{
  "patent_number": "US 3672155",
  "country": "US",
  "title": "Hamilton's Early Digital Watch with LED Display",
  "original_title": "Solid state watch",
  "summary": "Hamilton's 1972 patent for a digital watch that uses electronic circuits and light-emitting diodes (LEDs) to show time, instead of gears and hands, powered by a rechargeable battery.",
  "what_it_does": "This patent describes a digital watch with no moving parts for telling time. It uses a crystal-controlled oscillator to create precise timing signals. These signals are then processed by an integrated circuit that divides the frequency and drives light-emitting diodes (LEDs). The LEDs form a digital display, showing hours, minutes, and seconds in base-ten numbers. A key feature is a 'demand switch' that only turns on the LEDs when pressed, saving battery power. Another innovation is an ambient light sensor that adjusts the brightness of the LEDs based on surrounding light conditions. The whole system is powered by a rechargeable battery.",
  "what_it_does_not_cover": [
    "Watches that use mechanical gears and hands to display time.",
    "Watches that use analog displays instead of digital numbers.",
    "Watches that do not have a crystal-controlled oscillator for timing.",
    "Watches that do not use light-emitting diodes for display.",
    "Watches where the display is always on without a demand switch.",
    "Watches that do not adjust display brightness based on ambient light."
  ],
  "filed": "1970-05-06",
  "granted": "1972-06-27",
  "expires": "1990-05-06",
  "status": "expired",
  "holder": "Hamilton Watch Co",
  "holder_url": "https://patentbrief.org/company/hamilton-watch-co",
  "inventors": [
    {
      "name": "John M Bergey",
      "url": "https://patentbrief.org/inventor/john-m-bergey"
    },
    {
      "name": "Richard S Walton",
      "url": "https://patentbrief.org/inventor/richard-s-walton"
    }
  ],
  "times_cited": 118,
  "tags": [
    "consumer_electronics",
    "semiconductors",
    "software"
  ],
  "abstract": "Disclosed is a solid state watch which requires no moving parts for timekeeping and display. The watch comprises a crystal controlled oscillator connected through an integrated circuit binary frequency divider to an electro-optical display in the form of light emitting diodes. The display is energized only on demand and the level of the light output is controlled in accordance with ambient light conditions. The watch is energized from a rechargeable battery.",
  "url": "https://patentbrief.org/patent/us/3672155/digital-watch-pulsar",
  "markdown_url": "https://patentbrief.org/patent/us/3672155/digital-watch-pulsar/md",
  "google_patents_url": "https://patents.google.com/patent/US3672155",
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}