Light scattering coating for greenhouse applications, and/or coated article including the same

• US 20120251773A1
• Filed: 04/01/2011
• Published: 10/04/2012
• Est. Priority Date: 04/01/2011
• Status: Active Grant

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Krasnov, Alexey, Den Boer, Willem, Thomsen, Scott V., Lemmer, Jean-Marc
• Granted Patent: US 9,499,436 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: A01G 9/14 Greenhouses cloches A01G13/04
• CPC Class Codes: A01G 9/1438 Covering materials therefor; Materials for protective coverings used for soil and plants, e.g. films, canopies, tunnels or cloches
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2218/32 After-treatment
• CPC Class Codes: F24S 50/80 for controlling collection or absorption of solar radiation
• CPC Class Codes: F24S 80/52 characterised by the material for preventing heat loss F24S80/56
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: Y02A 40/25 Greenhouse technology, e.g. cooling systems therefor
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

Certain example embodiments relate to a sunlight-scattering thin-film coating disposed on a substrate for greenhouse applications. The surface morphology of the coating promotes a better and more uniform light distribution. For instance, at least one thin-film layer disposed on a substrate may be textured so as to create surface features on the order of 0.1-5 microns, with the surface features being sized to cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate. This arrangement may advantageously direct beneficial light towards plant life while directing parasitic light away from the plant life.

Claims

1. A coated article, comprising:

a coating supported by a substrate,

wherein the coating includes at least one thin-film layer that is textured so as to have surface features on the order of 0.3-3 microns that cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.

2. The coated article of claim 1, wherein the at least one thin-film layer has a refractive index (n) of 1.8-2.2 (at 550 nm).

3. The coated article of claim 1, wherein the at least one thin-film layer has a refractive index (n) of 1.9-2.1 (at 550 nm).

4. The coated article of claim 1, wherein the at least one thin-film layer is crystalline.

5. The coated article of claim 1, wherein the at least one thin-film layer comprises zinc oxide and/or tin oxide.

6. The coated article of claim 5, wherein the at least one thin-film layer is not doped.

7. The coated article of claim 5, wherein the at least one thin-film layer is 200-1,000 nm thick.

8. The coated article of claim 5, wherein the at least one thin-film layer is 300-500 nm thick.

9. The coated article of claim 8, wherein the coated article has a total solar transmission of at least about 85%.

10. The coated article of claim 8, wherein the coated article has a total solar transmission of at least about 90%.

11. A coated article, comprising:

a coating supported by a substrate,

wherein the coating includes at least one crystalline or polycrystalline thin-film layer that is textured so as to have micron- and/or sub-micron surface features that cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.

12. A method of making a greenhouse window, the method comprising:

disposing a coating including at least one thin-film layer on a substrate; and

texturing the at least one thin-film layer so as to create surface features on the order of 0.3-3 microns, the surface features being sized to cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.

13. The method of claim 12, wherein the at least one thin-film layer has a refractive index (n) of 1.8-2.2 (at 550 nm).

14. The method of claim 12, wherein the at least one thin-film layer comprises zinc oxide and/or tin oxide.

15. The method of claim 14, wherein the at least one thin-film layer is 300-500 nm thick.

16. The method of claim 12, wherein the coated article has a total solar transmission of at least about 90%.

17. The method of claim 12, wherein the at least one thin-film layer is pyrolytically deposited.

18. The method of claim 17, wherein process conditions of the pyrolytic deposition are selected and implemented so as to cause natural texturing of the at least one thin-film layer.

19. The method of claim 12, wherein the texturing includes chemical etching.

20. The method of claim 19, wherein the chemical etching is performed in connection with a weak acid etchant.

21. The method of claim 20, wherein the weak acid etchant includes multiple agents, the agents being selected to create features with different respective sizes within the 0.3-3 micron range.

22. The method of claim 12, wherein the texturing is performed via mechanical means.

23. The method of claim 12, wherein the at least one thin-film layer is sputter-deposited.

24. The method of claim 12, wherein the substrate is a glass substrate.

25. The method of claim 12, wherein an antireflective coating is disposed between the substrate and the at least one thin-film layer.