Olympus Optical Company, Ltd.

Olympus Corporation

Ai Midorikawa

Tamotsu Koiwai

Takaaki Ue

For a camera lens barrel with helicoid threads, at the portion where the helicoid female thread of a fixed frame is threaded with the helicoid male thread of a rotary frame, six separation preventing pins are implanted in the portion of the helicoid male thread around the same circumference at the equal intervals. These separation presenting pins are implanted between convex thread portions of the helicoid male thread, respectively. Protruding portions of the separation preventing pins fit in and slidingly contact concave thread portions of the helicoid female thread that is threaded with the helicoid male thread in which the separation preventing pins are disposed. A contacting edge fits in and comes into sliding contact with the concave thread portion of the helicoid female thread by narrowing the circumferential surface thereof. An edge is formed around the shaft portion of each separation preventing pin, which is implanted in the rotary frame, at a position near to the end thereof by narrowing the circumferential surface of the shaft portion.

Lens barrel

An external helicoid thread is provided which includes a helicoid thread having a first ridge whose both flanks are formed at a first flank angle, and a helicoid thread having a second ridge whose both flanks are formed at a second flank angle which is different from the first flank angle. An internal helicoid thread is kept in screwed-state engagement with the external helicoid threads. And in a lens barrel obtained using a connection based on such internal and external helicoid threads, the connection provided by these helicoid threads can remain secured even if a sudden outside force is applied to the lens barrel.

There is disclosed an optical apparatus in which a lens holding frame is assembled on a frame member so that the lens holding frame can move along a plane substantially vertical to the optical axis of first and second lenses, a pair of gaps is formed between the outer periphery of the lens holding frame and the inner periphery of the frame member via the optical axis in the X- and Y-axis directions, adjustment members are selectively inserted in the gaps, and the position of the lens holding frame to the frame member in the plane substantially vertical to the optical axis is set.

Optical apparatus including lens

A lens barrel includes a zoom frame for holding a first-group frame and a second-group frame. Three follower pins are implanted in the second-group frame, and each of the follower pins includes a flange portion and a thrust abutment portion. The flange portions are interposed between the outer periphery of the second-group frame and the inner periphery of the zoom frame, so that decentering of the optical axis of the second-group frame is adjusted by the difference of the thicknesses of the flange portions. The thrust abutment portions abut on the rear end surface of insertion grooves of the zoom frame, so that inclination of the optical axis of the second-group frame is adjusted by the difference of the outside diameters of the thrust abutment portions. The position and the inclination of the optical axis of lenses can be easily adjusted by selecting and mounting the follower pins.

Lens barrel and method of assembling the same

In a lens barrel, a cam groove has a pair of wall surfaces. One of the wall surfaces, which is located on the side thereof where a rotary frame is extended by a cam follower coming into sliding contact with the wall surface, is formed at a small inclining angle. The other of the wall surfaces is formed at a large inclining angle. The cam follower has a shaft mounting portion implanted in a fixed frame and has an edge formed around the circumference surface of the shaft mounting portion at the end thereof. The surface of the cam follower, which is engaged and comes into sliding contact with the cam groove, is composed of a base end side taper surface and an extreme end side taper surface. The base end side taper surface is formed on the shaft mounting portion side, has a small inclining angle, and comes into sliding contact with one of the wall surfaces. The extreme end side taper surface has a large inclining angle and comes into sliding contact with the other of the wall surfaces. With this arrangement, in the lens barrel in which lens frames are coupled with each other by a cam mechanism arranged as described above, the cam mechanism can firmly couples the lens frames even if unintentional external force is applied to the lens barrel. This arrangement has wide versatility and does not make it difficult to mold the cam groove.

Growing community of inventors

Saitama, Japan

Ai Midorikawa