# US 10,481,735 B2 · Augmented optical waveguide for use in an optical touch sensitive device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,735 B2 - Document ID: US10481735B2 - Status: Granted - Kind: B2 - Application number: 15/821,572 - Filed: 2017-11-22 - Published: 2018-05-24 - Granted: 2019-11-19 - Earliest claimed: 2012-07-24 - Assignees: Rapt IP Limited - Applicants: Rapt IP Limited - Inventors: Owen Drumm; Julien Piot; Robert Copperwhite - Web page: https://patentgrep.com/patent/US10481735B2 ## CPC - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - G06F 3/0308: {comprising a plurality of distinctive and separately oriented light emitters or reflectors associated to the pointing device, e.g. remote cursor controller with distinct and separately oriented LEDs at the tip whose radiations are captured by a photo-detector associated to the screen} - G06F 2203/04103: Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices - G06F 2203/04107: Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds - G06F 2203/04109: FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An optical touch-sensitive device is able to determine the locations of multiple simultaneous touch events. The optical touch-sensitive device includes multiple emitters and detectors coupled with an optical coupler assembly through a waveguide on the surface on the optical-touch sensitive device. Each emitter produces optical beams which propagate in the waveguide via total internal reflection and are received by the detectors. Touch events disturb the optical beams, and are determined based on the disturbances. The waveguide has at least one dead zone on its surface. The dead zone is formed with a cover layer having a top surface and a bottom surface where the bottom surface of the cover layer is directly coupled to the top surface of the waveguide. The cover layer preserves optical beam propagation in the waveguide and makes the dead zone insensitive to touches on the top surface of the cover layer. ## Claims ### Claim 1 An optical touch-sensitive device for use with a display, the touch-sensitive device comprising: a planar optical waveguide extending over a surface of the display, the waveguide having a top surface and a bottom surface; emitters and detectors arranged along a periphery of the display; an optical coupler assembly positioned along the periphery of the display, the optical coupler assembly coupling optical beams produced by the emitters into the waveguide and out of the waveguide to the detectors, wherein touches on the top surface of the waveguide disturb the optical beams, the touch-sensitive device determining touch events based on the disturbances; and at least one static dead zone, the static dead zone comprising: a cover layer having a top surface and a bottom surface, the bottom surface of the cover layer directly coupled to the top surface of the waveguide, the cover layer preserving optical beam propagation in the waveguide by reflecting optical beams propagating in the waveguide at the cover layer's bottom surface, wherein the cover layer makes the dead zone insensitive to touches; and a dark layer that is opaque to visible light, wherein a bottom surface of the dark layer is coupled to the top surface of the cover layer. ### Claim 2 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer is transparent to visible light. ### Claim 3 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer has a thickness greater than at least a penetration depth of an evanescent light field in the waveguide. ### Claim 4 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer is a low refractive index layer that has a refractive index smaller than the refractive index of the waveguide. ### Claim 5 (depends on 4) The optical touch-sensitive device of claim 4, wherein the thickness of the cover layer is in the range 1 micron to 50 microns. ### Claim 6 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer has one or more gaps. ### Claim 7 (depends on 1) The optical touch-sensitive device of claim 1, wherein the waveguide comprises a single plane of material. ### Claim 8 (depends on 1) The optical touch-sensitive device of claim 1, further comprising at least one fixed graphics zone for displaying fixed graphics, each fixed graphics zone comprising: an ink layer opaque to visible light, the ink layer comprising the fixed graphics, the optical touch-sensitive device performing pre-defined functions corresponding to touches on the top surface of the waveguide aimed at the fixed graphics; and an additional cover layer interposed between the bottom surface of the waveguide and the ink layer, the additional cover layer of the fixed graphics zone preserving optical beam propagation in the waveguide and transparent to visible light. ### Claim 9 (depends on 1) The optical touch-sensitive device of claim 1, wherein the optical coupler assembly redirects light rays entering into the waveguide from an emitter or exiting from the waveguide and entering a detector. ### Claim 10 (depends on 1) The optical touch-sensitive device of claim 1, further comprising a binding layer physically coupling the optical coupler assembly to the waveguide, the binding layer comprising an optically clear adhesive that is transparent to optical beams propagating in the waveguide. ### Claim 11 (depends on 1) The optical touch-sensitive device of claim 1, wherein the optical beams have infrared wavelengths ranging from 200 nm to 2000 nm. ### Claim 12 (depends on 1) The optical touch-sensitive device of claim 1, further comprising: an intermediate layer interposed between the bottom surface of the waveguide and the surface of the display, the intermediate layer preserving optical beam propagation in the waveguide and being transparent to visible light. ### Claim 13 (depends on 12) The optical touch-sensitive device of claim 12, wherein the optical coupler assembly and the waveguide are optically coupled such that light passes from the optical coupler assembly to the waveguide without interacting with the intermediate layer. ### Claim 14 (depends on 13) The optical touch-sensitive device of claim 13, wherein the intermediate layer has a refractive index smaller than a refractive index of the waveguide, and optical beam propagation in the waveguide is preserved via total internal reflection at the bottom surface of the waveguide. ### Claim 15 (depends on 14) The optical touch-sensitive device of claim 14, further comprising a binding layer physically