Embossing method and apparatus

• US 20050150589A1
• Filed: 05/13/2003
• Published: 07/14/2005
• Est. Priority Date: 05/13/2002
• Status: Active Grant

• Current Assignee: New Vision Display, Inc.
• Original Assignee: Displaydata Ltd.
• Inventors: Jones, John C, Amos, Richard M, Wood, Emma L, Bryan-Brown, Guy P, Worthing, Philip T
• Granted Patent: US 7,824,516 B2
• Time in Patent Office: Days
• US Class Current: 156/209
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29C 35/0894 provided with masks or diaphragms
• CPC Class Codes: B29C 39/148 characterised by the shape of the surface
• CPC Class Codes: B29C 43/222 characterised by the shape of the surface
• CPC Class Codes: B29C 59/046 for layered or coated substantially flat surfaces
• CPC Class Codes: B29K 2105/0079 Liquid crystals
• CPC Class Codes: G02F 1/13378 by treatment of the surface, e.g. embossing, rubbing or light irradiation G02F1/133711, G02F1/133734, G02F1/133753 take precedence
• CPC Class Codes: G02F 1/1341 Filling or closing of cells
• CPC Class Codes: Y10T 156/1023 Surface deformation only [e.g., embossing]
• CPC Class Codes: Y10T 156/1737 Discontinuous, spaced area, and/or patterned pressing

Abstract

A method and apparatus for forming a patterned layer having a surface profile that provides relief structures within an electronic device. The method comprises the steps of taking a carrier film (50) having an inverse of the required surface profile formed on one side thereof, taking a layer of fixable material (54) located on a substrate (52), laminating the carrier film (50) and substrate (52) such the carrier film causes the required surface profile to be formed in the layer of fixable material with a predetermined offset, and then fixing the fixable material. Lamination may be performed using rollers (56,58) or a vacuum process. The process is designed to ensure that the offset can be kept as low as possible, preferably to within 150 nm.

Claims

1. A method of embossing a layer of fixable material with a surface profile comprising the steps of;

a) taking a carrier film having an inverse of the required surface profile formed on one side thereof,

b) taking a layer of fixable material located on a substrate that comprises an electrode,

c) laminating the carrier film and substrate such the carrier film causes the required surface profile to be formed in the layer of fixable material, and

d) fixing the fixable material,

wherein the method is performed such that the offset of the surface profile divided by the relative permittivity of the fixable material is less than 1000 nm.

2. A method according to claim 1 and further comprising the step, after the step of fixing the fixable material is performed, of removing the carrier film from the layer of fixable material.

3. A method according to claim 1 wherein the fixable material weakly adheres to the side of the carrier film carrying the inverse of the required surface profile to facilitate removal of the carrier film from the fixed layer of fixable material.

4. A method according to claim 1 wherein at least one additional layer is interposed between the layer of fixable material and the carrier film prior to lamination.

5. A method according to claim 1 wherein the substrate is formed from a brittle material.

6. A method according to claim 1 wherein the fixable material is a resin that is curable using ultra-violet radiation.

7. A method according to claim 1 wherein the viscosity of the fixable material is less than 20 μ

s.

8. A method according to claim 7 wherein the viscosity of the fixable material is less than 500 cPs.

9. A method according to claim 1 wherein the viscosity of the fixable material is greater than 0.1 cps.

10. A method according to claim 9 wherein the viscosity of the fixable material is greater than 5 cps.

11. A method according to claim 10 wherein the viscosity of the fixable material is greater than 50 cps.

12. A method according to claim 1 wherein the pressure applied during lamination is between 0.002 N/mm² and 100 N/mm².

13. A method according to claim 1 wherein the offset of the surface profile divided by the relative permittivity of the fixable material is less than 100 nm.

14. A method according to claim 13 wherein the offset of the surface profile divided by the relative permittivity of the fixable material is less than 50 nm.

15. A method according to claim 14 wherein the offset of the surface profile divided by the relative permittivity of the fixable material is less than 10 nm.

16. A method according to claim 1 wherein, during the lamination step, the carrier film is brought into contact with the substrate carrying the layer of fixable material and passed through a means of applying the pressure required for lamination.

17. A method according to claim 16 wherein a sensing means is provided to monitor the surface profile formed in the layer of fixable material after it has passed through the means of applying the pressure required for lamination.

