OPTICAL SYSTEM AND IMAGE CAPTURING DEVICE HAVING THE SAME

• Main Author: NAKADA TAKEHARU
• Format: Patent
• Language: English; Japanese
• Published: 16.03.2022
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

To provide an optical system which is compact and well corrected for various aberrations including chromatic aberration.SOLUTION: An optical system provided comprises a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, and a rear group LR comprising one or more lens groups and having positive refractive power, which are arranged in order from the object side to the image side. When shifting focus from an object at infinity to a nearby object, the second lens group L2 moves toward the image side and distances between adjacent lens groups change. An Abbe number νdGP of a material of a positive lens GP located on the side closest to the image in the first lens group L1, a distance D1 from the lens surface on the side closest to the object in the first lens group L1 to the lens surface on the side closest to the image in the first lens group L1, a distance LD from the lens surface on the side closest to the object in the optical system to the image plane along an optical axis, and a focal length fL1 of the first lens group L1 satisfy given conditional expressions.SELECTED DRAWING: Figure 1 【課題】小型かつ色収差等の諸収差が良好に補正された光学系を提供する。【解決手段】物体側から像側へ順に配置された、正の屈折力の第１レンズ群Ｌ１、負の屈折力の第２レンズ群Ｌ２、１以上のレンズ群を含み全体で正の屈折力の後群ＬＲからなる光学系であって、無限遠物体から近距離物体へのフォーカシングに際して、第２レンズ群Ｌ２は像側へ移動し、隣接するレンズ群の間隔が変化し、第１レンズ群Ｌ１のうち最も像側に配置された正レンズＧＰの材料のアッベ数νｄＧＰ、第１レンズ群Ｌ１における最も物体側のレンズ面から第１レンズ群Ｌ１における最も像側のレンズ面までの光軸上での距離Ｄ１、光学系における最も物体側のレンズ面から像面までの光軸上での距離ＬＤ、第１レンズ群Ｌ１の焦点距離ｆＬ１は、所定の条件式を満足する。【選択図】図１