Variable Transmission Window System

• US 20070285759A1
• Filed: 06/11/2007
• Published: 12/13/2007
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Theiste, David, Cammenga, David, Neuman, George, Turnbull, Robert, Busscher, Bradley, Ash, Kevin
• Granted Patent: US 7,990,603 B2
• Time in Patent Office: Days
• US Class Current: 359/275
• CPC Class Codes: B60J 3/04 adjustable in transparency
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: E06B 9/24 Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blindsoperating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor

Abstract

An electrical control system is disclosed for controlling a plurality of variable transmittance windows. The electrical control system comprises a master control circuit and user input circuits for supplying control signals representing transmittance levels for the variable transmission windows, and a plurality of slave window control circuits coupled to the master control circuit, user input circuits and the variable transmittance windows. Each slave window control circuit controls the transmittance of at least one of the variable transmission windows in response to control signals received from the master control circuit and/or user input circuits. Also disclosed are novel methods for the manufacture of an electrochromic device used in variable transmittance windows. Novel structural features for improving heat transfer away from the windows, shielding the window from external loads, and improving the electrical performance of the windows are also disclosed.

Claims

1. An electrical control system for controlling a variable transmittance window, comprising:

a slave window control circuit coupled to the variable transmittance window; and

a user input mechanism coupled to said slave window control circuit, wherein said user input mechanism is configured to supply control signals representing desired transmittance levels for the variable transmittance window to said slave window control circuit, said slave window control circuit controls the transmittance of the variable transmittance window in response to control signals received from said user input mechanism, said user input mechanism includes lights coupled to said slave window control circuit, said lights providing information to system users, including at least one of;

the current transmittance state of the variable transmittance window, the selected transmittance state of the variable transmittance window, whether the variable transmittance window is currently changing transmittance states, whether said user input mechanism is being overridden, and whether the system is operating properly.

2. The electrical control system of claim 1, wherein an outer surface of said user input mechanism is sealed and comprises a material that is impervious to moisture.

3. The electrical control system of claim 1, wherein said user input mechanism includes a first switch for causing the variable transmission window to darken, and a second switch for causing the variable transmission window to lighten.

4. The electrical control system of claim 3, wherein said lights include backlights for said first and second switches.

5. The electrical control system of claim 4, wherein said backlights are extinguished when said user input mechanism is being overridden.

6. The electrical control system of claim 1, wherein said slave window control circuit includes elements for providing signals and power to said variable transmittance window and said user input mechanism, receiving signals from said variable transmittance window and said user input mechanism, and monitoring power drawn by said variable transmittance window and said user input mechanism.

7. The electrical control system of claim 6, wherein said slave window control circuit monitors a rate of change of current supplied to said variable transmittance window and when the rate of change of current approaches zero, said slave window control circuit causes said lights to indicate that the transmittance state of said variable transmittance window is not changing.

8. The electrical control system of claim 1, wherein said lights include at least three indicator lights for indicating the current transmittance state of the variable transmittance window and for indicating the selected transmittance state of the variable transmittance window, wherein said three indicator lights change appearance to distinguish between the current and the selected transmittance states of the variable transmittance window.

9. The electrical control system of claim 8, wherein said indicator lights change appearance to indicate when the current transmittance state reaches the selected transmittance state.

10. The electrical control system of claim 8, wherein said at least three indicator lights consist of five indicator lights for indicating the current transmittance state of the variable transmittance window and for indicating the selected transmittance state of the variable transmittance window.

11. The electrical control system of claim 8, wherein said slave window control circuit monitors a voltage drop in said lights to determine if one of said lights has failed.

12. The electrical control system of claim 1, wherein said user input mechanism controls the transmittance of more than one variable transmittance window.

13. A mass transit vehicle comprising:

a plurality of variable transmittance windows; and

said electrical control system of claim 1 for controlling said plurality of variable transmittance windows.

