Optimum design domain of LED-based solid state lighting considering cost, energy consumption and reliability

Design parameters of LED-based solid state lighting products are interdependent and the corresponding requirements are dictated by operating conditions. We propose a scheme to define optimum design domains of LED-based luminaires for a given light output requirement by taking cost, energy consumption and reliability into consideration. First three required data sets to define design domains are expressed as contour maps in terms of the forward current and the junction temperature (If and Tj): (1) face lumen and cost requirement as lumen/LED; (2) power consumption and energy requirement as luminaire efficacy (LE); and (3) reliability requirement as L70 lifetime. Then, the available domain of design solutions is defined as a common area that satisfies all the requirements of a luminaire. The proposed scheme is implemented for a wall wash light and the optimum design solutions are presented.