DESCRIPTION (provided by applicant): Conventional microscope bulbs burn out, degrade, and produce a great deal of unnecessary light and heat. For fluorescence microscopy and imaging, only monochromatic, narrow band spectra are generally required, yet with conventional microscopy light sources a significant amount of light and heat is discarded. Solid state, Light Emitting Diode (LED) illumination can provide an illumination source that is well controlled, will not degrade over time, and offers some unique advantages for multi-spectral narrow band illumination. In Phase I of this research grant, we will demonstrate that 1) white multi-die LED illumination modules can be used for general purpose microscope illumination, 2) single and dual wavelength multi-die LED illumination modules can be used for quantitative imaging, and 3) that multi-die LED illumination modules can be used for fluorescence microscopy. The modules being prototyped consists of multiple tiny LED dies (not the large discrete LEDs known in everyday uses) on a single substrate in a group about the size of a standard tungsten halogen bulb filament. In Phase II commercial prototypes will be developed, along with control hardware and software to adjust intensity, choose colors, and allow strobing of the LEDs. With the large number of microscopes in use for medicine and biology, materials science, and in the semiconductor industry, the potential market for these innovative light sources is immense.