Tunable LED lamp - Design and thermal management

The aim of the present work is the design and construction of LED lamp with tunable spectral characteristics. In order to achieve basic light property as spectral power distribution (SPD) of daylight at noon and late afternoon, particular mixture of LEDs with different spectral and power characteristics and proper control of the LEDs´ operation are used. The differences in the LEDs´ thermal properties and operational regimes complicate the lamp´s thermal management and demand precise investigation of the LEDs´ thermal performance. These analyses are made at different ambient temperatures ranging from 20°C to 45°C and various current values through LEDs - up to their maximum values. Infrared thermography is used for the evaluation of the temperature distribution on LEDs and the heat sink. Thermal management investigations are used in order to define safety operating conditions for LEDs in different ambient conditions.