Reflective fourier ptychography imaging of large surfaces

A method of operating a reflective-mode Fourier ptychographic microscope (RFPM), the method comprising:

• loading a non-biological part to be inspected onto a fixture;
• and
• selecting a program to run and control one or more predetermined aspects of the RFPM, the predetermined aspects being selectable from aspects including a spatial pattern of a multiple-component light source, a temporal pattern of the multiple-component light source, a range of defect sizes to be detected, an area of the part to be inspected, at least one height characteristic for one or more detected defects, and a number of images of the non-biological part to record, the spatial patterns and the temporal patterns to be generated by selecting individual ones of the multiple-component light source to be activated to illuminate the part at a range of predefined angles-of-incidence, the temporal patterns and the spatial patterns of further being computationally combined to increase a resolution of the detected defects over a Rayleigh limit-of-resolution for a given numerical aperture and wavelength of light;
• and
• obtaining phase-derivative measurements by differential-phase contrast (DPC) techniques from the radiation collected by the sensor element.

A method of operating a reflective-mode Fourier ptychographic microscope (RFPM) to detect defects on a surface of a part, the method comprising:

• generating, by using a programmable controller, at least one predetermined lighting pattern from a multiple-component light source configured to direct radiation on the surface, the multiple-component light source having a plurality of individual-light sources, each of the plurality of individual-light sources is configured to be activated individually, the at least one predetermined lighting pattern being selected from temporal patterns and spatial patterns, the temporal patterns and the spatial patterns to be generated by selecting individual ones of the multiple-component light source to be activated to illuminate the part at a range of predefined angles-of-incidence, the temporal patterns and the spatial patterns of the predetermined lighting pattern further being computationally combined to increase a resolution of the detected defects over a Rayleigh limit-of-resolution for a given numerical aperture and wavelength of light;
• using both brightfield-imaging and darkfield-imaging to sample a Fourier space of an image of the surface;
• collecting radiation redirected from the surface in a sensor;
• obtaining phase-derivative measurements by differential-phase contrast (DPC) techniques in an area proximate the defect from the redirected radiation collected by the sensor;
• determining an angle between an imaging axis from the surface to the sensor;
• and
• determining at least a height characteristic of one or more defects on the surface.