Light guide within recessed housing

• US 6,848,822 B2
• Filed: 05/31/2002
• Issued: 02/01/2005
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Randall, Stephen M., Lundin, David J., Ballen, Todd A., Lea, Michael C.
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US10/160,400
• Publication Number:
  US 20030223250A1
• Time in Patent Office: 977 Days
• Field of Search: 362135-137, 362154-156, 362/26, 362/30, 362/560, 362/571, 362/577, 405/47
• US Class Current: 362/577
• CPC Class Codes: F21S 43/235 Light guides
• CPC Class Codes: F21V 33/00 Structural combinations of lighting devices with other articles, not otherwise provided for
• CPC Class Codes: F21V 33/0048 Office articles, e.g. bookmarks, desk lamps with drawers, stands for books or music scores
• CPC Class Codes: F21W 2121/02 for fountains
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre

Abstract

The invention is directed to an illumination apparatus that includes a light guide within a recessed housing. A light source, such as a light emitting diode can be used to provide light to the light guide. The light is transmitted through the light guide via total internal reflection (TIR), and can be emitted in a controlled manner to ensure that a desired angular distribution of light is achieved without substantially illuminating interior side walls of the recessed housing. In this manner, efficient lighting can be provided. In one embodiment, the invention is can be implemented within a cosmetic compact that includes a mirror. The compact may incorporate aspects of the invention by implementing a light guide within a ring-shaped recess of the compact to provide facial lighting to a user.

Claims

1. An illumination apparatus comprising:

a housing formed with a recess, wherein the recess defines a ring-like shape and includes one or more interior side walls;

a mirror surface on the housing, wherein the mirror surface is substantially surrounded by the ring-like shaped recess;

a light guide that transmits light via total internal reflection (TIR) positioned within the recess such that the light guide is in proximity to the one or more interior side walls; and

a set of notches formed on the light guide along a centerline axis of the tight guide to define an angular distribution of light emitted from the light guide, wherein the angular distribution of the light defined by the set of notches and emitted from the light guide is such that the light is angularly dispersed from the recess without substantially illuminating the interior side walls.

2. The illumination apparatus of claim 1, wherein the set of notches comprise a first set of notches formed on the light guide along a first centerline axis of the light guide, the apparatus further comprising a second set of notches formed on the light guide along a second centerline axis of the light guide wherein the angular distribution of the light is defined by the first and second sets of notches.

3. The illumination apparatus of claim 2, wherein the first and second sets of notches are arranged such that two notches in the first set separate each notch in the second set.

4. The illumination apparatus of claim 1, further comprising one or more light sources positioned to input light into the tight guide for light transmission via total internal reflection (TIR).

5. The illumination apparatus of claim 4, wherein the one or more light sources include one or more light emitting diodes.

6. The illumination apparatus of claim 1, wherein the illumination apparatus forms a light fixture.

7. The illumination apparatus of claim 1, wherein the apparatus comprises a compact.

8. The illumination apparatus of claim 1, wherein the angular distribution of light emitted from the light guide is directed out of the recess toward an illumination plane parallel to the ring-like shaped recess at a defined distance from the housing.

9. The illumination apparatus of claim 8, wherein the defined distance is between approximately 5 and 50 centimeters.

10. The illumination apparatus of claim 1, wherein angularly distributed light emitted from the light guide substantially overlaps at a defined distance from the housing.

11. The illumination apparatus of claim 10, wherein the defined distance is between approximately 2 and 50 centimeters.

12. The illumination apparatus of claim 1, wherein a diameter of a ring formed by the ring-shaped recess is approximately between 2 and 50 centimeters.

13. The illumination apparatus of claim 12, wherein the diameter of the ring formed by the ring-shaped recess is approximately between 5 and 10 centimeters.

14. The illumination apparatus of claim 1, wherein the set of notches comprise a first set of notches formed on the light guide along a first centerline axis of the light guide, the apparatus further comprising a second set of notches formed on the light guide along a second centerline axis of the light guide.

15. The illumination apparatus of claim 14, wherein the first set of notches are located approximately 5 degrees from points of the light guide in closest proximity to a bottom of the recess in a direction toward a center of the housing.

16. The illumination apparatus of claim 15, wherein the second set of notches are located approximately 30 degrees from points of the light guide in closest proximity to a bottom of the recess in a direction away from a center of the housing.

17. The illumination apparatus of claim 16, wherein notch angles associated with the notches in the first and second sets are approximately 80 degrees.

18. The illumination apparatus of claim 17, wherein the notches in the first and second sets are each separated by approximately 1.5 millimeters.

