| 摘要 |
A double-sided, holographic replica comprises a web of transparent, thermoplastic, sheet material having a separate series of off-axis-recorded, phase-modulated holograms pressed into each of the opposite surfaces, respectively, of the web. Oppositely disposed (front and rear) holograms are such as to provide angularly displaced reconstructed images, respectively, when a monochromatic read-out beam is transmitted through the web. The double-sided holographic replica is made by first pressing the web and a first holographic master between a first pair of heated calender rollers to form one replica on one surface of the web, and then pressing the web, while thermoplastically adhered to the first master, and a second holographic master between a second pair of heated calender rollers to form another replica on the other surface of the web. The first and second masters are subsequently cooled and separated from the web.
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