Method of calibrating light delivery systems, light delivery systems and radiometer for use therewith

Abstract

In a method of calibrating a light delivery device () having a solid state light source (), for example comprising LEDs of an LED array, and an intensity control unit () comprising LED array driver and a dimmer module for generating a control signal for controlling at least the intensity of the light source, the light source is temporarily connected by a light guide () to a radiometer () for detecting irradiance of the delivered light. The light delivery device has a memory () for storing control signal parameters and associated radiance levels. The light delivery device is calibrated by adjusting the control signal parameters, e.g. a PWM duty cycle of a control signal to each of a series of predetermined settings, obtaining from the radiometer a corresponding series of delivered light irradiance levels measured thereby, storing the irradiance levels and associated control signal parameters in memory, and applying a best fit algorithm to the irradiance measurements and control signal parameters. Thereafter, a desired irradiate level can be set by selecting the best fit control signal parameters, such as duty cycle of a PWM control or other parameters. Output intensity levels may be measured at the same time as the irradiance levels and used to compensate for light source output level changes when setting a desired irradiance level.