14. The mass transit vehicle of claim 13, wherein said mass transit vehicle is an aircraft.

15. An electrical control system for controlling a plurality of variable transmittance windows, comprising:

a plurality of slave window control circuits each for controlling a transmittance of one or more of the plurality of variable transmittance windows;

a plurality of user input mechanisms each coupled to one or more of said slave window control circuits; and

a master control circuit coupled to said plurality of slave window control circuits,

wherein;

said master control circuit and said user input mechanisms are configured to supply transmittance state signals representing transmittance levels for the variable transmittance windows to said slave window control circuits;

each slave window control circuit controls the transmittance of at least one of the variable transmittance windows in response to the transmittance state signals supplied by said master control circuit and/or one of said user input mechanisms;

said master control circuit and slave window control circuits are configured such that when a transmittance state signal is provided to a slave window control circuit by said master control circuit, the transmittance state signal provided by said master control circuit is used by said slave window control circuit to determine the transmittance level of any variable transmittance window to which said slave window control circuit is coupled while overriding any transmittance state signal received from a user input mechanism.

16. The electrical control system of claim 15, wherein each said user input mechanism includes a visual indicator for indicating when said slave window control circuit is operating based on an overriding transmittance state signal provided by said master control circuit.

17. The electrical control system of claim 15, wherein, upon detecting that the transmittance state signal provided by said master control circuit is no longer applied, said slave window control circuit maintains the same state as when overridden unless subsequently changed by said user input mechanism.

18. The electrical control system of claim 15, wherein said master control circuit causes the transmittance of the variable transmittance windows to gradually change states in steps.

19. The electrical control system of claim 15, wherein said master control circuit causes the transmittance of groups of the variable transmittance windows to change sequentially.

20. The electrical control system of claim 15, wherein said master control circuit causes the transmittance of the variable transmittance windows to decrease when in a movie mode.

21. The electrical control system of claim 15, wherein said master control circuit is coupled to said slave window control circuits by a bus.

22. The electrical control system of claim 21, wherein said slave window control circuits are configured to control the transmittance of said variable transmittance windows in response to said user input mechanisms when either said bus or said master control circuit fails.

23. The electrical control system of claim 15, wherein said slave window control circuit also includes circuitry to monitor the system for a reset signal and to short-circuit said variable transmittance window to quickly clear it when a reset signal is detected.

24. The electrical control system of claim 15, wherein said user input mechanisms include lights coupled to said slave window control circuits, said lights providing information to system users, including at least one of:

the current transmittance state of the variable transmittance windows, the selected transmittance state of the variable transmittance windows, whether the variable transmittance windows are currently changing transmittance states, whether said user input mechanisms are being overridden, and whether the system is operating properly.

25. A mass transit vehicle comprising:

a plurality of variable transmittance windows; and

said electrical control system of claim 15 for controlling said plurality of variable transmittance windows.

26. The mass transit vehicle of claim 25, wherein said mass transit vehicle is an aircraft.

27. An electrical control system for controlling a plurality of variable transmittance windows, comprising:

a slave window control circuit coupled to the variable transmittance window, wherein said slave window control circuit comprises dropout detection circuitry to determine if power has been lost, determine for how long power has been lost, and return the variable transmittance window to its most recent state if power has been lost for less than a predetermined time.

28. The electrical control system of claim 27 further comprising a user input mechanism coupled to said slave window control circuit, wherein said user input mechanism is configured to supply control signals representing a desired transmittance level for the variable transmittance window to said slave window control circuit, said slave window control circuit controls the transmittance of the variable transmittance window in response to the control signals received from said user input mechanism.

29. The electrical control system of claim 28, wherein said slave window control circuit includes elements for providing signals and power to said variable transmittance window and said user input mechanism, receiving signals from said variable transmittance window and said user input mechanism, and monitoring power drawn by said variable transmittance window and said user input mechanism.

