Electron-stimulated luminescence

For the phenomenon in materials science, see Cathodoluminescence.
An ESL lamp.

Electron-stimulated luminescence (ESL) was a claimed method of producing light by cathodoluminescence,[1][2][3][4] i.e. by a beam of electrons made to hit a fluorescent phosphor surface. This is also the method used to produce light in a cathode ray tube (CRT), but, unlike CRTs, ESL lamps do not include magnetic or electrostatic means to deflect the electron beam.[5]

A cathodoluminescent light has a transparent glass envelope coated on the inside with a light-emitting phosphor layer. Electrons emitted from a cathode strike the phosphor; the current returns through a transparent conductive coating on the envelope. The phosphor layer emits light through the transparent face of the envelope. The system has a power supply providing at least 5kVDC to the light emitting device, and the electrons transiting from cathode to anode are essentially unfocused. Additional circuits allow triac-type dimmers to control the light level.[6] Lights produced so far have a color rendering index of 90. The energy consumption can be 70% less than that of a standard incandescent light bulb. Claimed lifetime can be as long as 10,000 hours which is more than ten times that of a standard incandescent light bulb.[7]

Unlike fluorescent lamps, which produce light through the electrical excitation of mercury vapor, ESL lamps do not use mercury.[8] The first commercially available ESL product was a reflector bulb.

Drawbacks include high weight, a slightly larger-than-normal base and – as with compact fluorescent lamps – when switched on, a slight delay before illumination begins and a static charge which attracts dust to the bulb face. As of 2015 the claimed efficiency is roughly half that of commercially available LED bulbs, although it is considerably better than that of traditional incandescent lamps.[9]

See also

References

  1. ↑ "Vu1 Corporation sees bright future for ESL light bulbs -- Engadget". 100902 engadget.com
  2. ↑ "Company Claims ESLs to be the Future of Light Bulbs (w/ Video)". 100902 physorg.com
  3. ↑ "Are ESL bulbs better than CFL or LED? – Crave - CNET". 100902 news.cnet.com
  4. ↑ greenprophet.com - Are ESLs A Mercury-Free Replacement for CFL Lights? | Green Prophet (2012-03-12).
  5. ↑ "The Promise of a Better Light Bulb?". The New York Times. 9 April 2009.
  6. ↑ http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7834553.PN.&OS=PN/7834553&RS=PN/7834553
  7. ↑ "Newest Lightbulb Tech Combines Advantages of Incandescent, Fluorescent, and LED". 100902 popsci.com
  8. ↑ ""Will ESL Light Bulbs Beat LEDs?"". Forbes.
  9. ↑ http://www.diylife.com/2011/01/26/esl-light-bulbs-diy-product-review/

External links

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