LED Illumination Module for High-Speed Inspection
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Solution Overview
Problem
Conventional strobe illumination systems using discharge lamps face limitations in pulse duration and frame rate due to the long fall time of these lamps, which restricts the maximal possible pulse rate and results in image smear during high-speed imaging applications.
Innovation Solution
The use of high current short duration driving signals for light emitting diodes (LEDs) to generate high-intensity light pulses, allowing for independent control of multiple LED groups arranged in ring or concentric ring formations, with optics for directing light pulses to achieve collimated, filtered, and homogenized illumination, enabling faster scanning speeds and improved control over pulse duration and shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If discharge lamps are used for strobe illumination, then illumination intensity can be achieved, but pulse duration cannot be shortened below 10 μS due to long fall time
Solution Approach 1:
The patent changes the fundamental parameter of light source response time by transitioning from discharge lamps (10 μS fall time) to LEDs (sub-μS response), enabling pulse durations below 1 μS while maintaining illumination intensity through high current driving signals
2Productivity
If discharge lamps with long fall time are used, then illumination can be provided, but maximal pulse rate is limited resulting in image smear
Solution Approach 1:
The patent changes the temporal parameter of illumination by using LEDs with rise and fall times in the sub-μS range, enabling pulse rates exceeding 500 kHz compared to discharge lamps limited to lower frequencies, thereby achieving high scanning speeds without image smear
Solution Approach 2:
The patent implements periodic pulsed illumination using LEDs synchronized with the scanning process, where each pulse is precisely timed and duration-controlled to capture periodic positions of the scanned object without motion blur
3Duration of action of moving object
If high current short duration driving signals are applied to LEDs, then pulse duration can be reduced to 250 ns, but current exceeds maximal allowable continuous current
Solution Approach 1:
The patent applies periodic pulsed driving signals to LEDs where the duty cycle is kept low enough that the average power remains within safe operating limits, while peak currents during pulses are high enough to achieve sub-μS pulse durations and sufficient illumination intensity
Solution Approach 2:
The patent incorporates preliminary thermal management design including heat sinks and thermal pathways to pre-cool the LED junctions between pulses, preventing cumulative thermal stress even when operating with high peak currents that exceed continuous rating
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 allows for higher scanning speeds, better control over light pulse characteristics, and improved illumination uniformity and intensity, overcoming the limitations of discharge lamps by enabling pulse durations as short as 250 ns and maintaining high illumination intensity, thus enhancing the performance of inspection systems.
Implementation Method 1
a group of light emitting diodes (LEDs) that may include at least one LED; the group of LED may be coupled to the LED driver; wherein the LED driver may be arranged to activate the group of LEDs by driving a high current short duration driving signal; and wherein the group of LEDs may be arranged to emit at least one light pulse in response to the high current short duration driving signal
Data Source
AI summary
An illumination module that may include a LED driver; a group of light emitting diodes (LEDs) that comprises at least one LED; the group of LED is coupled to the LED driver; wherein the LED driver is arranged to activate the group of LEDs by driving a high current short duration driving signal; and wherein the group of LEDs is arranged to emit at least one light pulse in response to the high current short duration driving signal.