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Masaru Sakamoto, Utsunomiya-Shi JP

Masaru Sakamoto, Utsunomiya-Shi JP

Patent application numberDescriptionPublished
20090034091ZOOM LENS AND IMAGE PICKUP APPARATUS HAVING THE SAME - A zoom lens comprises a first lens unit that does not move for zooming and that has a positive refractive power, a second lens unit that is configure to move to an image side during zooming from a wide angle end to a telephoto end and that has a negative refractive power, a third lens unit that is configured to reduce image plane variation due to zooming, and a fourth lens unit that does not move for zooming. The fourth lens unit comprises a fourth-F unit, a fourth-B02-05-2009
20090290229ZOOM LENS SYSTEM AND CAMERA INCLUDING THE SAME - A zoom lens system includes, in order from the object side to the image side, four lens units having positive, negative, negative and positive refractive powers. A first lens unit includes, in order from the object side to the image side: a front subunit having a negative refractive power; a middle subunit that has a positive refractive power and moves during focusing; and a rear subunit having a positive refractive power. The zoom lens system further includes a variable apex angle prism disposed on the image side of the front subunit. An average Abbe number of materials of a negative lens element and a positive lens element included in the front subunit is set appropriately so as to suppress occurrence of decentering aberration accompanying a variation of a prism apex angle.11-26-2009
20090290230ZOOM LENS SYSTEM AND CAMERA INCLUDING THE SAME - A zoom lens system includes four lens units each having positive, negative, negative and positive refractive powers in the stated order from an object side to an image side. A first lens unit includes a variable apex angle prism on the image side of at least one lens element. In this zoom lens system, a focal length of the first lens unit and imaging magnifications of a second lens unit and a fourth lens unit are set appropriately so as to suppress occurrence of decentering aberration accompanying a variation of a prism apex angle.11-26-2009
20100194969ZOOM LENS SYSTEM AND IMAGE PICKUP APPARATUS INCLUDING THE SAME - A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.08-05-2010
20110037880ZOOM LENS AND IMAGE PICKUP APPARATUS EQUIPPED WITH SAME - A zoom lens comprises first and fourth units which don't move for zooming, and second and third units moved during zooming. The first unit includes a front side partial unit which don't move for focusing, a movable partial unit moved for focusing, and a rear side partial unit which don't move for focusing, the rear side partial unit includes positive lenses and one or more negative lenses, and the following conditions are satisfied: −1.2×10−3<(θpa−θn)/(νpa−νn), and νn<30, where νn is the smallest Abbe number of the material of the negative lenses, θn is the partial dispersion ratio of the material of the negative lens of the smallest Abbe number, νpa is the average of the Abbe numbers ν of the materials of positive lenses, and θpa is the average of the partial dispersion ratio θ of the materials of the positive lenses.02-17-2011
20110080651ZOOM LENS AND IMAGE PICKUP APPARATUS INCLUDING THE SAME - A zoom lens includes, in order from an object side, a positive first lens unit without moving for zooming, a negative second lens unit for magnification, a positive third lens unit for magnification, a negative fourth lens unit compensating for image plane variation due to magnification, and a positive fifth lens unit without moving for zooming. When assuming a focal length of the entire system at a wide angle end as fW, and a zoom ratio as Z, a focal length fM at an intermediate zoom position is expressed by the equation: fM=fW×√Z. When assuming an interval between the second and third lens units at the wide angle end as L04-07-2011
20110080652ZOOM LENS AND IMAGE PICKUP APPARATUS INCLUDING SAME - A zoom lens includes, in order from an object side to an image side and arranged along an optical axis, first to fifth lens units having positive, negative, positive, positive or negative, and positive refractive power, respectively. When zooming, the second lens unit moves monotonically to the image side, the third lens unit moves to the object side in a convex locus, the fifth lens unit moves nonlinearly, and the first and fourth lens units do not move. The fourth lens unit includes a first sub lens unit and a second sub lens unit; the first sub lens unit is an image-stabilizing lens unit that includes a first lens having negative refractive power and a second lens having positive or negative refractive power. The focal length of the fourth lens unit, the focal length of the entire system at the wide-angle end, the Abbe numbers of the materials of the first and second lenses are set appropriately based on predetermined conditions.04-07-2011
20120224269ZOOM LENS AND IMAGE PICKUP APPARATUS INCLUDING THE SAME - A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, which does not move for zooming, a second lens unit having a negative refractive power, which moves during zooming, a third lens unit having a negative refractive power, which moves during zooming, an aperture stop, and a fourth lens unit having a positive refractive power, which does not move for zooming. The fourth lens unit includes a first lens sub-unit, a focal length conversion optical system configured to be inserted into or removed from an optical path, and a second lens sub-unit. A focal length of the second lens sub-unit, a distance from the aperture stop to a lens surface at the most object side of the second lens sub-unit, and an F-number of the entire zoom lens at a wide-angle end are appropriately set.09-06-2012
20120224270ZOOM LENS AND IMAGE PICKUP APPARATUS HAVING THE SAME - A zoom lens includes, in order from object side, a positive first lens unit which does not move for varying magnification, a negative second lens unit which moves for varying magnification, a negative third lens unit which moves for varying magnification, and a positive fourth lens unit which does not move for varying magnification, wherein the first lens unit includes a positive lens which satisfies the following conditions: 70<νp<85; 2.3109-06-2012

Patent applications by Masaru Sakamoto, Utsunomiya-Shi JP