Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[planters]

Still working on spatial filtering. This is probably going to work pretty well.

However, in the mean time I have uncovered another wrinkle, maybe a good one. Aligning the diode axis well with the cylinder optics is very difficult. The diode mount I am using from LSP allows the diode to be positioned so that it is centered on the collimator. This works well and produces a more symmetrical central far field spot, but the rotation of the diode in its countersink is pretty much hit or miss (mostly miss). With the rectangular correction optics it is easiest to mount them with the expansion axis strictly parallel with the floor. If the diode is rotated even a few degrees from level the effect on the far field spot is to noticeably increase the vertical dimension of the spot. To visualize what I mean imagine if you compressed \ horizontally vs _ The problem can't be corrected by adjusting the lenses in rotation unless all the diodes were "off" by exactly the same amount and in the same direction.

The best solution is to set the diodes as perfectly parallel as possible. I am considering using a VERY small set screw in the side of the back retention plate, so that once the diode has been installed as close to good as possible then the set screw is tightened and the final tweak is performed along with the X/Y shifting operation.

The reason I think this might be good is that when the lenses are optimized for the rotation of a single diode and the near field spot is 2mm x 4mm the spot I get at 13M is 12mm x 25 mm. This is 1/2 as high as I was expecting.

[Stoney3K]

5) Survival of the mask at high power levels
6) A compact and easily fabricated mask/lens assembly.

I am no where near the video phase, but I am thinking a lot about this. Any ideas?

How about first telescopically expanding the beam to something about 1/2" to an inch wide, masking it (making it easier to align the mask and easier to make a mask that will live through high powers) and subsequently compressing it to your desired beam diameter afterwards? If you use the same telescope arrangement on either side, there should be no difference in divergence.

You could even try using a photographic aperture linked to a servo through ILDA (beam brush), so you can select a low power, razor thin beam for graphics and go all the way wide open when you want to do beams.

I fail to see why we're working with millimeter-thin collimated beams in the optics path of our projectors anyway. The only place where that's useful is on the scanner mirrors and out the aperture -- when you're working inside the projector, big beams are a lot easier to align and give you more control over convergence.

[planters]

That's what I too thought at first, but the reason spatial filters have a long legacy of micro dimensions is that they have traditionally been used with gas lasers with relatively small diameter beams and the filtering effectiveness is related to the ratio of the input beam diameter to the diameter of the focal spot. Filtering at the 99.9% level is typical. The process is exciting because the effect is much more elegant than simply masking the peripheral energy. Much of the high frequency (read Fourier) noise such as dust ripples, lens scatter and multi-mode stripes are also removed and so the filter should be placed as far along in the beam line as is practical. This makes a lot of post filtering beam manipulation less attractive. However, that being said I agree that the demanding precision of a typical filter is unnecessary. If I can successfully remove 90% of the far field noise then I'm way ahead of the state of the art and this is easy. It is so easy that I can hold the aperture for a short time FREE HAND and the result is impressive.

[f150trk21]

Andyf97

Did you ever to the test like you did with the 71?

thanks

[andyf97]

Andyf97

Did you ever to the test like you did with the 71?

thanks

Did not understand that.

[f150trk21]

I just love dr planters videos, they are very interesting to watch.

I too did a bit of something related that might be of interest with a G71 in 2011. I did this test to simply see at what temp the power is most steady, I did not record the current because I was only interested in finding a stable temperature vs power which turned out to be 25c 750mW. I am going to do the same for the P73 tonight which should exceed 1W at least for a moment.

Oh, i meant this test, but with the 73.

thanks

[andyf97]

Oh, i meant this test, but with the 73.

thanks

Its one of the 1000 things on my to do list. I do plan to try and kill P73 soon just a bit busy right now.

[steve-o]

At 100 bucks a pop I'd say that's way down on my to-do list too lol .

[planters]

I probably should do the ultimate power tests of the 9mm 445 and the P73. I suspect the numbers at -30C will make a few people giddy. But I don't plan to kill them.

[andyf97]

At 100 bucks a pop I'd say that's way down on my to-do list too lol .

I have one setup ready to be killed, just no time to give it a controlled condition firing squad yet )