Tir lens for light emitting diodes

• US 8,449,150 B2
• Filed: 02/03/2009
• Issued: 05/28/2013
• Est. Priority Date: 02/03/2009
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Inventors: Allen, Steven C., Luo, Hong, Hohl-AbiChedid, Angela
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US12/364,934
• Publication Number:
  US 20100195335A1
• Time in Patent Office: 1,575 Days
• Field of Search: 362/520, 362/545, 362/244, 362/245, 362/249.02, 362/308, 362/311.02, 362/311.06, 362/311.15, 362/311.11, 362/327, 362/335, 362/339, 362/340, 313/512
• US Class Current: 362/311.06
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21V 5/048 the lens being a simple lens adapted to cooperate with a point-like source for emitting mainly in one direction and having an axis coincident with the main light transmission direction, e.g. convergent or divergent lenses, plano-concave or plano-convex lenses
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An optical element is disclosed. The optical element includes a single, transparent, rotationally-symmetric lens with a batwing shaped cross-section, extending angularly away from a longitudinal axis. The lens also includes a variety of curved, straight, specular and optionally diffuse portions on its longitudinal and transverse faces, all of which cause a variety of internal and external reflections, refractions, and optionally scattering.

Claims

1. A device comprising:

a light-emitting diode module with a Lambertian light output;

a lens made of a transparent material and having symmetry about a longitudinal axis, the lens comprising;

an interior surface proximate the light-emitting diode module and having a concave portion centered on the longitudinal axis, such that any light entering the lens from the light emitted from the light-emitting diode module enters through the concave portion, the interior surface further having a total internal reflection portion circumferentially surrounding the concave portion, such that any light ray that enters the lens through the concave portion and directly strikes the total internal reflection portion does so at an incident angle greater than a critical angle for the lens; and

an exterior surface facing away from the light-emitting diode module and through which light exits the lens, the exterior surface having a lateral edge and a distal curvilinear portion further including a distal convex portion and a distal concave portion, the distal convex portion defining a maximum distal longitudinal extent of the lens;

wherein the interior and exterior surfaces define a batwing-shaped structure;

the lens converting light rays emitted from the light-emitting diode module into a generally uniform output distribution of light rays emerging from the lens;

wherein the lens includes an inner longitudinal thickness proximate the longitudinal axis, an outer longitudinal thickness proximate the lateral edge of the exterior surface, and an intermediate longitudinal thickness between the longitudinal axis and the lateral edge and thus between the inner Longitudinal thickness and the outer Longitudinal thickness, the intermediate longitudinal thickness being greater than both the inner longitudinal thickness and the outer longitudinal thickness.

2. The device of claim 1, wherein the lens has a rotational symmetry about the longitudinal axis.

3. The device (10) of claim 1, wherein the generally uniform output distribution (5) of light rays emerging from the lens (10A) comprises:

a first plurality of light rays that enter the lens (10A) through the concave portion (29) and then directly exit the lens (10A) through the batwing structure; and

a second plurality of light rays that enter the lens (10A) through the concave portion (29), internally reflect at least once from the batwing structure, then exit the lens (10A) through the batwing structure.

4. The device of claim 1, wherein the concave portion of the interior surface is hemispherical in shape and wherein any light ray that enters the lens from the light-emitting diode module (3) does so at normal incidence through the concave portion of the interior surface.

5. The device of claim 1, wherein the exterior surface includes at least one bump on a distal portion opposite the interior surface, the at least one bump being proximate the longitudinal axis.

6. The device of claim 1, wherein the lateral edge is parallel to the longitudinal axis and is directly adjacent to the total internal reflection portion.

7. The device of claim 1, wherein a ratio of a lateral diameter of the lens, divided by a diameter of the concave portion is in the range of 6:

1 and 4;

1.