Konica Minolta Opto, Inc.

Minolta Company, Ltd.

Mitsuaki Shimo

Kenji Konno

Soh Ohzawa

Hitoshi Hagimori

Jun Ishihara

Katsuhiro Takamoto

Provided is a magnified-projection optical system, which can retain a considerably long back focus although a focal length is short and which has a small chromatic aberration. The optical system comprises a projecting optical system, a relay optical system and a display element, which are sequentially arrayed from a screen side along the optical axis. The projecting optical system enlarges and projects the image, which has been linearly focused by the relay optical system, on the screen, and includes a negative group and a positive group arrayed sequentially from the screen side and having a negative optical power and a positive optical power, respectively. The optical system satisfies the following conditional relations of |Fb/F|&#x3e;10 and 0.5&#x3c;|F/Fp|&#x3c;2.0, wherein Fb: the back focus of the whole optical system including the projecting optical system and the relay optical system, F: the focal length of the whole optical system, and FP: the focal length of the projecting optical system,

Magnified-projection optical system and digital type planetarium device

An optical system has a plurality of optical surfaces and an aperture stop, and has an eccentric reflective surface as at least one of the plurality of optical surfaces. For different conjugate distances, focusing for keeping a position of an entire image surface substantially constant while keeping substantially constant an axial imaging position and an angle of incidence of an axial principal ray on an image surface is performed by parallel and rotational movement of a group provided as a focusing group having at least one surface as the eccentric reflective surface.

Focusing method and image-taking apparatus

A taking optical system for forming an optical image of an object on the light-receiving surface of an image sensor has at least one optical prism that has an entrance surface, at least three reflective surfaces each curved, and an exit surface, and that receives rays from the object side through the entrance surface, then reflects the rays on the at least three reflective surfaces, and then lets out the rays through the exit surface. The optical prism is formed of a medium having a refractive index of 1.2 or more. An optical aperture is disposed on or near one of the at least three reflective surfaces. At least one of the at least three reflective surfaces is an eccentrically disposed rotation-asymmetric surface. Let the ray traveling from the center of the object through the center of the optical aperture to the center of the image surface be called a base ray, then the intersections of the base ray with the entrance surface, each of the reflective surfaces, and the exit surface all lie approximately on the same plane.

Taking optical system

An image-taking optical system for forming an optical image of an object on the light-receiving surface of an image sensor includes a plurality of optical blocks. The optical blocks each have a prism unit provided with a curved surface and an optical unit composed of a member different from a member composing the prism unit. The prism unit uses the curved surface as a total reflection surface and also as a transmission surface. The optical unit has near the curved surface a curved surface identically or substantially identically shaped therewith.

Image-taking optical system

A zoom lens system comprises, from the object side, a first lens unit having a positive refractive power, a second lens unit having a positive refractive power and a third lens unit having a negative refractive power. During zooming, the sizes of the first area of empty space between the first lens unit and the second lens unit and the second area of empty space between the second lens unit and the third lens unit change.

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Osaka, Japan

Mitsuaki Shimo