{
  "patent_number": "US 5181252",
  "country": "US",
  "title": "How Bose Prevents Noise-Canceling Headphones From Breaking During Loud Sounds",
  "original_title": "High compliance headphone driving",
  "summary": "A 1993 Bose patent describing a physical design for noise-canceling headphones that prevents the speaker diaphragm from collapsing or popping out of place during intense audio pressure.",
  "what_it_does": "This patent describes a way to make noise-canceling headphones more durable when dealing with high-pressure sound waves. Because active noise reduction systems often use very flexible (high compliance) speaker diaphragms, these parts can easily be pushed too far, causing the voice coil to pop out of its magnetic gap or the diaphragm to get stuck in a collapsed state. The invention adds physical limiters, such as plastic elements or wire mesh screens, to stop the diaphragm from moving beyond a safe distance. It also includes specific shapes or indentations in the diaphragm material that act like a spring, ensuring the speaker snaps back to its original shape if it ever gets squashed.",
  "what_it_does_not_cover": [
    "Does not cover the electronic noise-cancellation algorithms (the 'active' part of the system).",
    "Does not cover standard headphones that lack the high-compliance diaphragm design.",
    "Does not cover software-based limiters or digital signal processing (DSP) used to cap volume.",
    "Does not cover non-mechanical methods for preventing diaphragm damage."
  ],
  "filed": "1991-10-16",
  "granted": "1993-01-19",
  "expires": null,
  "status": "active",
  "holder": "Bose Corp",
  "holder_url": "https://patentbrief.org/company/bose-corp",
  "inventors": [
    {
      "name": "John J. Breen",
      "url": "https://patentbrief.org/inventor/john-j-breen"
    },
    {
      "name": "Roman Sapiejewski",
      "url": "https://patentbrief.org/inventor/roman-sapiejewski"
    }
  ],
  "times_cited": 54,
  "tags": [
    "consumer_electronics",
    "mechanical"
  ],
  "abstract": "An active noise reducing headset has a high compliance diaphragm. Structure limits the maximum excursion of the diaphragm so that the voice coil does not escape the air gap. Structure, such as indentations in the diaphragm, prevent unrecoverable diaphragm collapse.",
  "url": "https://patentbrief.org/patent/us/5181252/acoustic-noise-cancelling",
  "markdown_url": "https://patentbrief.org/patent/us/5181252/acoustic-noise-cancelling/md",
  "google_patents_url": "https://patents.google.com/patent/US5181252",
  "relatedPatents": []
}