Micro LED Display Common Electrode Segmentation
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Solution Overview
Problem
The existing micro LED display panels using indium tin oxide (ITO) for common electrodes face challenges with high-temperature processing limitations, leading to reduced light transmittance and electrical conductivity, which affects the light-emitting efficiency and manufacturing yield due to the material's low flexibility and toughness.
Innovation Solution
A light-emitting diode display design featuring a first common electrode that exposes part of the upper surface of the micro light-emitting devices' second type electrodes and a second common electrode located between them, without direct contact, utilizing metallic or conductive polymer materials to enhance electrical conductivity and light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO is used to form the common electrode with sufficient thickness for good electrical conductivity, then electrical conductivity is improved, but light transmittance decreases and light-emitting efficiency is lowered
Solution Approach 1:
The common electrode is divided into two separate electrodes: a first common electrode made of transparent conductive material (ITO) that provides light transmittance, and a second common electrode made of metallic material that provides electrical conductivity. This segmentation allows each electrode to optimize its material properties for its specific function without compromising the other.
Solution Approach 2:
Different regions of the electrode structure are assigned different materials with optimized properties: the first common electrode uses ITO for high light transmittance in the light emission path, while the second common electrode uses metallic material for high electrical conductivity in the electrical connection path. This local quality differentiation resolves the contradiction between transmittance and conductivity requirements.
2Illumination intensity
If ITO is used for the common electrode, then light transmittance is improved, but electrical conductivity decreases and manufacturing flexibility is reduced
Solution Approach 1:
The electrode system is segmented into two functional components: the first common electrode (ITO) handles light transmittance, while the second common electrode (metallic material) handles electrical conductivity. This segmentation allows each material to perform its optimal function.
Solution Approach 2:
The common electrode system uses a composite structure combining two different materials (ITO and metallic material) with complementary properties. This composite approach leverages the high transmittance of ITO and the high conductivity of metals, achieving both requirements simultaneously.
3Reliability
If a thick common electrode is used to ensure good electrical conductivity, then electrical conductivity is improved, but light transmittance decreases
Solution Approach 1:
The thick electrode function is segmented between two layers: a thin transparent ITO layer for light transmittance and a separate metallic layer for conductivity. This eliminates the need for a single thick electrode that would block light.
Solution Approach 2:
The solution moves from a single-dimensional thickness parameter to a two-dimensional layered structure. Instead of increasing thickness in one direction to improve conductivity, the patent uses vertical layering with different material properties, allowing conductivity improvement without compromising transmittance.
4Illumination intensity
If ITO is used for the common electrode, then light transmittance is improved, but manufacturing flexibility and toughness decrease
Solution Approach 1:
The electrode system combines brittle transparent ITO with more flexible metallic material. The metallic second common electrode provides manufacturing flexibility and toughness that complements the optical properties of ITO, making the overall structure easier to manufacture while maintaining high transmittance.
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 configuration improves the forward light-emitting efficiency and electrical conductivity of micro LEDs, increasing the display's transverse conductivity and manufacturing yield while reducing manufacturing difficulties.
Implementation Method 1
a common electrode and a micro light-emitting diode (LED) of a display panel are disposed in a display region, wherein the micro LED is located in each pixel structure region and is electrically connected to the common electrode, and an image is displayed by means of a driving control between the common electrode and the micro LED
Data Source
AI summary
A light emitting diode display includes a driving substrate, a plurality of micro light-emitting devices, a first common electrode, and a second common electrode. The micro light-emitting devices are arranged on the driving substrate. Each of the micro light-emitting devices includes an epitaxial structure, a first type electrode, and a second type electrode. The first common electrode is disposed on the driving substrate and located between the second type electrodes of the micro light-emitting devices, wherein the first common electrode exposes at least a portion of an upper surface of each of the second type electrodes. The second common electrode is located between the second type electrodes of the micro light-emitting devices and electrically connected to the first common electrode, wherein the second common electrode does not directly contact the micro light-emitting devices.