| 摘要 |
<p>A numerical-aperture limiter for an optical imaging system, comprising at least one pair of wedge-like prisms made of a transparent material of a known index of refraction, the prisms of said pair being disposed in close mutual proximity and in opposite orientation, with the narrow end of one prism adjacent to the wide end of the other prism, the prism surfaces, facing one another, of each prism of said pair of prisms being spaced apart from one another by a distance at least equal to the wavelength of the light used by said imaging system, with a vertex angle of each one of said prisms being a function of the desired numerical aperture and the index of refraction of said material. <IMAGE></p> |
