DLP and RGV laser projector

[Stoney3K]

Your going to be as much as 30-40% down on the green at those mod rates, without retuning the laser's PID or going AO or mechanical modulation.

The 'modulation' is nothing more than a repetitive signal which requires no external control. No need to use an AOM, a spinning wheel with a butterfly shutter is more than enough.

The DVD and BR's will happily modulate at that speed, so you don't need to do anything special there.

You will lose a lot of green power because it's outputting at such a low duty cycle, but that's seriously hard to avoid. I've been experimenting with overdriving a green when it's running on lower duty cycles, but it's quite a trade-off between risking COD and losing output power.

[buffo]

In 2008 (on the ILDA cruise) I met a guy who was working on a series of lasers to be used by Mitsubishi for their new Laser TV. The TV was based on DLP technology, but they were replacing the light source and spinning mirror with three solid-state lasers. This sounds exactly like your project.

For the record, the blue laser they were using put out 3 WATTS of power. Now, this was a unique laser in that the beam divergence was amazingly awful - on the order of 15-20 DEGREES (not mrad!). But it was also a very small laser. If you took the huge heat sink off, the head itself was a cube no bigger than 1 inch on each side.

The problem they were having was with the red laser. They could only get up to around a watt with the unit they were using, and for form-factor reasons they didn't want to change to anything else. I never did find out how they solved the problem, but Mitsubishi is supposedly selling these TV's in Japan right now.

Adam

[kingbowser]

ok, thank you

now that the laser hypothesis has been rejected, what do you think of the combination of these three LEDs?
http://cgi.ebay.it/ws/eBayISAPI.dll?...m=360237378187
http://cgi.ebay.it/ws/eBayISAPI.dll?...m=360238147342
http://cgi.ebay.it/ws/eBayISAPI.dll?...m=360237388006

the same vendor sells even 6000 lumens (100W) version! 120$ each
what do you think of a 18000 lumens projector?

[tocket]

I think that vendor is pulling those luminous powers out of his ass. There is no way that a blue 20W LED gives 1000 lumen.

[kingbowser]

there are only 50 lumen per watt, it isn't a great efficiency...

for example cree makes LEDs which are 150∼200 lm/W

EDIT: Sorry, I didn't read the word "blue". You're right, surely blue won't be so powerful.

[tocket]

Yes, it might be true for the green and even the red. Blue has a much lower luminous efficiency though. At 470 nm it's about 62 lm/W (that's W in radiant power). Assuming a current-to-light conversion efficiency of 25% that LED will make 5W of light at 20W, which corresponds to about 300 lm.