US 8,434,914 B2Granted

Lens generating a batwing-shaped beam distribution, and method therefor

AssigneeOsram Sylvania Inc.

InventorsMing Li, Yi Yang

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Abstract

A lens to redirect light, having an angular distribution centered around a left-right symmetry plane (LRSP), from a light source. The lens includes an incident face, facing the light source, which includes an incident corner, which divides the incident face into incident inner and outer zones and is concave, forming an obtuse angle in air. The lens also includes an opposite exiting face, which similarly includes an exiting corner, which similarly divides the exiting face. Each ray striking the incident inner zone transmits through the lens, striking the exiting inner zone. Each ray striking the incident outer zone transmits through the lens, striking the exiting outer zone. Each ray striking the incident face, transmits through the lens, strikes the exiting face, and refracts out of the lens, has initial and final propagation angles with respect to the LRSP. The final propagation angle is greater than the initial propagation angle.

Claims20

Dependent claims

A lens to redirect light from at least one light source, the light having an angular distribution centered around a left-right symmetry plane, the lens comprising:

an incident face facing the at least one light source, the incident face including at least one incident corner at which the local surface slope changes abruptly, the at least one incident corner dividing the incident face into an incident inner zone and an incident outer zone, the at least one incident corner being concave and forming an obtuse angle in air;
and
an exiting face opposite the incident face and including at least one exiting corner at which the local surface slope changes abruptly, the at least one exiting corner dividing the exiting face into an exiting inner zone and an exiting outer zone, wherein the exiting outer zone is defined by a partial curved surface extending from the at least one exiting corner, the partial curved surface including a generally flat portion adjacent the at least one exiting corner and a convex portion extending from the generally flat portion, wherein the generally flat portion is located beneath an intersection point of the exiting inner zone and extends past the intersection point;
wherein for each ray of the light from the at least one light source that strikes the incident inner zone and transmits through the lens, the ray strikes the exiting inner zone;
wherein for each ray of the light from the at least one light source that strikes the incident outer zone and transmits through the lens, the ray strikes the exiting outer zone;
and
wherein for each ray of the light from the at least one light source that strikes the incident face, transmits through the lens, strikes the exiting face, and refracts out of the lens, the ray has initial and final propagation angles formed with respect to the left-right symmetry plane, and the final propagation angle is greater than the initial propagation angle.

4 more elements

A method of redirecting light from at least one light source, the light having an angular distribution centered around a left-right symmetry plane, the method comprising:

refracting a central portion of the angular distribution through a proximal surface of a lens;
transmitting the refracted central portion through the lens;
totally internally reflecting the refracted central portion from a distal surface of the lens;
refracting the totally internally reflected central portion through the distal surface of the lens to exit the lens;
refracting a peripheral portion of the angular distribution through the proximal surface of the lens;
transmitting the refracted peripheral portion through the lens;
and
refracting the transmitted peripheral portion through the distal surface of the lens to exit the lens;
wherein the distal surface of the lens includes at least one generally flat portion that does not receive any light from the angular distribution, wherein the at least one generally flat portion is beneath a high-incident-angle surface on the distal surface of the lens and extends beyond the high-incident-angle surface;
and
wherein the central portion and the peripheral portion of the angular distribution refract through the distal surface on opposite sides of the generally flat portion.

8 more elements

A lens to redirect light from at least one light source, the light having an angular distribution centered around a longitudinal axis, the lens comprising:

an incident face facing the at least one light source, wherein a planar half-cross-section of the incident face, taken perpendicular to the longitudinal axis and extending away from the longitudinal axis, comprises:
a central portion that straddles the longitudinal axis;
and
a peripheral portion extending away from the central portion, the peripheral portion forming a corner with the central portion at which the local surface slope changes abruptly, the peripheral portion forming an obtuse angle in air with the central portion;
and
an exiting face opposite the incident face and facing away from the at least one light source, wherein a planar half-cross-section of the exiting face, taken perpendicular to the longitudinal axis and extending away from the longitudinal axis, comprises:
a central surface forming a concave corner at the longitudinal axis;
a high-incident-angle surface extending from the central surface generally toward the at least one light source and forming a convex wedge with the central surface, the high-incident angle surface forming an angle greater than 270 degrees in air with the central surface;
and
a partially curved surface extending from the high-incident-angle surface, the partially curved surface forming a corner with the high-incident-angle surface at which the local surface slope changes abruptly, the partially curved surface including a generally flat portion adjacent the exiting outer zone and a convex portion extending from the generally flat portion, wherein the generally flat portion is located beneath an intersection point formed by the intersection of the high-incident-angle surface and the central surface and extends past the intersection point.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/023,571Filed 9 Feb 2011 · continuation in part
Priority: 11 Dec 2009
Published: US 2011/0141729 A116 Jun 2011
Granted: 7 May 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification21 codes

F21V 5/04
Refractors for light sources: of lens shape
F21K 9/27
Light sources comprising attachment means: retrofit light sources for lighting devices with two fittings for each light source, e.g. for…
F21K 9/69
Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction: details of refractors…
F21S 4/28
With light sources held by or within elongate supports: rigid, e.g. LED bars