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

A control device of a projection device for projecting at least one image onto a projection surface, the projection device comprising:

• at least one discharge lamp operated by alternating current with a first electrode and a second electrode,
• a control device for driving the discharge lamp, wherein the control device is designed to drive the discharge lamp in such a way that the at least one image is projected with a specifiable refresh rate onto the projection surface, wherein the control device is designed to provide at least one base current waveform for driving the discharge lamp, wherein the base current waveform exhibits a current commutation scheme that is described by a commutation vector that comprises a binary value for specifiable locations of a possible current commutation which states whether a current commutation takes place at the location concerned, and
• a measuring device for determining a measured value correlated to a state variable of the discharge lamp,
• wherein the control device is designed, on the basis of an evaluation of at least one measured value of the measuring device determined during a drive of the discharge lamp with a current waveform to be checked, to check the current waveform in respect of its suitability for minimizing an electrode burn-back of the first electrode and the second electrode,
• 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.

A method for projecting at least one image onto a projection surface by means of a projection device, which comprises at least one discharge lamp with a first electrode and a second electrode, and a control device for driving the discharge lamp, wherein the control device is designed to drive the discharge lamp in such a way that the at least one image is projected with a specifiable refresh rate onto the projection surface, wherein the control device is designed to provide at least one base current waveform for driving the discharge lamp, wherein the base current waveform exhibits a current commutation scheme that is described by a commutation vector that comprises a binary value for each location of a specifiable current commutation which states whether a current commutation takes place at the location concerned, as well as a measuring device for determining a measured value correlated to a state variable of the discharge lamp,

• the method comprising:
• determining at least one measured value of the measuring device during a drive of the discharge lamp with a current waveform to be checked,
• checking the current waveform with respect to its suitability for minimizing an electrode burn-back of the first electrode and the second electrode, on the basis of an evaluation of the at least one measured value, and in the case of a positive check result, retaining the checked current waveform, and
• in the case of a negative check result, depending on a checked commutation vector characterizing the checked current waveform, generating a modified commutation vector that characterizes a modified current waveform by means of a specifiable algorithm.