New lighting technology - any hope?

[Skogsgurra]

What do you think about this:

http://www.lightlab.se/en.aspx

I have been following them for a while. They have taken over a field emission based lamp from Russia. The comapny started in 1996 and has shown one prototype in March 2013. There seems to be a problem with the high voltage generator (they use 6 - 12 kV to get the emission going) so they didn't let it burn for more than a few seconds. Light output was bluish-white and there was a lot of flicker.

Questions:
1. What will a realistic production cost for a 10 W, 6 kV DC supply be? Remember that millions of them will be built.
2. What is a realistic efficiency for such a device? I see commercial devices having around 60 percent efficiency.
3. What will the volume of such a high-voltage power supply be?
4. What EMI problems are likely to show?
5. What MTBF can one expect from such a device? Ozone and insulation degradation seems to be the dominant problem.
6. Compared to LED lamps - do you think that is is sound business to start production of an FEL lamp?
7. Is there a need for an FEL lamp?

Any views, insights, experiences welcome!

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[MacGyverS2000]

I think I could make a diode/cap voltage doubler type circuit for a few dollars... not saying it's practical from a space standpoint, but it would be relatively cheap. Pretty low EMI, too.

Your efficiency number of 60%... is that just the power supply or the entire unit, light and all?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Skogsgurra]

Power supply only.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[IRstuff]

Cold cathode field emission technology has been around a while. Their website seems to contain very outdated material/information, for a burgeoning technology. For example, LED luminous efficacy is reported to be on the order of 100 lm/W, which exceeds the 85 lm/W figure quoted on the website. Seems to me that there are a number of negatives for this technology:

> the electrons need a vacuum to emit, which then drives the need for a glass bulb configuration
> the emission electrodes must be physically "pointy" to increase the electric field for efficient emission, but since the bulb will have less than perfect vacuum, the residual gases combining with the energetic electronics may degrade electrodes
> the glass itself is a handling and disposal hazard
> the vacuum required is usually higher than that of a conventional incandescent bulb, resulting in even thicker glass than for an incandescent bulb.

I'd guess that there are operational issues as well. Almost any STEM student has had a high school or college physics problem to calculate the drop of an electron beam in the presence of gravity. Because of the electrodes' electric field enhancement through electrode shape, less actual field is required to emit the electrons, so they're be travelling slower, hence, be more affected by gravity. I'd guess that there'll be a dark spot on the apex of the bulb in the up orientation, and a hot spot when in the down orientation. Additionally, the need for an anode on glass presents a unique problem, since it needs to be both conductive AND transmissive, which are typically mutually exclusive. This will cause some orientational problems as well.

btw. the quoted 85 lm/W is essentially about 11% plug efficiency, so it's not a major efficiency breakthrough. The

http://www.lightlab.se/en/technology/comparisons_with_existing_technology.aspx

page does not report any efficiency value newer than 2011, which is the same efficiency that they say was achieved in 2009. This implies that they've either run into money problems or technological problems.


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[MikeHalloran]

I see anything volume- related as similar to fluorescent or CFL technology.

Claims of enhanced reliability/ long lifetime are pure BS. Anything with a high voltage is going to be life-limited, absent some new breakthrough in insulation technology.

The only substantial virtue is the absence of mercury, and that's more of a political virtue than a practical one.

IMHO, the business only makes sense if they can get a government to mandate purchase of the product.


Mike Halloran
Pembroke Pines, FL, USA

 

[btrueblood]

These guys are doing similar product.

http://www.vu1corporation.com/

They are a bit further along, though they stumbled at getting a production line going. I think their biggest problems were in the repeatability of coating phophor(?) on the inside of the glass. Suposedly, they will be shipping product this month, though I see no signs of that happening.

 

[IRstuff]

"Anything with a high voltage is going to be life-limited"

I don't think that it's that high a voltage. The field concentration from electrode design is what keeps the power down; otherwise, you'd need kV power supplies, which aren't needed here. However, by the same token, the field concentration around the electrode means that the electrode is more susceptible to degradation effects.

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[Skogsgurra]

The voltage is between 6 and 10 kV. I think that is the biggest problem they have to find a solution to.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[IRstuff]

Oh, that's absurdly high, and that probably means they're fubar.

With 85 lm/W, 1000 lm should require 11.8W and a cathode current of 443mA, which means that the acceleration voltage needs to be less than 26.5V

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[IRstuff]

Oh, sorry, I didn't thoroughly read your OP.
1. What will a realistic production cost for a 10 W, 6 kV DC supply be? Remember that millions of them will be built.

I think it'll be too expensive for anything less than an array of bulbs. To be a viable system, the power supply needs to be contained within the bulb, just like they are in LED bulbs. To have an external component is going to be a royal PITA.

5. What MTBF can one expect from such a device? Ozone and insulation degradation seems to be the dominant problem.

While broadly lumpable in "insulation degration", running the power supply semiconductors at high voltage stresses internal structures within the semiconductors. I think that the current draw requirements are going to be too high, which will further degrade reliability through joule heating. Electrode degradation, I think, is a real possibility; this would be similar to electromigration in semiconductor aluminum metallizations. High current densities result in sufficient momentum transfer between the electrons and the material atomic structure to move the atoms downstream, and evenually create an open circuit.

6. Compared to LED lamps - do you think that is is sound business to start production of an FEL lamp?

I don't think there's anything inherently wrong with FEL technology. But, it needs to be running a much lower voltage to make practical sense. One major issue that I would see is that the consumption of phosphor material is probably 10 times as much as the equivalent intensity LED lighting. In a white LED, the phosphor coats the LED die itself and a chunk of the surrounding area as well; it's not area efficient, but it's more efficient than, say, coating the outside of the clear plastic housing. The LightLab phosphor coating is covering the inside of the glass bulb, so is areal efficiency relative to a comparable LED lamp will be very poor. Glass has its inherent handling issues, compared to the plastic of LEDs, so there will always be some additional attrition during shipping damage.

7. Is there a need for an FEL lamp?

Possibly. It could be arguable that technology required to build an FEL lamp is less than that of an LED, and possibly uses less toxic and hazardous materials nad less exotic materials. Indium, gallium, arsenic antimony, etc., are typical elements required for light emitting semiconductor sources. This coupled with a slew of noxious processing chemicals used to make the LED.


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[racookpe1978]

Hmmmn.

Watt if they try for a different market?

That is, try to replace the very-high lumen, very-high wattage (stadium light or street light or floodlight market or advertising sign or entertainment market) rather than the household/office low-watt/low lumen market?

 

[jmbelectrical]

85 lumens per watt? That's nothing! As of February of this year, Cree successfully produced an LED with an efficacy of over 270 lumens per watt.

racookpe1978: You do bring up a great point about going after a different market. Most sportslighting projects that I encounter still incorporate 1,000W or 1,500W metal halide lamps. And lots of them.