# US 10,481,308 B2 · Optical film, method for manufacturing optical film, and liquid crystal display including optical film

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- Number: US 10,481,308 B2
- Document ID: US10481308B2
- Status: Granted
- Kind: B2
- Application number: 15/364,553
- Filed: 2016-11-30
- Published: 2017-06-01
- Granted: 2019-11-19
- Earliest claimed: 2015-11-30
- Assignees: LG Display Co., Ltd.
- Applicants: LG Display Co., Ltd.
- Inventors: Wonjong Cho; Sudong Roh; Daeheung Lee
- Web page: https://patentgrep.com/patent/US10481308B2

## CPC

- G02B 5/0242: {by means of dispersed particles}
- G02B 5/0226: {having particles on the surface}
- G02B 5/0231: {the surface having microprismatic or micropyramidal shape (macroscopic prism arrays G02B5/045)}
- G02F 1/133504: {Diffusing, scattering, diffracting elements (associated to illuminating devices G02F1/133606)}
- G02F 1/133528: {Polarisers}
- G02B 5/0221: {the surface having an irregular structure (G02B5/0226 takes precedence)}
- G02B 5/0268: {characterized by the fabrication or manufacturing method}
- G02B 5/3025: {Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence)}
- G02F 1/133507: {Films for enhancing the luminance}
- G02F 2202/28: Adhesive materials or arrangements
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

Provided are an optical film, a method for manufacturing an optical film, and a liquid crystal display. An optical film includes: a polarizer, a diffusion sheet adhered to a bottom surface of the polarizer, the diffusion sheet including: a first diffusion member, and a second diffusion member adhered to the first diffusion member, and a prism sheet adhered to a bottom surface of the diffusion sheet.

## Claims

### Claim 1

An optical film, comprising:
a polarizer comprising a polyvinyl alcohol (PVA) core layer;
an ultraviolet (UV) adhesive layer under a bottom surface of the PVA core layer;
a diffusion sheet adhered to a bottom surface of the polarizer, the diffusion sheet comprising:
a first diffusion member comprising a first convex portion, the first diffusion member being adhered to the UV adhesive layer such that the UV adhesive layer is between and directly contacts both of the PVA core layer and the first diffusion member;
a second diffusion member adhered to the first diffusion member, the second diffusion member comprising a second convex portion; and
a first adhesive layer between the first diffusion member and the second diffusion member, the first diffusion member and the second diffusion member being adhered together by the first adhesive layer, the first diffusion member and the second diffusion member contacting the same first adhesive layer; and
a prism sheet adhered to a bottom surface of the diffusion sheet, the prism sheet comprising:
a first prism pattern having a plurality of points at a first height; and
a second prism pattern having a plurality of points at a second height less than the first height, at least one of the plurality of points of the second prism pattern being between at least two of the plurality of points of the first prism pattern.

### Claim 2 (depends on 1)

The optical film of claim 1, wherein the first diffusion member and the second diffusion member are spaced apart from each other.

### Claim 3 (depends on 2)

The optical film of claim 2, wherein a distance between the first diffusion member and the second diffusion member is 0.1 μm to 20 μm.

### Claim 4 (depends on 1)

The optical film of claim 1, wherein each of the first diffusion member and the second diffusion member further comprises a plurality of beads.

### Claim 5 (depends on 4)

The optical film of claim 4, wherein:
each of the first diffusion member and the second diffusion member further comprises an uneven surface attributable to the plurality of beads; and
the uneven surface of the first diffusion member and the uneven surface of the second diffusion member face each other.

### Claim 6 (depends on 1)

The optical film of claim 1, wherein each of the first diffusion member and the second diffusion member has a refractive index of 1.5 to 1.7.

### Claim 7 (depends on 1)

The optical film of claim 1, wherein the adhesive layer has a refractive index of 1.4 to 1.6.

### Claim 8 (depends on 1)

The optical film of claim 1, wherein a refractive index of each of the first diffusion member and the second diffusion member is different from a refractive index of the adhesive layer.

### Claim 9 (depends on 1)

The optical film of claim 1, further comprising a third diffusion member adhered to a bottom surface of the second diffusion member.

### Claim 10 (depends on 9)

The optical film of claim 9, wherein:
the third diffusion member further comprises a third convex portion formed by a plurality of beads; and
a convex direction of the third convex portion is the same as a convex direction of the second convex portion of the second diffusion member adjacent to the third diffusion member.

### Claim 11 (depends on 9)

The optical film of claim 9, further comprising:
a second adhesive layer between the second diffusion member and the third diffusion member,
wherein an interface between the second adhesive layer and the second diffusion member is flat.

