| 摘要 |
A normally flat, rectangular mirror element is supported on the front surface of a normally flat, rectangular backing element, which is more rigid than the mirror element. A pair of spacer elements are positioned between the mirror element and the backing element to raise the mirror element above the backing element. The spacer elements are located adjacent one pair of parallel edges of the mirror element. To curve the mirror about a central longitudinal bending axis which is parallel to the spacer elements, the mirror is depressed at its center, along the longitudinal axis, and secured to the backing element by a strip of double sided adhesive tape, which maintains the mirror element in the depressed position. To impart a concave curvature to the mirror element, the mirror element and the backing element are both curved about a transverse bending axis, which is orthogonal to the longitudinal bending axis, by pulling the backing element in a direction away from the mirror element while supporting two edges of the backing element on a frame to provide resistance to the pulling. The backing element is pulled by a rod which is secured by one end to the backing element and which threads into a turnbuckle at the other end. The turnbuckle is joined to a portion of the frame by another rod which extends from the frame and which also threads into the turnbuckle. Rotation of the turnbuckle varies the degree of curvature of the backing element and the mirror element about the transverse axis. |
