Abstract: The present invention provides a projection optical system including a first concave reflecting surface, a first convex reflecting surface, a second concave reflecting surface, and a third concave reflecting surface, wherein the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, and the third concave reflecting surface are arranged such that light from an object plane forms an image on an image plane by being reflected by the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, the first convex reflecting surface, and the third concave reflecting surface in an order named.

Abstract: The present invention provides a projection optical system including a first concave reflecting surface, a first convex reflecting surface, a second concave reflecting surface, and a third concave reflecting surface, wherein the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, and the third concave reflecting surface are arranged such that light from an object plane forms an image on an image plane by being reflected by the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, the first convex reflecting surface, and the third concave reflecting surface in an order named.

Abstract: The present invention provides a projection optical system including a first concave reflecting surface, a first convex reflecting surface, a second concave reflecting surface, and a third concave reflecting surface, wherein the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, and the third concave reflecting surface are arranged such that light from an object plane forms an image on an image plane by being reflected by the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, the first convex reflecting surface, and the third concave reflecting surface in an order named.

Abstract: The present invention provides a projection optical system including a first concave reflecting surface, a first convex reflecting surface, a second concave reflecting surface, and a third concave reflecting surface, wherein the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, and the third concave reflecting surface are arranged such that light from an object plane forms an image on an image plane by being reflected by the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, the first convex reflecting surface, and the third concave reflecting surface in an order named.

Abstract: An exposure apparatus projects a pattern of an original onto a substrate by a projection optical system to expose the substrate, wherein the projection optical system includes a mirror assembly, and the mirror assembly includes a first mirror member which has a first reflecting surface and is configured to bend an optical axis of the projection optical system, a second mirror member which has a second reflecting surface and is configured to bend the optical axis, a supporting mechanism configured to support the first mirror member and the second mirror member, and the supporting mechanism is positioned to position the first mirror member and the second mirror member while a positional relationship between the first mirror member and the second mirror member is maintained.

Abstract: An exposure apparatus projects a pattern of an original onto a substrate by a projection optical system to expose the substrate, wherein the projection optical system includes a mirror assembly, and the mirror assembly includes a first mirror member which has a first reflecting surface and is configured to bend an optical axis of the projection optical system, a second mirror member which has a second reflecting surface and is configured to bend the optical axis, a supporting mechanism configured to support the first mirror member and the second mirror member, and the supporting mechanism is positioned to position the first mirror member and the second mirror member while a positional relationship between the first mirror member and the second mirror member is maintained.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power arranged to move during variation of magnification, a third lens unit of negative refractive power arranged to compensate for shift of an image plane due to the variation of magnification, and a fourth lens unit of positive refractive power. The fourth lens unit has a focal-length changeover subunit arranged to be insertable onto and detachable from an optical axis of the zoom lens and provided for changing the focal length of the zoom lens, and an image-stabilizing lens subunit different from the focal-length changeover subunit. The image-stabilizing lens subunit is movable in such a way as to have a component perpendicular to the optical axis so as to displace an image.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power for variation of magnification, a third lens unit for compensating for shift of an image plane caused by the variation of magnification, and a fixed fourth lens unit of positive refractive power, wherein the first lens unit comprises a first lens subunit of negative refractive power fixed during focusing, a second lens subunit having a focusing function, and a third lens subunit of positive refractive power fixed during focusing, and at least one of the first lens subunit and the second lens subunit and the third lens subunit respectively have aspheric lenses.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power for variation of magnification, a third lens unit for compensating for shift of an image plane caused by the variation of magnification, and a fixed fourth lens unit of positive refractive power, wherein the first lens unit comprises a first lens subunit of negative refractive power fixed during focusing, a second lens subunit having a focusing function, and a third lens subunit of positive refractive power fixed during focusing, and at least one of the first lens subunit and the second lens subunit and the third lens subunit respectively have aspheric lenses.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power arranged to move during variation of magnification, a third lens unit of negative refractive power arranged to compensate for shift of an image plane due to the variation of magnification, and a fourth lens unit of positive refractive power. The fourth lens unit has a focal-length changeover subunit arranged to be insertable onto and detachable from an optical axis of the zoom lens and provided for changing the focal length of the zoom lens, and an image-stabilizing lens subunit different from the focal-length changeover subunit. The image-stabilizing lens subunit is movable in such a way as to have a component perpendicular to the optical axis so as to displace an image.

