Thermal control of variable transmittance windows

• US 10,247,996 B2
• Filed: 06/22/2017
• Issued: 04/02/2019
• Est. Priority Date: 06/22/2016
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Driscoll, David I., Busscher, Bradley L., Stephenson, Michael T., Ash, Kevin L., Tonar, William L.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US15/630,100
• Publication Number:
  US 20170371222A1
• Time in Patent Office: 649 Days
• Field of Search: 359237-239, 359245, 359249, 359265, 359275-279, 359288, 359289, 324 96, 324 98, 324105, 2502011, 2502034, 700 19, 700 20, 700 22, 700 23, 700 25, 345105, 345106
• CPC Class Codes: B60J 3/04 adjustable in transparency
• CPC Class Codes: B60R 16/023 for transmission of signals between vehicle parts or subsystems
• CPC Class Codes: B61D 25/00 Window arrangements peculiar to rail vehicles vehicle window arrangements in general B60J; cleaning vehicle windows B60S; heating arrangements specially adapted for transparent or reflecting areas H05B3/84
• CPC Class Codes: E06B 2009/2417 Light path control; means to control reflection
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: E06B 2009/247 Electrically powered illumination
• CPC Class Codes: E06B 3/6722 with adjustable passage of light
• 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: G01R 21/02 by thermal methods , e.g. calorimetric
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G01R 31/002 where the device under test is an electronic circuit
• 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
• CPC Class Codes: G02F 2203/48 Variable attenuator
• CPC Class Codes: Y02T 30/00 Transportation of goods or passengers via railways, e.g. energy recovery or reducing air resistance

Abstract

An electrical control system for controlling a variable transmittance window is disclosed. The system comprises a driver circuit in communication with an electro-optic element. A controller is in communication with the driver circuit. The controller is configured to identify a temperature condition of the electro-optic element and adjust an output voltage supplied to the electro-optic element in response to the temperature condition.

Claims

1. A variable transmittance window system, comprising:

an electro-optic element disposed in a window assembly;

a driver circuit in communication with the electro-optic element;

a current sensor configured to identify a current draw of the driver circuit; and

a controller in communication with the driver circuit and the current sensor, wherein the controller is configured to;

identify a temperature of the electro-optic element based on the current draw;

compare the temperature to a temperature threshold; and

increase a transmittance of the electro-optic element in response to the temperature exceeding the temperature threshold.

2. The window system according to claim 1, wherein the controller is configured to increase the transmittance by limiting an output voltage supplied to the electro-optic element.

3. The window system according to claim 1, further comprising a photo sensor disposed proximate to the electro-optic element.

4. The window system according to claim 3, wherein the controller is further configured to:

identify a transmittance level of the electro-optic element based on a transmittance signal received from the photo sensor.

5. The window system according to claim 4, wherein the controller is further configured to:

identify the temperature based on the current draw of the electro-optic element and the transmittance signal.

6. The window system according to claim 4, wherein the controller is further configured to:

identify a condition of the temperature based on a correlation of the current draw to a transmittance level of the electro-optic element identified from the transmittance signal.

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

a driver circuit in communication with an electro-optic element; and

a controller in communication with the driver circuit, wherein the controller is configured to;

identify a temperature condition of the electro-optic element;

adjust an output voltage supplied to the electro-optic element in response to the temperature condition; and

adjust the output voltage increasing a transmittance of the electro-optic element in response to the temperature condition indicating that a temperature threshold is exceeded.

8. The control system according to claim 7, wherein the controller comprises a current sensor configured to identify a current draw of the electro-optic element.

9. The control system according to claim 8, wherein the controller is further configured to:

identify the temperature condition in response to the current draw by the electro-optic element.

10. The control system according to claim 8, further comprising a photo sensor disposed proximate to the electro-optic element.

11. The control system according to claim 10, wherein the controller is further configured to:

identify a transmittance level of the electro-optic element based on a transmittance signal received from the photo sensor.

12. The control system according to claim 11, wherein the controller is further configured to:

identify the temperature condition based on the current draw of the electro-optic element and the transmittance signal.

13. The control system according to claim 11, wherein the controller is further configured to:

identify the temperature condition based on a correlation of the current draw to a transmittance level of the electro-optic element identified from the transmittance signal.

14. The control system according to claim 7, further comprising a temperature sensor disposed proximate the electro-optic element.

15. The control system according to claim 14, wherein the controller is further operable to:

identify the temperature condition of the electro-optic element based on a temperature signal from the temperature sensor.

16. A variable transmittance window system, comprising:

an electro-optic element disposed in a window assembly;

a driver circuit in communication with the electro-optic element;

at least one sensor configured to identify a property of the electro-optic element; and

a controller in communication with the driver circuit and the at least one sensor, wherein the controller is configured to;

identify a temperature of the electro-optic element based on the property of the electro-optic element;

compare the temperature to a temperature threshold; and

increase a transmittance of the electro-optic element in response to the temperature exceeding the temperature threshold.

17. The window system according to claim 16, wherein the sensor comprises at least one of a current sensor, a temperature sensor, and a photo sensor.

18. The window system according to claim 16, wherein the sensor comprises a current sensor configured to identify a current draw of the driver circuit.

19. The window system according to claim 18, wherein the controller is further configured to:

identify the temperature of the electro-optic element based on a correlation of the current draw to a temperature of the electro-optic element.