Mini/Micro LED Passivation Structure for High-Contrast Backlights

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Solution Overview

Problem

Existing display technologies using mini and micro scale light-emitting diodes (LEDs) face challenges in achieving picture contrast comparable to organic light-emitting diode (OLED) displays while retaining the advantages of liquid crystal displays (LCDs).

Innovation Solution

The design of a light-emitting device with specific electrode and passivation layer configurations, including via holes and passivation portions, along with reflective layers and planarization layers, enhances the connection and coverage of electrodes, improving the structural integrity and light emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If mini and micro scale light-emitting diodes are used, then the picture contrast reaches OLED level, but the manufacturing complexity and electrode connection difficulty increase

Engineering Contradiction:

Improvepicture contrastVSAvoidelectrode connection structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent extends the passivation layer in the vertical dimension to cover the sidewall of the light-emitting stacked layer, creating a three-dimensional protective structure. This vertical extension allows the passivation layer to provide comprehensive coverage without adding horizontal complexity to the electrode connection structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The passivation layer acts as an intermediary element between the light-emitting stacked layer and the external environment. By positioning the via hole within this intermediary layer, the patent facilitates controlled electrical connection while maintaining isolation and protection of the delicate mini/micro LED structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the passivation layer covers the sidewall of the light-emitting stacked layer, then the structural integrity and protection are improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvestructural integrityVSAvoidpassivation layer alignment

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The passivation layer is formed to cover the sidewall of the light-emitting stacked layer before the via hole is created. This preliminary coverage establishes a robust protective structure in advance, and the via hole is subsequently formed through this pre-established passivation layer, simplifying the overall manufacturing sequence.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The passivation layer is divided into functional portions: a first passivation portion covering the top surface and a second passivation portion covering the sidewall. This segmentation allows each portion to be optimized independently for its specific protective function while maintaining overall manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

3Reliability

If via holes are formed in the passivation layer for electrode connection, then the electrical connectivity is improved, but the risk of damage to the light-emitting stacked layer increases

Engineering Contradiction:

Improveelectrical connectivityVSAvoiddamage risk during via formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The passivation layer is formed as a cushioning protective layer before the via hole formation process. This pre-formed layer absorbs and distributes the mechanical stress and potential damage during via hole creation, protecting the underlying light-emitting stacked layer from direct exposure to harmful manufacturing processes.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS20260026142A1Light-Emitting Device, Light-Emitting Substrate, Backlight Module, and Display Apparatus

Publication Date: 2026.01.22 BEIJING BOE TECH DEV CO LTD

AI summary

A light-emitting device includes a first electrode, a light-emitting stacked layer, a second electrode and a passivation layer. The light-emitting stacked layer is connected to the first electrode. The passivation layer includes a first passivation portion and a second passivation portion. The first passivation portion covers a surface of the light-emitting stacked layer away from the first electrode. The first passivation portion is provided therein with a first via hole. The second electrode is connected to the light-emitting stacked layer through the first via hole. The second passivation portion covers a sidewall of the light-emitting stacked layer and extends to a side of the light-emitting stacked layer away from the second electrode. A distance between a portion of the second passivation portion exceeding the light-emitting stacked layer and the light-emitting stacked layer is greater than a thickness of the first electrode.