Sheet of colloidal crystals immobilized in resin, method of displaying structural color using same, method for detecting unevenness distribution or hardness distribution of subject using same, and structural color sheet

Patent metadata

Field	Value
Publication number	US-9970749-B2
Application number	US-201414910431-A
Country	US
Kind code	B2
Filing date	Aug 5, 2014
Priority date	Aug 6, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

Provided are: a sheet of colloidal crystals immobilized in resin exhibiting intense structural color, enabled to be observed easily from a squarely facing direction against a surface; and use thereof. The sheet of the present invention, assuming a direction perpendicular to part of a surface of a target area including partially the sheet surface is set as a specified axis, satisfies: (1) The target area includes plural inclined back-reflecting crystal-domains crystal domains having colloid particles immobilized in resin and including crystal lattice planes capable of Bragg-back reflecting at least some of components in a visible wavelength range of incident light having greater than 0 incident angle with the specified axis; and (2) By defining an azimuth angle around the specified axis, the inclined back-reflecting crystal-domains are so oriented that intensity of reflected light caused by Bragg back reflection varies depending on the azimuth angle of the incident light.

First claim

What is claimed is:

1. A sheet of colloidal crystals immobilized in resin wherein a target area includes at least part of a surface of the sheet of colloidal crystals immobilized in resin and a specified axis that is a perpendicular direction to the surface, the sheet of colloidal crystals immobilized in resin satisfying:
(1) the target area includes a plurality of crystal domains including colloidal particles immobilized in resin and crystal lattice planes capable of substantially Bragg-back reflecting at least part of components in a visible wavelength range of incident light having an incident angle of greater than 0 formed with the specified axis; and
(2) the plurality of crystal-domains are so oriented that intensity of reflected light caused by the Bragg back reflection varies depending on the azimuth angle of the incident light around the specified axis such that at least one peak is obtained in a plotted graph having an evaluation axis for intensity thereof and a variable axis for an azimuth angle thereof when measurement of the Bragg back reflection is conducted with a changing azimuth angle of the incident light,
wherein the plurality of crystal domains are so oriented that a normal line of the crystal lattice planes in each of the plurality of crystal domains causing the Bragg back reflection forms an angle of at least greater than 0 degrees and not exceeding 15 degrees with the specified axis,
wherein the sheet of colloidal crystals immobilized in resin is manufactured by a method including a shearing treatment process in which shearing force is applied in a shearing direction that is a reference direction of the azimuth angle and parallel to the surface of the target area, and
wherein an azimuth angle of the at least one peak obtained by the measurement of the Bragg back reflection is in a range of from 80 degrees to 100 degrees.

2. The sheet of colloidal crystals immobilized in resin according to claim 1
wherein another crystal domain including crystal lattice planes having a normal line that forms an angle of greater than 15 degrees and not exceeding 20 degrees with the specified axis is included.

3. The sheet of colloidal crystals immobilized in resin according to claim 1
wherein a particle concentration of the colloidal particles is at least 2 vol % and not exceeding 35 vol %.

4. The sheet of colloidal crystals immobilized in resin according to claim 1
wherein the resin is selected from the group consisting of acrylic resin, epoxy resin, siloxane resin (silicone), urethane resin, polyester resin, alkyd resin, fluorine resin, and polyether resin.

5. The sheet of colloidal crystals immobilized in resin according to claim 4
wherein the resin is acrylic resin and
wherein a compound to form the acrylic resin is at least one selected from the group consisting of methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, methoxy triethylene glycol (meth)acrylate, methoxy tetraethylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, ethylene di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

6. The sheet of colloidal crystals immobilized in resin according to claim 4
wherein the resin is epoxy resin and
wherein a compound to form the epoxy resin comprises a diglycidyl ester derivative compound and/or a diglycidyl ether derivative compound, and a phthalic anhydride derivative compound.

7. The sheet of colloidal crystals immobilized in resin according to claim 6
wherein the diglycidyl ester derivative compound is phthalic acid diglycidyl ester and/or hexahydrophthalic acid diglycidyl ester.

8. The sheet of colloidal crystals immobilized in resin according to claim 6
wherein the diglycidyl ether derivative compound is at least one selected from the group consisting of glycerol polyglycidyl ether; 1,4-butanediol diglycidyl ether; and bisphenol-A diglycidyl ether.

9. The sheet of colloidal crystals immobilized in resin according to claim 6
wherein the phthalic anhydride derivative compound is 4-methylhexahydrophthalic anhydride and/or hexahydrophthalic anhydride.

10. The sheet of colloidal crystals immobilized in resin according to claim 1
wherein a thickness of the sheet of colloidal crystals immobilized in resin is more than 0.3 mm and not exceeding 10 mm.

11. A method of displaying a structural color based on colloidal crystals
wherein the method comprising the step of irradiating a sheet of colloidal crystals immobilized in resin according to claim 1 with illumination light.

12. The method according to claim 11
wherein the step of irradiating the sheet with the illumination light is characterized by irradiating the sheet with the illumination light from a direction different from a squarely facing direction against a sheet surface of the sheet of colloidal crystals immobilized in resin.

13. The method according to claim 11
wherein the sheet of colloidal crystals immobilized in resin is manufactured by applying a shearing treatment; and
wherein the step of irradiating the sheet with the illumination light is characterized by irradiating the sheet with the illumination light from a direction having an azimuth angle perpendicular to a shearing direction of the shearing treatment.

14. The method according to claim 11
wherein the sheet of colloidal crystals immobilized in resin has a pattern comprising a character or a figure.

15. The method according to claim 11
wherein the sheet of colloidal crystals immobilized in resin is sandwiched at least between a hard transparent plate and a relief plate in which a pattern comprising a character or a figure is formed with a convex and/or a concave; and
wherein the method comprises the step of pressing the sheet of colloidal crystals immobilized in resin with the hard transparent plate prior to the step of irradiating the sheet with the illumination light.

16. A method of detecting an unevenness distribution or a hardness distribution of a test object comprises the steps of:
covering the test object with a sheet of colloidal crystals immobilized in resin according to claim 1 and pressing the sheet with a hard transparent plate;
irradiating the sheet of colloidal crystals immobilized in resin with illumination light and observing the sheet of colloidal crystals immobilized in resin through the hard transparent plate; and
detecting an unevenness distribution or a hardness distribution based on an observation result obtained in the step of observation.

17. The method according to claim 16
wherein the step of observation comprises irradiating the sheet with the illumination light from a direction different from a squarely facing direction against a sheet surface of the sheet of colloidal crystals immobilized in resin and observing the sheet.

18. The method according to claim 16
wherein the step of detection comprises:
detecting that the test object does not have the unevenness distribution or the hardness distribution when the observation result is same as that of the sheet of colloidal crystals immobilized in resin prior to the step of pressing; and
detecting that the test object has the unevenness distribution or the hardness distribution when the observation result is different from that of the sheet of collo

Assignees

• Fuji Kagaku Corp
• Nat Inst Materials Science

Inventors

• Kawanaka Satoshi
• Uchida Fumio
• Sawada Tsutomu
• Furumi Seiichi
• Fudoji Hiroshi

Classifications

• G02B5/26

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

• G02B5/28

  Interference filters · CPC title

• G02B1/04 Primary

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• G01B11/24 Primary

  for measuring contours or curvatures · CPC title

• G02B1/005

  made of photonic crystals or photonic band gap materials (photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295) · CPC title