window is dirty, either the output is lower or the spot is misshapen

Peace,
dave

Daguin, I believe it is because I used the back-end-of-the-module pressing technique. I took the focus ring off the lens and screwed it in further with my fingers. It was almost all the way in when it reached infinity. but no, the speck does not rotate when I turn the lens. I would take pictures of it to show you, but my "camera" (the crappy camera on my ipod) just shows a big bright blue dot on the wall. But also, there is a very noticeable lens artifact. To fix that I would have to buy a better lens, correct?

BlackWidow said:

Daguin, I believe it is because I used the back-end-of-the-module pressing technique. I took the focus ring off the lens and screwed it in further with my fingers. It was almost all the way in when it reached infinity. but no, the speck does not rotate when I turn the lens. I would take pictures of it to show you, but my "camera" (the crappy camera on my ipod) just shows a big bright blue dot on the wall. But also, there is a very noticeable lens artifact. To fix that I would have to buy a better lens, correct?

Click to expand...

Well, at least we have it usable without rebuilding it

Interesting about the "speck". Unfortunately, cleaning diode windows is a risky endeavor.
However, with regard to both the "speck" and the lens artifact, as long as it looks OK while it is focused, they really don't matter, do they?
You don't really need to look at the expanded (unfocused) beam profile, do you?

For any more specific comments/advice, I would really need to see the speck and artifact

Have fun with your laser

Peace,
dave

Now that I have the laser focused I cant see the speck, so that no longer matters. But, now that the lens is so far into the module, the focus ring only screws on a little bit. So I guess I'll just have to glue that on there or something.
Thanks for the help
-BlackWidow

I just removed the metal focus ring, I was having focusing issues with my laser too.