Light emitting device

摘要

A light emitting device comprises: a surface light source for a surface-emission; a CPC lens having a light receiving surface, a side reflective surface, and a light emitting surface, the light receiving surface receiving a part of light from the surface light source, the side reflective surface reflecting the light from the light receiving surface, and the light emitting surface facing the light receiving surface and emitting the light; and a reflector containing the surface light source and the CPC lens, and having a concaved reflective surface for reflecting forward the light deviating the light receiving surface from the surface light source, wherein a ratio of a illumination area of the surface light source to an area of the light receiving surface of the CPC lens is not less than 0.63 and not more than 2.93.

主权项

1. A light emitting device comprising:
a surface light source having a first light emitting surface, the surface light source comprising a plurality of light emitting diode elements adapted to emit light; a CPC lens having a light receiving surface, a side reflective surface, and a second light emitting surface, the light receiving surface spaced a distance from the surface light source, the light receiving surface receiving a first part of the light from the plurality of light emitting diode elements, the side reflective surface reflecting a portion of the first part of the light received by the light receiving surface, and the second light emitting surface facing the light receiving surface and forwardly emitting the first part of the light; and a reflector containing the surface light source and the CPC lens, and having a concave reflective surface for reflecting forward a second part of the light which is not received by the light receiving surface from the plurality of light emitting diode elements, wherein a ratio of an illumination area (mm2) of the surface light source to an area (mm2) of the light receiving surface of the CPC lens is not less than 0.63 and not more than 2.93, the distance between the first light emitting surface of the surface light source and the light receiving surface of the CPC lens is between 0.5 mm and 4.0 mm, the light emitting device further comprising:
an annular opening between the light emitting surface of the CPC lens and the concave reflector surface, andan annular clear cover covering the annular opening; wherein the CPC lens has a center axis; and the side reflective surface of the CPC lens is a surface of revolution determined by revolving first and second parabolas with a central focus on the center axis of the CPC lens, wherein: a first focal point of the first parabola is located on the second parabola; a second focal point of the second parabola is located on the first parabola; a first axis of the first parabola passes through the first focal point; a second axis of the second parabola passes through the second focal point; and an angle formed by the first axis and the second axis defines an aperture angle of the CPC lens.