Hybrid Microdisplay With Replaceable Micro-LED Dies
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Solution Overview
Problem
Monolithically formed micro LED arrays face challenges in achieving high yields due to defective devices, which are difficult to repair and require additional space for redundancy, affecting the provision of closely packed, small pixels.
Innovation Solution
A method involving bonding a backplane to a monolithic LED structure with reversible contacts, allowing for the removal and replacement of defective LED dies by breaking and reforming these bonds, and forming physically isolated LED dies to ensure high yield without needing redundancy space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If monolithic growth is used to form micro LED arrays with ultra-fine pitch, then manufacturing efficiency and resolution are improved, but the ability to repair defective devices is worsened due to the integrated structure
Solution Approach 1:
The monolithic LED array is segmented into individual replaceable dies while maintaining the integrated growth structure. Each die can be independently removed and replaced without affecting other pixels, resolving the contradiction between maintaining ultra-fine pitch integration and enabling repair of defective devices.
2Reliability
If redundancy schemes are implemented to mitigate defective pixels, then display reliability is improved, but device area is worsened due to additional space requirements
Solution Approach 1:
Instead of allocating permanent redundant pixels, the invention implements a replaceable die architecture where defective pixels can be removed and replaced. This eliminates the need for permanent redundancy space while maintaining high display yield through repair capability.
3Manufacturing precision
If closely packed small LED devices are provided to achieve high resolution, then manufacturing precision is improved, but ease of repair is worsened due to space constraints
Solution Approach 1:
The closely packed LED array is divided into independently replaceable dies. Each die maintains the ultra-fine pitch positioning for high resolution, while the modular segmentation enables individual access and replacement of defective devices without disrupting the overall high-density arrangement.
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
Enables high-resolution displays with functional LED dies by allowing individual replacement and identification of defective devices, maintaining electrical conductivity and enhancing light extraction.
Implementation Method 1
bonding comprises forming a reversible bond between at least one of the plurality of backplane electrical contacts and a corresponding electrical contact of the monolithic light emitting diode structure
Implementation Method 2
using techniques like metal-to-metal bonding and eutectic bonding for electrical conductivity and light extraction
Implementation Method 3
monolithic light emitting diode structure comprising a corresponding plurality of electrical contacts
Implementation Method 4
Light emitting diode (LED) devices are known to provide highly efficient and controllable light sources for display applications
Implementation Method 5
providing a reflective surface to aid light extraction from individual LED devices
Data Source
AI summary
A method of forming a display comprising: bonding a backplane comprising a plurality of backplane electrical contacts to a monolithic light emitting diode structure comprising a corresponding plurality of electrical contacts, wherein bonding comprises forming a reversible bond between at least one of the plurality of backplane electrical contacts and a corresponding electrical contact of the monolithic light emitting diode structure; and removing material from the monolithic light emitting diode structure to provide a plurality of physically isolated light emitting diode dies, thereby to enable removal and/or replacement of at least one physically isolated light emitting diode die by reversing the reversible bond between the at least one of the plurality of backplane electrical contacts and the corresponding electrical contact of the monolithic light emitting diode structure.