LED Array Pad Electrode Layout for Current Spreading and Light Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor light emitting devices face challenges in achieving reliable light emission due to light absorption by metal electrodes and poor current diffusion between connected LEDs, particularly in high-voltage chip structures, which affects integration and manufacturing reliability.
Innovation Solution
A semiconductor light emitting device configuration with a first and second array of light emitting units on a substrate, where each unit includes a first and second semiconductor layer with an active layer for electron and hole recombination, and pad electrodes that cover multiple units to improve electrical connections and reduce light absorption, along with insulating layers and upper electrodes for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If metal reflective films (electrodes 901, 902, 903) are used to achieve high reflectance and current spreading, then light absorption by metal needs to be overcome, but current diffusion is improved
Solution Approach 1:
The patent introduces a light transmitting conductive film (600) as an intermediary between the metal reflective film (904) and the active layer. This intermediary layer allows light to pass through while enabling current diffusion, thus reducing light absorption loss by the metal film while maintaining good current diffusion properties
Solution Approach 2:
The patent employs a composite structure combining a light transmitting conductive film with metal reflective films. This composite configuration allows the system to simultaneously achieve low light absorption (through the transparent conductive film) and good current diffusion (through the metal reflective film properties)
2Loss of energy
If DBR and metal reflective film are provided to reduce light absorption by metal reflective film, then light absorption is reduced, but current diffusion is relatively poor
Solution Approach 1:
The patent merges the functions of the DBR (distributed Bragg reflector) and metal reflective film into a unified reflective structure. By combining these two reflective elements, the patent achieves both reduced light absorption and improved current diffusion, as the merged structure provides both optical reflection and electrical conduction pathways
3Reliability
If interconnector is deposited to connect p-side electrode and n-side electrode of neighboring LEDs, then electrical connection is achieved, but etch depth is large and step height is large
Solution Approach 1:
The patent transitions from planar interconnection to three-dimensional stacked interconnection. By forming pad electrodes that extend vertically across multiple light emitting units and connecting them in the vertical dimension, the patent achieves electrical connection between neighboring LEDs while avoiding the need for deep lateral etching and large step heights
4Reliability
If pad electrode covers multiple light emitting units, then electrical connection is improved and light absorption is reduced, but manufacturing precision is required
Solution Approach 1:
The pad electrode is designed to serve multiple functions simultaneously: it provides electrical connection for multiple light emitting units, acts as a reflective element, and serves as a bonding interface. This multi-functionality reduces the need for separate components and simplifies the manufacturing process, thereby reducing the required manufacturing precision
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 reliability of light emission by reducing light absorption and improving current diffusion, thereby mitigating defects and weak lighting issues in high-voltage chip structures, and facilitates better integration of light emitting units.
Implementation Method 1
an active layer 40 interposed between the first semiconductor layer 30 and the second semiconductor layer 50 for generating light by recombination of electrons and holes
Data Source
AI summary
The present invention relates to a semiconductor light emitting device, and more particularly, to a light emitting device with an increased reliability in light emitting areas in the manufacture of multiple light emitting units that are electrically connected to each other. In the semiconductor light emitting device according to the present invention, at least one of the first upper electrode or the second upper electrode is configured to be electrically connected to the first pad electrode or the second pad electrode, respectively, at least partially on the upper portions of the respective light emitting units that are at least partially covered by the first pad electrode or the second pad electrode.