Patent number: 6612701

Image enhancement in a real image projection system, using on-axis reflectors, at least one of which is aspheric in shape

Original Assignee: Optical Products Development Corporation

Field of technology: Optics

Patent granted on: Tue, 02 Sep 2003

Patent drawing

Abstract

A real image projection system comprising two or more optical surfaces of revolution, with at least one comprising an aspheric surface of revolution. The aspheric surface of revolution is of a design to reduce natural aberrations inherent in imaging using surface of revolutions of the conic family of curves. In one embodiment, a real image projection system includes a pair of curved reflector segments of the conical family of curves, wherein at least one of the reflector segments has an aspherical surface of revolution, the primary segment being of longer focal length relative to the secondary segment, and an object positioned substantially at the focal point of the longer focal length reflector segment, such that a real image is positioned substantially at the focal point of the shorter focal length reflector segment, and the real image is projected along a viewing axis extending from the object positioned at the focal point of the primary reflector segment to the surface of the primary reflector segment, to the surface of the secondary reflector segment, to the focal point of the secondary reflector segment, to a viewer.