Light Source Package Coating for Current Distribution
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Solution Overview
Problem
Conventional light source package structures, such as TO-CAN packages, face challenges in meeting modern requirements due to inadequate light current distribution convergence, primarily caused by variations in surface roughness and die-bonding adhesive layer occupancy, leading to inconsistent light reflection and absorption.
Innovation Solution
The implementation of a light source package structure that includes a light absorbing layer or a high reflectance coating layer to address the light current distribution issues by absorbing or reflecting light, thereby reducing the impact of surface roughness and adhesive layer variations, using materials like composite resin or silicone resin with specific properties for the light absorbing layer and a mixture of resin and light reflecting particles for the high reflectance coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional TO-CAN package structure is used, then manufacturing simplicity is maintained, but light current distribution convergence is insufficient
Solution Approach 1:
A coating layer is introduced as an intermediary between the light emitting unit and the surrounding wall. This coating layer mediates the light interaction by providing controlled reflection or absorption properties, thereby converging the light current distribution without fundamentally changing the TO-CAN package structure
Solution Approach 2:
The optical parameters of the package structure are changed by applying a coating layer with specific optical properties (reflective or absorptive). This changes the light reflection and absorption characteristics, improving light current distribution convergence while maintaining the basic structure
2Reliability
If surface roughness and die-bonding adhesive layer variations are present, then manufacturing ease is maintained, but light reflection and absorption consistency deteriorates
Solution Approach 1:
The coating layer serves as an intermediary that compensates for surface roughness and adhesive layer variations. By providing a controlled optical interface, it reduces the impact of manufacturing variations on light reflection and absorption consistency
Solution Approach 2:
The coating layer is applied beforehand to create a uniform optical interface that cushions against the effects of subsequent manufacturing variations in surface roughness and adhesive layer thickness, ensuring consistent optical performance
3Manufacturing precision
If light reflecting particles are added to coating layer, then light current convergence is improved, but manufacturing complexity increases
Solution Approach 1:
The coating layer is formulated as a composite material containing resin and light reflecting particles. This composite structure provides the desired optical properties for light current convergence while allowing for standardized manufacturing processes
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 absorbing layer and high reflectance coating layer effectively converge light current distribution, reducing variations by up to 51.1% and increasing light current by 16.5% on average, while also improving reliability by shielding light reflection surfaces and preventing silver ion migration in high temperature and humidity environments.
Implementation Method 1
a light absorbing layer or a high reflectance coating layer to address the light current distribution issues by absorbing or reflecting light
Implementation Method 2
a light absorbing layer or a high reflectance coating layer to address the light current distribution issues by absorbing or reflecting light
Data Source
AI summary
A light source package structure is provided. The light source package structure includes a substrate, an upper electrode layer, a light emitting unit, a photodiode, a surrounding wall, a light permeable element, and a coating layer. The substrate includes a first surface and a second surface that is opposite to the first surface. The upper electrode layer is disposed on the first surface of the substrate. The light emitting unit and the photodiode both are disposed on the upper electrode layer. The surrounding wall is disposed on the first surface and is arranged to surround the light emitting unit and the photodiode. The light permeable element is disposed on the surrounding wall. The coating layer is disposed inside of the surrounding wall and is coated on a part of the first surface and a part of the upper electrode layer.