18. A method according to claim 17 wherein the pressure applied during lamination is adjusted in response to the output of the sensing means to ensure the required surface profile is formed in the layer of fixable material.

19. A method according to claim 16 wherein the means of applying the pressure required for lamination comprises at least one lamination roller.

20. A method according to any of claim 19 wherein the means of applying the pressure required for lamination comprises a first lamination roller in contact with the carrier film and a second lamination roller in contact with the side of the substrate not carrying the layer of fixable material, the first and second lamination rollers being biased toward one another.

21. A method according to claim 19 wherein at least one lamination roller is deformable.

22. A method according to claim 19 wherein at least one lamination roller comprises rubber.

23. A method according to claim 19 wherein at least one lamination roller has a Shore hardness in the range of 50 to 90.

24. A method according to claim 19 wherein the radius of the lamination roller is greater than 1 cm.

25. A method according to claim 19 wherein the radius of the lamination roller is less than 1 m.

27. A method according to claim 16 wherein the substrate carrying the layer of fixable material is passed through the means of applying the pressure required for lamination at a linear speed greater than 0.1 mm per second.

28. A method according to claim 16 wherein the substrate carrying the layer of fixable material is passed through the means of applying the pressure required for lamination at a linear speed less than 100 cm per second.

29. A method according to claim 1 wherein the lamination step is performed by biasing the carrier film toward the substrate using gas pressure.

30. A method according to claim 1 and comprising the additional step of forming the carrier film using a patterned roller.

31. A method according to claim 1 wherein the carrier film comprises any one of PET, PC, and PMMA.

32. A method according to claim 1 wherein the surface profile formed in the fixable material is suitable to provide bistable alignment of liquid crystal material in a liquid crystal device.

33. A method according to claim 1 wherein the surface profile formed in the fixable material is suitable to provide zenithal bistable alignment of liquid crystal material in a liquid crystal device

34. A method according to claim 1 wherein the amplitude of the embossed surface profile is less than 50 μ

m.

35. A method according to claim 1 wherein the amplitude of the embossed surface profile is greater than 0.1 μ

m.

36. A method according to claim 1 wherein the width of the features of the embossed surface profile is less than 100 μ

m.

37. A method according to claim 1 wherein the width of the features of the embossed surface profile is greater than 0.1 μ

m.

38. Apparatus for implementing the method as claimed in claim 1.

46. An electronic device comprising an embossed structure fabricated using the method as claimed in claim 1.

47. An electro-optic device comprising an embossed structure fabricated using the method as claimed in claim 1.

48. An organic semiconductor device comprising an embossed structure fabricated using the method as claimed in claim 1.

49. An organic light emitting diode comprising an embossed structure fabricated using the method as claimed in claim 1.

26. A method according to claim wherein the carrier film is removed from the fixed fixable layer using at least one separation roller and the fixing step is performed by applying the appropriate treatment in a region between the at least lamination roller and the at least one separation roller.

39. A method of forming a layer having a surface profile that provides surface alignment to liquid crystal material comprising the steps of;

a) taking a carrier film having an inverse of the required surface profile formed on one side thereof, b) taking a layer of fixable material located on a substrate, c) laminating the carrier film and substrate such the carrier film causes the required surface profile to be formed in the layer of fixable material with a predetermined offset, and d) fixing the fixable material.

40. An apparatus for forming a layer having a surface profile that provides surface alignment to liquid crystal material, comprising lamination means configured to receive a carrier film having an inverse of the required surface profile formed on one side thereof and to engage said carrier film with a layer of fixable material located on a substrate with sufficient pressure such that an impression of the required surface profile is formed in the layer of fixable material with a predetermined offset.

41. An apparatus as claimed in claim 40 wherein the lamination means comprises a pair of deformable rollers to engage the carrier film with the layer of fixable material located on the substrate.

42. An apparatus as claimed in claim 41 wherein at least one of the deformable rollers comprises rubber.

43. An apparatus as claimed in claim 40 wherein at least one of the deformable rollers has a shore hardness within the range of 50 to 90.

44. An apparatus as claimed in claim 40 and additionally comprising means for fixing the fixable material.

45. A liquid crystal alignment layer comprising a surface profile formed in a layer of fixable material and having a predetermined offset.

50. A method of producing a semiconductor device comprising the step of embossing a structure to constrain a subsequently deposited semiconductor material.

51. A method according to claim 50 wherein an OLED or transistor is produced.