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End of an Era...




 
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Patrick J. / KD5OEI
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« Reply #100 on: October 12, 2010, 10:54:17 AM »

take this, all ye green pedagogues of CFLs and LEDs!

http://www.optoiq.com/index/photonics-technologies-applications/lfw-display/lfw-article-display/1878980169/articles/optoiq2/photonics-technologies/applications-__markets/energy-__environment/lighting-and_illumination/2010/8/lighting_-tailored.html

LIGHTING: Tailored emissivity paves way for 400 lm/W incandescent lamps

Aug 1, 2010

Just when you thought incandescent light bulbs were dead, researchers at Stanley Electric Corp. (Tsukuba, Japan), Osaka University (Osaka, Japan), Shizuoka University (Shizuoka, Japan), and the National Institute of Advanced Industrial Science and Technology (Tsukuba, Japan) have modified the blackbody radiation of an incandescent bulb, demonstrating the possibility of 95% electric power to visible-light conversion and paving the way for luminous efficiencies beyond 400 lm/W.1, 2

The inherent inefficiency of traditional incandescent lamps (only 2–5% of total input electrical power is converted to visible light, translating to low luminous efficiencies of 15–20 lm/W) has brought about their demise in favor of fluorescent lamps and LEDs. Unlike these modern sources, incandescent lamps require no external regulating equipment, are inexpensive to produce, and work on either alternating or direct current over a wide range of applied voltage values. Despite the failure of previous research to modify the blackbody radiation spectrum of an incandescent bulb (using expensive lithography and deposition techniques), the research team focused on selective-emitter design using tailored and less expensive thin-film coatings to improve efficiency.

High visible and low IR emissivity

Because visible radiation is typically 10% of the output from an incandescent bulb, with the remaining 90% being infrared (IR) radiation, an emitter should be designed with high visible emissivity and low IR emissivity. Using Kirchhoff's law, modeling shows that a material with high reflectance in the IR wavelength region and low reflectance in the visible region displays a reverse trend in emissivity. By imposing a step-function-like reflectivity onto the surface of the heating material, IR radiation is reduced.

The researchers fabricated such a thin-film structure (emitter) by co-sputtering 50 nm thick chromium metal and 50 nm thick chromium oxide onto a copper substrate. After deposition, a 50 nm thick tin oxide layer was deposited onto the chromium oxide layer to act as an antireflection coating. Spectrophotometer measurements from 300 to 1500 nm and Fourier-transform IR spectrometer measurements from 1500 nm to 20 μm showed that the film reduced IR radiation at wavelengths shorter than 5.5 μm (see figure).

A thin-film reflectance coating is the basis of an emissivity-modulated layer (inset shows a cross-sectional transmission-electron-microscope image) that shifts radiation toward the visible as shown in the plot of reflectance versus wavelength. (Courtesy of Shizuoka University)

The shift to visible emission (shorter wavelengths) occurs at temperatures between 580 and 870 K. Further mathematical modeling of the thin-film structure as a function of temperature shows that an emitter constructed with a reflectance cutoff wavelength in the visible region would have no IR component in its radiation spectrum and the conversion efficiency would exceed 90% at 2800 K. Because this efficiency is high, the bulb could be operated at lower voltages (with lower filament heating temperature), extending the lifetime of the emitter and the overall source.

Professor Makoto Tomita in the Department of Physics at Shizuoka University says, "We can make efficient monochromatic light sources such as blue, green, and red lamps by designing the reflectivity of a selective emitter. Almost 200 years have passed since the creation of the first incandescent light; however, there is ample scope for new discoveries and new applications in incandescence."–Gail Overton

REFERENCES
1. T. Matsumoto and M. Tomito, Opt. Exp. 18, 102, A192–A200 (Jun. 21, 2010).
2. T. Matsumoto et al., The Science and Technol. of Light Sources 12th Intl. Symp., paper CP091, Eindhoven, the Netherlands (Jul. 13, 2010).

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« Reply #101 on: October 12, 2010, 11:18:53 AM »

Interesting experiments on good old incandescent filaments.

One of the cop car spotlight manufacturers some years ago developed and marketed a replacement light unit that had higher visible light for the same power draw.  It wasn't just a halogen variant on the traditional sealed-beam, either, but something they too, had done with the filament composition.

In your post, I love how they noted the advantages of incandescent that would remain with the improved visible light spectrum..

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Ed/KB1HYS
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« Reply #102 on: October 12, 2010, 01:57:16 PM »

but will they work for a dummy load?  Wink
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« Reply #103 on: October 12, 2010, 02:38:48 PM »

Or in an EZ Bake oven?

but will they work for a dummy load?  Wink
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« Reply #104 on: October 12, 2010, 04:06:10 PM »

Will it keep my dogs warm in the winter.
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« Reply #105 on: October 12, 2010, 04:09:09 PM »

B,
Why dont you just put your feet over one of them thar ceramic heaters?
klc
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« Reply #106 on: October 12, 2010, 07:51:22 PM »

Edison invented that new bulb and suppressed its use since he made more money from power generation Shocked Grin
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Ed/KB1HYS
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« Reply #107 on: October 12, 2010, 09:44:06 PM »

Ah the conspiracy theory... I like it.  Perhaps the government has an alien designed "Super Bulb" that generates more light than power used, but the technology was surpressed by the electric companies?

oh wait, that was cars and oil... Cheesy
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73 de Ed/KB1HYS
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 "I've spent three quarters of my life trying to figure out how to do a $50 job for $.50, the rest I spent trying to come up with the $0.50" - D. Gingery
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« Reply #108 on: October 12, 2010, 09:59:11 PM »

Ah the conspiracy theory... I like it.  Perhaps the government has an alien designed "Super Bulb" that generates more light than power used, but the technology was surpressed by the electric companies?

oh wait, that was cars and oil... Cheesy

I have a Hammy Hambone Mirage wattmeter that shows more rf output than the rig is running DC input.
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« Reply #109 on: October 13, 2010, 08:30:23 AM »

I have a Hammy Hambone Mirage wattmeter that shows more rf output than the rig is running DC input.

And you're not even running a Class-E transmitter  Grin  Grin

At least it is good for bolstering one's ego  Grin
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« Reply #110 on: October 13, 2010, 08:48:00 AM »

Edison invented that new bulb and suppressed its use since he made more money from power generation Shocked Grin

And his lesser known cousin Fumy Edison invented the 200 MPG carburetor but was quickly bought out by sinister forces within the petrochemical industry.  It was left up to great great grandson Lodestone Edison to bring out the miraculous gas line magnets to restore the family name and win accolades from environmentalists and sleazy direct marketers from across the globe .
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« Reply #111 on: October 14, 2010, 11:15:44 PM »

Ban in Europe starts now for 100W incandescents.  People are hoarding.

I was an early adopter of CFL's in some fixtures.  If someone told me I had to use them, I'd be inclined to take them out. Here's the article in IEEE Spectrum.

http://spectrum.ieee.org/consumer-electronics/standards/deutschland-devours-the-last-of-its-100watt-incandescent-bulbs

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« Reply #112 on: October 16, 2010, 12:50:22 PM »

Ah the conspiracy theory... I like it.  Perhaps the government has an alien designed "Super Bulb" that generates more light than power used, but the technology was surpressed by the electric companies?

oh wait, that was cars and oil... Cheesy

I have a Hammy Hambone Mirage wattmeter that shows more rf output than the rig is running DC input.

Aptly named "Mirage". Their 6M leenyar is good though.

As for the ban in EU, now we can make money black marketing our lamps and edison sockets to Europe. Throw in a diode..
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