Pixel Defining Layer Non-Planar Side Surface Inkjet Printing

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Solution Overview

Problem

Self-luminous display panels face issues with uneven film formation and electrode defects due to the coffee ring effect and acute angles in traditional pixel defining layers, affecting luminance and display performance.

Innovation Solution

A pixel defining layer with non-planar side surfaces, such as convex or cambered surfaces, is used, forming a capillary structure that aids even spreading of organic light-emitting material solutions during inkjet printing, and includes lyophobic and lyophilic material layers to control solution distribution and prevent electrode damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional planar pixel defining layers are used, then manufacturing is simple, but film formation is uneven and electrode defects occur due to the coffee ring effect and acute angles

Engineering Contradiction:

Improvefilm formation evennessVSAvoidpixel defining layer structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pixel defining layer uses a convex side surface instead of a planar surface. This curved structure prevents the coffee ring effect by eliminating acute angles where solution tends to accumulate, enabling uniform film formation across the sub-pixel region while maintaining manufacturing feasibility through standard fabrication processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The pixel defining layer incorporates different material properties in different regions: a lyophobic material layer on the outer side to repel solution and prevent climbing, and a lyophilic material layer on the inner side to attract and evenly distribute the solution. This local differentiation of material properties solves the film formation uniformity issue without requiring complex overall structure changes.

Inventive Principle:

Principle #3Local quality

2Reliability

If planar pixel defining structures are used, then manufacturing is easy, but solution climbing occurs and electrode damage happens due to acute angles

Engineering Contradiction:

Improveelectrode defect reductionVSAvoidpixel defining layer fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The convex side surface of the pixel defining layer eliminates acute angles that cause solution to climb and accumulate. The curved geometry naturally directs solution flow away from the electrode edges, preventing electrode damage and improving reliability without significantly complicating the manufacturing process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The lyophobic material layer is positioned on the outer side of the pixel defining structure to preemptively repel the solution before it can climb and reach the electrode. This preliminary protective action prevents solution accumulation and electrode damage before they can occur, enhancing reliability while using standard material deposition techniques.

Inventive Principle:

Principle #9Preliminary anti-action

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

The solution improves the evenness of film formation and reduces electrode defects, enhancing the display performance and luminance of self-luminous display panels by reducing solution climbing and ensuring flatness within sub-pixel regions.

Implementation Method 1

the pixel defining structure has a first bottom surface and a second bottom surface opposite each other, and a side surface between the first bottom surface and the second bottom surface, the side surface being non-planar

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the pixel defining structure comprises a lyophobic material layer repelling liquid

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 3

the pixel defining structure further comprises: a lyophilic material layer between a setting surface of the pixel defining layer and the lyophobic material layer, the lyophilic material layer attracting liquid

Methodology Applied

Scientific EffectHydrophilic effect: Hydrophile

Data Source

PatentUS11495779B2Pixel defining layer and manufacturing method thereof, array substrate and display device

Publication Date: 2022.11.08 BEIJING BOE TECH DEV CO LTD

AI summary

The present disclosure discloses a pixel defining layer and a manufacturing method thereof, an array substrate and a display device, and belongs to the field of display technology. The pixel defining layer includes a plurality of pixel defining structures arranged in an array, wherein the pixel defining structure includes a first bottom surface and a second bottom surface opposite each other, and a side surface located between the first bottom surface and the second bottom surface. Since the side surface is non-planar, the structure between the side surface and the bottom surface close to the base substrate constitutes a capillary structure. During the inkjet printing process, the solution in which the organic light emitting material is dissolved can spread more evenly under the attraction of the capillary structure.