Light-Emitting Device with Reflective Metal Member
Solution Overview
Problem
Existing light-emitting devices face challenges in achieving high light extraction efficiency due to light absorption by transparent electrodes and insulating films.
Innovation Solution
A light-emitting device configuration featuring a semiconductor layered structure with a conductive substrate, upper electrodes, a lower electrode spaced apart from the semiconductor layered structure, and conduction prevention portions comprising a light-reflective metal member and an insulating member on the lower surface, which prevents electrical connection and enhances light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent electrode and transparent insulating film are used in the light-emitting device, then electrical connection and insulation are achieved, but light extraction efficiency deteriorates due to light absorption by these components
Solution Approach 1:
The device structure is segmented into distinct functional regions: a light-emitting region with upper electrodes, and a light-reflecting region with lower electrodes and reflective films. This segmentation allows light to be directed upward through the transparent substrate while electrical connections are maintained through the lower electrodes, reducing light absorption losses in insulating films.
Solution Approach 2:
The patent transitions from a planar configuration to a three-dimensional structure by positioning upper and lower electrodes at different vertical levels and introducing reflective films at angled orientations. This dimensional change enables light to be reflected upward at optimal angles while maintaining electrical connectivity, thereby improving light extraction efficiency without compromising electrical function.
2Ease of manufacture
If transparent materials are used for electrodes and insulating films, then electrical functionality is maintained, but light absorption increases reducing overall device performance
Solution Approach 1:
Different regions of the device are assigned different material properties: the light-emitting region uses transparent materials for electrical connectivity, while the light-reflecting region employs highly reflective metallic films. This local differentiation optimizes each region's function - transparency where electrical conduction is needed, and reflectivity where light direction is critical - thereby improving overall light emission efficiency.
3Device complexity
If conventional electrode arrangements are used, then device structure is simple, but light extraction efficiency is limited due to absorption by transparent components
Solution Approach 1:
Reflective films are positioned in advance in the light-reflecting region below the semiconductor layer. These pre-positioned reflective surfaces are designed to intercept and redirect light that would otherwise be absorbed by transparent insulating films or electrodes, thereby preemptively preventing energy loss before it occurs and improving overall light extraction 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
This configuration improves light extraction efficiency by efficiently reflecting light from the semiconductor layered structure, increasing the light-emitting area and reducing absorption, thereby enhancing the overall performance of the light-emitting device.
Implementation Method 1
Each of the one or more conduction prevention portions includes a metal member having light reflectivity and arranged on the lower surface of the semiconductor layered structure
Data Source
AI summary
A light-emitting device includes: a semiconductor layered structure; a conductive substrate disposed under the semiconductor layered structure; one or more upper electrodes each disposed on a portion of an upper surface of the semiconductor layered structure; a lower electrode disposed on a lower surface of the semiconductor layered structure; one or more metal members each having light reflectivity and disposed on the lower surface of the semiconductor layered structure in a region between (i) a region directly under a respective one of the one or more the upper electrodes and (ii) the region on which the lower electrode is disposed; one or more first insulating members each disposed on the lower surface of the semiconductor layered structure in the region directly under the respective one of the one or more the upper electrodes; and one or more second insulating members on a lower surface of the metal member.