WINDOW TREATMENT CONTROL USING BRIGHT OVERRIDE

• US 20160047164A1
• Filed: 08/14/2014
• Published: 02/18/2016
• Est. Priority Date: 08/14/2013
• Status: Active Grant

• Current Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Lundy, Stephen, Protzman, Brent, Courtney, Brian Michael
• Granted Patent: US 10,017,985 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: E06B 2009/6827 sensing light
• CPC Class Codes: E06B 9/68 Operating devices or mechanisms, e.g. with electric drive

Abstract

A system includes a window treatment adjacent to a window of a room. At least one motor drive unit is associated with the window treatment, for varying the position of the window treatment. A sensor measures a light level (e.g., an outdoor light level) at the window. A controller provides signals to the motor drive unit to automatically adjust the position of the window treatment so as to control a penetration distance of sunlight into the room when the window treatment is partially opened. The controller is configured to position the window treatment in a bright override position if the measured light level is at least a bright threshold value. The controller is configured to select the bright threshold value from among at least two predetermined values. The selection depends on an angle of incidence between light rays from the sun and a surface normal of the window.

Claims

1. A system comprising:

A motorized window treatment positioned adjacent to a window of a room, the motorized window treatment having a motor drive unit for adjusting a position of the window treatment;

a sensor for measuring a light level at the window;

a controller configured for providing signals to the motor drive unit to automatically adjust the position of the window treatment so as to control a penetration distance of sunlight into the room when the window treatment is partially opened, the controller configured to adjust the position of the window treatment to a bright override position if the measured light level is greater than or equal to a bright threshold value,

wherein the controller is configured to select the bright threshold value from among at least two predetermined values, the selection depending on an angle of incidence between light rays from the sun to the window and a surface normal line perpendicular to a surface of the window.

2. The system of claim 1, wherein the controller is configured to dynamically select the bright threshold value periodically during a day.

3. The system of claim 1, wherein the controller is configured to select the lower one of the at least two predetermined values if the angle of incidence is about 95 degrees or greater.

4. The system of claim 1, wherein the controller is configured to select the lower one of the at least two predetermined values if the angle of incidence is about 90 degrees or greater.

5. The system of claim 1, wherein:

if the current value of the bright threshold is the higher of the at least two predetermined values, the controller is configured to select the lower one of the at least two predetermined values if the angle of incidence is about 95 degrees or more.

6. The system of claim 1, wherein:

if the current value of the bright threshold is the lower of the at least two predetermined values, the controller is configured to select the higher one of the at least two predetermined values if the angle of incidence is about 85 degrees or less.

7. The system of claim 1, wherein the bright override position is a completely closed position or almost completely closed position.

8. The system of claim 1, wherein the controller is configured to adjust the position of the window treatment to a visor position, if:

the measured light level is less than the bright threshold value; and

the visor position is closer to a completely closed position than a current position calculated by the controller to control the penetration distance of sunlight into the room.

9. The system of claim 1, wherein the controller is configured to adjust the position of the window treatment to a dark override position if the measured light level is equal to or less than a dark threshold value.

10. The system of claim 9, wherein the window treatment is fully open or near fully open in the dark override position.

11. The system of claim 10, wherein the controller is configured to adjust the position of the window treatment to a visor position between the bright override position and the dark override position if:

the angle of incidence is at least 90 degrees, and the light level is greater than or equal to the lower two predetermined values, or

the angle of incidence is less than 90 degrees, and the visor position is more closed than a current position calculated to limit the penetration distance to a maximum penetration distance.

12. The system of claim 1, wherein:

the controller is a system controller,

the at least one motor drive unit comprises a plurality of motor drive units, each motor drive unit located along a respective faç

ade for controlling at least one respective window treatment,

the controller is configured for providing signals to each motor drive unit to automatically adjust a position of each window treatment coupled to that motor drive unit so as to control a penetration distance of sunlight into one or more rooms when the respective window treatment is partially opened, and

the controller is configured to control the adjust the position of each window treatment corresponding to each motor drive unit to a bright override position if a respective measured light level corresponding to a faç

ade having that motor drive unit is greater than or equal to a bright threshold value.

13. The system of claim 1, wherein the controller is included within a housing of the motor drive unit.

14. The system of claim 1, wherein the sensor has a housing, and the controller is contained within the housing of the sensor.

15. A system comprising:

a window treatment positioned adjacent to a window of a room, the motorized window treatment having a motor drive unit for adjusting a position of the window treatment;

a sensor for measuring a light level at the window;

a controller configured for providing signals to the motor drive unit to automatically adjust the position of the window treatment so as to control a penetration distance of sunlight into the room when the window treatment is partially opened, the controller configured to position the window treatment in a bright override position if the measured light level is greater than or equal to a bright threshold value,

wherein the controller is configured to dynamically determine the bright threshold value based on an altitude angle of the sun and an incident angle between rays from the sun and a surface normal of the window.

16. The system of claim 15, wherein the controller dynamically calculates the bright threshold value periodically during a day.

17. The system of claim 16, wherein the controller dynamically calculates the bright threshold value as a function of the altitude angle and the incident angle.

