LED Sealing Structure With Inclined Dam Resin for Light Extraction
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Solution Overview
Problem
Current light emitting devices face challenges in enhancing light emission efficiency, lifetime, and light distribution characteristics, particularly in the design and materials used for sealing and mounting light emitting elements.
Innovation Solution
A light emitting device design featuring a substrate with mounted light emitting elements, a dam resin with an inclined surface, and a seal resin, where the dam resin has a protruding portion and is formed from synthetic resin containing white particles, with a transparent resin between the light emitting element and the dam resin, and a conic solid resin extending along the bonding wire, optimizing the refractive indices and adhesiveness of the resins to improve light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal resin is used to seal the light emitting element, then the light emitting device can be protected and assembled, but the light emission efficiency and light distribution characteristics are compromised due to refractive index mismatch and stress on bonding wires
Solution Approach 1:
The sealing structure is divided into two distinct parts: a dam resin that surrounds the light emitting element and provides mechanical support, and a seal resin that fills the remaining space and provides sealing. This segmentation allows each material to be optimized for its specific function, with the dam resin having higher light transmittance to improve light emission efficiency while the seal resin provides reliable sealing.
Solution Approach 2:
The dam resin acts as an intermediary structure between the light emitting element and the external environment. It provides a transition zone that reduces stress on bonding wires through its inclined surface design, while also improving light extraction efficiency through optimized refractive index and light transmittance properties.
2Area of stationary object
If a white resin dam material is used to surround the light emitting element, then the light emission area ratio can be increased, but stress concentration occurs on bonding wires and adhesion reliability deteriorates
Solution Approach 1:
The dam resin features an inclined surface that transitions from the light emitting element to the surrounding area, creating a curved gradient structure rather than a sharp boundary. This curved design distributes stress more evenly across the bonding wires and improves adhesion reliability by eliminating stress concentration points.
Solution Approach 2:
The dam resin is designed with different properties in different regions: it has high light transmittance and optimized refractive index near the light emitting element to improve light extraction, while providing mechanical support and stress distribution in the surrounding areas. The inclined surface creates a gradient transition in material properties.
3Strength
If the dam resin is made opaque with white particles, then structural support and sealing are improved, but light extraction efficiency is reduced
Solution Approach 1:
The dam resin uses a transparent or translucent base material with optimized refractive index rather than an opaque white material. This parameter change in light transmittance allows the dam resin to provide structural support while simultaneously improving light extraction efficiency by reducing light absorption and scattering.
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 enhances light emission efficiency, extends the lifetime of the device, and improves light distribution characteristics by reducing stress on bonding wires and ensuring reliable adhesion, leading to improved optical properties and reduced color unevenness.
Implementation Method 1
the inner surface of the frame is a mirror surface and reflection efficiency may be improved by light emitted from the light emitting element being reflected from the inner surface of the frame
Implementation Method 2
optimizing the refractive indices and adhesiveness of the resins to improve light extraction efficiency
Data Source
AI summary
A light emitting device has a substrate having a rectangular planar shape, one or a plurality of light emitting elements mounted on the substrate, a dam resin having a frame-like planar shape, arranged so as to surround the light emitting element, and having an inclined surface whose height increases as its distance from the light emitting element increases, and a seal resin arranged in an area surrounded by the dam resin and which seals the light emitting element, and the dam resin has a protruding portion extending and protruding from at least one side toward the opposite side.