30. The electrical control system of claim 28, wherein said slave window control circuit also includes circuitry to monitor the system for a reset signal and short-circuit said variable transmittance window to quickly clear it when a reset signal is detected.

31. The electrical control system of claim 27, and further comprising a user input mechanism coupled to said slave window control circuit, wherein said user input mechanism is configured to supply control signals representing desired transmittance levels for the variable transmittance window to said slave window control circuit, said slave window control circuit controls the transmittance of, the variable transmittance window in response to control signals received from said user input mechanism, said user input mechanism includes lights coupled to said slave window control circuit, said lights providing information to system users, including at least one of:

the current transmittance state of the variable transmittance window, the selected transmittance state of the variable transmittance window, whether the variable transmittance window is currently changing transmittance states, whether said user input mechanism is being overridden, and whether the system is operating properly.

32. The electrical control system of claim 27, and further comprising:

a plurality of said slave window controls circuits each for controlling a transmittance of one or more of the plurality of variable transmittance windows;

a plurality of user input mechanisms each coupled to one or more of said slave window control circuits; and

a master control circuit coupled to said plurality of slave window control circuits,

wherein;

said master control circuit and said user input mechanisms are configured to supply transmittance state signals representing transmittance levels for the variable transmittance windows to said slave window control circuits;

each slave window control circuit controls the transmittance of at least one of the variable transmittance windows in response to the transmittance state signals supplied by said master control circuit and/or one of said user input mechanisms;

said master control circuit and slave window control circuits are configured such that when a transmittance state signal is provided to a slave window control circuit by said master control circuit, the transmittance state signal provided by said master control circuit is used by said slave window control circuit to determine the transmittance level of any variable transmittance window to which said slave window control circuit is coupled while overriding any transmittance state signal received from a user input mechanism.

33. A mass transit vehicle comprising:

a plurality of variable transmittance windows; and

said electrical control system of claim 27 for controlling said plurality of variable transmittance windows.

34. The mass transit vehicle of claim 33, wherein said mass transit vehicle is an aircraft.

35. An electrical control system for controlling a plurality of variable transmittance windows within a vehicle, comprising:

a slave window control circuit coupled to the variable transmittance window and coupled to receive power from a vehicle power source, said slave window control circuit comprises protection circuitry including circuitry to protect the system against voltage spikes from −

500V to +500V.

36. The electrical control system of claim 35, wherein said protection circuitry comprises a diode to block negative voltage spikes.

37. The electrical control system of claim 36, wherein said protection circuitry further comprises a transistor switch to block positive voltage spikes.

38. The electrical control system of claim 35, wherein said protection circuitry comprises a transistor switch to block positive voltage spikes.

39. The electrical control system of claim 35, wherein said protection circuitry comprises diode protection circuitry on each of the supplies to said variable transmittance windows to protect against excess current.

40. The electrical control system of claim 35, wherein said protection circuitry comprises overvoltage current sink circuitry to absorb excess electrical energy stored in the window.

41. The electrical control system of claim 35, wherein said protection circuitry comprises an enhanced power supply circuit including two separate power supply sections providing different voltages.

42. The electrical control system of claim 35, wherein said slave window control circuit comprises dropout detection circuitry to determine if power has been lost, determine for how long power has been lost, and return the variable transmittance window to its most recent state if power has been lost for less than a predetermined time.

43. The electrical control system of claim 35, and further comprising a user input mechanism coupled to said slave window control circuit, wherein said user input mechanism is configured to supply control signals representing desired transmittance levels for the variable transmittance window to said slave window control circuit, said slave window control circuit controls the transmittance of-T the variable transmittance window in response to control signals received from said user input mechanism, said user input mechanism includes lights coupled to said slave window control circuit, said lights providing information to system users, including at least one of:

the current transmittance state of the variable transmittance window, the selected transmittance state of the variable transmittance window, whether the variable transmittance window is currently changing transmittance states, whether said user input mechanism is being overridden, and whether the system is operating properly.

