# US 11,029,783 B2 · Optical touch system comprising means for projecting and detecting light beams above and inside a transmissive panel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,783 B2 - Document ID: US11029783B2 - Status: Granted - Kind: B2 - Application number: 16/666,013 - Filed: 2019-10-28 - Published: 2020-06-25 - Granted: 2021-06-08 - Earliest claimed: 2015-02-09 - Assignees: FlatFrog Laboratories AB - Applicants: FlatFrog Laboratories AB - Inventors: Ola Wassvik; Håkan Bergström; Ivan Karlsson; Thomas Craven-Bartle - Web page: https://patentgrep.com/patent/US11029783B2 ## CPC - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - G06F 1/3231: Monitoring the presence, absence or movement of users - G06F 1/3262: {Power saving in digitizer or tablet} - G06F 3/0428: {by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual (sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421)} - G06F 2203/04102: Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper - G06F 2203/04104: Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger - G06F 2203/04106: Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection - G06F 2203/04108: Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction - 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 - Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract An embodiment of the invention provides a touch sensing apparatus, comprising: a light transmissive element (10) that defines a touch surface; a set of emitters (30a) arranged around the periphery of the touch surface to emit beams of light into the light transmissive element, wherein a first portion of the beams (50) of light propagate inside the light transmissive element while illuminating the touch surface such that an object touching the touch surface causes an attenuation of the propagating light, and wherein a second portion of the beams (90) of light pass out of the light transmissive element and are reflected to travel above the touch surface, a set of light detectors (30b) arranged around the periphery of the touch surface to receive light from the set of emitters from the transmissive element and from above the touch surface, wherein each light detector is arranged to receive light from more than one emitter. ## Claims ### Claim 1 A touch sensing apparatus, comprising: a panel having a touch surface and a bottom surface; a plurality of emitters arranged around a portion of the periphery of the touch surface to emit beams of light; a diffusive reflecting surface of a non-transmissive frame component arranged around a portion of the periphery of the touch surface, said diffusive reflecting surface configured to spread out the emitted beams of light across the touch surface and form overlapping detection lines; said diffusive reflecting surface comprising a first edge proximal to a plane of the touch surface and a second edge distal to the plane of the touch surface, and wherein the second edge is closer to a center point of the touch surface than the first edge such that the diffusive reflecting surface forms an acute angle with the touch surface, a plurality of light detectors arranged around a portion of the periphery of the touch surface, said plurality of light detectors configured to receive light from the plurality of emitters, wherein each of the plurality of light detector is arranged to receive light from more than one of the plurality of emitters; and a processing element configured to determine, based on output signals generated from the plurality of light detectors, a position of an object on the touch surface. ### Claim 2 (depends on 1) The touch sensing apparatus of claim 1, wherein the diffusive reflecting surface is arranged above the touch surface and the plurality of emitters is arranged below the bottom surface. ### Claim 3 (depends on 1) The touch sensing apparatus according to claim 1, wherein the plurality of emitters is arranged along a first edge at the periphery, and wherein the diffusive reflecting surface is arranged along the first edge to direct the beams of light emitted from the plurality of emitters across the touch surface to a diffusive reflecting surface arranged at an opposite edge at the periphery. ### Claim 4 (depends on 3) The touch sensing apparatus according to claim 3, wherein the diffusive reflecting surface at the opposite edge directs the light onto detectors arranged along the opposite edge. ### Claim 5 (depends on 1) The touch sensing apparatus according to claim 1, wherein the plurality of detectors is arranged below the bottom surface. ### Claim 6 (depends on 1) The touch sensing apparatus according to claim 1, wherein the diffusive reflecting surface is arranged so that a portion of the light directed across the touch surface is reflected off the touch surface. ### Claim 7 (depends on 1) The touch sensing apparatus according to claim 1, wherein the panel is curved to form a concave surface. ### Claim 8 (depends on 7) The touch sensing apparatus according to claim 7, wherein the diffusive reflecting surface is arranged so that a portion of the light directed across the touch surface is reflected a plurality of times off the touch surface. ### Claim 9 (depends on 1) The touch sensing apparatus according to claim 1, comprising a dust shield arranged above the touch surface, wherein the dust shield forms a sloping edge. ### Claim 10 (depends on 1) The touch sensing apparatus according to claim 1, wherein the diffusive reflecting surface is a Lambertian diffusive reflecting surface. ### Claim 11 (depends on 1) The touch sensing apparatus according to claim 1, wherein the diffusive reflecting surface comprises a titanium oxide layer. ### Claim 12 (depends on 1) The touch sensing apparatus according to claim 1, wherein the panel is a light transmissive panel, and wherein the light from the emitters is transmitted to the diffusive reflecting surface through the light transmissive panel.