Method For Coupling Light Into A Thin Planar Waveguide

• US 20100220956A1
• Filed: 11/02/2006
• Published: 09/02/2010
• Est. Priority Date: 11/02/2006
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Levola, Tapani Kalervo, Saarikko, Pasi Risto Olavi, Laitinen, Pauli
• Granted Patent: US 8,155,489 B2
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials

Abstract

A light distributing device (100) comprises a thin planar waveguide (10) and a waveguiding ridge (20). An incoming light beam (B1) coupled into the ridge (20) forms a second light beam (B2) waveguided in the ridge (20). The ridge (20) and the planar waveguide (10) have a common portion (23) such that light is further coupled from the side of the ridge (20) into the planar waveguide (10) through said common portion (23). Thus, optical power of a broad incoming beam (B1) may be effectively coupled to a relatively thin planar waveguide (10). The planar waveguide (10) may further comprise diffractive out-coupling elements (30) to direct light towards a display (400).

Claims

1. A device comprising:

a ridge, and

a substantially planar waveguide comprising at least one out-coupling portion,

wherein said ridge has an end for coupling light into said ridge in order to form a light beam waveguided longitudinally within said ridge, said ridge and said planar waveguide having a common portion to couple light out of said ridge sideways into said planar waveguide, and said out-coupling portion being adapted to couple light out of the plane of said planar waveguide.

2. The device according to claim 1, wherein said out-coupling portion comprises a diffraction grating.

3. The device according to claim 1, wherein said ridge comprises one or more light redistributing features to increase an angle between light rays of said beam and the centerline of said ridge.

4. The device according to claim 1, wherein said ridge has two or more branches.

13. The device according to claim 1 further comprising a light source, wherein the end of said ridge is arranged to couple light emitted from said light source into said ridge so as to form the light beam waveguided longitudinally within said ridge.

14. The device according to claim 13 further comprising a keyset, wherein said at least out-coupling element is adapted to direct light out of the plane of said planar waveguide in order to form at least one light beam associated with features of said keyset.

15. The device according to claim 13 further comprising a display, wherein said at least out-coupling element is adapted to direct light out of the plane of said planar waveguide in order to form at least one light beam adapted to provide light to said display.

5-12. -12. (canceled)

16. A method of distributing light by using a ridge and a substantially planar waveguide, said method comprising:

coupling light into said ridge to form a light beam waveguided longitudinally in said ridge, and

coupling light out of said ridge sideways into said planar waveguide through a common portion of said ridge and said planar waveguide.

17. The method according to claim 16 further comprising coupling light out of the plane of said planar waveguide.

18. The method according to claim 17 further comprising lighting a display.

19. The method according to claim 17 wherein the light coupled out of the plane of said planar waveguide is associated with features of a keyset.

20. A device comprising a light distributing means, said light distributing means in turn comprising:

a first waveguiding means, and

a second waveguiding means, said second waveguiding means in turn comprising a light out-coupling means,

wherein the second waveguiding means is thicker than said first waveguiding means, said second waveguiding means having a light receiving means to couple light into said second waveguiding means to form a light beam waveguided longitudinally in said second waveguiding means, said first waveguiding means and said second waveguiding means having a common portion to couple light out of said second waveguiding means sideways into said first waveguiding means, and said out-coupling means being adapted to couple light out of the plane of said first waveguiding means.

21. The device according to claim 20 further comprising a light source, wherein said light receiving means is arranged to couple light emitted from said light source into said second waveguiding means.