Semiconductor Light-Emitting Device Bump-Protrusion Scattering
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Solution Overview
Problem
Semiconductor light-emitting devices suffer from low light-extraction efficiency due to internal total reflection, where light beams are absorbed instead of being emitted outside the device.
Innovation Solution
The device features a substrate with periodic bumps and a first conductive type semiconductor layer having protrusions positioned in a ring manner at the peripheral region, spaced apart from the bumps, which scatter and diffract light beams to improve extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a transparent electrode and reflection layer are used to guide light beams, then light extraction efficiency is improved, but internal total reflection still causes light beams to be absorbed instead of propagating outside the device
Solution Approach 1:
The invention introduces undulations (curved surface structures) on the interface between the substrate and the first semiconductor layer. These undulations scatter light beams that would otherwise undergo total internal reflection, redirecting them toward the device exterior. The curved interface modifies the optical path of light beams, enabling escape from the high-reflection environment.
Solution Approach 2:
The undulated structure is specifically positioned at the substrate-semiconductor interface in peripheral regions, creating localized optical modification where it is most needed. This local structural variation targets the specific problem area (where total internal reflection occurs most frequently) without altering the entire device structure.
2Loss of energy
If light beams are reflected internally due to total reflection effect, then light beams are absorbed by the light-emitting layer, but adding more reflection layers increases device complexity
Solution Approach 1:
The undulated interface provides a passive, geometry-based solution to reduce total internal reflection. By creating a curved interface, the patent eliminates the need for additional active components or complex multi-layer structures that would otherwise be required to manage light extraction.
Solution Approach 2:
The undulated structure utilizes the existing substrate and semiconductor layer materials to achieve light scattering. The interface itself becomes the functional element that redirects light, eliminating the need for separate light-management components and reducing overall device complexity.
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 significantly reduces internal total reflection, preventing light absorption and enhancing light extraction efficiency by directing light beams outside the device.
Implementation Method 1
The protrusions are spaced apart from the bumps and facing a portion of the substrate between the bumps... scatter and diffract light beams to improve extraction efficiency
Implementation Method 2
The protrusions are spaced apart from the bumps and facing a portion of the substrate between the bumps... scatter and diffract light beams to improve extraction efficiency
Implementation Method 3
a portion of the light beams are reflected internally into the light-emitting device due to the total reflection effect... This configuration significantly reduces internal total reflection
Data Source
AI summary
A semiconductor light-emitting device includes a substrate having an upper surface and a plurality of bumps positioned on the upper surface in a periodic manner, a first conductive type semiconductor layer positioned on the substrate, a light-emitting structure positioned on the first conductive type semiconductor layer, and a second conductive type semiconductor layer positioned on the light-emitting structure. The first conductive type semiconductor layer includes a plurality of protrusions each facing a portion of the substrate between the bumps, the protrusions are positioned in a ring manner at a peripheral region of the first conductive type semiconductor layer, and the protrusions are spaced apart from the bumps.