18. The system of claim 17, wherein the controller dynamically calculates the bright threshold value according to the equation:

Emax=(Esun/0.8)*Calt*Cinc,

where;

Emax is the bright threshold value;

Esun is a predetermined maximum bright threshold value;

Calt is a function of the altitude angle of the sun; and

Cinc is a function of the incident angle of the sun.

19. The system of claim 18, wherein Calt is given by the equation:

Calt=1−

0.75*[1−

exp(−

0.21/sin At)/0.81],

where At is the altitude angle of the sun.

20. The system of claim 19, wherein Cinc is given by the equation:

Cinc=[1−

cos Ai]*[1−

Eshade/Esun]

where Ai is the incident angle of the sun; and

Eshade is a predetermined minimum bright threshold value.

21. A controller,

the controller configured for providing signals to a motor drive unit to automatically adjust a position of a window treatment adjacent a window, so as to control a penetration distance of sunlight into a room when the window treatment is partially opened,

the controller configured to adjust the position of the window treatment to a bright override position if a measured light level is greater than or equal to a bright threshold value,

wherein the controller is configured to select the bright threshold value from among at least two predetermined values, the selection depending on an angle of incidence between light rays from the sun and a surface normal of the window.

22. The controller of claim 21, wherein the controller is configured to dynamically select the bright threshold value periodically during a day.

23. The controller of claim 21, wherein:

if the current value of the bright threshold is the higher of the at least two predetermined values, the controller is configured to select the lower one of the at least two predetermined values if the angle of incidence is about 95 degrees or more.

24. The controller of claim 21, wherein:

if the current value of the bright threshold is the lower of the at least two predetermined values, the controller is configured to select the higher one of the at least two predetermined values if the angle of incidence is about 85 degrees or less.

25. The controller of claim 21, wherein the controller is configured to adjust the position of the window treatment to a visor position, if:

the measured light level is less than the bright threshold value; and

the visor position is closer to a completely closed position than a current position calculated by the controller to control the penetration distance of sunlight into the room.

26. The controller of claim 21, wherein the controller is configured to position the window treatment in a dark override position if the measured light level is equal to or less than a dark threshold value.

27. The controller of claim 26, wherein the window treatment is fully open or near fully open in the dark override position.

28. The controller of claim 27, wherein the controller is configured to position the window treatment in a visor position between the bright override position and the dark override position if:

the angle of incidence is at least 90 degrees, and the light level is greater than or equal to the lower two predetermined values, or

the angle of incidence is less than 90 degrees, and the visor position is more closed than a current position calculated to limit the penetration distance.

29. A method, comprising

automatically providing signals to a motor drive unit to automatically adjust a position of a window treatment adjacent a window, so as to control a penetration distance of sunlight into a room when the window treatment is partially opened,

automatically adjusting the position of the window treatment to a bright override position if a measured light level is greater than or equal to a bright threshold value, and

automatically selecting the bright threshold value from among at least two predetermined values, the selection depending on an angle of incidence between light rays from the sun and a surface normal of the window.

30. The method of claim 29, wherein the selecting step includes selecting the bright threshold value periodically during a day.

31. The method of claim 29, wherein the selecting step includes selecting the lower one of the at least two predetermined values if:

the current value of the bright threshold is the higher of the at least two predetermined values, and

the angle of incidence is about 95 degrees or more.

32. The method of claim 29, wherein the selecting step includes selecting the higher one of the at least two predetermined values if:

the current value of the bright threshold is the lower of the at least two predetermined values, and

the controller is configured to the angle of incidence is about 85 degrees or less.

33. The method of claim 29, further comprising:

automatically calculating a current position to limit the penetration distance of sunlight into the room to a maximum penetration distance, and

automatically adjusting the position of the window treatment to a visor position, if;

the measured light level is less than the bright threshold value; and

the visor position is closer to a completely closed position than a current position calculated by the controller to control the penetration distance of sunlight into the room.

34. The method of claim 29, further comprising automatically adjusting the position of the window treatment to a dark override position if the measured light level is equal to or less than a dark threshold value.

35. The method of claim 34, wherein the window treatment is fully open or near fully open in the dark override position.

36. The method of claim 35, further comprising automatically adjusting the position of the window treatment to a visor position between the bright override position and the dark override position if:

the angle of incidence is at least 90 degrees, and the light level is greater than or equal to the lower two predetermined values, or

the angle of incidence is less than 90 degrees, and the visor position is more closed than a current position calculated to limit the penetration distance.

37. A non-transitory machine-readable storage medium encoded with program instructions, such that, when the program instructions are executed by a controller, the controller performs a method, comprising

automatically providing signals to a motor drive unit to automatically adjust a position of a window treatment adjacent a window, so as to control a penetration distance of sunlight into a room when the window treatment is partially opened,

automatically adjusting the position of the window treatment to a bright override position if a measured light level is greater than or equal to a bright threshold value, and

automatically selecting the bright threshold value from among at least two predetermined values, the selection depending on an angle of incidence between light rays from the sun and a surface normal of the window.