Abstract: A zoom lens is disclosed comprising, from front to rear a first lens unit of positive refractive power, a second lens unit of negative refractive power for varying the focal length, a third lens unit for compensating for the image shift with zooming, and a fourth lens unit having the image forming function and stationary during zooming, wherein the first lens unit is divided into two or three lens subunits, one of which is moved to effect focusing, and various rules of design are set forth to suppress well the variation of aberrations with focusing.

Abstract: A zoom lens comprises, in order from an object side to an image side, a first lens unit of positive refractive power which is stationary during zooming, a second lens unit of negative refractive power which is axially movable during zooming, a third lens unit which is axially movable during zooming, and a fourth lens unit of positive refractive power which is stationary during zooming, wherein the first lens unit comprises a front lens sub-unit including at least one positive lens and having a negative refractive power as a whole, an intermediate lens sub-unit including at least one positive lens and a cemented lens and having a positive refractive power as a whole, and a rear lens sub-unit including a cemented lens and having a positive refractive power as a whole, and wherein the intermediate lens sub-unit is moved toward the image side to effect focusing from an infinitely distant object to an object at a minimum object distance.

Abstract: A zoom lens is disclosed comprising, from front to rear a first lens unit of positive refractive power, a second lens unit of negative refractive power for varying the focal length, a third lens unit for compensating for the image shift with zooming, and a fourth lens unit having the image forming function and stationary during zooming, wherein the first lens unit is divided into two or three lens subunits, one of which is moved to effect focusing, and various rules of design are set forth to suppress well the variation of aberrations with focusing.

Abstract: A zoom lens comprising, from front to rear, a focusing lens group, a variator lens group, a compensator lens group and a relay lens group, the relay lens group consisting of a front part and a rear part with a longest air spacing therebetween, and the rear part including a first movable lens component arranged upon setting of macro photography made to move along an optical axis, and a second movable lens component arranged upon setting of tracking adjustment made to move along the optical axis.

Abstract: A zoom lens is disclosed comprising a front lens unit, an intermediate lens unit having two lens sub-units with their axial separation varying for zooming purposes, and a rear lens unit, wherein at the wide-angle end, focusing is performed by moving at least the rear lens unit, and, at the telephoto end, focusing is performed by moving the intermediate lens unit and the rear lens unit, whereby the amount of focusing movement of the intermediate lens unit from an infinitely distant object to an object at a certain short distance is greater at the telephoto end than at the wide-angled end.

Abstract: A zoom lens capable of changing the range of variable focal length to another limit, comprising, from front to rear, a zoom section including a variator and a compensator arranged upon zooming movement to vary the focal length in a predetermined range, a diaphragm, and a relay lens section receptive of the afocal light beam from the zoom section to form an image and having a front lens unit and a rear lens unit, the front lens unit being provided with a fixed sub-unit and an interchangeable sub-unit in this order from the front, wherein the interchangeable sub-unit is removed to create a space between the fixed sub-unit and the rear lens unit, into which a range changing lens unit is then inserted, so that the range of variable focal length is changed.

Abstract: In a television camera having a color resolving prism system for forming monochromatic images on the image pickup surfaces of a plurality of image pickup devices by an objective lens the color resolving prism system has first, second, third and fourth prisms as is named in the order from a side of the objective lens along the optic axis of the objective lens, the first and second prisms, with their refracting angles opening in opposite directions, are edisposed with an air layer interposed therebetween or are joined together with a dichroic layer interposed therebetween, the second and third prisms are disposed with an air layer interposed therebetween, the third and fourth prisms are joined together with a second dichroic layer interposed therebetween, and the values of the refracting angles of the first .theta..sub.10 or .theta..sub.21), second .theta..sub.10 +.theta..sub.11 or .theta..sub.22, third .theta..sub.23 and fourth .theta..sub.