Lightguide design techniques

• US 9,063,262 B2
• Filed: 08/29/2012
• Issued: 06/23/2015
• Est. Priority Date: 08/29/2012
• Status: Active Grant

• Current Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Original Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Inventors: Huang, Qiong, Li, Ming, Yang, Yi, Olsen, Joseph A.
• Primary Examiner(s): Ullah, Akm Enayet
• Application Number:
  US13/597,445
• Publication Number:
  US 20140064660A1
• Time in Patent Office: 1,028 Days
• Field of Search: 385 31- 37
• US Class Current: 1/1
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

Techniques are disclosed for obtaining a desired luminance and/or intensity distribution from any lighting fixture that is illuminated by a lightguide. The techniques can be used, for instance, to design a non-uniform surface texture (e.g., of light extraction features) for a lightguide, wherein the surface texture achieves a desired uniform or an intentionally non-uniform luminance distribution for a given lightguide shape/geometry, dimensions, and/or composition. In some embodiments, an iteration algorithm with illuminance distribution feedback is utilized to design a non-uniform surface texture (e.g., geometry, dimensions, quantity and/or spatial distribution of light extraction features) to achieve the target luminance distribution for a given lighting application.

Claims

1. A method of designing a lightguide device comprising:

dividing a lightguide surface having an initial distribution of light extraction features into a plurality of zones including a first and a second zone; and

adjusting the light extraction features of the first zone differently than the light extraction features of the second zone, such that light will be extracted from the first zone differently than from the second zone due to the difference in their corresponding light extraction features.

2. The method of claim 1, wherein adjusting the light extraction features of the first zone differently than the light extraction features of the second zone comprises:

calculating a light distribution parameter for the first zone;

comparing the resultant calculated light distribution parameter for the first zone to a target light distribution parameter for the first zone; and

adjusting the light extraction features of the first zone until the light distribution parameter for the first zone is within a given tolerance of the target light distribution parameter for the first zone.

3. The method of claim 2, wherein the light distribution parameter comprises spatial and/or angular distribution of at least one of luminance, illuminance, luminous intensity, color, color temperature, and/or color rendering index (CRI).

4. The method of claim 2, wherein the light distribution parameter for the first zone is different than a light distribution parameter for the second zone.

5. The method of claim 2, wherein adjusting the light extraction features of the first zone differently than the light extraction features of the second zone further comprises:

increasing light extraction feature density for the first zone if the calculated light distribution parameter is lower than the target light distribution parameter for the first zone;

or

decreasing light extraction feature density for the first zone if the calculated light distribution parameter is higher than the target light distribution parameter for the first zone.

6. The method of claim 2 further comprising repeating the calculating, comparing, and adjusting for the second zone.

7. The method of claim 1, wherein a density of the light extraction features of the first zone is different than a density of the light extraction features of the second zone.

8. The method of claim 1, wherein a composition of the light extraction features of the first zone is different than a composition of the light extraction features of the second zone.

9. The method of claim 1, wherein the light extraction features of the first zone are of a different size than the light extraction features of the second zone.

10. The method of claim 1, wherein the light extraction features of the first zone are of a different shape than the light extraction features of the second zone.

11. The method of claim 1, wherein the plurality of zones further comprises one or more additional zones of light extraction features each of which is configured uniquely with respect to the other zones.

12. The method of claim 1, wherein the plurality of zones provides a continuously varying light extraction pattern.