| 摘要 |
PROBLEM TO BE SOLVED: To obtain a screen on which an image projected from a projector is clearly projected even under natural light in the open air by forming an image projection surface with aluminum or its alloy subjected to etching treatment or alumite formation treatment. SOLUTION: An aluminum or aluminum alloy sheet 21 is stuck to a substrate comprising plywood and they are fixed in a woody frame to obtain the objective screen. The surface of the sheet 21 has been subjected to etching treatment or alumite formation treatment. The surface of the aluminum AL subjected to alumite formation treatment has a porous anodic oxide film 21A having plural slender pores 21a pierced in the thickness direction. By the action of the pores 21a, an image projected from a projector is reflected with directivity.
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