Micro LED Lens Transfer Structure Without Post-Transfer Lithography

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The manufacturing process of micro light emitting diode displays is complicated and costly due to the need for a photolithography process to form lenses after transferring micro light emitting diodes, which affects the reliability and lifespan of the display apparatus.

Innovation Solution

A manufacturing method that simultaneously transfers micro light emitting diodes and lenses onto an array substrate using a stamp with concave portions, eliminating the need for a separate photolithography process to form lenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a photolithography process is performed to form lenses after transferring micro light emitting diodes, then the lens structure can be formed with precise geometry, but the manufacturing process becomes complicated and manufacturing cost increases

Engineering Contradiction:
Improvelens geometry precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming lenses on the stamp before transferring micro light emitting diodes. The stamp is prepared with lens structures in advance, so that when the transfer occurs, the lenses are already in position. This eliminates the need for subsequent photolithography processes to form lenses, thereby simplifying the manufacturing process while maintaining precise lens geometry through the pre-formed stamp structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the lens formation process with the micro light emitting diode transfer process. Instead of performing these as separate sequential steps (first transfer LEDs, then form lenses), the invention combines them into a single integrated transfer operation where both the lenses and micro light emitting diodes are transferred simultaneously using the same stamp, reducing process complexity and manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If a photolithography process is performed to form lenses after transferring micro light emitting diodes, then the lens structure can be formed with precise geometry, but manufacturing cost increases

Engineering Contradiction:
Improvelens geometry precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming lenses on the stamp before transferring micro light emitting diodes. The stamp is prepared with lens structures in advance, so that when the transfer occurs, the lenses are already in position. This eliminates the need for subsequent photolithography processes to form lenses, thereby simplifying the manufacturing process while maintaining precise lens geometry through the pre-formed stamp structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the lens formation process with the micro light emitting diode transfer process. Instead of performing these as separate sequential steps (first transfer LEDs, then form lenses), the invention combines them into a single integrated transfer operation where both the lenses and micro light emitting diodes are transferred simultaneously using the same stamp, reducing process complexity and manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

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 method simplifies the manufacturing process and reduces costs while improving light extraction efficiency and reducing power consumption of the display apparatus.

Implementation Method 1

a lens disposed on the micro light emitting diode

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4576213A1Display apparatus
Publication Date: 2025.06.25 LG DISPLAY CO LTD
  • EP4576213A1 patent drawingFigure 1
  • EP4576213A1 patent drawingFigure 2
  • EP4576213A1 patent drawingFigure 3

AI summary

There is disclosed a display apparatus including a substrate (110), a first electrode (131) and a second electrode (132) that are disposed on the substrate (110), a bank layer (135) disposed on the first electrode and the second electrode, the bank layer comprising an opening (OP), a micro light emitting diode (ED1) disposed inside the opening of the bank layer (135), a high refractive index layer (LS or lens) disposed on the micro light emitting diode, an overcoat layer (151) disposed on the high refractive index layer (LS) and having a lower refractive index than the high refractive index layer, and a fixation member (143) disposed between the high refractive index layer and the bank layer (135).