GB968025A - Improvements in optical mirrors - Google Patents

Abstract

968,025. Laminates. HERAEUS QUARZSCHMELZE G.m.b.H. Dec. 5, 1960 [Dec. 5, 1959; June 3, 1960], No. 41763/60. Heading B5N. [Also in Division G2] In an optical mirror comprising a reflective coating and a supporting arrangement therefor, said supporting arrangement is formed of fused silica, quartz glass, ceramics material or high melting point glass with a high SiO 2 content, all being materials having a low coefficient of expansion, and comprises a carrier plate supported by tubular supporting means, each of said supporting means having an end secured to said plate, said plate and said supporting means being formed from one of said materials. A base plate may also be provided secured to the other ends of the tubular members. The preferred material for both plates and tubular members is fused silica. The tubular members may have any suitable cross-section, for example, circular or polygonal, and may be formed with no space between them (thereby assuming a honeycomb structure) as in Figs. 4 and 5 (not shown). The tubular members may be integral with, welded to, sweated on or optically sprung on to the plate or plates. The front plate may for example be plane or concave. In the embodiment shown in Fig. 1, a carrier plate 3 for the reflective coating is supported by tubular members 2 secured at their ends respectively to the plate 3 and to a base plate 1. The plate 1 may be extended upwards to the edge of the plate 3 and may be welded thereto. Ventilation holes 4, 5 are pro. vided in the tubular members and base plate respectively. In a second embodiment (Fig. 2), the front plate is in two parts, the outer part of which is of transparent silica and the inner part of which (like the tubular members) is of translucent silica. The tubular members 2 are secured to the base plate 1 in such a way that their lower ends are open.