LED Test Apparatus with Correction Map for Interference
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Solution Overview
Problem
Existing methods for testing LEDs' optical characteristics, such as sequentially turning on LEDs and using image sensors, face challenges in accurately identifying defective LEDs due to interference from adjacent LEDs and high costs, especially when testing micro LEDs.
Innovation Solution
A test apparatus that collectively irradiates multiple LEDs with light and measures photoelectric signals using probes, generating a correction map to account for light intensity variations across the irradiation region, allowing for simultaneous measurement and accurate identification of defective LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LEDs are tested sequentially one by one using image sensors, then measurement precision can be achieved, but processing time increases significantly and defective LEDs cannot be accurately identified due to interference from adjacent LEDs
Solution Approach 1:
The patent combines multiple LED testing into a single simultaneous measurement process. By irradiating multiple LEDs with light and collecting photoelectric signals from all LEDs at once using probes, the system achieves parallel processing of multiple measurements, dramatically reducing total processing time while maintaining accuracy through the correction map that accounts for interference patterns.
Solution Approach 2:
The patent employs a correction map generated from reference data to feedback-correct the measured photoelectric signals. The correction map compensates for interference effects and light intensity variations across the irradiation region, allowing accurate identification of defective LEDs even when multiple LEDs are tested simultaneously.
2Productivity
If multiple LEDs are irradiated with light simultaneously and photoelectric signals are collected, then processing time is reduced, but light intensity varies across the irradiation region causing measurement errors
Solution Approach 1:
The patent applies different correction factors to different regions of the irradiation area. The correction map is generated by measuring light intensity at multiple positions and creates region-specific correction data. When measuring multiple LEDs, the system applies the appropriate correction factor based on each LED's position, compensating for light intensity variations across the irradiation region and maintaining measurement accuracy.
3Productivity
If probes are used to collect photoelectric signals from multiple LEDs simultaneously, then testing efficiency improves, but the complexity of the test apparatus increases
Solution Approach 1:
The patent designs the probe system to serve multiple functions: collecting photoelectric signals from multiple LEDs simultaneously, determining which LEDs are defective, and working in conjunction with the correction map system. This multi-functional approach increases productivity while the modular nature of the correction map reduces the complexity burden.
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 significantly reduces processing time, enhances measurement accuracy, and correctly identifies defective LEDs without interference from neighboring LEDs, while being cost-effective and scalable for micro LEDs.
Implementation Method 1
one of a pair of LEDs to be inspected is caused to emit light
Implementation Method 2
optical characteristics of the LED are inspected using a current value of a current output by a photoelectric effect
Data Source
AI summary
A test apparatus includes: an electrical connection unit to be electrically connected to a terminal of each of a plurality of light emitting devices to be tested; a light source unit for collectively irradiating the plurality of light emitting devices with light; a measuring unit for measuring a photoelectric signal obtained by photoelectrically converting light irradiated by the light source unit and output via the electrical connection unit by each light emitting device; an acquisition unit for acquiring a correction map including a correction value for correcting a variation in intensity of light with which a position of each light emitting device is irradiated by the light source unit; and a determination unit for determining a quality of each light emitting device on a basis of a measurement result by the measuring unit and the correction map acquired by the acquisition unit.