Micro LED Pixel Circuit With Shared Gate-Capacitor Electrode
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Solution Overview
Problem
Current micro light emitting display technologies face challenges in miniaturizing the size of micro light emitting elements while maintaining high resolution and efficiency, leading to increased production costs and reduced pixel per inch (PPI) due to complex circuit layouts and large line and space requirements.
Innovation Solution
The proposed micro light emitting display apparatus incorporates a micro light emitting element with a driving transistor, a switching transistor, a capacitor, and a metal line configuration that reduces the size of the micro light emitting element to 100 μm or less, with a gate electrode of the driving transistor extending into a first opening to contact the source or drain region of the switching transistor, and a metal line connecting the drain region of the driving transistor to the anode electrode, thereby minimizing circuit layout area and increasing PPI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of micro light emitting elements is reduced to increase PPI, then resolution is improved, but circuit layout area becomes insufficient and manufacturing complexity increases
Solution Approach 1:
The gate electrode of the driving transistor is merged with the first electrode of the capacitor, forming a shared conductive structure. This integration eliminates the need for separate gate electrode and capacitor electrode patterns, reducing the number of lithography steps and pattern alignment requirements, thereby enabling miniaturization while maintaining manufacturability
Solution Approach 2:
The gate electrode of the driving transistor serves dual functions: as the gate electrode for transistor operation and as the first electrode of the capacitor. This multi-functionality reduces the total component count and circuit layout area, allowing for smaller pixel sizes and higher PPI
2Area of stationary object
If the gate electrode extends into the first opening to contact the source or drain region, then the circuit layout area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The first opening is formed in the insulating layer before the gate electrode is deposited, pre-defining the contact region. This preliminary structuring ensures that when the gate electrode is subsequently formed, it automatically aligns with the opening and contacts the source or drain region, reducing the need for high-precision alignment during electrode formation
Solution Approach 2:
The insulating layer with the first opening serves as an intermediary structure that guides and positions the gate electrode. The opening acts as a physical template that ensures proper contact between the gate electrode and the source/drain region, simplifying the manufacturing process while maintaining precision
3Measurement precision
If the micro light emitting element size is reduced to 100 μm or less, then PPI increases, but the capacitor capacitance becomes insufficient
Solution Approach 1:
The capacitor structure utilizes the vertical dimension by forming the second electrode on the opposite side of the insulating layer from the first electrode. This three-dimensional capacitor configuration increases the effective capacitance area without increasing the planar footprint, enabling sufficient capacitance in miniaturized pixels
Solution Approach 2:
The capacitor is nested within the transistor structure by using the gate electrode as the first electrode and forming the second electrode in the insulating layer above or below it. This nested configuration maximizes space utilization, allowing the capacitor to be integrated within the same area as the transistor without requiring additional lateral space
Data Source
AI summary
A micro light emitting display apparatus and a method of manufacturing the micro light emitting display apparatus are disclosed. The micro light emitting display apparatus includes a micro light emitting element, a driving transistor connected to the micro light emitting element, a switching transistor connected to the driving transistor, and a first opening is provided to expose a source region or a drain region of the switching transistor, and a gate electrode of the driving transistor is provided in the first opening and in contact with the source region or the drain region of the switching transistor.