Immersion objective lens, retention mechanism for immersion medium, and manufacturing method thereof

A method of manufacturing a retention mechanism for an immersion medium, for use in a device which observes/measures a sample by use of an immersion objective lens,

• the immersion objective lens being formed of a tip portion, a lens ring portion and a lens outer frame, the lens ring portion being formed of an entire surface inclined from the lens of the tip portion to the lens outer frame,
• the method comprising:
• forming an opening portion to be engaged around the immersion objective lens, on a bottom plate;
• arranging a wall plate along a periphery of the bottom plate;
• providing an immersion medium supply unit which supplies the immersion medium to the tip portion of the immersion objective lens:
• providing a drip draining unit of the immersion medium which drains a drip of the immersion medium from the tip portion of the immersion objective lens, on the bottom plate in vicinity of the wall plate;
• and
• arranging a first ring-member formed of a first material for retaining the immersion medium, on the bottom plate, so as to surround the opening portion,
• the bottom plate being inclined to make a side of the opening portion higher than a side of the wall plate,
• an affinity of the first ring-member with the immersion medium being lower than an affinity of an inner member of the first ring-member with the immersion medium.