ZOOM LENS, IMAGING OPTICAL DEVICE, AND DIGITAL INSTRUMENT

• Main Authors: TANAKA HIROAKI, TERADA MAMORU, NOGUCHI KAZUYOSHI, TANAHASHI DAISUKE
• Format: Patent
• Language: English; Japanese
• Published: 23.03.2015
• Subjects: ACCESSORIES THEREFOR; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES; APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To provide a zoom lens capable of obtaining excellent optical performance in an entire zooming area while being reduced in size and having high manufacturability, even if the zoom lens has an angle of view at the telephoto end that is below 15°, an imaging optical device including the zoom lens, and a digital instrument including the imaging optical device.SOLUTION: In a zoom lens ZL composed of four groups in which positive, negative, positive, and negative powers are disposed in this order from an object side, when zooming power varies from a wide angle end W to a telephoto end T, a first group Gr1 moves closer to the object side, a second group Gr2 moves closer to an image side, a third group Gr3 moves closer to the object side, and a fourth group Gr4 moves closer to the object side. The zoom lens satisfies the following conditional expression:-0.63<f2/f1<-0.25,-10<f2/y'max<-3,6<f1/y'max<20 (f1: a focal distance of the first group Gr1, f2: a focal distance of the second group Gr2, y'max: a maximum image hight). 【課題】望遠端の画角が１５?を下回るようなズームレンズにおいても小型化しつつ、高い製造性を有しながらもズーム全域において良好な光学性能が得られるズームレンズ、それを備えた撮像光学装置及びデジタル機器を提供する。【解決手段】物体側から順に正負正負の４群からなるズームレンズＺＬは、広角端Ｗから望遠端Ｔへの変倍において、第１群Ｇｒ１が物体側へ移動し、第２群Ｇｒ２が像側へ移動し、第３群Ｇｒ３が物体側へ移動し、第４群Ｇｒ４が物体側へ移動し、条件式：−０．６３＜ｆ２／ｆ１＜−０．２５，−１０＜ｆ２／ｙ'ｍａｘ＜−３，６＜ｆ１／ｙ'ｍａｘ＜２０（ｆ１：第１群Ｇｒ１の焦点距離、ｆ２：第２群Ｇｒ２の焦点距離、ｙ'ｍａｘ：最大像高）を満足する。【選択図】図１