Organic electroluminescent display device and method for producing same

• US 10,644,256 B2
• Filed: 12/25/2017
• Issued: 05/05/2020
• Est. Priority Date: 12/25/2017
• Status: Active Grant

• Current Assignee: Sakai Display Products Corporation (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sakai Display Products Corporation (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kishimoto, Katsuhiko
• Primary Examiner(s): Withers, Grant S
• Application Number:
  US16/079,444
• Publication Number:
  US 20190363281A1
• Time in Patent Office: 862 Days
• Field of Search: None
• CPC Class Codes: G09F 9/30 in which the desired character or characters are formed by combining individual elements panels comprising a number of electrodes in a single cell controlling light arriving from an independent light source, e.g. electro-optical or magneto-optical cell, G02F1/00
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

An organic EL display device (100) includes an element substrate including a substrate, a plurality of organic EL elements supported by the substrate and respectively located in the plurality of pixels, and a bank layer (48) defining each of the plurality of pixels; and a thin film encapsulation structure (10) covering the plurality of pixels. The bank layer has an inclining surface enclosing each of the plurality of pixels. The thin film encapsulation structure includes a first inorganic barrier layer (12), an organic barrier layer (14) including a plurality of solid portions in contact with a top surface of the first inorganic barrier layer and distributed discretely, and a second inorganic barrier layer (16) in contact with the top surface of the first inorganic barrier layer and top surfaces of the plurality of solid portions of the organic barrier layer. The plurality of solid portions include pixel periphery solid portions (14a) each extending, on the first inorganic barrier layer, from a portion on the inclining surface to a peripheral area in the corresponding pixel of the plurality of pixels, the pixel periphery solid portions each extending along the entirety of a circumference of the pixel. A refractive index n0 of the organic barrier layer is smaller than a refractive index n1 of the second inorganic barrier layer, and the top surfaces of the pixel periphery solid portions each have an inclination angle θa larger than, or equal to, 20 degrees.

Claims

1. An organic EL display device including a plurality of pixels, comprising:

an element substrate including a substrate, a plurality of organic EL elements supported by the substrate and respectively located in the plurality of pixels, and a bank layer defining each of the plurality of pixels; and

a thin film encapsulation structure covering the plurality of pixels,

wherein the bank layer has an inclining surface enclosing each of the plurality of pixels,

wherein the thin film encapsulation structure includes a first inorganic barrier layer, an organic barrier layer including a plurality of solid portions in contact with a top surface of the first inorganic barrier layer and distributed discretely, and a second inorganic barrier layer in contact with the top surface of the first inorganic barrier layer and top surfaces of the plurality of solid portions of the organic barrier layer,

wherein the plurality of solid portions include pixel periphery solid portions each extending, on the first inorganic barrier layer, from a portion on the inclining surface to a peripheral area in a corresponding pixel of the plurality of pixels, the pixel periphery solid portions each extending along the entirety of a circumference of the pixel, and

wherein a refractive index n0 of the organic barrier layer is smaller than a refractive index n1 of the second inorganic barrier layer, and the top surfaces of the pixel periphery solid portions each have an inclination angle θ

a larger than, or equal to, 20 degrees, and

wherein a refractive index of the first inorganic barrier layer is equal to the refractive index n1 of the second inorganic barrier layer.

2. The organic EL display device of claim 1, wherein the inclination angle θ

a of each of the top surfaces of the pixel periphery solid portions is smaller than, or equal to, 40 degrees.

3. The organic EL display device of claim 1, wherein the inclining surface of the bank layer has an inclination angle θ

b of 20 degrees or larger and 60 degrees or smaller.

4. The organic EL display device of claim 1, wherein the refractive index n1 of the second inorganic barrier layer and the refractive index n0 of the organic barrier layer have a difference (Δ

n1=n1−

n0) that is larger than, or equal to, 0.25.

5. The organic EL display device of claim 1, wherein the refractive index n1 of the second inorganic barrier layer is 1.75 or larger and 1.90 or smaller.

6. The organic EL display device of claim 1, wherein the pixel periphery solid portions each have a recessed surface.

7. A method for producing the organic EL display device, the organic EL display device including a plurality of pixels, comprising:

an element substrate including a substrate, a plurality of organic EL elements supported by the substrate and respectively located in the plurality of pixels, and a bank layer defining each of the plurality of pixels; and

a thin film encapsulation structure covering the plurality of pixels,

wherein the bank layer has an inclining surface enclosing each of the plurality of pixels,

wherein the thin film encapsulation structure includes a first inorganic barrier layer, an organic barrier layer including a plurality of solid portions in contact with a top surface of the first inorganic barrier layer and distributed discretely, and a second inorganic barrier layer in contact with the top surface of the first inorganic barrier layer and top surfaces of the plurality of solid portions of the organic barrier layer,

wherein the plurality of solid portions include pixel periphery solid portions each extending, on the first inorganic barrier layer, from a portion on the inclining surface to a peripheral area in a corresponding pixel of the plurality of pixels, the pixel periphery solid portions each extending along the entirety of a circumference of the pixel, and

wherein a refractive index n0 of the organic barrier layer is smaller than a refractive index n1 of the second inorganic barrier layer, and the top surfaces of the pixel periphery solid portions each have an inclination angle θ

a larger than, or equal to, 20 degrees, and

wherein a refractive index of the first inorganic barrier layer is equal to the refractive index n1 of the second inorganic barrier layer,

wherein the step of forming the thin film encapsulation structure includes the steps of;

preparing the element substrate having the first inorganic barrier layer formed thereon in a chamber;

supplying a vapor-like or mist-like photocurable resin into the chamber;

condensing the photocurable resin on the first inorganic barrier layer to form a liquid film;

irradiating the liquid film of the photocurable resin with light to form a photocurable resin layer; and

partially ashing the photocurable resin layer to form the organic barrier layer.

8. The method of claim 7, wherein the inclination angle θ

a of each of the top surfaces of the pixel periphery solid portions is smaller than, or equal to, 40 degrees.

9. The method of claim 7, wherein the inclining surface of the bank layer has an inclination angle θ

b of 20 degrees or larger and 60 degrees or smaller.

10. The method of claim 7, wherein the refractive index n1 of the second inorganic barrier layer and the refractive index n0 of the organic barrier layer have a difference (Δ

n1=n1−

n0) that is larger than, or equal to, 0.25.

11. The method of claim 7, wherein the refractive index n1 of the second inorganic barrier layer is 1.75 or larger and 1.90 or smaller.

12. The method of claim 7, wherein a refractive index of the first inorganic barrier layer is equal to the refractive index n1 of the second inorganic barrier layer.

13. The method of claim 7, wherein the pixel periphery solid portions each have a recessed surface.