3D LED Emissive Display Bonding for Direct Color Emission
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Solution Overview
Problem
Existing processes for manufacturing color LED screens with three-dimensional semiconductor elements, such as nanofils or microfils, face challenges in achieving direct emission with diverse wavelengths without wavelength conversion elements, which complicates the manufacturing process and can lead to decreased electro-optical efficiency.
Innovation Solution
A process involving a control circuit with metal connection studs and an optoelectronic circuit with emission cells, where a first metal layer is applied to the control circuit and a second metal layer to the optoelectronic circuit, allowing direct bonding and trench formation to connect emission cells to distinct connection studs, along with a reflective layer and transparent conductive layer for efficient electromagnetic radiation emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wavelength conversion elements are used to produce polychromatic screens, then color diversity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes wavelength conversion elements from the system entirely. Instead of using phosphor layers or conversion materials on top of LEDs, the invention uses arrays of nanowire LEDs with different bandgaps that directly emit different wavelengths. This extraction of the conversion layer simplifies the device structure and manufacturing process while maintaining polychromatic capability.
Solution Approach 2:
The patent applies local quality by creating spatially varying nanowire structures with different compositions and bandgaps across the device. Each region contains nanowires tailored to emit specific wavelengths, allowing direct emission of multiple colors without conversion elements. This local differentiation enables color diversity while avoiding the complexity of wavelength conversion layers.
2Adaptability or versatility
If wavelength conversion elements are used, then polychromatic emission is achieved, but electro-optical conversion efficiency decreases
Solution Approach 1:
By removing wavelength conversion elements, the patent eliminates the energy losses associated with phosphor conversion. Each nanowire LED directly converts electrical energy to optical energy at its specific wavelength, avoiding the intermediate conversion step that inherently loses efficiency. The series connection architecture ensures each LED operates at optimal current density for maximum efficiency.
Solution Approach 2:
The patent changes the fundamental parameter of emission mechanism from indirect wavelength conversion to direct bandgap emission. By tuning the bandgap parameter of individual nanowires through composition control, the system achieves polychromatic emission while maintaining high electro-optical conversion efficiency at each wavelength.
3Reliability
If direct hybrid bonding is used to fix control circuit to optoelectronic circuit, then electrical connection is improved, but manufacturing difficulty increases due to surface preparation requirements
Solution Approach 1:
The patent performs preliminary action by pre-forming through-contact holes in the control circuit substrate before bonding. These holes provide ready-made pathways for electrical connections, eliminating the need for complex post-bonding alignment and reducing surface preparation requirements. The control circuit is prepared in advance with integrated through-holes that simplify the subsequent bonding process.
Solution Approach 2:
The patent introduces intermediary through-contact holes as mediators between the control circuit and optoelectronic circuit. These holes filled with conductive material serve as intermediate connection structures that facilitate reliable electrical bonding while reducing the complexity of direct surface-to-surface hybrid bonding. The intermediaries provide tolerance for alignment variations and simplify surface preparation.
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 process simplifies the manufacturing of direct-emission color LED screens with three-dimensional semiconductor elements, enhancing electro-optical efficiency and reducing complexity by eliminating the need for wavelength conversion elements and additional metallization layers.
Implementation Method 1
a reflective layer and transparent conductive layer for efficient electromagnetic radiation emission
Implementation Method 2
a reflective layer and transparent conductive layer for efficient electromagnetic radiation emission
Data Source
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AI summary
The present description relates to a process for manufacturing a three-dimensional LED-based emissive screen, comprising the following steps: a) depositing a first metal layer (207) on a face of a control circuit; b) depositing a second metal layer (117) on a face of an optoelectronic circuit; c) joining the optoelectronic circuit to the control circuit by direct bonding of the second metal layer (117) to the first metal layer (207), while aligning the optoelectronic circuit relative to the control circuit such that various emission cells (101R, 101G, 101B) of the optoelectronic circuit are arranged facing separate metal connection pads (203) of the control circuit; and d) forming, starting from the face of the optoelectronic circuit opposite the control circuit, trenches (211) that laterally bound each emission cell (101R, 101G, 101B).