'Planon' Dielectric Barrier Excimer Lamp

Osram's 'Planon' was the first general lighting lamp based on dielectric barrier discharge technology to be marketed. It's flat panel nature and very thin construction, just 8.5mm thick, makes its performance unlike any other light source.

The arrangement consists of two parallel glass sheets with a gap between them. The inner surface of each is coated with a phosphor and the space between them is sealed and filled with xenon gas at fairly high pressure. Small glass X-studs at regular intervals strengthen the panel.

The anode and cathode electrodes are printed onto the lower glass sheet in a regular array (see second close-up photo below), with several tens of electrode pairs spread throughout the panel. The anodes are the point-like tips and the cathodes are the continuous lines, with the result that the discharge occurring between each electrode pair is triangular in shape (see last close-up image). A pattern of dots printed on the upper panel diffuses the light above each discharge. What makes the lamp special is that the electrodes are not in contact with the discharge, from which they are separated by a dielectric barrier. This preserves the electrodes and slows the rate of wear on them, increasing lamp life. The wavelength of energy produced is 172nm, and this stimulates the phosphor coatings. Owing to the absence of mercury the degeneration of the phosphor is slowed, the lamp reaches full output almost immediately, luminance remains constant from -30°C to +85°C, and disposal is easy.

Planon lamps have found applications in LCD backlights, X-Ray viewers, in architectureal lighting installations, and most famously on the KPN Telecom tower in Amsterdam.
Manufacturer: Osram GmbH
Lamp Power: 68 Watts System: 90 Watts
Lamp Current: Amps System: 0.90-0.38 Amps
Lamp Voltage: Volts System: 100-240 Volts
Operating Frequency 80Hz - 40 Hz, variable, to allow for dimming
Cap: Flying leads (six)
Bulb Type: FP-8.5R/460 18.1" diagonal length
Panel Width: 384 mm outer dimension 364 mm luminous area
Panel Height: 317 mm outer dimension 292 mm luminous area
Electrodes: Dielectric barrier type printed on glass panel
Atmosphere: Xe2* Xenon excimer
Luminous Flux & Efficacy: 1,850 lm (at 100 hrs) 27 lm/W (at 100 hrs)
Panel Centre Luminance: 5,900 cd/m2
Colour Temperature & CRI: CCT: 7400K CRI: Ra 86
Chromaticity Co-ordinates: CCx: 0.304 CCy: 0.295
Burning Position: Universal
Rated Life: 100,000hrs (50% lumens) 50,000hrs (20% failures)
Warm Up / Re-strike Time: Instantaneous Instantaneous
Factory: Herbrechtingen, Germany
Date of Manufacture: 2002
Original / Present Value: Approx. £200 (2003)
References: 1) www.planon.de.