Resin Package Lead Grooves for Light Extraction
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Solution Overview
Problem
In light emitting devices, the reflection layer may not be sufficiently filled during the molding process, leading to a lack of the resin frame, which can result in inadequate light extraction efficiency and reliability.
Innovation Solution
The design includes a resin package with a light reflective member and a specific configuration of leads and resin portions, such as notches and grooves, to ensure complete filling of the resin material and prevent the reflection layer from covering the lateral surfaces of the light emitting elements, enhancing adhesion and light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the resin portion and resin frame are integrally molded by a molding method, then manufacturing efficiency is improved, but a part of the region that is to be the resin frame may not be sufficiently filled with resin material, leading to lack of a portion of the resin frame
Solution Approach 1:
The resin body is divided into multiple portions (first resin portion, second resin portion, third resin portion) that are formed in different mold cavities. The first resin portion is formed in a first mold cavity, the second resin portion is formed in a second mold cavity, and the third resin portion is formed in a third mold cavity. This segmentation allows each portion to be independently molded with optimized filling, ensuring complete resin frame formation while maintaining integral molding efficiency.
2Illumination intensity
If a resin frame is disposed around the light emitting element to prevent the reflection layer from covering the lateral surfaces, then light extraction efficiency is improved, but the resin frame may be insufficiently filled during molding
Solution Approach 1:
The resin body is segmented into multiple portions formed in different mold cavities, allowing the resin frame to be completely and reliably formed around the light emitting element without insufficient filling, while still providing the necessary light extraction efficiency by preventing the reflection layer from covering the lateral surfaces.
Solution Approach 2:
Different portions of the resin body have different local qualities and functions. The first resin portion forms the outer lateral surface, the second resin portion surrounds the element mounting region, and the third resin portion is disposed between leads. This local differentiation ensures that each region has the appropriate properties for its specific function, including complete filling and proper adhesion.
3Strength
If grooves are formed in the lead to enhance adhesion between resin and lead, then bonding strength is improved, but device complexity increases
Solution Approach 1:
Grooves are formed locally in specific regions of the lead (first groove in the upper surface, second groove connecting with the notch) rather than throughout the entire lead structure. This localized approach enhances adhesion between the resin and lead at critical bonding interfaces while minimizing the increase in overall device complexity.
Solution Approach 2:
The grooves and notches are pre-formed in the lead before the resin molding process. This preliminary action prepares the lead surface in advance to enhance adhesion, allowing the resin to properly bond during the molding process without requiring additional complex structural modifications.
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
This configuration ensures a highly reliable light emitting device with improved light extraction efficiency by preventing resin frame deficiencies and enhancing the adhesion between the resin body and leads, allowing for efficient heat dissipation and light emission.
Implementation Method 1
The light reflecting member disposed in the recess at a portion between the inner wall surface and the second resin portion
Implementation Method 2
enhancing adhesion between the resin body and leads
Data Source
AI summary
A light emitting device includes: a resin package including: a first lead including: at least one notch extending from an upper surface of the first lead to a lower surface of the first lead, a first groove formed in the upper surface of the first lead, and at least one second groove connecting the first groove with the at least one notch, and a second lead, and a resin body including: a first resin portion, a second resin portion, a part of the second resin portion being disposed in the first groove, a third resin portion disposed between the first lead and the second lead, and a first resin connecting portion connecting the first resin portion with the second resin portion, at least a part of the first resin connecting portion being disposed in the at least one second groove; a light emitting element; and a light reflecting member.