Patent ID: 6795255
Filing Date: 2004-09-21
Classification: G02B

Abstract:
A projection objective consisting of seven lenses bordering to space on both sides, characterized by the following conditional equations, which must be met in their entirety:u&gE;12.8Â°, 100 mm&lE;LEP&lE;400 mm, &sgr;RBa&gE;1Â°, &sgr;RBi&gE;âˆ’14Â°, wherebyu is the aperture angle (2u-entire angle) on the lighting side, LEP is the distance of the entrance pupil (on the lighting side) to object level (the location in direction of projection from reference point object level is a positive number), &sgr;RBa is the ray's angular slope opposite the optical axis in the object space between the object and the objective's 1st lens area, which limits the bundle for the field margin (object's outer field point) outwardly (away from the optical axis, distant from the axis) and &sgr;RBi is the ray's angular slope opposite the optical axis in the object space between the object and the objective's 1st lens area, which limits the bundle for the field margin (object's outer field point) inwardly (toward the optical axis, near the axis), as well as that angles &sgr;RBa and &sgr;RBi are positive, if the respective rays intersect the optical axis at a location, which, when seen from the object, is in the opposite direction to projection and negative, if intersecting the optical axis at a location, which, when seen from the object, is in direction of projection, with the following lens locations in sequence from image (enlarged side) to object (shrunk and lighting side): a first biconvex lens (1), a second negative lens (2), with concave surface at image side, a third positive lens (3), with convex surface at image side, a fourth negative lens (4), with concave surface on object side, a fifth negative lens (5), with concave surface at image side, a sixth positive lens (6), with convex surface on object side, and a seventh biconvex lens (7).