Illumination device in which source light injection is non-parallel to device's optical axis

• US 9,459,398 B2
• Filed: 07/18/2014
• Issued: 10/04/2016
• Est. Priority Date: 07/18/2013
• Status: Active Grant

• Current Assignee: Quarkstar LLC
• Original Assignee: Quarkstar LLC
• Inventors: Schinagl, Ferdinand
• Primary Examiner(s): Dzierzynski, Evan
• Assistant Examiner(s): Dunay, Christopher E
• Application Number:
  US14/417,787
• Publication Number:
  US 20150168626A1
• Time in Patent Office: 809 Days
• US Class Current: 1/1
• 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 a light source configured to emit, during operation, light with a prevalent direction of propagation different from a direction of an optical axis of the illumination device; and an optical coupler including a transparent material, the optical coupler having an input aperture, an exit aperture and a first side surface and a second side surface arranged between the input aperture and the exit aperture, the exit aperture being centered on the optical axis of the illumination device. The optical coupler receives the emitted light through the input aperture from the light source. Further, the first side surface and the second side surface redirect the received light via total internal reflection (TIR) to the exit aperture. Additionally, the redirected light is issued through the exit aperture.

Claims

1. An optical coupler comprising:

an input aperture disposed within a first plane;

an exit aperture disposed within a second plane, the second plane intersecting the first plane at an acute tilt angle that is less than a critical TIR angle; and

a first side surface and a second side surface extending between the input aperture and the exit aperture, the first and second side surfaces configured to direct incident light from the input aperture to the exit aperture via total internal reflection, wherein

the first side surface is a first logarithmic spiral which depends on the acute tilt angle and the critical TIR angle,

the second side surface comprises a curved portion and a flat portion, the flat portion being oriented orthogonal to the second plane,

the flat portion of the second side surface is adjacent the exit aperture,

the curved portion of the second side surface is a second logarithmic spiral which depends on the acute tilt angle, the critical TIR angle and a dimension of the input aperture, and

the second side surface is continuous at an intersection of the curved portion with the flat portion.

2. The optical coupler of claim 1, wherein each of the first side surface and the second side surface has translational symmetry along an axis parallel to the first plane and the second plane.

3. An optical coupler comprising:

an input aperture disposed within a first plane;

an exit aperture disposed within a second plane, the second plane intersecting the first plane at an acute tilt angle that is equal to or larger than a critical TIR angle; and

a first side surface and a second side surface extending between the input aperture and the exit aperture, the first and second side surfaces configured to direct incident light from the input aperture to the exit aperture via total internal reflection, wherein

the first side surface is a first logarithmic spiral which depends on the acute tilt angle and the critical TIR angle,

the second side surface is flat and oriented orthogonal to the second plane.

4. The optical coupler of claim 3, wherein each of the first side surface and the second side surface has translational symmetry along an axis parallel to the first plane and the second plane.

5. The optical coupler of claim 3, wherein the acute tilt angle is less than or equal to twice the critical TIR angle.