Process and apparatus for microreplication

1. A method of embossing a sheet material, the method comprising:

pressing a patterned tool against the sheet; and

while maintaining the pressing, radiantly heating the sheet, using near-infrared radiant energy from a radiant energy source;

wherein the radiantly heating includes passing the radiant energy through a relatively radiantly-transparent solid material in contact with the sheet; and

wherein the heating includes softening at least part of the sheet.

2. The method of claim 1 , wherein the radiantly-transparent material includes at least part of the tool.

3. The method of claim 2 , wherein the tool is a quartz tool.

4. The method of claim 1 , wherein the radiantly-transparent material is at least a part of a roller that contacts the sheet.

5. The method of claim 4 , wherein the radiantly-transparent material surrounds the radiant energy source.

6. The method of claim 4 , wherein the roller is interposed between the radiant energy source and the sheet.

7. The method of claim 6 , wherein the radiantly heating includes focusing of the radiant energy by the roller.

8. The method of claim 1 , wherein the radiant energy source includes a blackbody emitter, wherein the blackbody emitter has a temperature of at least 2000 K.

9. The method of claim 1 , wherein the sheet material is an oriented material that maintains its oriented character throughout the embossing.

10. A method of embossing a sheet material, the method comprising:

radiantly heating a relatively radiantly-absorptive portion of the sheet, using radiant energy from a radiant energy source;

pressing a patterned tool against the relatively radiantly-absorptive portion of the sheet, wherein the pressing includes patterning a surface of the sheet; and

separating the tool from the surface;

wherein the heating includes passing the radiant energy through a relatively radiantly-transparent portion of the sheet before absorbing the radiant energy in the relatively radiantly-absorptive portion of the sheet;

wherein the relatively radiantly-transparent portion has a lower absorptivity of the radiant energy than does the relatively radiantly-absorptive portion;

wherein the radiantly heating, the pressing, and the separating, are all performed as parts of a roll-to-roll process; and

wherein the tool is part of a patterned belt that includes a patterned tool surface and a flexible backing.

11. A method of embossing a sheet material, the method comprising:

radiantly heating a relatively radiantly-absorptive portion of the sheet, using radiant energy from a radiant energy source;

pressing a patterned tool against the relatively radiantly-absorptive portion of the sheet, wherein the pressing includes patterning a surface of the sheet; and

separating the tool from the surface;

wherein the heating includes passing the radiant energy through a relatively radiantly-transparent portion of the sheet before absorbing the radiant energy in the relatively radiantly-absorptive portion of the sheet;

wherein the relatively radiantly-transparent portion has a lower absorptivity of the radiant energy than does the relatively radiantly-absorptive portion;

wherein the radiantly heating, the pressing, and the separating, are all performed as parts of a roll-to-roll process; and

wherein the radiantly heating includes passing the radiant energy through a radiantly-transparent roller.

12. The method of claim 11 , wherein the passing the energy through the roller includes focusing the radiant energy.

13. The method of claim 10 , wherein the portions of the sheet both include a radiantly-transparent material, and wherein the relatively radiantly-absorptive portion includes a dopant that increases radiant absorptivity.

14. The method of claim 13 , wherein the dopant is substantially-uniformly distributed within a surface layer of the sheet.

15. The method of claim 13 , wherein the dopant is distributed in a non-uniform pattern within a surface layer of the sheet.

16. The method of claim 10 , wherein the portions of the sheet include different materials.

17. The method of claim 10 , further comprising, prior to the heating, forming the sheet;

wherein the forming includes unevenly doping the sheet with a dopant.

18. The method of claim 17 , wherein the unevenly doping includes coating a surface of the sheet with the dopant.

19. The method of claim 17 , wherein the unevenly doping includes impregnating a surface of the sheet with the dopant.

20. The method of claim 17 , wherein the doping includes patterned doping.

21. The method of claim 10 , further comprising, prior to the heating, forming the sheet;

wherein the forming includes coating a surface of the sheet with a dopant.

22. The method of claim 10 , further comprising, prior to the heating, forming the sheet;

wherein the forming includes co-extruding the portions of the sheet material.

23. The method of claim 10 , wherein the heating includes reflecting at least part of the radiant heat off of a reflector.

24. The method of claim 23 , wherein the heating includes unevenly heating the sheet, wherein the unevenly heating is due at least in part to uneven distribution of a dopant within the sheeting.

