Patent ID: 8885237

Claim:
A computer-generated hologram preparation method of preparing a hologram where an original image is recorded as interference fringes on a predetermined recording surface by way of arithmetic operations using a computer, the method comprising: a step of defining an original image formed as a three-dimensional image, a hologram recording plane for recording the original image and reference light to be irradiated onto the hologram recording plane; a step of defining using the computer a large number of arithmetic operation points on the hologram recording plane and arithmetically determining the intensity of the interference wave formed by an object light beam emitted from each object and the reference light for each of the arithmetic operation points; and a step of preparing physical interference fringes on a medium on the basis of the intensity distribution of interference wave obtained on the recording plane in the arithmetically determining step; the front-most part of the three-dimensional image being arranged near the hologram recording plane at the time of defining the original image, wherein an intensity value at each arithmetic operation point is expressed with gradation information.