Lighting devices with patterned printing of diffractive extraction features

Patent metadata

Field	Value
Publication number	US-9470838-B2
Application number	US-201414486823-A
Country	US
Kind code	B2
Filing date	Sep 15, 2014
Priority date	Aug 13, 2012
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

Extended area lighting devices include a light guide and diffractive surface features on a major surface of the light guide, at least some diffractive surface features adapted to couple guided-mode light out of the light guide. The diffractive features include first and second diffractive features disposed on respective first and second portions of the major surface. A patterned light transmissive layer, including a second light transmissive medium, optically contacts the second diffractive features but not the first diffractive features. A first light transmissive medium optically contacts the first but not the second diffractive features. The first and second portions may define indicia, and the first and second diffractive features provide low distortion for viewing objects through the light guide such that the indicia is not readily apparent to users when guided-mode light does not propagate within the light guide. Optical films having such diffractive features are also disclosed.

First claim

The invention claimed is:

1. A lighting device, comprising:
a light guide having a first major surface, the first major surface having first and second diffractive surface features formed in first and second portions thereof respectively, at least one of the first and second diffractive surface features adapted to couple guided-mode light out of the light guide; and
a patterned light transmissive layer in optical contact with the second diffractive surface features but not the first diffractive surface features, the patterned layer comprising a second light transmissive medium;
a first light transmissive medium in optical contact with the first diffractive surface features but not the second diffractive surface features;
wherein the first and second light transmissive media have different first and second refractive indices respectively at a visible wavelength; and
wherein the light guide is non-flat.

2. The device of claim 1 , wherein the light guide is simply curved.

3. The device of claim 1 , wherein the light guide is complex curved.

4. The device of claim 1 , wherein the first and second refractive indices differ by at least 0.05.

5. The device of claim 1 , wherein the first and second portions of the first major surface define indicia.

6. The device of claim 1 , further comprising:
one or more light sources disposed proximate the light guide to provide the guided-mode light in the light guide.

7. The device of claim 1 , wherein the first light transmissive medium is air.

8. The device of claim 1 , wherein the second light transmissive medium is an adhesive.

9. The device of claim 1 , wherein the first and second light transmissive media are both polymer compositions.

10. The device of claim 1 , wherein the first and second light transmissive media are both substantially transparent and colorless.

11. The device of claim 1 , wherein the first major surface comprises a first group of diffractive surface features having a first uniform pitch and a second group of diffractive surface features having a second uniform pitch.

12. The device of claim 1 , wherein the first major surface comprises groups of diffractive surface features having differing pitches to form pitch-related indicia.

13. The device of claim 12 , wherein the first and second portions of the first major surface define second indicia.

14. The device of claim 13 , wherein the pitch-related indicia is in registration with the second indicia.

15. The device of claim 13 , wherein the pitch-related indicia is not in registration with the second indicia.

16. A lighting device, comprising:
a light guide having a first major surface, the first major surface having first and second diffractive surface features formed in first and second portions thereof respectively, at least one of the first and second diffractive surface features adapted to couple guided-mode light out of the light guide; and
a patterned light transmissive layer in optical contact with the second diffractive surface features but not the first diffractive surface features, the patterned layer comprising a second light transmissive medium;
a first light transmissive medium in optical contact with the first diffractive surface features but not the second diffractive surface features;
wherein the first and second light transmissive media have different first and second refractive indices respectively at a visible wavelength; and
wherein the first major surface comprises groups of diffractive surface features having differing pitches to form pitch-related indicia.

17. The device of claim 16 , wherein the first and second portions of the first major surface define second indicia.

18. The device of claim 17 , wherein the pitch-related indicia is in registration with the second indicia.

19. The device of claim 17 , wherein the pitch-related indicia is not in registration with the second indicia.

Assignees

• 3M Innovative Properties Co

Inventors

• Thompson David S
• Yang Zhaohui
• Stay Matthew S
• Jones Vivian W

Classifications

• G02B6/005

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B6/0038 Primary

  Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide · CPC title

• G02B6/0035

  provided on the surface of the light guide or in the bulk of it · CPC title

• G02B6/006

  to produce indicia, symbols, texts or the like · CPC title

• G02B6/0036

  2-D arrangement of prisms, protrusions, indentations or roughened surfaces · CPC title