Micro LED Wafer Auxiliary Pattern for Precise Pixel Alignment

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Solution Overview

Problem

Micro LEDs with small sizes present challenges in handling and mounting on display panels, leading to defects and high cost losses due to mounting failures, with difficulty in repairing defective micro LEDs and aligning them accurately.

Innovation Solution

A wafer is designed with a transparent substrate and a light blocking layer that includes unit pixel regions and observation regions, featuring an auxiliary pattern to facilitate precise alignment and measurement of micro LEDs, allowing for easy handling and selection of favorable unit pixels for mounting on a display panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If micro LEDs are arranged densely on a two-dimensional plane to realize various images, then the display capability is improved, but the handling difficulty and mounting complexity increase significantly

Engineering Contradiction:

Improvedisplay capabilityVSAvoidhandling ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent divides the wafer into multiple unit pixel regions, each containing sub-pixel regions for different colors (red, green, blue). This segmentation allows individual unit pixels to be handled and mounted separately, reducing the complexity of handling densely arranged micro LEDs while maintaining the display capability of the complete wafer.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If micro LEDs are mounted directly on the display panel, then the mounting process is simplified, but the repairability of defective micro LEDs becomes extremely difficult

Engineering Contradiction:

Improvemounting process simplicityVSAvoiddefective micro LED repairability

Core Design Contradiction:

Ease of manufactureVSEase of repair

Solution Approach 1:

The patent structures the wafer with distinct unit pixel regions that can be individually separated and mounted on the display panel. This allows defective unit pixels to be identified and replaced independently without requiring access to or manipulation of individual micro LEDs already mounted on the panel, thus maintaining mounting simplicity while enabling repairability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces unit pixels as intermediary components between the micro LEDs and the display panel. These unit pixels serve as manageable units that simplify the mounting process while also enabling easier repair, as defective unit pixels can be replaced without directly manipulating the tiny micro LEDs on the panel.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If transferring process is used to mount micro LEDs in a group on the wafer, then the processing time is reduced, but the alignment precision becomes difficult to control

Engineering Contradiction:

Improveprocessing speedVSAvoidalignment precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent pre-arranges micro LEDs in specific unit pixel regions on the wafer before the transferring process. This preliminary arrangement establishes reference positions that facilitate accurate alignment during the group transferring process, maintaining both high productivity and alignment precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical alignment methods with optical observation methods. By providing observation regions with auxiliary patterns visible through the transparent substrate, the system uses optical detection to ensure alignment precision during the group transferring process, maintaining both speed and accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If adhesive layer is used to attach light emitting devices on the wafer, then the mounting process is simplified, but the measurement of deviation from correct locations becomes difficult when the adhesive layer is deformed

Engineering Contradiction:

Improvemounting process simplicityVSAvoiddeviation measurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces auxiliary patterns as intermediary reference markers between the adhesive layer and the measurement system. These patterns are disposed around the mounting regions in observation areas, providing stable reference points that remain visible even when the adhesive layer deforms, thus enabling continued measurement of deviation from correct locations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement of micro LED positions through the deformed adhesive layer with optical observation of auxiliary patterns. The auxiliary patterns provide reference markers that can be optically detected to determine alignment accuracy, maintaining measurement precision despite adhesive layer deformation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12439758B2Wafer having auxiliary pattern for aligning light emitting device and method of fabricating unit pixel using the same

Publication Date: 2025.10.07 SEOUL VIOSYS CO LTD

AI summary

A wafer for fabricating a unit pixel is provided. The wafer includes a transparent substrate, and a light blocking layer disposed on the transparent substrate. The light blocking layer includes a plurality of unit pixel regions and at least one observation region. Each of the unit pixel regions has a mounting region for mounting a light emitting device, and the observation region includes the mounting region for mounting the light emitting device and an auxiliary pattern disposed around the mounting region.