{
  "patent_number": "US 5825352",
  "country": "US",
  "title": "Logitech's Method for Using Two Fingers on a Touchpad",
  "original_title": "Multiple fingers contact sensing method for emulating mouse buttons and mouse operations on a touch sensor pad",
  "summary": "Logitech's 1998 patent describes how a touchpad can detect two fingers touching it in a specific sequence to perform actions like clicking or dragging, going beyond single-finger mouse emulation.",
  "what_it_does": "This patent explains a way for a touchpad to understand when two fingers are touching it, not just one. It works by scanning the touchpad to find a strong signal (a 'maxima') from a first finger, then a dip (a 'minima'), and then another strong signal from a second finger. When it finds this pattern of two strong signals separated by a dip, it knows two fingers are present. This allows the touchpad to do more than just move a cursor; it can trigger actions like a mouse click (Claim 2), a 'drag' function (Claim 3, 11), or a 'select' function (Claim 4) based on how the fingers are used and their proximity (Claim 8, 15). For example, if two fingers touch down in this sequence, it could initiate a drag operation.",
  "what_it_does_not_cover": [
    "Detecting only one finger touching the sensor.",
    "Detecting multiple fingers without the specific sequence of two maxima separated by a minima.",
    "Touch sensors that do not scan to identify signal maxima and minima.",
    "Emulating mouse buttons or operations without detecting two fingers.",
    "Functions triggered by gestures that don't involve the specific two-finger maxima/minima pattern."
  ],
  "filed": "1996-02-28",
  "granted": "1998-10-20",
  "expires": "2016-02-28",
  "status": "expired",
  "holder": "Logitech Inc",
  "holder_url": "https://patentbrief.org/company/logitech-inc",
  "inventors": [
    {
      "name": "Bernard Kasser",
      "url": "https://patentbrief.org/inventor/bernard-kasser"
    },
    {
      "name": "Stephen J. Bisset",
      "url": "https://patentbrief.org/inventor/stephen-j-bisset"
    }
  ],
  "times_cited": 1577,
  "tags": [
    "consumer_electronics",
    "software",
    "semiconductors"
  ],
  "abstract": "Method and apparatus for detecting an operative coupling between one or more fingers or other appropriate objects and a touch pad includes processes for detection of multiple maxima with intermediate minima in appropriate sequences to emulate the operations of cursor control and button actuations in a pointing and control device.",
  "url": "https://patentbrief.org/patent/us/5825352/apple-pinch-to-zoom",
  "markdown_url": "https://patentbrief.org/patent/us/5825352/apple-pinch-to-zoom/md",
  "google_patents_url": "https://patents.google.com/patent/US5825352",
  "relatedPatents": [
    {
      "patentNumber": "6323846",
      "countryCode": "US",
      "title": "How a Multi-Touch Screen Detects Multiple Fingers and Palms",
      "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": "7812826",
      "countryCode": "US",
      "title": "How Multi-Touch Gestures Like Pinch-to-Zoom Work on Smartphones",
      "url": "https://patentbrief.org/patent/us/7812826/iphone-software-keyboard"
    },
    {
      "patentNumber": "7663607",
      "countryCode": "US",
      "title": "How Multi-Touch Screens Track Multiple Fingers at Once",
      "url": "https://patentbrief.org/patent/us/7663607/multipoint-touchscreen"
    },
    {
      "patentNumber": "7812828",
      "countryCode": "US",
      "title": "How Touchscreens Use Math to Recognize Your Fingers",
      "url": "https://patentbrief.org/patent/us/7812828/ellipse-fitting-for-multi-touch-surfaces"
    }
  ]
}