Abstract: The invention describes a method of cooling a lamp (1) in a projector (2, 2?) independently of an orientation (Pdesk, Pceiling) of the projector (2, 2?), which method comprises directing a cooling airflow (4) symmetrically at a burner (10) of the lamp (1) during operation of the lamp (1); and controlling the cooling airflow (4) alternately between at least a first cooling level (C-I) and a second cooling level (C-II) such that, during cooling at the first cooling level (C-I), the temperature (Tbase) in a base region of the burner (10) drops below a predefined minimum operating temperature (Tmin) to allow a blackening of an inside wall (100) of the burner (10), and during cooling at the second cooling level (C-II), the temperature (Ttop) in an upper region of the burner (10) increases above a predefined maximum operating temperature (Tmax) and the temperature (Tbase) in the base region of the burner (10) increases above the predefined minimum operating temperature (Tmin) to facilitate a cleaning of the burner

Abstract: The invention describes a method of cooling a lamp (1) in a projector (2, 2?) independently of an orientation (Pdesk, Pceiling) of the projector (2, 2?), which method comprises directing a cooling airflow (4) symmetrically at a burner (10) of the lamp (1) during operation of the lamp (1); and controlling the cooling airflow (4) alternately between at least a first cooling level (C-I) and a second cooling level (C-II) such that, during cooling at the first cooling level (C-I), the temperature (Tbase) in a base region of the burner (10) drops below a predefined minimum operating temperature (Tmin) to allow a blackening of an inside wall (100) of the burner (10), and during cooling at the second cooling level (C-II), the temperature (Ttop) in an upper region of the burner (10) increases above a predefined maximum operating temperature (Tmax) and the temperature (Tbase) in the base region of the burner (10) increases above the predefined minimum operating temperature (Tmin) to facilitate a cleaning of the burner

Abstract: The invention describes a method of shutting down a high pressure discharge lamp (1) in which a pair of electrodes (2) is disposed in an arc tube (3), which method comprises reducing, upon receipt of a shut-down request (SR), the lamp power (P) towards a reduced power level (PR) required to sustain a long-term arc discharge between the electrodes (2), and driving the lamp (1) towards the reduced power level (PR) for a reduced power duration before completely shutting down the lamp power (P), whereby, prior to reducing the lamp power (P) towards the reduced power level (PR), the lamp power (P) is reduced to an undershoot power level (Pu), which undershoot power level (Pu) is lower than the reduced power level (PR) required to sustain a long-term arc discharge between the electrodes (2), and the lamp is driven at this undershoot power level (Pu) for an undershoot power duration (tu) before increasing the lamp power (P) again to approach the reduced power level (PR).

Abstract: The invention describes a method of shutting down a high pressure discharge lamp (1) in which a pair of electrodes (2) is disposed in an arc tube (3), which method comprises reducing, upon receipt of a shut-down request (SR), the lamp power (P) towards a reduced power level (PR) required to sustain a long-term arc discharge between the electrodes (2), and driving the lamp (1) towards the reduced power level (PR) for a reduced power duration before completely shutting down the lamp power (P), whereby, prior to reducing the lamp power (P) towards the reduced power level (PR), the lamp power (P) is reduced to an undershoot power level (Pu), which undershoot power level (Pu) is lower than the reduced power level (PR) required to sustain a long-term arc discharge between the electrodes (2), and the lamp is driven at this undershoot power level (Pu) for an undershoot power duration (tu) before increasing the lamp power (P) again to approach the reduced power level (PR).