Backlight with structured surfaces

• US 20060051048A1
• Filed: 09/14/2005
• Published: 03/09/2006
• Est. Priority Date: 10/08/1999
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Cobb, Sanford Jr., Kretman, Wade D., Epstein, Kenneth A., Gardiner, Mark E.
• Granted Patent: US 7,873,256 B2
• Time in Patent Office: Days
• US Class Current: 385/146
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• 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 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A backlight includes a lightguide, a light source disposed with respect to the lightguide to introduce light into the lightguide and a turning film. Optical structures are formed in one of an output surface and a back surface of the lightguide. The optical structures are arranged to extract light from the lightguide. A back reflector is disposed adjacent the back surface. The optical structures are formed to include a varying pattern arranged to mask non-uniformities in the output of the lightguide.

Claims

1. A lightguide comprising:

an optically transmissive substrate having a first surface, an opposite second surface, and an edge surface; and

an optically transmissive film bonded to the first surface of the substrate and having a plurality of optical structures formed therein,

the light guide being adapted to receive light from a light source through the edge surface of the substrate, the plurality of optical structures extracting the received light out of the lightguide.

2. The lightguide of claim 1, wherein the substrate is a wedge.

3. The lightguide of claim 1, wherein the substrate is a slab.

4. The lightguide of claim 1, wherein the optical structures are spaced within about 50 to 100 microns of each other.

5. The lightguide of claim 1, wherein the optical structures are arranged in a pattern to correct non-uniformities in light exiting the first surface of the substrate.