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Canon patent for improved phase-detection AF (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. Another fact is 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? I think that’s plausible. If Canon is working on a mirrorless camera that is more pro-oriented than the EOS M, this cam will most probably have a higher resolution.

  • 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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