{
  "patent_number": "US 5961804",
  "country": "US",
  "title": "Tiny Capsules for Electronic Paper Displays",
  "original_title": "Microencapsulated electrophoretic display",
  "summary": "MIT's 1999 patent on a special ink made of tiny capsules that can change color when an electric field is applied, forming the basis for early e-readers.",
  "what_it_does": "This patent describes a material for electronic displays, like early e-readers. It's an 'electrophoretic material' made of a carrier liquid holding many tiny capsules, called microcapsules. Inside each microcapsule are particles that can move when an electric field is applied. Some particles are designed to reflect light better, making them appear bright. Others might be colored or even emit light. The key is that these particles can be moved to show different colors or patterns, and importantly, they stay that way even after the electric field is turned off. This 'bistability' is what makes it work like paper, holding an image without constant power. For example, imagine a microcapsule with black particles and white reflective particles. Applying a field can push the white particles to the front, making the capsule look white, or push the black particles forward, making it look black.",
  "what_it_does_not_cover": [
    "Materials that require continuous power to maintain their displayed image.",
    "Displays where the particles do not have differential responsiveness to an electric field.",
    "Microcapsules that do not contain multiple phases or particles with contrasting visual properties.",
    "Materials where the visual appearance does not persist after the electric field is removed.",
    "Displays that rely solely on light emission without reflective elements for their appearance."
  ],
  "filed": "1997-03-18",
  "granted": "1999-10-05",
  "expires": "2017-03-18",
  "status": "expired",
  "holder": "Massachusetts Institute of Technology",
  "holder_url": "https://patentbrief.org/company/massachusetts-institute-of-technology",
  "inventors": [
    {
      "name": "Joseph Jacobson",
      "url": "https://patentbrief.org/inventor/joseph-jacobson"
    },
    {
      "name": "Barrett Comiskey",
      "url": "https://patentbrief.org/inventor/barrett-comiskey"
    },
    {
      "name": "Jonathan Albert",
      "url": "https://patentbrief.org/inventor/jonathan-albert"
    }
  ],
  "times_cited": 508,
  "tags": [
    "consumer_electronics",
    "semiconductors",
    "materials",
    "telecommunications"
  ],
  "abstract": "An application-ready electrophoresis material includes a carrier and a dispersion of microcapsules therein, the microcapsules each containing a plurality of phases therein. At least some of the phases contrast visually and and exhibit differential responsiveness to an electric field, such that application of the field determines the visual appearance of the microcapsules. The material exhibits stability such the visual appearance persists despite removal of the field. In one aspect, the invention provides for enhanced stability of the visual appearance. In another aspect, the reflectivity of at least one of the phases is enhanced. In another aspect, one of the phases is particulate in nature and emits visible radiation.",
  "url": "https://patentbrief.org/patent/us/5961804/e-ink-electronic-paper-display",
  "markdown_url": "https://patentbrief.org/patent/us/5961804/e-ink-electronic-paper-display/md",
  "google_patents_url": "https://patents.google.com/patent/US5961804",
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}