SMD LED Light Extraction via Ion-Beam Etched Surface Irregularities
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Solution Overview
Problem
Conventional SMD-type LEDs experience reduced light efficiency due to internal total reflection at the interface between the molding material and air, leading to decreased luminance, and existing solutions like attaching a hemispheric lens increase the device height, manufacturing costs, and complexity.
Innovation Solution
Forming surface irregularities on the molding material using an ion-beam etching process with argon ions to increase the critical angle of light incidence, minimizing total reflection and enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a hemispheric lens is attached to the surface of the molding material, then light extraction efficiency is improved, but device height increases
Solution Approach 1:
The patent applies spheroidality by forming a hemispheric lens structure on the molding material surface. The curved spherical surface of the lens modifies light propagation paths, reducing internal total reflection and improving light extraction efficiency while integrating seamlessly with the package structure
Solution Approach 2:
The hemispheric lens is pre-formed as an integral part of the molding material through injection molding, rather than being attached as a separate component. This preliminary integration eliminates the need for additional bonding layers and reduces the overall device height while maintaining the light extraction benefits
2Loss of energy
If a hemispheric lens is attached to the surface of the molding material, then light extraction efficiency is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the hemispheric lens function with the molding material itself by incorporating the lens structure directly into the injection molding process. This consolidation eliminates separate lens components, bonding layers, and assembly steps, thereby reducing manufacturing complexity and cost while achieving the same light extraction improvement
Solution Approach 2:
The molding material serves multiple functions: it provides structural support, protects internal components, and simultaneously forms the hemispheric lens for light extraction enhancement. This multi-functionality reduces the number of separate components and simplifies the manufacturing process
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 surface irregularities effectively reduce internal total reflection, enhancing light extraction efficiency while maintaining a compact form factor and reducing manufacturing complexity and costs.
Implementation Method 1
forming surface irregularities on the molding material using an ion-beam etching process with argon ions
Implementation Method 2
internal total reflection at the interface between the molding material and air
Implementation Method 3
increase the critical angle of light incidence
Data Source
AI summary
A surface mounting device-type light emitting diode (SMD-type LED) comprises a lead frame composed of a pair of lead terminals; a package housing a portion of the lead frame therein, the package having an emission window which is opened so that light is emitted through the emission window; an LED chip mounted on the lead frame inside the package; a wire for electrically connecting the LED chip and the lead frame; and a molding material filled in the package, the molding material having surface irregularities with a predetermined shape formed on the surface thereof which is exposed through the emission window of the package.