Switchable electrochromic devices for use in aircraft transparency windows

• US 20030192991A1
• Filed: 05/12/2003
• Published: 10/16/2003
• Est. Priority Date: 08/03/2000
• Status: Active Grant

• Current Assignee: Chia-Cheng Lin, Thomas G Rukavina
• Original Assignee: Chia-Cheng Lin, Thomas G Rukavina
• Inventors: Lin, Chia-Cheng, Rukavina, Thomas G.
• Granted Patent: US 6,783,099 B2
• Time in Patent Office: Days
• US Class Current: 244/129.3
• CPC Class Codes: B64C 1/1484 Windows B64C1/1492 takes precedence
• CPC Class Codes: B64C 1/1492 Structure and mounting of the transparent elements in the window or windscreen

Abstract

An electrochromic aircraft window assembly includes: a) an outboard pane assembly; and b) a fog preventing electrochromic pane assembly spaced from the outboard pane assembly and defining a chamber therebetween, the fog preventing electrochromic pane assembly having: i) a first substrate having a first surface including a first conductive coating and a second surface including a second conductive coating; ii) a second substrate spaced from the first substrate, the second substrate having a first surface including a third conductive coating, the second surface of the first substrate and the first surface of the second substrate facing each other in spaced-apart relation to define a chamber therebetween; iii) an electrochromic medium contained in the chamber and in contact with the second and the third conductive coatings, the electrochromic medium having a luminous transmittance that varies upon application of an electrical potential through the electrochromic medium; iv) facilities for applying electrical current to the first conductive coating to heat the first conductive coating, thereby preventing fogging of the window assembly; and v) facilities for applying electrical current to the second and the third conductive coatings to establish the electrical potential through the electrochromic medium and vary the variable luminous transmittance of the electrochromic medium.

Claims

1. An electrochromic aircraft window assembly comprising:

a) an outboard pane assembly; and

b) a fog preventing electrochromic pane assembly spaced from said outboard pane assembly and defining a chamber therebetween, said fog preventing electrochromic pane assembly comprising;

i) a first substrate having a first surface including a first conductive coating and a second surface including a second conductive coating;

ii) a second substrate spaced from said first substrate, said second substrate having a first surface including a third conductive coating, said second surface of said first substrate and said first surface of said second substrate facing each other in spaced-apart relation to define a chamber therebetween;

iii) an electrochromic medium contained in said chamber and in contact with said second and said third conductive coatings, said electrochromic medium having a luminous transmittance that varies upon application of an electrical potential through said electrochromic medium;

iv) facilities for applying electrical current to said first conductive coating to heat said first conductive coating, thereby preventing fogging of said window assembly; and

v) facilities for applying electrical current_to said second and said third conductive coatings to establish said electrical potential through said electrochromic medium and vary said variable luminous transmittance of said electrochromic medium.

2. The window assembly according to claim 1, wherein said outboard pane assembly and said fog preventing electrochromic pane assembly are contoured.

3. The window assembly according to claim 1, wherein said electrical current is applied to said first conductive coating at a power density ranging from 0.25 to 0.40 watts/in² to prevent fogging, and said electrical current is applied to said second and said third conductive coatings at a power density ranging from 0.0001 to 0.01 watts/in² to vary said luminous transmittance of said electrochromic medium.

4. The window assembly according to claim 1, wherein said electrical current is applied to said first conductive coating at a power density ranging from 0.25 to 0.40 watts/in² to prevent fogging.

5. The window assembly according to claim 1, wherein said electrical current is applied to said second and said third conductive coatings at a power density ranging from 0.0001 to 0.01 watts/in² to vary said luminous transmittance of said electrochromic medium.

6. The window assembly according to claim 1, wherein said electrochromic medium comprises at least one anodic electrochromic compound and at least one cathodic electrochromic compound, and wherein application of electrical potential to said electrochromic medium causes simultaneous oxidation of said anodic electrochromic compound and reduction of said cathodic electrochromic compound, thereby reducing said luminous transmittance.

7. The window assembly according to claim 6 wherein, said electrochromic medium is self-erasing upon elimination or reduction of electrical potential to said electrochromic medium.

8. The window assembly according to claim 1, wherein said luminous transmittance of said fog preventing electrochromic pane assembly of said window assembly varies from a minimum LTA ranging from 1 to 20 percent and a maximum LTA ranging from 60 to 80 percent.

9. The window assembly according to claim 1, wherein said first and second spaced substrates are glass.

10. The window assembly according to claim 1, wherein said outboard pane assembly comprises a laminated pane comprising an inboard acrylic layer, an outboard acrylic layer and an interlayer interposed between and adhering together said inboard acrylic layer and said outboard acrylic layer.

11. The window assembly according to claim 10, wherein said inboard acrylic layer is stretched acrylic ranging from 0.2 to 0.4 inches thick, said outboard acrylic layer is stretched acrylic ranging from 0.2 to 0.4 inches thick, and said interlayer is polyvinyl butyral ranging from 0.025 to 0.05 inches thick.

12. The window assembly according to claim 1, wherein said first substrate further comprises an adhesive interlayer deposited along at least a portion of said first surface of said first substrate, and a sound dampening material layer deposited over said adhesive interlayer.

13. The window assembly according to claim 12, wherein said sound dampening material layer is a laminate comprising a polyvinyl butyral layer and a polyester disposed over and in contact with said polyvinyl butyral layer.

14. The window assembly according to claim 12, wherein said first conductive coating is interposed between said adhesive layer and said base layer of said first substrate.