High-strength laminated sheet for optical applications

• US 20040197575A1
• Filed: 04/04/2003
• Published: 10/07/2004
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Lapp, Joseph C., Chen, David, Coppola, Frank T., Rhoads, Randy L., Tammaro, David A., Gillberg, Gunilla E., Bocko, Peter L., Edwards, Victoria A., Cook, Glen B., Vaddi, Butchi R.
• Granted Patent: US 7,514,149 B2
• Time in Patent Office: Days
• US Class Current: 428/432
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: C03B 17/02 Forming molten glass coated with coloured layers; Forming molten glass of different compositions or layers; Forming molten glass comprising reinforcements or inserts
• CPC Class Codes: C03B 17/061 by lateral drawing or extrusion
• CPC Class Codes: C03B 17/062 combined with flowing onto a solid or gaseous support from which the sheet is drawn
• CPC Class Codes: C03B 17/064 by the overflow downdraw fusion process; Isopipes therefor
• CPC Class Codes: C03B 19/12 by liquid-phase reaction processes
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A laminated sheet includes a surface layer having an optical surface that is of fire-polished quality and a core layer having a higher modulus than the surface layer to increase an overall stiffness or fracture toughness of the laminated sheet.

Claims

1. A laminated sheet, comprising:

a surface layer having an optical surface of fire-polished quality; and

a core layer having a higher modulus than the surface layer to increase an overall stiffness of the laminated sheet.

2. The laminated sheet of claim 1, wherein the optical surface is a fusion-formed surface.

3. The laminated sheet of claim 1 having a cross-draw dimension of greater than about 4 feet.

4. The laminated sheet of claim 1, wherein the core layer is separable from the surface layer.

5. The laminated sheet of claim 1, wherein a thickness of the surface layer is less than about 1 mm.

6. The laminated sheet of claim 1, wherein the surface layer and the core layer are each made of a viscoelastic material.

7. The laminated sheet of claim 6, wherein the viscoelastic material is selected from the group consisting of glasses and polymers.

8. The laminated sheet of claim 1, wherein the surface layer comprises a glass.

9. The laminated sheet of claim 8, wherein the core layer comprises a glass-ceramic.

10. The laminated sheet of claim 9, wherein the core layer is buried within the surface layer.

11. The laminated sheet of claim 1, wherein the core layer is made of a material having a low thermal shrinkage.

12. The laminated sheet of claim 1, wherein the optical surface is coated with a coating material.

13. The laminated sheet of claim 12, wherein the coating material acts as a barrier to the environment.

14. The laminated sheet of claim 12, wherein the coating material enhances selected optical properties of the surface layer.

15. The laminated sheet of claim 12, wherein the coating material comprises a conductive material.

16. The laminated sheet of claim 12, wherein the coating material comprises a semiconductive material.

17. The laminated sheet of claim 1, wherein the core layer is optically enhanced.

18. A laminated sheet, comprising:

a compressive surface layer having an optical surface that is of fire-polished quality; and

a core layer;

wherein the thermal expansion coefficients of the surface and core layers are adjusted to control stress and enhance fracture toughness of the laminated sheet.

19. The laminated sheet of claim 18, wherein the optical surface is a fusion-formed surface.

20. The laminated sheet of claim 18 having a cross-draw dimension of greater than about 4 feet.

21. The laminated sheet of claim 18, wherein a thickness of the surface layer is less than about 1 mm.

22. The laminated sheet of claim 18, wherein the surface layer and the core layer are each made of a viscoelastic material.

23. The laminated sheet of claim 22, wherein the viscoelastic material is selected from the group consisting of glasses and polymers.

24. The laminated sheet of claim 18, wherein the surface layer comprises a glass.

25. The laminated sheet of claim 24, wherein the core layer comprises a glass-ceramic.

26. A laminated sheet, comprising:

a surface layer having an optical surface that is of fire-polished quality;

a core layer having a higher modulus than the surface layer to increase an overall stiffness of the laminated sheet; and

a sacrificial layer interposed between the surface layer and the core layer.

27. The laminated sheet of claim 26, wherein the optical surface is a fusion-formed surface.

28. The laminated sheet of claim 26, wherein the surface, core, and sacrificial layers are each made of a viscoelastic material.

29. The laminated sheet of claim 28, wherein the viscoelastic material is selected from a group consisting of glasses and polymers.

