Collimation and homogenization system for an LED luminaire

#This application is a filing under 35 U.S.C. § 371 of International Application No. PCT/US2014/058682 filed Oct. 1, 2014 entitled, “Collimation and Homogenization System for an LED Luminaire.”

#The present disclosure generally relates to a method for controlling the light output from an array of light emitting diodes (LEDs) when used in a light beam producing luminaire, specifically to a method relating to improving the homogenization and collimation of the LEDs and for controlling the beam angle of the array.

#Luminaires with automated and remotely controllable functionality are well known in the entertainment and architectural lighting markets. Such products are commonly used in theatres, television studios, concerts, theme parks, night clubs, and other venues. A typical product will typically provide control over the pan and tilt functions of the luminaire, allowing the operator to control the direction the luminaire is pointing and thus the position of the light beam on the stage or in the studio. This position control is often done via control of the luminaire's position in two orthogonal rotational axes usually referred to as pan and tilt. Many products provide control over other parameters such as the intensity, color, focus, beam size, beam shape, and beam pattern. Additionally, it is becoming common to utilize high power LEDs as the light source in such luminaires and, for color control, it is common to use an array of LEDs of different colors. For example a common configuration is to use a mix of Red, Green and Blue LEDs. This configuration allows the user to create the color they desire by mixing appropriate levels of the three colors. For example illuminating the Red and Green LEDs while leaving the Blue extinguished will result in an output that appears Yellow. Similarly Red and Blue will result in Magenta and Blue and Green will result in Cyan. By judicious control of the LED controls the user may achieve any color they desire within the color gamut set by the LED colors in the array. More than three colors may also be used and it is well known to add an Amber or White LED to the Red, Green and Blue to enhance the color mixing and improve the gamut of colors available. The products manufactured by Robe Show Lighting such as the Robin 600 LEDWash are typical of the art.

#For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features and wherein:

#FIG. 1 illustrates a prior art LED lighting system;

#FIG. 2 illustrates a typical multiparameter automated LED luminaire system;

#Preferred embodiments of the present disclosure are illustrated in the FIGUREs, like numerals being used to refer to like and corresponding parts of the various drawings.

#The present disclosure generally relates to a method for controlling the light output from an array of LEDs when used in a light beam producing luminaire, specifically to a method relating to improving the homogenization and collimation of the LEDs and for controlling the beam angle of the array.

#Referring now to FIGS. 5, 6, and 7, FIG. 5 illustrates an embodiment of an optical system 100 of the disclosure. LED 60, which may include a primary optic, is mounted on substrate 62. LED 60 may contain a single color die or may contain multiple dies, each of which may be of differing colors. The light output from the dies in LED 60 enters collimating and mixing optic 80 at light entry port 82. Collimating and mixing optic 80 may be a solid optic using total internal reflection (TIR) to direct the light or may be a hollow reflective surface. Collimating and mixing optic 80 may have four sides 86, each of which may be curved with corners 92. The end view of collimating and mixing optic 80 in FIG. 6, combined with the side illustration of the collimating and mixing optic 80 in FIG. 5, illustrates details of an embodiment of the shape. The combination square sided shape with curved sides provides excellent mixing of the light from the dies 64 in LED 60. A further feature of collimating and mixing optic 80 is that it directs the reflected light to an external focal point which is comparatively close to its output port 84 of the collimating and mixing optic 80.