Apparatus and method for a folded optical element waveguide for use with light based touch screens

• US 8,184,108 B2
• Filed: 08/20/2004
• Issued: 05/22/2012
• Est. Priority Date: 06/30/2004
• Status: Expired due to Fees

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: POA Sana Liquidating Trust
• Inventors: Smits, Gerard Dirk
• Primary Examiner(s): Sim, Yong H
• Application Number:
  US10/923,550
• Publication Number:
  US 20060001653A1
• Time in Patent Office: 2,832 Days
• Field of Search: 345/156, 345/14, 345/172, 345/175, 345/173, 345/176, 178/18.09, 178/18.11
• US Class Current: 345/175
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A folded optical element waveguide that allows a minimum width bezel to be used around the perimeter of a light-based touch screen display. The apparatus and method includes a touch screen and a waveguide substrate provided adjacent the touch screen. The waveguide substrate includes a plurality of waveguides and a plurality of optical elements provided adjacent the touch screen. The waveguides include an internally reflective surface to reflect light perpendicular to the surface of the touch screen. The emitting and detecting waveguides are thus folded and provided around the side edges of the display. As a result, the width of the bezel around the display can be minimized.

Claims

1. A method, comprising,

providing a waveguide substrate having a substantially flat upper resting surface bounded, at least in part, by a wall that extends above the resting surface, the wall having a inner surface that is adjacent to the resting surface and an outer surface that is on the opposite side of the wall from the inner surface,

the substrate further comprising a plurality of waveguides arranged on the outer surface of the wall with each waveguide comprising an optical fold that redirects light in the waveguides at a right angle from an originating direction, and

a touch screen arranged on the flat upper resting surface;

and

wherein said providing of the waveguide substrate comprises providing a substrate having the plurality of waveguides arranged in grooves made on the outer surface of the wall thereby comprising a plurality of embedded waveguides each comprising an optical fold that redirects light in the waveguides at said right angle from an originating direction such that the waveguides perform one of;

directing light over the touch screen; and

receiving light from adjacent the touch screen and directing it to a light detector that is not located on the flat upper resting surface.

2. An apparatus, comprising;

a folded waveguide substrate having a top surface and an outer wall that defines an outer vertical wall surface of the substrate, the outer vertical wall surface and the top surface comprising non-parallel surfaces,

a plurality of waveguide grooves contiguously extending along and extending into the outer vertical wall surface and extending into a portion of the top surface of the substrate;

a touch screen arranged on a portion of the top surface of the folded waveguide substrate;

a plurality of contiguous waveguides formed inside the plurality of waveguide grooves to define a pattern of embedded contiguous waveguides, such that each waveguide is in contact with and extends along the outer vertical wall surface and a portion of the top surface of the waveguide substrate, each waveguide comprising,

an optical element formed at a terminal end of the waveguide at the top surface of the waveguide;

an opposing end at an opposite end of the waveguide from said terminal end;

the waveguides further arranged so that each opposing end is optically coupled with one of a light source or a light receiving device; and

said light source or a light receiving device located at a position other than said top surface of the substrate.

3. The apparatus of claim 2 wherein the folded waveguide substrate includes an edge at an interface between the top surface of the substrate and the outer vertical wall surface of the substrate such that the edge defines a right angle between said top surface and outer vertical wall surface of the substrate;

and

wherein each of the contiguous waveguides includes an integral reflective optical element formed in the waveguide at said edge of the substrate enabling light to be reflected from a first direction of travel to a second direction of travel perpendicular to said first direction.

4. The apparatus of claim 2 wherein the folded waveguide substrate further includes an inner wall surface that circumscribes the top surface upon which the touch screen is arranged and wherein the touch screen is arranged on the top surface inside the inner wall surface.

5. The apparatus of claim 3 wherein said integral reflective optical element of said contiguous waveguide comprises a 45 degree angle cut surface arranged to enable light to be reflected in the desired direction in the waveguide.

6. A method, comprising;

providing a waveguide substrate having a substantially flat upper resting surface bounded, at least in part, by a wall that extends above the resting surface, the wall having a inner surface that is adjacent to the resting surface and an outer surface that is on the opposite side of the wall from the inner surface,

the waveguide substrate further including a plurality of waveguides arranged on the outer surface of the wall with each waveguide comprising an optical fold that redirects light in the waveguides at a right angle from an originating direction, and

a touch screen arranged on the flat upper resting surface,

wherein the wall is generally rectangular in shape with the outer vertical wall surface of the wall having four side surfaces and wherein each of said fours sides includes a plurality of grooves made in the side surfaces, the grooves made substantially parallel with the associated side surface in which it is made;

wherein the plurality of waveguides includes subsets of waveguides, with each subset comprising a multiplicity of waveguides that are arranged on a specific one of the four surfaces, each waveguide of said multiplicity of waveguides arranged in the grooves of a corresponding one of said four side surfaces, such that said waveguides lie in the grooves and run substantially parallel with the side surface; and

the optical fold of each subset of waveguides arranged such that said optical fold redirects light in the waveguides in a direction perpendicular to that of the surface on which said waveguides are arranged.