44. The electrical control system of claim 35, and further comprising:

a plurality of said slave window controls circuits each for controlling a transmittance of one or more of the plurality of variable transmittance windows;

a plurality of user input mechanisms each coupled to one or more of said slave window control circuits; and

a master control circuit coupled to said plurality of slave window control circuits,

wherein;

said master control circuit and said user input mechanisms are configured to supply transmittance state signals representing transmittance levels for the variable transmittance windows to said slave window control circuits;

each slave window control circuit controls the transmittance of at least one of the variable transmittance windows in response to the transmittance state signals supplied by said master control circuit and/or one of said user input mechanisms;

said master control circuit and slave window control circuits are configured such that when a transmittance state signal is provided to a slave window control circuit by said master control circuit, the transmittance state signal provided by said master control circuit is used by said slave window control circuit to determine the transmittance level of any variable transmittance window to which said slave window control circuit is coupled while overriding any transmittance state signal received from a user input mechanism.

45. A mass transit vehicle comprising:

a plurality of variable transmittance windows; and

said electrical control system of claim 35 for controlling said plurality of variable transmittance windows.

46. The mass transit vehicle of claim 45, wherein said mass transit vehicle is an aircraft.

47. A variable transmittance window comprising:

an electrochromic device coupled to control circuitry for varying the transmittance of the electrochromic device, said electrochromic device comprising;

first and second substrates arranged in a parallel, spaced-apart relation to form a chamber between inner surfaces of said substrates;

a transparent electrode coating provided on each of the inner surfaces of said substrates;

first and second layers of silver epoxy respectively deposited on said first and second transparent electrode coatings of said substrates at the perimeter of said substrates; and

an electrochromic medium disposed between said transparent electrode coatings.

48. The variable transmittance window of claim 47 and further comprising silver contact tabs attached to said first and second layers of silver epoxy.

49. The variable transmittance window of claim 47 and further comprising a plurality of conducting structures physically and electrically coupled to said layer of silver epoxy on each of said substrates at the periphery of said substrates at opposite areas of the perimeter, and each conducting structure extends beyond the periphery of said substrates to connect to a conducting material coupled to control circuitry.

50. The variable transmittance window of claim 47, wherein said silver epoxy is dispensed on said first and second transparent electrode coatings by inkjet printing.

51. The variable transmittance window of claim 47, wherein said silver epoxy layers are applied to form a continuous ring around the perimeter of said first and second transparent electrode coatings.

52. The variable transmittance window of claim 47, wherein said silver epoxy layers are applied in multiple areas around the perimeter of said first and second transparent electrode coatings.

53. A mass transit vehicle comprising:

a plurality of variable transmittance windows as defined in claim 47.

54. The mass transit vehicle of claim 53, wherein said mass transit vehicle is an aircraft.

55. A variable transmittance window system, comprising:

a variable transmittance window comprising an electrochromic device coupled to control circuitry for varying the transmittance of said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

56. The variable transmittance window system of claim 55 further comprising an inner reveal and an outer mounting structure that are in physical contact with said middle and outer reveals, and that are configured to secure said middle and outer reveals at their periphery in a fixed position.

57. The variable transmittance window system of claim 55, wherein said electrochromic device comprises:

first and second substrates arranged in a parallel, spaced-apart relation to form a chamber between inner surfaces of said substrates;

a transparent electrode coating provided on each of the inner surfaces of said substrates;

first and second layers of silver epoxy respectively deposited on said first and second transparent electrode coatings of said substrates at the perimeter of said substrates; and

an electrochromic medium disposed between said transparent electrode coatings.

58. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 55.

59. The mass transit vehicle of claim 58, wherein said mass transit vehicle is an aircraft.

60. A variable transmittance window system comprising:

a variable transmittance window comprising an electrochromic device coupled to control circuitry for varying the transmittance of said electrochromic device;

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose, said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

61. The variable transmittance window system of claim 60 further comprising an inner reveal and an outer mounting structure that are in physical contact with said middle and outer reveals, and that are configured to secure said middle and outer reveals at their periphery in a fixed position.

