Canon’s labs are actively working on hybrid viewfinder technology. This is not the first patent referring to this very technology.

The new patent is patent JP2017-146322A, The patent’s abstract says:

PROBLEM TO BE SOLVED: To solve problems of an increased size, a complicated mechanism and the like of a camera employing a viewfinder device allowing switching between an optical viewfinder (OVF) and an electronic viewfinder (EVF).
SOLUTION: A main mirror that directs a subject image from a lens to a viewfinder and performs reciprocating revolving movement between a subject observation position and an image pick-up position in which an image pick-up device receives light of the subject image from the lens is configured to have both a display function to display, e.g., an image picked up by the image pick-up device and a mirror function to direct the subject image to the viewfinder, thereby realizing: an OVF mode in which the subject image on a reticle is observed with the viewfinder using the mirror function of the main mirror; and an EVF mode in which the main mirror is in an up state and a live view image of the subject is displayed by the display function of the main mirror and observed with the viewfinder.

If you like “patentish language”, you may want to dive into the patent’s claims:

[Claim 1] A main mirror (4) which carries out the both-way rotational movement of the object image from an object observation position and a lens (2) which leads an object image from a lens (2) to a finder between image pickup positions which carry out light reception to an image sensor (17),
It constitutes so that it may have a display function (6) which displays a taken image of an image sensor (17), and a function of a mirror which leads an object image to a finder,
OVF mode in which an object image on a reticle (11) is observed with a finder using a mirror function (5) of a main mirror (4),
A finder device of a camera having the EVF mode which changes a main mirror (4) into a rise state, displays a live view image of an object by a display function (6) of a main mirror (4), and it observes with a finder.
[Claim 2] A finder device of the camera according to claim 1 using the aforementioned display function as a transparent display device (6) which used an EL element.
[Claim 3] A finder device of the camera according to claim 1, wherein a mirror function of the aforementioned main mirror (4) will comprise a modulated light mirror which changes reflectance and will be in a transmission state in EVF mode with impressed electromotive force.
[Claim 4] It is a main mirror (104) which carries out the both-way rotational movement of the object image from an object observation position and a lens (2) which leads an object image from a lens (2) to a finder between image pickup positions which carry out light reception to an image sensor (17),
When it evacuates to an image pickup position, it has a gobo (109) for plugging up an opening on the back surface side of the main mirror (104),
A display part (106) which displays a taken image of an image sensor (17) on a surface on the main mirror (104) side of the gobo (109) is provided,
OVF mode in which lead an object image from a lens (2) to a finder by a main mirror (104), and it observes an object,
A finder device of a camera having the EVF mode which displays a live view image of an object on a display part (106) provided to the aforementioned gobo (109) in the state of the rise of a main mirror (104), and it observes with a finder.
[Claim 5] A finder device of the camera according to claim 4, wherein the aforementioned main mirror (104) will comprise a modulated light mirror which changes reflectance and will be in a transmission state in EVF mode with impressed electromotive force.
[Claim 6] A finder device of the camera according to any one of claims 1 to 5 switching the aforementioned OVF mode and the aforementioned EVF mode, and observing an object.

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