Patterned Light-Transmitting Display Panel for Bendable Light Extraction

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Solution Overview

Problem

Display panels suffer from poor bendability and increased thickness due to the use of a whole light-transmitting layer formed by ink-jet printing, which reduces light-exit efficiency.

Innovation Solution

A display panel design featuring a patterned light-transmitting pattern with multiple structures that form a lens-like structure, enhancing light-exit efficiency while maintaining bendability by using a patterning process instead of ink-jet printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple electrode structure without separate EPL and EHL electrodes is used, then device complexity is reduced, but display uniformity and quality deteriorate due to inability to independently control electric fields for pixel definition and hole injection

Engineering Contradiction:
Improveelectrode structureVSAvoiddisplay uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The electrode structure is segmented into functionally distinct components: a common electrode, pixel electrodes (with EPL and EHL sub-layers), and hole injection layers. This segmentation allows independent optimization of electric field distribution for pixel definition and charge injection, resolving the contradiction between structural simplicity and display uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pixel electrode structure integrates multiple functions into a unified component: the EPL layer provides pixel definition through its conductive properties, while the EHL layer simultaneously facilitates hole injection. This multi-functional design achieves improved display uniformity without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If conventional ITO electrodes are used without additional layers, then manufacturing steps are reduced, but display quality deteriorates due to insufficient hole injection efficiency and lack of pixel definition

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidhole injection efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The EHL (electron hole injection) layer is introduced as a preliminary functional layer between the ITO electrode and the liquid crystal layer. This preliminary action of adding a specialized injection layer ensures efficient hole injection before the liquid crystal material is applied, resolving the contradiction between manufacturing efficiency and injection reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The electrode structure uses composite material design combining ITO (indium tin oxide) with organic EPL and EHL layers. This composite structure leverages the excellent conductivity of ITO while adding the specialized charge injection and pixel definition capabilities of the organic layers, achieving improved reliability without completely replacing the conventional ITO electrode.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If EPL and EHL layers are formed separately with multiple patterning steps, then pixel definition accuracy is improved, but manufacturing complexity and time increase

Engineering Contradiction:
Improvepixel definition accuracyVSAvoidpatterning process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The EPL and EHL layers are merged into a single patterning step using a unified photoresist layer. The photoresist pattern simultaneously defines both the EPL and EHL regions, allowing pixel definition accuracy to be achieved without the complexity of separate patterning steps for each layer.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The photoresist layer serves multiple functions: it acts as the patterning mask for both EPL and EHL formation, and also serves as the etch stop layer. This multi-functional use of a single material layer achieves precise pixel definition while simplifying the manufacturing process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Ease of manufacture

If photoresist is used only as a patterning mask and then removed, then patterning simplicity is maintained, but material waste increases and environmental burden increases

Engineering Contradiction:
Improvepatterning process simplicityVSAvoidphotoresist waste
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

Instead of discarding the photoresist after patterning, the process recovers and repurposes it as the EHL (electron hole injection) layer. The photoresist is retained, treated to enhance its charge injection properties, and integrated into the final device structure, eliminating waste while maintaining patterning simplicity.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The photoresist, which would normally be considered waste material requiring disposal, is converted into a beneficial functional layer (EHL) that improves device performance. This transformation turns the harmful aspect of material waste into a benefit by creating a necessary component for efficient hole injection.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4447021B1Display panel, manufacturing method for display panel, and display apparatus
Publication Date: 2026.05.06 BOE TECHNOLOGY GROUP CO LTD
  • EP4447021B1 patent drawingFigure 1~2
  • EP4447021B1 patent drawingFigure 3
  • EP4447021B1 patent drawingFigure 4~5

AI summary

Provided are a display panel, a manufacturing method for the display panel, and a display apparatus. The display panel (20) comprises a base substrate (21), and a light-emitting unit (22), a light-transmitting layer (23) and a light-transmitting pattern (24), which are provided on the base substrate (21), wherein an opening (K1) in the light-transmitting layer (23) is opposite the light-emitting unit (22); and the light-transmitting pattern (24) comprises light-transmitting structures (241), the light-transmitting structures (241) covering the opening (K1) in the light-transmitting layer (23) and covering part of the light-transmitting layer (23), so that the light-transmitting structures (241) and the opening (K1) in the light-transmitting layer (23) can form a structure similar to the structure of a lens, thereby improving the light emission efficiency of the display panel (20). Since the light-transmitting pattern (24) comprises a plurality of light-transmitting structures (241) and is not of a whole-layer structure, the bending performance of the display panel (20) cannot be reduced, thereby solving the problem in the related art of poor bending performance of the display panel (20), and thus achieving the effect of improving the bending performance of the display panel (20).