| 摘要 |
PURPOSE:To produce an optional number of optically equivalent holograms, by controlling the quantity of exposing light so as to make the diffraction efficiency constant by paying attention to the intensity of transmitting light which is in a functional relation with the diffraction efficiency. CONSTITUTION:The intensity of the light used for exposing a storage body on the surface side of the a recording body, the intensity of the light after passing through the recording body, and the intensity of the light passing through the recording body immediately after the exposure is started are designated as A, B, and B0, respectively. Then, by paying attention to the B, B/A, A/B, B/B0, or B0/B, exposure is performed until the noticed quantity coincides with a previously set value. When the set value K is inputted to an arithmetic control circuit 38 through a keyboard 40 and a shutter 12 is successively opened by the circuit 38 before taking holograms, the exposure is started. The intensities of light B and A detected by photoreceptor elements 26 and 28 are amplified by amplifiers 30 and 32 and successively fetched by the arithmetic control circuit 38 after they are converted into digital signals by AD converters 34 and 36.
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