COLOR DEVELOPING STRUCTURE, DISPLAY, AND METHOD FOR PRODUCING COLOR DEVELOPING STRUCTURE

• US 20200132900A1
• Filed: 12/20/2019
• Published: 04/30/2020
• Est. Priority Date: 06/28/2017
• Status: Active Grant

• Current Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Original Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Inventors: FURUTA, Kaoru, MICHI, Hiroyuki, KAWASHITA, Masashi
• Granted Patent: US 11,592,605 B2
• Time in Patent Office: Days
• CPC Class Codes: B32B 7/02 Physical, chemical or physicochemical properties
• CPC Class Codes: B32B 7/023 Optical properties
• CPC Class Codes: B41M 1/10 Intaglio printing ; Gravure printing
• CPC Class Codes: B41M 3/14 Security printing securities B42D25/29
• CPC Class Codes: B42D 25/324 Reliefs
• CPC Class Codes: B42D 25/328 Diffraction gratings; Holograms
• CPC Class Codes: B42D 25/36 comprising special materials
• CPC Class Codes: B42D 25/373 Metallic materials
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 5/1809 with pitch less than or comparable to the wavelength
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• CPC Class Codes: G02B 5/203 having holographic or diffractive elements diffraction gratings per se G02B5/18; holographic elements per se G02B5/32; generating the spectrum using diffraction elements G01J3/18
• CPC Class Codes: G02B 5/28 Interference filters
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361

Abstract

A color developing structure that exhibits good color development and ensures a desired transmittance while diffusing reflected light in multiple directions. A color developing structure includes a concave-convex layer in which a first surface has a concave-convex structure, and a reflective layer formed on the first surface to extend along the concave-convex structure. A convex surface of the concave-convex structure has a first pattern composed of a plurality of strip portions in plan view. The strip portion has a width in a first direction and a length in a second direction perpendicular to the first direction. The width is smaller than the wavelength of the incident light, and a standard deviation of the lengths of the plurality of strip portions is larger than a standard deviation of the widths.

Claims

1. A color developing structure, comprising:

a concave-convex layer having a first surface, and a second surface located on a side facing away from the first surface, the first surface being provided with a concave-convex structure; and

a functional layer located on the first surface or the second surface of the concave-convex layer, wherein

a convex surface of the concave-convex structure has a first pattern composed of a plurality of strip portions in plan view, and the strip portion has a width in a first direction and a length in a second direction perpendicular to the first direction, the width is smaller than a wavelength of incident light, and a standard deviation of the lengths of the plurality of strip portions is larger than a standard deviation of the widths.

2. The color developing structure of claim 1, wherein

the convex surface of the concave-convex structure has the first pattern and a second pattern that partially overlaps the first pattern in plan view such that the first pattern and the second pattern overlapped form a multi-stage shape,

the second pattern is composed of a plurality of second strip portions in plan view, and each of the second strip portions has a width in the first direction and a length in the second direction perpendicular to the first direction, and

arrangement intervals of the plurality of second strip portions in the first direction are not constant, and an average of the arrangement intervals is equal to or more than ½

of a minimum wavelength in a wavelength range of incident light.

3. The color developing structure of claim 1, wherein a material for forming the concave-convex layer is a composite having a refractive index in the visible light region of 1.4 or more and 3.0 or less, or a composite including an inorganic compound having an extinction coefficient of 2 or more and 6 or less.

4. The color developing structure of claim 1, further comprising an interference layer that follows a surface shape of the concave-convex structure.

5. The color developing structure of claim 4, wherein a material for forming the interference layer includes a compound having a refractive index difference of 0.2 or more and 0.8 or less relative to the concave-convex layer.

6. The color developing structure of claim 4, wherein the functional layer is a reflective layer, and a material for forming the interference layer includes a compound having a refractive index difference of 0.6 or more and 1.5 or less relative to the reflective layer.

7. The color developing structure of claim 1, wherein the functional layer is a reflective layer, and the reflective layer is disposed on the first surface and follows a surface shape of the concave-convex structure.

8. The color developing structure of claim 1, wherein the functional layer is a reflective layer, and the reflective layer is disposed on the second surface of the concave-convex layer.

9. The color developing structure of claim 8, wherein the concave-convex layer has a thickness in a range of 20 nm or more and 1000 nm or less between the first surface and the second surface.

10. The color developing structure of claim 4, wherein the functional layer is an antireflection layer, and the antireflection layer is disposed on the second surface of the concave-convex layer.

11. The color developing structure of claim 10, wherein

the antireflection layer has a second concave-convex structure on a side facing away from the concave-convex layer,

the second concave-convex structure has a height of 10 nm or more and 500 nm or less in a film thickness direction,

convex portions constituting the second concave-convex structure are arranged in any one of an irregular arrangement, a square arrangement, and a hexagonal arrangement, or an island-like pattern formed by combining these,

a structural periodicity of the second concave-convex structure is in a range of 10 nm or more and 1000 nm or less, and

a ratio of a width of the structural periodicity of the second concave-convex structure to a width of a concave portion constituting the second concave-convex structure is in a range of 0.25 or more and 0.75 or less.

12. The color developing structure of claim 10, wherein

the antireflection layer has a second concave-convex structure on a side facing away from the concave-convex layer,

the second concave-convex structure has a height of 10 nm or more and 200 nm or less in a film thickness direction,

convex portions constituting the second concave-convex structure are arranged in any one of an irregular arrangement, a square arrangement, and a hexagonal arrangement, or an island-like pattern formed by combining these,

the color developing structure further comprises a reflective layer that follows a surface shape of the second concave-convex structure,

a structural periodicity of the second concave-convex structure and a structural periodicity of the reflective layer are a subwavelength periodicity, which is equal to or less than a wavelength in the visible region, and

a ratio of a width of the structural periodicity of the second concave-convex structure to a width of a concave portion of the second concave-convex structure, and a ratio of a width of a convex portion of a concave-convex structure of the reflective layer to a width of a concave portion of the concave-convex structure of the reflective layer which follows the second concave-convex structure are in a range of 0.25 or more and 0.75 or less.

13. The color developing structure of claim 10, wherein the antireflection layer includes a black pigment.

14. The color developing structure of claim 10, wherein the interference layer includes one or more compounds including an inorganic substance or an inorganic composite material having a refractive index of 1.3 or more and 4.0 or less.

15. The color developing structure of claim 10, wherein the interference layer has a multilayer film configuration in which a high refractive index compound and a low refractive index compound are alternately laminated, and a refractive index difference between the high refractive index compound and the low refractive index compound is in a range of 0.6 or more and 2.2 or less.

16. The color developing structure of claim 6, wherein the reflective layer is made of one or more materials selected from the group consisting of metal, metal alloy, and metal composite material, and the selected material satisfies one or both of a refractive index in the visible light region of 0.2 or more and 5.0 or less and an extinction coefficient in the visible light region of 2 or more and 6 or less.

17. A display comprising a display element formed of the color developing structure of claim 1.

18. The display of claim 17, wherein

a plurality of the display elements are disposed in a plane, and

two display elements selected from the plurality of the display elements, that is, a first display element and a second display element, constitute color developing structures having layer configurations which are the same in material and film thickness and different in height of a convex portion of the concave-convex structure.

19. A watch dial having the display of claim 17.

20. An automobile component having the display of claim 17.

21. A method for producing the color developing structure of claim 1, comprising a step of forming the concave-convex structure by transferring a concave-convex pattern of an intaglio plate to a resin by nanoimprinting.