### Claim 12

A method for manufacturing an optical film, the method comprising:
providing a polarizer comprising a polyvinyl alcohol (PVA) core layer;
providing an ultraviolet (UV) adhesive layer under a bottom surface of the PVA core layer;
providing a diffusion sheet adhered to a bottom surface of the polarizer, the providing the diffusion sheet comprising:
providing a first diffusion member comprising a first convex portion, the first diffusion member being adhered to the UV adhesive layer such that the UV adhesive layer is between and directly contacts both of the PVA core layer and the first diffusion member;
providing a second diffusion member adhered to the first diffusion member, the second diffusion member comprising a second convex portion; and
providing a first adhesive layer between the first diffusion member and the second diffusion member, the first diffusion member and the second diffusion member being adhered together by the first adhesive layer, the first diffusion member and the second diffusion member contacting the same first adhesive layer; and
providing a prism sheet adhered to a bottom surface of the diffusion sheet, the providing the prism sheet comprising:
providing a first prism pattern having a plurality of points at a first height; and
providing a second prism pattern having a plurality of points at a second height less than the first height, at least one of the plurality of points of the second prism pattern being between at least two of the plurality of points of the first prism pattern.

### Claim 13 (depends on 12)

The method of claim 12, wherein the first diffusion member and the second diffusion member are spaced apart from each other.

### Claim 14 (depends on 13)

The method of claim 13, wherein a distance between the first diffusion member and the second diffusion member is 0.1 μm to 20 μm.

### Claim 15 (depends on 12)

The method of claim 12, wherein the providing each of the first diffusion member and the second diffusion member further comprises providing a plurality of beads.

### Claim 16 (depends on 15)

The method of claim 15, wherein:
the providing each of the first diffusion member and the second diffusion member further comprises providing an uneven surface attributable to the plurality of beads; and
the uneven surface of the first diffusion member and the uneven surface of the second diffusion member face each other.

### Claim 17 (depends on 12)

The method of claim 12, wherein:
each of the first diffusion member and the second diffusion member has a refractive index of 1.5 to 1.7; and
the adhesive layer has a refractive index of 1.4 to 1.6.

### Claim 18 (depends on 12)

The method of claim 12, wherein a refractive index of each of the first diffusion member and the second diffusion member is different from a refractive index of the adhesive layer.

### Claim 19 (depends on 12)

The method of claim 12, further comprising providing a third diffusion member adhered to a bottom surface of the second diffusion member, the third diffusion member comprising a third convex portion.

### Claim 20

A liquid crystal display, comprising:
a display panel; and
an optical film adhered under the display panel, the optical film comprising:
a polarizer comprising a polyvinyl alcohol (PVA) core layer;
an ultraviolet (UV) adhesive layer under a bottom surface of the PVA core layer;
a diffusion sheet adhered to a bottom surface of the polarizer, the diffusion sheet comprising:
a first diffusion member comprising a first convex portion, the first diffusion member being adhered to the UV adhesive layer such that the UV adhesive layer is between and directly contacts both of the PVA core layer and the first diffusion member;
a second diffusion member adhered to the first diffusion member, the second diffusion member comprising a second convex portion; and
a first adhesive layer between the first diffusion member and the second diffusion member, the first diffusion member and the second diffusion member being adhered together by the first adhesive layer, the first diffusion member and the second diffusion member contacting the same first adhesive layer; and
a prism sheet adhered to a bottom surface of the diffusion sheet, the prism sheet comprising:
a first prism pattern having a plurality of points at a first height; and
a second prism pattern having a plurality of points at a second height less than the first height, at least one of the plurality of points of the second prism pattern being between at least two of the plurality of points of the first prism pattern.

### Claim 21 (depends on 10)

The optical film of claim 10, wherein a convex direction of the first convex portion is opposite to the convex direction of the second convex portion, the convex direction of the third convex portion, and a convex direction of the first prism pattern of the prism sheet.

### Claim 22 (depends on 19)

The method of claim 19, wherein a convex direction of the first convex portion of the first diffusion member is opposite to a convex direction of the second convex portion of the second diffusion member, a convex direction of the third convex portion of the third diffusion member, and a convex direction of the first prism pattern of the prism sheet.

### Claim 23 (depends on 20)

The liquid crystal display of claim 20, further comprising:
a third diffusion member adhered to a bottom surface of the second diffusion member,
wherein a convex direction of the first convex portion of the first diffusion member is opposite to a convex direction of the second convex portion of the second diffusion member, a convex direction of the third convex portion of the third diffusion member, and a convex direction of the first prism pattern of the prism sheet.