Illumination device having a light guide with leaky side surfaces

• US 10,473,847 B2
• Filed: 07/18/2014
• Issued: 11/12/2019
• Est. Priority Date: 07/18/2013
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: York, Allan Brent
• Primary Examiner(s): May, Robert J
• Assistant Examiner(s): Macchiarolo, Leah Simone
• Application Number:
  US14/905,744
• Publication Number:
  US 20160161656A1
• Time in Patent Office: 1,943 Days
• Field of Search: 40546, 40553, 40570
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21V 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2101/00 Point-like light sources
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0006 Coupling light into the fibre in general G02B6/4298
• CPC Class Codes: G02B 6/0008 the light being emitted at the end of the fibre
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64

Abstract

An illumination device includes one or more light-emitting elements (LEEs) arranged to provide light; a light guide includes a receiving end and an opposing end, the receiving end being arranged to receive the light provided by the LEEs. The light guide further includes a pair of opposing side surfaces extending along a length of the light guide between the receiving and opposing ends. The light guide is configured to guide the received light in a forward direction, along the length of the light guide toward the opposing end, and transmit a first portion of the guided light into ambient through one or more of the opposing side surfaces as sideways leaked light. The illumination device further includes an extractor located at the opposing end and configured to output into the ambient a remaining portion of the guided light—that reaches the opposing end—as output light in backward directions.

Claims

1. An illumination device comprising:

one or more light-emitting elements (LEEs) arranged to provide light;

a light guide comprising

a receiving end and an opposing end, the receiving end arranged to receive the light provided by the LEEs, and

a pair of opposing side surfaces extending along a length of the light guide between the receiving end and the opposing end, the light guide configured to

guide the received light in a forward direction, along the length of the light guide toward the opposing end of the light guide, and

transmit a first portion of the guided light into ambient environment through one or more of the opposing side surfaces as sideways leaked light; and

an optical extractor located at the opposing end and configured to output into the ambient environment a remaining portion of the guided light—

that reaches the opposing end—

as output light in backward directions,

wherein the light guide is tapered such that

a receiving aperture at the receiving end of the light guide is larger than an output aperture at the opposing end,

an angle of incidence of guided light incident on the opposing side surfaces exceeds a critical angle beyond a predetermined distance from the receiving end, and

some of the light guided beyond the predetermined distance transmits into the ambient environment through the opposing side surfaces as the sideways leaked light.

2. The illumination device of claim 1, wherein at least one of the opposing side surfaces is planar.

3. The illumination device of claim 2, wherein both of the opposing side surfaces are planar.

4. The illumination device of claim 1, wherein

the light provided by the LEEs is in a first angular range, and

a numerical aperture of the light guide is such that the light received from the LEEs in the first angular range can be guided by the light guide through TIR off the pair of opposing side surfaces.

5. The illumination device of claim 1 further comprising one or more optical couplers, wherein

the light provided by the LEEs is in a first angular range,

the optical couplers are arranged to receive the light provided by the LEEs and redirect it to the receiving end of the light guide in a second angular range, and

a numerical aperture of the light guide is such that the light received from the optical couplers in the second angular range can be guided by the light guide through TIR off the pair of opposing side surfaces.

6. The illumination device of claim 1, wherein the LEEs are LEDs that emit white light.

7. The illumination device of claim 1, wherein the optical extractor comprises at least one redirecting surface, the at least one redirecting surface of the optical extractor being adapted to reflect at least a portion of the guided light in a direction that has a component orthogonal to the forward direction.

8. The illumination device of claim 1, wherein the optical extractor comprises

a first redirecting surface adapted to reflect at least a portion of the guided light in a first direction that has a component orthogonal to the forward direction, and

a second redirecting surface adapted to reflect at least a portion of the guided light in a second direction that has a component orthogonal to the forward direction and antiparallel to the first direction.