coupling the intermediate layer to the display, the binding layer transparent to visible light. ### Claim 16 (depends on 14) The optical touch-sensitive device of claim 14, wherein the intermediate layer has a thickness greater than at least a penetration depth of an evanescent light field in the waveguide. ### Claim 17 (depends on 14) The optical touch-sensitive device of claim 14, wherein the intermediate layer comprises a fluoropolymer material. ### Claim 18 (depends on 14) The optical touch-sensitive device of claim 14, wherein the optical coupler assembly and the waveguide are optically coupled such that light passes through the intermediate layer when being coupled from the emitters into waveguide and from the waveguide into the detectors. ### Claim 19 (depends on 14) The optical touch-sensitive device of claim 14, wherein the intermediate layer functions as a binding layer physically coupling the waveguide to the display. ### Claim 20 (depends on 12) The optical touch-sensitive device of claim 12, wherein the intermediate layer is a mirror for the optical beams propagating in the waveguide, and optical beam propagation in the waveguide is preserved via specular reflection at the bottom surface of the waveguide. ### Claim 21 (depends on 20) The optical touch-sensitive device of claim 20, wherein the intermediate layer is a holographic film. ### Claim 22 (depends on 20) The optical touch-sensitive device of claim 20, wherein the intermediate layer is an interference filter. ### Claim 23 (depends on 12) The optical touch-sensitive device of claim 12, wherein the optical coupler assembly is transparent to the optical beams propagating in the waveguide and is opaque to visible light. ### Claim 24 (depends on 23) The optical touch-sensitive device of claim 23, wherein a coupling surface of the optical coupler assembly that couples to the waveguide extends to an edge of the bottom surface of the waveguide. ### Claim 25 (depends on 23) The optical touch-sensitive device of claim 23, further comprising a dark ink layer positioned such that an edge portion of the intermediate layer is interposed between the dark ink layer and the bottom surface of the waveguide, the dark ink layer opaque to visible light. ### Claim 26 (depends on 12) The optical touch-sensitive device of claim 12, further comprising an ink layer interposed between the optical coupler assembly and the waveguide, the ink layer transparent to the optical beams propagating in the waveguide and opaque to visible light. ### Claim 27 (depends on 26) The optical touch-sensitive device of claim 26, wherein the ink layer extends to an edge of the bottom surface of the waveguide. ### Claim 28 (depends on 26) The optical touch-sensitive device of claim 26, wherein the ink layer extends to overlap with an edge portion of the intermediate layer. ### Claim 29 (depends on 26) The optical touch-sensitive device of claim 26, further comprising a dark ink layer positioned such that the ink layer and an edge portion of the intermediate layer are interposed between the dark ink layer and the bottom surface of the waveguide, the dark ink layer opaque to visible light. ### Claim 30 (depends on 26) The optical touch-sensitive device of claim 26, further comprising a dark ink layer positioned such that an edge portion of the intermediate layer is interposed between the ink layer and the dark ink layer and the ink layer is interposed between the bottom surface of the waveguide and the edge portion of the intermediate layer, the dark ink layer opaque to visible light. ### Claim 31 (depends on 12) The optical touch-sensitive device of claim 12, further comprising a dark layer positioned such that a bottom surface of the dark layer is directly coupled to the top surface of the cover layer, the dark layer comprising a dark material opaque to visible light. ### Claim 32 (depends on 31) The optical touch-sensitive device of claim 31, further comprising a protective layer positioned such that a bottom surface of the protective layer is directly coupled to a top surface of the dark layer, the protective layer transparent to visible light. ### Claim 33 (depends on 12) The optical touch-sensitive device of claim 12, further comprising: at least one fixed graphics zone for displaying fixed graphics, each fixed graphics zone comprising: an ink layer opaque to visible light, the ink layer comprising the fixed graphics, the optical touch-sensitive device performing pre-defined functions corresponding to touches on the top surface of the waveguide aimed at the fixed graphics; and an additional intermediate layer interposed between the bottom surface of the waveguide and the ink layer, the additional intermediate layer of the fixed graphics zone preserving optical beam propagation in the waveguide and transparent to visible light. ### Claim 34 (depends on 12) The optical touch-sensitive device of claim 12, further comprising: at least one frame zone, each frame zone comprising: an ink layer opaque to visible light; and an additional intermediate layer interposed between the bottom surface of the waveguide and the ink layer, the additional intermediate layer of the frame zone preserving optical beam propagation in the waveguide and transparent to visible light. ### Claim 35 (depends on 12) The optical touch-sensitive device of claim 12, wherein the optical coupler assembly is a multi-part assembly, a first part of the optical coupler assembly is positioned underneath the bottom surface of the waveguide within and surrounded by the intermediate layer and a second part of the optical coupler assembly is positioned underneath the intermediate layer. ### Claim 36 (depends on 35) The optical touch-sensitive device of claim 35, wherein the optical coupler assembly has a refractive index that is close to or substantially matched with a refractive index of the intermediate layer. ### Claim 37 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer is a low-RI layer. ### Claim 38 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer is applied to the waveguide using a lamination process. ### Claim 39 (depends on 1) The optical touch-sensitive device of claim 1, wherein the cover layer is a mirror layer. ### Claim 40 (depends on 1) The optical touch-sensitive device of claim 1, wherein the at least one static dead zone further comprises: a protective layer that is transparent to visible light, wherein a bottom surface of the protective layer is coupled to a top surface of the dark layer.