Micro-LED Display Transfer With Non-Contact Defect Screening
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Solution Overview
Problem
Existing display devices face challenges in reducing material consumption, non-transfer percentage of light-emitting elements, and improving transfer process speed and product yield, particularly in transferring light-emitting elements to panel substrates.
Innovation Solution
A display device design that inspects the light-emitting state of elements in a non-contact manner during transfer, transferring only non-defective main elements and redundant elements when necessary, using a black matrix to cover defective elements and an optical insulating layer to ensure accurate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all light-emitting elements are transferred to the panel substrate, then the display device can ensure sufficient light emission, but material consumption increases
Solution Approach 1:
The patent applies preliminary action by inspecting the light-emitting state of each light-emitting element before the transfer process. This allows defective elements to be identified in advance, enabling selective transfer of only non-defective elements to the panel substrate, thereby reducing material consumption while ensuring display reliability
Solution Approach 2:
The patent extracts defective light-emitting elements from the transfer process by identifying them through pre-transfer inspection. Only non-defective elements are transferred to the panel substrate, effectively removing defective elements from the manufacturing flow and reducing material waste
2Measurement precision
If inspection is performed during transfer process, then defective elements can be identified, but transfer process speed decreases
Solution Approach 1:
The inspection process is performed as a preliminary action before the actual transfer process. By completing defect detection in advance, the subsequent transfer process can proceed efficiently without interruption, maintaining high transfer speed while ensuring accurate defect identification
Solution Approach 2:
The patent replaces contact-based inspection methods with non-contact optical inspection. This substitution eliminates mechanical interference during the transfer process, allowing simultaneous or sequential inspection and transfer operations that maintain high productivity while achieving precise defect detection
3Reliability
If redundant light-emitting elements are transferred, then backup is provided for defective elements, but material consumption increases
Solution Approach 1:
By inspecting light-emitting elements before transfer, the system can identify non-defective elements in advance. This allows selective transfer of only the necessary number of good elements (one per pixel), eliminating the need to transfer redundant elements as backup, thereby reducing material consumption while maintaining display reliability
Solution Approach 2:
The inspection system enables the transfer process to self-select which elements to transfer based on their quality status. Only elements that pass the inspection criteria are transferred, creating a self-regulating system that optimizes material usage without requiring excessive redundancy
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 material consumption, manufacturing costs, defects, and power consumption while improving transfer process speed and product quality, leading to a more reliable and long-lasting display device.
Implementation Method 1
a black matrix having a plurality of openings defined therein respectively at positions corresponding to the plurality of light-emitting elements, wherein the black matrix is disposed on the plurality of light-emitting elements such that the plurality of light-emitting elements are exposed through the plurality of openings, respectively
Data Source
AI summary
A display device includes a micro light-emitting element. In an example, the display device includes a substrate including a display area and a non-display area, a driving chip disposed on the substrate in the display area, light-emitting elements electrically connected to the driving chip where the light-emitting elements and the driving chip are disposed in different layers in the display area, a pad electrode disposed in the non-display area of the substrate and electrically connected to the light-emitting elements, and a black matrix having a plurality of openings. An electric field is applied to each of the light-emitting elements in a non-contact manner to determine whether a current therefrom is detected through the pad electrode. Then the opening corresponding to the light-emitting element from which no current is detected through the pad electrode can be filled with the black matrix.