RF-Induced Micro LED Inspection for Contactless Defect Detection
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Solution Overview
Problem
Existing micro LED inspection processes are challenging due to the small size of micro LEDs, making contactless testing with high detection efficiency difficult, as conventional testing methods can damage the chips and have limitations in defect detection.
Innovation Solution
A system comprising a glass panel with a conductive layer on top of an LED, a radio frequency generator to apply a radio frequency signal for contactless illumination, a camera to capture images of the illuminated LEDs, and a processor to determine LED functionality based on illumination intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EL tests are used to identify more defects, then detection efficiency is improved, but chip damage occurs due to contacting the LED chips
Solution Approach 1:
A conductive layer is introduced as an intermediary between the RF signal source and the LED chip. The conductive layer converts RF signals to electrical signals that activate the LED without direct contact, enabling non-contact testing while maintaining EL test effectiveness for defect detection
Solution Approach 2:
The patent replaces mechanical contact-based electrical connection with electromagnetic field-based RF signal transmission. The RF signal wirelessly induces electrical signals in the conductive layer, eliminating the need for physical contact probes that could damage the micro LED chips
2Object-affected harmful factors
If PL tests are used for contactless testing, then chip damage is avoided, but detection efficiency is reduced
Solution Approach 1:
The patent replaces optical-based PL testing with electromagnetic-based RF signal transmission. The RF signals induce electrical signals in the conductive layer that directly activate the LED, providing more sensitive defect detection while maintaining contactless operation
Solution Approach 2:
The patent changes the testing parameter from optical excitation (PL) to electromagnetic induction (RF). This parameter change enables the system to achieve both contactless operation and high detection efficiency by utilizing the LED's electroluminescence property through induced electrical signals
3Measurement precision
If conventional testing equipment is used for micro LED inspection, then testing can be performed, but the process is slow and difficult due to small chip size
Solution Approach 1:
The conductive layer serves multiple functions: it acts as an RF signal receiver, an electrical signal generator, and an LED activator. This multi-functionality enables a single system to perform both contactless signal transmission and efficient LED activation, improving testing speed for micro LEDs
Solution Approach 2:
The conductive layer as an intermediary enables wireless communication between the RF signal source and the LED chip. This intermediary system allows for rapid signal transmission and activation without the slow, manual positioning required by conventional contact-based testing equipment
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 solution enables efficient, contactless inspection of micro LEDs with high detection efficiency, reducing the risk of chip damage and improving the accuracy of defect identification, thereby streamlining the micro LED manufacturing process.
Implementation Method 1
a radio frequency signal applied to a glass panel may illuminate the LED by induction through the conductive layer
Data Source
AI summary
The system includes a glass panel, a radio frequency generator, a camera, and a processor. The glass panel includes a conductive layer, and the conductive layer is disposed on top of an LED. The radio frequency generator is configured to apply a radio frequency signal to the glass panel, and the radio frequency signal illuminates the LED by induction through the conductive layer. The camera is configured to capture an image of the LED illuminated by the radio frequency signal. The processor is in electronic communication with the camera and is configured to receive the image from the camera and determine whether the LED is a defective LED or a functioning LED based on the image of the LED.