Koninklijke Philips Corporation N.v.

Martin Stroesser

Michael Haacke

Jens Pollmann-Retsch

Pavel Pekarski

The invention describes a method of heating a preform () characterized by a radius (R), a material thickness (t), and a material absorption spectrum, which method comprises the steps of selecting, depending on a desired temperature profile, a desired effective absorption coefficient for the preform () on the basis of the preform radius (R) and material thickness (t); generating a laser radiation beam (L) comprising radiation with a wavelength spectrum compiled on the basis of absorption coefficients of the absorption spectrum to satisfy the effective absorption coefficient and directing the laser radiation beam (L) at the preform () to heat the preform (). The invention further describes a driving arrangement () for controlling a laser radiation generating unit () of a preform heating system (), a preform heating system (), and a computer program.

Method of heating a preform, a driving arrangement, a preform heating system and a computer program

In order to achieve a discharge lamp suited to operate under reduced nominal power of e.g. 20-30 W, a lamp is proposed with two electrodes () arranged at a distance in a discharge vessel () for generating an arc discharge. The discharge vessel () has a filling with a substantially free of mercury and comprises a metal halide and a rare gas. The lamp () further comprises an outer bulb () arranged around the discharge vessel at a distance (d). The outer bulb () is sealed and has a gas filling of a thermal conductivity (&#x3bb;). The inner diameter (d) of the discharge vessel is preferably in a range from 2-2.7 mm. The wall thickness (w) is in a range from 1.4-2 mm. A heat transition coefficient (&#x3bb;/d) is calculated as thermal conductivity (&#x3bb;) at 800&#xb0; C. of the outer bulb filling divided by the distance (d). The so-defined heattransition coefficient is below 150 W/(mK).

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Aachen, Germany

Martin Stroesser