{
  "patent_number": "US 20110205189",
  "country": "US",
  "title": "How Optical Sensors Find Multiple Touches on a Screen",
  "original_title": "Stereo Optical Sensors for Resolving Multi-Touch in a Touch Detection System",
  "summary": "This patent describes a system that uses at least two pairs of light sensors and clever math to accurately figure out where multiple fingers are touching a screen, even when shadows overlap.",
  "what_it_does": "The system uses light emitters to shine energy across a touch area. When a finger touches the screen, it casts shadows. A first pair of optical sensors detects these shadows and, using triangulation, figures out a \"first set of potential points\" where touches might be (Claim 1). A second pair of optical sensors does the same, creating a \"second set of potential points\" (Claim 1). A computer then compares these two sets, looking for pairs of potential points that are very close to each other. The pairs with the shortest distances are identified as the actual \"true touch points\" (Claim 1). For example, if two fingers touch a screen, each pair of sensors might initially see several possible touch locations, but only the actual touch points will be consistently identified by both sensor pairs as very close together.",
  "what_it_does_not_cover": [
    "Touch detection systems that rely on electrical properties, like capacitive touchscreens.",
    "Single-touch systems, as the claims specifically address \"multitouch scenarios\" and \"multiple true touch points\" (Claim 1).",
    "Systems that use only one pair of optical sensors for touch detection.",
    "Touchscreens that do not use optical emitters and sensors to detect shadows.",
    "Methods for resolving multitouch that do not involve comparing potential points from at least two distinct sensor pairs and calculating distances."
  ],
  "filed": "2009-09-29",
  "granted": null,
  "expires": "2029-09-29",
  "status": "active",
  "holder": "Individual",
  "holder_url": "https://patentbrief.org/company/individual",
  "inventors": [
    {
      "name": "John David Newton",
      "url": "https://patentbrief.org/inventor/john-david-newton"
    }
  ],
  "times_cited": 34,
  "tags": [
    "consumer_electronics",
    "software",
    "telecommunications",
    "semiconductors"
  ],
  "abstract": "An optical touch detection system including at least two stereo pairs of optical sensors, which are identify a set of potential points, and methods for determining which of the potential points are true touch points. The first pair of optical sensors is used to identify a first set of potential points and the second set of optical sensors is used to identify a second set of potential points. Potential point pairs are then compared as between the first and second sets of potential points, i.e., each potential point pair includes a potential point from the first set and a potential point from the second set. Each potential point pair is evaluated to determine the distance between its constituent potential points. The true touch points are identified by selecting the potential point pairs having the shortest distances between their constituent potential points. Using at least two pairs of optical sensors reduces the total number of potential point pairs that must be evaluated to determine the true touch points necessary computational analysis.",
  "url": "https://patentbrief.org/patent/us/20110205189/stereo-optical-sensors-for-resolving-multi-touch-in-a-touch-detection-system",
  "markdown_url": "https://patentbrief.org/patent/us/20110205189/stereo-optical-sensors-for-resolving-multi-touch-in-a-touch-detection-system/md",
  "google_patents_url": "https://patents.google.com/patent/US20110205189",
  "relatedPatents": [
    {
      "patentNumber": "20110234542",
      "countryCode": "US",
      "title": "Using Different Light Colors to Detect Touches on Screens",
      "url": "https://patentbrief.org/patent/us/20110234542/methods-and-systems-utilizing-multiple-wavelengths-for-position-detection"
    },
    {
      "patentNumber": "7355593",
      "countryCode": "US",
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      "url": "https://patentbrief.org/patent/us/7355593/xbox-360-controller"
    },
    {
      "patentNumber": "6323846",
      "countryCode": "US",
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      "url": "https://patentbrief.org/patent/us/6323846/aqua-user-interface"
    },
    {
      "patentNumber": "8619056",
      "countryCode": "US",
      "title": "How Touchscreens Tell Real Touches From False Ghost Touches",
      "url": "https://patentbrief.org/patent/us/8619056/ghost-resolution-for-a-capacitive-touch-panel"
    },
    {
      "patentNumber": "5825352",
      "countryCode": "US",
      "title": "Logitech's Method for Using Two Fingers on a Touchpad",
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    }
  ]
}