Internal collecting reflector optics for LEDs
An optical system is disclosed that uses an LED light source. The light output is coupled to an optic element formed from a material with a high refractive index. The coupling of the light to the high index material significantly reduces the cone angle of the light. The system is very efficient in that nearly all the light generated by the LED is directed to the intended subject.
1. An optical system with a directed output, the optical system comprising:
an entirely solid light-transmissive optic element comprising a light output surface and, opposite the light output surface, a reflective surface shaped to create an internal reflection effect, the solid optic element further comprising a side wall spacing apart the light output surface and the reflective surface;
a light pipe extending from the solid optic element adjacent an edge of the light output surface, the light pipe having a proximal end optically coupled to the solid optic element and a distal end remote from the solid optic element; and
an LED light source at and mounted in optical contact with the distal end of the light pipe, the light source and the light pipe directing the light output surface to direct light into the solid optic element towards the reflective surface, wherein the light from the light source is reflected by the reflective surface to form an output light beam that exits the solid optic element through the light output surface,
wherein a length of the light pipe is shorter than a distance between the light output surface and the reflective surface.
2. The optical system of claim 1 , wherein the solid optic element is configured such that an angle between the centerline of the light output by the light source and a centerline of light reflected from the reflective surface is no more than 60 degrees.
3. The optical system of claim 1 , wherein the reflective surface is sized, angled relative to the light output surface, and offset from the light output surface such that positive and negative rays of a cone of light output from the light pipe are incident thereon adjacent an edge thereof.
4. The optical system of claim 1 , wherein the light pipe has a center line angled at more than 0 degrees and at no more than 60 degrees relative to a normal to the light output surface.
5. The optical system of claim 1 , wherein the light pipe comprises an optical fiber.
6. The optical system of claim 1 , wherein the reflective surface is parabolic.
7. The optical system of claim 6 , wherein the output light beam is collimated.
8. The optical system of claim 6 , wherein the proximal end of the light pipe is located at a focal point of the parabolic reflector surface.
9. The optical system of claim 1 , wherein the reflective surface is elliptical.
10. The optical system of claim 1 , wherein the reflective surface is aspheric.
11. The optical system of claim 1 , wherein an index of refraction of the optic element is no less than 1.3.
12. The optical system of claim 1 , wherein the light source comprises more than one LED die.
13. A lighting system with a directed output, the lighting system comprising an array of optical systems in accordance with claim 1 .
14. The optical system of claim 1 , wherein the solid optic element is cylindrical.
15. The optical system of claim 1 , wherein the solid optic element comprises one of acrylic or polycarbonate.
16. The optical system of claim 1 , wherein:
the solid optic element comprises a facet adjacent an edge of, and non-parallel to, the light output surface; and
the proximal end of the light pipe is mounted in optical contact with the facet.
17. The optical system of claim 1 , wherein the light from the light source that is directed into the solid optic element reflects off the reflective surface at acute angles to reduce a cone angle of the light output from the light source.
18. The optical system of claim 1 , wherein an intersection of a centerline of the light pipe and the reflective surface is closer to a midpoint of the reflective surface than an edge of the reflective surface.
19. The optical system of claim 1 , wherein a line normal to a tangent to a midpoint of the reflective surface is angled relative to normal to the light output surface and directed toward the proximal end of the light pipe.
20. The optical system of claim 1 , wherein a line normal to a tangent to a midpoint of the reflective surface intersects the light output surface between a midpoint of the light output surface and the proximal end of the light pipe.