Production method of phase type computer-generated hologram

摘要

PROBLEM TO BE SOLVED: To improve shape accuracy by having plural cells to impart prescribed phases to plural portions varying in the wave fronts of light from each other and confining the phase jumps of these plural cells to π or below. ;SOLUTION: A calculator hologram 2 is formed on a substrate 1 on a lower side by specifying the number of phase sampling to N=4. The entire part of the hologram is looked over and the phase of the cell where the jump exceeding πis generated is regulated by utilizing the fact that the phase term of the light has a period 2π. If, for example, the cell 3 having the projecting jump of 3π/2 exists, -π/2 subtracting 2π from the original phase 3π/2 of the cell 3 is imparted to the cell as the fresh phase value to the cell. As a result, the required number of etching times is increased but the difference in level from the adjacent cells is suppressed to ≤π, by which the manufacture of the surface shape with the good accuracy is made possible. As a result, the surface shape of the calculator hologram 2 has no more jumps exceeding π.;COPYRIGHT: (C)2000,JPO