Micro LED Transfer Mold with Protrusions for Alignment

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Solution Overview

Problem

The productivity of micro LED display devices is reduced as the sizes of micro LEDs decrease and display sizes increase, due to inefficiencies in the pick and place method used for transferring micro LEDs.

Innovation Solution

A display transferring structure with a mold having recesses and protrusions on its surface, where the protrusions are narrower than the micro LEDs and spaced such that they allow for fluid self-alignment, preventing the LEDs from being fixed on the surface and ensuring they are placed within the recesses, thereby improving alignment and transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pick and place method is used for transferring micro LEDs, then the transfer process can be performed, but the productivity is reduced as the sizes of micro LEDs are reduced and the sizes of the displays are increased

Engineering Contradiction:
Improvetransfer efficiencyVSAvoidnumber of micro LEDs
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The transferring substrate is divided into multiple recesses, each capable of holding a micro LED chip. This segmentation allows parallel processing of multiple chips simultaneously, dramatically increasing transfer efficiency compared to sequential pick-and-place methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Micro LED chips are pre-positioned in the recesses of the transferring substrate before the actual transfer to the display substrate. This preliminary arrangement enables batch transfer operations, improving productivity by transferring multiple chips in one operation rather than individually.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the pick and place method is used for transferring micro LEDs, then the transfer process can be performed, but alignment precision deteriorates with reduced micro LED sizes

Engineering Contradiction:
Improvealignment precisionVSAvoidsize of micro LEDs
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

Protrusions are provided on the outer surface of the mold at specific locations corresponding to the recesses. These localized structural features provide precise positioning references for the micro LED chips, ensuring accurate alignment even as chip sizes decrease. The protrusions create defined engagement points that maintain manufacturing precision.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention introduces vertical dimension elements (protrusions rising from the mold surface) to enhance horizontal alignment precision. By adding height to the positioning features, the system achieves better alignment control without being constrained by the reduced planar dimensions of the micro LEDs.

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

3Manufacturing precision

If protrusions are provided on the mold surface, then alignment precision is improved, but the complexity of the mold structure increases

Engineering Contradiction:
Improvealignment precisionVSAvoidmold structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The protrusions are integrated with the mold as a unified structure rather than being separate components. This merging of the positioning features into the mold body simplifies the overall system while maintaining alignment precision, avoiding the need for additional separate positioning mechanisms.

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 structure enhances the manufacturing yield by ensuring micro LEDs are correctly positioned on a large-area substrate, improving the efficiency of the transfer process and reducing defects, resulting in a higher clean state of the LEDs within the recesses.

Implementation Method 1

the protrusions are narrower than the micro LEDs and spaced such that they allow for fluid self-alignment, preventing the LEDs from being fixed on the surface

Methodology Applied
Scientific EffectFluid self-alignment: Capillary Action

Data Source

PatentEP4040485A1Display transferring structure and display device including the same
Publication Date: 2022.08.10 SAMSUNG ELECTRONICS CO LTD
  • EP4040485A1 patent drawingFigure 1~2
  • EP4040485A1 patent drawingFigure 3~4
  • EP4040485A1 patent drawingFigure 5

AI summary

A display transferring structure includes a transferring substrate including a mold including a plurality of recesses, and a plurality of protrusions provided on an outer surface of the mold connected to the plurality of recesses; and micro semiconductor chips arranged in the recesses. When the micro semiconductor chips are wet aligned, by such protrusions, sliding of the micro semiconductor chips toward the inside of the recesses may be improved.