62. The variable transmittance window system of claim 60, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

63. The variable transmittance window system of claim 60, wherein said electrochromic device comprises:

first and second substrates arranged in a parallel, spaced-apart relation to form a chamber between inner surfaces of said substrates;

a transparent electrode coating provided on each of the inner surfaces of said substrates;

first and second layers of silver epoxy respectively deposited on said first and second transparent electrode coatings of said substrates at the perimeter of said substrates; and

an electrochromic medium disposed between said transparent electrode coatings.

64. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 60.

65. The mass transit vehicle of claim 64, wherein said mass transit vehicle is an aircraft.

66. A variable transmittance window system, comprising:

a variable transmittance window comprising an electrochromic device comprising;

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first electrically conductive coating provided on the second surface of said first substrate;

a second electrically conductive coating provided on the first surface of said second substrate; and

an electrochromic medium disposed between said electrically conductive coatings; and

a control circuit coupled to said electrochromic device for controlling the transmittance thereof, wherein said control circuit applies a positive voltage to decrease the transmittance of said electrochromic device and applies a sequence of negative voltage pulses to said variable transmittance window while short-circuiting said variable transmittance window during other times to increase the transmittance of said electrochromic device.

67. The variable transmittance window system of claim 66, wherein at least one of the negative voltage pulses has a duration that is at least twice as long as the duration preceding the next negative voltage pulse.

68. The variable transmittance window system of claim 66, wherein said control circuit applies a sequence of negative voltage pulses of decreasing duration to said variable transmittance window.

69. The variable transmittance window system of claim 66, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second electrically conductive coatings at the perimeter of said substrates.

70. The variable transmittance window system of claim 66 and further comprising:

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose, said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

71. The variable transmittance window system of claim 66 and further comprising a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

72. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 66.

73. The mass transit vehicle of claim 72, wherein said mass transit vehicle is an aircraft.

74. A variable transmittance window system comprising:

an electrochromic element comprising;

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first electrically conductive coating provided on the second surface of said first substrate;

a second electrically conductive coating provided on the first surface of said second substrate;

an electrochromic medium disposed between said electrically conductive coatings;

a first electrically conductive structure electrically coupled to said first electrically conductive coating at said first side of said first substrate;

a second electrically conductive structure electrically coupled to said first electrically conductive coating at said second side of said first substrate;

a third electrically conductive structure electrically coupled to said second electrically conductive coating at said first side of said second substrate; and

a fourth electrically conductive structure electrically coupled to said second electrically conductive coating at said second side of said second substrate,

wherein each of said electrically conductive structures may receive an applied voltage independent of the other electrically conductive structures.

75. The variable transmittance window system of claim 74 and further comprising a control circuit for controlling transmittance of said electrochromic device by independently applying voltages to said electrically conductive structures.

76. The variable transmittance window system of claim 74, wherein, when increasing the transmittance of said electrochromic device, said control circuit applies a negative voltage pulse to said electrochromic device and then short circuits said electrochromic device.

77. The variable transmittance window system of claim 74, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage.

78. The variable transmittance window system of claim 74, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage for a first predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a second predetermined time period, then couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a third predetermined time period.

79. The variable transmittance window system of claim 78, wherein, when decreasing the transmittance of said electrochromic device, said control circuit subsequently couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fourth predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fifth predetermined time period.

80. The variable transmittance window system of claim 74, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second electrically conductive coatings at the perimeter of said substrates.

81. The variable transmittance window system of claim 74 and further comprising:

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose, said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

82. The variable transmittance window system of claim 74 and further comprising a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

83. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 74.

