Method for providing a polarizing layer on an optical element

Abstract

A method for providing a polarizing layer on a curved optical element comprises using a support for temporarily carrying the polarizing layer. The support is resilient so that it can conform with the curved surface of the optical element. An adhesive layer is first deposited on the optical element surface, and the polarizing layer is applied on the adhesive layer by pressing the support. Then, the support is peeled so that the polarizing layer remains on the optical element. The method is compatible with high efficiency polarizing layer based on dichroic compounds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general view of a first device suitable for implementing a method according to the invention.

FIG. 2 is a cross-sectional view of an optical element used for implementing a method according to the invention.

FIG. 3 is a cross-sectional view of a carrier used for implementing a method according to the invention.

FIG. 4 is a general view of a second device suitable for implementing a method according to the invention.

Claims

1. Method for providing a polarizing layer on a curved optical element, comprising the following steps: a/ applying a polarizing layer on a surface of a resilient support, said support being in a planar shape;b/ warping the resilient support with the polarizing layer thereon;c/ bringing the polarizing layer supported by the warped support into contact with a curved surface of the optical element; andd/ removing the support from the optical element surface so that the polarizing layer is transferred from the support onto the optical element,

2. Method according to claim 1, wherein step /a/ comprises the following substeps: a1/ forming a layer of a substance comprising organic dichroic compounds on the surface of the resilient support; anda2/ applying a stress to the substance layer when the resilient support is in a planar shape, so that the dichroic compounds produce a polarizing effect of the substance layer for a light beam transmitted through said layer.

3. Method according to claim 1, wherein the polarizing layer has an order parameter S equal to or greater than 0.8 during steps /b/ to /d/, said order parameter S being calculated using the following formula:

4. Method according to claim 1, wherein the resilient support is based on a material selected from the list comprising polyethylene, polypropylene, polyethyleneterephtalate, polycarbonate, silicone and a visquene.

5. Method according to claim 1, wherein the polarizing layer is applied on the resilient support in step /a/ with a release layer arranged between said resilient support and said polarizing layer.

6. Method according to claim 5, wherein the release layer comprises an acrylic matrix and at least one silicone surfactant.

7. Method according to claim 6, wherein the release layer is formed from a precursor solution based on an acrylated siloxane polyalkyleneoxide copolymer dissolved in n-propanol.

8. Method according to claim 1, wherein the adhesive layer is deposited on the optical element surface by spin coating.

9. Method according to claim 1, wherein the adhesive layer comprises a material selected from a family comprising epoxy-type materials, pressure-sensitive adhesives and latex-type materials.

10. Method according to claim 1, wherein the polarizing layer comprises dichroic compounds, at least part of said dichroic compounds being molecules or molecule fragments with planar structures and forming a crystalline lattice in the polarizing layer.

11. Method according to claim 10, wherein the polarizing layer has a three-dimensional crystalline lattice formed by the molecules or molecule fragments of said dichroic compounds.

12. Method according to claim 10, wherein the dichroic compounds are selected from the class of azo dyes.

13. Method according to claim 10, wherein the dichroic compounds are selected from the class of polycyclic dyes.

14. Method according to claim 13, wherein the dichroic compounds are selected from the list comprising sulfonation products of indanthrone, Vat dark green G dye, VAT Scarlet 2G dye, quinacridone and dibenzoimidazole derivative of perylene tetracarboxylic acid.

15. Method according to claim 13, wherein the polarizing layer comprises a mixture of sulfonation products of indanthrone, VAT Scarlet 2G dye and dibenzoimidazole derivative of perylene tetracarboxylic acid.

16. Method according to claim 1, wherein step /a/ comprises depositing a liquid crystalline solution onto the surface of the resilient support so as to form a layer, said solution further incorporating dichroic compounds having planar structures, and step /a/ further comprises drying the solution layer.

17. Method according to claim 16, wherein step /a/ further comprises applying a stress to the solution layer, so that the dichroic compounds produce a polarizing effect of the layer for a light beam transmitted through said layer.

18. Method according to claim 17, wherein the stress is applied to the solution layer during the deposition of the liquid crystalline solution onto the support surface.

19. Method according to claim 1, further comprising a step of treating the polarizing layer with at least a solution of bi- or tri-valent metal salt, so that the polarizing layer becomes water-insoluble.

20. Method according to claim 2, wherein step /a2/ is carried out by stretching the resilient support with the substance layer thereon.

21. Method according to claim 2, wherein step /a2/ is carried out by rolling a rod on the substance layer supported by the resilient support in a planar shape, with a controlled thrust.

22. Method according to claim 1, wherein step /b/ is carried out by embossing the resilient support with a stamp on a side of said support opposite to the polarizing layer.

