Patent ID: 7936441
Filing Date: 2011-05-03
Classification: G02B,G03F

Abstract:
1. An immersion projection optical system for projecting an image of a first plane onto a second plane through a liquid, the immersion projection optical system comprising: a first optical element having a first optical surface that contacts the liquid and a second optical surface that faces the first plane, wherein the first optical element includes a held portion contactable with a holding member to hold the first optical element, the held portion being arranged on a holding plane that is orthogonal to an optical axis of the first optical element, the first optical element defining a space thereon, located between the held portion and the optical axis and extending depthwise into the first optical element from the first optical surface, the space extending sufficiently depthwise into the first optical element to cross through the holding plane; and a member including a projecting portion that extends, from outside the space, into the space through the holding plane without contacting the first optical element.