Device for measuring distance of an object from the forward end portion of an endoscope

Claim 1

In a device for measuring the distance of an object from the forward end portion of an endoscope adapted to be inserted into a hollow portion of a living body or the like for the inspection thereof, said endoscope comprising a control housing, an elongated tube, said control housing being connected to said forward end portion through said elongated tube, an image transmitting optical system extending through said elongated tube and an objective provided in said forward end portion in front of the forward end of said image transmitting optical system, said image transmitting optical system transmitting an image of the oject formed on the forward end thereof by said objective lens system the rearward end in said control housing thereby permitting the thus transmitted image to be viewed through ocular means provided in said control housing wherein the improvement comprises, light projecting means for emitting a pair of light beams toward the object from said forward end portion of the endoscope at positions each a certain distance spaced from said objective lens system so as to form two light spots on the surface of the object inspected through the endoscope, thereby permitting the distance of the object from the forward end portion of the endoscope to be determined on the basis of the relative positions of the light spots in the field of view, said light projecting means being comprised of a fiber optical system extending from said control housing through said elongated tube to said forward end portion with the other end thereof adjacent to said control housing being supplied with light from an external light source, light being transmitted through said fiber optical system to the forward end thereof, a collimating lens system located in front of the forward end of said fiber optical system, a semi-transparent light reflecting mirror, and a total light reflecting mirror located in the optical axis of said collimating lens system, said total light reflecting mirror being spaced a certain distance from said semi-transparent lighT reflecting means, said two light reflecting mirrors being positioned opposite to each other with respect to said objective lens system, thereby permitting the reflected light beam to be directed toward the object within the field of view.