WINDOWS WITH ELECTRICALLY CONTROLLABLE TRANSMISSION AND REFLECTION

• US 20090284670A1
• Filed: 04/27/2009
• Published: 11/19/2009
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Serious Energy, Inc.
• Original Assignee: Serious Energy, Inc.
• Inventors: Xue, Jiuzhi
• Granted Patent: US 8,102,478 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 substrate;

a second substrate;

a layer of electrically controllable optically active material positioned between the first substrate and the second substrate, wherein the electrically controllable optically active material has a light transmissive state and a light reflective state;

at least one absorptive polarization layer disposed on a first surface of the optically active material layer;

at least one reflective polarization layer disposed on a second surface of the optically active material layer;

wherein the glazing structure is transmissive and substantially non-reflective of light when the optically active material is in the light transmissive state; and

wherein the glazing structure is substantially reflective of light when the optically active material is in the light reflective state.

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

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

4. A glazing structure as defined in claim 1, wherein the glazing structure further includes a pair of transparent electrically conductive layers disposed on the first and second substrates, the transparent electrically conductive layers acting as electrodes to allow an electric field to be applied to the optically active layer;

wherein the externally controllable optically active material can be controlled by the selective application of electrical signals to the transparent electrically conductive layers to be placed into the light transmissive state and the light reflective state.

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 substrates include glass.

7. A glazing structure as defined in claim 1, wherein the first and second substrates include transparent plastic films.

8. A glazing structure as defined in claim 1, wherein at least one absorptive polarization layer includes a circular polarizer that absorbs light having one of left and right circular polarization and transmits light having the other of left and right polarization.

9. A glazing structure as defined in claim 1, wherein at least one absorptive polarization layer and at least one reflective polarization layer includes a circular polarizer.

10. A glazing structure as defined in claim 1, wherein the glazing structure is part of a window of a building, and wherein the second surface of the optically active material layer faces the exterior of the building.

11. A glazing structure as defined in claim 1, wherein at least one absorptive polarization layer and at least one reflective polarization layer includes a linear polarizer.

12. A glazing structure, comprising:

a pair of glass substrates;

a pair of absorptive polarization layers positioned in between the pair of glass substrates;

a pair of reflective polarization layers having inner facing surfaces positioned in between the pair of absorptive polarization layers; and

a layer of electrically controllable optically active material in contact with the inner facing surfaces of the pair of reflective polarization layers, wherein the electrically controllable optically active material has two states;

(i) a light transmissive state whereby the glazing structure is transmissive and substantially non-reflective of light; and

(ii) a light reflective state whereby the glazing structure is substantially reflective of light.

13. A glazing structure as defined in claim 12, wherein the optically active material layer includes liquid crystals, and wherein the liquid crystals include nematic liquid crystal material.

14. A glazing structure as defined in claim 12, wherein the optically active material layer can be controlled to rotate the polarization of light orthogonally.

15. A glazing structure as defined in claim 12, wherein the glazing structure further includes a pair of layers of transparent electrically conductive layers disposed on the pair of glass substrates, the transparent electrically conductive layers acting as electrodes to allow an electric field to be applied to the optically active layer;

wherein the externally controllable optically active material can be controlled by the selective application of electrical signals to the transparent electrically conductive layers to be placed into the light transmissive state and the light reflective state.

16. A glazing structure as defined in claim 15, 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.

17. A glazing structure as defined in claim 12, wherein the pair of absorptive polarization layers includes a circular polarizer that absorbs light having one of left and right circular polarization and transmits light having the other of left and right polarization.

18. A glazing structure as defined in claim 12, wherein the pair of absorptive polarization layers and the pair of reflective polarization layers includes a circular polarizer.

19. A glazing structure as defined in claim 12, wherein the pair of absorptive polarization layers and the pair of reflective polarization layers includes a linear polarizer.

20. 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 to place the glazing structure into a plurality of optical states, the means including at least one reflective polarizer and at least one absorptive polarizer;

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

wherein the means controls the amount of transmission and reflection with the selective application of electrical signals and without movement of mechanical components, and wherein the selective application of electrical signals is operable to make the glazing structure transmissive and substantially non-reflective of light in at least one of the plurality of optical states.

21. A glazing structure as defined in claim 20, wherein the selective application of electric signals is applied to a nematic liquid crystal material.

22. A glazing structure as defined in claim 20, wherein the means includes a circular polarizer.

23. A glazing structure as defined in claim 20, wherein the means includes a linear polarizer.

24. 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 to place the glazing structure into a plurality of optical states, the means including at least one reflective polarizer and at least one absorptive polarizer;

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

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

wherein the means controls the amount of transmission and reflection with the selective application of electrical signals and without movement of mechanical components, and wherein the selective application of electrical signals is operable to make the glazing structure transmissive and substantially non-reflective of light in at least one of the plurality of optical states.