Multiple glazing with variable scattering by liquid crystals and its method of manufacture

1. A multiple glazing with variable scattering by liquid crystals comprising:

first and second flat float glass sheets sealed on the edge of their internal faces by a sealing joint;

on the internal faces of the first and second glass sheets, first and second electrodes in the form of transparent electrically conductive layers provided with a power supply;

on the first and second electrodes, a layer of liquid crystals adapted to alternate reversibly between a transparent state and a translucent state by application of an alternating electric field, which layer has an average thickness E from 15 to 60 μm and incorporates spacers,

wherein a thickness of each of the first and second glass sheets is less than or equal to 5.5 mm, and

wherein each of the internal faces coated with the first and second electrodes has a dioptric defect score, expressed in millidioptres, of less than 12E/15 where the thickness E of the liquid crystals is in μm.

2. The multiple glazing with variable scattering by liquid crystals according to claim 1 , wherein

for a thickness E of less than 30 μm, the thickness of the first glass sheet and the second glass sheet lies from 3 mm to 5.5 mm,

and

for a thickness E greater than or equal to 30 μm, the thickness of the first glass sheet and the second glass sheet lies from 2 mm to 5.5 mm.

3. The multiple glazing with variable scattering by liquid crystals according to claim 1 , wherein the sealing joint has a width and is interrupted in its width by a plurality of openings each defining lateral joint ends, and wherein for each opening an additional sealing material forms a bridge between the lateral ends of the joint, thus forming material continuity.

4. The multiple glazing with variable scattering by liquid crystals according to claim 3 , wherein the sealing joint is interrupted in its width by at least two openings facing a first edge of the glazing and by at least two other openings facing a second edge opposite the first edge.

5. The multiple glazing with variable scattering by liquid crystals according to claim 1 , wherein the sealing joint and/or an additional sealing material is essentially organic.

6. A method comprising arranging the multiple glazing with variable scattering by liquid crystals according to claim 1 as glazing in vehicles or buildings.

7. A method for producing multiple glazing with variable scattering by liquid crystals according to claim 1 , comprising:

forming the sealing joint, said forming comprising applying the sealing material on the first float glass sheet provided with the first electrode;

liquid depositing the layer of liquid crystals with an average thickness E on the first float glass sheet provided with the first electrode and optionally on the second float glass sheet provided with the second electrode;

after forming the sealing joint and depositing the layer of liquid crystals, bringing the first and second glass sheets in contact; and

before bringing the first and second glass sheets in contact, forming the plurality of said openings of the sealing joint each defining the lateral ends of the joint.

8. The method for producing multiple glazing with variable scattering by liquid crystals according to claim 7 , wherein the sealing joint is interrupted in its width by at least two openings facing a first edge of the glazing and by at least two other openings facing a second edge opposite the first edge, and wherein the assembly of the first and second glass sheets is carried out by calendering, the first and second edges corresponding to the edges in the direction of calendering.

9. The method for producing multiple glazing with variable scattering by liquid crystals according to claim 8 , wherein the assembly of the first and second glass sheets is carried out by pressing, wherein the sealing joint is interrupted in its width by at least two openings facing a third edge of the glazing adjacent to the first edge and by at least two other openings facing a fourth edge opposite the third edge.

10. The method for producing multiple glazing with variable scattering by liquid crystals according to claim 7 , comprising applying the additional sealing material, forming a bridge between the lateral ends of the joint.

11. The method for producing multiple glazing with variable scattering by liquid crystals according to claim 10 , wherein the additional sealing material consists of said sealing material, thus forming material continuity.

12. The multiple glazing with variable scattering by liquid crystals according to claim 5 , wherein the sealing joint and/or the additional sealing material is made of epoxy resin.

13. The method for producing multiple glazing with variable scattering by liquid crystals according to claim 11 , wherein the additional sealing material is made of epoxy resin.

14. A multiple glazing comprising:

first and second glass sheets each having a face sealed on an edge thereof by a sealing joint;

first and second electrodes arranged respectively on the face of the first and second glass sheets, each of the first and second electrodes including an electrically conductive layer provided with a power supply;

a layer of liquid crystals arranged on the first and second electrodes and adapted to alternate reversibly between a transparent state and a translucent state when an alternating electric field is applied, the layer having an average thickness E from 15 to 60 μm and incorporating a plurality of spacers,

wherein a thickness of each of the first and second glass sheets is less than or equal to 5.5 mm, and

wherein each of the faces coated, respectively, with the first and second electrodes has a dioptric defect score, expressed in millidioptres, of less than 12E/15 where the thickness E of the liquid crystals is in μm.