Systematic design of the color point of a white LED

Lighting is a crucial technology that is used every day. The introduction of the white light emitting diode (LED) that consists of a blue LED combined with a phosphor layer, greatly reduces the energy consumption for lighting. Despite the fast-growing market white LED's are still designed using slow, numerical, trial-and-error algorithms. Here we introduce a radically new design principle that is based on an analytical model instead of a numerical approach. Our design model predicts the color point for any combination of design parameters. In addition the model provides the reflection and transmission coefficients - as well as the energy density distribution inside the LED - of the scattered and re-emitted light intensities. To validate our model we performed extensive experiments on an emblematic white LED and found excellent agreement. Our model provides for a fast and efficient design, resulting in reduction of both design and production costs.