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[Patent] New Canon Phase-Detection AF Method With Higher Accuracy And Smaller Pixel Size (for the next mirrorless camera?)

Egami (machine translated) found a Canon patent for an improved phase-detection AF. Higher accuracy is obtained by better propagation of light. The patent text also suggests, the method should improve accuracy when light is falling in with a low-angle incident. I found another thing very interesting: the patent refers to smaller pixel size, i.e. you can pack more pixel on the sensor. So, given that a phase-detection AF is particularly useful on a mirrorless camera, could that indicate that Canon is working on a higher resolutions sensor (with an improved AF) for its more pro-oriented mirrorless camera that we expect to be announced later this year?

  • Patent Publication No. 2012-151215
    • 2012.8.9 Release Date
    • 2011.1.18 filing date
  • Existing techniques
    • JP 2002-314062
    • Conventional techniques beam separation is insufficient, Ranging Accuracy is poor
      • Scattering effects due to wiring
      • The smaller the angle of incidence, it is difficult to detect
      • Smaller pixel size, the value of F becomes larger microlenses (dark), they spread the light next to almost the same in the size of the image pixel size and pixel diffraction
  • And waveguide
    • The waveguide, depending on the angle of incidence of the light flux, there is a characteristic (waveguide mode) is different states of light propagation in the waveguide
  • Canon ‘s patented
    • Consisting of waveguide waveguide and vice
      • Guiding light of two different incident direction: waveguide
      • Vice waveguide: one for each waveguide comprises a waveguide two sub-
    • Can be detected by the photoelectric conversion unit specific, the incident light at a particular angle
    • Impact of wiring
      • The incident light to propagate the core portion of the waveguide, reducing the impact of wiring
    • Low-angle incident light, by using the corresponding waveguide mode depends on the incident direction
    • Small pixel size, support by limiting the distribution of the emitted light
      • Achieved by suppressing the spatial width confinement in the waveguide propagation of light sub-


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