Granted Patent B2

US 12,210,174 · App. 18/217,810 · Granted Jan 28, 2025

Inventors: Debasish Banerjee (Ann Arbor, MI); Minjuan Zhang (Ann Arbor, MI); Masahiko Ishii (Okazaki, JP)

Assignees: Toyota Motor Engineering & Manufacturing North America, Inc.; Toyota Jidosha Kabushiki Kaisha

G02B5/0858G02B5/085G02B5/26G02B5/285G02B5/286

Abstract

Claims (29)

1. A multilayer thin film that reflects an omnidirectional structural color comprising: a multilayer stack comprising:

a reflector layer;

a first dielectric layer extending over the reflector layer;

an absorbing layer extending over the first dielectric layer; and

a second dielectric layer extending over the 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 visible full width at half maximum (FWHM) width of less than 200 nm; and

a color shift of the reflected single narrow band of visible light is less than 50 nm and a hue shift of less than or equal to 30° on the CIELAB color space when the multilayer stack is exposed to broadband electromagnetic radiation and viewed from angles between 0 and 45 degrees relative to a direction normal to an outer surface of the multilayer thin film; and

wherein the multilayer stack reflects a color with a chroma greater than or equal to 76 and less than or equal to 91.

2. The multilayer thin film of claim 1 , wherein:

the first dielectric layer is formed from at least one of SiO 2 , TiO 2 , ZnS, and MgF 2 ;

the absorbing layer is formed from at least one of Cr, Ta, W, Mo, Ti, TiN, Nb, Co, Si, Ge, Ni, Pd, and V; and

the second dielectric layer is formed from at least one of SiO 2 , TiO 2 , ZnS, and MgF 2 .

3. The multilayer thin film of claim 2 , wherein the first dielectric layer is formed from ZnS, the absorbing layer is formed from W, and the second dielectric layer is formed from TiO 2 .

4. The multilayer thin film of claim 2 , wherein the first dielectric layer is formed from TiO 2 , the absorbing layer is formed from W, and the dielectric layer is formed from TiO 2 .

5. The multilayer thin film of claim 1 , wherein the first dielectric layer has a thickness between 20-80 nm, the absorbing layer has a thickness between 5-20 nm and the second dielectric layer has a thickness between 30-300 nm.

6. The multilayer thin film of claim 1 , wherein the hue shift is less than 25° when the multilayer stack is exposed to broadband electromagnetic radiation and viewed from angles between 0 and 45 degrees.

7. The multilayer thin film of claim 1 , wherein the multilayer stack reflects electromagnetic radiation in the IR range.

8. A multilayer thin film that reflects an omnidirectional structural color comprising:

a multilayer stack comprising a reflector layer, a first dielectric layer extending over the reflector layer, an absorbing layer extending over the first dielectric layer and a second dielectric layer extending over the absorbing layer;

wherein the multilayer thin film reflects visible light and IR radiation when exposed to broadband electromagnetic radiation, the reflected visible light being a single narrow band of visible light comprising:

a visible FWHM width of less than 200 nm; and

a color shift of the reflected single narrow band of visible light is less than 50 nm and a hue shift of less than or equal to 30° on the CIELAB color space when the multilayer stack is exposed to broadband electromagnetic radiation and viewed from angles between 0 and 45 degrees relative to a direction normal to an outer surface of the multilayer thin film; and

wherein the multilayer stack reflects a color with a chroma greater than or equal to 76 and less than or equal to 91.

9. The multilayer thin film of claim 8 , wherein:

the first dielectric layer is formed from at least one of SiO 2 , TiO 2 , ZnS, and MgF 2 ;

the absorbing layer is formed from at least one of Cr, Ta, W, Mo, Ti, TiN, Nb, Co, Si, Ge, Ni, Pd, and V; and

the second dielectric layer is formed from at least one of SiO 2 , TiO 2 , ZnS, and MgF 2 .

10. The multilayer thin film of claim 8 , wherein the first dielectric layer is formed from ZnS, the absorbing layer is formed from W, and the second dielectric layer is formed from TiO 2 .

11. The multilayer thin film of claim 8 , wherein the first dielectric absorbing layer is formed from TiO 2 , the absorbing layer is formed from W, and the second dielectric layer is formed from TiO 2 .

Assignments (3)

Continuity (4)

References Cited (400)