Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A high-pressure discharge lamp comprising a translucent discharge vessel which encloses a discharge space and has two sealed ends. Two electrodes extend from the sealed ends into the discharge space, and a fill is arranged in the discharge space for generating a gas discharge. Electrical feeds lead out of the sealed ends for supplying energy to the electrodes, with an electrically conductive layer acting as an ignition aid being arranged on the surface of the discharge vessel. The electrically conductive layer comprises at least a first layer section and a second layer section, the first layer section being arranged on a first sealed end of the discharge vessel and extends onto the surface of that region of the discharge vessel which encloses the discharge space. The second layer section is arranged on the second sealed end of the discharge vessel and extends onto the surface of that region of the discharge vessel which encloses the discharge space.