Windows with electrically controllable transmission and reflection

• US 20060274218A1
• Filed: 03/15/2006
• Published: 12/07/2006
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Serious Energy, Inc.
• Original Assignee: Serious Materials Incorporated
• Inventors: Xue, Jiuzhi
• Granted Patent: US 7,525,604 B2
• Time in Patent Office: Days
• US Class Current: 349/16
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133548 Wire-grid polarisers

Abstract

A window having electrically controllable transmission and reflection includes a layer of liquid crystal material and polarizers on either side thereof. Different combinations of absorptive and reflective polarizers are disclosed. These different combinations can be used in different applications to achieve the desired results. Transparent, conductive layers are provided to apply an electrical field to the liquid crystal material so as to selectively control the rotation of the polarization of light passing therethrough.

Claims

1. A glazing structure, comprising:

a first layer transmissive to light;

a second layer transmissive to light;

a layer of electrically controllable optically active material disposed between the first layer and the second layer;

a first polarization layer disposed to one side of the optically active layer that transmits light of a first polarization orientation and reflects light of the second polarization orientation; and

a second polarization layer disposed to an opposite side of the optically active layer that transmits light of one polarization orientation and absorbs light of another polarization orientation;

wherein the optically active layer can be controlled to either pass light without affecting the polarization or to pass light while rotating the polarization thereof; and

wherein the glazing structure is transmissive to light when the optically active layer passes light without affecting the polarization and the glazing structure reflects a substantial portion of the light that first enters the glazing structure from the opposite side when the optically active layer passes light while rotating the polarization thereof.

2. A glazing structure as defined in claim 1, wherein the optically active layer includes nematic liquid crystal material.

3. A glazing structure as defined in claim 1, wherein the optically active layer can be controlled to rotate the polarization orthogonally.

4. A glazing structure as defined in claim 1, wherein the glazing structure further includes a pair of layers of indium-tin-oxide (ITO) acting as electrodes to allow an electric field to be applied to the optically active layer.

5. A glazing structure as defined in claim 4, wherein at least one of the electrode layers is divided into a plurality of separate segments to allow different electric fields to be applied to different portions of the optically active layer.

6. A glazing structure as defined in claim 1, wherein the first and second transmissive layers include glass.

7. A glazing structure as defined in claim 1, wherein the first polarization layer is a reflective polarizer.

8. A glazing structure as defined in claim 7, wherein the second polarization layer is an absorptive polarizer.

9. A glazing structure as defined in claim 7, wherein the second polarization layer is a reflective polarizer.

10. A glazing structure as defined in claim 7, wherein the second polarization layer includes an absorptive polarizer and a reflective polarizer.

11. A glazing structure as defined in claim 1, wherein the first polarization layer is an absorptive polarizer.

12. A glazing structure as defined in claim 11, wherein the second polarization layer is an absorptive polarizer.

13. A glazing structure as defined in claim 11, wherein the second polarization layer is a reflective polarizer.

14. A glazing structure as defined in claim 11, wherein the second polarization layer includes an absorptive polarizer and a reflective polarizer.

15. A glazing structure as defined in claim 1, wherein the first polarization layer and the second polarization layer are each linear polarizers.

16. A glazing structure, comprising:

a substrate; and

means associated with the substrate for selectably controlling the amount of light transmitted through the glazing structure and the amount of light reflected by the glazing structure, the means including at least one reflective linear polarizer and at least one absorptive linear polarizer;

wherein the means controls the transmission and reflection of light at wavelengths across the entire visible and infrared light spectrum; and

wherein the means controls the amount of transmission and reflection with the selective application of electrical signals and without movement of mechanical components.

17. A method for controlling the amount of light transmitted through and reflected by a glazing structure, the method comprising:

providing a substrate with multiple layers applied thereto, wherein the multiple layers include an optically active layer, a reflective linear polarizer layer, and an absorptive linear polarizer layer; and

applying an electrical signal to at least one of the layers to change the amount of light transmitted through the glazing structure, wherein the transmission of light at wavelengths across the entire visible and infrared light spectrum is changed.

18. A method as defined in claim 17, wherein applying the electrical signal also changes the amount of light reflected by the glazing structure.

20. A glazing structure as defined in claim 18, wherein the first polarization layer is a reflective polarizer.

24. A glazing structure as defined in claim 18, wherein at least one of the electrically conductive layers is divided into a plurality of separate segments to allow different electric fields to be applied to different portions of the optically active layer.

19. A glazing structure, comprising:

a first glass layer;

a second glass layer;

a layer of liquid crystal material disposed between the first layer and the second layer;

a first polarization layer disposed to one side of the liquid crystal layer that transmits light of a first polarization orientation and reflects light of the second polarization orientation;

a second polarization layer disposed to an opposite side of the liquid crystal layer that transmits light of one polarization orientation and absorbs light of another polarization orientation; and

a pair of transparent, electrically conductive layers disposed on opposite sides of the liquid crystal layer;

wherein the liquid crystal layer can be controlled by selective application of electrical signals to the transparent conductive layers to either pass light without affecting the polarization or to pass light while rotating the polarization thereof; and

wherein the glazing structure is transmissive to light when the liquid crystal layer passes light without affecting the polarization and the glazing structure reflects a substantial portion of the light that first enters the glazing structure from the opposite side when the liquid crystal layer passes light while rotating the polarization thereof.

21. A glazing structure as defined in claim 19, wherein the second polarization layer is an absorptive polarizer.

22. A glazing structure as defined in claim 19, wherein the second polarization layer is a reflective polarizer.

23. A glazing structure as defined in claim 19, wherein the second polarization layer includes an absorptive polarizer and a reflective polarizer.