Patent ID: 9134520
Filing Date: 2015-09-15
Classification: G02B

Abstract:
1. A microscope objective lens comprising, in order from an object side: a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power, wherein the first lens group includes a positive lens component having a lens surface positioned nearest to the object side and having a negative refractive power and at least one cemented lens component having a combined positive refractive power, the second lens group includes a diffractive optical element that joins two diffractive element components respectively made from different optical materials and which has a diffractive optical surface on which diffractive grating grooves are formed on a bonded surface of the two diffractive element components, and at least one cemented lens component, the third lens group includes at least one achromatic lens component having a combined negative refractive power, and a lens surface of the third lens group nearest to an image side is arranged so that a concave surface of the lens surface faces the image side, the microscope objective lens is configured such that if r denotes a curvature radius of the surface having a negative refractive power of the positive lens component provided in the first lens group, n if f denotes a focal length of the microscope objective lens and h denotes a height from an optical axis of a principal ray of a light bundle passing through the diffractive optical surface and corresponding to a maximum field angle, then the microscope objective lens satisfies a condition expressed by