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US 9,069,155 B2Granted
Zoom lens and image pickup apparatus
AssigneeFUJIFILM Corporation
InventorDaiki Kawamura
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AssigneeFUJIFILM Corporation
InventorDaiki Kawamura
Estimating the term…
Disposing from an object side in the order of a positive first lens group which is fixed at the time of zooming, a negative second lens group which is moved at the time of zooming, an aperture stop, a positive third lens group which is fixed at the time of zooming, and a fourth lens group which is moved along the optical axis at the time of zooming to correct a change in image plane position arising from the zooming for focusing. The zoom lens is configured to simultaneously satisfy, when a focal length of the overall lens system at the telephoto end, an overall optical length, and an Abbe number of the second group first lens with respect to d-line are taken as ft, TL, and νd21 respectively, conditional expressions (1): 0.62<TL/ft<0.88 and (2): 30<νd21<48.
A zoom lens, consisting of a first lens group which has a positive power and is fixed at the time of zooming, a second lens group which has a negative power and is moved along an optical axis at the time of zooming, an aperture stop, a third lens group which has a positive power and is fixed at the time of zooming, and a fourth lens group which is moved along the optical axis at the time of zooming to correct a change in image plane position arising from the zooming for focusing, disposed in this order from an object side, wherein:
A zoom lens, consisting of a first lens group which has a positive power and is fixed at the time of zooming, a second lens group which has a negative power and is moved along an optical axis at the time of zooming, an aperture stop, a third lens group which has a positive power and is fixed at the time of zooming, and a fourth lens group which is moved along the optical axis at the time of zooming to correct a change in image plane position arising from the zooming for focusing, disposed in this order from an object side, wherein:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras: having zoom function
Having four groups only: the first group being positive
By axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of…:…
Optical elements, systems or apparatus
About 5 years 4 months of term left · ends 22 Feb 2032 (estimated)
The present invention relates to a zoom lens having four lens groups and an image pickup apparatus equipped with the zoom lens.
Heretofore, zoom lenses having four lens groups are widely known as general zoom lenses installed on image pickup devices, such as consumer video cameras, surveillance cameras, and the like. The zoom lens includes a first lens group having a positive power, a second lens group having a negative power, a third lens group having a positive power, and a fourth lens group having a positive power arranged in this order from the object side and, when zooming, while the second lens group is moved in a optical axis direction, the fourth lens group is moved to correct a change in image plane position arising from the zooming for focusing. Further, a zoom lens of five lens groups in which a fifth lens group is added as a fixed lens group is also known.
For example, as a zoom lens having a high zoom ratio, a very compact zoom lens is known as described, for example, in Japanese Unexamined Patent Publication Nos. 2007-148340 and 2009-192598.
FIG. 1 is a cross-sectional view of an image pickup apparatus equipped with a zoom lens of the present invention, illustrating a schematic configuration thereof.
FIG. 2 is a cross-sectional view of a zoom lens of Example 1, comparatively illustrating the state in which the zoom is set to a wide angle end and the state in which it is set to a telephoto end.
FIG. 3 is a cross-sectional view of a zoom lens of Example 2, comparatively illustrating the state in which the zoom is set to a wide angle end and the state in which it is set to a telephoto end.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an image pickup apparatus of the present invention equipped with a zoom lens of the present invention, illustrating a schematic configuration thereof. Note that FIG. 1 illustrates an optical path passing the optical axis and an optical path passing outside the optical axis.
FIG. 1 commonly illustrates an image pickup apparatus 300A according to a first embodiment equipped with a zoom lens 100A according to a first embodiment of the present invention, an image pickup apparatus 300B according to a second embodiment equipped with a zoom lens 100B according to a second embodiment of the present invention, and an image pickup apparatus 300C according to a third embodiment equipped with a zoom lens 100C according to a third embodiment of the present invention.
The image pickup apparatus 300A according to the first embodiment of the present invention includes the zoom lens 100A and an image sensor 200 having an imaging plane 210 on which a large number of light receiving pixels are disposed for capturing an optical image 1K of a subject 1 formed through the zoom lens 100A.