	US 12,242,083 B2
	Optical unit, optical device, and image display system
Masahiro Mizuta, Yokohama (JP); Ryoichi Sataka, Yokohama (JP); and Tomohiro Kawasaki, Saitama (JP)
Assigned to NIKON CORPORATION, Tokyo (JP)
Filed by NIKON CORPORATION, Tokyo (JP)
Filed on Jun. 4, 2021, as Appl. No. 17/338,850.
Application 17/338,850 is a continuation of application No. PCT/JP2018/044780, filed on Dec. 5, 2018.
Prior Publication US 2021/0294117 A1, Sep. 23, 2021
Int. Cl. G02B 30/36 (2020.01); A61B 3/13 (2006.01)

CPC G02B 30/36 (2020.01) [A61B 3/13 (2013.01)]

16 Claims

1. An optical unit comprising:

an optical system that includes a focal point on a light incident side at a position for setting a display image of an object and that is configured to emit light from a focal plane as parallel light; and

a housing section housing the optical system;

the optical unit being configured so as to satisfy a condition equation expressed by

IB≥7570 mm³

wherein IB is a viewable area where the display image is viewable,

wherein the viewable area is derived based on an effective diameter of a lens included in the optical system and based on an angle formed between a chief light ray at a maximum angle of view and an optical axis of the optical system, and

wherein the viewable area is formed so as to satisfy a condition equation expressed by

ω≤50°

wherein ω is the angle formed between the chief light ray at the maximum angle of view in the optical system and the optical axis of the optical system.