| 摘要 |
PROBLEM TO BE SOLVED: To realize an objective optical system whose outside diameter is small, whose entire length is long, whose chromatic aberration is satisfactorily corrected, and which is suitable for in-vivo observation with sufficiently long length and a wide observation range. SOLUTION: The compact objective optical system 1 is constituted of a 1st lens group G<SB>1</SB>having positive power, a 2nd lens group G<SB>2</SB>including a cemented lens, a 3rd lens group G<SB>3</SB>constituted of a biconvex lens, a 4th lens group G<SB>4</SB>including a cemented lens and having positive power, and a 5th lens group G<SB>5</SB>having positive power in order from an object side. Then, the bonded surface of the cemented lens included in the 2nd lens group G<SB>2</SB>and that of the cemented lens included in the 4th lens group G<SB>4</SB>both have negative power. COPYRIGHT: (C)2006,JPO&NCIPI
|
