Patent ID: 8587313

Claim:
A gradient magnetic field coil device comprising: a first forward coil having a spiral shape; a second forward coil, having a spiral shape, facing the first forward spiral coil through a center region; a first reverse coil, having a spiral shape, disposed on a side of the first forward coil of the center region; and a second reverse coil, having a spiral shape, facing the first forward spiral coil through the center region, wherein a current flows through the second forward spiral coil in a same direction as a current flowing through the first forward spiral coil, and currents flow through the first and second reverse spiral coils in an opposite direction to the current flowing through the first forward coil to generate a gradient magnetic field in the center region, wherein, when the gradient magnetic field is generated, a low magnetic field region and a high magnetic field region are generated where a magnetic field crossing at least one of the first and second forward coils and first and second reverse coils has different intensities between the low and high magnetic field regions and the intensity in the high magnetic field region is higher than the intensity in the low magnetic field region, and a line width of a coil line of at least one of the first forward coil, second forward coil, first reverse coil and second reverse coil in the high magnetic field is narrower than a line width of the coil line in the low magnetic field region, and wherein the line width of the coil lines in the low magnetic field region is wider than the gap between adjacent parts of the coil line in the low magnetic field region.