Heatable article having a configured heating member

• US 7,132,625 B2
• Filed: 10/03/2002
• Issued: 11/07/2006
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Vitro Flat Glass LLC (Compagnie De Saint-Gobain)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Voeltzel, Charles S.
• Primary Examiner(s): Evans, Robin
• Assistant Examiner(s): FASTOVSKY, LEONID M
• Application Number:
  US10/264,106
• Publication Number:
  US 20040065651A1
• Time in Patent Office: 1,496 Days
• Field of Search: 219/19, 219/203, 219/522, 219/543, 219/544, 219/548, 219/219, 219/528, 296/11, 428/34, 428/174, 359/894, 359/603, 359/512, 338/306, 338/307, 338/308, 338/309, 343/704, 343/713
• US Class Current: 219/203
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10192 patterned in the form of columns or grids
• CPC Class Codes: B32B 17/10293 Edge features, e.g. inserts or holes
• CPC Class Codes: H05B 2203/008 with layout including a portion free of resistive material, e.g. communication window
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 3/86 the heating conductors being embedded in the transparent or reflecting material H05B3/845 takes precedence

Abstract

A heatable article, e.g. a heatable windshield, having a generally trapezoidal shape has a conductive member, e.g. a conductive coating, between and in contact with a pair of spaced bus bars having different lengths. Selected portions of the coating between the bus bars are segmented to reduce the difference in watt density between the coatings at the bus bars when current moves through the coating. In one non-limiting embodiment, the width of the segments at the longer bus bar is less than the width of the segments at the longer bus bar. With this configuration, the watt density at the bottom of the windshield is increased to more efficiently remove ice and snow. In another non-limiting embodiment, the coating has a communication window to pass frequencies of the electromagnetic spectrum, e.g. RF frequencies, to obtain information from within the vehicle. The coating surrounding the conductive window has break lines to segment the coating to eliminate hot spot around the periphery of the communication window.

Claims

1. A heatable article comprising:

a first continuous bus bar having a length;

a second continuous bus bar having a length spaced from the first bus bar, wherein the second bus bar is shorter in length than the first bus bar;

an electrically conductive member, wherein portion of the conductive member between the first and second bus bars comprises a plurality of spaced electrically conductive segments in physical and electrical contact with the first and second bus bars;

an electrically conductive segment defined as an intermediate segment between adjacent segments of the plurality of conductive segments, the intermediate segment in electrical contact with one of the bus bars and electrically isolated from the other one of the bus bars to prevent current from moving from one of the bus bars through the intermediate segment to the other one of the bus bars, and at least one of the segments selected from the group of the intermediate segment, the plurality of segments and combinations thereof having varying width as the distance from the first bus bar toward the second bus bar increases, wherein length of the portion of the conductive member between the first and second bus bars and adjacent the first bus bar is greater than length of the portion of the conductive member between the first and second bus bars and adjacent the second bus bar, and the length of the portion of the conductive member between the first and second bus bars continuously decreases as the distance from the first bus bar increases, wherein the length of the conductive member is measured between ends of a bus bar.

2. The heatable article according to claim 1 wherein the segment having varying width is selected from the plurality of segments.

3. The heatable article according to claim 1 further comprising a sheet having a peripheral edge and a major surface within the peripheral edge, wherein the electrically conductive member are within and spaced from the peripheral edge of the sheet.

4. A heatable article comprising;

a first continuous bus bar having a length;

a second continuous bus bar having a length spaced from the first bus bar, wherein the first bus bar is longer in length than the second bus bar;

a first plurality of discreet electrically conductive segments;

a second plurality of discreet electrically conductive segments, the first and second plurality of conductive segments between and in electric contact with the first and second bus bars and the width of the first plurality of conductive segments continuously increases as the distance from the first bus bar increases and the width of the second plurality of conductive segments is substantially constant from the first bus bar to the second bus bar, wherein total width of the first and second plurality of conductive segments at the first bus bar is greater than the total width of the first and second plurality of conductive segments at the second bus bar, and the total width of the first and second plurality of conductive segments continuously decreases as the distance from the first bus bar increases.

5. The heatable article according to claim 4 further comprising a sheet having a peripheral edge and a major surface within the peripheral edge, wherein the first and second segments are within and spaced from the peripheral edge of the sheet.

