Micro LED Package Layout With Stacked Driver and Subpixel Layers

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Solution Overview

Problem

Current display devices using micro LEDs face challenges with increased size of light-emitting element packages due to the integration of driver ICs, leading to higher process costs and light loss, which affects image quality and area utilization.

Innovation Solution

A light-emitting element package design where the driver chip and light-emitting elements are in separate layers, allowing for active matrix driving and improved image quality, with a terminal layer for connecting the driver chip and light-emitting elements, and a layer for light emission, enabling smaller package sizes and increased area utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the driver IC is disposed on the same layer as the LED, then the light-emitting element package can be manufactured, but the size of the light-emitting element package increases

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidpackage size
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent transitions from a planar arrangement where the driver IC and LED share the same layer to a three-dimensional stacked architecture. The driver chip is positioned in a second layer directly beneath the light-emitting elements in the third layer, utilizing vertical space to reduce the horizontal footprint of the package while maintaining all necessary functional connections.

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

2Ease of manufacture

If the driver IC is disposed on the same layer as the LED, then the light-emitting element package can be manufactured, but the number of transfers increases leading to increased process cost

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidprocess cost
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent integrates the driver chip and light-emitting elements into a single packaged unit where both components are mounted on the same substrate and interconnected through vertical connections. This merged structure allows both components to be transferred and mounted together as one assembly, reducing the number of separate transfer operations required compared to handling them as separate components.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the driver IC is disposed on the same layer as the LED, then the light-emitting element package can be manufactured, but light emitted from the LED is absorbed by the driver IC resulting in light loss

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidlight loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

By moving the driver IC to a separate layer beneath the light-emitting elements, the patent positions the light-emitting components vertically above the driver chip. This spatial separation in the vertical dimension prevents the driver IC from intercepting and absorbing the light emitted by the LEDs, thereby eliminating the light loss issue while maintaining electrical connectivity through vertical connections.

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

4Area of stationary object

If the package size is reduced by separating driver chip and LED into different layers, then area utilization increases, but the structure becomes more complex

Engineering Contradiction:
Improvearea utilizationVSAvoidstructure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the light-emitting element package into distinct functional layers: a first layer containing terminals, a second layer containing the driver chip, and a third layer containing the light-emitting elements. This segmentation separates different functions into dedicated layers, which simplifies the design and manufacturing process despite the multi-layer structure, as each layer can be optimized and processed independently.

Inventive Principle:
Principle #1Segmentation

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 design enhances image quality, reduces manufacturing costs, and allows for more pixels in the same area, increasing display resolution and enabling the production of new structures like large-area transparent displays.

Implementation Method 1

LED (light emitting diode), which is a well-known semiconductor light-emitting element that converts electric current into light

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP4462481A1Light-emitting element package, display device using the same, and method for manufacturing said display device
Publication Date: 2024.11.13 LG ELECTRONICS INC
  • EP4462481A1 patent drawingFigure 1
  • EP4462481A1 patent drawingFigure 2
  • EP4462481A1 patent drawingFigure 3

AI summary

The present disclosure is applicable to the field of display devices, for example to a display device using a micro light-emitting diode. The disclosed light-emitting element package (200) includes: a first layer (210) including a terminal (211; 212), a second layer (220) located adjacent to the first layer and including a driving chip (250), a third layer (230) located adjacent to the second layer, wherein the third layer includes light-emitting elements (260), wherein each light-emitting element at least partially overlaps the driving chip in a connection direction of the first layer and the second layer and constitutes a unit subpixel, and a fourth layer (240) located adjacent to the third layer, wherein light emitted from the light-emitting elements passes through the fourth layer. A first electrode (262) of each of the light-emitting elements is connected to a first end (251) of the driving chip, and a second end (252) of the driving chip is connected to the terminal.