Light Emitting Device Electrode Segmentation
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Solution Overview
Problem
Conventional light emitting devices with narrow electrodes face issues of burnout under high current due to small cross-section and reduced light efficiency when attempting to prevent burnout by increasing electrode width, leading to light absorption at the ohmic contact.
Innovation Solution
A light emitting device design featuring a semiconductor multilayer structure with a surface center electrode and narrow electrodes, where the surface center electrode reflects light and the narrow electrodes have a current feeding part and a light reflecting part with a higher resistivity transmitting layer to minimize light absorption and prevent burnout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the narrow electrode width is increased to prevent burnout, then the electrode reliability improves, but the light emitting efficiency deteriorates due to light absorption by the ohmic contact part
Solution Approach 1:
The electrode structure is divided into two distinct parts: a narrow current feeding part for current supply and a wider light reflecting part for light extraction. This segmentation allows each part to be optimized independently - the narrow current feeding part minimizes light absorption while the wider light reflecting part provides sufficient current capacity and reflects light effectively, resolving the contradiction between burnout resistance and light efficiency
Solution Approach 2:
Different regions of the electrode are given different properties: the current feeding part has narrow width and high conductivity for current supply, while the light reflecting part has wider width and high reflectivity for light extraction. This local differentiation allows the electrode to simultaneously achieve burnout resistance through adequate current distribution and high light efficiency through minimized absorption in the critical current feeding region
2Loss of energy
If the narrow electrode width is kept small to maintain light efficiency, then the light emitting efficiency improves, but the electrode reliability deteriorates due to burnout risk under large current
Solution Approach 1:
The electrode is segmented into a narrow current feeding part that maintains small width for minimal light absorption and a wider light reflecting part that provides adequate current handling capacity. This segmentation resolves the contradiction by separating the light efficiency function from the current capacity function
Solution Approach 2:
The light reflecting part acts as an intermediary between the narrow current feeding part and the semiconductor substrate. It receives current from the narrow part, distributes it to reduce current density, and simultaneously reflects light back to the active layer, thereby protecting the narrow current feeding part from burnout while maintaining light efficiency
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
The design enhances light extraction efficiency and prevents electrode burnout under high current conditions while maintaining low light absorption, achieving high luminescence and efficient power usage.
Implementation Method 1
the light reflecting part reflects the light emitted from the active layer at an interface between the transmitting part and the narrow electrode metal layer
Implementation Method 2
the surface center electrode part may reflect the light at an interface between the transmitting layer and the surface center electrode part
Implementation Method 3
a transmitting layer for transmitting the light
Implementation Method 4
the light is absorbed by an ohmic contact part between the narrow electrode and the semiconductor
Data Source
AI summary
A light emitting device has a semiconductor multilayer structure having a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, a narrow electrode having a current feeding part provided on a region of a part above of the first semiconductor layer for supplying an electric current from outside to the semiconductor multilayer structure, and a narrow electrode provided adjacent to the current feeding part for reflecting a light emitted from the active layer, and a surface center electrode part electrically connected to the narrow electrode, and provided above the first semiconductor layer via a transmitting layer for transmitting the light.