UV LED Package With Sapphire Window for Light Extraction
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Solution Overview
Problem
Light emitting packages with quartz lenses have low reliability due to their low strength and susceptibility to external impact, and they also suffer from low light extraction efficiency.
Innovation Solution
A light emitting package design featuring a ceramic body with a cavity housing a UV light emitting diode chip, covered by a light transmission member with a sapphire layer and a light loss prevention layer, such as magnesium fluoride, to enhance reliability and light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a quartz lens is used in the light emitting package, then light transmittance is improved, but reliability deteriorates due to low strength and susceptibility to external impact
Solution Approach 1:
The patent changes the material parameter of the lens from quartz to sapphire. Sapphire has both high light transmittance in the UV range and high mechanical strength, thereby simultaneously improving light transmittance and reliability without the fragility issues of quartz
Solution Approach 2:
The patent employs a composite structure consisting of a sapphire lens layer and a light extraction enhancement layer. This composite material approach allows the sapphire to provide mechanical strength and UV transmittance while the enhancement layer optimizes light extraction efficiency, together resolving the contradiction between transmittance and reliability
2Illumination intensity
If a quartz lens is used in the light emitting package, then light transmittance is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The patent changes the lens material from quartz to sapphire, which has different optical properties including higher refractive index. This parameter change in material composition enables better light extraction efficiency while maintaining high UV transmittance
Solution Approach 2:
The composite structure of sapphire lens plus light extraction enhancement layer works synergistically to maximize both light transmittance and light extraction efficiency, overcoming the limitations of using quartz alone
3Device complexity
If the light emitting diode chip is mounted close to the lens, then device complexity is reduced, but light extraction efficiency deteriorates due to insufficient space for optimal light path
Solution Approach 1:
The patent introduces a vertical spacing dimension between the LED chip and lens, creating an air gap that allows optimized light extraction paths. This dimensional adjustment enables efficient light extraction without significantly increasing overall device complexity
Solution Approach 2:
The air gap or spacer acts as an intermediary element between the LED chip and sapphire lens. This intermediary space optimizes the light extraction efficiency by allowing proper light propagation paths while the overall structure remains relatively simple
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 use of a sapphire light transmission layer and a light loss prevention layer improves the package's resistance to external impact and enhances light extraction efficiency, achieving higher reliability and luminous efficacy.
Implementation Method 1
A light emitting diode is an inorganic semiconductor device that emits light generated through recombination of electrons and holes
Implementation Method 2
emits light generated through recombination of electrons and holes
Implementation Method 3
UV light emitted from the light emitting diode chip may sequentially pass through an air layer, the lower light loss prevention layer, and a sapphire layer so as to be emitted from the light emitting package
Implementation Method 4
a light loss prevention layer formed on at least one surface of the light transmission layer
Data Source
AI summary
The present invention relates to a light emitting package. A light emitting package according to an embodiment of the present invention may include a body, a light emitting diode chip, and a light transmission member. The body includes a cavity open at an tipper side thereof and may be formed of a ceramic material. The light emitting diode chip is mounted in the cavity of the body and may generate and emit UV light. The light transmission member may be disposed on top of the body to cover the cavity. In addition, the light transmission member may include a light transmission layer formed of sapphire and a light loss prevention layer formed on at least one surface of the light transmission layer. The light loss prevention layer may include a lower light loss prevention layer formed on a lower surface of the light transmission layer. The light emitting diode chip and the light transmission member may be spaced apart from each other to form a space therebetween. UV light emitted from the light emitting diode chip may sequentially pass through an air layer, the lower light loss prevention layer, and a sapphire layer so as to be emitted from the light emitting package.