| 摘要 |
An image bearing composite optical material is formed as a laminated flexible sheet having an image bearing photographic quality film layer variously bonded between outer and inner translucent layers of paper, fabric, or synthetic materials. The composite optical material provides two sharply distinct appearances dependent upon being viewed under backlit or ambient illumination conditions. Full-colored and precisely detailed images are produced under backlighted conditions; a plain appearance is produced otherwise. Improved embodiments include a nonbilateral structure wherein a middle image bearing film layer is bonded over its entire adjacent surface with an outer translucent layer, and is bonded at widely separated points or along thin lines with an inner translucent layer to produce an air gap there between. The air gap embodiment negates image transmission under nonbacklit viewing conditions.
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