Conductive Substrate Protrusions for Solid State Lighting
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Solution Overview
Problem
Conventional solid-state light emission devices face issues such as high manufacturing costs due to complex and time-consuming processes, thermal expansion mismatches leading to cracking and delamination, reduced light emission efficiency due to non-emitting areas and electrode blockages, and challenges with reflective layers melting during high-temperature deposition.
Innovation Solution
The use of a conductive substrate with protrusions and monolithic crystal structures for light emission layers, a reflective layer formed between the substrate and emission layers, and a transparent conductive layer to enhance light emission efficiency, along with electrode arrangements on opposite sides to prevent damage and allow effective cooling, eliminating the need for wire bonding and simplifying packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LED structures are used with flat substrates, then manufacturing processes are established, but thermal expansion mismatch causes cracking and delamination
Solution Approach 1:
The patent applies curvature by forming protrusions with curved surfaces on the substrate instead of using flat surfaces. The light emission layers are formed on these curved protrusions, which helps accommodate thermal expansion differences and prevents cracking and delamination during operation.
Solution Approach 2:
The patent implements local quality by creating protrusions with specific curved geometries in certain regions of the substrate. The light emission layers are selectively formed on these protrusions rather than uniformly across the entire substrate, allowing different regions to have different functional properties and stress distributions.
2Ease of manufacture
If selective etching is used to form electrodes on light emission layers, then electrode formation is achieved, but manufacturing complexity and time increase
Solution Approach 1:
The patent extracts the light emission layers from flat substrate surfaces and relocates them to protrusions. This geometric separation allows electrodes to be formed on the substrate surface without requiring selective etching of the light emission layers, as the layers are naturally positioned away from the electrode formation areas.
Solution Approach 2:
Instead of forming electrodes by removing material (etching) from the light emission layers, the patent inverts the approach by forming protrusions first and then depositing light emission layers on them. This allows electrodes to be formed by simple deposition on the substrate surface without complex etching steps.
3Ease of manufacture
If non-emitting areas are created for electrode placement, then electrode formation is enabled, but active light emission area and efficiency are reduced
Solution Approach 1:
The patent transitions from a two-dimensional flat substrate to a three-dimensional structure with protrusions. This dimensional change allows electrodes to be placed on the substrate surface in regions that do not compromise the light emission area on the protrusions, effectively separating electrode placement and light emission functions in different spatial dimensions.
Solution Approach 2:
By forming light emission layers on curved protrusions, the patent maximizes the light emission surface area relative to the substrate footprint. The curved surfaces of the protrusions provide extensive emission areas while maintaining compact device dimensions, allowing electrodes to be placed on the substrate without creating large non-emitting areas.
4Illumination intensity
If metallic reflective layers are deposited at high temperatures, then light reflection is achieved, but the reflective layer melts and loses reflectivity
Solution Approach 1:
The patent changes the deposition temperature parameter from high temperature to low temperature processes. By forming light emission layers and reflective structures at lower temperatures, the reflective layer materials can maintain their structural integrity and reflectivity without melting or degrading during the deposition process.
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
This approach significantly improves active light emission areas and efficiency, prevents cracking and delamination, effectively directs light emission, and reduces packaging complexity and costs, resulting in more reliable and efficient solid-state lighting devices.
Implementation Method 1
effective cooling can be provided by an entire conductive substrate during the lighting operation
Implementation Method 2
a reflective layer can be properly formed under the light emission layers to effectively reflect the emitted light to intended light illumination directions
Implementation Method 3
light emission layers disposed over the first protrusion surface, wherein the light emission layers can emit light when an electric field is applied across the light emission layers
Data Source
AI summary
A light emitting device includes a conductive substrate having a first substrate surface and comprising a conductive material, a protrusion formed on the conductive substrate, wherein the protrusion is defined in part by a first protrusion surface that is not parallel to the first substrate surface, and light emission layers disposed over the first protrusion surface. The light emission layers can emit light when an electric field is applied across the light emission layers.