Patent ID: 7377688

Claim:
A method for determining the bulb temperature (T) of high pressure discharge lamps that comprises the following steps: a) ascertaining a first spectral radiant power (M P ) at a first wavelength (λ P ); b) ascertaining a second spectral radiant power (M C ) at a second wavelength (λ C ) different from the first; c) determining a quotient (β) from the first and second radiant power; and d) determining the temperature (T) of the bulb on the basis of this quotient in that the temperature (T) of the bulb is determined from the following equation: β ⁢ ⁢ ( T ) = β 0 ⁡ [ 1 + exp ⁢ ⁢ ( T C - R · P - T T 0 ) ] β 0 , T C , R and T 0 designating lamp-specific constants, P the electric power, T the lamp temperature and β the quotient (M P /M C ) of the first and second radiant power.