Reflective Planar Dielectric Layer for Light Emitting Device Submount
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting devices suffer from inefficiencies due to internal light reflection and absorption by the substrate, leading to reduced luminance output, particularly in die on ceramic (DoC) LED packaging where reflector cups are not economically viable.
Innovation Solution
A submount with a metallization layer and a reflective planar dielectric layer that fills regions between circuit traces, minimizing light absorption and reflecting internally reflected light back towards the desired output, while allowing for efficient electrical coupling and manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a reflective layer is placed upon the substrate and adjacent the stack, then internally reflected light is reflected back up to the lens element, but at least a portion of the light is likely to be absorbed by either the elements of the stack or the substrate
Solution Approach 1:
The patent extracts the reflective function from the substrate itself and places it on a separate layer (reflective layer 140) positioned between the substrate and the light stack. This separation allows the substrate to maintain its structural and electrical functions while the dedicated reflective layer handles light reflection, reducing light absorption losses without complicating substrate manufacturing.
Solution Approach 2:
The patent employs a composite structure combining the substrate material with a reflective layer material. This composite approach allows optimization of each layer for its specific function: the substrate provides mechanical support and electrical connectivity, while the reflective layer provides optimized light reflection properties, thereby reducing overall light loss without compromising manufacturing ease.
2Illumination intensity
If the substrate is made transparent or semi-transparent to allow light passage, then light can escape through the substrate, but most substrates are not transparent and therefore some light is lost/absorbed with each transit through the substrate
Solution Approach 1:
The patent converts the normally harmful effect of light absorption by the substrate into a beneficial reflection process. By placing a reflective layer between the substrate and the light stack, light that would have been absorbed by the substrate is instead reflected back through the optical element, transforming energy loss into useful light output.
Solution Approach 2:
The patent addresses the light absorption problem by adding a new dimensional element (the reflective layer) between the substrate and the light stack. This intermediate layer creates an additional optical path dimension, allowing light to be reflected back through the optical element rather than being absorbed by the substrate, thereby increasing light output without requiring substrate transparency.
3Loss of energy
If a reflective cavity is formed for mounting stacks, then light reflection is improved, but the stack cannot be mounted on the substrate
Solution Approach 1:
The patent segments the light reflection function from the mounting structure. The reflective layer is positioned adjacent to the light stack but separate from the substrate mounting surface, allowing the stack to be mounted on the substrate while the reflective layer independently provides light reflection. This segmentation enables both mounting capability and improved light reflection efficiency.
Solution Approach 2:
The patent introduces an intermediary reflective layer that mediates between the substrate-mounted stack and the optical element. This intermediary layer provides the reflective function without interfering with the mounting connection between the stack and substrate, thereby maintaining ease of operation while improving light reflection efficiency.
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 enhances luminance output by up to 5% by preventing light loss through the substrate and improving reflectivity, making the technology more economically viable and efficient.
Implementation Method 1
a reflective planar dielectric layer that fills regions between the circuit traces... reflects the internally reflected light back toward the desired light output element
Data Source
AI summary
A submount for a light emitting stack includes a substrate and a metallization layer having circuit traces and a planar dielectric layer that fills regions between the circuit traces. The planar dielectric layer serves to minimize the amount of light lost/absorbed by the substrate and preferably reflects the internally reflected light back toward the desired light output element. To facilitate efficient manufacture, a dielectric paste is applied over the metalized layer, then planed to expose at least portions of the metal conductors for the subsequent coupling to the light emitting stack. Pedestal elements are preferably provided at select locations on the circuit traces to facilitate this coupling while allowing the remainder of the circuit traces to be covered with the dielectric layer.