LED Package Barrier Wall for Glare Reduction
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Solution Overview
Problem
Existing LED packages struggle to achieve sufficient contrast between turned-on and turned-off regions, leading to glare issues in applications like vehicle headlamps, where light emission from one package can affect the irradiation region of another.
Innovation Solution
An LED package design featuring a barrier wall made of the same material as the package body, positioned parallel to the LED chip with its upper surface 50 μm or less from the phosphor sheet, and an encapsulation portion of a different material, which enhances light reflection and limits irradiation angles to improve contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional LED package structure is used, then the device complexity is low, but the contrast between turned-on and turned-off regions is insufficient
Solution Approach 1:
The package body is segmented into multiple functional regions including a first region for LED chip mounting and a second region for light emission control. A barrier wall divides these regions, creating distinct zones that control light propagation paths and improve contrast between active and inactive packages
Solution Approach 2:
An encapsulation portion filled with encapsulant material is introduced as an intermediary element between the LED chip and the external environment. This encapsulation portion, combined with the barrier wall, mediates light propagation by reflecting stray light and limiting emission angles, thereby enhancing contrast without requiring complex external optical components
2Illumination intensity
If light emission is increased for high output, then the illumination intensity improves, but glare affecting adjacent regions increases
Solution Approach 1:
The barrier wall is positioned at a specific height (50-150 μm from the phosphor sheet upper surface) to create localized light reflection zones. This local structural modification selectively controls light propagation in specific directions while maintaining high overall light output, preventing glare in adjacent regions without reducing total illumination intensity
Solution Approach 2:
The encapsulation portion is configured with specific dimensions (length and width both 50-200 μm) to control light emission in multiple spatial dimensions. By adjusting the encapsulation portion's dimensional parameters, the light emission is constrained to desired angular ranges, effectively managing glare while preserving high output in the intended illumination direction
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 significantly increases contrast by preventing light from a turned-on package from irradiating the region of a turned-off package, effectively reducing glare and enhancing the effectiveness of glare prevention in vehicle headlamps.
Implementation Method 1
An LED package having improved contrast... an upper surface of the barrier wall being higher than an upper surface of the LED chip with respect to the lower surface of the concave portion and disposed at a level that is 50 μm or less from an upper surface of the phosphor sheet
Implementation Method 2
an encapsulation portion disposed on the LED chip, a side surface of the phosphor sheet and a side surface of the barrier wall, the encapsulation portion being formed of a material different from the common material
Implementation Method 3
a phosphor sheet disposed on the LED chip... an upper surface of the barrier wall being higher than an upper surface of the LED chip with respect to the lower surface of the concave portion and disposed at a level that is 50 μm or less from an upper surface of the phosphor sheet
Data Source
AI summary
A light emitting diode (LED) package is provided. The LED package includes a package body having a concave portion; an LED chip disposed on the concave portion; a phosphor sheet disposed on the LED chip; a barrier wall disposed on the concave portion and spaced apart from the LED chip by a first distance, the barrier wall being disposed in parallel with at least one side surface of the LED chip, an upper surface of the barrier wall being higher than an upper surface of the LED chip with respect to the lower surface of the concave portion and disposed at a level that is 50 μm or less from an upper surface of the phosphor sheet; and an encapsulation portion disposed on the LED chip, a side surface of the phosphor sheet and a side surface of the barrier wall.