6. A heatable article comprising:

a pair glass sheets;

at least one plastic sheet between the pair of glass sheets securing the glass sheets together;

a first and a second bus bar between the glass sheets and spaced from one another, wherein the first bus bar is longer than the second bus bar;

an electrically conductive member between the glass sheets, and between and in electric contact with the first and second bus bars;

the conductive member having at least two spaced discreet segments between and in electric contact with the first and second bus bars defined as first and second segments and a third conductive segment between the first and second segments, wherein the third segment is electrically isolated from the first and second segments and in electrical contact with only the first bus bar and the watt density of the conductive member adjacent the first bus bar is at least 80% of the watt density of the conductive member adjacent the second bus bar.

7. The heatable article according to claim 6 wherein the watt density of the conductive member adjacent the first bus bar is at least 90% of the watt density of the conductive member adjacent the second bus bar.

8. The heatable article according to claim 7 wherein the watt density of the conductive member adjacent the first bus bar is at least 95% of the watt density of the conductive member adjacent the second bus bar.

9. The heatable article according to claim 6 wherein the article is an automotive transparency and the conductive member is a coating having a conductive film between a pair of dielectric films and the third segment is electrically isolated from the first and second segments by one or more deletion lines extending at least through the conductive film.

10. The automotive transparency according to claim 9 wherein end portions of the first and second bus bars are closer together than the portions of the bus bars between their end portions.

11. The automotive transparency according to claim 9 wherein the first and second segments are two segments of a plurality of electrically conductive segments, the plurality of segments between the first and second bus bars and wherein at least on one of the segments of the plurality of segments has a width greater at the first bus bar than at the second bus bar.

12. The automotive transparency according to claim 11 wherein the plurality of electrically conductive segments is a first plurality of electrically conductive segments and the third segment is one of a second plurality of electrically conductive segments with a segment of the second group of segments between adjacent segments of the first group of segments, the second group of segments between the first and second bus bars and only in electrical contact with one of the bus bars and electrically isolated from the first group of segments.

13. The automotive transparency according to claim 9 wherein the first and second segments are two segments of a plurality of electrically conductive segments, the plurality of segments between the first and second bus bars and wherein the width of at least on one of the segments of the first plurality of segments at the first and second bus bars is the same.

14. The automotive transparency according to claim 9 wherein the first and second segments are two segments of a plurality of electrically conductive segments, the plurality of segments between the first and second bus bars and wherein at least on one of the segments of the plurality of segments has a width smaller at the first bus bar than at the second bus bar.

15. The automotive transparency according to claim 9 wherein the bus bars and the coating are between a major surface of one of the glass sheets and the plastic sheet.

16. The automotive transparency according to claim 9 wherein the at least one plastic sheet is a first plastic sheet and further including a second plastic sheet with the bus bars and coating between the first and second plastic sheets.

17. The heatable article according to claim 6 wherein the first and second conductive segments is electrically isolated from the third conductive segment by one or more breaker lines.

18. The heatable article according to claim 17 wherein the first and second bus bars are continuous.

19. The heatable article according to claim 6 wherein the first and second bus bars are continuous, the conductive member is spaced from peripheral edge of the sheet and total width of the first, second and third segments at the first bus bar is greater than the total width of the first, second and third segments adjacent the second bus bar and the total width of the first, second and third segments continuously decreases as the distance from the first bus bar increases.

20. A heatable article comprising:

a first continuous bus bar having a length;

a second continous bus bar spaced from the first bus bar, the first bus bar having a length greter than the length of the second bus bar;

an electrically conductive member comprising;

a first plurality of spaced electrically conductive segments;

a second plurality of spaced electrically conductive segments, and

wherein;

a conductive segment of the second plurality of conductive segments is between adjacent ones of the first plurality of conductive segments;

the first plurality of conductive segments are in electric contact with the first and second bus bars, and the second plurality of conductive segments are in electric contact with one of the bus bars and electrically isolated from the other one of the bus bars and the conductive segment of the second plurality of conductive segments between adjacent ones of the first plurality of conductive segments is electrically isolated from adjacent segments of the first plurality of conductive segments to prevent current from moving between the first and second bus bars, and through the second plurality of conductive segments;

at least one of the segments of the first plurality of segments has varying width as the distance from the first bus bar toward the second bus bar increases, and

the total width of the first and second plurality of segments at the second bus bar is greater than the total width of the first and second plurality of segments at the second bus bar and the total width of the first and second plurality of the segments continuously decreases as the distance from the first bus bar increases.

