This is my final addendum to this review of the Dino 300 as-is ------
As noted above, I have added a larger lens to capture more power and it appears to have worked but with problems.
This picture shows the machined parts to hold the 10x10 mm lens from Edmonds. It was first built on centerline for the beam but DPSS lasers aren't always centered so It was made adjustable.
Focus adjustment is 9/16 x 18 NF threads.
I assembeled the parts into the head and adjusted for the best beam exit characteristics. The machined parts are glued into place with UV cure adhesive.
Now for the optics part -----
Without a focusing lens, the output has a large rectangular beam with an unusual dancing effect. This indicates mode hopping but lenses won't show a TEM mode.
The problem arises when I try to gather this beam with a large lens, it has a flare at a 45 degree angle which I can't eliminate.
While this gives poor beam characteristics, it has added a few mW to the power. This isn't good for the projo types but still throws a fat beam.
Power output can be unstable because of the hopping but these two graphs show an increased power compared to the original ~6mm lens.
Above spec power but useful for "pointing".
This was an attempt to control a "wild" beam. The dancing output may indicate an overdriven laser but it sure is bright... I will make one more attempt using a 9mm assembly in this laser. Then-- major surgery!
HMike
1/24/11 -- I made a new holder today for a standard 9mm Aixiz style lens assembly. I got a much better beam but limited to only ~ 200 mW as the small apperature clipped the large raw beam.
1/26/11 -- I took this laser appart and found a somewhat unique driver with a thermistor temp feedback. This is used on a + rail ground host too!! I will be analyzing the driver as time permits. I see this post dropping into the dumper. If you want to comment, use my email.
1/30/11 --- The + rail driver in this laser does not seem to regulate anything. It acts mostly like a basic resistor. Voltage input appears to adjust both LD voltage and current without limit. I can't believe that the IR pump diode still lives with 3.5 applied volts. Thinking that it is a PWM driver, I connected my OScope and I see no switching pulses.
The feedback resistor is 0.10 Ohms. By changing it to 0.75 Ohms, I seem to be getting control of the circuit and it's regulating. A quick test of the thermistor appears to show it as a foldback protector which might be nice in a portable. I'm looking for a small 0.30 Ohm to try in this since my target current is ~1.1 Amps.
2/1/2011 --- After some testing, I find that the original sense resistor works good. The pot adjusts the current well at the 1.2 amp range and the thermistor when warmed too much kills the current. It's not immediately stable but I believe suitable for my RED build. I'm now making the Cmount assembly to mate with this driver allowing plenty of room for optics as may be needed.
2/4/2011 --- I have machined the Cmount assembly for the red diode. It will mount to the original Dino driver and screw into the rear housing. This provides good electrical contact which has plagued previous designs.
In the pictures below, the housing parts are in the center. The + rail driver and the green module are above. Below are the new parts to hold the 635 red Cmount LD and the tube which will provide mounting for optics as needed once I have photons!
The Dino housing and + rail driver is worth the money to me!
so it really has some potential!
