LED Package Light-Altering Coatings for Lead Frame Reflection Control
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Solution Overview
Problem
Conventional LED packages face challenges in achieving high light emission efficiency due to internal reflection and potential discoloration of lead frame structures, which can lead to reduced light output and non-uniformity.
Innovation Solution
The use of light-altering coatings that cover exposed portions of lead frame structures within package recesses, configured to reflect light emissions and reduce the impact of lead frame discoloration, while also being arranged in contact with or spaced from LED chips to optimize light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light emissions from LED chips are allowed to interact with lead frame structures, then mechanical support and electrical connections are provided, but internal reflection increases and light emission efficiency decreases
Solution Approach 1:
A light-altering coating is applied to the lead frame structure to act as an intermediary between the LED chip and the lead frame. This coating modifies the optical interaction by reducing internal reflection and preventing harmful light absorption, while the lead frame continues to provide mechanical support and electrical connections. The coating serves as a mediating layer that resolves the conflict between structural functionality and optical performance.
2Illumination intensity
If lead frame structures are exposed within package recesses, then mechanical support is provided, but discoloration occurs due to environmental exposure reducing light output quality
Solution Approach 1:
A light-altering coating in the form of a thin film is applied to the exposed portions of the lead frame structure within the package recess. This thin film protective layer prevents environmental exposure and discoloration of the underlying lead frame, while maintaining the mechanical support function. The coating acts as a protective barrier that preserves both the structural integrity and optical performance over time.
3Loss of energy
If light-altering coatings cover lead frame structures, then internal reflection is reduced and light emission efficiency improves, but device complexity increases
Solution Approach 1:
The light-altering coating serves multiple functions simultaneously: it reduces internal reflection to improve light extraction efficiency, protects the lead frame from environmental discoloration, and maintains mechanical support functionality. By combining these functions into a single coating layer, the solution avoids the need for separate components for each function, thereby limiting the increase in device complexity while achieving multiple benefits.
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 implementation of light-altering coatings enhances light emission efficiency by reducing internal reflection and minimizing the effects of lead frame discoloration, resulting in improved brightness and uniformity of light output.
Implementation Method 1
such light-altering coatings may be configured to reflect light emissions from LED chips before such light emissions reach portions of lead frame structures
Implementation Method 2
Light emissions that exit surfaces of LED emitters typically interact with various elements or surfaces of the LED package and lumiphoric materials before exiting, thereby increasing opportunities for light loss
Data Source
AI summary
Light-emitting diode (LED) packages, and more particularly arrangements of light-altering coatings in LED packages are disclosed. Exemplary LED packages may include lead frame structures that are at least partially encased by a housing. Arrangements of light-altering coatings may be provided that cover one or more portions of lead frame structures exposed within LED package recesses. By providing light-altering coatings that cover lead frame structures within package recesses, negative impacts from potential lead frame discoloration due to environmental exposure may be reduced. Additionally, such light-altering coatings may be configured to reflect light emissions from LED chips before reaching portions of lead frame structures. Light-altering coating arrangements are disclosed where light-altering coatings are arranged in contact with LED chips or, alternatively, in a spaced relationship with LED chips. Retention structures are disclosed that may define boundaries of light-altering coatings along recess floors of corresponding LED packages.