Invention Grant
- Patent Title: Wide angle lens and imaging device
- Patent Title (中): 广角镜头和成像装置
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Application No.: US13257446Application Date: 2010-03-24
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Publication No.: US08643958B2Publication Date: 2014-02-04
- Inventor: Issei Abe , Hayato Yoshida , Naoki Moniwa
- Applicant: Issei Abe , Hayato Yoshida , Naoki Moniwa
- Applicant Address: JP Tokyo
- Assignee: Ricoh Company, Ltd.
- Current Assignee: Ricoh Company, Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Oblon, Spivak, McClelland, Maier & Neustadt, L.L.P.
- Priority: JP2009-106706 20090424
- International Application: PCT/JP2010/055782 WO 20100324
- International Announcement: WO2010/122882 WO 20101028
- Main IPC: G02B9/64
- IPC: G02B9/64 ; G02B13/18

Abstract:
A wide angle lens whose field angle exceeds 160 degrees, includes a front group, an aperture stop, and a rear group arranged in this order from an object-side toward an image-side. The front group includes a first lens (negative meniscus) whose convex surface faces the object, a second lens (negative), a third lens (negative), and a fourth lens (positive), arranged in this order from the object-side toward the image-side. The rear group includes a fifth lens (positive), a sixth lens (negative), and a seventh lens (positive), arranged in this order from an aperture-side toward the image-side. The fifth and sixth lenses are combined, forming a cemented lens having positive refractive power. The fifth and sixth lenses are made of materials having Abbe numbers of greater than or equal to 50 and less than or equal to 30, respectively. A surface of the seventh lens facing the image is aspheric.
Public/Granted literature
- US20120056978A1 WIDE ANGLE LENS AND IMAGING DEVICE Public/Granted day:2012-03-08
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