21. The heatable article according to claim 20 wherein the electrically conductive member is continuous from the second bus bar to a position between the bus bars defined as a transition position and the first plurality of spaced electrically conductive segments extend from the transition position to the first bus bar wherein selected ones of the first plurality of spaced electrically conductive segments have decreasing width as the distance from the second bus bar toward the transition position increases.

22. The heatable article according to claim 20 wherein the first plurality of electrically conductive segments extend from the first bus bar to the second bus bar and the width of selected ones of the first plurality of conductive segments increases as the distance from the second bus bar toward the first bus bar increases.

23. The heatable article according to claim 20 wherein the first plurality of electrically conductive segments extend from the first bus bar to the second bus bar and selected ones of the first plurality of conductive segments have a decreasing width from the second bus bar to a position between the first and second bus bars defined as a transition position and an increasing width from the transition position toward the first bus bar.

24. The heatable article according to claim 23 wherein the width of the selected ones of the first plurality of conductive segments at the transition position is less than the width of the selected ones of the first plurality of conductive segments at the second bus bar.

25. The heatable article according to claim 20 wherein the first plurality of electrically conductive segments extend from the first bus bar to the second bus bar and the width of selected ones of the first plurality of conductive segments decreases as the distance from the second bus bar toward the first bus bar increases.

26. The heatable article according to claim 20 further comprising an area between the first and second bus bars defined as a communication window, wherein the resistance within the communication window is greater than the resistance outside and adjacent the communication window.

27. The heatable article according to claim 26 wherein the communication window is adjacent the first bus bar and further comprising a first plurality of spaced deletion lines in the conductive member extending from the second bus bar toward the communication window and a second plurality of deletion lines in the conductive member extending from the first bus bar toward the communication window with the first and second deletion lines extending around portions of the communication window and contacting one another to provide a plurality of electrically isolated portions of the conductive member extending from the first bus bar to the second bus bar and around the portions of the communication window.

28. The heatable article according to claim 20 further comprising a substrate having a major surface wherein the electrically conductive member is a conductive coating applied to the major surface of the substrate and the conductive segment of the second plurality of conductive segments between adjacent ones of the first plurality of conductive segments is electrically isolated from adjacent segments of the first plurality of conductive segments by one or more deletion lines.

29. The heatable article according to claim 28 wherein the conductive coating is a sputtered coating having at least one electrically conductive film between a pair of dielectric films and the deletion lines extend at least through the at least one electrically conductive film.

30. The heatable article according to claim 28 wherein the substrate is a first piece of glass and further comprising:

a second piece of glass;

a plastic sheet between the first and second pieces of glass securing the first and second pieces of glass together with the bus bars and the conductive coating between the first piece of glass and the plastic sheet.

31. The article according to claim 30 wherein the article is a transparence for use on an enclosure of the type selected from the group consisting of a residential home, a commercial building, a space vehicle, an air vehicle, a land vehicle, an over the water vehicle, an under the water vehicle, a refrigerator having a door with a viewing area and combinations thereof.

32. The article according to claim 31 wherein the article is a transparence for an automobile selected from the group consisting of a windshields, side window, back window, moon roof and combinations thereof and the conductive coating is a sputtered coating having at least one electrically conductive film between a pair of dielectric films.

33. The automotive transparency according to claim 32 wherein the automotive transparency is an automotive windshield and the first bus bar is longer than the second bus bar.

34. The automotive transparency according to claim 33 wherein the coating is continuous from the second bus bar to a position between the bus bars defined as a transition position and the first plurality of electrically conductive segments extend from the transition position to the first bus bar wherein selected ones of the first plurality of conductive segments have decreasing width as the distance from the second bus bar increases.

35. The automotive transparency according to claim 33 wherein the second plurality of electrically conductive segments extend from the first bus bar toward the transition position and the width of selected ones of the second plurality of conductive segments decreases as the distance from the first bus bar increases. distance from the first bus bar increases.

36. The automotive transparency according to claim 33 wherein the first plurality of electrically conductive segments extend from the first bus bar to the second bus bar and selected ones of the first plurality of electrically conductive segments have a decreasing width from the first bus bar to a position between the first and second bus bars defined as a transition position and an increasing width from the transition position to the second bus bar.

