Omnidirectional high chroma red structural color with combination metal absorber and dielectric absorber layers

• US 9,658,375 B2
• Filed: 07/07/2015
• Issued: 05/23/2017
• Est. Priority Date: 08/10/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Banerjee, Debasish
• Primary Examiner(s): Cherry, Euncha
• Application Number:
  US14/793,133
• Publication Number:
  US 20150309232A1
• Time in Patent Office: 686 Days
• Field of Search: 359577-590, 428620, 428621, 428622, 428623, 428641, 106404, 106415
• CPC Class Codes: G02B 5/0825 the reflecting layers comprising dielectric materials only
• CPC Class Codes: G02B 5/0858 the reflecting layers comprising a single metallic layer with one or more dielectric layers
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence
• CPC Class Codes: G02B 5/286 having four or fewer layers, e.g. for achieving a colour effect

Abstract

A high-chroma omnidirectional red structural color pigment. The omnidirectional structural color pigment is in the form of a multilayer stack that has a reflective core layer, a metal absorber layer extending across the reflective core layer and a dielectric absorber layer extending across the metal absorber layer. The multilayer stack reflects a single band of visible light with a hue between 0-40°, and preferably between 10-30°, on an a*b* Lab color map. The single band of visible light has a hue shift of less than 30° on the a*b* Lab color map when viewed from all angles between 0-45° normal to an outer surface of the multilayer stack.

Claims

1. An omnidirectional high chroma red structural color comprising:

a multilayer stack having;

a reflective core layer;

a metal absorber layer extending across said reflective core layer; and

a dielectric absorber layer extending across said metal absorber layer;

said multilayer stack reflecting a single band of visible light with a hue between 0-40°

on an a*b* Lab color map, said single band of visible light having a hue shift within said 0-40°

on said a*b* Lab color map when viewed from all angles between 0-45°

normal to an outer surface of said multilayer stack.

2. The omnidirectional high chroma red structural color of claim 1, wherein said hue is between 10-30°

and said hue shift is within said 10-30°

on said a*b* Lab color map.

3. The omnidirectional high chroma red structural color of claim 1, wherein said reflective core layer has a thickness between 50-200 nanometers, inclusive.

4. The omnidirectional high chroma red structural color of claim 3, wherein said reflective core layer is made from a reflective metal selected from the group consisting of Al, Ag, Pt, Sn and combinations thereof.

5. The omnidirectional high chroma red structural color of claim 3, wherein said reflective core layer is made from a colorful metal selected from the group consisting of Au, Cu, brass, bronze and combinations thereof.

6. The omnidirectional high chroma red structural color of claim 3, wherein said metal absorber layer has a thickness between 5-500 nanometers, inclusive.

7. The omnidirectional high chroma red structural color of claim 6, wherein said metal absorber layer is made from the group consisting of Cu, bronze, brass, amorphous Si, Ge, TiN and combinations thereof.

8. The omnidirectional high chroma red structural color of claim 6, wherein said dielectric absorber layer has a thickness between 5-500 nanometers, inclusive.

9. The omnidirectional high chroma red structural color of claim 8, wherein said dielectric absorber layer is made from Fe₂O₃.

10. The omnidirectional high chroma red structural color of claim 6, wherein said reflective core layer is a central reflective core layer and said metal absorber layer is a pair of metal absorber layers extending across opposite sides of said central reflective core layer, said central reflective core layer sandwiched between said pair of metal absorber layers.

11. The omnidirectional high chroma red structural color of claim 10, wherein said dielectric absorber layer is a pair of dielectric absorber layers, said central reflective core layer and said pair of metal absorber layers sandwiched between said pair of dielectric absorber layers.

12. A process for making an omnidirectional high chroma red structural color, the process comprising:

manufacturing a multilayer stack by;

dry depositing a reflective core layer;

dry depositing a metal absorber layer that extends across the reflective core layer;

dry or wet depositing a dielectric absorber layer that extends across the metal absorber layer; and

the multilayer stack reflecting visible light with a hue between 0-40°

on an a*b* Lab color map and having a hue shift within the 0-40°

on the a*b* Lab color map when viewed from all angles between 0-45°

normal to an outer surface of the multilayer stack.

13. The process of claim 12, wherein the multilayer stack reflects visible light with a hue between 10-30°

on the a*b* Lab color map and has the hue shift between the 10-30°

on the a*b* Lab color map.

14. The process of claim 12, wherein the reflective core layer has a thickness between 50-200 nanometers, inclusive.

15. The process of claim 14, wherein said reflective core layer is made from a reflective metal selected from the group consisting of Al, Ag, Pt, Sn and combinations thereof.

16. The process of claim 14, wherein the reflective core layer is made from a colorful metal selected from the group consisting of Au, Cu, brass, bronze and combinations thereof.

17. The process of claim 14, wherein the metal absorber layer has a thickness between 5-500 nanometers, inclusive.

18. The process of claim 17, wherein the metal absorber layer is made from the group consisting of Cu, bronze, brass, amorphous Si, Ge, TiN and combinations thereof.

19. The process of claim 17, wherein the dielectric absorber layer has a thickness between 5-500 nanometers, inclusive, and is made from Fe₂O₃.