84. The mass transit vehicle of claim 83, wherein said mass transit vehicle is an aircraft.

85. An electrochromic element comprising:

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first layer of ITO provided on the second surface of said first substrate having a thickness of at least two waves and having a sheet resistance of less than about 2.6 ohms/square;

a second layer of ITO provided on the first surface of said second substrate; and

an electrochromic medium disposed between said first and second layers of ITO.

86. The electrochromic element of claim 85, wherein said second layer of ITO has a thickness of at least two waves and a sheet resistance of less than about 2.6 ohms/square.

87. The electrochromic element of claim 86, wherein said second layer of ITO has a sheet resistance of less than about 2.0 ohms/square.

88. The electrochromic element of claim 85, wherein said first layer of ITO has a sheet resistance of less than about 2.0 ohms/square.

89. The electrochromic element of claim 85, wherein said first substrate and said first layer of ITO exhibit a transmission of at least 65% when incorporated into the electrochromic element.

90. The electrochromic element of claim 85, wherein said second substrate and said second layer of ITO exhibit a transmission of at least 65% when incorporated into the electrochromic element.

91. The electrochromic element of claim 85, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second layers of ITO at the perimeter of said substrates.

92. A mass transit vehicle comprising:

a plurality of electrochromic elements as defined in claim 85.

93. The mass transit vehicle of claim 92, wherein said mass transit vehicle is an aircraft.

94. A variable transmittance window system, comprising:

a variable transmittance window comprising an electrochromic device comprising;

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first electrically conductive coating provided on the second surface of said first substrate;

a second electrically conductive coating provided on the first surface of said second substrate; and

an electrochromic medium disposed between said electrically conductive coatings; and

a control circuit coupled to said electrochromic device for controlling the transmittance thereof,

wherein said variable transmittance window system is configured such that said electrochromic device transitions from 60% transmittance to less than about 0.2% transmittance in less than about 2 minutes.

95. The variable transmittance window system of claim 94, wherein said electrochromic device further comprises:

a first electrically conductive structure electrically coupled to said first electrically conductive coating at a first side of said first substrate;

a second electrically conductive structure electrically coupled to said first electrically conductive coating at a second side of said first substrate opposite said first side;

a third electrically conductive structure electrically coupled to said second electrically conductive coating at a first side of said second substrate; and

a fourth electrically conductive structure electrically coupled to said second electrically conductive coating at a second side of said second substrate opposite said first side,

wherein said control circuit controls the transmittance of said electrochromic device by independently applying voltages to said electrically conductive structures.

96. The variable transmittance window system of claim 95, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage.

97. The variable transmittance window system of claim 95, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage for a first predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a second predetermined time period, then couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a third predetermined time period.

98. The variable transmittance window system of claim 97, wherein, when decreasing the transmittance of said electrochromic device, said control circuit subsequently couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fourth predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fifth predetermined time period.

99. The variable transmittance window system of claim 94, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second electrically conductive coatings at the perimeter of said substrates.

100. The variable transmittance window system of claim 94 and further comprising:

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

101. The variable transmittance window system of claim 94 and further comprising a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

102. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 94.

103. The mass transit vehicle of claim 102, wherein said mass transit vehicle is an aircraft.

104. A variable transmittance window system, comprising:

a variable transmittance window comprising an electrochromic device having an area larger than 0.1 m², said electrochromic device comprising;

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first electrically conductive coating provided on the second surface of said first substrate;

a second electrically conductive coating provided on the first surface of said second substrate; and

an electrochromic medium disposed between said electrically conductive coatings; and

a control circuit coupled to said electrochromic device for controlling the transmittance thereof,

wherein said variable transmittance window system is configured such that said electrochromic device transitions from 60% transmittance to less than about 0.2% transmittance.

