Electret Surface Potential Patterning for Aligned Photoluminescent Pads

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Solution Overview

Problem

Existing manufacturing processes for optoelectronic devices with color conversion structures face challenges in aligning and covering photoluminescent studs over diode matrices, particularly for small pixel sizes, leading to positioning uncertainties and performance degradation.

Innovation Solution

A process that creates surface potential patterns on an electret layer optically, either by depolarization or polarization, allowing for simultaneous formation of photoluminescent studs without the need for AFM points or stamps, ensuring precise positioning of photoluminescent studs relative to the diode matrix.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sequential injection of electrical charges using AFM tip is used to create electret layer patterns, then electrical charge patterns can be formed, but the manufacturing process becomes time-consuming and low productivity

Engineering Contradiction:
Improvealignment precision of photoluminescent padsVSAvoidmanufacturing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical sequential injection method (AFM tip moving across the surface) with an optical field-based method. A polarized light source illuminates the electret layer through a mask, creating charge patterns optically rather than mechanically, thereby dramatically increasing manufacturing speed while maintaining precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a full-field polarized electret layer first, then uses optical masking to define the charge patterns in a single step. This preliminary creation of the polarized layer followed by selective masking is more efficient than sequentially injecting charges at each pattern location

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If stamping technique with electrically polarized pad is used to define charge patterns, then electrical charge patterns can be created, but precise positioning relative to diode array becomes difficult leading to alignment errors

Engineering Contradiction:
Improvesimplicity of charge pattern creationVSAvoidpositioning accuracy of photoluminescent pads
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a mask that copies the desired charge pattern geometry onto the electret layer through optical projection. This optical copying method ensures precise reproduction of the pattern at the correct position relative to the diode array, avoiding positioning errors associated with physical stamping

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical stamping process with an optical field-based pattern transfer method. The mask defines the charge patterns through light absorption, eliminating mechanical positioning errors and improving alignment precision between photoluminescent pads and diodes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple sequential deposition steps are performed to create different photoluminescent pads, then color conversion can be achieved, but the process becomes complex and time-consuming

Engineering Contradiction:
Improvecolor conversion capabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple charge pattern definitions into a single optical masking step. By using a mask that contains all necessary charge pattern geometries simultaneously, the method creates patterns for multiple photoluminescent pads in one operation, reducing process complexity while maintaining color conversion versatility

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal polarized electret layer that can serve multiple functions. This single polarized layer can be used to define patterns for different colors (red, green, blue photoluminescent pads) through appropriate mask design, eliminating the need for separate processing steps for each color

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

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 process enables precise and efficient creation of photoluminescent studs, improving the performance and alignment of optoelectronic devices, even for small pixel sizes, by defining surface potential patterns on the electret layer, which enhances the color conversion capability.

Implementation Method 1

illuminate areas of the electret layer with light radiation called depolarization radiation capable of being absorbed at least in part by the electret layer

Methodology Applied
Scientific EffectAbsorption of light radiation: Absorption (EM radiation)

Implementation Method 2

illuminate areas of the electret layer with light radiation of a polarization capable of being absorbed at least in part by the electret layer

Methodology Applied
Scientific EffectAbsorption of light radiation: Absorption (EM radiation)

Implementation Method 3

the nanocrystals present are deposited onto the electrical charge patterns by a dielectrophoretic force

Methodology Applied
Scientific EffectDielectrophoresis:

Data Source

PatentEP4506995A1Method for manufacturing a color-converting optoelectronic device, comprising a step of optically forming surface potential patterns in an electret layer
Publication Date: 2025.02.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4506995A1 patent drawingFigure 1A~1C
  • EP4506995A1 patent drawingFigure 1D~1F
  • EP4506995A1 patent drawingFigure 1G~1H

AI summary

The invention relates to a method for manufacturing an optoelectronic device comprising a diode matrix (10) and photoluminescent pads arranged opposite at least one diode, comprising the following steps: ∘ producing an electret layer (E1) on the diode matrix (10), by localized polarization or depolarization, optically, so as to form surface potential patterns (M1); ∘ producing the photoluminescent pads (P1), by contacting the electret layer (E1) with a colloidal solution containing photoluminescent particles (p1), which are then deposited on the upper face (F1) of the electret layer (E1) opposite the predefined surface potential patterns (M1), thus forming the photoluminescent pads (P1).