Reflective display device

• US 10,476,034 B2
• Filed: 05/27/2016
• Issued: 11/12/2019
• Est. Priority Date: 12/15/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Im, Jonghyeok, Kim, SeJune
• Primary Examiner(s): Gauthier, Steven B
• Application Number:
  US15/167,692
• Publication Number:
  US 20170170431A1
• Time in Patent Office: 1,264 Days
• Field of Search: None
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H10K 2102/00 Constructional details relating to the organic devices covered by this subclass
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/814 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

A reflective display device provided with an optical layer which is capable of improving adhesion between a substrate and a reflective layer and controlling a color of reflected light is disclosed. The reflective display device includes first and second substrates facing each other, each of which includes a display area and a reflective area; a display element provided in the display area; a reflective layer provided in the reflective area and arranged on one surface of the second substrate to reflect incident light; and an optical layer arranged between the second substrate and the reflective layer.

Claims

1. A display device comprising:

a first substrate;

a second substrate having a first surface facing the first substrate, the first substrate and the second substrate divided into a plurality of pixel regions, wherein each pixel region is divided into one among a plurality of display areas and one among a plurality of reflective areas;

a plurality of thin film transistors, the plurality of thin film transistors on the first substrate in the plurality of display areas;

a passivation layer in the plurality of display areas and the plurality of reflective areas;

a planarization layer on the passivation layer in the plurality of display areas;

a plurality of display elements between the first substrate and the second substrate, the plurality of display elements configured to be driven by the plurality of thin film transistors, the plurality of display elements comprising;

a plurality of color filters on the first surface of the second substrate in the plurality of display areas;

anode electrodes on the planarization layers in the plurality of display areas;

organic light emitting layers on the anode electrodes; and

cathode electrodes on the organic light emitting layers,

a plurality of optical layers, the plurality of optical layers on the first surface of the second substrate in the plurality of reflective areas, the plurality of optical layers configured to produce light of a first color from light of a second color incident upon the plurality of optical layers;

a plurality of reflective layers, the plurality of reflective layers on the plurality of optical layers and configured to reflect light passing through the plurality of optical layers towards the plurality of optical layers; and

bank layers defining the plurality of display areas on the first substrate,

wherein each of the plurality of thin film transistors, each of the plurality of color filters, and each of the bank layers are disposed within a corresponding display area of the plurality of display areas,

wherein the plurality of color filters contact a side surface of the plurality of optical layers and a side surface of the plurality of reflective layers, and cover at least a surface of the plurality of reflective layers facing the first substrate,

wherein in each of the plurality of display areas, each of the plurality of color filters faces one of the cathode electrodes, and in each of the plurality of reflective areas, each of the plurality of reflective layers faces the passivation layer, and

wherein the anode electrodes, the organic light emitting layers, and the cathode electrodes are disposed on the planarization layer in each of the plurality of display areas.

2. The display device of claim 1, wherein a display area and a reflective area adjacent to the display area define a pixel region of the plurality of pixel regions.

3. The display device of claim 1, wherein an adhesion between the plurality of optical layers and the first surface of the second substrate is stronger than an adhesion between the plurality of reflective layers and the first surface of the second substrate.

4. The display device of claim 1, wherein the plurality of optical layers are made of a transparent conductive oxide (TCO) material.

5. The display device of claim 1, wherein when the second color is a white color, the first color is a blue color when a thickness of the plurality of optical layers is between 55 nm and 100 nm, the first color is a red color when a thickness of the plurality of optical layers is between 175 nm and 200 nm, and the first color is a green color when a thickness of the plurality of optical layers is between 225 and 275 nm.

6. The display device of claim 1, wherein the plurality of reflective layers are made of at least one of Ag, Ag-alloys, Al, and AlNd.

7. The display device of claim 1, wherein a first subset of optical layers has a first thickness that is different from a second thickness of a second subset of optical layers.

8. The display device of claim 1, wherein an area of the plurality of reflective areas is larger than an area of the plurality of display areas.

9. The display device of claim 1, wherein the plurality of display elements comprise:

the plurality of color filters;

the passivation layer;

the planarization layers;

the anode electrodes on the planarization layers in the plurality of display areas;

auxiliary electrodes on the planarization layers, the auxiliary electrodes and the anode electrodes separated by a distance;

the bank layers partially covering the anode electrodes and the auxiliary electrodes, the bank layers exposing portions of the anode electrodes and portions of the auxiliary electrodes;

barriers on the exposed portions of the auxiliary electrodes, the barriers separated from the bank layers and at least a portion of the barriers having a width larger than a width of the exposed portions of the auxiliary electrodes;

the organic light emitting layers on the exposed portions of the anode electrodes and on at least a portion of a top surface of the barriers; and

the cathode electrodes on the organic light emitting layers and in contact with the exposed portions of the auxiliary electrodes.

10. The display device of claim 1, wherein the plurality of optical layers are formed of at least one of indium tin oxide (ITO) or indium zinc oxide (IZO).

11. A display device comprising:

a plurality of pixel regions, each of the pixel regions comprising;

a display area comprising;

a first portion of a first substrate,

a first portion of a second substrate aligned with the first portion of the first substrate,

a thin film transistor on the first portion of the first substrate,

a first portion of a passivation layer in the display area;

a planarization layer on the first portion of the passivation layer in the display area; and

a display element between the first portion of the first substrate and the first portion of the second substrate, the display element configured to be driven by the thin film transistor, the display element comprising;

a color filter on a first surface of the first portion of the second substrate facing the first substrate,

a bank layer defining the display area;

an anode electrode on the planarization layer in the display area;

an organic light emitting layer on the anode electrode; and

a cathode electrode on the organic light emitting layer; and

a reflective area adjacent to the display area and comprising;

a second portion of the first substrate,

a second portion of the second substrate aligned with the second portion of the first substrate,

a second portion of the passivation layer in the reflective area,

an optical layer on a second surface of the second portion of the second substrate facing the first substrate, the optical layer configured to produce light of a first color from light of a second color incident upon the optical layer, and

a reflective layer on the optical layer, the reflective layer configured to reflect light passing through the optical layer towards the optical layer,

wherein the color filter contacts a side surface of the optical layer and a side surface of the reflective layer, and covers at least a surface of the reflective layer facing the first substrate,

wherein in the display area, the color filter faces the cathode electrode, and in the reflective area, the reflective layer faces the second portion of the passivation layer, and

wherein the anode electrode, the organic light emitting layer, and the cathode electrode are disposed on the planarization layer in the display area.

12. The display device of claim 11, wherein an adhesion between the optical layer and the first surface of the second substrate is stronger than an adhesion between the reflective layer and the first surface of the second substrate.

13. The display device of claim 11, wherein the optical layer is made of a transparent conductive oxide (TCO) material.

14. The display device of claim 11, wherein when the second color is a white color, the first color is a blue color when a thickness of the optical layer is between 55 nm and 100 nm, the first color is a red color when a thickness of the optical layer is between 175 nm and 200 nm, and the first color is a green color when a thickness of the optical layer is between 225 and 275 nm.

15. The display device of claim 11, wherein the reflective layer is made of at least one of Ag, Ag-alloys, Al, and AlNd.

16. The display device of claim 11, wherein optical layers in a first subset of pixel regions have a first thickness that is different from a second thickness of optical layers in a second subset of pixel regions.

17. The display device of claim 11, wherein an area of the reflective area is larger than an area of the display area.

18. The display device of claim 11, wherein the optical layer is formed of at least one of indium tin oxide (ITO) or indium zinc oxide (IZO).