UV LED Package Structure for Plane Light Source Generation
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Solution Overview
Problem
Current LED package structures primarily produce point light sources, leading to total reflection issues due to material refractive indexes and excessive energy concentration of UV light, which is challenging for designing plane light sources and can result in uncontrollable illumination during light curing.
Innovation Solution
An LED package structure with a ceramic substrate, aluminum layer, UV LED chip, glass glue layer, light-guiding layer, and metal reflective layer is designed to guide and reflect UV light laterally, creating a plane light source by distributing energy uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional LED package structures are used, then point light sources are produced, but total reflection occurs and UV energy becomes excessively concentrated
Solution Approach 1:
The patent transforms the light emission from a point source (0D) to a plane source (2D) by introducing a light-guiding layer with specific refractive index and a reflective layer. This dimensional change distributes the UV energy across a larger area, reducing energy concentration while maintaining illumination intensity. The light-guiding layer redirects light rays that would otherwise concentrate at a point to emit uniformly across a planar surface.
Solution Approach 2:
The light-guiding layer acts as an intermediary between the UV LED chip and the external environment. With a refractive index between 1.3 and 1.7, it mediates the light propagation by reducing total internal reflection and guiding light rays to the reflective layer, which then distributes them uniformly across the package structure's lateral sides, preventing excessive energy concentration.
2Device complexity
If point light sources are used, then UV LED structure is simple, but extra optical components are required to diffuse UV light
Solution Approach 1:
The patent merges the light-guiding function and the structural support function into a single light-guiding layer integrated with the package substrate. This layer combines optical properties (refractive index between 1.3-1.7) with mechanical support, eliminating the need for separate optical diffusing components and simplifying the overall device structure while maintaining ease of manufacture.
Solution Approach 2:
The light-guiding layer serves multiple functions simultaneously: it acts as a structural support element, an optical waveguide to redirect light rays, and a medium to reduce total internal reflection. This multi-functionality eliminates the need for separate optical components, reducing device complexity while maintaining manufacturing simplicity.
3Illumination intensity
If plane light source is designed, then UV energy is distributed uniformly, but light guidance and reflection mechanisms are required
Solution Approach 1:
The patent achieves uniform UV distribution by carefully selecting and controlling the refractive index parameter of the light-guiding layer (between 1.3 and 1.7). This parameter change optimizes light propagation characteristics, enabling the layer to guide light rays effectively to the reflective layer without requiring complex optical mechanisms, thus achieving uniform illumination with minimal structural complexity.
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 effectively transforms UV LEDs into plane light sources, preventing excessive energy concentration and ensuring uniform illumination, enhancing the safety and efficiency of UV light applications.
Implementation Method 1
the light-guiding layer covers the UV LED chip... the front light emission of the UV LED is guided to the metal reflective layer via the light-guiding layer
Implementation Method 2
reflected from the metal reflective layer to the lateral sides of the package structure... exhibiting the light field of a plane light source
Data Source
AI summary
The present invention provides a light-emitting diode (LED) package structure and the method for manufacturing the same. First, a ceramic substrate is provided. Then, an ultraviolet (UV) LED chip, a light-guiding layer, and a metal reflective layer are disposed on the substrate sequentially. By means of the metal reflective layer, the emission light of the UV LED from the light-emitting side is reflected laterally and thus making the UV LED package structure output a plane light source.