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LEP - Light Emitting Plasma — Parallax Forums

LEP - Light Emitting Plasma

Beau SchwabeBeau Schwabe Posts: 6,566
edited 2013-07-06 17:19 in General Discussion
This is really interesting to me, why haven't I heard more about this? Does anyone have an idea on the RF circuitry for something like this?

http://www.youtube.com/watch?v=rQU7a1zMkhg

http://www.youtube.com/watch?v=VOSXKIlDC6o

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-07-05 22:45
    Those look really neat for indoor lighting. There must be some intensely-focused RF happening to make the argon incandesce like that!

    LEP lamps would be the bane of Dark Skies for outdoor lighting, though. In this neck of the woods, metal halide, high-pressure sodium, and mercury vapor have given way to down-directed low-pressure sodium for outdoor use. Despite it's weird color rendering, it's made a huge difference in the area's overall livability at night. Glare is significantly reduced, and you can actually see stars in town when the sky is clear.

    -Phil
  • W9GFOW9GFO Posts: 4,010
    edited 2013-07-05 22:58
    Phil Pilgrim (PhiPi) wrote: »
    LEP lamps would be the bane of Dark Skies for outdoor lighting, ...

    I don't see why. As long as the light is directed where it is useful the skies should not suffer.

    Every time I think about street lighting I wonder how much money would be saved by using fixtures that did not waste light by casting it upwards and sideways.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-07-06 09:10
    Here's an article on why astronomers prefer low-pressure sodium outdoor lighting:

    -Phil
  • kwinnkwinn Posts: 8,697
    edited 2013-07-06 09:41
    Old technology. Take a look at http://en.wikipedia.org/wiki/Inductively_coupled_plasma.

    What I am wondering is how they are keeping the bulb from melting. In the ICP quartz torch there was a flow of cooling argon gas around the perimeter of the torch to keep the quartz tube from melting.
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-07-06 11:21
    kwinn,

    I agree, the technology is old.... I remember as a kid putting NEON bulbs on the top of CB antennas so they would light up as you transmitted.

    ...and the article you point to uses a magnetic induction method to transfer energy, but I think the LEP method differs in that it uses RF similar to the NEON-CB antenna I referenced. I'm just wondering what the specific circuit might look like that can deliver that much concentrated RF to cause something the size of a pencil eraser to light up an entier room as if you were outside on a bright sunny day. Seems to be leaps and bounds orders of magnitude over what I though was previously possible without having some sort of RF radiation issues with other nearby objects.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-07-06 11:37
    Beau,

    I saw a Wikipedia article that suggested that microwaves are used and that the ceramic puck acts as a dialectric waveguide or "lens" of sorts to concentrate the RF energy.

    Here's the article: http://en.wikipedia.org/wiki/Plasma_lamp

    -Phil
  • kwinnkwinn Posts: 8,697
    edited 2013-07-06 12:54
    Beau,

    The ICP does use a coil (typically 3 or 4 turns) and capacitors in a resonant circuit to produce a high intensity electromagnetic field in the center of the argon stream to produce the plasma. Most of the equipment I worked on used 27 MHz at 650 or 1200 watts, although there were some that operated in the 40 Mhz range.

    The plasma temperature was in the 6000 degree Kelvin range, and produced quite a bit of UV, and since these bulbs run at the same temperature I was wondering how they dealt with the heat and UV problems. While the bulb may be quite small I have a feeling the additional parts to make it work will add quite a bit of bulk to a complete system.

    Phil,

    Yep, read the same article. Curious to see what the entire LEP lighting system looks like and how much the entire system efficiency is.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-07-06 14:59
    Is this the same technology as
    http://en.wikipedia.org/wiki/Electrodeless_plasma_thruster
    or
    http://www.kickstarter.com/projects/2027072188/plasma-jet-electric-thrusters-for-spacecraft
  • kwinnkwinn Posts: 8,697
    edited 2013-07-06 17:19
    The "inductive discharge" part of "applying an alternating electric field either via a capacitive discharge or an inductive discharge" sounds similar to what is done in an ICP. Of course producing an ionized plasma is only part of a plasma thruster. The ionized gas must then be accelerated to a high velocity to produce thrust. I wonder if the same technology that was used in the cyclotrons would produce a high enough exhaust velocity.
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