Elevated LED Package Structure for Radial Light Extraction
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Solution Overview
Problem
Conventional light emitting device packages suffer from reduced light extraction efficiency due to light being captured in cavities and structural limitations that prevent emission in directions other than vertical, leading to potential molding part breakage under high current conditions.
Innovation Solution
The design includes a light emitting device package with a molding member having a molding groove and a dam structure that allows the light emitting device chip to be positioned above the package body, enabling light emission in all directions and preventing molding part breakage by avoiding cavity capture and using a low-viscosity molding member with a specific radius of curvature for improved light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting device chip is disposed in the cavity, then the package structure is compact, but light extraction efficiency is reduced due to light capture in the cavity
Solution Approach 1:
The patent inverts the conventional approach by disposing the light emitting device chip above the package body rather than inside the cavity. This inversion eliminates light capture in the cavity while maintaining package compactness through the elevated chip position and optimized molding member geometry.
Solution Approach 2:
The patent transitions from a two-dimensional cavity-based structure to a three-dimensional elevated structure with the chip positioned above the package body. This dimensional change allows light to emit in multiple directions including radial directions, improving light extraction efficiency while maintaining compact packaging.
2Illumination intensity
If high current is supplied to the light emitting device chip, then light output is increased, but the molding part may be broken
Solution Approach 1:
The patent applies beforehand cushioning by designing the molding member with optimized geometry including a specific radius of curvature (R1) and height (h1) that are predetermined to withstand high current conditions. This preventive design ensures the molding part maintains integrity even when high current is supplied to the light emitting device chip.
3Device complexity
If the light emitting device chip is captured in the cavity, then the package structure is simplified, but light emission in directions other than vertical is prevented
Solution Approach 1:
The patent inverts the conventional cavity-based structure by positioning the chip above the package body. This inversion naturally enables light emission in radial directions including oblique and horizontal directions, providing versatile light emission patterns while maintaining relatively simple package structure through the elevated chip configuration.
4Illumination intensity
If a low-viscosity molding member is used, then light extraction is improved, but structural support may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity of the molding member within a specific range (0.1 to 10 Pa·s at 25°C) and configuring its geometric parameters including radius of curvature (R1: 0.5 to 2.0 mm) and height (h1: 0.2 to 1.0 mm). These parameter optimizations ensure the molding member provides adequate structural support while maintaining low viscosity for improved light extraction efficiency.
Data Source
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AI summary
A disclosed light emitting device package includes a package body, a light emitting device chip disposed on a chip mount area of the package body, and a molding member disposed on the package body, wherein the package body includes a central area having the chip mount area and a chip non-mount area adjacent to the chip mount area, the molding member being disposed on the central area, and a peripheral area around the central area, and wherein an upper surface of the light emitting device chip is higher than an upper surface of the package body in the chip non-mount area and than an upper surface of the package body in the peripheral area.