# US 10,501,688 B2 · Enhanced wavelength converting structure

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- Number: US 10,501,688 B2
- Document ID: US10501688B2
- Status: Granted
- Kind: B2
- Application number: 14/976,213
- Filed: 2015-12-21
- Published: 2016-06-23
- Granted: 2019-12-10
- Earliest claimed: 2014-12-22
- Assignees: Industrial Technology Research Institute
- Applicants: Industrial Technology Research Institute
- Inventors: Yi-Chun Liu; Pao-Ju Hsieh; Mei-Chih Peng
- Web page: https://patentgrep.com/patent/US10501688B2

## CPC

- C09K 11/703: {with zinc or cadmium}
- C09K 11/565: {with zinc cadmium}
- C09K 11/883: {with zinc or cadmium}
- C09K 19/322: {Compounds containing a naphthalene ring or a completely or partially hydrogenated naphthalene ring}
- G02B 5/3016: {involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528)}
- G02B 6/005: {provided by one optical element, or plurality thereof, placed on the light output side of the light guide}
- C09K 2019/0448: {the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate}
- C09K 2019/2078: {Ph-COO-Ph-COO-Ph}
- C09K 2019/3408: {Five-membered ring with oxygen(s) in fused, bridged or spiro ring systems}
- C09K 2019/521: {Inorganic solid particles}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

The present disclosure provides an enhanced wavelength converting structure. The enhanced wavelength converting structure includes a first crosslinked cholesteric liquid crystal layer and a plurality of first quantum dots dispersed in the first crosslinked cholesteric liquid crystal layer. When a first light is incident into the enhanced wavelength converting structure, the plurality of first quantum dots are excited and emit a second light of a wavelength different from a wavelength of the first light, and the second light is toned up via multiple reflections in the first crosslinked cholesteric liquid crystal layer. The present disclosure further provides a luminescent film and a display backlighting unit.

## Claims

### Claim 1

An enhanced wavelength converting structure, comprising:
a first crosslinked cholesteric liquid crystal layer having a first pitch; and
a plurality of first quantum dots dispersed in the first crosslinked cholesteric liquid crystal layer, wherein when a first light is incident into the enhanced wavelength converting structure, the plurality of first quantum dots are excited by the first light and emit a second light of a wavelength different from a wavelength of the first light, wherein the wavelength of the second light is optically coupled to the first pitch of the first crosslinked cholesteric liquid crystal layer.

### Claim 2 (depends on 1)

The enhanced wavelength converting structure of claim 1, further comprising a substrate, wherein the first crosslinked cholesteric liquid crystal layer is disposed on the substrate.

### Claim 3 (depends on 2)

The enhanced wavelength converting structure of claim 2, wherein the substrate is a barrier layer.

### Claim 4 (depends on 2)

The enhanced wavelength converting structure of claim 2, further comprising a barrier layer, wherein the barrier layer is disposed on the first crosslinked cholesteric liquid crystal layer, and the first crosslinked cholesteric liquid crystal layer is sandwiched between the substrate and the barrier layer.

### Claim 5 (depends on 1)

The enhanced wavelength converting structure of claim 1, wherein the first quantum dots comprising materials selected from a Group II-VI compound, a Group III-V compound or a Group IV-VI compound.

### Claim 6 (depends on 1)

The enhanced wavelength converting structure of claim 1, wherein the first quantum dots having core or core-shell structures capped with ligands.

### Claim 7 (depends on 5)

The enhanced wavelength converting structure of claim 5, wherein the Group II-VI compound is CdSe.

### Claim 8 (depends on 5)

The enhanced wavelength converting structure of claim 5, wherein the Group IV-VI compound is PbS.

### Claim 9 (depends on 5)

The enhanced wavelength converting structure of claim 5, wherein the Group III-V compound is InP.

### Claim 10 (depends on 1)

The enhanced wavelength converting structure of claim 1, wherein a wavelength range of the first light is between 420 nm and 460 nm.

### Claim 11 (depends on 1)

The enhanced wavelength converting structure of claim 1, wherein a wavelength range of the second light is between 520 nm and 580 nm.

### Claim 12 (depends on 1)

The enhanced wavelength converting structure of claim 1, further comprising a plurality of second quantum dots dispersed in the first crosslinked cholesteric liquid crystal layer, the second quantum dots being different from the first quantum dots.

### Claim 13 (depends on 12)

The enhanced wavelength converting structure of claim 12, wherein the second quantum dots comprising materials selected from a Group II-VI compound, a Group III-V compound or a Group IV-VI compound.

### Claim 14 (depends on 12)

The enhanced wavelength converting structure of claim 12, wherein the second quantum dots having core or core-shell structures capped with ligands.

### Claim 15 (depends on 13)

The enhanced wavelength converting structure of claim 13, wherein the Group II-VI compound is CdSe.

### Claim 16 (depends on 13)

The enhanced wavelength converting structure of claim 13, wherein the Group IV-VI compound is PbS.

### Claim 17 (depends on 13)

The enhanced wavelength converting structure of claim 13, wherein the Group III-V compound is InP.

### Claim 18 (depends on 1)

The enhanced wavelength converting structure of claim 1, further comprising:
a second crosslinked cholesteric liquid crystal layer disposed on the first crosslinked cholesteric liquid crystal layer; and
a plurality of second quantum dots dispersed in the second crosslinked cholesteric liquid crystal layer, wherein when the first light is incident into the enhanced wavelength converting structure, the plurality of second quantum dots are excited by the first light and emit a third light of a wavelength different from the wavelength of the first light.

### Claim 19 (depends on 18)

The enhanced wavelength converting structure of claim 18, wherein the second quantum dots comprising materials selected from a Group II-VI compound, a Group III-V compound or a Group IV-VI compound, and the second quantum dots are different from the first quantum dots.

### Claim 20 (depends on 18)

The enhanced wavelength converting structure of claim 18, wherein the second quantum dots having core or core-shell structures capped with ligands.

### Claim 21 (depends on 19)

The enhanced wavelength converting structure of claim 19, wherein the Group II-VI compound is CdSe.

### Claim 22 (depends on 19)

The enhanced wavelength converting structure of claim 19, wherein the Group IV-VI compound is PbS.

### Claim 23 (depends on 19)

The enhanced wavelength converting structure of claim 19, wherein the Group III-V compound is InP.

### Claim 24 (depends on 18)

The enhanced wavelength converting structure of claim 18, wherein a wavelength range of the third light is between 600 nm and 680 nm.

### Claim 25 (depends on 18)

The enhanced wavelength converting structure of claim 18, wherein a pitch of the second crosslinked cholesteric liquid crystal layer is different from a pitch of the first crosslinked cholesteric liquid crystal layer.

### Claim 26 (depends on 1)

The enhanced wavelength converting structure of claim 1, wherein the first crosslinked cholesteric liquid crystal layer includes a mixture of a crosslinked liquid crystal and an optically active substance.

### Claim 27 (depends on 1)

A luminescent film, comprising:
the enhanced wavelength converting structure of claim 1; and
at least one optical film disposed on a surface of the enhanced wavelength converting structure.

### Claim 28 (depends on 27)

The luminescent film of claim 27, wherein the optical film is a prism brightness enhancement film, a cholesteric liquid crystal reflective polarizer, a multilayer reflective polarizer, or a diffuser film.

### Claim 29 (depends on 1)

A display backlighting unit, comprising:
at least one primary light source emitting primary light;
a light guide panel (LGP) optically coupled to the at least one primary light source and configured to uniformly transmit the primary light through the LGP; and
the enhanced wavelength converting structure of claim 1 disposed over the LGP.