LED Package Layout With Reflective Filler for Light Extraction
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Solution Overview
Problem
Conventional light emitting devices face challenges with light extraction efficiency due to absorption losses in metal reflecting films, conductive members, and sealing materials, particularly with materials prone to sulfuration or halogenation, which reduce reflectance and lead to discoloration, and issues with moldability of highly-reflective resin layers, as well as absorption by conductive bumps and leads.
Innovation Solution
A light emitting device design where at least a portion of the side surfaces and upper surface of the transparent substrate are exposed to minimize absorption by reflective members, and an insulating filler with high reflectance is applied to cover electrically conductive members, reducing absorption losses and improving light extraction efficiency without the need for high-reflectance materials, while maintaining stability and preventing deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a metal reflecting film with high reflectance is applied on the electrically conductive member, then light extraction efficiency is improved, but the material is prone to sulfuration or halogenation causing discoloration and reduced reflectance over time
Solution Approach 1:
The patent applies a composite material structure consisting of a reflective member (metal layer with high reflectance) combined with an insulating filler layer (white pigment-containing material). This composite structure allows the reflective member to provide high light extraction efficiency while the insulating filler layer protects it from sulfuration and halogenation, preventing discoloration and maintaining stability over time.
2Loss of energy
If a highly-reflective resin layer is applied to suppress absorption loss, then light extraction efficiency is improved, but the moldability deteriorates
Solution Approach 1:
The patent applies the insulating filler material selectively only to portions of the electrically conductive member that do not have light emitting elements mounted thereon. This local application approach allows the reflective properties to be enhanced where needed while avoiding interference with the moldability and assembly process of the overall device.
3Loss of energy
If the surface area of electrically conductive members is reduced to minimize absorption loss, then light extraction efficiency is improved, but the electrical conductivity and current supply capability deteriorate
Solution Approach 1:
The patent introduces an insulating filler material as an intermediary substance that is applied to the electrically conductive member. This filler material acts as a mediator that reflects light to reduce absorption loss while simultaneously serving as an insulating layer that does not interfere with the electrical conductivity function of the underlying conductive member.
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 solution enhances light extraction efficiency, maintains high reliability by preventing deterioration of components, and ensures uniform color distribution, achieving higher optical output power while maintaining cost-effectiveness.
Implementation Method 1
an insulating filler with high reflectance is applied to cover electrically conductive members, reducing absorption losses and improving light extraction efficiency
Implementation Method 2
at least a portion of the side surfaces and upper surface of the transparent substrate are exposed to minimize absorption by reflective members
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A light emitting device (100) includes a base member (101), electrically conductive members (102a, 102b) disposed on the base member (101), a light emitting element (104) mounted on the electrically conductive members (102a, 102b), an insulating filler (114) covering at least a portion of surfaces of the electrically conductive members (102a, 102b) where the light emitting element (104) is not mounted, and a light transmissive member (108) covering the light emitting element (104).