Integrated Quantum Dot Display Substrate for Low Leakage

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Solution Overview

Problem

The conventional cell-assembly method for quantum dot display structures in flexible OLEDs leads to issues such as large cell thickness, light leakage, and reduced light emissivity due to the absorption of blue light by the bonding substrates.

Innovation Solution

An integrated display substrate design where the quantum dot layer and electroluminescent device layer are arranged on the same TFT substrate, with a pixel define layer that expands to accommodate these layers, eliminating the need for cell assembly and gluing, and includes a connection layer to ensure electrical connectivity between adjacent pixel pits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cell assembly method is used with two substrates bonded by colloid, then quantum dot display structure can be formed, but cell thickness becomes large causing light leakage

Engineering Contradiction:

Improvedisplay qualityVSAvoidcell thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges the quantum dot color filter layer and the electroluminescence layer onto a single TFT substrate, eliminating the need for cell assembly with two separate substrates. This integration directly reduces cell thickness and prevents light leakage while maintaining display quality.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If colloid bonding is used to assemble two substrates, then cell structure is formed, but blue light absorption increases reducing light emissivity

Engineering Contradiction:

Improvecell structureVSAvoidblue light absorption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the colloid bonding layer from the structure by integrating all functional layers onto one substrate. This extraction eliminates the blue light absorption issue caused by colloid while maintaining the necessary cell structure through alternative layer integration.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If pixel define layer size is increased to accommodate expanded structure, then layers can be stacked, but manufacturing precision requirements increase

Engineering Contradiction:

Improvelayer stackingVSAvoidpixel define layer size control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent utilizes laser irradiation to induce thermal expansion of the pixel define layer, dynamically changing its size parameter to accommodate the stacked layers. This parameter change approach simplifies manufacturing by allowing the structure to self-adjust rather than requiring precise pre-control of layer dimensions.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If quantum dot layer thickness is increased for better light conversion, then display effect improves, but manufacturing complexity increases

Engineering Contradiction:

Improvelight conversion efficiencyVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs laser irradiation to induce thermal expansion of the pixel define layer, which self-adjusts to accommodate the quantum dot layer thickness requirements. This self-service mechanism simplifies manufacturing by eliminating the need for complex precision control systems while maintaining optimal light conversion efficiency.

Inventive Principle:

Principle #25Self-service

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 design reduces substrate thickness, minimizes blue light loss, and prevents surface light leakage and uneven brightness, enhancing the display effect by maintaining optimal light conversion and electrical connectivity.

Implementation Method 1

the pixel define layer is made of directional thermal expansion material... the pixel define layer expands to 10 um to 14 um in a direction facing away from the TFT substrate after laser irradiation

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Quantum Dots (QDs) are also used in flexible display products for their luminous characteristics

Methodology Applied

Scientific EffectQuantum dot luminescence: Photoluminescence

Data Source

PatentUS12364136B2Display substrate, display device, and manufacturing method

Publication Date: 2025.07.15 BOE TECHNOLOGY GROUP CO LTD

AI summary

A display substrate, a display device, and a manufacturing method. The display substrate includes a TFT substrate, and a pixel defining layer provided on the TFT substrate and surrounding a plurality of pixel pits, wherein an electroluminescent device layer, a connection layer, a first encapsulation layer, and a quantum dot layer are sequentially stacked in each pixel pit; the connection layers in the adjacent pixel pits are connected to the side of the pixel defining layer facing away from the TFT substrate; and the connection layers are configured to be electrically connected to the electroluminescent device layers in the two adjacent pixel pits.