LED Cavity Depth Optimization for Light Extraction
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Solution Overview
Problem
Light emitting diodes (LEDs) experience reduced luminous efficiency due to light absorption and scattering within the LED package, resulting in lower light intensity compared to the LED chip.
Innovation Solution
A light emitting device with a cavity depth of 250 μm to 450 μm and inclined sidewalls is designed, along with a method for fabricating the device, which includes a package body, a light emitting element, and a molding member to minimize cavity depth and maximize light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cavity depth is increased to accommodate the light emitting device, then the device can be properly mounted, but light absorption and scattering increase, reducing luminous efficiency
Solution Approach 1:
The patent optimizes the cavity depth parameter to a specific range (250-450 μm) to balance device mounting requirements with light extraction efficiency. This parameter change resolves the contradiction by finding the optimal depth that accommodates the device while minimizing light loss.
Solution Approach 2:
The patent introduces asymmetric inclined sidewalls with different angles (first sidewall at a different angle than second sidewall) to optimize light extraction. This asymmetric design allows light to be directed more effectively, reducing scattering and absorption while maintaining proper device mounting.
2Loss of energy
If the cavity depth is reduced to minimize light loss, then luminous efficiency improves, but the device cannot be properly mounted
Solution Approach 1:
The patent establishes a minimum cavity depth parameter (250-450 μm) that is sufficient for device mounting while being as small as possible to reduce light loss. This parameter optimization resolves the contradiction by finding the smallest adequate depth.
Solution Approach 2:
The patent uses inclined sidewalls that change the geometric configuration of the cavity, effectively using angular dimensions to optimize light extraction without increasing vertical depth. This allows proper device mounting in a shallow cavity.
3Ease of manufacture
If conventional vertical sidewalls are used, then manufacturing is simpler, but light extraction efficiency is reduced due to scattering
Solution Approach 1:
The patent employs asymmetric inclined sidewalls with different angles to optimize light extraction efficiency. While slightly more complex than vertical walls, the inclination angles are designed to work with standard molding processes, balancing manufacturing ease with optical performance.
Solution Approach 2:
The patent specifies particular inclination angle parameters for the sidewalls that can be achieved through conventional injection molding techniques. By optimizing these angular parameters, the patent maintains ease of manufacture while significantly improving light extraction efficiency.
4Ease of operation
If the distance between the light emitting device and light guide panel is increased, then assembly is easier, but light intensity and luminous flux are reduced
Solution Approach 1:
The patent optimizes the distance parameter between the light emitting device and light guide panel to a minimum value that still allows for practical assembly. This parameter optimization ensures maximum light intensity while maintaining ease of assembly through the optimized cavity design.
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 increases light intensity and luminous flux by up to 30% and improves brightness characteristics by reducing light loss and optimizing the distance between the light emitting device and the light guide panel, enhancing the overall light extraction effect.
Implementation Method 1
Light emitting diodes (LEDs) can implement various colors using a light emitting source
Implementation Method 2
Light emitted from the LED chip mounted in the LED package is lost by light absorption and light scattering within the LED package
Implementation Method 3
Light emitted from the LED chip mounted in the LED package is lost by light absorption and light scattering within the LED package
Data Source
AI summary
Embodiments of a light emitting device and a method for fabricating the same are provided. The light emitting device comprises a cavity and one or more light emitting elements. The cavity is formed to a depth of 450 μm or less, and the light emitting elements are installed in the cavity. A fabricating method includes forming a package body having a cavity with a depth of 250 μm to 450 μm and at least one lead frame disposed at the bottom surface of the cavity, mounting at least one light emitting element on the lead frame, and molding a molding member in the cavity.