Faceted LED street lamp lens
AssigneeLight Engine Limited
InventorsYuk Tsan Sy, Wa Hing Leung
Life of this patent
Estimating the term…
Abstract
A lens for an LED street lamp has an external curved surface that has a concave surface portion on one side thereof. A back surface of the lens has a micro-prism array and retainer feet. A recess in the back surface receives an LED light source. The outer surface of the lens has facets or windows that provide overlapping projections of light from adjacent facets. The lens is generally cushion shaped with an indentation at one side. The lens directs light in an asymmetrical distribution transverse to the lens and to direct light symmetrically over a wide area in a longitudinal direction of the lens.
Claims16
A lens for an LED street lamp for use with an LED light source having a primary lens, comprising:
- a lens body of a secondary optical lens, the lens body having:
- a curved outer surface from which light is emitted, the curved outer surface having a first perimeter portion and a second perimeter portion opposite the first perimeter portion;
- a back surface opposite the curved outer surface, the back surface defining a recess for receiving the LED light source, the recess being closer to the first perimeter portion than to the second perimeter portion;
- a reflective micro-prism array formed on the back surface;
- the curved outer surface defining a concave surface portion at the first perimeter portion;
- a plurality of facets on the curved outer surface;
- and
- a mounting structure for mounting the lens body,
- wherein the lens body has a longitudinal axis and a transverse axis, the lens body being shaped to provide optical characteristics to emit light from the LED light source over a wide distribution angle at a cross section along the longitudinal axis and to emit light from the LED light source over an oblique distribution angle at a cross section along the transverse axis.
A method for directing light from an LED light source onto a surface, the light source defining a parallel plane that is parallel to a light emitting surface of the LED light source, comprising:
- enclosing a light emitting portion of the LED light source with a first refracting surface of an optical body,
- disposing the first refracting surface at a substantially constant distance from the LED light source in a first perpendicular plane;
- disposing the first refracting surface at a varying distance from the LED light source in a second perpendicular plane, the first and second perpendicular planes being perpendicular to one another and perpendicular to the parallel plane of the LED light source;
- directing light from the LED light source into the first refracting surface of the optical body;
- emitting the light from the LED light source from a second refracting surface of the optical body, the emitted light defining a refracting axis offset by an angle from the first perpendicular plane, the refracting axis of the emitted light being disposed in the second perpendicular plane, the emitted light having a greatest intensity at the refracting axis;
- the emitted light including emitting the light from the LED light source in an emission pattern having a greater extent along an axis parallel to the first perpendicular plane and a lesser extent along an axis in the second perpendicular plane;
- reflecting a portion of the light from the LED light source at the second refracting surface to generate first reflected light;
- and
- reflecting the first reflected light at a reflecting surface to provide a second reflected light, the second reflected light being directed toward the second refracting surface.
Dependencies are inferred from the claim text.