Patent ID: 8231230

Claim:
Method for generating light of a given wavelength for an image projection device, in which LED semiconductor light sources (HL n ) that emit light in n different primary colors (GF k ) (k=1. . . n; n>2) are activated sequentially each for a given time period (t), wherein the LED semiconductor light sources (HL n ) are supplied with a constant electrical voltage (U) and an electric current (I), characterized in that the current flowing through the LED semiconductor light sources (HL n ) is controlled by at least one switch ( 17 ), the at least one switch ( 17 ) receiving a switching voltage which controls activation of the at least one switch ( 17 ), the switching voltage being synchronized with a clock signal generated by a system clock, wherein the current flowing through the LED semiconductor light sources (HL n ) is further converted into a voltage equivalent to the current and is supplied to an integrator which generates an integrated voltage value, and wherein the integrated voltage value is compared with a reference voltage, and when the reference voltage is reached by the integrated voltage value, the switching voltage of the at least one switch ( 17 ) is interrupted after synchronization with the system clock, resulting in an interruption of the current supplied to the LED semiconductor light sources (HL n ) so that the current is equivalent to the optical energy to be emitted from the LED semiconductor light sources (HL n ) during the time period (t), with the flowing current not being kept constant and a pulse-width modulation being carried out, wherein the driving of the individual LED semiconductor light sources is performed as a function of the integration of the optical energy output by the light sources.