Optical imaging system with an extended depth-of-field and method for designing an optical imaging system

摘要

A method for designing a mask, the method includes: choosing or receiving a desired contrast value; and determining sizes, locations and shapes of multiple rotationally symmetric regions of a mask such as to define a modulation transfer function that is characterized by a substantially uniform response over a spatial frequency range; wherein the uniform response is substantially indifferent to an orientation of features of the object and to a location of the object within a deep depth-of-field region. An optical imaging system that includes: a mask that includes multiple rotationally regions; wherein the multiple rotationally symmetric regions are shaped and positioned such as to define a modulation transfer function that is characterized by a substantially uniform response over a spatial frequency range, wherein the uniform response is substantially indifferent to an orientation of features of the object and to a location of the object within a deep depth-of-field region.