Claims
- 1. A base body of a reflecting mirror which is an integral body comprising:
- (A) a front plate having an optically flat or curved surface made from transparent fused quartz glass or high-silica glass; and
- (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, wherein the porous foamed body has a bulk density in the range from 0.1 to 1.1 g/cm.sup.3, and at least 30% by volume of the porosity of the porous foamed body consists of closed cells,
- wherein the porous foamed body is bonded to the front plate with a layer of a melt of a finely divided silica powder.
- 2. The base body of a reflecting mirror as claimed in claim 1 in which the front plate has a thickness in the range from 2 to 20% of the total thickness of the front plate and the porous foamed body.
- 3. The base body of claim 1, wherein the porous foamed body and front plate are bonded with the layer of silica powder by heating an assembly thereof at 1400.degree. to 1600.degree. C. at about 1 to about 4 hours.
- 4. The base body of claim 1, wherein at least 60% of the porosity of the porous foamed body is provided by closed cells.
- 5. The base body of claim 1, further comprising a rear plate of fused quartz glass or high-silica glass bonded to the surface of the porous foamed body opposite to the front plate.
- 6. The base body of claim 5, further comprising a reinforcing layer surrounding and bonded to the side of the porous foamed body.
- 7. A base body of a reflecting mirror which is an integral body comprising:
- (A) a front plate having an optically flat or curved surface made from transparent fused quartz glass or high-silica glass; and
- (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, wherein the porous foamed body has a bulk density in the range from 0.1 to 1.1 g/cm.sup.3, and at least 30% by volume of the porosity of the porous foamed body consists of closed cells having a diameter of 0.01 mm to 3 mm,
- wherein the porous foamed body is bonded to the front plate with a layer of a melt of a finely divided silica powder.
- 8. The base body of claim 7, wherein the porous foamed body and front plate are bonded with the layer of silica powder by heating an assembly thereof at 1400.degree. to 1600.degree. C. at about 1 to about 4 hours.
- 9. The base body of claim 7, wherein at least 60% of the porosity of the porous foamed body is provided by closed cells.
- 10. The base body of claim 7, further comprising a rear plate of fused quartz glass or high-silica glass bonded to the surface of the porous foamed body opposite to the front plate.
- 11. The base body of claim 10, further comprising a reinforcing layer surrounding and bonded to the side of the porous foamed body.
- 12. The base body of a reflecting mirror as claimed in claim 7 in which the front plate has a thickness in the range from 2 to 20% of the total thickness of the front plate and the porous foamed body.
Priority Claims (2)
Number |
Date |
Country |
Kind |
3-93212 |
Mar 1991 |
JPX |
|
3-155593 |
May 1991 |
JPX |
|
Parent Case Info
This is a divisional application of Ser. No. 07/775,095 filed Oct. 11, 1991.
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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