A segmented chromatic phase plate comprising: - a main axis, and - at least three stacks (2 to 5) of optical flats (6, 7, 13), - the at least three stacks (2 to 5) being arranged around the main axis, characterized in that - each stack (2 to 5) comprising at least two plane-parallel optical flats (6, 7) made of different materials (11, 12), - each of the at least three stacks (2 to 5) being stacked along the main axis, and - each of the at least three stacks (2 to 5) having a same overall height along the main axis, - wherein the materials (11, 12, 14) and the thicknesses of the optical flats (6, 7, 13) in the at least three stacks (2 to 5) being selected such that optical path lengths of light of a first wavelength passing through the different ones of the at least three stacks (2 to 5) along the main axis differ by integer multiples of the first wavelength, whereas optical path lengths of light of a second wavelength passing through the different ones of the at least three stacks (2 to 5) along the main axis differ by integer multiples plus defined fractions of the second wavelength; wherein - the two materials (11, 12) of the at least two optical flats (6, 7) in all of the at least three stacks (2 to 5) have different refractive indices (n0(λ), n1(λ)) for both the first and second wavelengths; and - that- the derivatives with respect to wavelength of the differences between the optical path lengths of the different stacks are zero at at least one of the first and second wavelengths. - a main axis, and - at least three stacks (2 to 5) of optical flats (6, 7, 13), - the at least three stacks (2 to 5) being arranged around the main axis, characterized in that - each stack (2 to 5) comprising at least two plane-parallel optical flats (6, 7) made of different materials (11, 12), - each of the at least three stacks (2 to 5) being stacked along the main axis, and - each of the at least three stacks (2 to 5) having a same overall height along the main axis, - each stack (2 to 5) comprising at least two plane-parallel optical flats (6, 7) made of different materials (11, 12), - each of the at least three stacks (2 to 5) being stacked along the main axis, and - each of the at least three stacks (2 to 5) having a same overall height along the main axis, - wherein the materials (11, 12, 14) and the thicknesses of the optical flats (6, 7, 13) in the at least three stacks (2 to 5) being selected such that optical path lengths of light of a first wavelength passing through the different ones of the at least three stacks (2 to 5) along the main axis differ by integer multiples of the first wavelength, whereas optical path lengths of light of a second wavelength passing through the different ones of the at least three stacks (2 to 5) along the main axis differ by integer multiples plus defined fractions of the second wavelength; wherein - the two materials (11, 12) of the at least two optical flats (6, 7) in all of the at least three stacks (2 to 5) have different refractive indices (n0(λ), n1(λ)) for both the first and second wavelengths; and - that- the derivatives with respect to wavelength of the differences between the optical path lengths of the different stacks are zero at at least one of the first and second wavelengths. - the two materials (11, 12) of the at least two optical flats (6, 7) in all of the at least three stacks (2 to 5) have different refractive indices (n0(λ), n1(λ)) for both the first and second wavelengths; and - that- the derivatives with respect to wavelength of the differences between the optical path lengths of the different stacks are zero at at least one of the first and second wavelengths.