LED Package Reflector Geometry for Wider Directivity Angle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light-emitting device packages for edge-type backlight units suffer from color shading due to their narrow directivity angle, and reducing the package intervals to increase the number of packages raises costs.
Innovation Solution
A light-emitting device package design that increases the directivity angle by exposing a side surface of a wavelength conversion member, featuring a frame with electrodes, an LED chip, a reflective member with differing side heights, and a wavelength conversion member to enhance light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the number of light-emitting device packages is increased to reduce color shading, then color uniformity is improved, but manufacturing cost increases
Solution Approach 1:
The reflective member is designed with different heights at different locations (first height at first side, second height at second side), creating local variations in light reflection characteristics. This allows different regions to optimize light extraction and distribution, improving color uniformity without requiring increased package density
Solution Approach 2:
The reflective member employs an asymmetric structure where the first side extends to a first height and the second side extends to a second height, breaking the symmetry of conventional reflective members. This asymmetric design optimizes light extraction in specific directions, enhancing color uniformity while maintaining cost-effective manufacturing
2Illumination intensity
If the directivity angle is increased to improve light distribution, then color shading is reduced, but light extraction efficiency decreases
Solution Approach 1:
Different regions of the reflective member are designed with different heights to perform specialized functions: the first side at first height optimizes for light extraction efficiency, while the second side at second height optimizes for directivity angle and light distribution, resolving the trade-off between these two parameters
Solution Approach 2:
The reflective member utilizes vertical dimension variations (different heights) to control light propagation in multiple directions. By introducing height as an additional degree of freedom, the design achieves improved directivity angle and color distribution without sacrificing 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
The design effectively increases the directivity angle and light efficiency, reducing color shading and costs associated with increasing package density, while maintaining the structural integrity and functionality of the light-emitting device package.
Implementation Method 1
a reflective member disposed on the frame, forming a cavity for accommodating the LED chip therein, and reflecting light emitted from the LED chip
Implementation Method 2
a wavelength conversion member filled in the cavity to cover the LED chip
Data Source
AI summary
A light-emitting device package includes a frame including one side on which a first electrode is formed and the other side on which a second electrode is formed, an LED chip including a first conductive connection pad electrically connected to the first electrode and a second conductive connection pad electrically connected to the second electrode, a reflective member disposed on the frame, forming a cavity for accommodating the LED chip therein, and reflecting light emitted from the LED chip, and a wavelength conversion member filled in the cavity to cover the LED chip, wherein the reflective member includes a first side and a second side different from the first side, and a first height of the first side and a second height of the second side are formed to be different from each other.