23. Method according to claim 22, wherein the embossing of the resilient support is carried out with a controlled pressure equal to or greater than 20 bars.

24. Method according to claim 1, wherein step /c/ is carried out with a two-step process comprising: /c1/ moving the optical element towards the polarizing layer until a point-contact is made between the adhesive layer and the polarizing layer; and/c2/ forcing the support against the optical element surface until the polarizing layer is pressed on the adhesive layer at any point of the curved surface of said optical element.

25. Method according to claim 24, wherein the optical element is moved towards the polarizing layer in step /c1/ by creating a depression in a sealed volume surrounding a residual gap between the adhesive layer and the polarizing layer.

26. Method according to claim 24, wherein the resilient support is forced against the optical element surface in step /c2/ by pushing said support with a resilient pad on a side opposite to the polarizing layer.

27. Method according to claim 26, wherein the resilient pad is part of a stamp used for warping the resilient support in step /b/.

28. Method according to claim 1, wherein steps /b/ to /d/ are carried out by using a device comprising: a vacuum vessel;a fixing ring designed to maintain fixedly a peripheral edge of the resilient support so as to seal the vacuum vessel on a closing face;an element holder located inside of the vacuum vessel;a stamping system located outside the vacuum vessel and designed for forcing a stamp against the resilient support so as to push a center part of said resilient support towards inside the vacuum vessel;a lifting system designed to move the element holder until an upper surface of the element enters into contact with the support maintained by the fixing ring, and designed to be controlled by a depression created in the vacuum vessel ; anda stop-system designed to maintain the lifting system in a fixed position once the upper surface of the element has entered into contact with the support.

29. Method according to claim 28, wherein the device further comprises a controller designed to control a thrust of the stamping system when the stamp is forced against the resilient support.

30. Method according to claim 1, wherein steps /b/ and /c/ are carried out simultaneously, so that the polarizing layer enters in contact with the adhesive layer on the curved surface of the optical element when the resilient support is made warped with the polarizing layer thereon.

31. Method according to claim 30, wherein the resilient support is made warped by forcing said support with the polarizing layer thereon against the optical element surface, by means of a fluid pressure applied to the resilient support on a side of said support opposite to the polarizing layer.

32. Method according to claim 31, wherein the fluid pressure is greater than or equal to 5 psi.

33. Method according to claim 1, wherein an additional coating is first formed on the support surface, the polarizing layer being formed on top of said additional coating in step /a/, and wherein said additional coating is transferred onto the optical element together with the polarizing layer in steps /b/ to /d/.

34. Optical element comprising: an optical base element with at least one curved surface;an adhesive layer arranged on said curved surface; anda polarizing layer retained on the optical base element by the adhesive layer,

35. Optical element according to claim 34, designed for ophthalmic use.

36. Optical element according to claim 35, comprising an eyeglass, for example designed for mounting within a frame of spectacles.

37. Optical element according to claim 34, wherein the polarizing layer has an order parameter S equal to or greater than 0.8, said order parameter S being calculated using the following formula:

38. Optical element according to claim 34, wherein the dichroic compounds are molecules or molecule fragments having planar structures, and wherein at least part of said compounds form a crystalline lattice in the polarizing layer.

39. Optical element according to claim 38, wherein the polarizing layer has a three-dimensional crystalline lattice formed by the molecules or molecule fragments of said dichroic compounds.

40. Optical element according to claim 38, wherein the dichroic compounds are selected from the class of azo dyes.

41. Optical element according to claim 38, wherein the dichroic compounds are selected from the class of polycyclic dyes.

42. Optical element according to claim 41, wherein the dichroic compounds are selected from the list comprising sulfonation products of indanthrone, Vat dark green G dye, VAT Scarlet 2G dye, quinacridone and dibenzoimidazole derivative of perylene tetracarboxylic acid.

43. Optical element according to claim 41, wherein the polarizing layer comprises a mixture of sulfonation products of indanthrone, VAT Scarlet 2G dye and dibenzoimidazole derivative of perylene tetracarboxylic acid.

44. Optical element according to claim 34, wherein the dichroic compounds are molecules or molecule fragments having planar structures, and wherein said compounds are spread within a liquid crystalline matrix of the polarizing layer, said liquid crystalline matrix being selected so as to set an angular orientation of the molecules or molecule fragments of the dichroic compounds.

45. Optical element according to claim 34, wherein the polarizing layer is water-insoluble.

46. Optical element according to claim 34, further comprising an additional coating arranged on the polarizing layer, on a side opposite to the optical base element.

47. Optical element according to claim 46, wherein the additional coating comprises an antireflective coating, a hard coating, a low-friction coating or a hydrophobic coating.