Color Conversion Pad Deposition Using Structured Surface Potential

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Solution Overview

Problem

Existing methods for manufacturing optoelectronic devices with color conversion pads face challenges, particularly with small pixel pitches, due to alignment and overlapping issues of light conversion pads, and require precise positioning of electret layers which can be impractical.

Innovation Solution

A method involving the creation of an electret layer with structured surface potential zones, where each conversion zone is formed of polarized and non-polarized elementary zones, allowing for localized deposition of photoluminescent particles to form color conversion pads, improving alignment and deposition uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional deposition methods are used to form color conversion pads, then the manufacturing process is simple, but alignment precision and positioning accuracy deteriorate for small pixel pitches

Engineering Contradiction:
Improvealignment precision of color conversion padsVSAvoidcomplexity of electret layer structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The electret layer is segmented into multiple elementary zones with different surface potentials (polarized zones with non-zero potential and non-polarized zones with zero potential). This segmentation creates distinct regions that guide photoluminescent particle deposition precisely to desired locations, solving the alignment precision problem for small pixel pitches while maintaining a manageable overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the electret layer are赋予 different surface potential characteristics - polarized zones have non-zero surface potential to attract photoluminescent particles, while non-polarized zones have zero surface potential to prevent deposition. This local differentiation enables precise spatial control of color conversion pad formation, achieving high positioning accuracy without excessive overall complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If electret layer positioning is made precise, then color conversion pad positioning improves, but the manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improvepositioning accuracy of color conversion padsVSAvoidease of electret layer fabrication
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The electret layer is pre-structured with polarized and non-polarized elementary zones before the photoluminescent particle deposition step. This preliminary structuring of surface potentials ensures that when particles are deposited, they automatically self-align to the correct positions without requiring complex real-time positioning mechanisms, thereby improving positioning accuracy while simplifying the overall manufacturing process.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If photoluminescent particles are deposited uniformly, then color conversion efficiency improves, but particles may deposit in wrong areas causing overlapping

Engineering Contradiction:
Improvehomogeneity of particle depositionVSAvoidoverlapping of color conversion pads
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The electret layer is designed with polarized zones that have uniform non-zero surface potential, creating equipotential regions that uniformly attract photoluminescent particles. This ensures homogeneous particle distribution within the desired conversion areas. Meanwhile, non-polarized zones with zero potential act as barriers that prevent particle deposition, thereby preventing overlapping between adjacent color conversion pads.

Inventive Principle:
Principle #12Equipotentiality

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 approach enhances the homogeneity of photoluminescent particle deposition, improves the positioning of color conversion pads, and increases the contrast of luminous pixels, particularly in devices with small pixel pitches.

Implementation Method 1

bringing the electret layer into contact with a colloidal solution containing photoluminescent particles, which are deposited on the electret layer in the conversion zones

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 2

the nanocrystals present then being deposited on the electric charge patterns by dielectrophoresis

Methodology Applied
Scientific EffectDielectrophoresis: Dielectric Permittivity

Implementation Method 3

The light conversion pads may be formed from a binder matrix comprising particles of a photoluminescent material such as yttrium aluminum garnet (YAG, for Yttrium Aluminium Garnet, in English) activated by the cerium ion YAG:Ce

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4572574A1Method for manufacturing an optoelectronic device with color conversion by localized deposition of photoluminescent particles on predefined conversion areas with structured surface potential
Publication Date: 2025.06.18 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4572574A1 patent drawingFigure 1A~1C
  • EP4572574A1 patent drawingFigure 2~3B
  • EP4572574A1 patent drawingFigure 4A~4C

AI summary

The invention relates to a method for manufacturing an optoelectronic device with a matrix (20) of diodes (D), comprising the following steps: - producing an electret layer (30) having conversion zones (Zc) separated two by two by a spacing zone (Ze) with zero surface potential, where each conversion zone (Zc) is formed of a plurality of elementary zones called polarized (32) with non-zero surface potential spaced two by two by an elementary zone called non-polarized (33) with zero surface potential, so that the conversion zone (Zc) has a structured surface potential; - producing color conversion pads (P), by bringing the electret layer (30) into contact with a colloidal solution (S) containing photoluminescent particles (p). The invention also relates to the optoelectronic device resulting from said method.