An optical beam splitter.

摘要

An optical beam splitter including a prescribed number of stacked transparent parallel plates (Pi) whose thicknesses are uniform to a high degree of precision, the back surface of the transparent parallel plate which is the farthest from the side at which light beam that is to be split enters is coated with a totally reflective film (Mo), while the back surfaces of all of the remaining transparent parallel plates are coated with different semi-reflective films (Mi) whose respective reflectivities gradually increase and the coating region of the totally reflective film and semi-reflective films are positioned in an oblique arrangement which is struck by the light beam traveling obliquely through the interiors of the transparent parallel plates. With this optical beam splitter, the incident light beam (Lo) is converted into a number of split light beams (Li) which are of equal luminous intensity by partial reflection by the respective semi-reflective films and total reflection by the totally reflective film, and the respective split light beams are emitted parallel to each other in a tow in the direction of the side of the stack from which the incident light beam initially entered without any of the split light beams striking the preceding semi-reflective films.