30. The laminated sheet of claim 26, wherein the surface layer comprises a glass, and the core layer comprises a glass-ceramic.

31. The laminated sheet of claim 26, wherein a thickness of the surface layer is less than about 1 mm.

32. The laminated sheet of claim 26, wherein the optical surface is coated with a coating material.

33. The laminated sheet of claim 32, wherein the coating material acts as a barrier to the environment.

34. The laminated sheet of claim 32, wherein the coating material enhances selected optical properties of the surface layer.

35. The laminated sheet of claim 32, wherein the coating material comprises a conductive material.

36. The laminated sheet of claim 32, wherein the coating material comprises a semiconductive material.

37. The laminated sheet of claim 26, wherein the core layer is optically enhanced.

38. The laminated sheet of claim 26, wherein the sacrificial layer is more soluble in a selected solvent than at least the surface layer.

39. A laminated sheet, comprising:

a core layer;

a surface layer disposed on a first side of the core layer, the surface layer having an optical surface that is of fire-polished quality; and

a bottom layer disposed on a second side of the core layer;

wherein the core layer has a higher section modulus than the surface layer and the bottom layer to increase an overall stiffness of the laminated sheet.

40. The laminated sheet of claim 39, wherein the optical surface is a fusion-formed surface.

41. The laminated sheet of claim 39, wherein a thickness of the surface layer and the bottom layer is about 1 mm or less.

42. The laminated sheet of claim 39, wherein the surface and bottom layers are each made of a viscoelastic material.

43. The laminated sheet of claim 42, wherein the viscoelastic material is selected from the group consisting of glasses and polymers.

44. The laminated sheet of claim 39, wherein the core layer is made of a viscoelastic material having a low thermal shrinkage.

45. The laminated sheet of claim 39, wherein the core layer is made of an annealed glass.

46. The laminated sheet of claim 39, wherein the core layer is made of an expandable material.

47. The laminated sheet of claim 39, wherein the core layer comprises a glass-ceramic.

48. The laminated sheet of claim 39, wherein the bottom layer has a fusion-formed optical surface of fire-polished quality.

49. A method of making a laminated sheet, comprising:

supplying a first viscous, flowable material into an overflow channel;

overflowing the first viscous, flowable material in a controlled manner to form a first sheet-like flow having at least one untouched surface of fire-polished quality;

depositing at least a second material on a surface of the first sheet-like flow to form a laminated flow; and

drawing the laminated flow into a laminated sheet.

50. The method of claim 49, wherein depositing the second material comprises supplying the second material in viscous, flowable form into an overflow channel and allowing the second material to overflow in a controlled manner to form a second sheet-like flow which is merged with the first sheet-like flow. to form the laminated flow.

51. The method of claim 49, wherein depositing the second material comprises spraying the second material on the first sheet-like flow.

52. The method of claim 51, wherein the second material comprises a curable material.

53. The method of claim 52, further comprising curing the curable material while drawing the laminated flow into a laminated sheet.

54. The method of claim 49, wherein the first viscous, flowable material comprises one selected from the group consisting of polymers and glasses.

55. The method of claim 54, wherein the second viscous, flowable material comprises one selected from the group consisting of polymers and glasses.

56. A method of making a laminated sheet, comprising:

supplying a viscous, flowable material into an overflow channel;

positioning a consumable material in a flow path of the viscous, flowable material so as to introduce a compositional variation to a specific portion of the viscous, flowable material;

overflowing the viscous, flowable material in a controlled manner to form a sheet-like flow having at least one untouched surface of fire-polished quality; and

drawing the sheet-like flow into a laminated sheet.

57. The method of claim 56, wherein the consumable material comprises a nucleating agent for a glass-ceramic.

58. A method of making a laminated sheet, comprising:

forming a first sheet-like flow by a continuous sol-gel process;

supplying a viscous, flowable material into an overflow channel;

overflowing the viscous, flowable material in a controlled manner to form a second sheet-like flow;

fusing the second sheet-like flow with a surface of the first sheet-like flow to form a laminated flow; and

drawing the laminated flow into a laminated sheet.

59. A method of making a laminated sheet, comprising:

supplying a first and a second viscous, flowable material into independent compartments in an overflow channel;

simultaneously overflowing the first and second viscous, flowable materials to form separate flow streams;

uniting the separate flow streams into a single sheet-like laminated flow; and

drawing the sheet-like laminated flow into a laminated sheet.

