Patent ID: 7619829

Claim:
An immersion objective lens for an inverted microscope, the immersion objective lens comprising: a front lens; a lens frame which supports the front lens, the lens frame including a curved surface surrounding the front lens; and a liquid preventive frame which is attached around the lens frame, the liquid preventive frame including a liquid bulb holding wall which holds a liquid supplied onto the front lens, a distal end of the liquid bulb holding wall being located behind a distal end face of the front lens along a center axis of the front lens, and a liquid supplied channel which extends through an interior of the liquid preventive frame, the liquid supplied channel having an inner opening which is open to an inner side of the liquid bulb holding wall and an outer opening which is open to an outer side of the liquid preventive frame, wherein liquid is supplied from the inner opening through the liquid supplied channel from the outer opening which is connected to an external liquid supply device; wherein the liquid preventive frame includes a liquid receiving portion which receives the liquid that has moved from inside to outside the liquid bulb holding wall, and the liquid receiving portion includes a liquid drain channel which discharges the liquid outside the liquid preventive frame.