A light source apparatus including light spectrum-converting materials that emit light primarily over large portions of the 360 nm-480 nm and the 590-860 nm spectral range is provided. This apparatus provides a cooled, high-luminance, high-efficiency light source that can provide a broader spectrum of light within these spectral ranges than has been cost-practical by using many different dominant peak emission LEDs. Up to 15% of the output radiant power may be in the spectral range 350-480 nm in one embodiment of this device, unless a specific separate source and lamp operating mode is provided for the violet and UV. Control methods for light exposure dose based on monitoring and controlling reflected or backscattered light from the illuminated surface and new heat management methods are also provided. This flexible or rigid light source may be designed into a wide range of sizes or shapes that can be adjusted to fit over or around portions of the bodies of humans or animals being treated, or mounted in such a way as to provide the special spectrum light to other materials or biological processes. This new light source can be designed to provide a cost-effective therapeutic light source for photodynamic therapy, intense pulsed light, for low light level therapy, diagnostics, medical and other biological applications as well as certain non-organic applications.
