pencil lead thin 445nm beam-no prisms no cylinderical lens

[kecked]

I got some 2x beam expaders and placed one after the glass collimator of my 445nm diode. My beam is now focusable to a fine dot in my room and up to about 30 feet away. You loose some of the beam off the scanner but when you got 1 watt and only need 500mw this is a clean straight forward way to correct the beam. The beam now matches my red open can diodes perfectly. You can even dial it in to be larger or smaller. Just thought I'd share the effort. You can buy the expanders from www.meshtel.com for $50.00. I glued it to the colimator adjustment ring. PS works for dpss lasers as well.

I added a picture. This was at about 20 feet from the projector. I had to run really low power to take the picture.

[swamidog]

got pics?


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BELA LUGOSI is my co-pilot..

I got some 2x beam expaders and placed one after the glass collimator of my 445nm diode. My beam is now focusable to a fine dot in my room and up to about 30 feet away. You loose some of the beam off the scanner but when you got 1 watt and only need 500mw this is a clean straight forward way to correct the beam. The beam now matches my red open can diodes perfectly. You can even dial it in to be larger or smaller. Just thought I'd share the effort. You can buy the expanders from www.meshtel.com for $50.00. I glued it to the colimator adjustment ring. PS works for dpss lasers as well.

[Xer0]

Sounds to easy to be true oO how does it correct fast/slow Axis??

[kecked]

Sounds to easy to be true oO how does it correct fast/slow Axis??[/QUOTE]

No idea why it works but it does! Try it.

PS: at 100 feet the beam is about 1 inch so it is only useful for graphics in a small space. So this will be best for us home users. The beam is actually tighter than my argon was with the same beam expander on it. This is an old trick I read out of a book by L. Micheal years ago and tried out. The book is way out of print but has some good but dated ideas.

[allthatwhichis]

So technically you still need to correct the big D on one axis before the teley.

[kecked]

All I did is put a normal axisiz red collimator (suprize they are only ar coated nothing special) in the housing and glue the expander to the front of that. No correction of any kind. I guess what I am doing is focusing the lens on the wall cuz after that point if you aim it out the window it starts to diverge again.

[allthatwhichis]

1 inch at 100 feet is about 2x smaller than what my Kvant's is; 1inch at 50 feet. I will assume the "small" side is 1/4 inch at 100 feet? The reason everyone is trying a prism or cylinder lense is to get it the same 1/4 inch by 1/4 at 100 feet... or somethign similar. I'd be happy with that.

You are right though, my projector looks great at 10 feet. I try not to use it for graphics past 30 or so feet.

[dar303]

Maybe it has clipped/masked the beam? Measure the output power and the current you run it at to see.

[kecked]

Oh I'm definitely loosing lots of power. I just don't care since I have more than twice what I want. If your after power look to the other methods. I just thought I'd share a simple way to get he job done for those of us at home at a watt or under.

I just switched to 642nm red. Kind of intersting color pallett. Need to mix back in my 660's to deepen it a bit to 650ish color. MUCH brighter thou. Nowe I need more green. My 100mw doesn't cut it anymore.

[mccarrot]

The aixis lens is a high FL lens, this normally will give you a 5x2mm beam with a divergence of 1,6mRad

If you shoot it trough a 2X beam expander you will get a 10x2mm beam with 0,8 mrad
or you turn it arround and get a 2,5x1mm beam with a divergence of 3,2mRad

In my opinion a useless solution, if you just took a aspheric lens with a lower FL you would get the same results only with less optics and less losses.

Correct me if i'm wrong.