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Which Green Diode ?

badboybilly

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What you are calling an artifact in the beam sot looks like something it your optical path. I'd check the diode window carefully. Also, look for anything out of place between the diode window and the lens. That rectangle should not be there and there is a reason for it. Just need to find what that reason is. It is also possible there is a reflection is the module that shouldn't be there.
Really Paul that rectangle shouldn't be there, most high power diodes have that rectangle when using a G2!
 
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paul1598419

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You are confused, Billy. Look at the second photo again. The one you used from the OP's photo. It has a focused spot and to the left there is a remnant that should not be there. Your other photos mean nothing when compared to this one. Of course an unfocused beam will give you the rectangle you describe, but this is not in anyway THAT. If you can't see that, I can't help in any other way.

Edit: noticed you changed the post completely, leaving out the photos and the explanation that the rectangle is a normal result of the diode's emitter. Now it is changed to the G-2 is the problem. Very handy now that the true problem is known.
 
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Mosc007

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It does seem like a reflection somewhere. I will see if I can find anything.

I will check DTR's site. Thought he only had 3 element and the G2.

Update. Just ordered a couple of 2 element 520 from DTR. Never noticed them before.
 
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paul1598419

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Which lens did you get with this again? I hope you didn't opt for the no lens option as that one is acrylic and will cause you no end of problems with this diode.
 

Mosc007

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Which lens did you get with this again? I hope you didn't opt for the no lens option as that one is acrylic and will cause you no end of problems with this diode.

I ordered it with a G2. Very unlikely I would get 1125 mw with acrylic.
 
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paul1598419

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Just for Sh@ts and grins look closely at that lens. Make sure it doesn't have any debris on it. You can look at a light with it and see better. Next, I'd look at the diode's window. Something is not right, just don't know what.
 

Mosc007

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I just swapped the lens for another G2 I have here. Exactly the same reflection. I looked at the window in the diode and as far as I can tell it's clean.

The reflection kinda looks like light reflected off the front of the diode mount. I can see the front of the diode mount in the window.

I will see what it looks like with the 2 element 520 when it arrives. It's not a big problem. Just shouldn't be there. I am sure I recall it being posted here before. Consensus was the G2 causes it.
 
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badboybilly

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Not all cameras take photos the same, it looks normal to me, it's reflected off of a shiny black tv what about a better photo on the wall!
 

Mosc007

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Not all cameras take photos the same, it looks normal to me, it's reflected off of a shiny black tv what about a better photo on the wall!

It's to bright to take a photo on anything other than black. That's not a shiny black tv. It's a 90 inch projector screen. That is black velvet it's pointed at.

To the eyes it looks the same on a wall. Bright spot with rectangle off to one side of the spot. The rectangle is only a fraction of the brightness of the main spot. Hard to take a photo cause the focused spot is so bright.
 
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Mosc007

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Just had a quick check with a 3 element glass. The reflection is gone. Didn't bother checking power. I know it will be a lot lower.

Anyway, I am almost certain the G2 is reflecting light back into the window. It then hits the front of the diode mount and reflected back out as a low power rectangle on one side of the main spot.

I will check power when the 2 element 520 arrives.
 
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CurtisOliver

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Yes, I have seen those reflection before on my own lasers with a G2 lens. It is definitely the lens.
 

Mosc007

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Yes, I have seen those reflection before on my own lasers with a G2 lens. It is definitely the lens.
I had seen it posted before. Very noticeable on the 7475. Probably the way the diode is mounted internal.

It's reflecting off the front of the heatsink the diode is mounted on. You can see it looking into diode with magnifying glass.
 
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paul1598419

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It might be the AR coating on those lenses. I think there were AR coated for violet/blue. Not sure, though.
 

dden4012

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My NDG7475 arrived from DTR. Assembled it in a S4 Host. Using 2 18340 Lion Cells.

I modded the host slightly to give better heatsinking. These Green diodes produce a lot of heat for a small output. 1 Watt output and 9 watts of heat.

I bought the diode and driver mounted in one of DTR's 20mm modules. I purchased the S4 and the 20mm Adapter to suite DTR's module. What I did was use thermal adhesive and bonded the supplied 12mm adapter to the back of his 20mm module. Then I used the original 12mm mounting and the 20mm mounting. I drilled and tapped a 2mm Grub screw in the end of the outer ring to secure the 20mm module in place. It ends up about 25mm longer than standard. You can see in the picture.

I had read on here before about artifacts with the NDG7475 diode. I think it was related to the G2 lens ?. I took the photo with it aimed on a very black velvet area on my projector screen to stop the spot saturating.

It focuses to a nice bright spot. But it has a larger rectangle on one side of the spot. The Beam measures 1125 mw on my Hyperion.

I might try a 3 element lens and see if the artifact is gone.
That's the G2 shadow. I get that with greens and blues. SM and MM.

If you only get 1w from a better lens I won't judge you. I understand.
 
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