445 experiments

[krazer]

Has anyone been able to figure out the strip width on one of these diodes?

I remember reading somewhere that it is possible to calculate based on the divergence of the raw diode, but I can't find out where I read that. If push comes to shove I can put it under the SEM at work in about a month.

On that note, has anyone been able to measure the current inside the projector? I am dying, there are pictures of a scope capture and a series resistor in series with the diode, but the last few calculations to find the peak current are missing

While I am asking, has anyone measured the fast/slow divergence when you use the stock lens? From what I can tell it looks like those lenses are of fairly poor quality (lots of side lobes and stuff), but it would still be a decent baseline measurement.

Thanks!

[andyf97]

Has anyone been able to figure out the strip width on one of these diodes?

I remember reading somewhere that it is possible to calculate based on the divergence of the raw diode, but I can't find out where I read that. If push comes to shove I can put it under the SEM at work in about a month.

On that note, has anyone been able to measure the current inside the projector? I am dying, there are pictures of a scope capture and a series resistor in series with the diode, but the last few calculations to find the peak current are missing

While I am asking, has anyone measured the fast/slow divergence when you use the stock lens? From what I can tell it looks like those lenses are of fairly poor quality (lots of side lobes and stuff), but it would still be a decent baseline measurement.

Thanks!

All data will come soon, its a bit new yet for such technical stuff.

[stanwax]

On that note, has anyone been able to measure the current inside the projector? I am dying, there are pictures of a scope capture and a series resistor in series with the diode, but the last few calculations to find the peak current are missing

no scope captures of current im afraid
Rob

[kecked]

Anybody measure the beam size a few inches away and say 5-10 feet away? just curious if the beam will fit on scanners. If it is small enought a 2x or 3x collimator might tame the beam. who cares if you loss 50% of a 500mw diode when you only need 150mw of power.

[jayrob]

I took some measurements using an AixiZ 405 glass lens...

Wearing eye protection, you can see that the AixiZ 405 glass lens still produces a line, not a dot. But pointing out into the night sky, and just normal pointing like we do normally, it looks pretty good for a cheap way to collimate this diode.

I measured the 'dot/line' at 20' best focus. At this focus, I measured the dot/line at 20', and also at 2" distance...

* 2": 2.3mm X 5.4mm
* 20': 2.2mm X 16mm

See lens comparisons, and dot pictures of three different glass lenses (including the stock projector lens) here:
http://laserpointerforums.com/f65/44...ons-51456.html

[allthatwhichis]

Can anyone post a list of the differences between the Casio diode and the Nichia diode?

[dave]

^^^ Pretty much just bigger emitter... I think.. The rest of the specs seem extremely similar in terms of current, threshold and slope efficiency.... ll have our rgb that has a 1w diodes that came from Nichia out for a few shows next weekend, so Ill do some comparisons whilst I'm at it..

[stanwax]

just to add more fule to the argument about the duty cycle and how it works here is an image of the phozzie wheel with the angles shown. The phosphor is coated on a 300 degree segment - in the gap is a 60 degree diffused window. The other window is 130 degrees and also diffused and the centre of these two windows is 180 degrees away from each other.

Rob

[krazer]

Scope traces don't lie, either a portion of the phosphor isn't used (keep in mind the red has a separate beam path-so its timing is independent of the blue/green) or much longer pulse times are needed for the red/green than the blue.

Assuming the full area of phosphor is used the duty cycle breakdown is roughly
red - 50%
green - 42%
blue - 8.3%
IE- the disk makes 2 revolutions per scan, one 'dummy' rotation when the red is on, then one which gives green/blue

But since I believe the phosphor is more efficient than that, I propose that the disk actually turns once per frame, and some phosphor is unused. Then the duty cycle would work out to be
red - 50%
green - 34%
blue - 16%
which seems a bit more reasonable...

I also am 90% sure that the 60 degrees portion of the disk is just there to balance out the weight distribution, since I do not see any way for light to make it through there....


In any case, the updates earlier in the thread have been updated, and it does look like the diodes are being blasted with 1.4A at as high as a 66% duty cycle, which means the diodes are being run at significantly over a watt (closer to 1.5w).

I wonder who the first person to drive one of these to destruction will be, I suspect it will do significantly over 2w before it turns into a LED.

[stanwax]

Krazer
I am just buildin a little rig to play with one and I intend to kill one at some point (prob. sooner than later ) My intention is to kill one not to kill accidentally - we will see what happens first!
Rob