Optical viewing device for head-up display or helmet-mounted display e.g. for aircraft pilot

摘要

The device uses an optical system with at least one non-planar mirror for folding the optical beam path. The optical system has an element with a surface which is symmetrical to a given plane, without rotational symmetry, having an increasing or decreasing meridional curvature radius along a first intersection line with the given plane and an increasing or decreasing sagital curvature radius along the same line. The latter intersection line may be defined by a quadratic equation.