Osram Gmbh

Marc Czichy

Norbert Magg

Dirk Grundmann

Michael Boenigk

Michael Heise

Daniel Sixtensson

Markus Baier

Melanie Zumkley

Detlef Guenther

Bastian Dobler

A projection apparatus includes a discharge lamp; a control apparatus for controlling a discharge current through the lamp. The apparatus is designed in a first drive mode, to control the discharge current having an amplitude profile; in a second drive mode, to control the discharge current in accordance with the amplitude profile; and to change between the first mode and the second mode. The time difference between two changes is given by a first time interval, and the time difference between the change from the first mode to the second mode and a next instance of leaving the second mode is given by a second time interval. The apparatus further includes a control device to determine a first manipulated variable depending on a control deviation determined by the difference between a target voltage value and a measured voltage value, and to determine the first and/or the second time interval therefrom.

Projection apparatus for projecting at least one frame onto a projection surface and method therefor

A projection device for projecting at least one image onto a projection surface is provided. According to the present disclosure, a control device of the projection device is designed, on the basis of an evaluation of at least one measured value of a measuring device of the projection device determined during a drive of a discharge lamp of the projection device with a current waveform to be checked, to check the current waveform in respect of its suitability for minimizing an electrode burn-back of a first electrode and a second electrode, and in the case of a positive check result, to retain the checked current waveform, and in the case of a negative check result, depending on a checked commutation vector characterizing the checked current waveform, to create, by means of a specifiable algorithm, a modified commutation vector that characterizes a modified current waveform.

Projection device and method for projecting at least one image onto a projection surface

Various embodiments provide a projection arrangement. The projection arrangement may include a discharge lamp; and a ballast for the discharge lamp. The ballast is designed to provide, during operation of the projection arrangement, a lamp current in the form of alternating current and having an average frequency and a preset waveform, which has a preset commutation scheme, to the discharge lamp. The preset commutation scheme is preset by a preset time sequence of commutations of the lamp current. The ballast is designed to provide the lamp current in such a way that the preset commutation scheme of the lamp current is deviated from repeatedly with at least one preset intervening time period by at least one DC phase with a preset time duration.

Method for operating a discharge lamp and projection arrangement

Various embodiments provide a method for determining a wave form of a lamp current for operating a discharge lamp of a projection arrangement having a color wheel and a ballast, such that a polarity of the electrodes is commutated in accordance with a commutation scheme of the wave form. The method involves providing a wave form having a commutation scheme and checking whether operation of the discharge lamp satisfies one criterion relating to a lifetime of the discharge lamp or a flicker amplitude of the projection arrangement. If the criterion checked is satisfied, checking whether operation of the discharge lamp satisfies the other of the two criteria is carried out. If at least these two criteria are satisfied, the wave form is stored in a memory of the projection arrangement and provided as the predefinable wave form at the ballast for the discharge lamp.

Method for determining a predefinable wave form of a lamp current for operating a discharge lamp of a projection arrangement, and projection arrangement

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Berlin, Germany

Marc Czichy