- Joined
- May 15, 2012
- Messages
- 320
- Points
- 28
Hey there. I decided to put together a 2W laser since I had never witnessed 2W before. I got a C6 host with a copper heatsink and 1.86A driver from Survival Laser and an M140 from DTR. Spent a couple hours putting it together. I turned it on and I didn't notice it being much brighter than my 1150mw Osram PLT450B C6 (from across the house). The neat thing about it was that this M140 appeared much bluer than the Osram 450nm PLT450B; what I can show you is subjectively what I witnessed as (R,G,B):
the Osram LD being (80,0,255) and the M140 being (0,70,255). Keep in mind, that this is not science and I'm not saying that the Osram is 426nm, it's just how it appears to me compared to the M140: Wavelength RGB Calculator. In this image, the Osram is on the left and the M140 on the right. The M140 appears to have a much rounder beam shape than the Osram. That's just how they are. These are their beams expanded by their lenses, not raw outputs.
So I metered it at about 1300mW. Now, that's through a DTR 3 element glass lens. Baffled, I removed the lens to go ahead and meter it directly from the diode and pffffft *fart noise* oh nos! It LED'd and I got kinda sad :c
Specifics
1: I'll admit I was using a brass collimator module instead of copper. Assuming copper's thermal conductivity k is 401W/m*k and k(brass)=109W/m*k, and since the equation for 1-dimensional heat transfer is a function of (k)^1 [q=kAdT/dx], I will assume that the heat on the die was building up almost 4x as fast as if I were using a copper collimator module.
2: About 10 seconds into its runtime, the driver started making a strange whining and clicking noise, then it stopped making noise, and then the LD died.
Prognosis: I cooked it up real good.
But still, this was an incredibly inefficient M140. From DTR's power tests, I should have been getting at least 1950mW=2300mW-(2300mW*0.15) accounting for losses in the 3-element lens. Assuming the same forward voltage as DTR's M140, my LD was only 19% efficient where it should have been 28% efficient, and was producing 6.9 watts of heat instead of the ideal 5.9 watts of heat. I guess I just got the one sadly flawed LD out of the bunch of them. And it really wasn't an accidental mixup; here's the mark signifying a genuine M140:
Just overall some interesting stuff that I found fascinating.
the Osram LD being (80,0,255) and the M140 being (0,70,255). Keep in mind, that this is not science and I'm not saying that the Osram is 426nm, it's just how it appears to me compared to the M140: Wavelength RGB Calculator. In this image, the Osram is on the left and the M140 on the right. The M140 appears to have a much rounder beam shape than the Osram. That's just how they are. These are their beams expanded by their lenses, not raw outputs.
So I metered it at about 1300mW. Now, that's through a DTR 3 element glass lens. Baffled, I removed the lens to go ahead and meter it directly from the diode and pffffft *fart noise* oh nos! It LED'd and I got kinda sad :c
Specifics
1: I'll admit I was using a brass collimator module instead of copper. Assuming copper's thermal conductivity k is 401W/m*k and k(brass)=109W/m*k, and since the equation for 1-dimensional heat transfer is a function of (k)^1 [q=kAdT/dx], I will assume that the heat on the die was building up almost 4x as fast as if I were using a copper collimator module.
2: About 10 seconds into its runtime, the driver started making a strange whining and clicking noise, then it stopped making noise, and then the LD died.
Prognosis: I cooked it up real good.
But still, this was an incredibly inefficient M140. From DTR's power tests, I should have been getting at least 1950mW=2300mW-(2300mW*0.15) accounting for losses in the 3-element lens. Assuming the same forward voltage as DTR's M140, my LD was only 19% efficient where it should have been 28% efficient, and was producing 6.9 watts of heat instead of the ideal 5.9 watts of heat. I guess I just got the one sadly flawed LD out of the bunch of them. And it really wasn't an accidental mixup; here's the mark signifying a genuine M140:
Just overall some interesting stuff that I found fascinating.
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