| 摘要 |
This invention provides an optical element that produces a high intra-pupil transmittance and a high resolution with minimal shading-performance degradation even when mounted separately from a lens unit. Said optical element has the following: a central region, centered on the optical axis, in which the relative transmittance with respect to the location of maximum transmittance is 95% or more; an intermediate region, formed around the central region, in which the transmittance decreases toward the outside; and a peripheral region, formed around the intermediate region, in which the transmittance is 0.5% or less. Letting ϕ1 represent the diameter of the central region, letting ϕ2 represent the diameter of the boundary between the intermediate region and the peripheral region, and letting ϕa represent the aperture diameter of the optical system, the central region, the intermediate region, and the peripheral region are formed so as to satisfy the relation 1.1 ≤ ϕ2/ϕa ≤ 2.1 and at least one of the relations 0.1 ≤ ϕ1/ϕa ≤ 1.1 and 0.0 ≤ ϕ1/ϕ2 ≤ 0.95. |
