Enhanced thermochromic window which incorporates a film with multiple layers of alternating refractive index

• US 9,128,307 B2
• Filed: 02/20/2013
• Issued: 09/08/2015
• Est. Priority Date: 02/20/2012
• Status: Active Grant

• Current Assignee: Pleotint LLC
• Original Assignee: Pleotint LLC
• Inventors: Broekhuis, Michael D., Byker, Harlan J., Millett, Frederick A.
• Primary Examiner(s): Allen, Stephone B
• Assistant Examiner(s): THOMAS, BRANDI N
• Application Number:
  US13/771,285
• Publication Number:
  US 20130229702A1
• Time in Patent Office: 930 Days
• Field of Search: 359/288, 359290-292, 359/301, 3592011-2031, 359/207.11, 359/209.1, 359/210.1, 359/212.1, 359275-277
• US Class Current: 1/1
• CPC Class Codes: B32B 17/10005 laminated safety glass or glazing
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10477 thermochromic
• CPC Class Codes: B32B 17/10651 comprising colorants, e.g. dyes or pigments
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B32B 2333/12 Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate
• CPC Class Codes: G02F 1/0063 Optical properties, e.g. absorption, reflection or birefringence materials for non-linear optics G02F1/355
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence

Abstract

A window comprising at least one thermochromic layer and a film comprising multiple layers of polymer with alternating refractive index (MLARI). The thermochromic layer has a reversible change in absorbance of electromagnetic radiation such that the absorbance increases as the temperature of the thermochromic layer increases and the absorbance decreases as the temperature of the thermochromic layer decreases. Particularly useful thermochromic materials are ligand exchange thermochromic materials. In various embodiments, the window may have multiple panes and may incorporate a low-e layer.

Claims

1. A window comprising more than one thermochromic layer wherein two of the thermochromic layers are separated by a film comprising multiple layers of polymer with alternating refractive index (MLARI) wherein the thermochromic layers each have a reversible change in absorbance of electromagnetic radiation such that the absorbance increases as the temperature of the thermochromic layer increases and the absorbance decreases as the temperature of the thermochromic layer decreases, and wherein the MLARI film reflects near infrared radiation.

2. The window of claim 1 wherein each thermochromic layer contains a ligand exchange thermochromic system.

3. The window of claim 1 wherein at least one of the thermochromic layers is adhered to the MLARI film.

4. The window of claim 3 wherein the MLARI film is treated to promote adhesion.

5. The window of claim 3 wherein the thermochromic layers and the MLARI film are laminated between rigid substrates of glass or plastic.

15. The window of claim 1 wherein the window has a face facing the sun and comprises in order as defined from the face of the window facing the sun:

a glass or plastic substrate, a first thermochromic layer, a MLARI film, a second thermochromic layer, and a second glass or plastic substrate.

16. The window of claim 1 wherein the window is a double pane window and has a face facing the sun and the pane on the face of the window facing the sun comprises in order as defined from the face of the window facing the sun:

a glass or plastic substrate, a first thermochromic layer, a MLARI film, a second thermochromic layer, and a second glass or plastic substrate.

17. The window of claim 1 wherein the MLARI film comprises alternating layers of two of the following polymers:

a cyclohexanedimethanol modified polyester terephthalate, a copolymer of cyclohexanedimethanol modified polyester terephthalate, polymethylmethacrylate, polycarbonate, polyethylene naphthalate, polyethylene terephthalate, polyethylene and polystyrene.

18. The window of claim 17 wherein the MLARI film comprises alternating layers of polymethylmethacrylate and polycarbonate.

19. The window of claim 17 wherein the MLARI film comprises alternating layers of polymethylmethacrylate and a birefringent polyester.

20. The window of claim 17 wherein the MLARI film comprises alternating layers of polymethylmethacrylate and a birefringent polyethylene naphthalate or polyethylene terephthalate.

21. The window of claim 17 wherein the MLARI film comprises alternating layers of polyethylene and polystyrene.

22. The window of claim 3 wherein both of the thermochromic layers separated by MLARI film are adhered to the MLARI film.

6. A window comprising more than one thermochromic layer wherein two of the thermochromic layers are adhered to and separated by a film comprised of multiple layers of polymer with alternating refractive index (MLARI) wherein the thermochromic layers each have a reversible change in absorbance of electromagnetic radiation such that the absorbance increases as the temperature of the thermochromic layer increases and the absorbance decreases as the temperature of the thermochromic layer decreases, and wherein the MLARI film reflects near infrared radiation.

7. The window of claim 6 wherein the thermochromic layer contains a ligand exchange thermochromic system.

8. The window of claim 6 wherein the MLARI film is treated to promote adhesion.

9. The window of claim 6 wherein the thermochromic layer and the MLARI film are laminated between rigid substrates of glass or plastic.

10. A window which comprises:

a) first and second thermochromic layers;

b) a film comprised of multiple layers of polymer with alternating refractive index (MLARI), wherein the MLARI film reflects near infrared radiation;

c) a pair of rigid substrates;

d) a hard coat low-e coating on at least one of the substrates;

wherein the first and second thermochromic layers each have a reversible change in absorbance of electromagnetic radiation such that the absorbance increases as the temperature of the thermochromic layer increases and the absorbance decreases as the temperature of the thermochromic layer decreases, wherein the MLARI film is positioned between the first and the second thermochromic lavers, and wherein the thermochromic layers and the MLARI film are laminated between the rigid substrates;

wherein the window is a single pane or monolithic window.

11. The window of claim 10 wherein each thermochromic layer contains a ligand exchange thermochromic system.

12. The window of claim 10 wherein at least one of the first and second thermochromic layers is adhered to the MLARI film.

13. The window of claim 12 wherein the MLARI film is treated to promote adhesion.

14. The window of claim 10 wherein the hard coat low-e coating is on the exterior of one of the substrates.