Polychrome Wafer Structure With Shared ASIC Color Driving
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Solution Overview
Problem
Existing micro-LED display technologies face challenges in achieving high brightness, high resolution, and small screen size due to limitations in wavelength conversion methods, which result in unconverted light leakage and spectral inconsistencies, and require complex and costly driving systems for multiple color emissions.
Innovation Solution
A polychrome wafer structure is developed, where multiple epitaxial dies emitting different colors are bonded to a common monolithic integrated circuit, allowing a single ASIC to drive multiple light-emitting devices, minimizing electrical driving systems and power consumption, and utilizing color converters like filters or quantum dots to achieve desired colors, while enabling simultaneous fabrication steps and high-density pixel arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wavelength conversion coating is applied to each light emitting device, then color conversion is achieved, but coating dependency and light leakage occur affecting spectral consistency
Solution Approach 1:
The patent introduces a transfer wafer as an intermediary substrate to temporarily hold multiple epitaxial dies during the bonding process. This mediator enables precise alignment and simultaneous bonding of multiple dies to a single ASIC, eliminating the need for individual coating applications that cause spectral inconsistency. The transfer wafer acts as a buffer that facilitates the intermediary step of organizing dies before final attachment.
2Ease of operation
If multiple dedicated driving circuits are used for each color emission, then precise control of each light emitting device is achieved, but device complexity and power consumption increase
Solution Approach 1:
The patent merges multiple light-emitting devices of different colors onto a single ASIC substrate. By bonding multiple epitaxial dies (emitting different colors) to one common ASIC, the system combines what would traditionally require separate driving circuits into a unified integration. This merging reduces the overall number of driving circuits needed while maintaining precise control through the shared ASIC architecture.
Solution Approach 2:
The single ASIC serves multiple functions by controlling light-emitting devices of different colors simultaneously. The universal ASIC replaces what would traditionally require dedicated specialized driving circuits for each color, achieving multi-functionality where one component performs the role of multiple separate drivers, thereby reducing system complexity.
3Volume of moving object
If multiple epitaxial dies are bonded to a common ASIC, then form factor is minimized and power consumption is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by first bonding multiple epitaxial dies to a transfer wafer before final attachment to the ASIC. This preliminary arrangement on the transfer wafer allows for pre-alignment and organization of dies in the desired configuration. By performing this preparatory bonding step first, the system facilitates subsequent precise alignment with the ASIC, making the high-precision bonding more manageable through staged fabrication.
4Measurement precision
If high-resolution pixel arrays with pixel size lower than 10 microns are implemented, then display resolution is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent segments the display into multiple epitaxial dies, each containing pixel arrays. By dividing the overall display structure into separate die segments that can be manufactured independently and then bonded together, the system achieves high resolution through the cumulative effect of multiple segments. This segmentation allows each die to be optimized for high-density pixelation while maintaining manufacturability through modular fabrication and assembly.
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 reduces power consumption, minimizes form factor, and enhances color rendering and resolution by allowing a single driving circuit to manage multiple colors, achieving efficient and uniform color output with reduced production complexity and cost.
Implementation Method 1
a plurality of structured first epitaxial dies having first light-emitting devices configured to emit light of a first color and at least a plurality of structured second epitaxial dies having second light-emitting devices configured to emit light of a second color
Implementation Method 2
utilizing color converters like filters or quantum dots to achieve desired colors
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 2E~3C
AI summary
A polychrome wafer structure (100,200,200") comprising a plurality of structured first epitaxial dies (102) having first light-emitting devices (107) configured to emit light of a first color, at least a plurality of structured second epitaxial dies (103) having second light-emitting devices (107') configured to emit light of a second color. The plurality of the structured first epitaxial dies (102) and the plurality of the structured second epitaxial dies (103) are bonded on a target wafer (507) with a plurality of common monolithic integrated circuits in a manner that the at least one first die and the at least one second die is connected to one common monolithic integrated circuit (101) for simultaneously driving at least one first epitxial die (102) having light-emitting device (107) and at least one second epitaxial die (103) having light-emitting device (107') by the respective one common monolithic integrated circuit (101).