OLED Encapsulating Film Gradient Thickness and Density

Solution Overview

Problem

Organic light emitting diode (OLED) display devices are prone to degradation due to moisture and oxygen exposure, with conventional encapsulating materials failing to effectively prevent side permeation, leading to reduced lifespan and complex manufacturing processes.

Innovation Solution

A film encapsulating structure with a temperature gradient is implemented, where the density and thickness of the encapsulating film increase from the center to the edge, using a combination of inorganic and organic layers deposited via methods like sputter, CVD, or ALD, with a hot wire mask to control substrate temperature and deposition rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional encapsulating materials are used with uniform thickness, then the manufacturing process is simple, but side waterproof property is poor and moisture permeation occurs

Engineering Contradiction:

Improveside waterproof propertyVSAvoidencapsulating film structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulating film is designed with non-uniform thickness where the thickness increases from the center toward the edge of the substrate. This local variation in thickness provides enhanced waterproofing at the edges where moisture penetration is most likely to occur, while maintaining a simpler overall structure compared to multi-layer conventional designs.

Inventive Principle:

Principle #3Local quality

2Reliability

If uniform density encapsulating film is used, then the deposition process is simple, but edge protection against moisture is insufficient

Engineering Contradiction:

Improvemoisture barrier performanceVSAvoidfilm density control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The deposition process parameters are varied across the substrate surface to create a density gradient in the encapsulating film. The film density increases from the center toward the edge, providing enhanced moisture barrier performance at the edges. This is achieved by controlling deposition conditions such as substrate temperature or deposition rate as functions of position.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If conventional uniform encapsulation is used, then manufacturing is straightforward, but lifespan is reduced due to moisture and oxygen degradation

Engineering Contradiction:

ImproveOLED lifespanVSAvoidencapsulating film configuration

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The encapsulating film is designed with non-uniform thickness where the thickness increases from the center toward the edge of the substrate. This local variation in thickness provides enhanced waterproofing at the edges where moisture penetration is most likely to occur, while maintaining a simpler overall structure compared to multi-layer conventional designs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The encapsulating film comprises alternating inorganic and organic layers that work together to provide superior barrier properties against both moisture and oxygen. This composite structure leverages the complementary characteristics of different materials to extend OLED lifespan.

Inventive Principle:

Principle #40Composite materials

4Reliability

If edge-focused encapsulation is implemented, then side waterproof property improves, but manufacturing complexity increases

Engineering Contradiction:

Improveside waterproof propertyVSAvoiddeposition process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The deposition process parameters are varied across the substrate surface to create a density gradient in the encapsulating film. The film density increases from the center toward the edge, providing enhanced moisture barrier performance at the edges. This is achieved by controlling deposition conditions such as substrate temperature or deposition rate as functions of position.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces moisture and oxygen permeation through the side interface, enhancing the waterproof properties and prolonging the lifespan of OLED display devices while simplifying the manufacturing process.

Implementation Method 1

a temperature gradient formed on a substrate, wherein a deposition rate varies according to the temperature gradient

Methodology Applied

Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

applying an encapsulating film material to the substrate where the temperature gradient is formed

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS8169132B2Organic light emitting diode display device and method of manufacturing the same

Publication Date: 2012.05.01 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting diode (OLED) display device and a method of manufacturing the same is disclosed. In one embodiment, the OLED device includes a substrate; a display unit formed on a display area of the substrate; and an encapsulating film covering i) the display unit and ii) a non-display area surrounding the display area, wherein the density and thickness of the encapsulating film increase in a direction from a center portion of the encapsulating film to an edge portion of the encapsulating film.