Illumination device having a tapered light guide

• US 9,244,212 B2
• Filed: 05/07/2014
• Issued: 01/26/2016
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Holman, Robert Louis, Sampsell, Matthew Brian
• Primary Examiner(s): Green, Tracie Y
• Application Number:
  US14/272,174
• Publication Number:
  US 20150036386A1
• Time in Patent Office: 629 Days
• Field of Search: 362/609, 362/600, 362/607, 362/623, 362/626, 349/115, 313501-511
• US Class Current: 1/1
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0008 the light being emitted at the end of the fibre
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0058 varying in density, size, shape or depth along the light guide
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• 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
• CPC Class Codes: Y10T 156/1089 of discrete laminae to single face of additional lamina

Abstract

This disclosure provides systems, methods and apparatus for illumination devices. In one aspect, an illumination device having a longitudinal axis includes a light source and a light guide. The light guide has a peripheral edge, a transmissive illumination surface, a center portion, and an upper surface. The transmissive illumination surface is oriented perpendicular to the longitudinal axis and disposed between the center portion and the peripheral edge. The upper surface is oriented relative to the illumination surface to define an angle α therebetween. In some implementations, the angle α can be greater than 15 degrees, for example.

Claims

1. An illumination device, comprising:

a first tapered light guiding section including;

a first light input surface extending along a longitudinal plane,

a first light output surface extending along a transverse plane disposed at an angle with respect to the longitudinal plane, and

a first inclined surface opposite the first light output surface, the first inclined surface disposed at an angle α

₁ with respect to the first light output surface, the angle α

₁ being less than 15 degrees;

a second tapered light guiding section including;

a second light input surface extending along the longitudinal plane,

a second light output surface extending along the transverse plane, and

a second inclined surface opposite the second light output surface, the second inclined surface disposed at an angle α

₂ with respect to the second light output surface, the angle α

₂ being less than 15 degrees; and

a light source disposed between the first light input surface and the second light input surface, the light source, the first light input surface and the second light input surface being collectively aligned such that

a portion of the light emitted from the light source illuminates the first light input surface, the first light guiding section configured to propagate light received through the first light input surface to the first light output surface, and

a portion of light emitted from the light source illuminates the second input surface, the second light guiding section configured to propagate light received through the second light input surface to the second light output surface, wherein at least a portion of light received from the light source and propagating in the first light guiding section propagates in a first direction, and at least a portion of light received from the light source and propagating in the second light guiding section propagates in a second direction opposite the first direction.

2. The device of claim 1, wherein the light source includes one or more light emitting diodes (LEDs).

3. The device of claim 1, wherein the light source includes an array of LEDs.

4. The device of claim 1, further comprising a coupling optic having an input aperture and an output aperture.

5. The device of claim 4, wherein a dimension of the output aperture of the coupling optic is different from a dimension of the input aperture.

6. The device of claim 4, wherein a dimension of the input aperture of the coupling optic is equal to a dimension of an output aperture of the light source.

7. The device of claim 4, wherein the coupling optic includes a curved reflector.

8. The device of claim 4, wherein the coupling optic includes an etendue preserving reflector.

9. The device of claim 1, further comprising a reflective surface positioned adjacent to the first or second inclined surface.

10. The device of claim 1, further comprising an optical conditioner positioned adjacent to the first or second light output surface.

11. The device of claim 10, wherein the optical conditioner includes a lenticular film or an array of lenslets.

12. The device of claim 1, wherein a cross-sectional shape of the light guide in the transverse plane is one of circular, triangular, rectangular, pentagonal, hexagonal, octagonal, or otherwise polygonal.

13. The device of claim 1, further comprising a light turning layer positioned adjacent to the first or second light output surface.

14. The device of claim 13, wherein the light turning layer includes a plurality of facets configured to redirect light by total internal reflection or specular reflection.

15. The device of claim 14, wherein at least some of the plurality of facets include a reflective layer.

16. A method of manufacturing an illumination device, the method comprising:

providing a first tapered light guiding section including;

a first light input surface extending along a longitudinal plane,

a first light output surface extending along a transverse plane disposed at an angle with respect to the longitudinal plane, and

a first inclined surface opposite the first light output surface, the first inclined surface disposed at an angle α

₁ with respect to the first light output surface, the angle α

₁ being less than 15 degrees;

providing a second tapered light guiding section including;

a second light input surface extending along the longitudinal plane,

a second light output surface extending along the transverse plane, and

a second inclined surface opposite the second light output surface, the second inclined surface disposed at an angle α

₂ with respect to the second light output surface, the angle α

₂ being less than 15 degrees; and

disposing a light source disposed between the first light input surface and the second light input surface, the light source, the first light input surface and the second light input surface collectively aligned such that

light emitted from the light source illuminates the first light input surface, the first light guiding section configured to propagate light received through the first light input surface to the first light output surface, and

light emitted from the light source illuminates the second input surface, the second light guiding section configured to propagate light received through the second light input surface to the second light output surface, wherein at least a portion of light received from the light source and propagating in the first light guiding section propagates in a first direction, and at least a portion of light received from the light source and propagating in the second light guiding section propagates in a second direction opposite the first direction.

17. The method of claim 16, wherein the light source includes one or more light emitting diodes (LEDs).

18. The method of claim 16, wherein the light source includes an array of LEDs.

19. The method of claim 16, further comprising providing a coupling optic having an input aperture and an output aperture different from the input aperture, the input aperture of the optic corresponding to an output aperture of the light source.

20. The method of claim 19, wherein the coupling optic includes a curved reflector.

21. The method of claim 19, wherein the coupling optic is an etendue preserving reflector.

22. The method of claim 16, further comprising providing a reflective surface adjacent the first or second inclined surface.

23. The method of claim 16, further comprising providing an optical conditioner adjacent the first or second light output surface.