LED-based high efficiency illumination systems for use in projection systems

An etendue folding illumination system for illuminating a target etendue comprising:

• two folded collimator/concentrators, each having an input aperture at a first end of the folded collimator/concentrator, and an output aperture at a second end of the folded collimator/concentrator opposite the first end, the folded collimator/concentrators each being a compound reflector having a reflective inner surface;
• a light combining assembly configured to couple light flux output of the two folded collimator/concentrators into an output aperture of the etendue folding illumination system;
• the first folded collimator/concentrator having either air gap or index matched coupled onto its input aperture a light source having a plurality of green LED dies, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture, and
• the second folded collimator/concentrator having either air gap or index matched coupled onto its input aperture a light source that is comprised of plurality of red and blue LED dies, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture,
• substantially flat reflective aperture stops coupled to each of the output apertures of the folded collimator/concentrators, each reflective aperture stop having an output clear aperture whose collimation angle, area and aspect ratio match corresponding parameters of the target etendue;
• light emitted by the LED dies and reflected by the reflective aperture stops passing back into the compound reflectors for further reflection by the reflective inner surfaces of the folded collimator/concentrators, the flat reflective surfaces of the LED dies, or both the reflective inner surface of the folded collimator/concentrators and the flat reflective surfaces of the LED dies.

An etendue folding illumination system for illuminating a target etendue comprising:

• three folded collimator/concentrators, each having an input aperture at a first end of the folded collimator/concentrator, and an output aperture at a second end of the folded collimator/concentrator opposite the first end, the folded collimator/concentrators each being a compound reflector having a reflective inner surface;
• a light combining assembly configured to couple the light flux output of the three folded collimator/concentrators into an output aperture of the etendue folding illumination system;
• the first folded collimator/concentrator having either air gap or index matched coupled onto its input aperture a light source comprising at least one green LED die, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture;
• the second folded collimator/concentrator having either air gap or index matched coupled onto its input aperture a light source comprising at least one red LED die, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture;
• the third folded collimator/concentrator having either air gap or index matched coupled onto its input aperture a light source comprising at least one blue LED die, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture;
• substantially flat reflective aperture stops coupled to each of the output apertures of the three folded collimator/concentrators, each reflective aperture stop having an output clear aperture whose collimation angle, area and aspect ratio match corresponding parameters of the target etendue;
• light emitted by the LED dies and reflected by the reflective aperture stops passing back into the compound reflectors for further reflection by the reflective inner surfaces of the folded collimator/concentrators, the flat reflective surfaces of the LED dies, or both the reflective inner surface of the folded collimator/concentrators and the flat reflective surfaces of the LED dies.

An etendue folding illumination system for illuminating a target etendue comprising:

• four folded collimator/concentrators arranged in a tiled configuration, each folded collimator/concentrator having an input aperture at a first end of the folded collimator/concentrator, the folded collimator/concentrators having their heights extended and conjoined to form a combining stem having a single conjoined output aperture at a second end of the folded collimator/concentrators opposite the first ends, the folded collimator/concentrators each being a compound reflector having a reflective inner surface;
• each of the folded collimator/concentrators having either air gap or index matched coupled onto its input aperture a light source comprising a plurality of LED dies of the same or multiple colors, each LED die having a flat reflective surface with a surface reflectance of at least 0.7 facing its output aperture;
• a substantially flat reflective aperture stop coupled to the output aperture of the folded collimator/concentrators, the reflective aperture stop having an output clear aperture whose collimation angle, area and aspect ratio match corresponding parameters of the target etendue;
• light emitted by the LED dies and reflected by the reflective aperture stops passing back into the compound reflectors for further reflection by the reflective inner surfaces of the folded collimator/concentrators, the flat reflective surfaces of the LED dies, or both the reflective inner surface of the folded collimator/concentrators and the flat reflective surfaces of the LED dies.

An etendue folding illumination system for illuminating a target etendue comprising:

• a folded collimator/concentrator having an input aperture at a first end of the folded collimator/concentrator, and an output aperture at a second end of the folded collimator/concentrator opposite the first end, the folded collimator/concentrator being a compound reflector having a reflective inner surface;
• a light source coupled to the input aperture of the folded collimator/concentrator, the light source having a plurality of light emitting diode (LED) dies of one or multiple colors providing light flux into the folded collimator/concentrator, the LED dies having a flat reflective surface with a surface reflectance of at least 0.7 facing the output aperture;
• a substantially flat reflective aperture stop coupled to the output aperture of the folded collimator/concentrator, the reflective aperture stop having an output clear aperture whose collimation angle, area and aspect ratio match corresponding parameters of the target etendue;
• light emitted by the LED dies and reflected by the reflective aperture stop passing back into the compound reflector for further reflection by the reflective inner surface of the folded collimator/concentrator, the flat reflective surfaces of the LED dies, or both the reflective inner surface of the folded collimator/concentrator and the flat reflective surfaces of the LED dies.