# US 11,307,332 B2 · Diffusion sheet, laminated prism sheet, and laminated optical sheet

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- Number: US 11,307,332 B2
- Document ID: US11307332B2
- Status: Granted
- Kind: B2
- Application number: 16/689,366
- Filed: 2019-11-20
- Published: 2020-03-19
- Granted: 2022-04-19
- Earliest claimed: 2014-12-05
- Assignees: Suntechopt Co., Ltd.
- Applicants: Suntechopt Co., Ltd.
- Inventors: Yukio Shimamura; Kiyoshi Sakai
- Web page: https://patentgrep.com/patent/US11307332B2

## CPC

- G02B 5/0231: {the surface having microprismatic or micropyramidal shape (macroscopic prism arrays G02B5/045)}
- G02B 5/0215: {the surface having a regular structure}
- G02B 5/0278: {used in transmission}
- G02B 6/0051: {Diffusing sheet or layer}
- G02B 6/0053: {Prismatic sheet or layer; Brightness enhancement element, sheet or layer}
- G02B 5/0221: {the surface having an irregular structure (G02B5/0226 takes precedence)}
- G02B 5/0268: {characterized by the fabrication or manufacturing method}
- G02B 6/0056: {for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements}
- G02B 27/283: {used for beam splitting or combining}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Provided is a diffusion sheet having a function for preventing warping, and having excellent optical and diffusion characteristics. A diffusion sheet 1 has a minute roughness pattern formed on the surface thereof, the pattern configured such that first protrusions 3a having a first height and second protrusions 3b having a second height lower than the first height are disposed in parallel. A portion of the first protrusions 3a is bonded to a bonding layer on the rear surface of an upper-layer sheet laminated on the surface of a diffusion sheet 2, and the second protrusions 3b are not bonded to said bonding layer. The following relationships are satisfied: h1:h2=1:0.5-0.1, and w1:w2=1:1.0-0.1, where h1 is the height of the first protrusions 3a, w1 is the width of the first protrusions 3a, h2 is the height of the second protrusions 3b, and w2 is the width of the second protrusions 3b.

## Claims

### Claim 1

A laminated sheet, comprising:
a diffusion sheet having a diffusion sheet back surface and a diffusion sheet front surface, a diffusion sheet back surface diffusion layer laminated to the diffusion sheet back surface, the diffusion sheet back surface diffusion layer including convex portions of random diffusion heights, a diffusion sheet front surface diffusion layer laminated to the diffusion sheet front surface, the diffusion sheet front surface diffusion layer having convex portions of at least a first diffusion height and a second diffusion height;
a lower prism sheet having a lower prism sheet back surface and a lower prism sheet front surface, a lower prism sheet adhesion layer adhered to the lower prism sheet back surface, at least a portion of the diffusion sheet front surface diffusion layer convex portion of the first diffusion height adhered to the lower prism sheet adhesion layer, at least a portion of the diffusion sheet front surface diffusion layer convex portion of the second diffusion height not adhered to the lower prism sheet adhesion layer, a lower prism sheet prism layer laminated to the lower prism sheet front surface, the lower prism sheet prism layer having convex portions of at least a first prism height and a second prism height;
an upper prism sheet having an upper prism sheet back surface and an upper prism sheet front surface, an upper prism sheet adhesion layer adhered to the upper prism sheet back surface, at least a portion of the lower prism sheet prism layer convex portion of the first prism height adhered to the upper prism sheet adhesion layer, at least a portion of the lower prism sheet prism layer convex portion of the second prism height not adhered to the upper prism sheet adhesion layer, an upper prism sheet prism layer laminated to the upper prism sheet front surface, the upper prism sheet prism layer having convex portions.

### Claim 2 (depends on 1)

The laminated sheet as set forth in claim 1, wherein a refractive index of the lower prism sheet adhesion layer nb and a refractive index of the diffusion sheet front surface diffusion layer nm satisfy |nb−nm|>0.1.

### Claim 3 (depends on 1)

The laminated sheet as set forth in claim 1, wherein at least some of a plurality of second diffusion heights are 0.6 to 0.9 times the first diffusion height.

### Claim 4 (depends on 1)

The laminated sheet as set forth in claim 1, wherein the lower prism sheet prism layer convex portion includes a first prism column, the first prism column has first prism height m1 and has a first prism column width k1, the lower prism sheet prism layer convex portion includes a second prism column, the second prism column has second prism height m2 and has a second prism width k2, and wherein relationships m1:m2=1:x and k1:k2=1:1 are satisfied, with x being in a range 0.6˜0.9.

### Claim 5 (depends on 1)

The laminated sheet as set forth in claim 1, wherein a column of the lower prism sheet prism layer convex portions has a same vertex shape or a same cross-section shape as a column of the upper prism sheet prism layer convex portions.

### Claim 6 (depends on 1)

The laminated sheet as set forth in claim 1, wherein a vertex portion of a column of the lower prism sheet prism layer convex portions has a curved surface.

### Claim 7 (depends on 1)

The laminated sheet as set forth in claim 1, wherein a thickness of at least one of the following is 0.5˜5 μm: the lower prism sheet adhesion layer, or the upper prism sheet adhesion layer.

### Claim 8 (depends on 1)

The laminated sheet as set forth in claim 1, wherein the random diffusion heights are disposed periodically on the diffusion sheet back surface diffusion layer.

### Claim 9 (depends on 1)

The laminated sheet as set forth in claim 1, wherein the random diffusion heights are disposed randomly on the diffusion sheet back surface diffusion layer.

### Claim 10 (depends on 1)

The laminated sheet as set forth in claim 1, wherein at least a portion of the lower prism sheet prism layer convex portions is disposed on the lower prism sheet prism layer in a periodical parallel arrangement.

### Claim 11 (depends on 1)

The laminated sheet as set forth in claim 1, wherein at least a portion of the lower prism sheet prism layer convex portions is disposed on the lower prism sheet prism layer in a parallel arrangement with random intervals.