Optical laminate with polarizing film

Patent metadata

Field	Value
Publication number	US-9354372-B2
Application number	US-201414647534-A
Country	US
Kind code	B2
Filing date	Feb 6, 2014
Priority date	Feb 7, 2013
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

An optical laminate in which a polarizing film including a polyvinyl alcohol-based resin having oriented iodine is bonded on a first surface of the polarizing film to an optical film through an optically transparent adhesive layer is provided. The polarizing film exhibits a property that a value expressed by the following formula: Aa×(Is/Ia), is 0.53 or more, where: Aa represents an absorbance; Ia represents a value obtained by integrating a distribution of integrated intensities in the thickness direction of the polarizing film; and Is represents a value obtained by integrating, a distribution of integrated intensities in the thickness direction of the polarizing film; and the adhesive layer exhibits a property that a difference between a refractive index of the adhesive layer and a refractive index in the absorption axis direction of the polarizing film at the first surface of the polarizing film is 0.08 or less.

First claim

What is claimed is:

1. An optical laminate in which a polarizing film comprised of a polyvinyl alcohol-based resin having oriented iodine is bonded on a first surface of the polarizing film to an optical film through an optically transparent adhesive layer, wherein:
the polarizing film exhibits a property that a value expressed by the following formula: Aa×(Is/Ia), is 0.53 or more, where:
Aa represents an absorbance in an absorption axis direction of the polarizing film at a wavelength of 480 nm;
Ia represents a value obtained by integrating, over an entire interval in a thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating a Raman spectrum of the polarizing film in a wavenumber interval of 90 cm −1 to 120 cm −1 ; and
Is represents a value obtained by integrating, over the entire interval in the thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating, in a wavenumber interval of 90 cm −1 to 120 cm −1 , Raman scattering of I 3 − ions which exist in a region of the polarizing film ranging from the first surface to 1 μm inward in the thickness direction thereof, and oriented in the absorption axis direction of the polarizing film; and

the adhesive layer exhibits a property that a difference between a refractive index of the adhesive layer and a refractive index in the absorption axis direction of the polarizing film at the first surface of the polarizing film is 0.08 or less.

2. The optical laminate as defined in claim 1 , wherein the difference between the refractive index in the absorption axis direction of the polarizing film at the first surface thereof and the refractive index of the adhesive layer is 0.06 or less.

3. The optical laminate as defined in claim 1 , wherein the difference between the refractive index of the optical film and the refractive index of the adhesive layer is 0.10 or less.

4. The optical laminate as defined in claim 1 , wherein the adhesive layer is formed using a solution containing a polyvinyl alcohol-based resin, a cross-linking agent and a colloidal metal compound.

5. The optical laminate as defined in claim 1 , wherein the optical film is a protective layer made of a transparent resin material.

6. The optical laminate as defined in claim 5 , wherein a hard coat layer is formed on the protective layer made of a transparent resin material.

7. The optical laminate as defined in claim 1 , which further comprises a protective layer made of a transparent resin material.

8. The optical laminate as defined in claim 1 , which comprises a retardation film.

9. The optical laminate as defined in claim 1 , where the value of expressed by the formula Aa×(Is/Ia) is 0.55 or more.

10. The optical laminate as defined in claim 1 , wherein the polarizing film has a thickness of 10 μm or less.

11. The optical laminate as defined in claim 1 , wherein the polarizing film has a thickness of 7 μm or less.

12. The optical laminate as defined in claim 1 , wherein the polarizing film has a thickness of 5 μm or less.

13. A display comprising the optical laminate as defined in claim 1 .

14. An optical laminate comprising a polarizing film comprised of a polyvinyl alcohol-based resin having oriented iodine, and a sub-laminate, wherein:
the sub-laminate comprises at least an optically transparent adhesive layer and an optical film, wherein the optical film is bonded to a first surface of the polarizing film through the optically transparent adhesive layer;
the polarizing film exhibits a property that a value expressed by the following formula: Aa×(Is/Ia), is 0.53 or more, where:
Aa represents an absorbance in an absorption axis direction of the polarizing film at a wavelength of 480 nm;
Ia represents a value obtained by integrating, over an entire interval in a thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating a Raman spectrum of the polarizing film in a wavenumber interval of 90 cm −1 to 120 cm −1 ; and
Is represents a value obtained by integrating, over the entire interval in the thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating, in a wavenumber interval of 90 cm −1 to 120 cm −1 , Raman scattering of I 3 − ions which exist in a region of the polarizing film ranging from the first surface to 1 μm inward in the thickness direction thereof, and oriented in the absorption axis direction of the polarizing film; and

the sub-laminate has a thickness of 60 μm or more.

15. The optical laminate as defined in claim 14 , wherein the sub-laminate has a thickness of 80 μm or more.

16. An optical laminate comprising a polarizing film comprised of a polyvinyl alcohol-based resin having oriented iodine, and a sub-laminate, wherein:
the sub-laminate comprises at least an optically transparent adhesive layer and an optical film, wherein the optical film is bonded to a first surface of the polarizing film through the optically transparent adhesive layer;
the polarizing film exhibits a property that a value expressed by the following formula: Aa×(Is/Ia), is 0.53 or more, where:
Aa represents an absorbance in an absorption axis direction of the polarizing film at a wavelength of 480 nm;
Ia represents a value obtained by integrating, over an entire interval in a thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating a Raman spectrum of the polarizing film in a wavenumber interval of 90 cm −1 to 120 cm −1 ; and
Is represents a value obtained by integrating, over the entire interval in the thickness direction of the polarizing film, a distribution of integrated intensities in the thickness direction of the polarizing film, wherein each of the integrated intensities is obtained by integrating, in a wavenumber interval of 90 cm −1 to 120 cm −1 , Raman scattering of I 3 − ions which exist in a region of the polarizing film ranging from the first surface to 1 μm inward in the thickness direction thereof, and oriented in the absorption axis direction of the polarizing film; and

the sub-laminate has a Haze value of 0.5% or more.

17. The optical laminate as defined in claim 16 , wherein the sub-laminate has a Haze value of 1.5% or more.

18. The optical laminate as defined in claim 16 , wherein the sub-laminate has a Haze value of 10% or more.

Assignees

• Nitto Denko Corp

Inventors

• Kamijo Takashi
• Izaki Akinori
• Kitagawa Takeharu
• Goto Shusaku
• Nakagawa Daigoro

Classifications

• G02B1/111

  using layers comprising organic materials · CPC title

• B32B2457/20

  Displays, e.g. liquid crystal displays, plasma displays · 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

• B32B7/12 Primary

  using interposed adhesives or interposed materials with bonding properties · CPC title

• G02B5/3033 Primary

  in the form of a thin sheet or foil, e.g. Polaroid · CPC title