Device for blocking optical elements

1. Device for blocking optical elements ( 14 ), including a rigid base ( 2 ) and a deformable pocket ( 3 ) attached to the rigid base ( 2 ), characterized in that the deformable pocket ( 3 ) contains a granular material ( 13 ) and in that it includes evacuation means ( 4 ) adapted to provide for the exchange of gas between the interior and the exterior of the deformable pocket ( 3 ) and sealing means ( 12 ) adapted to assure sealed contact between the deformable pocket ( 3 ) and an optical element ( 14 ) when the latter is in place against the deformable pocket ( 3 ).

2. Blocking device according to claim 1 , characterized in that the deformable pocket ( 3 ) is fixed and sealed to the rigid base ( 2 ).

3. Blocking device according to claim 1 , characterized in that the evacuation means includes a rigid finger ( 4 ) projecting from the rigid base ( 2 ) and an external section of which projects out of the deformable pocket ( 3 ).

4. Blocking device according to claim 3 , characterized in that the rigid base ( 2 ) is circular with a central axis (C) and in that the external section of the rigid finger ( 4 ) extends along this central axis (C).

5. Blocking device according to claim 3 , characterized in that the rigid finger ( 4 , 4 ′) includes a passage ( 6 , 6 ′) opening at one end outside the deformable pocket ( 3 ) and at the other end inside the deformable pocket ( 3 ) in such a manner as to provide for the exchange of gas.

6. Blocking device according to claim 3 , characterized in that the external section of the rigid finger ( 4 ″) is porous to provide for the exchange of gas.

7. Blocking device according to claim 3 , characterized in that the external section of the rigid finger ( 4 ) includes a bearing surface ( 5 ) for an optical element ( 14 ).

8. Blocking device according to claim 1 , characterized in that the sealing means includes an O-ring ( 12 ).

9. Blocking device according to claim 1 , characterized in that the sealing means ( 12 ) is fixed to the deformable pocket ( 3 ).

10. Blocking device according to claim 1 , characterized in that the sealing means ( 12 ) is formed by a protrusion on the deformable pocket ( 3 ).

11. Blocking device according to claim 1 , characterized in that the deformable pocket ( 3 ) includes spacer elements ( 15 ) on its external surface adapted to maintain a distance between the deformable pocket ( 3 ) and an optical element ( 14 ) when the latter is in place against the deformable pocket ( 3 ).

12. Blocking device according to claim 11 , characterized in that the spacer elements ( 15 ) comprise pins.

13. Blocking device according to claim 11 , characterized in that the spacer elements ( 15 ) comprise a spiral rib.

14. Blocking device according to claim 1 , characterized in that the granular material ( 13 ) is an incompressible material.

15. Blocking device according to claim 1 , characterized in that the granular material ( 13 ) comprises grains of irregular shape.

16. Blocking device according to claim 1 , characterized in that the granular material ( 13 ) comprises grains having facets.

17. Blocking device according to claim 1 , characterized in that the granular material ( 13 ) comprises grains of glass.

18. Blocking device according to claim 1 , characterized in that the granular material ( 13 ) comprises grains of sand.

19. Blocking device according to claim 1 , characterized in that it further includes:

an enclosure ( 16 ) adapted to receive the rigid base ( 2 ), the deformable pocket ( 3 ), and an optical element ( 14 ); and

means ( 25 ) for reducing the pressure inside the enclosure ( 16 ).

20. Blocking device according to claim 19 , characterized in that it further includes means ( 19 ) for retaining the rigid base ( 2 ) inside the enclosure ( 16 ).

21. Blocking device according to claim 20 , characterized in that said retaining means ( 19 ) are mounted on a spring ( 22 ).

22. Blocking device according to claim 21 , characterized in that said retaining means include a receptacle ( 19 ) mounted on a slideway ( 20 ), said spring ( 22 ) urging the receptacle ( 19 ) in the direction of the slideway ( 20 ).

23. Blocking device according to claim 20 , characterized in that the enclosure ( 16 ) includes a cover ( 17 ) provided with means for urging an optical element ( 14 ) against the deformable pocket ( 3 ) when the rigid base ( 2 ) is in place in said retaining means ( 19 ).

24. Blocking device according to claim 19 , characterized in that the enclosure ( 16 ) includes a cover ( 17 ) including retaining means ( 24 ) for an optical element ( 14 ).

25. Method of blocking an optical element, characterized in that it includes the following steps:

selecting a blocking device according to claim 19 ;

disposing the rigid base ( 2 ), the deformable pocket ( 3 ), and the lens ( 14 ) inside an enclosure ( 16 ) having an original pressure;

reducing the pressure inside the enclosure ( 16 );

returning the interior of the enclosure ( 16 ) to the original pressure;

recovering the rigid base ( 2 ), the deformable pocket ( 3 ), and the lens ( 14 ) fastened together.

26. Blocking method according to claim 25 , characterized in that it further includes, before the step of reducing the pressure inside the enclosure ( 16 ), the step of pressing one of the faces of the optical element ( 14 ) against the deformable pocket ( 3 ) so that the latter at least partially espouses the shape of the optical element ( 14 ).