摘要 |
In order to change the number of light points and light intensities and to move positions of the light points in a real-time manner, an extremely large capacity of a memory is required. In a method according to the present invention, a memory (6) has previously stored therein data indicating a complex amplitude distribution of rays of incident light (L) on a hologram plate (4) and complex amplitude distributions on the hologram plate (4) in a case where the rays are beamed at respective points at which the rays can be beamed. The controller (5) calculates the complex amplitude distribution to be generated on the hologram plate (4) in order to generate a hologram pattern by respectively multiplying, by values indicating degrees of amplitudes of respective rays, complex amplitude distributions of rays of incident light (L) and m light points P1 through Pm to be displayed, and by calculating a sum of the values obtained by the multiplication through performing addition. The controller (5) controls the hologram plate (4) so as to configure a diffraction grating pattern corresponding to the calculated complex amplitude distribution.
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