White Resin Reflective Surface Area for LED Light Extraction
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Solution Overview
Problem
Conventional light emitting devices face issues with reliability and longevity, especially in high temperature environments, due to degradation of reflective surfaces and insufficient adhesive strength when using thermosetting resins, which also result in reduced light extraction efficiency and increased burr generation during molding.
Innovation Solution
A light emitting device with a white resin molding package integrally molded with lead frames, where the area of the white resin surface on a reflective surface is larger than the lead frame and light emitting element surfaces, and a step section is formed on the lead frames to increase the reflective area and improve adhesion, enhancing light extraction efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermosetting resin is used for the reflective resin material to improve light-resistance and weather-resistance, then reliability is improved, but adhesive strength decreases and moldability worsens
Solution Approach 1:
The patent applies different resin materials to different functional regions: thermosetting resin is used specifically in the reflective resin material 103 where light-resistance and weather-resistance are critical, while thermoplastic resin is used in the lens resin material 104 where moldability and adhesive strength are more important. This local differentiation allows each region to have optimized properties for its specific function.
Solution Approach 2:
The patent uses a composite structure combining thermosetting resin and thermoplastic resin in different components of the light emitting device. The thermosetting resin provides durability and light-resistance in the reflective portion, while the thermoplastic resin provides good adhesion and moldability in the lens portion, achieving overall system optimization through material composition.
2Reliability
If thermosetting resin is used for the reflective resin material to improve light-resistance, then reliability is improved, but moldability worsens resulting in higher burr generation
Solution Approach 1:
The patent localizes the use of thermosetting resin to only the reflective resin material 103 where light-resistance is required, while using thermoplastic resin for the lens resin material 104 where easy molding is needed. This spatial differentiation of material properties resolves the contradiction between reliability and ease of manufacture.
Solution Approach 2:
The patent segments the resin material into two distinct components: reflective resin material 103 and lens resin material 104. Each segment uses a different resin type optimized for its specific function, allowing the reflective portion to have high light-resistance while the lens portion maintains good moldability, thus resolving the manufacturing contradiction.
3Reliability
If the metallic lead frame surface is used as the reflective surface to improve electrical conductivity, then electrical performance is improved, but light extraction efficiency decreases due to degradation upon blasting process
Solution Approach 1:
The patent merges the reflective function with the resin material 103 by incorporating reflective particles into the resin, creating a composite reflective resin material. This allows the lead frame to maintain its electrical conductivity function while the resin provides the reflective function, eliminating the conflict between electrical performance and light extraction efficiency.
Solution Approach 2:
The resin material 103 acts as an intermediary between the lead frame and the light extraction requirement. The reflective particles embedded in the resin create a reflective surface that does not undergo blasting degradation, while the lead frame beneath maintains electrical connectivity. This intermediary layer resolves the contradiction between maintaining electrical conductivity and achieving high light extraction efficiency.
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 improves light extraction efficiency and reliability by increasing the reflective area with high reflectivity white resin and enhancing adhesive strength, while maintaining even surfaces and reducing burr generation, thus addressing the limitations of conventional devices.
Implementation Method 1
a reflective resin material 103, characterized in that an area in a plane view of a white resin surface on a reflective surface that is level with a mounting surface of a light emitting element 102 is larger than an area in a plane view occupied by surfaces of a lead frame 101 and the light emitting element 102
Data Source
AI summary
Improves light extraction efficiency. A light emitting device 1 using a white resin molding package 5 integrally molded with lead frames 3, 4 constituting an electrode corresponding to one or a plurality of light emitting element 2 and white resin, wherein an area in a plane view of a white resin surface on a reflective surface that is level with amounting surface of the light emitting element 2 is configured to be larger than total area in a plane view occupied by surfaces of the lead frames 3, 4 and the light emitting element. Further, a step section is formed on the surfaces of lead frames 3, 4, white resin is filled in the step section, and the area of white resin surface on a reflective surface where the light emitting element 2 is mounted is increased.