105. The variable transmittance window system of claim 104, wherein said electrochromic device further comprises:

a first electrically conductive structure electrically coupled to said first electrically conductive coating at a first side of said first substrate;

a second electrically conductive structure electrically coupled to said first electrically conductive coating at a second side of said first substrate opposite said first side;

a third electrically conductive structure electrically coupled to said second electrically conductive coating at a first side of said second substrate; and

a fourth electrically conductive structure electrically coupled to said second electrically conductive coating at a second side of said second substrate opposite said first side,

wherein said control circuit controls the transmittance of said electrochromic device by independently applying voltages to said electrically conductive structures.

106. The variable transmittance window system of claim 105, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage.

107. The variable transmittance window system of claim 105, wherein, when decreasing the transmittance of said electrochromic device, said control circuit couples said first and second electrically conductive structures to ground and couples said third and fourth electrically conductive structures to a positive voltage for a first predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a second predetermined time period, then couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a positive voltage, and said fourth electrically conductive structure to a high impedance for a third predetermined time period.

108. The variable transmittance window system of claim 107, wherein, when decreasing the transmittance of said electrochromic device, said control circuit subsequently couples said first electrically conductive structure to ground, said second electrically conductive structure to a high impedance, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fourth predetermined time period, then couples said first electrically conductive structure to a high impedance, said second electrically conductive structure to ground, said third electrically conductive structure to a high impedance, and said fourth electrically conductive structure to a positive voltage for a fifth predetermined time period.

109. The variable transmittance window system of claim 104, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second electrically conductive coatings at the perimeter of said substrates.

110. The variable transmittance window system of claim 104 and further comprising:

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose, said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

111. The variable transmittance window system of claim 104 and further comprising a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

112. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 104.

113. The mass transit vehicle of claim 112, wherein said mass transit vehicle is an aircraft.

114. A variable transmittance window system, comprising:

a variable transmittance window comprising an electrochromic device comprising;

a first substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a second substrate having a first surface, a second surface, and a perimeter defining a first side and a second side opposite said first side;

a first electrically conductive coating provided on the second surface of said first substrate;

a second electrically conductive coating provided on the first surface of said second substrate; and

an electrochromic medium disposed between said electrically conductive coatings; and

a control circuit coupled to said electrochromic device for controlling the transmittance thereof,

wherein said variable transmittance window system is configured such that said electrochromic device transitions from 0.2% transmittance to more than about 60% transmittance in less than about 5 minutes.

115. The variable transmittance window system of claim 114, wherein, when increasing the transmittance of said electrochromic device, said control circuit applies a negative voltage pulse to said electrochromic device and then short circuits said electrochromic device.

116. The variable transmittance window system of claim 115, wherein said control circuit applies a sequence of negative voltage pulses to said variable transmittance window while short-circuiting said variable transmittance window during other times to increase the transmittance of said electrochromic device.

117. The variable transmittance window system of claim 115, wherein said control circuit applies a sequence of negative voltage pulses of decreasing duration to said variable transmittance window.

118. The variable transmittance window system of claim 114, wherein said electrochromic device comprises first and second layers of silver epoxy respectively deposited on said first and second electrically conductive coatings at the perimeter of said substrates.

119. The variable transmittance window system of claim 114 and further comprising:

an elastomeric bezel in contact with, and enclosing the perimeter of, said electrochromic device; and

a middle reveal and an outer reveal that are in physical contact with, and enclose, said elastomeric bezel around its perimeter, and that are configured to retain the electrochromic device in a fixed position.

120. The variable transmittance window system of claim 114 and further comprising a middle reveal and an outer reveal that are in physical contact with said electrochromic device around its perimeter, and that are configured to retain the electrochromic device in a fixed position, wherein said middle and outer reveals are made of a thermally conductive plastic so that thermal energy from said electrochromic device is conducted into other structures in contact with said middle and outer reveals.

121. A mass transit vehicle comprising:

a plurality of the variable transmittance window systems as defined in claim 114.

122. The mass transit vehicle of claim 121, wherein said mass transit vehicle is an aircraft.