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OK, thanks for that. Yes, I typically use those singlemode open can diodes which are doing ~380mw if memory serves. The erasing works on the strontium paint, but it is painfully slow and very visible, of course. This kinda takes away “the magic” of erasing which is why I was thinking that lots of LED red worked into a show might be less obvious. The only other option I can think of is patience. ;)
-David
Well, if you wanted more of a "wash" for an eraser, then a couple watts of 650 nm red might do the trick... Thinking about a wide beam (perhaps even de-focused a bit to make for an even wider spot on the wall) that could be scanned back and fourth quickly in a raster pattern yet would still erase quickly due to the higher power.
True, a super-bright LED that lit up the whole wall at once would probably also work, but I think it would need to be so bright as to be very distracting in an otherwise darkened room. For sure it would be bright enough to leave an after-image for several seconds on the dark-adapted eyes of your audience.
Adam
That makes sense. I like the thought of erasing with some artistic rasters without being obvious about it’s primary purpose. I may just have to steal that idea. 😀
I made a deep-red LED flood a long time ago. I'll bring it if I can find it. Might as well educate our intuitions; I thought red didn't affect night vision.
Oh, that would be awesome if you can find it, Dan. I understand the same about the night vision, but the contrast of dim glow versus bright red can still be distracting depending on how it is incorporated into a show.Quote:
Originally Posted by DanBarlow
David
808nm might work and be so deep you can barely see it. just need a lot of it very rapid raster would let you put a lot of power in a small space in a short time frame. might just look like a quick flash
Good idea, but sadly I tried 780nm and 808nm on the strontium stuff and it had negligible erasing effects. The 808nm or maybe 850nm actually charged it up a bit. Interestingly, the warmth from your hands can charge it too. I discovered that accidentally when picking up the panels from outside in the dark when it was near freezing outside.Quote:
Originally Posted by kecked
The 780nm single modes on the zinc sulfide stuff worked really well - better than 808nm as I recall, but as I mentioned earlier zinc sulfide fades so fast, it isn't worth the effort IMO.
I'd be happy to have someone retry and confirm or rebuke my findings.
-David
How about a brush with the light in a bar that sweeps down the screen or across the beam and erases. Now the light is hidden. The bar can park at the bottom or top or side. You might even do it like a curtain between displays.
Ahhhh
How about making a beam that follows the display beam just slightly back the other beam but not enough so you need a second set of scanners. You can modulate the eraser as needed. Now since the energy is packed as small as you can, you need less intensity to do the job and you automatically follow a distance behind or in front of the main activation beam. Shame you can't use IR Other nice thing is you can partially erase or turn a line into dashes or such.
Now that's a damn good idea! (You have a lot of those.) I have a remote control screen that I could convert to DMX and mount a bar of deep red and let the screen drop and return with the light on whenever I want to erase. The bar would be hidden behind the screen so it wouldn't screw up the aesthetics of the room.Quote:
Originally Posted by kecked
I'm not sure I fully understand that idea, but the 405nm beams are analog modulated, so drawing dashed lines or dimmer sections aren't an issue. You'll have to explain this more later in the week in person.Quote:
How about making a beam that follows the display beam just slightly back the other beam but not enough so you need a second set of scanners. You can modulate the eraser as needed. Now since the energy is packed as small as you can, you need less intensity to do the job and you automatically follow a distance behind or in front of the main activation beam. Shame you can't use IR Other nice thing is you can partially erase or turn a line into dashes or such.
-David
David,
Wow... speechless. Well done.
Greg