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

An optical imaging system comprising:

• a mask that comprises multiple rotationally symmetrical regions;
• wherein the multiple rotationally symmetrical 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 substantially 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;
• wherein the modulation transfer function changes by up to 5% within a normalized frequency range that ranges between 0.3 and 1.3 for a defocus parameter of zero, wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.

An optical imaging system comprising:

• a mask that comprises multiple rotationally symmetrical regions;
• wherein the multiple rotationally symmetrical 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 substantially 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;
• wherein the modulation transfer function changes by up to 5% within a normalized frequency range that ranges between 0.4 and 1.5 for a defocus parameter of 2, wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.

An optical imaging system comprising:

• a mask that comprises multiple rotationally symmetrical regions;
• wherein the multiple rotationally symmetrical 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 substantially 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;
• wherein the modulation transfer function changes by up to 5% within a normalized frequency range that ranges between 0.6 and 1.6 for a defocus parameter of eight, wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.

A mask, comprising multiple rotationally symmetric 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 regardless of an orientation of features in an object space;
• wherein the modulation transfer function is above 5% over a normalized frequency range that ranges between zero and at least 1.3 for defocus parameter values that range between zero and 8;
• wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.

A mask, comprising multiple rotationally symmetric 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 regardless of an orientation of features in an object space;
• wherein the modulation transfer function changes by up to 5% within a normalized frequency range that ranges between 0.3 and 1.3 for a defocus parameter of zero, wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.

A mask, comprising multiple rotationally symmetric 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 regardless of an orientation of features in an object space;
• wherein the modulation transfer function changes by up to 5% within a normalized frequency range that ranges between 0.4 and 1.5 for a defocus parameter of 2, wherein a normalized frequency equals a spatial frequency divided by a diffraction limit of a perfectly aligned optical imaging system.