LED Inspection Using Voltage-Sensing Film for Parallel Testing
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Solution Overview
Problem
The challenge of inspecting small light-emitting diodes (LEDs) with reduced size poses issues in ensuring high yield and uniform quality, as traditional inspection methods are time-consuming and require precise alignment of probes with tiny electrodes, leading to probe wear and increased costs.
Innovation Solution
An inspection system utilizing an excitation light source, voltage-sensing film, and image capture device to generate open-circuit voltages, display changes, and sensing images for rapid inspection, employing a voltage-sensing medium layer and electrode layers to enhance voltage sensing and provide gain effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional contact-based inspection methods are used with small probes, then measurement precision can be achieved, but the inspection process becomes time-consuming and probes wear out quickly
Solution Approach 1:
The patent replaces the mechanical contact-based probe inspection system with a non-contact optical inspection system. The voltage-sensing film with liquid crystal medium detects electrical characteristics through optical changes instead of physical contact, eliminating probe wear and enabling parallel inspection of multiple LEDs simultaneously, thus dramatically improving inspection speed while maintaining measurement precision.
Solution Approach 2:
The patent creates an optical copy of the electrical characteristics by converting voltage information into visual display changes on the voltage-sensing film. The liquid crystal medium translates electrical voltage into optical patterns that can be captured by imaging devices, allowing rapid non-contact measurement without physical probe contact.
2Manufacturing precision
If probe size is reduced to match tiny LED electrodes, then alignment precision improves, but manufacturing difficulty and probe wear increase
Solution Approach 1:
The patent eliminates the need for precision-matched physical probes by replacing the mechanical measurement system with an optical sensing system. The voltage-sensing film covers a large area and can detect electrical characteristics of multiple LEDs simultaneously without requiring alignment with individual tiny electrodes, greatly simplifying manufacturing while maintaining measurement precision.
Solution Approach 2:
The patent transitions from one-dimensional point-to-point probe contact to a two-dimensional planar sensing approach. The voltage-sensing film provides a large-area sensing surface that can detect electrical characteristics across multiple LEDs simultaneously, eliminating the need for precise point alignment with tiny electrodes.
3Measurement precision
If contact-based inspection of multiple LEDs is performed sequentially, then measurement accuracy is maintained, but inspection time increases significantly
Solution Approach 1:
The patent merges multiple individual inspection operations into a single parallel inspection process. The voltage-sensing film with its large sensing area can detect electrical characteristics of multiple LEDs simultaneously through optical changes, converting sequential measurements into parallel operations and dramatically reducing inspection time while maintaining measurement accuracy.
Solution Approach 2:
The patent enables continuous simultaneous inspection of multiple LEDs rather than sequential measurement. The optical sensing system continuously captures voltage information from all LEDs in the array at once, eliminating idle time between measurements and maintaining continuous useful action throughout the inspection process.
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 rapid and comprehensive inspection of a large number of LEDs by detecting open-circuit voltages through non-contact methods, allowing for quick classification of good and bad LEDs based on electrical characteristics.
Implementation Method 1
The voltage-sensing film is configured to generate a display change according to a driving voltage. The voltage-sensing film includes a voltage-sensing medium layer and a first electrode layer.
Implementation Method 2
The first electrode layer is disposed in the voltage-sensing medium layer to provide a gain effect of the plurality of open-circuit voltages
Implementation Method 3
The excitation light source is adapted to provide an excitation beam to the plurality of light-emitting diodes so that the plurality of light-emitting diodes generate a plurality of open-circuit voltages
Implementation Method 4
The illumination light source provides an illumination beam to the voltage-sensing film to generate a sensing image according to the display change
Data Source
AI summary
An inspection system includes an excitation light source, a voltage-sensing film, an illumination light source, an image capture device. The excitation light source provides an excitation beam to light-emitting diodes to generate open-circuit voltages. The voltage-sensing film is at a top side of the light-emitting diodes and includes a voltage-sensing medium layer and a first electrode layer. The first electrode layer is in the voltage-sensing medium layer to provide a gain effect of the open-circuit voltages, so that the voltage-sensing medium layer senses the open-circuit voltages, and a display of the voltage-sensing medium layer is changed with a portion or all of the open-circuit voltages. The illumination light source provides an illumination beam to the voltage-sensing film to generate a sensing image according to a display change. The image capture device is on a transmission path of the sensing image and receives the sensing image to generate an inspection result.