how do you get air to show up a laser beam like this?

roid · Post by **roid** » Sat Nov 27, 2004 8:33 am

on the latest issue of zzzonline (205) is this articlea about a cool midair display that i just CAN'T FIGURE OUT:
http://www.zzz.com.ru/index.php?area=ar ... cle_id=176

can anyone figure it out?
the company is tight lipped about what it is actually doing to the air to make it display a laser projected ("projected" may or may not be the right word, since we don't know everything about it) image.

what i think it's doing is using a laminar airflow to keep a specially treated internal airflow steadily rising, and this is what they project an image onto with lasers. or perhaps the lasers are just exciting the air in some way momentarily, but the air coudl still be pretreated to ENABLE it to be excited, i don't know!

they say that they add nothing to the air, you don't ahve to refill it with anything, and you can run it in an airtight room forever and the room's finite air supply will not be changed, nothing added or anything. not even the temperature of the room will change (cept for the effects of running the electronics: some small heating).

what's got me stumped is:

"how do you enable normal AIR to reflect laser-light without changing it (permanently) or adding something to it?"

"or if the lasers are making the air flourese, how do you do that (with the constraints already mentioned)?"

there's movies, pictures, and a brief explanation of the technology (but not enough obviously

) on the article i linked, and links from it. naybe the movies will help (the map one looks particularly sweet).

help?

Mobius · Post by **Mobius** » Sat Nov 27, 2004 11:45 pm

If you froze the air, and ejected it in a very thin "plate" then the water vapour would actually turn to tiny ice crystals very temporarily - long enough to reflect laser light.

That's my guess anyway.

Samuel Dravis · Post by **Samuel Dravis** » Sun Nov 28, 2004 1:39 am

Mobius wrote:If you froze the air, and ejected it in a very thin "plate" then the water vapour would actually turn to tiny ice crystals very temporarily - long enough to reflect laser light.

That's my guess anyway.

That wouldn't work with very little humidity, would it?

Asrale · Post by **Asrale** » Sun Nov 28, 2004 2:31 am

That looks more like a fancy hologram than anything else, if you ask me...HOLY CRAP HOLOGRAMS WILL KICK ASS IN 10 MORE YEARS!!!

Xamindar · Post by **Xamindar** » Sun Nov 28, 2004 3:38 am

Asrale wrote:That looks more like a fancy hologram than anything else, if you ask me...HOLY CRAP HOLOGRAMS WILL KICK *** IN 10 MORE YEARS!!!

MMmmm, holographic Descent 4! mmMMMmmmmmmm......

MD-2389 · Post by **MD-2389** » Sun Nov 28, 2004 12:29 pm

Samuel Dravis wrote:
Mobius wrote:If you froze the air, and ejected it in a very thin "plate" then the water vapour would actually turn to tiny ice crystals very temporarily - long enough to reflect laser light.

That's my guess anyway.
That wouldn't work with very little humidity, would it?

It'd probably work better if they used something superchilled like liquid NO2 with a humidifier.

woodchip · Post by **woodchip** » Sun Nov 28, 2004 1:24 pm

Not freezing the air but cooling it enough that a thermocline is formed a set distance above the unit. So just as a thermocline in water can deflect sound and sonar, perhaps the device creates a denser layer of air to reflect the light displayed upon it.

Mobius · Post by **Mobius** » Sun Nov 28, 2004 9:30 pm

Even in very low humidity, there is still a LOT of water in the air. You'd "insulate" your super-chilled air with an "air-curtain" of semi-cooled air on both sides.

roid · Post by **roid** » Mon Nov 29, 2004 12:32 am

the device does not change the ambient room temperate anymore than running electronics does (slight heating). so if it were supercooling the air, it'd also need to be heating the air at the same time to preserve the ambient room temperature.

it doesn't humidify the air, unless it also DE-humidifys it to the same extent.

it doesn't use liquid nitrogen, since it doesn't require anything becides electricity to run.

my current theory is that: it is not using lasers for anything other than tracking movement, since the laser is only a IR laser. ie: the lasers are not used for the display, they just use a normal projector. and they are perhaps using cooled and heated air, mixed to create a fog with the ambient humidity of the room (the device's humidity working range is stated as 35%-95%. this is quite high).

Canuck · Post by **Canuck** » Mon Nov 29, 2004 2:19 am

Just seeing video 1 and judging from the fan noise (hey Helio display), the image is created from a vortex or swirling of air. Ingenious.

The image is being created from the vortex or disruption of air, even heat would cause an image to form but the tracking required would be much greater, the display technology is synched to the fan.

My TV would use Lasers and sharks.

Nuck out.

WarAdvocat · Post by **WarAdvocat** » Mon Nov 29, 2004 7:34 am

roid wrote:the device does not change the ambient room temperate anymore than running electronics does (slight heating). so if it were supercooling the air, it'd also need to be heating the air at the same time to preserve the ambient room temperature.

Yes, that accurately describes how an air-conditioning unit works. One end is cold, one is hot. If both ends are in the same room you have a net heat gain. All hail thermodynamics!

I'm voting for some sort of artificial vertical "thermocline", given that no fogging is visible above the unit.

roid · Post by **roid** » Mon Nov 29, 2004 11:19 am

oh yeah, oops.

i'm intruiged with this thermocline theory though, i had to look the word up. most info is talking about water though. can anyone here give a schooling?

Capm · Post by **Capm** » Mon Nov 29, 2004 9:37 pm

You guys ever seen the effect of heated air rising off pavement - its probably the same principle just refined and controlled.

roid · Post by **roid** » Thu Dec 02, 2004 8:10 am

but would that not rise the ambient air temperature?

WarAdvocat · Post by **WarAdvocat** » Thu Dec 02, 2004 8:20 am

I'm not sure if 'thermocline' is the correct term for what I was saying, but essentially what I meant was the creation of a vertical refractive region in the air, possibly by means of an artificially maintained temperature differential.

A similar atmospheric effect might be an inversion layer (LA Smog anyone?)