Patent Number: 
Section: claims

1. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said grating being configured as one of a phase grating, an analyzer grating, and an absorption grating. 2. The grating of claim 1, projections of said sub-gratings resulting in an effective grating with a smaller effective pitch than the pitches of said sub-gratings. 3. The grating of claim 1, said sub-gratings having the same pitch. 4. The grating of claim 3, wherein the displacement of one of said sub-gratings from another one of said sub-gratings is an offset amounting to a fraction of half the pitch. 5. The grating of claim 1, wherein the sub-gratings have an equal bars/gap ratio. 6. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein the pitch of one of said sub-gratings is a multiple of the pitch of another one of said sub-gratings. 7. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein said sub-gratings each has a height that creates a π-phase shift at a design wavelength. 8. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said sub-gratings being arranged on a single wafer. 9. A detector arrangement of an X-ray system for generating phase-contrast images of an object, said arrangement comprising:an X-ray source;a source grating;a phase grating;an analyzer grating; anda detector,wherein the X-ray source is adapted to generate polychromatic spectrum of X-rays; andwherein at least one of the phase and analyzer gratings is a grating according to claim 1. 10. An X-ray system for generating phase-contrast data of an object, said system comprising the detector arrangement of claim 9. 11. A method of phase-contrast imaging for examining an object of interest, comprising:applying X-ray radiation beams of an X-ray source to a source-grating splitting the beams;applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;applying the recombined beams to an analyzer grating; andrecording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating,wherein at least one of the phase and analyzer gratings is a grating according to claim 1. 12. A non-transitory computer-readable medium embodying a computer program for examination of an object of interest via phase-contrast imaging, said program having instructions executable by a processor of an X-ray system for causing the system to carry out a plurality of acts, among said plurality there being the acts of:applying (52) X-ray radiation beams of an X-ray source to a source-grating splitting the beams;applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;applying the recombined beams to an analyzer grating; andrecording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating;wherein at least one of the phase and analyzer gratings is a grating according to claim 1. 13. The grating of claim 1, said sub-gratings having respective front surfaces and being arranged so that said surfaces are disposed normal to said beam and face in a direction of arrival of said beam. 14. The grating of claim 1, a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating. 15. The grating of claim 2, said effective grating being defined by sidewalls in a propagation direction of an X-ray beam, in which direction said sub-gratings face. 16. The grating of claim 15, a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating. 17. The computer readable medium of claim 12, among said plurality of acts there being a further act of computing the recorded raw image data into display data. 18. The grating of claim 1, said sub-gratings facing in a same direction. 19. The grating of claim 18, the displacement being normal to said direction. 20. The grating of claim 18, the respective displacements of each of said sub-gratings from the other one or more of said sub-gratings being normal to said direction.