The present disclosure relates generally to light-emitting devices and in particular to a color-tunable light source module with brightness control.
Light sources based on light-emitting diodes (LEDs) are emerging as an energy-efficient replacement for conventional incandescent or halogen light sources in a variety of applications. Compared to conventional light sources, LED-based light sources can provide significantly higher energy efficiency and longer life.
However, a number of challenges must be addressed to provide practical LED-based light sources. For example, a given LED emits light in a narrow band of wavelengths, which creates challenges for the production of white light (which is generally a mixture of different wavelengths). Further, not all white light is created equal. The human eye is sensitive to the differences among white-light sources such as fluorescent light, incandescent light, and sunlight. These differences can be quantified in terms of well-known metrics such as color temperature (CCT) and/or color rendering index (CRI).
In addition, to provide sufficient light for many applications, high brightness and therefore high operating current is required. High current can lead to a buildup of heat, which can damage the LEDs. Accordingly, effective heat transfer and/or other techniques are significant in the design of high-performance LED-based light sources.