37. The automotive transparency according to claim 36 wherein the width of the selected ones of the first plurality of conductive segments at the transition position is less than the width of the selected ones of the conductive segments at the first bus bar.

38. The automotive transparency according to claim 33 wherein the second plurality of electrically conductive segments extend from the second bus bar to the first bus bar and the width of selected ones of the second plurality of conductive segments decreases as the distance from the first bus bar increases.

39. The automotive transparency according to claim 33 wherein the first plurality of electrically conductive segments includes a first subgroup of a plurality of electrically conductive segments and a second subgroup of a pllurality of electrically conductive segments, the conductive segments of the first and second subgroups extend from the first bus bar to the second bus bar and the width of the segments of the first subgroup decreases as the distance from the first bus bar increases and the width of the segments of the second subgroup of substantially constant from the first bus bar to the second bus bar.

40. The automotive transparency according to claim 33 further comprising an area between the first and second bus bars defined as a communication window, wherein the resistance within the communiation window is greater than the resistance outside and adjacent the communication window.

41. The automotive transparency according to claim 40 wherein the communiction window is adjacent the first bus bar and further comprising a first plurality of spaced deletion lines in the conductive member extending from the second bus bar toward the conductive member extending from the first bus bar toward the communication window with the first and second deletion lines extending around portions of the communication window and contacting one another to provide a plurality of electrically isolated portions of the conductive member extending from the first bus bar to the second bus bar and around the portions of the communication window.

42. The automotive transparency according to claim 40 further comprising:

a first lead in electric contact with the first bus bar and extending out from between the first and second glass pieces to provide external electrical asccess to the first bus bar, and

a secured lead in electric contact with the second bus bar and extending out from between the first and second glass pieces to provide external electrical access to the second bus bar.

43. The automotive transparency according to claim 40 wherein the conductive member is defined by a perimeter with the perimeter of the conductive member spaced from the periphery of the first glass piece and area between the perimeter of the conductive member and the periphery of the first glass sheet is defined as a non-conductive strip and each end portion of each one of the bus bars extends into the non-conductive strip.

44. The automotive transparency according to claim 40 wherein at least one of the outer major surfaces of one of the glass pieces includes a hydrophobic coating.

45. The automotive transparency according to claim 33 wherein at least one of the outer major surfaces of one of the glass piece includes a photocatalytic coating.

46. The automotive transparency according to claim 33 wherein the plastic sheet is selected from the group of polyvinyl butyral, polyvinyl chloride polyethylene and combinations thereof.

47. The automotive transparency according to claim 33 wherein at least one of the glass sheets or the plastic sheet has a portion in cross section having a wedged shape.

48. The automotive windshield according to claim 33 wherein the first and second bus bars are between the major surface of the first glass piece and the conductive member.

49. The automotive windshield according to claim 33 wherein the first and second bus bars are between the plastic sheet and the conductive member.

50. The heatable article acording to claim 28 wherein the first and second plurality of conductive segments comprise the conductive coating.

51. The heatable article according to claim 20 wherein the first plurality of electrically conductive segments includes a first subgroup of a plurality of electrically conductive segments and a second subgroup of a plurality of electrically conductive segments, the conductive segments of the first and second subgroups extend from the first bus bar to the second bus bar and the width of the segments of the first subgroup decreases as the distance from the first bus bar increases and the width of the segments of the second subgroup is substantially constant from the first bus bar to the second bus bar.

52. The heatable article according to claim 20 wherein selected segments of the first plurality of segments have an increasing width as the distance from the second bus bar increases, and selected segments of the second plurality of segments have a decreasing width as the distance from the second bus bar increases.

53. The heatable article according to claim 20 wherein the second plurality of segments is in electric contact with the second bus bar, electrically isolated from the first bus bar and the conductive segment of the second plurality of conductive segments between adjacent ones of the first plurality of conductive segments is electrically isolated from adjacent segments of the first plurality of segments.

54. The heatable article according to claim 20 wherein the conductive segment of the second plurality of conductive segments between adjacent ones of the first plurality of conductive segments is electrically isolated from adjacent segments of the first plurality of conductive segments by one or more breaker lines.

55. The heatable article according to claim 20 further comprising a sheet having a peripheral edge and a major surface within the peripheral edge, wherein the electrically conductive member is within and spaced from the peripheral edge of the sheet.