Machine and method for obtaining a curved surface for a film structure

Patent metadata

Field	Value
Publication number	US-12290998-B2
Application number	US-202118016088-A
Country	US
Kind code	B2
Filing date	Jul 13, 2021
Priority date	Jul 16, 2020
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

A machine and method for obtaining a curved surface of a film structure that comprises a carrier layer and a functional film ( 212 ). The machine comprises an annular support member having a supporting face adapted for supporting the film structure, and an opening ( 10 ) that is covered by the film structure when said film structure is supported by the annular support member; a clamping system configured to clamp the annular support member and the film structure when supported by the annular support member; and a forming system configured to apply pressure, and preferably temperature, on the film structure so as to curve said film structure in or through the opening ( 10 ) of the annular support member. The opening ( 10 ) of the annular support member has a contour that is non-circular so that the obtained curvature of the functional film ( 212 ) corresponds to a target curvature.

First claim

The invention claimed is:

1. A machine for obtaining a curved surface of a film structure that comprises a carrier layer and a functional film, the machine comprising:
an annular support member having a supporting face adapted for supporting the film structure and an opening that is adapted to be covered by the film structure;
a clamping system configured to clamp the annular support member and the film structure when supported by the annular support member;
a forming system configured to, when said film structure is supported by the annular support member and clamped with said annular support member, apply gaseous pressure on the film structure so as to curve said film structure in or through the opening of the annular support member such that the gaseous pressure that is applied on the film structure imparts a curved surface to the film structure;

wherein said opening of the annular support member has a contour that is non-circular.

2. The machine according to claim 1 , wherein the machine is configured for obtaining the curved surface of the film structure that is sensibly spheric, or pseudo-spherical.

3. The machine according to claim 1 , wherein the machine has no mechanical mold or counter-mold against which the film structure may come into contact during activation of the forming system.

4. The machine according to claim 1 , wherein said non-circular contour has a first defining axis and a second defining axis, along which the opening is shorter than along the first defining axis.

5. The machine according to claim 1 , wherein the non-circular contour of the opening of said annular support member has a shape that is defined as a function of a shape of a contour of the functional film of the film structure.

6. The machine according to claim 1 , wherein the non-circular contour of the opening of said annular support member has a rounded corner rectangular shape or an oval shape.

7. The machine according to claim 1 , wherein the functional film is centered in the opening and has two axes including a minor axis corresponding to a minor axis—of the opening and a major axis corresponding to a major axis of the opening, and a film opening ratio, noted R, having a value that ranges from [0.7-1.5], R being defined as:
R=Ps *( Rs−Ps )/[ PL *( RL−PL )],
with
P S is a length of the functional film along the minor axis of the opening,
R S is a length of the opening along the minor axis of the opening,
P L is a length of the functional film along the major axis of the opening, and
R L is a length of the opening along the major axis of the opening.

8. The machine according to claim 7 , wherein the film-opening ratio R has a value included in the range [0.8-1.05].

9. The machine according to claim 1 , wherein the functional film comprises geometrical features, wherein the geometrical features further comprise:
0.7 K<XdX<1.15 K for each point of a contour of the functional film, with dX being a spacing between the functional film and the opening along an axis normal to the contour of said functional film on said point;
X being the length of the functional film along said axis normal to said point of the contour of the functional film concerned by dX; and
K being a constant.

10. The machine according to claim 1 , wherein the supporting face—of the annular support member has a grip portion adapted to receive a seal, said grip portion extending around the opening and having an inner contour that is circular.

11. The machine according to claim 10 , wherein a distance between the contour of the opening of said annular support member and the inner contour of the grip portion—is at least equal to 2 millimeters.

12. The machine according to claim 1 , wherein the clamping system comprises a clamping member configured to apply a pressure force onto the annular support member and the film structure when supported by the annular support member, so as to define a chamber between said clamping member and said film structure.

13. The machine according to claim 1 , wherein the forming system is configured to apply temperature on the film structure.

14. A method for obtaining a curved surface of an optical film structure that comprises a carrier layer and a functional film, wherein the method comprises:
providing an annular support member, with an opening that has a contour that is non-circular;
positioning the optical film structure on a supporting face of the annular support member so as to cover the opening of said annular support member by the optical film structure;
clamping the optical film structure between said annular support member and a clamping member; and
forming the optical film structure by applying a gaseous pressure on the optical film structure to curve said optical film structure through the opening of the annular support member such that the gaseous pressure that is applied on the optical film structure imparts a curved surface to the optical film structure.

15. The method according to claim 14 , wherein the functional film—has a flexibility that differs from the flexibility of the carrier layer.

16. The method according to claim 14 , wherein a size of the functional film is smaller than a size of the opening.

17. The method according to claim 14 , wherein the film structure further comprises a counter-force liner, said functional film being in between said carrier layer and said counter-force liner, the counter-force liner being fastened, directly or indirectly, to the carrier layer at least on a portion of a zone outside the functional film on at least two opposite sides of the functional film, and wherein after forming the functional film, the counter-force liner is detached from the functional film and from the carrier layer.

18. The method according to claim 14 , wherein, after forming the functional film, the functional film is further laminated on a surface of an optical article.

19. The method according to claim 18 , wherein, after the forming step and before the laminating step, a largest radius of curvature of the functional film is smaller than a smallest radius of curvature of the receiving surface of the optical article.

Assignees

• Essilor Int
• Shamir Optical Ind Ltd

Inventors

• Katzman Youval

Classifications

• B29D11/00788

  Producing optical films · CPC title

• B29C51/08

  Deep drawing or matched-mould forming, i.e. using mechanical means only · CPC title

• B29C51/12

  of articles having inserts or reinforcements · CPC title

• B29L2009/001

  the layers being loose · CPC title

• B29L2009/005

  coated · CPC title