Interesting patent that seems to refer to how Canon increased the coverage of Auto-Focus points in the new Canon EOS 5D Mark IV. The image above shows the difference compared to the EOS 5D Mark III. It’s done by replacing the sub mirrors with laminated diffraction gratings, as in the image below. The laminated gratings alter the reflection angle.
- Patent Publication No. 2016-142769
- Published 2016.8.8
- Filing date 2015.1.30
- Canon patent
- Sub-mirror constituted by the reflection type laminated diffraction grating
- AF mirror constituted by the reflection type laminated diffraction grating