LED Light Extraction Pattern Period Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In white LED devices, a significant portion of light is lost due to reentry into the chip, leading to reduced efficiency and reliability, primarily because of absorption losses and refractive index differences between the encapsulant and air, as well as the self-emitting process of phosphor-converted light.
Innovation Solution
A light extraction pattern with a period exceeding λ/n, where λ is the wavelength of light and n is the refractive index, is implemented on the light emitting structure to prevent reentry of light into the chip, enhancing light extraction efficiency and reliability by acting as an anti-reflection coating and diffraction structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a light extraction structure is provided on the chip surface to improve light extraction efficiency, then light extraction efficiency is improved, but light reentry into the chip increases causing absorption loss and reduced reliability
Solution Approach 1:
The patent applies different structural characteristics to different regions of the light extraction surface. By creating localized patterns with specific period ranges (50-200 nm), the structure achieves optimal light extraction in certain directions while preventing light reentry into the chip, thus resolving the contradiction between extraction efficiency and reliability
Solution Approach 2:
The patent optimizes the period parameter of the light extraction structure to fall within a specific range (50-200 nm). This parameter optimization enables the structure to effectively extract light while preventing reentry, thereby improving both light extraction efficiency and chip reliability simultaneously
2Productivity
If the period of the light extraction pattern is reduced to improve light extraction, then light extraction efficiency increases, but light reentry is not effectively prevented
Solution Approach 1:
The patent identifies and optimizes the period parameter of the light extraction pattern to a specific range (50-200 nm). This parameter optimization creates the optimal balance between light extraction efficiency and preventing light reentry, thereby minimizing energy loss while maximizing extraction performance
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 light extraction pattern effectively maintains light extraction efficiency within the desired range, preventing light reentry and improving the overall efficiency and reliability of white LEDs by optimizing light extraction and reducing absorption losses.
Implementation Method 1
A light extraction pattern in which a period (a) exceeds λ/n (where, λ is a wavelength of light emitted from the active layer, and n is a refractive index of the light emitting structure) may be disposed on the light emitting structure
Implementation Method 2
A light extraction pattern in which a period (a) exceeds λ/n (where, λ is a wavelength of light emitted from the active layer, and n is a refractive index of the light emitting structure) may be disposed on the light emitting structure to prevent reentry of light into the chip
Data Source
Figure 1~2a
Figure 2b
Figure 3
AI summary
Provided are a light emitting diode, (100,102,103) a light emitting diode package (200), and a lighting system (1100,1200). The light emitting diode includes a light emitting structure (120) including a first conductive type semiconductor layer (122), a second conductive type semiconductor layer (126), and an active layer (124) between the first conductive type semiconductor layer and the second conductive type semiconductor layer and a light extraction pattern (P) in which a period (a) exceeds λ/n (where, λ, is a wavelength of light emitted from the active layer, and n is a refractive index of the light emitting structure) on the light emitting structure. The period (a) may be in the range of 5×(λ/n) < a < 15×(λ/n). An etching depth (h) of the light extraction pattern (P) may be equal to or greater than λ/n.