Method for stabilizing the temperature dependency of light emission of an LED
View Patent ↗Method for correction of the temperature dependency of a light quantity L emitted by a light emitting diode (LED), being operated in pulsed mode with substantially constant pulse duration t P , and measured in a light detector, using a predetermined parameter X, correlated to the temperature T of the LED in a predetermined ratio, whereby a correction factor K is determined from the parameter X, preferably using a calibration table, especially preferred using an analytic predetermined function, whereby the measured emitted light quantity L is corrected for the temperature contingent fluctuations of the emitted light quantity, whereby the parameter X is determined from at least two output signals of the LED, which are related to each other in a predetermined manner.
1. A compensation device, comprising:
means for operating an LED in pulsed mode;
means for measuring the emitted light quantity as an output signal of the LED using a light detector, to provide a measured light output value;
means for determining a parameter that is related to the temperature of the LED in a predetermined relation, based on at least two output signals of the LED that are related to each other in a predetermined manner with respect to temperature;
means for determining a correction factor from the parameter; and
means for correcting the measured light output value for temperature-dependent fluctuations of the emitted light quantity according to the correction factor.
2. A light detector, comprising:
a signal processor; and
an optical connection adapted to connect the LED to the light detector;
wherein the signal processor includes the compensation device of claim 1 ;
wherein the signal processor is further adapted to generate a stabilizing factor according to signals emitted by the LED; and
wherein the signal processor is further adapted to stabilize output signals of the light detector according to the stabilizing factor.
3. The light detector of claim 2 , wherein the light detector is selected from the group consisting of a photo multiplier, a hybrid photo multiplier, an Avalanche photo diode, and a photo diode with amplifier.
4. The light detector of claim 2 , whereby the signal processor is adapted to digitally generate the stabilizing factor and stabilize the output signals of the light detector.
5. A scintillation detector for measuring radiation, comprising the light detector of claim 2 , wherein the light detector is adapted to measure, at least partially, light generated by the scintillation detector.
6. The scintillation detector of claim 5 , wherein the radiation is ionized radiation.
7. The scintillation detector of claim 5 , further comprising a scintillator that absorbs the radiation and generates an output signal according at least in part to the absorbed radiation and depending on the operating temperature of the detector, and a connector that is adapted to connect the LED to the scintillation detector in a heat-conducting manner, wherein
the stabilizing factor is a first stabilizing factor,
an optical path of the optical connection between the LED and the light detector includes the scintillator,
the signal processor is adapted to determine a temperature-contingent second stabilizing factor according to first stabilizing factor and related to a temperature of the scintillator in a predetermined ratio, and
the scintillation detector is adapted to measure and stabilize the output signal according to the second stabilizing factor.
8. The scintillation detector of claim 7 , wherein the signal processor is adapted to determine the temperature-contingent second stabilizing factor using a calibration table.
9. The scintillation detector of claim 7 , wherein the signal processor is adapted to determine the temperature-contingent second stabilizing factor using a predetermined functional dependency from the parameter of the LED.
10. The scintillation detector of claim 7 , wherein the scintillator includes a scintillation crystal.