In the past two years discovered a form of x-ray white-light interferometry, and based on it a type of x-ray phase contrast imaging device capable of detecting the refractive bending of x-rays at sub-nanoradian resolution with broadband x-ray sources. We invented a way to retrieve the phase information without the need for mechanical scanning, and an adaptive image reconstruction algorithm to suit future application environments outside the ideal laboratory setting. These methods are further developed and optimized, on the path towards realizing the benefit x-ray phase-contrast imaging in clinical applications. A foundation of the above work is hard x-ray diffraction gratings of 200 nm periods. They are accomplished in another project of our laboratory in collaboration with several extramural groups.