| 摘要 |
A mirror-typically of the spherical or aspherical variety-is replicated on a large scale (in the order of 2'x4') to an optical accuracy in the range of less than one arc minute. An optical master is created by heat shrinking and holding an acrylic sheet to a steel substrate of the same shape as desired mirror in the constant presence of a vacuum at the steel-acrylic interface. The acrylic is optically polished to complete the master. The master is then appropriately dammed to the mirror dimension and poured with subsequently cured epoxy so that the epoxy forms the optical surface of the replicated mirror. A backing master-created by substantially the same process as the optical master-allows fabrication of a backing, composed of a series of adhesive layers typically sandwiching a core material such as commercial honeycomb therebetween, to be made with a curvature substantially similar to the curvature of the replicated optical surface. This backing is laid up against and dammed around the replicated epoxy optical surface with an interstice of pre-selected dimension created between the replicated epoxy surface and backing. An adhesion is produced between the backing and replicated surface by pouring a curing adhesive rubber into the defined interstice, this adhesion occurring substantially without any backing irregularity "print through" to the optical surface. Thereafter, a peeling release of the optical master from the adhered replicated optical surface and backing is effected by flexing (as by shrinking of the acrylic dome through cold nitrogen gas). A lightweight replicated mirror of substantial strength separated from reusable optical master results.
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