Optical laminate

Patent metadata

Field	Value
Publication number	US-10989849-B2
Application number	US-201916253209-A
Country	US
Kind code	B2
Filing date	Jan 21, 2019
Priority date	Aug 30, 2016
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

An optical laminate includes a wavelength selective reflective element, and an absolute phase adjustment layer which is provided on at least one surface side of the wavelength selective reflective element and has optical isotropy, and in which a first region having a first optical path length and a second region having a second optical path length different from the first optical path length are arranged in a pattern with a diffraction grating-like period. The optical laminate reflects light in the specific reflection wavelength region by the wavelength selective reflective element, of light incident from the absolute phase adjustment layer side. In the optical laminate, light which enters the first region of the absolute phase adjustment layer and is reflected by the wavelength selective reflective element and light which enters the second region and is reflected by the wavelength selective reflective element interfere with each other.

First claim

What is claimed is:

1. An optical laminate comprising:
a wavelength selective reflective element which is provided with a reflection layer selectively reflecting light in a specific reflection wavelength region; and
an absolute phase adjustment layer which is provided on at least one surface side of the wavelength selective reflective element and has optical isotropy, and in which a first region having a first optical thickness and a second region having a second optical thickness different from the first optical thickness are arranged in a pattern with a diffraction grating-like period, and
wherein the optical laminate reflects light in the specific reflection wavelength region by the wavelength selective reflective element, of light incident from the absolute phase adjustment layer side, and
light which enters the first region and is reflected by the wavelength selective reflective element and light which enters the second region and is reflected by the wavelength selective reflective element interfere with each other,
wherein in the wavelength selective reflective element, two or more reflection layers having different reflection wavelength regions are arranged in a pattern with a larger period than the period, and
wherein interface between the reflective element and the absolute phase adjustment layer is flat, the interface covers the first and the second optical thicknesses.

2. The optical laminate according to claim 1 ,
wherein the reflection layer of the wavelength selective reflective element is formed of a cholesteric liquid crystal layer.

3. The optical laminate according to claim 1 ,
wherein the reflection layer of the wavelength selective reflective element is formed of a dielectric multilayer film in which at least two layers having different refractive indices are alternately laminated in multiple layers.

4. The optical laminate according to claim 1 ,
wherein the first region and the second region of the absolute phase adjustment layer are different from each other in at least one of a refractive index or a film thickness.

5. The optical laminate according to claim 1 ,
wherein an optical thickness difference between the first optical thickness and the second optical thickness is 0.27λ to 0.45λ where λ is a central wavelength of the specific reflection wavelength region.

6. The optical laminate according to claim 1 ,
wherein the period of the pattern is 0.6 μm to 2.0 μm.

7. The optical laminate according to claim 1 ,
wherein the first region has a refractive index of 1.4 to 1.6, and
the second region has a refractive index of 1.8 to 2.0.

8. The optical laminate according to claim 1 ,
wherein a diffusion plate is provided on a surface side of the absolute phase adjustment layer, opposed to a surface on which the wavelength selective reflective element is disposed.

9. The optical laminate according to claim 1 ,
wherein the first region and the second region have the same stripe shape, and are alternately arranged in a width direction of the stripe shape.

10. The optical laminate according to claim 1 ,
wherein the first region and the second region have the same rectangular shape, and are alternately arranged in horizontal and vertical directions.

11. The optical laminate according to claim 1 ,
wherein the absolute phase adjustment layer is provided with an intermediate region having an optical thickness between the first optical thickness and the second optical thickness, and
the intermediate region is arranged together with the first region and the second region in the pattern with the period.

12. The optical laminate according to claim 1 ,
wherein the wavelength selective reflective element is formed by laminating two or more reflection layers having different reflection wavelength regions.

13. An optical laminate which is formed by laminating the optical laminate according to claim 1 in multiple layers.

Assignees

• Fujifilm Corp

Inventors

• Satake Ryo
• Saitoh Yukito
• Kashiwagi Daisuke

Classifications

• G02B5/1814

  structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings (G02B5/189 takes precedence) · CPC title

• G02F1/1335

  Structural association of cells with optical devices, e.g. polarisers or reflectors · CPC title

• G02B5/26

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

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G02B5/201

  in the form of arrays · CPC title