Abstract: For mixing different light colors from different LEDs or energized phosphors, an elongated mixing tunnel is used having a reflective inner surface. LEDs of different colors are optically coupled along the length of the mixing tunnel and at a first end of the tunnel. Light coupled along the length of the tunnel is reflected by an angled dichroic mirror that selectively reflects the incoming color light towards a single output port of the mixing tunnel. The dichroic mirror passes all other colors of light being transmitted towards the output port of the tunnel. Two, three, or more colors of LEDs can be used. Efficient and compact ways to energize phosphors are also described. Other optical techniques are also described.

Abstract: Various optical techniques are described for obtaining a specified light output from an LED source. One technique uses a parabolic reflector surrounding an LED or LED array to create a collimated beam, and the light exit opening of the parabolic reflector is defined by a reflective disc with an opening of the desired size. Any generated light that is outside of the opening is reflected back into the parabolic reflector and re-reflected until the light exits the opening. For mixing different light colors from different LEDs or energized phosphors, a mixing tunnel is used. The mixing tunnel includes angled dichroic mirrors or angled polarizer mirrors that selectively reflect and pass selected colors or polarizations of light to a single output port of the mixing tunnel. Efficient and compact ways to energize phosphors are also described. Other optical techniques are also described.