3D Phosphor-in-Glass LED Cover for Low-Reflection Light Extraction
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Solution Overview
Problem
Conventional LED packages with flat phosphor in glass cover structures suffer from reduced light emission efficiency and impaired color over angle emission due to internal reflection and the need for additional adhesive layers, which absorb light and reduce transmission efficiency.
Innovation Solution
A 3D shaped phosphor in glass cover structure is used, forming a hemispherical dome over the LED chip to reduce internal reflection and serve as a remote phosphor lumiphore, improving light emission efficiency and color uniformity, fabricated through lamination, sintering, and machining processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat phosphor in glass cover structure is used, then the LED chip is protected and light emission is provided, but internal reflection occurs and color uniformity deteriorates due to high angle light entry
Solution Approach 1:
The patent applies a curved (spheroidal) phosphor-in-glass cover structure instead of a flat planar structure. This curvature changes the angle at which light enters the phosphor layer, reducing internal reflection and improving light extraction efficiency while maintaining chip protection functionality.
Solution Approach 2:
The invention transitions from a two-dimensional flat phosphor layer to a three-dimensional curved phosphor-in-glass structure. This dimensional change allows light to enter at more favorable angles throughout the structure, reducing internal reflection and improving overall light emission efficiency.
2Reliability
If a flat phosphor in glass cover structure is used, then the LED chip is protected, but color uniformity deteriorates due to high angle light entry
Solution Approach 1:
The curved spheroidal structure ensures that light enters the phosphor layer at more consistent and favorable angles across the entire emission area, improving color uniformity while maintaining the protective function of the cover structure.
3Strength
If an additional adhesive layer is added to bond the phosphor in glass cover structure, then the structure is secured, but light transmission efficiency is reduced due to light absorption
Solution Approach 1:
The patent merges the bonding function into the phosphor-in-glass structure itself, eliminating the need for a separate adhesive layer. The glass structure provides both mechanical bonding strength and optimal light transmission by removing the light-absorbing adhesive interface.
Solution Approach 2:
The invention extracts and removes the adhesive layer from the structure, eliminating the source of light absorption. The bonding function is achieved directly through the phosphor-in-glass structure's design and material properties.
4Illumination intensity
If a 3D shaped phosphor in glass cover structure is used, then light emission efficiency and color uniformity are improved, but manufacturing complexity increases
Solution Approach 1:
The spheroidal shape provides optical benefits through its geometric properties, and this curvature can be achieved through established glass forming and shaping techniques, balancing performance improvement with manufacturing feasibility.
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 3D shaped phosphor in glass cover structure enhances light emission efficiency and color uniformity by reducing internal reflection and eliminating the need for an additional adhesive layer, resulting in improved light transmission and thermal insulation.
Implementation Method 1
The phosphor can be embedded in a glass cover structure that is bonded to the LED chip or device and can both protect the LED chip/device while also providing an emitted light in a desired frequency band
Implementation Method 2
The phosphor in glass cover structure can form a hemispherical dome over an LED chip, so that light incident on the inside surface of the dome will be at a more acute angle which can reduce the internal reflection of light emitted by the LED chip
Data Source
AI summary
The present disclosure relates to techniques for providing and fabricating a 3D shaped cover structure for a light emitting diode (LED) package that has improved light emission efficiencies and color over angle emissions over flat cover structures. The cover structure can form a hemispherical dome over an LED chip, so that light incident on the inside surface of the dome will be at a more acute angle which can reduce the internal reflection of light emitted by the LED chip. The cover structure can also serve as a remote phosphor lumiphore, thereby improving color over angle emission and reduce the need for an additional adhesion interface on the LED. The cover structure can be shaped during a green sheet lamination and sintering process to create the 3D shape. In other embodiments, a structure can be machined into a desired shape.