# US 10,371,875 B2 · Display device having a color conversion layer

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- Number: US 10,371,875 B2
- Document ID: US10371875B2
- Status: Granted
- Kind: B2
- Application number: 14/717,431
- Filed: 2015-05-20
- Published: 2016-03-03
- Granted: 2019-08-06
- Earliest claimed: 2014-09-03
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Dong Uk Kim; Min Ki Nam; Hae Il Park; Jun Han Lee
- Web page: https://patentgrep.com/patent/US10371875B2

## CPC

- G02B 5/0242: {by means of dispersed particles}
- G02B 1/005: {made of photonic crystals or photonic band gap materials (photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295)}
- G02F 1/133602: {Direct backlight}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- G02F 1/133603: {with LEDs}
- G02F 1/133614: {using photoluminescence, e.g. phosphors illuminated by UV or blue light}
- G02F 2202/32: Photonic crystals
- Y10S 977/774: Exhibiting three-dimensional carrier confinement, e.g. quantum dots
- 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
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A display device may include a substrate and a plurality of color conversion units on the substrate. Each of the plurality of color conversion units may include a photonic crystal layer having at least two layers having different refractive indices alternately stacked, and a wavelength shifter dispersed in at least one of the at least two layers.

## Claims

### Claim 1

A display device, comprising:
a substrate; and
a plurality of color conversion units on the substrate,
wherein the plurality of color conversion units includes a green color conversion unit to absorb blue light and emit green light, and a red color conversion unit to, absorb blue light and emit red light;
wherein each of the green color conversion unit and the red color conversion unit includes:
a photonic crystal layer including photonic crystals having periodicity in a single direction in which two layers having different refractive indices alternately stacked, the two layers including a first layer having a first refractive index and a second layer having a second refractive index; and
a wavelength shifter dispersed in both the first and second layers
when the first layer has a thickness of d1 and a refractive index of n1, and a wavelength of light emitted from the photonic crystal layer is λ, the following equation is satisfied: n1×d1=m1×(λ/2), where m1 is a natural number; and
when the second layer has a thickness of d2 and a refractive index of n2, and a wavelength of light emitted from the photonic crystal layer is λ, the following equation is satisfied: n2×d2=m2×(λ/2), where m2 is a natural number.

### Claim 2 (depends on 1)

The display device as claimed in claim 1, further comprising a black matrix to partition the green color conversion unit and the red color conversion unit into pixels.

### Claim 3 (depends on 1)

The display device as claimed in claim 1, wherein the wavelength shifter is a phosphor or a quantum dot (QD).

### Claim 4 (depends on 1)

The display device as claimed in claim 1, wherein the two layers include:
the first layer has the first refractive index in a range of 1.3 to 1.9; and
the second layer has the second refractive index in a range of 1.5 to 2.5.

### Claim 5 (depends on 1)

The display device as claimed in claim 1, further includes a light scatterer dispersed in at least one of the two layers.

### Claim 6 (depends on 5)

The display device as claimed in claim 5, wherein the light scatterer is randomly dispersed.

### Claim 7 (depends on 1)

The display device as claimed in claim 1, further comprising a thin film transistor layer on the color conversion units.

### Claim 8 (depends on 1)

The display device as claimed in claim 1, wherein each of the pluraltiy of color conversion units is designed for a particular wavelength range and each layer therein has a refractive index n and thickness d that satisifies the following equation:
λ=2(n×d)/m
where m is natural number and λ is within the particular wavelength range.

### Claim 9 (depends on 1)

The display device as claimed in claim 1, wherein the wavelength shifter is dispersed in both of the two layers.

### Claim 10

A liquid crystal display, comprising:
a first substrate;
a plurality of color conversion units on the first substrate;
a second substrate opposite the first substrate; and
a liquid crystal layer between the first and second substrates,
wherein the plurality of color conversion units includes a green color conversion unit to absorb blue light and emit green light; and a red color conversion unit to absorb blue light and emit red light;
wherein each of the green color conversion unit and the red color conversion unit includes:
a photonic crystal layer including photonic crystals having periodicity in a single direction in which two layers having different refractive indices alternately stacked, the two layers including a first layer having a first refractive index and a second layer having a second refractive index; and
a wavelength shifter dispersed in both the first and layers,
when the first layer has a thickness of d1 and a refractive index of n1, and a wavelength of light emitted from the photonic crystal layer is λ, the following equation is satisfied: n1×d1=m1×(λ/2), where m1 is a natural number; and
when the second layer has a thickness of d2 and a refractive index of n2, and a wavelength of light emitted from the photonic crystal layer is λ, the following equation is satisfied: n2×d2=m2×(λ/2), where m2 is a natural number.

### Claim 11 (depends on 10)

The liquid crystal display as claimed in claim 10, further comprising a black matrix on the first substrate, the black matrix to partition the green color conversion unit and the red color conversion unit into pixels.

### Claim 12 (depends on 10)

The liquid crystal display as claimed in claim 10, wherein the wavelength shifter is a phosphor or a quantum dot (QD).

### Claim 13 (depends on 10)

The liquid crystal display as claimed in claim 10, wherein the two layers include:
the first layer has the first refractive index in a range of 1.3 to 1.9; and
the second layer has the second refractive index in a range of 1.5 to 2.5.

### Claim 14 (depends on 10)

The liquid crystal display as claimed in claim 10, further comprising a light scatterer dispersed in the photonic crystal layer.

### Claim 15 (depends on 10)

The liquid crystal display as claimed in claim 10, further comprising a thin film transistor layer on the color conversion units.

### Claim 16 (depends on 10)

The liquid crystal display as claimed in claim 10, wherein each of the pluraltiy of color conversion units is designed for a particular wavelength range and each layer therein has a refractive index n and thickness d that satisifies the following equation:
λ=2(n×d)/m
where m is natural number and λ is within the particular wavelength range.

### Claim 17 (depends on 10)

The liquid crystal display as claimed in claim 10, wherein the wavelength shifter is dispersed in both of the two layers.