19. The illumination apparatus of claim 18, wherein notch depths associated with the notches in the first and second sets are approximately 0.3 millimeter.

20. An illumination apparatus comprising:

a housing formed with a recess, wherein the recess defines a ring-like shape and includes one or more interior side walls;

a light guide positioned within the recess such that the light guide is ni proximity to the one or more interior side walls; and

one or more light extraction features in the light guide that define an angular distribution of light emitted from the light guide, wherein the angular distribution of the light emitted from the light guide is such that the light is angularly dispersed from the recess without substantially illuminating the interior side walls, wherein the light extraction features include a first set of notches formed on the light guide along a first centerline axis of the light guide and a second set of notches formed on the light guide along a second centerline axis of the light guide, wherein the first set of notches are located approximately 5 degrees from points of the light guide in closest proximity to a bottom of the recess in a direction toward a center of the housing, wherein the second set of notches are located approximately 30 degrees from points of the light guide in closest proximity to a bottom of the recess in a direction away from a center of the housing, wherein notch angles associated with the notches in the first and second sets are approximately 80 degrees, wherein the notches in the first and second sets are each separated by approximately 1.5 millimeters, wherein notch depths associated with the notches in the first and second sets are approximately 0.3 millimeter, and wherein the notches are arranged such that two notches in the first set separate each notch in the second set.

21. The illumination apparatus of claim 20, wherein the light guide has a diameter of approximately 5 millimeters.

22. A method comprising:

positioning a light guide that transmits light via total internal reflection (TIR) substantially within a recessed housing, wherein the recessed housing defines a ring-like shape and defines one or more interior side walls, and wherein the recessed housing includes a mirror surface on the housing, wherein the mirror surface is substantially surrounded by the ring-like shaped recess; and

emitting light from the light guide via a set of notches formed on the light guide along a centerline axis of the light guide so as to substantially maximize angular distribution of light without substantially illuminating the walls of the recessed housing, wherein an angular distribution of the light defined by the set of notches and emitted from the light guide is such that the light is angularly dispersed from the recess without substantially illuminating the walls of the recessed housing.

23. The method of claim 22, further comprising:

emitting light from the light guide so as to substantially maximize both the angular distribution of light and light intensity without substantially illuminating the walls of the recessed housing.

24. An illumination apparatus comprising:

a housing formed with a recess, wherein the recess defines a ring-like shape and includes one or more interior side walls; and

a mirror surface on the housing, wherein the mirror surface is substantially surrounded by the ring-like shaped recess;

a light guide that transmits light via total internal reflection (TIR) positioned substantially within the recess such that the light guide is in proximity to the one or more interior side walls, wherein the light guide is formed with one or more means for emitting light, wherein the means for emitting light define an angular distribution of light from the light guide, and wherein the angular distribution of light omitted from the light guide is such that light is angularly dispersed from the recess without substantially illuminating the one or more interior side walls, wherein the means for emitting light comprise notches fanned on the light guide along a centerline axis of the light guide.

25. The illumination apparatus of claim 24, wherein the means for emitting light comprise a first set of notches formed on the light guide along a first centerline axis of the light guide and a second set of notches formed on the light guide along a second centerline axis of the light guide wherein angular distribution of the light is defined by the first and second sets of notches.

26. An illumination apparatus comprising:

a housing formed with a recess, wherein the recess includes one or more interior side walls;

a mirrored surface formed on the housing, wherein the recess surrounds the mirrored surface;

a light guide positioned within the recess such that the light guide is in proximity to the one or more interior side walls, wherein the light guide is formed with light extraction features that define an angular distribution of light emitted from the light guide, wherein the light extraction features comprise a set of notches and are arranged such that the angular distribution of the light defined by the light extraction features and emitted from the light guide is such that the light is angularly dispersed from the recess without substantially illuminating the interior side wails, and wherein the light extraction features are arranged such that the angular distribution of the light defined by the light extraction features and emitted from the light guide defines an illumination plane at a defined distance from the housing.

27. The illumination apparatus of claim 26, wherein the defined distance is between approximately 5 and 50 centimeters.

28. The illumination apparatus of claim 26, the defined distance is such that when a user handles the illumination apparatus and views the mirrored surface a face of the user is illuminated at the illumination plane.

29. The illumination apparatus of claim 26, wherein the apparatus comprises a compact.

30. The illumination apparatus of claim 26, wherein greater than approximately 50 percent of light transmitted through the light guide illuminates a target at the illumination plane.

31. The illumination apparatus of claim 26, wherein light guide transmits light via total internal reflection (TIR).