Device for automatic exposure control in a surgical microscope or the like

Claim 1

A self-contained unit-handling automatic-diaphragm connecting-piece assembly for selective interposition between a surgical microscope equipment and a continuously viewing camera, said assembly comprising a housing having separate means at each of two spaced openings for separable connection to such an equipment and to a selected camera body, one of said openings being on a first axis of equipment-attachment and the other of said openings being on a second axis of camera-body attachment, image-forming means mounted in said housing on said first axis, optical means including a beam-splitter mounted in said housing and so oriented with respect to said image-forming means that light entering said housing via said image-forming means is divided in part to said second axis and is further divided along a third axis, photoelectric-detector means carried by said housing and positioned for response to light directed along said third axis, amplifier means connected for response to the output of said detector means, a motor connected to drive in response to the output of said amplifier means, and a variable diaphragm carried by said housing on said first axis and coupled to said motor for varying the setting thereof, whereby exposure at an attached camera body is automatically regulated independent of camera bodY and for a span of field brightness as presented by an optical equipment attached at said one opening.