White-Light iLED Structure With Series RGB LEDs and Shared Drive

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Solution Overview

Problem

Existing micro-LED displays face challenges in achieving white light emission efficiently due to the large thickness required for phosphors or quantum dots, leading to increased circuit complexity, wiring, and assembly costs, while separate power supplies for each color pixel reduce display resolution and increase costs.

Innovation Solution

A white-light-emitting inorganic light-emitting-diode (iLED) structure comprising first iLEDs connected in series, with second iLEDs connected in series or parallel to emit the same color, disposed on a common substrate, and a simplified power supply system to reduce circuitry and improve efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If phosphors or quantum dots are used to convert blue light to white light in micro-LEDs, then white light emission is achieved, but the required layer thickness (20-100 microns) is much larger than the micro-LED thickness (less than 20 microns), reducing light emission efficiency

Engineering Contradiction:
Improvewhite light emissionVSAvoidlight emission efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent combines multiple micro-LEDs of different colors (red, green, blue) into a single integrated structure that directly emits white light when all sub-LEDs are activated simultaneously. This eliminates the need for separate phosphor conversion layers, allowing the emission thickness to match the micro-LED thickness and significantly improving light emission efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Use of energy by moving object

If separate power supplies are provided for each color pixel to optimize current density and voltage, then lighting efficiency is improved, but circuit complexity, wiring requirements, and assembly costs increase significantly

Engineering Contradiction:
Improvelighting efficiencyVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements a single power supply system that serves all micro-LEDs in the display through a common anode and cathode configuration. The controller selectively activates different color combinations by controlling current distribution, allowing one power supply to fulfill the lighting function for all pixels, thereby reducing circuit complexity while maintaining efficient operation.

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

3Reliability

If multiple power supplies and control circuits are used for each color pixel, then optimal current density and voltage are achieved for each LED, but the number of wires and connections increases, reducing display resolution

Engineering Contradiction:
Improvecurrent density optimizationVSAvoiddisplay resolution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent merges the power supply and control functions into a single integrated system where one power supply serves all micro-LEDs through a common electrical connection structure. The controller manages current distribution to multiple LED groups, eliminating the need for separate wiring for each pixel and enabling higher display resolution with reduced interconnect density.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If red, green, and blue micro-LEDs are combined in a color pixel to emit white light, then full-color display capability is achieved, but the circuit complexity and assembly costs increase

Engineering Contradiction:
Improvecolor display capabilityVSAvoidcircuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal power and control architecture where a single power supply and controller serve all color pixels in the display. Each pixel contains red, green, and blue micro-LEDs that can be independently controlled to produce various colors or white light, while the common electrical structure reduces overall circuit complexity and simplifies assembly procedures.

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

The solution enhances power efficiency, reduces circuitry and assembly costs, and improves color temperature and resolution by optimizing current density and voltage distribution across iLEDs, allowing for higher resolution displays with improved white light emission.

Implementation Method 1

Inorganic light-emitting diodes (iLEDs) are semiconductor light sources relying on p-n junctions to emit light when a suitable voltage is applied across the light-emitting diode

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

white light is achieved by combining a high-frequency-light-emitting i LED (for example blue) with phosphors or quantum dots that absorb the iLED-emitted high-frequency light and emit a complementary, lower-frequency light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4158421B1White-light-emitting LED structures
Publication Date: 2025.07.02 X DISPLAY CO TECH LTD
  • EP4158421B1 patent drawingFigure 1~3
  • EP4158421B1 patent drawingFigure 4~6
  • EP4158421B1 patent drawingFigure 7

AI summary

A white-light-emitting inorganic light-emitting-diode (iLED) structure comprises first iLEDs electrically connected in series, each first iLED emitting a different color of light from any other first iLED when electrical power is provided to the first iLEDs, and a second iLED electrically connected to one of the first iLEDs, the second iLED emitting the same color of light as the one of the first iLEDs when electrical power is provided to the first iLEDs. The second iLED can be electrically connected in series or in parallel with the one of the first iLEDs. Such iLED structures can be used at least in displays, lamps, and indicators.