| 摘要 |
<p>Objective (1) having a first partial objective (3) which projects a first field plane (7) onto an intermediate image (11) and comprises a first convex mirror (13) with a first central mirror aperture (15) and a second concave mirror (17) with a second central mirror aperture (19), the first mirror (13) having a first axial spacing from the second mirror (17 )', and the second mirror (17) having a second axial spacing from the intermediate image (11), and the ratio of the first axial spacing to the second axial spacing having a value of between 0.95 and 1.05, in particular between 0.98 and 1.02, and a second partial objective (5), which projects the intermediate image (11) onto a second field plane (9) and comprises a third concave mirror (21) with a third central mirror aperture (23) and a fourth concave mirror (25) with a fourth central mirror aperture (27) 1 the third mirror (21) having from the second field plane (9) a third axial spacing ZM3-IM which has the following relationship with a numerical aperture NA in the second field plane (9) and with a diameter DUM3 of the third mirror (21) : (I), the objective (1) having a Petzval radius whose absolute value is greater than the axial spacing of the first field plane (7) from the second field plane (9) .</p> |
