| 摘要 |
1,167,891. Telescope mirrors. OWENSILLINOIS Inc. March 7, 1966 [March 5, 1965; July 1, 1965], No.9809/66. Heading G2J. [Also in Division C1] A light-weight telescope mirror blank comprises a base-plate 12 of glass or transparent glassceramic with oppositely disposed surfaces 14, 15, the surface 14 having inwardly extending cavities 13 and being fused to a back-up plate 16, the plate 16 being of the same material as the base-plate 12 and when both are of glass-ceramic; the cavities 13 have rounded corners. Glasses used may be fused silica or borosilicate glass. The preferred glass-ceramics are as disclosed in Specification 1,124,002. The base-plate 12 may be formed in a mould (10) with upstanding projections (11) or, as shown in Fig. 5, in a mould 23 by immersion of a die 26 with projections 27, the base 24 of the mould being curved if desired to give a base-plate 25 with a concave outer surface 28. The back-up plate 16 may be plain as in Fig. 2, or, as in Fig. 4, may be formed with openings 21 positioned to open into each of the cavities 13. |
