μLED Electroluminescent Structure With 3D Cavities for Light Conversion
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Solution Overview
Problem
Current micro light-emitting diode (μLED) displays face limitations in light conversion efficiency due to the need for increased quantum dot concentration or encapsulating thickness in optical conversion materials, which raises manufacturing costs and hinders miniaturization and thinning of the displays.
Innovation Solution
The electroluminescent device incorporates a semiconductor layer with regularly arranged 3D structures that define cavities, allowing an optical conversion material to be filled within these cavities, thereby enhancing light absorption and conversion efficiency without increasing the overall thickness of the optical conversion material or the concentration of quantum dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the concentration of quantum dots in optical conversion materials is increased to improve light conversion efficiency, then the light conversion efficiency is improved, but the manufacturing cost increases
Solution Approach 1:
The patent transitions from a planar optical conversion layer to a three-dimensional cavity structure. The optical conversion material is positioned within cavities that extend into the semiconductor layer, creating vertical light-matter interaction paths. This dimensional change increases the effective interaction volume and light absorption probability without increasing the planar area or material concentration, thereby improving conversion efficiency while controlling manufacturing costs.
Solution Approach 2:
The semiconductor layer is designed with a porous or cavity-containing structure where optical conversion materials are positioned within these cavities. This porous architecture increases the surface area and light-trapping capability within a given volume, enhancing light conversion efficiency without requiring higher quantum dot concentrations, thus avoiding increased manufacturing costs.
2Loss of energy
If the encapsulating thickness of optical conversion materials is increased to improve light absorption efficiency, then the light absorption efficiency is improved, but the miniaturization of μLED dies is hindered
Solution Approach 1:
Instead of increasing the planar thickness of the optical conversion layer, the patent utilizes vertical cavities that extend into the semiconductor layer. This creates extended light interaction paths in the vertical dimension while maintaining a thin overall device profile, improving light absorption efficiency without increasing the μLED die volume.
Solution Approach 2:
The optical conversion material is nested within cavities formed in the semiconductor layer. This nesting arrangement allows the optical conversion function to be integrated within the existing device structure, maximizing light absorption within a compact volume and enabling miniaturization of the μLED dies.
3Loss of energy
If the encapsulating thickness of optical conversion materials is increased to improve light conversion efficiency, then the light conversion efficiency is improved, but the thinning of μLED display is limited
Solution Approach 1:
The patent employs vertical cavities that extend into the semiconductor layer to increase the light interaction path length without increasing the overall display thickness. By utilizing the vertical dimension within the existing device profile, the design achieves improved light conversion efficiency while maintaining a thin display form factor.
Solution Approach 2:
The cavity structure creates a porous architecture within the semiconductor layer, increasing the effective surface area and light-trapping capability. This allows enhanced light conversion efficiency within a thin device profile, as the porous structure provides extended interaction paths without adding to the overall thickness of the display.
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 improves light absorption/conversion efficiency, reduces manufacturing costs, and enables the miniaturization and thinning of electroluminescent devices and μLED displays.
Implementation Method 1
the monochromatic light emitted from the μLED dies passes through optical conversion materials, such as photoluminescence fluorescent materials (e.g., photoluminescence phosphor), Quantum Dots (QD) materials, luminescent dyes
Data Source
AI summary
An electroluminescent device, wherein the electroluminescent device includes a first-conductivity-type semiconductor layer, a second-conductivity-type semiconductor layer, an active layer, a first electrode, a second electrode, and an optical conversion material. The active layer is disposed between the first-conductivity-type semiconductor layer and the second-conductivity-type semiconductor layer and electrically connected with these two. The first-conductivity-type semiconductor layer has a light-emitting surface disposed on a side opposite to the active layer, and includes a plurality of 3D structures arranged regularly, extending from the light-emitting surface towards the active layer to jointly define at least one cavity having a depth greater than 70% a thickness of the first-conductivity-type semiconductor layer. The optical conversion material is filled in the cavity.