WIDE-ANGLE LENS SYSTEM

• Main Author: SHIODA RYO
• Format: Patent
• Language: English; Japanese
• Published: 29.11.2018
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

PROBLEM TO BE SOLVED: To provide a wide-angle lens system which offers good correction for aberrations, including distortion aberration, by using a plurality of aspherical surfaces and a lens material having a relatively high refractive index, and which features superior manufacturability.SOLUTION: A wide-angle lens system consists of, in order from the object side, a first lens group G1 having negative refractive power, and a succeeding lens group GR comprising one or more lens groups and having positive refractive power as a while, and is configured such that an air gap distance between the first lens group G1 and the succeeding lens group GR changes while zooming or focusing. The first lens group G1 includes a lens having a first aspherical surface, a lens having a second aspherical surface and lying on the image side relative to the lens having the first aspherical surface, a lens having negative refractive power and lying on the object side relative to the second aspherical surface, and a lens having positive refractive power. The wide-angle lens system satisfies predetermined conditional expressions.SELECTED DRAWING: Figure 1 【課題】複数の非球面と比較的高屈折率のレンズ材料を利用することで、歪曲収差を含め諸収差が良好に補正されながら、製造性に優れた広角レンズ系を提供する。【解決手段】物体側より順に、負の屈折力を有する第１レンズ群Ｇ１、１以上のレンズ群を含み、全体として正の屈折力を有する後続レンズ群ＧＲより構成され、変倍又は合焦に際して前記第１レンズ群Ｇ１と前記後続レンズ群ＧＲの空気間隔が変化し、前記第１レンズ群Ｇ１は、第１非球面を有するレンズと、前記第１非球面を有するレンズより像面側に配置される第２非球面を有するレンズを有し、前記第１レンズ群Ｇ１は、前記第２非球面より物体側に、負の屈折力を有するレンズを有し、前記第１レンズ群Ｇ１は、正の屈折力を有するレンズを有し、所定の条件式を満足することを特徴とする広角レンズ系とした。【選択図】図１