Pattern projector for automatic focusing endoscope

Claim 1

An endoscope system, comprising: (a) an image fiber having an object end and an observer end; (b) a light intensity detector related to the observer end of the image fiber for detecting the intensity of light emanating from the observer end of the image fiber; (c) a focusing lens adjustably related to the image fiber so that when the observer end of the image fiber is aimed at an object, the focusing lens may be adjusted to maximize an intensity of illumination at the detector as an indication that the object has been brought into focus upon the detector; (d) a pattern having at least two adjoining sharply contrasting regions; (e) means for illuminating said pattern; (f) an optical system for projecting said pattern, as illuminated by said illuminating means, upon the observer end of said image fiber for transmission through said image fiber and onto said object, whereby: even though said object may have no regions of sufficiently high contrast as to otherwise permit detection at the detector of when said object has been brought into focus at the detector, the reflection of the projection of said illuminated pattern from said object as detected at said detector provides said sufficiently high contrast; and (g) said detector being so arranged relative to the image fiber observer end that said reflection reaches said detector from said object without intermediately reaching the illuminated pattern.