Positioning alignment apparatus and method using holographic optical elements

摘要

An apparatus and a method employ on a subject at least one holographic optical element that develops two beams of focused light whose focal configurations appear in predetermined locations which correspond to the position of the subject in the system. In a first preferred embodiment, two holographic optical elements are recorded on a subject that is to be aligned and supported by a holder assembly. During exposure of the holographic optical elements, the light rays passing through the plate converge of two focal points that have position coordinates which define their locations in the coordinate space of the optical system. Each focused point of light strikes a position sensitive detector which develops output signals that represent the position coordinates of the focused point of light in the system. After it has been removed from and returned to the holder assembly, the plate is aligned in proper position the two focused points of light strike the areas on the detectors which provide output signals that correspond to the position coordinates produced during exposure. In a second preferred embodiment, a single holographic optical element is recorded on the surface of a glass plate and develops the first and second beams of light that converge to different focal points in the optical system.