Stacked RGB LED Display Module for Fine-Pitch Color Control

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Solution Overview

Problem

Current display technologies, such as LCDs and AMOLEDs, face challenges in achieving fast response times and flexibility, while semiconductor light emitting elements struggle with implementing RGB color at high fine pitches due to small sub-cell pitch requirements and color crosstalk issues.

Innovation Solution

A display device configuration where red, green, and blue semiconductor light emitting elements are laminated, with distributed Bragg reflectors and light transmittance adhesive layers used to manage color emission and reduce inter-cell pitch limitations, allowing for fine pitch displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If red, green, and blue semiconductor light emitting elements are disposed side by side for RGB color display, then color display capability is improved, but the pitch between sub-cells becomes extremely small making implementation technically difficult

Engineering Contradiction:
ImproveRGB color display capabilityVSAvoidpitch between sub-cells
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent transitions from a planar side-by-side arrangement of RGB semiconductor light emitting elements to a vertical stacked configuration. By stacking the elements in the thickness direction (z-axis) rather than arranging them horizontally (x-y plane), the patent achieves RGB color display while maintaining larger horizontal pitch between sub-cells, thus resolving the technical difficulty of implementing extremely small pitch displays.

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

Solution Approach 2:

The patent employs a stacked configuration where red, green, and blue semiconductor light emitting elements are vertically nested one above another. This nesting approach allows multiple color elements to occupy a smaller horizontal footprint while maintaining their individual functionality, effectively solving the pitch limitation problem in fine pitch displays.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Speed

If semiconductor light emitting elements are used for display, then fast response time and flexibility are improved, but implementing fine pitch displays with RGB color becomes technically difficult

Engineering Contradiction:
Improveresponse timeVSAvoidimplementation complexity of fine pitch RGB display
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

By stacking semiconductor light emitting elements vertically, the patent reduces the horizontal complexity of routing and positioning extremely fine pitch elements while preserving the inherent fast response time and flexibility advantages of semiconductor LEDs. The vertical arrangement simplifies the overall device structure for fine pitch applications.

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

3Measurement precision

If distributed Bragg reflectors are added between semiconductor light emitting elements to manage color emission, then color accuracy is improved, but device structure becomes more complex

Engineering Contradiction:
Improvecolor accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The distributed Bragg reflectors in the stacked configuration serve multiple functions: they reflect specific wavelengths to improve color accuracy, they act as part of the optical cavity structure, and they help manage light extraction efficiency. By integrating these reflectors into the existing stacked architecture, the patent achieves color accuracy improvement while minimizing additional structural complexity.

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

Enables the production of high-resolution, flexible display devices with improved color accuracy and reduced inter-cell spacing, overcoming the limitations of traditional technologies.

Implementation Method 1

between the red semiconductor light emitting element and the green semiconductor light emitting element, a first distributed Bragg reflector (DBR) that penetrates red and reflects green may be disposed

Methodology Applied
Scientific EffectDistributed Bragg reflector: Bragg Diffraction

Data Source

PatentEP3648164B1Display device using semiconductor light emitting element
Publication Date: 2023.08.30 LG ELECTRONICS INC
  • EP3648164B1 patent drawingFigure 1
  • EP3648164B1 patent drawingFigure 2
  • EP3648164B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a display device and, more particularly, to a display device using a semiconductor light emitting element. The display device according to the present invention comprises a light emitting element module, wherein the light emitting element module comprises: a red semiconductor light emitting element that emits red light; a green semiconductor light emitting element that is disposed on the top surface of the red semiconductor light emitting element; a blue semiconductor light emitting element that is disposed on the top surface of the green semiconductor light emitting element; an individual electrode portion for supplying an individual signal to each of the red semiconductor light emitting element, the green semiconductor light emitting element, and the blue semiconductor light emitting element; and a common electrode portion for supplying a common signal to the red semiconductor light emitting element, the green semiconductor light emitting element, and the blue semiconductor light emitting element.