Curved lenses and related methods

• US 9,759,850 B2
• Filed: 04/16/2012
• Issued: 09/12/2017
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: Safilo SpA (Safilo Group SPA)
• Original Assignee: Safilo SpA (Safilo Group SPA)
• Inventors: Boinard, Eric, Boinard, Pascal
• Primary Examiner(s): Gupta, Yogendra
• Assistant Examiner(s): Le, Ninh
• Application Number:
  US13/447,353
• Publication Number:
  US 20120262666A1
• Time in Patent Office: 1,975 Days
• CPC Class Codes: B29C 33/405 Elastomers, e.g. rubber B29C33/50 takes precedence
• CPC Class Codes: B29C 33/42 characterised by the shape of the moulding surface, e.g. ribs or grooves
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 43/203 Making multilayered articles
• CPC Class Codes: B29C 51/428 of moulds or mould parts
• CPC Class Codes: B29D 11/00413 made by moulding between two mould parts which are not in direct contact with one another, e.g. comprising a seal between or on the edges B29D11/00019 - B29D11/00355, B29D11/00423, B29D11/00432 take precedence
• CPC Class Codes: B29D 11/00644 polarizing
• CPC Class Codes: B29D 11/0073 Optical laminates
• CPC Class Codes: B29K 2007/00 Use of natural rubber as moulding material
• CPC Class Codes: B29K 2009/00 Use of rubber derived from conjugated dienes, as moulding material
• CPC Class Codes: B29K 2019/00 Use of rubber not provided for in a single one of main groups B29K2007/00 - B29K2011/00, as moulding material
• CPC Class Codes: B29K 2021/003 Thermoplastic elastomers
• CPC Class Codes: B29K 2021/006 Thermosetting elastomers
• CPC Class Codes: B29K 2995/0034 Polarising
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02C 7/12 Polarisers

Abstract

Curved lenses and methods for making curved lenses are described. One embodiment of a method of making a curved lens includes curving a lens blank made of a linear polarizer layer laminated together with a plurality of polymeric layers. The lens blank is curved by heating and pressing the lens blank between a curved rigid member and a flexible member at a pressure and maintaining the pressure for a time sufficient to allow the lens blank to conform to the shape of the curved rigid member. Methods of the invention may be used to make curved lenses with different polarization properties and curvatures.

Claims

1. A method of making a formed lens, the method comprising:

obtaining a lens blank comprising, in superposed relation, a linear polarizer layer laminated together with a plurality of polymeric layers, the linear polarizer layer having a polarization axis;

placing a lens blank on a flat flexible member of elastomer, the flat flexible member contacting an entirety of, and supporting, the lens blank, wherein the lens blank and the flat flexible member are each initially and essentially planar, and wherein the flat flexible member of elastomer has;

a thickness between about 0.5 mm and about 5.0 mm;

a shore hardness A between about 25 and about 70;

a tensile strength between about 5 MPa and about 30 MPa;

an elongation at break between about 100% and about 1000%; and

a resistance to tearing between about 50 N/cm to about 1000 N/cm;

heating and applying a pressure to the lens blank by pressing the lens blank between a curved rigid member and the flat flexible member, causing the flat flexible member to assume a shape of the curved rigid member while supporting the lens blank therebetween; and

maintaining the pressure for a time sufficient to allow the lens blank to conform to the shape of the curved rigid member and the flat flexible member.

2. The method of claim 1, wherein heating is conducted at about 70°

C. to about 200°

C.

3. The method of claim 1, wherein the pressure is about 1.5 MPa to about 15 MPa.

4. The method of claim 1, further comprising cooling the lens blank while maintaining the pressure.

5. The method of claim 4, wherein cooling is conducted at about 20°

C. to about 90°

C.

6. The method of claim 1, further comprising, preheating the lens blank to a temperature of about 20°

C. to about 150°

C. prior to applying the pressure.

7. The method of claim 1, wherein at least one of the polymeric layers is an optical wave retarder having a fast axis and the fast axis is aligned at an angle relative to the polarizer axis.

8. The method of claim 7, wherein the angle renders the lens a linear polarizer.

9. The method of claim 7, wherein the angle renders the lens an elliptical polarizer.

10. The method of claim 7, wherein the angle renders the lens a circular polarizer.

11. The method of claim 10, further comprising coating a concave surface and a convex surface of the formed lens with an anti-reflective coating.

12. The method of claim 11, wherein the formed lens has a parallel polarizer transmittance equal to or greater than 90% and a cross polarizer transmittance equal to or less than 0.5%.

