Multi-color illuminating back light structure

In an embodiment, the invention provides a multi-color illuminating back light structure comprising a light guide, a reflector, at least one LED and a wavelength converter material. Micro-structures are formed on a first surface of the light guide. The reflector is attached to the first surface of the light guide. A wavelength converter material is deposited on a second surface of the light guide. At least one LED is optically coupled to at least one side of the light guide. A portion of light reflected from the micro-structures and the reflector is converted into light having at least one wavelength different from the wavelength of the reflected light. The light leaving the wavelength converter material comprises light with at least first and second wavelengths.