60. A method of making a laminated sheet, comprising:

drawing a first viscous, flowable material through a slot to form a first sheet-like flow;

supplying a second viscous, flowable material into an overflow channel and overflowing the second viscous, flowable material from the overflow channel in a controlled manner to form a second sheet-like flow having an untouched surface of fire-polished quality;

merging the second sheet-like flow with a surface of the first sheet-like flow to form a laminated flow; and

drawing the laminated flow into a laminated sheet.

61. A method of making a laminated sheet, comprising:

supplying a viscous, flowable material into an open channel;

simultaneously overflowing the viscous, flowable material from a first side of the open channel and drawing the viscous, flowable material from a second side of the open channel;

wherein the viscous, flowable material drawn from the second side of the open channel forms a sheet-like flow;

wherein the viscous, flowable material overflowed from the first side of the open channel forms two separate flow streams having untouched surfaces of fire-polished quality;

merging each of the flow streams with a surface of the sheet-like flow to form a laminated flow; and

drawing the laminated flow into a laminated sheet.

62. A method of making a laminated sheet, comprising:

obtaining a sheet of material;

supplying a first viscous, flowable material to a first overflow channel;

overflowing the first viscous, flowable material in a controlled manner to form a sheet-like flow with an untouched surface of fire-polished quality; and

while the sheet-like flow is in viscous, flowable form, merging the sheet-like flow with a surface of the sheet of material to form a laminated sheet.

63. The method of claim 62, further comprising drawing the laminated sheet to a desired thickness.

64. The method of claim 63, further comprising supplying a second viscous, flowable material to a second overflow channel, overflowing the second viscous, flowable material in a controlled manner to form a sheet-like flow with an untouched surface of fire-polished quality, and, while the sheet-like flow is in viscous, flowable form, merging the sheet-like flow with a second surface of the sheet of material.

65. The method of claim 63, wherein the sheet of material comprises an annealed glass.

66. The method of claim 63, wherein the sheet of material comprises an expandable material.

67. The method of claim 63, wherein the sheet of material comprises a glass-ceramic.

68. A method of making a laminated sheet, comprising:

supplying a first viscous, flowable material to a first overflow channel and a second viscous, flowable material to a second overflow channel;

overflowing the first viscous, flowable material from the first overflow channel in a controlled manner to form a first sheet-like flow with at least one untouched surface of fire-polished quality;

overflowing the second viscous, flowable material from the second overflow channel in a controlled manner to form a second sheet-like flow with at least one untouched surface of fire-polished quality;

drawing the first sheet-like flow into a first sheet and the second sheet-like flow into a second sheet;

feeding the first sheet into a float bath and continuously moving the first sheet across the float bath; and

feeding the second sheet into the float bath and merging the second sheet with the first sheet so as to form a continuously moving laminated sheet across the float bath.

69. An apparatus for forming a laminated sheet, comprising:

an overflow means for forming opposed sheet-like flows, the overflow means having at least two independent compartments for receiving a viscous, flowable material;

a forming means positioned below the overflow means for converging and uniting the opposed sheet-like flows into a single drawn sheet flow;

means for pivotally adjusting the overflow means such that a surface of the overflow channel has a desired tilt angle with respect to the horizontal; and

means for delivering a viscous, flowable material into the compartments.

70. An apparatus for forming a laminated sheet, comprising:

an overflow channel for forming opposed sheet-like flows from a viscous, flowable material;

a slotted channel positioned below the overflow channel for forming a drawn sheet-like flow;

a forming body positioned below the overflow channel for converging and uniting the opposed sheet-like flows with outer surfaces of the drawn sheet-like flow to form a laminated flow;

means for pivotally adjusting the overflow channel such that a surface of the overflow channel has a desired tilt angle with respect to the horizontal; and

means for delivering a viscous, flowable material into the overflow channel.

71. The apparatus of claim 70, wherein the slotted channel is fluidly connected to the overflow channel so as to receive viscous, flowable material from the overflow channel.

72. The apparatus of claim 70, further comprising means for delivering a viscous, flowable material to the slotted channel.

73. The apparatus of claim 70, wherein the slotted channel is formed in the forming body.