Micro LED Electrode Pad Layout for Higher Light Extraction
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Solution Overview
Problem
Micro LED display devices face a reduction in light emission efficiency due to the blocking of light by electrode pads on the circuit substrate, which hinders the extraction of light emitted from LED chips.
Innovation Solution
The design incorporates first and second electrode pads with light transmission regions on the circuit substrate, allowing light emitted from LED chips to pass through and improve extraction efficiency by using transparent conductive materials and optimizing the structure of these pads to minimize blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrode pads are formed on the circuit substrate to electrically connect LED chips, then electrical connectivity is ensured, but light emission efficiency is reduced due to light blocking by the electrode pads
Solution Approach 1:
The electrode pad is designed with different local properties: a light-transmitting region with high light transmittance (80% or more) and a non-light-transmitting region with low light transmittance (20% or less). This local differentiation allows the pad to simultaneously perform electrical connection and minimize light blocking, resolving the contradiction between reliability and light emission efficiency
Solution Approach 2:
The light-transmitting region uses a transparent conductive material that is substantially transparent to light emitted by the LED chip, while the non-light-transmitting region uses a conductive material that blocks light. This optical property differentiation enables the electrode pad to maintain electrical functionality while reducing light loss
2Illumination intensity
If the circuit substrate is made transparent to allow light extraction, then light emission on the circuit substrate side is improved, but electrical conductivity and signal transmission may be compromised
Solution Approach 1:
The circuit substrate is designed with localized transparent regions positioned to allow light extraction from LED chips while maintaining opaque or conductive regions for electrical connections. This spatial differentiation resolves the contradiction between light transmission and electrical conductivity requirements
Solution Approach 2:
A transparent conductive material is used in the light-transmitting region of the electrode pad, serving as an intermediary that simultaneously provides both electrical conductivity and optical transparency. This material allows light to pass through while maintaining the electrical connection function
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 enhances the light extraction efficiency from the circuit substrate side, enabling the LED display to emit light on both sides and maintain high brightness and reliability.
Implementation Method 1
The first electrode pad comprises a first light transmission region that transmits light emitted from the LED chip
Data Source
AI summary
A display device includes a circuit substrate comprising a first electrode pad and an LED chip comprising a first electrode bump that is electrically connected to the first electrode pad, and at least emitting light in a direction of the circuit substrate. The first electrode pad comprises a first light transmission region that transmits light emitted from the LED chip.