13. The method of claim 1, wherein the shape of the curved rigid member produces a spherically shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature and second radius of curvature are equal.

14. The method of claim 1, wherein the shape of the curved rigid member produces a toroidally shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature and second radius curvature are not equal.

15. The method of claim 1, wherein the shape of the curved rigid member produces a cylindrically shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature is non-zero and the second radius of curvature is zero.

16. A method of making a formed lens, the method comprising:

obtaining a flexible lens blank comprising, in superposed relation, a linear polarizer layer laminated together with a plurality of polymeric layers, the linear polarizer layer having a polarization axis;

placing the flexible lens blank on a flexible member of elastomer, the flexible member contacting an entirety of, and supporting, the flexible lens blank, wherein the flexible lens blank and the flexible member are each initially and essentially planar, and wherein the flexible member of elastomer has;

a thickness between about 0.5 mm and about 5.0 mm;

a shore hardness A between about 25 and about 70;

a tensile strength between about 5 MPa and about 30 MPa;

an elongation at break between about 100% and about 1000%; and

a resistance to tearing between about 50 N/cm to about 1000 N/cm;

heating the flexible lens blank to a forming temperature by pressing the flexible lens blank at a pressure between a curved rigid member and the flexible member, while the flexible member supports the flexible lens blank, the curved rigid member being at the forming temperature;

maintaining the pressure while heating at the forming temperature for allowing the flexible lens blank to assume a shape of the curved rigid member;

reducing the temperature to a reduced temperature while maintaining the pressure for allowing the flexible lens blank to maintain a convex side and a concave side once the pressure is removed; and

removing the flexible lens blank from between the curved rigid member and the flexible member.

17. The method of claim 16, wherein the forming temperature is about 70°

C. to about 200°

C.

18. The method of claim 16, wherein the pressure is about 1.5 MPa to about 15 MPa.

19. The method of claim 16, wherein the reduced temperature is about 20°

C. to about 90°

C.

20. The method of claim 16, further comprising, preheating the lens blank to a temperature of about 20°

C. to about 150°

C. prior to applying the pressure.

21. The method of claim 16, wherein at least one of the polymeric layers is an optical wave retarder having a fast axis and the fast axis is aligned at an angle relative to the polarizer axis.

22. The method of claim 21, wherein the angle renders the lens a liner polarizer.

23. The method of claim 21, wherein the angle renders the lens an elliptical polarizer.

24. The method of claim 21, wherein the angle renders the lens a circular polarizer.

25. The method of claim 24, further comprising coating a concave surface and a convex surface of the formed lens with an anti-reflective coating.

26. The method of claim 25, wherein the formed lens has a parallel polarizer transmittance equal to or greater than 90% and a cross polarizer transmittance equal to or less than 0.5%.

27. The method of claim 16, wherein the shape of the curved rigid member produces a spherically shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature and second radius curvature are equal.

28. The method of claim 16, wherein the shape of the curved rigid member and flexible member produce a toroidally shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature and second radius of curvature are not equal.

29. The method of claim 16, wherein the shape of the curved rigid member and flexible member produced a cylindrically shaped lens having a first radius of curvature and a second radius of curvature perpendicular to the first radius of curvature, wherein the first radius of curvature is non-zero and the second radius of curvature is zero.

30. A method of making eyewear, the method comprising:

obtaining a first lens and a second lens, the first lens and the second lens comprising, in superposed relation, a linear polarizer layer laminated together with a plurality of polymeric layers, the linear polarizer layer having a polarization axis, the first lens and the second lens being formed from lens blanks into a desired shape according to the following steps;

placing a lens blank on a flexible member of elastomer, the flexible member contacting an entirety of, and supporting, the lens blank, wherein the lens blank and the flexible member are each initially and essentially planar; and

wherein the flexible member of elastomer has;

a thickness between about 0.5 mm and about 5.0 mm;

a shore hardness A between about 25 and about 70;

a tensile strength between about 5 MPa and about 30 MPa;

an elongation at break between about 100% and about 1000%; and

a resistance to tearing between about 50 N/cm to about 1000 N/cm;

heating and applying a pressure to the lens blank separately by pressing the lens blanks between a curved rigid member and the flexible member, while the flexible member supports the lens blank, causing the flexible member to assume a shape of the curved rigid member;

maintaining the pressure for a time sufficient to allow the lens blank to conform to the shape of the curved rigid member and the flexible member, the curved rigid member responsible for a force to form a concave side of the lens blank and the flexible member responsible for a responsive force to form a convex side of the lens blank; and

placing the first lens and the second lens into an eyeglass frame.