Mini LED Backplane Conductive Layout for Encapsulation Stability

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Solution Overview

Problem

Mini LEDs in display technologies experience encapsulation peeling issues due to temperature changes, leading to device failure and reduced service life.

Innovation Solution

A backplane design with specific conductive line configurations and encapsulation portion arrangements that minimize stress concentration regions, enhancing film adhesion and reducing peeling risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If Mini LED devices are used in display technologies, then high brightness and energy efficiency are achieved, but encapsulation peeling occurs due to thermal expansion and contraction

Engineering Contradiction:
ImprovebrightnessVSAvoidencapsulation stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The conductive line is divided into multiple segments (first conductive line segment, second conductive line segment, third conductive line segment) arranged in sequence. This segmentation allows each segment to independently accommodate thermal stress, preventing stress concentration that would cause encapsulation peeling while maintaining electrical connectivity for high brightness LED operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the conductive line structure are designed with different properties: the first segment connects to the anode pad with specific width constraints, the middle segment spans the LED body with optimized dimensions, and the third segment connects to the cathode pad. This local differentiation optimizes both electrical performance and thermal stress distribution, resolving the contradiction between brightness and reliability

Inventive Principle:
Principle #3Local quality

2Reliability

If the conductive line width is reduced to minimize stress concentration, then encapsulation peeling is prevented, but electrical conductivity decreases

Engineering Contradiction:
Improvefilm adhesionVSAvoidelectrical conductivity
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The conductive line structure transitions from a simple linear path to a multi-dimensional configuration with segments arranged in sequence, including vertical and horizontal portions. This dimensional complexity allows the conductive path to maintain adequate width for electrical conductivity while distributing stress across multiple segments, preventing encapsulation peeling

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the distance between conductive line and encapsulation edge is increased to reduce stress concentration, then peeling is prevented, but the usable area for conductive lines decreases

Engineering Contradiction:
Improveencapsulation stabilityVSAvoidconductive line area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The conductive line segments include both vertical portions and horizontal portions with optimized curvature and positioning. The horizontal portions are positioned at specific distances from the LED body edges, creating a curved or angled transition that reduces stress concentration while maximizing the use of available area, thus preventing peeling without sacrificing conductive line area

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4207291B1Backplane and method for manufacturing same, and backlight module and display apparatus
Publication Date: 2025.10.15 BOE TECHNOLOGY GROUP CO LTD
  • EP4207291B1 patent drawingFigure 1~2A-A'
  • EP4207291B1 patent drawingFigure 3~4
  • EP4207291B1 patent drawingFigure 5~6A-A'

AI summary

A backplane, comprising a substrate, a circuit structure layer, a reflection layer, a plurality of electronic devices and a plurality of encapsulation portions, wherein each encapsulation portion covers one electronic device. At least one first electrically conductive wire comprises a first straight-line extension portion, a second straight-line extension portion and a third straight-line extension portion. The orthographic projection of the first straight-line extension portion on the substrate is a first orthographic projection, the orthographic projection of the second straight-line extension portion on the substrate is a second orthographic projection, the orthographic projection of the third straight-line extension portion on the substrate is a third orthographic projection, and the orthographic projection of the encapsulation portions on the substrate is a fourth orthographic projection, wherein the first orthographic projection is located within the fourth orthographic projection; the second orthographic projection partially overlaps the fourth orthographic projection; the third orthographic projection is located outside the fourth orthographic projection; in the fourth orthographic projection, the two end points that are the farthest from each other in the widthwise direction of the second straight-line extension portion are both referred to as first end points; and the distance between the second orthographic projection and a first reference line, which passes through the first end points and is parallel to the second straight-line extension portion, is not less than half of the line width of the second straight-line extension portion.