{
  "patent_number": "US 5471515",
  "country": "US",
  "title": "How a Modern Camera Sensor Captures Light and Converts It to Data",
  "original_title": "Active pixel sensor with intra-pixel charge transfer",
  "summary": "This patent describes a camera sensor technology that combines light-capturing elements with a special circuit to read out the image data quickly and efficiently, all on a single chip.",
  "what_it_does": "The patent describes an imaging device, like a digital camera sensor, built on a single silicon chip using a common manufacturing process (CMOS). Each tiny picture element, or \"pixel cell,\" has a photogate (Claim 1) that collects light and turns it into an electrical charge. This charge is then moved within the pixel by a small charge coupled device (CCD) section (Claim 1) to a sensing node. From there, a CMOS readout circuit (Claim 1) with an output field effect transistor (Claim 1) converts the charge into a voltage signal that can be read by the camera. For example, when light hits a pixel, the photogate gathers the light's energy, which is then quickly shifted by the CCD part to the readout circuit, allowing the camera to process the image.",
  "what_it_does_not_cover": [
    "Image sensors that use only traditional CCD technology for both charge collection and readout across the entire chip.",
    "Sensors where the charge is read out directly from the photogate without an intermediate charge coupled device section within the pixel.",
    "Image sensors that do not use a complementary metal oxide semiconductor (CMOS) circuit for the pixel's readout.",
    "Sensors that rely on different charge accumulation mechanisms other than a photogate.",
    "Pixel designs where the charge transfer and readout are handled by entirely separate, off-chip components."
  ],
  "filed": "1994-01-28",
  "granted": "1995-11-28",
  "expires": "2014-01-28",
  "status": "expired",
  "holder": "California Institute of Technology",
  "holder_url": "https://patentbrief.org/company/california-institute-of-technology",
  "inventors": [
    {
      "name": "Eric R. Fossum",
      "url": "https://patentbrief.org/inventor/eric-r-fossum"
    },
    {
      "name": "Sunetra Mendis",
      "url": "https://patentbrief.org/inventor/sunetra-mendis"
    },
    {
      "name": "Sabrina E. Kemeny",
      "url": "https://patentbrief.org/inventor/sabrina-e-kemeny"
    }
  ],
  "times_cited": 620,
  "tags": [
    "consumer_electronics",
    "semiconductors",
    "telecommunications",
    "automotive",
    "software"
  ],
  "abstract": "An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.",
  "url": "https://patentbrief.org/patent/us/5471515/cmos-active-pixel-image-sensor",
  "markdown_url": "https://patentbrief.org/patent/us/5471515/cmos-active-pixel-image-sensor/md",
  "google_patents_url": "https://patents.google.com/patent/US5471515",
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}