Claims
- 1. A method for the preparation of a base body of a reflecting mirror comprising (A) a front plate having an optically flat or curved surface made from transparent-fused quartz glass or high-silica glass, (B) a porous foamed body of fused quartz glass or high-silica glass bonded to the surface of the front plate opposite to the optically flat or curved surface, (C) a rear plate made from fused quartz glass or high-silica glass bonded to the surface of the porous foamed body opposite to the front plate and (D) a reinforcing side layer of fused quartz glass or high-silica glass bonded to the side surface of the porous foamed body, which method comprises the steps of:
- (a) sandwiching said porous foamed body of fused quartz glass or high-silica glass with two plates of fused quartz glass or high-silica glass to serve, one, as the front plate and, the other, as the rear plate with an interposed layer of a finely divided silica powder between the front plate and the porous foamed body and between the rear plate and the porous foamed body;
- (b) surrounding the porous foamed body with a hoop of fused quartz glass or high-silica glass keeping a gap between the hoop and the side surface of the porous foamed body;
- (c) filling the gap between the hoop and the side surface of the porous foamed body with a finely divided silica powder; and
- (d) heating the assemblage of the front plate, porous foamed body, rear plate and hoop with the interposed layers of a finely divided silica powder at a temperature higher than the softening point of the silica powder so as to integrate the front plate and rear plate and hoop with the porous foamed body.
Priority Claims (2)
Number |
Date |
Country |
Kind |
3-93212 |
Mar 1991 |
JPX |
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3-155593 |
May 1991 |
JPX |
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Parent Case Info
This is a divisional application Ser. No. 07/775,095 filed Oct. 11, 1991 pending.
US Referenced Citations (21)
Foreign Referenced Citations (2)
Number |
Date |
Country |
352375 |
Jul 1931 |
GBX |
0968025 |
Aug 1964 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Zito, "A Method of Making Ultralight Primary Mirrors", SPIE vol. 1494, Space Astronomical Telescopes and Instruments (1991) pp. 491-497. |
Divisions (1)
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Number |
Date |
Country |
Parent |
775095 |
Oct 1991 |
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