OPTICAL WAVEGUIDE WITH LIGHT EMITTING DEVICE AND OPTICAL TOUCH PANEL

• US 20100188367A1
• Filed: 12/14/2009
• Published: 07/29/2010
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Nagafuji, Akiko, Shimizu, Yusuke
• Granted Patent: US 8,358,887 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02B 2006/12154 Power divider
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/138 by using polymerisation
• CPC Class Codes: G02B 6/2804 forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

In an optical waveguide 10 with a light emitting device to be used in the present invention, branched points 16 are sequentially provided in a guiding light direction 17 of a main path 14 and the width of the main path 14 becomes narrower as the main path 14 moves away from a light emitting device 11. The optical waveguide 10 having this structure can reduce a width W1 because there are no portions that correspond spaces (cladding layers) among adjacent branched paths 15. Moreover, the optical waveguide 10 has an excellent optical transmission efficiency, resulting in high intensity of light emitted. Uniformity of the light emitted is equal or more than a conventional optical waveguide 60 with a light emitting device.

Claims

1. An optical waveguide with a light emitting device comprising:

a light emitting device; and

an optical waveguide including a core for guiding light emitted from the light emitting device to generate light beams,

wherein the core comprises;

a main path; and

a plurality of branched paths branched at branched points from the main path,

the branched points are sequentially provided in a guiding light direction, and

the width of the main path becomes narrower as the main path moves away from the light emitting device.

2. The optical waveguide according to claim 1, wherein the core is embedded in a cladding layer and the core has a refractive index higher than the cladding layer.

3. The optical waveguide according to claim 2, wherein the maximum refractive index difference between the core and the cladding layer is 0.02 to 0.2.

4. The optical waveguide according to claim 2 or claim 3, wherein the cladding layer comprises:

an under-cladding layer; and

an over-cladding layer, and the core is formed on the under-cladding layer and embedded by the over-cladding layer.

5. The optical waveguide according to claim 2 or 3, wherein the cladding layer has a convex lens formed into virtually a 1/4 arc shape in the cross section at a tip section where light beams are emitted.

6. The optical waveguide according to claim 4, wherein the cladding layer has a convex lens formed into virtually a 1/4 arc shape in the cross section at a tip section where light beams are emitted.

7. An optical touch panel comprising:

a coordinate input region;

an optical waveguide with a light emitting device for generating light beams crossing the coordinate input region;

a light-receiving sided-optical waveguide for receiving the light beams having crossed the coordinate input region; and

light emitting device groups for detecting the intensity of light received at the light-receiving sided-optical waveguide,

wherein the optical waveguide with a light emitting device is the optical waveguide with a light emitting device according to claim 1.