Omnidirectional structural color microstructures comprising titanium dioxide

Patent metadata

Field	Value
Publication number	US-2024053521-A1
Application number	US-202217886768-A
Country	US
Kind code	A1
Filing date	Aug 12, 2022
Priority date	Aug 12, 2022
Publication date	Feb 15, 2024
Grant date	—

Abstract

A multilayer thin film that reflects an omnidirectional structural color having a reflective core layer; an amorphous-phase TiO2 dielectric layer extending across the reflective core layer; a metallic absorbing layer extending across the dielectric layer; and a dielectric outer layer extending across the metallic absorbing layer. The multilayer thin film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, and a color shift of the single narrow band of visible light is less than 30° measured in Lab color space when the multilayer thin film is exposed to broadband electromagnetic radiation and viewed from angles between 0° and 45° relative to a direction normal to an outer surface of the multilayer thin film.

First claim

1 . A multilayer thin film that reflects an omnidirectional structural color comprising:
a reflective core layer; an amorphous-phase TiO 2 dielectric layer extending across the reflective core layer; a metallic absorbing layer extending across the amorphous-phase TiO 2 dielectric layer; and a dielectric outer layer extending across the metallic absorbing layer, wherein the multilayer thin film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising: a color shift of the single narrow band of visible light is less than 30° measured in Lab color space when the multilayer thin film is exposed to broadband electromagnetic radiation and viewed from angles between 0° and 45° relative to a direction normal to an outer surface of the multilayer thin film.

2 . The multilayer thin film of claim 1 , wherein the reflective core layer is formed from Al, Ag, Pt, Sn, Au, Cu, brass, bronze, TiN, Cr, or combinations thereof.

3 . The multilayer thin film of claim 1 , wherein the reflective core layer has a thickness between 50 nm and 500 nm.

4 . The multilayer thin film of claim 1 , wherein the amorphous-phase TiO 2 dielectric layer has a thickness between 10 nm and 150 nm.

5 . The multilayer thin film of claim 1 , wherein the metallic absorbing layer is formed from W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, or combinations thereof.

6 . The multilayer thin film of claim 1 , wherein the metallic absorbing layer has a thickness between 5 nm and 20 nm.

7 . The multilayer thin film of claim 1 , wherein the dielectric outer layer is formed from ZnS, TiO 2 , and combinations thereof.

8 . The multilayer thin film of claim 1 , wherein the dielectric outer layer has a thickness greater than 0.1 quarter wave (QW) to less than or equal to 4.0 QW where a control wavelength is determined by a target wavelength at a peak reflectance in a visible wavelength.

9 . The multilayer thin film of claim 1 , wherein the dielectric outer layer has a thickness between 5 nm and 500 nm.

10 . The multilayer thin film of claim 1 , wherein
the reflective core layer is formed from Al, the metallic absorbing layer is formed from W, and the dielectric outer layer is formed from ZnS or TiO 2 .

11 . A multilayer thin film that reflects an omnidirectional structural color comprising:
a reflective core layer; a protective layer encapsulating the reflective core layer;
an amorphous-phase TiO 2 dielectric layer extending across at least a portion of the protective layer;
a barrier layer extending across the amorphous-phase TiO 2 dielectric layer;
a metallic absorbing layer extending across the barrier layer; and
a dielectric outer layer extending across the metallic absorbing layer, wherein
the multilayer thin film reflects a single narrow band of visible light when exposed to broadband electromagnetic radiation, the single narrow band of visible light comprising:
a color shift of the single narrow band of visible light is less than 30° measured in Lab color space when the multilayer thin film is exposed to broadband electromagnetic radiation and viewed from angles between 0° and 45° relative to a direction normal to an outer surface of the multilayer thin film.

12 . The multilayer thin film of claim 11 , wherein the reflective core layer is formed from Al, Ag, Pt, Sn, Au, Cu, brass, bronze, TiN, Cr, or combinations thereof.

13 . The multilayer thin film of claim 11 , wherein the reflective core layer has a thickness between 50 nm and 500 nm.

14 . The multilayer thin film of claim 11 , wherein the protective layer is formed from SiO 2 , SnO 2 , Al 2 O 3 , or combinations thereof.

15 . The multilayer thin film of claim 11 , wherein the protective layer has a thickness between 2 nm and 70 nm.

16 . The multilayer thin film of claim 11 , wherein the amorphous-phase TiO 2 dielectric layer has a thickness between 10 nm and 150 nm.

17 . The multilayer thin film of claim 11 , wherein the metallic absorbing layer is formed from W, Cr, Ge, Ni, stainless steel, Pd, Ti, Si, V, TiN, Co, Mo, Nb, ferric oxide, amorphous silicon, or combinations thereof.

18 . The multilayer thin film of claim 11 , wherein the metallic absorbing layer has a thickness from 5 nm to 20 nm.

19 . The multilayer thin film of claim 11 , wherein the dielectric outer layer is formed from ZnS, TiO 2 , and combinations thereof.

20 . The multilayer thin film of claim 11 , wherein the dielectric outer layer has a thickness greater than 0.1 quarter wave (QW) to less than or equal to 4.0 QW where a control wavelength is determined by a target wavelength at a peak reflectance in a visible wavelength.

21 . The multilayer thin film of claim 11 , wherein the dielectric outer layer has a thickness between 5 nm and 500 nm.

22 . The multilayer thin film of claim 11 , wherein the barrier layer is formed from Al 2 θ 3 .

23 . The multilayer thin film of claim 11 , wherein the barrier layer has a thickness that is between 1 nm and 15 nm.

24 . The multilayer thin film of claim 11 , wherein
the reflective core layer is formed from Al, the protective layer is formed from SiO 2 , the metallic absorbing layer is formed from W, the barrier layer is made formed from Al 2 O 3 , and the dielectric outer layer is formed ZnS or TiO 2 .

25 . A method for forming the multilayer thin film of claim 1 , the method comprising:
depositing the amorphous-phase TiO 2 dielectric layer onto the reflective core layer by CVD or ALD; depositing the metallic absorbing layer onto the amorphous-phase TiO 2 dielectric layer by ALD; and depositing the dielectric outer layer onto the metallic absorbing layer by CVD or ALD.

26 . A method for forming the multilayer thin film of claim 11 , the method comprising:
depositing the protective layer onto the reflective core layer by wet chemical processes; depositing the amorphous-phase TiO 2 dielectric layer onto the protective layer by CVD, ALD, or wet chemical processes; depositing the barrier layer onto the amorphous-phase TiO 2 dielectric layer by ALD; depositing the metallic absorbing layer onto the barrier layer by ALD; and depositing the dielectric outer layer onto the metallic absorbing layer by CVD or ALD.

27 . A paint system comprising:
a binder; and a multilayer thin film of claim 1 .

28 . An automotive vehicle comprising the paint system of claim 27 .

29 . A paint system comprising:
a binder; and a multilayer thin film of claim 11 .

30 . An automotive vehicle comprising the paint system of claim 29 .

Assignees

• Toyota Eng & Mfg North America
• Toyota Motor Co Ltd

Inventors

• Banerjee Debasish
• Wu Songtao
• ASANO Hidetaka

Classifications

• B32B7/023

  Optical properties · CPC title

• C09D5/36

  Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre · CPC title

• C09D7/70

  characterised by shape, e.g. fibres, flakes or microspheres · CPC title

• G02B5/26

  Reflecting filters (G02B5/28 takes precedence) · CPC title

• G02B5/22 Primary

  Absorbing filters {(G02B5/201 - G02B5/208 take precedence)} · CPC title