Optical film, and polarizing plate, surface plate, image display panel and image display device using the optical film, and method for producing the optical film, and method for selecting optical film, and evaluation method of finger print wiping property

Patent metadata

Field	Value
Publication number	US-2025155605-A1
Application number	US-202519022618-A
Country	US
Kind code	A1
Filing date	Jan 15, 2025
Priority date	Sep 30, 2022
Publication date	May 15, 2025
Grant date	—

Abstract

An optical film having high anti-glare properties and favorable fingerprints wiping off properties is provided. The optical film has a first surface, and a second surface which is a surface opposite to the first surface, wherein the optical film comprises an anti-reflection layer and an anti-glare layer in this order from the first surface to the second surface, the first surface has a profile of depressions and projections, the first surface has an arithmetic mean height Sa of 0.05 μm or more specified in ISO 25178-2:2012, and the first surface satisfies the relation represented by the following Expression 1: Sw×Vmp≤2.00 (Expression 1) wherein “Sw” represents a tilt angle (degrees) of 30 μl pure water droplet flowing down on the first surface; and “Vmp” represents a value of a peak material volume (ml/m 2 ) of the first surface specified in ISO 25178-2:2012.

First claim

The invention claimed is:

1 . An optical film having a first surface, and a second surface which is a surface opposite to the first surface,
wherein the optical film comprises an anti-reflection layer and an anti-glare layer in this order from the first surface to the second surface, the first surface has a profile of depressions and projections, the first surface has an arithmetic mean height Sa of 0.05 μm or more specified in ISO 25178-2:2012, and the first surface satisfies the relation represented by the following Expression 1:

Sw
×
Vmp

≤
2.

(

Expression
⁢

1

)

wherein “Sw” represents a tilt angle (degrees) of 30 μl pure water droplet flowing down on the first surface; and “Vmp” represents a value of a peak material volume (ml/m 2 ) of the first surface specified in ISO 25178-2:2012.

2 . The optical film according to claim 1 , wherein the first surface has a Vmp of 0.005 ml/m 2 or more and 0.100 ml/m 2 or less.

3 . The optical film according to claim 1 , wherein the first surface has a dale void volume Vvv of 0.005 ml/m 2 or more and 0.100 ml/m 2 or less, the dale void volume Vvv being specified in ISO 25178-2:2012 and being calculated where an areal material ratio that separates a core portion and a reduced dale is 80%.

4 . The optical film according to claim 3 , wherein the first surface has a ratio of the Vvv to a Vvc (Vvv/Vvc) of 0.10 or less, the Vvc being a core void volume specified in ISO 25178-2:2012.

5 . The optical film according to claim 1 , wherein the first surface has a minimum autocorrelation length Sal of 4.0 μm or more and 12.0 μm or less specified in ISO 25178-2:2012.

6 . The optical film according to claim 1 , wherein the optical film comprises the anti-reflection layer, the anti-glare layer, and a substrate in this order from the first surface to the second surface.

7 . The optical film according to claim 1 , wherein the anti-glare layer contains a binder resin and particles.

8 . The optical film according to claim 1 , wherein the optical film has elemental ratios obtained by analysis of a surface region on the first surface side by X-ray photoelectron spectroscopy and satisfying the relations represented by the following Expressions 2 to 4:

3.5
≤

F
/
inorganic
⁢

Si

≤
10.

(

Expression
⁢

2

)

0.08
≤

organic
⁢

Si
/
inorganic
⁢

Si

≤
1.

(

Expression
⁢

3

)

5.
≤

F
/
organic
⁢

Si

≤
50.

(

Expression
⁢

4

)

wherein “F” represents a ratio of a fluorine element, “inorganic Si” represents a ratio of a silicon element attributed to an inorganic silicon compound, and “organic Si” represents a ratio of a silicon element attributed to an organic silicon compound.

9 . The optical film according to claim 8 , wherein a proportion of the inorganic Si relative to the total elements is 2 atomic percent or more and 20 atomic percent or less for the elemental ratios obtained by analysis by the X-ray photoelectron spectroscopy.

10 . The optical film according to claim 1 , wherein the optical film has a total luminous reflectance R SCI of 3.0% or less measured by the following method:
bonding a black plate to the second surface of the optical film with a transparent adhesive to prepare a sample; and measuring the total luminous reflectance (R SCI ) of the optical film side of the sample as a light incident surface.

11 . The optical film according to claim 1 , having a haze specified in JIS K7136: 2000 of 20% or more and 75% or less.

12 . A polarization plate comprising a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer,
wherein at least one of the first transparent protective plate and the second transparent protective plate is the optical film according to claim 1 , and the second surface of the optical film is disposed facing the polarizer.

13 . A surface plate for an image display device, comprising a protective film bonded onto a resin plate or a glass plate, wherein the protective film is the optical film according to claim 1 , and the second surface of the optical film is disposed facing the resin plate or the glass plate.

14 . An image display panel comprising a display element, and an optical film disposed on a light-emitting surface side of the display element, wherein, as the optical film, the optical film according to claim 1 is included.

15 . An image display device comprising the image display panel according to claim 14 .

16 . A method of producing the optical film according to claim 1 , the method comprising:
a first step of forming an anti-glare layer on a substrate; and a second step of forming an anti-reflection layer on the anti-glare layer.

17 . A method of selecting a

Assignees

• Dainippon Printing Co Ltd

Inventors

• Tsujimoto Jun
• Iwata Yukimitsu
• Takei Michiaki
• Tanaka Masafumi
• Ikeda Keisuke
• Furui Gen

Classifications

• G02B5/3025

  Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence) · CPC title

• G02B5/0247

  by means of voids or pores · CPC title

• G02B1/111

  using layers comprising organic materials · CPC title

• G02B1/18 Primary

  Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films (G02B1/16 takes precedence) · CPC title

• G02B5/30

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title