25. The method of claim 10 , wherein radiantly heating includes melting at least part of the relatively radiantly-absorptive portion of the sheet.

26. A method of embossing a sheet material, the method comprising:

radiantly heating a relatively radiantly-absorptive portion of the sheet, using radiant energy from a radiant energy source;

pressing a patterned tool against the relatively radiantly-absorptive portion of the sheet, wherein the pressing includes patterning a surface of the sheet; and

separating the tool from the surface;

wherein the heating includes passing the radiant energy through a relatively radiantly-transparent portion of the sheet before absorbing the radiant energy in the relatively radiantly-absorptive portion of the sheet;

wherein the relatively radiantly-transparent portion has a lower absorptivity of the radiant energy than does the relatively radiantly-absorptive portion; and

wherein radiantly heating includes softening at least part of the relatively radiantly-absorptive portion of the sheet.

27. The method of claim 10 , wherein the pressing the patterned tool against the sheet commences prior to the radiantly heating.

28. The method of claim 10 , wherein the sheet material is an oriented material that maintains its oriented character throughout the embossing.

29. The method of claim 10 , further comprising, after the heating, cooling the sheet;

wherein the cooling occurs prior to the separating.

30. The method of claim 10 , wherein the radiant energy source includes a blackbody emitter wherein the blackbody emitter has a temperature of at least 2000 K.

31. The method of claim 10 , wherein the tooling includes a reflective material, and wherein the heating includes passing at least some of the radiant energy through the sheet a second time, after reflection off the reflective material.

32. The method of claim 10 , wherein the pressing includes pressing patterned tools against opposite major surfaces of the sheet.

33. The method of claim 10 , wherein the sheet material has a layered structure that is maintained during the heating and the pressing.

34. The method of claim 10 , wherein the heating and the pressing overlap in time.

35. The method claim 10 , wherein the sheet material is constrained between belts during the heating and the pressing.

36. A method of embossing a sheet material, the method comprising:

heating a patterned tool, using radiant energy from a radiant energy source;

pressing the patterned tool against a surface of the sheet, thereby patterning the surface of the sheet; and

separating the tool from the surface;

wherein the sheet material is relatively radiantly transparent;

wherein the heating includes passing the radiant energy through the sheet before absorbing the radiant energy in the patterned tool; and

wherein the sheet material has a lower absorptivity, relative to an absorptivity of the patterned tool;

further comprising heating an additional patterned tool using the radiant energy from the radiant energy source;

wherein the heating the additional patterned tool includes directly heating the additional patterned tool without passing the radiant energy through the sheet material.

37. The method of claim 36 , wherein the radiantly heating, the pressing, and the separating, are all performed as parts of a roll-to-roll process.

38. The method of claim 36 , wherein the pressing the patterned tool against the sheet commences prior to the radiantly heating.

39. The method of claim 36 , further comprising, after the heating, cooling the sheet;

wherein the cooling occurs prior to the separating.

40. The method of claim 36 , wherein the radiant energy source includes a blackbody emitter, wherein the blackbody emitter has a temperature of at least 2000 K.

41. A method of embossing a sheet material, the method comprising:

heating a patterned tool, using radiant energy from a radiant energy source;

pressing the patterned tool against a surface of the sheet, thereby patterning the surface of the sheet; and

separating the tool from the surface;

wherein the sheet material is relatively radiantly transparent;

wherein the heating includes passing the radiant energy through the sheet before absorbing the radiant energy in the patterned tool;

wherein the sheet material has a lower absorptivity, relative to an absorptivity of the patterned tool;

wherein the heating further includes passing the radiant energy through a relatively radiantly transparent roller; and

wherein the passing the energy through the roller includes focusing the radiant energy.

42. The method of claim 36 , wherein the sheet material is an oriented material that maintains its oriented character throughout the embossing.

43. The method of claim 36 , wherein the pressing includes pressing patterned tools against opposite major surfaces of the sheet.

44. The method of claim 36 , wherein the sheet material has a layered structure that is maintained during the heating and the pressing.

45. The method of claim 36 , wherein the heating and the pressing overlap in time.

46. The method of claim 36 , wherein the sheet material is constrained between belts during the heating and the pressing.

47. The method of claim 1 , wherein the heating includes melting the at least part of the sheet.