Thermally-responsive film

Patent metadata

Field	Value
Publication number	US-9506243-B1
Application number	US-201514664471-A
Country	US
Kind code	B1
Filing date	Mar 20, 2015
Priority date	Mar 20, 2014
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

The present invention relates to a thermally-responsive film that may, for example, be affixed to an exterior surface of a building to help control its temperature as it is exposed to the sun. The thermally-responsive film has a continuous phase and a discontinuous phase. The discontinuous phase comprises a plurality of droplets, each of which comprises the light-absorbing suspending fluid and the light-reflecting particles. The light-reflecting particles are dispersed in a vehicle that is either a second fluid that is immiscible with the suspending fluid and has a higher volumetric coefficient of thermal expansion than the suspending fluid, or a combination of materials that together have a higher volumetric coefficient of thermal expansion than the suspending fluid that together with the light-reflecting particles form composite particles. At temperatures lower than a threshold temperature, the vehicle containing the light-reflecting particles has a higher density than the suspending fluid and sinks towards the rear surface of the film, so that incident light is absorbed. At temperatures higher than the threshold temperature, the vehicle containing the light-reflecting particles has a lower density than the suspending fluid and moves towards the front surface of the film, enabling the light-reflecting particles to reflect incident light.

First claim

What is claimed is:

1. A thermally-responsive film comprising a continuous phase and a discontinuous phase, wherein the discontinuous phase comprises a plurality of droplets, each droplet comprising a light-absorbing suspending fluid and a vehicle containing light-reflecting particles, wherein the vehicle's density is temperature-dependent.

2. A film of claim 1 , wherein the vehicle is a liquid that is immiscible with the suspending fluid.

3. A film of claim 1 , wherein the vehicle is a composite particle.

4. A film of claim 3 , wherein the composite particle comprises density-altering components embedded in a polymer.

5. A film of claim 4 , wherein the density altering components are gas or foam.

6. A building having a least one external surface that is at least partially covered by a film of claim 1 .

7. A building according to claim 6 , wherein the external surface is a roof.

8. A building according to claim 6 , wherein the external surface is a side wall.

9. A film of claim 1 , wherein the film displays the color of the light-absorbing suspending fluid at low temperature but displays the color of the light-reflecting particles at high temperature.

10. The film of claim 1 , wherein the density of the vehicle is less than the density of the light-absorbing suspending fluid at a temperature hotter than 72° F. (22° C.

11. The film of claim 10 , wherein the density of the vehicle is less than the density of the light-absorbing suspending fluid at a temperature hotter than 80° F. (27° C.

12. The film of claim 1 , wherein the density of the vehicle at 72° F. (22° C.) and hotter is 700 kg/m 3 or less.

13. The film of claim 1 , wherein the absorption coefficient of the light-absorbing suspending fluid is 1/mm or greater.

Assignees

• E Ink Corp

Inventors

• Harris George G
• Sainis Sunil Krishna

Classifications

• G02F2001/1678

  characterised by the composition or particle type · CPC title

• E06B2009/2411

  Coloured fluid flow for light transmission control · CPC title

• E06B9/24

  Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; {Slat blinds}(operating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00) · CPC title

• G02F1/167

  by electrophoresis · CPC title

• E04B1/76 Primary

  specifically with respect to heat only (heat insulation in general F16L59/00) · CPC title