Method for manufacturing a mirror

Patent metadata

Field	Value
Publication number	US-9952403-B2
Application number	US-201514752314-A
Country	US
Kind code	B2
Filing date	Jun 26, 2015
Priority date	Jun 27, 2014
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A method for producing a mirror comprising a plurality of optical surfaces, the method comprises: a step of producing elements, step of assembling the elements with each other from the rear, a step of fixing the elements from the rear onto a supporting structure of the mirror, and a step of polishing subsequent to the step of fixing the elements in order to obtain the optical surfaces of the mirror and correct the residual positioning defects of the optical surfaces and polish them.

First claim

The invention claimed is:

1. A method for producing a mirror having a plurality of optical surfaces disposed around an opening, the method comprising:
a step of producing independently a plurality of elements, a face of each element in the plurality of elements contributing to an optical surface of said mirror;
a step of fixing the plurality of elements together by a side reverse from said face and onto a supporting structure of the mirror, said supporting structure maintaining the opening; and
a step of global polishing of said respective faces of the plurality of elements fixed together subsequent to the step of fixing the plurality of elements onto the supporting structure to obtain the optical surface of the mirror and correct residual positioning defects of the optical surface,
wherein a difference in a coefficient of thermal expansion between the elements and the supporting structure is less than a threshold value; and
wherein the threshold value is 5 μm/m/K.

2. The method as claimed in claim 1 , wherein the elements and the supporting structure comprise materials having identical thermoelastic characteristics.

3. The method as claimed in claim 1 , wherein the difference in the coefficient of thermal expansion between means for fixing the elements onto the supporting structure and said elements is less than said threshold value.

4. The method as claimed in claim 1 , wherein the elements comprise, Si3N4 (Silicon Nitride) or SiC (Silicon Carbide) or a material compatible with space optics applications.

5. The method as claimed in claim 1 , wherein said elements are of hexagonal shape, and wherein an assembly of the elements forms a polygon.

6. The method as claimed in claim 5 , wherein the opening is inside the polygon.

7. A method for producing a mirror having a plurality of optical surfaces disposed around an opening, the method comprising:
a step of producing independently a plurality of elements, a face of each element in the plurality of elements contributing to an optical surface of said mirror;
a step of fixing the plurality of elements together by a side reverse from said face and onto a supporting structure of the mirror, said supporting structure maintaining the opening; and
a step of global polishing of said respective faces of the plurality of elements fixed together subsequent to the step of fixing the plurality of elements onto the supporting structure to obtain the optical surface of the mirror and correct residual positioning defects of the optical surface,
wherein the elements and the supporting structure comprise materials having identical thermoelastic characteristics.

8. The method as claimed in claim 7 , wherein the elements comprise, Si3N4 (Silicon Nitride) or SiC (Silicon Carbide) or a material compatible with space optics applications.

9. The method as claimed in claim 7 , wherein said elements are of hexagonal shape, and wherein an assembly of the elements forms a polygon.

10. The method as claimed in claim 9 , wherein the opening is inside the polygon.

11. The method as claimed in claim 7 , wherein a difference in a coefficient of thermal expansion between the elements and the supporting structure is less than a threshold value.

12. The method as claimed in claim 11 , wherein the threshold value is 5 μm/m/K.

13. The method as claimed in claim 11 , wherein the difference in the coefficient of thermal expansion between means for fixing the elements onto the supporting structure and said elements is less than said threshold value.

14. A method for producing a mirror having a plurality of optical surfaces disposed around an opening, the method comprising:
a step of producing independently a plurality of elements, a face of each element in the plurality of elements contributing to an optical surface of said mirror;
a step of fixing the plurality of elements together by a side reverse from said face and onto a supporting structure of the mirror, said supporting structure maintaining the opening; and
a step of global polishing of said respective faces of the plurality of elements fixed together subsequent to the step of fixing the plurality of elements onto the supporting structure to obtain the optical surface of the mirror and correct residual positioning defects of the optical surface,
wherein the elements and said supporting structure comprise, Si 3 N 4 (Silicon Nitride) or SiC (Silicon Carbide) or a material compatible with space optics applications.

15. The method as claimed in claim 14 , wherein a difference in a coefficient of thermal expansion between the elements and the supporting structure is less than a threshold value.

16. The method as claimed in claim 15 , wherein the threshold value is 5 μm/m/K.

17. The method as claimed in claim 15 , wherein the difference in the coefficient of thermal expansion between means for fixing the elements onto the supporting structure and said elements is less than said threshold value.

18. The method as claimed in claim 14 , wherein the elements and the supporting structure comprise materials having identical thermoelastic characteristics.

19. The method as claimed in claim 14 , wherein said elements are of hexagonal shape, and wherein an assembly of the elements forms a polygon.

20. The method as claimed in claim 19 , wherein the opening is inside the polygon.

Assignees

• Thales Sa

Inventors

• Falzon Frédéric
• Devilliers Christophe
• Laborde Cyrille

Classifications

• G02B7/183 Primary

  specially adapted for very large mirrors, e.g. for astronomy, {or solar concentrators} · CPC title

• G02B5/09

  Multifaceted or polygonal mirrors {, e.g. polygonal scanning mirrors; Fresnel mirrors} · CPC title

• G02B23/00

  Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices · CPC title

• G02B5/10

  with curved faces · CPC title

• G02B7/181 Primary

  with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation · CPC title