# US 10,502,989 B2 · Display panel and display device

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- Number: US 10,502,989 B2
- Document ID: US10502989B2
- Status: Granted
- Kind: B2
- Application number: 15/737,007
- Filed: 2017-07-31
- Published: 2018-12-20
- Granted: 2019-12-10
- Earliest claimed: 2016-10-28
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Jifeng Tan; Wei Wang; Yafeng Yang; Xiaochuan Chen; Jian Gao; Can Wang; Can Zhang; Xinli Ma; Xiandong Meng; Xianqin Meng; Dacheng Zhang
- Web page: https://patentgrep.com/patent/US10502989B2

## CPC

- G02F 1/1326: {Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides}
- G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
- G02F 1/133504: {Diffusing, scattering, diffracting elements (associated to illuminating devices G02F1/133606)}
- G02F 1/133553: {Reflecting elements (associated to illuminating devices G02F1/133605)}
- G02F 1/133615: {Edge-illuminating devices, i.e. illuminating from the side}
- G02F 1/13363: Birefringent elements, e.g. for optical compensation
- G02F 1/1343: Electrodes {(reflective electrodes G02F1/133553)}
- G02F 1/133567: {on the back side}
- G02F 2201/30: grating
- G02F 2201/307: Reflective grating, i.e. Bragg grating
- 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

A display panel and a display device are disclosed and belong to the field of display technology. The display panel comprises a first substrate and a second substrate opposite to each other, and a liquid crystal layer, a first electrode, as second electrode, a waveguide layer and a grating layer between the first and second substrates; wherein the waveguide layer is on a side of the liquid crystal layer proximal to the first substrate; and the grating layer is in contact with the liquid crystal layer; the first electrode and the second electrode are configured to adjust a refractive index of the liquid crystal layer by changing voltages applied thereto; and a coupling efficiency at which light is coupled out of the waveguide layer is determined according to a difference between a refractive index of the grating layer and the refractive index of the liquid crystal layer.

## Claims

### Claim 1

A display panel, comprising a first substrate and a second substrate opposite to each other, and a liquid crystal layer, a first electrode, as second electrode, a waveguide layer and a grating layer that are between the first substrate and the second substrate; wherein,
the waveguide layer is on a side of the liquid crystal layer proximal to the first substrate; and the grating layer is in contact with the liquid crystal layer;
the first electrode and the second electrode are configured to adjust a refractive index of the liquid crystal layer by changing voltages applied thereto; and
a coupling efficiency at which light is coupled out of the waveguide layer is determined according to a difference between a refractive index of the grating layer and the refractive index of the liquid crystal layer,
wherein the first electrode is on a side of the waveguide layer proximal to the first substrate; the grating layer is on the side of the waveguide layer away from the first electrode; the liquid crystal layer is on a side of the grating layer away from the waveguide layer; and the second electrode is on a side of the second substrate proximal to the liquid crystal layer, and a refractive index of the waveguide layer is larger than a refractive index of the first electrode, and the refractive index of the first electrode is larger than or equal to the refractive index of the grating layer.

### Claim 2 (depends on 1)

The display panel of claim 1, wherein the grating layer is on a side of the liquid crystal layer proximal to the first substrate.

### Claim 3 (depends on 1)

The display panel of claim 1, wherein the first electrode and the second electrode are on one side of the liquid crystal layer.

### Claim 4 (depends on 1)

The display panel of claim 1, wherein the first electrode and the second electrode are on different sides of the liquid crystal layer.

### Claim 5 (depends on 1)

The display panel of claim 1, wherein the refractive index of the grating layer ranges from an ordinary refractive index no of the liquid crystal layer to an extraordinary refractive index ne of the liquid crystal layer.

### Claim 6 (depends on 5)

The display panel of claim 5, wherein a material of the liquid crystal layer comprises a polymer dispersed liquid crystal.

### Claim 7 (depends on 5)

The display panel of claim 5, wherein a material of the liquid crystal layer comprises a polymer network liquid crystal.

### Claim 8 (depends on 1)

The display panel of claim 1, wherein the grating layer comprises grating structures arranged at intervals, the liquid crystal layer covers the grating layer and fills in a gap between the grating structures, and a thickness of the liquid crystal layer is larger than a thickness of the grating layer.

### Claim 9 (depends on 8)

The display panel of claim 8, wherein the display panel comprises a plurality of pixel units, and a period of the grating structure in each of the pixel units corresponds to an emergent angle of light of a specific wavelength.

### Claim 10 (depends on 8)

The display panel of claim 8, wherein a material of the liquid crystal layer comprises a polymer dispersed liquid crystal.

### Claim 11 (depends on 8)

The display panel of claim 8, wherein a material of the liquid crystal layer comprises a polymer network liquid crystal.

### Claim 12 (depends on 9)

The display panel of claim 9, wherein a material of the liquid crystal layer comprises a polymer dispersed liquid crystal.

### Claim 13 (depends on 1)

The display panel of claim 1, wherein a material of the liquid crystal layer comprises a polymer dispersed liquid crystal.

### Claim 14 (depends on 1)

A display device, comprising a backlight and the display panel according to claim 1.

### Claim 15

The display device of clam 14, wherein the backlight is an edge type backlight configured to provide collimated light.

### Claim 16

The display device of clam 15, further comprising a light-shielding layer on a side of the display panel away from the backlight.

### Claim 17 (depends on 1)

The display panel of claim 1, wherein a material of the liquid crystal layer comprises a polymer network liquid crystal.