Thermally switched optical downconverting filter

• US 8,076,661 B2
• Filed: 07/26/2010
• Issued: 12/13/2011
• Est. Priority Date: 01/24/2007
• Status: Active Grant

• Current Assignee: Ravenbrick, LLC
• Original Assignee: Ravenbrick, LLC
• Inventors: McCarthy, Wil, Powers, Richard M.
• Primary Examiner(s): Petkovsek, Daniel
• Application Number:
  US12/843,218
• Publication Number:
  US 20100288947A1
• Time in Patent Office: 505 Days
• Field of Search: 359326-332, 359/359, 359/641, 359/707, 359/885, 349/104, 250/517.1
• US Class Current: 250/517.1
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 2217/218 V2O5, Nb2O5, Ta2O5
• CPC Class Codes: C03C 2217/219 CrOx, MoOx, WOx
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: G02B 5/0289 used as a transflector
• CPC Class Codes: G02B 5/223 containing organic substances, e.g. dyes, inks or pigments
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 2/02 Frequency-changing of light, e.g. by quantum counters

Abstract

A thermally switched optical downconverting (TSOD) filter is a self-regulating device including a downconverter that converts incoming light at a variety of wavelengths into longer-wavelength radiation and then directs it using one or more bandblock filters in either the inward or outward direction, depending on the temperature of the device. This control over the flow of radiant energy occurs independently of the thermal conductivity or insulating properties of the device and may or may not preserve the image and color properties of incoming visible light. The TSOD filter is energy-efficient as it can be used to regulate the internal temperature and illumination of buildings, vehicles, and other structures without the need for an external power supply or operator signals. The TSOD filter has unique aesthetic and optical properties not found in traditional windows, skylights, stained glass, light fixtures, glass blocks, bricks, or walls.

Claims

1. A window comprising

a first pane of glass;

a first low emissivity coating on a surface of the first glass pane;

a thermochromic downconverter film supported by the first glass pane, wherein

the thermochromic downconverter film absorbs incident light of a broad bandwidth and emits light at an emission wavelength substantially or entirely longer than wavelengths of the broad bandwidth, and

the emission wavelength is variable depending upon a temperature of the downconverter layer; and

the first low emissivity coating blocks the emitted light when a temperature of the window is in a first range and passes the emitted light when the temperature of the window is in a second range.

2. The window of claim 1 further comprising a second low emissivity coating on the thermochromic downconverter film on an opposite side of the thermochromic downconverter film than the first low emissivity coating.

3. The window of claim 1 further comprising

a second low emissivity coating on the thermochromic downconverter film on an opposite side of the thermochromic downconverter film than the first low emissivity coating;

a second pane of glass spaced apart from the thermochromic downconverter film; and

a transparent insulating layer sandwiched between the second glass pane and the thermochromic downconverter film.

4. The window of claim 3, wherein the transparent insulating layer is an air gap.

5. The window of claim 3, wherein

the first low emissivity coating blocks the emitted light when the temperature of the thermochromic downconverter film is below a first threshold temperature and passes the emitted light when the temperature of the thermochromic downconverter film is above a second threshold temperature;

and

the second low emissivity coating passes the emitted light when the temperature of the thermochromic downconverter film is below the first threshold temperature and blocks the emitted light when the temperature of the thermochromic downconverter film is above the second threshold temperature.

6. The window of claim 1 further comprising

a second pane of glass spaced apart from the thermochromic downconverter layer;

a second low emissivity coating on the second glass pane; and

a transparent insulating layer sandwiched between the second glass pane and the first low emissivity coating.

7. The window of claim 6, wherein the transparent insulating layer is an air gap.

8. The window of claim 6, wherein

the first low emissivity coating blocks the emitted light when the temperature of the thermochromic downconverter film is below a first threshold temperature and passes the emitted light when the temperature of the thermochromic downconverter film is above a second threshold temperature;

and

the second low emissivity coating passes the emitted light when the temperature of the thermochromic downconverter film is below the first threshold temperature and blocks the emitted light when the temperature of the thermochromic downconverter film is above the second threshold temperature.

9. The window of claim 1 further comprising a thermochromic attenuator supported by the first glass pane.

10. The window of claim 9, wherein the thermochromic attenuator is positioned between the first glass pane and the first low emissivity coating whereby the first low emissivity coating covers a surface of the thermochromic attenuator instead of the surface of the first glass pane.

11. The window of claim 9, wherein the thermochromic attenuator comprises a liquid crystal plate.

12. The window of claim 9, wherein the thermochromic attenuator comprises a film of a thermochromic, optically reflective material.

13. The window of claim 9, wherein the thermochromic attenuator comprises a film of a thermochromic, infrared reflective material.

14. The window of claim 1, wherein the thermochromic downconverter film defines a plurality of transparent openings.

15. A method for regulating the flow of light and radiant heat comprising

absorbing incident light at multiple wavelengths with a downconverter;

emitting the incident light from the downconverter at an emission wavelength substantially or entirely longer than the wavelengths of the incident light; and

reflecting the emitted light with one or more bandblock filters, wherein

the emitted light escapes in an inward direction when an ambient temperature is in a first range;

the emitted light escapes in an outward direction when the ambient temperature is in a second range; and

the emitted light escapes in both the inward direction and the outward direction when the ambient temperature is between the first range and the second range.

16. The method of claim 15 further comprising passively and selectively passing and blocking the incident light with a thermochromic attenuator based upon the ambient temperature.

17. A method for regulating the temperature of a building comprising

cladding an exterior surface of at least a portion of the building with a layered material comprising a downconverter layer and one or more bandblock filters;

absorbing incident light at multiple wavelengths within the downconverter layer;

emitting the incident light from the downconverter layer at an infrared wavelength; and

reflecting the emitted light with one or more bandblock filters, wherein

the emitted light escapes in an inward direction when an ambient temperature is below a first threshold temperature;

the emitted light escapes in an outward direction when the ambient temperature is above a second threshold temperature; and

the emitted light escapes in both the inward direction and the outward direction when the ambient temperature is between the first threshold temperature and the second threshold temperature.

18. The method of claim 17, wherein the cladding further comprises a thermochromic attenuator layer and the method further comprises passively and selectively passing and blocking the incident light with the thermochromic attenuator layer based upon the ambient temperature.