Method for Stabilizing the Temperature Dependency of Light Emission of an LED

• US 20080111079A1
• Filed: 10/10/2007
• Published: 05/15/2008
• Est. Priority Date: 05/14/2004
• Status: Active Grant

• Current Assignee: Teledyne FLIR Defense Incorporated (Teledyne Technologies Incorporated)
• Original Assignee: ICx Radiation GmbH
• Inventors: Saucke, Karen, Pausch, Guntram, Stein, Juergen
• Granted Patent: US 7,642,516 B2
• Time in Patent Office: Days
• US Class Current: 250/363.01
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0295 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 1/08 Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
• CPC Class Codes: G01J 1/30 using electric radiation detectors
• CPC Class Codes: G01T 1/40 Stabilisation of spectrometers
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

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.

Claims

1-19. -19. (canceled)

20. 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.

21. 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 20;

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.

22. The light detector of claim 21, 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,

23. The light detector of claim 21, whereby the signal processor is adapted to digitally generate the stabilizing factor and stabilize the output signals of the light detector.

24. A scintillation detector for measuring radiation, comprising the light detector of claim 21, wherein the light detector is adapted to measure, at least partially, light generated by the scintillation detector.

25. The scintillation detector of claim 24, wherein the radiation is ionized radiation.

26. The scintillation detector of claim 24, 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.

27. The scintillation detector of claim 26, wherein the signal processor is adapted to determine the temperature-contingent second stabilizing factor using a calibration table.

28. The scintillation detector of claim 26, 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.

29. The scintillation detector of claim 26, wherein the scintillator includes a scintillation crystal.