Modular LED Lamp Control Circuit for Machine Vision
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Solution Overview
Problem
Current LED array systems for machine vision applications are limited by their inability to address individual LEDs, leading to inefficiencies, high costs, and complexity, especially in large-scale systems requiring high intensity and precise control, due to series or parallel configurations and the need for large power supply units and complex control circuitry.
Innovation Solution
A modular LED lamp with a current-regulating drive circuit using a central processor connected via shift registers to control individual LEDs, employing pulse energy charging to minimize power consumption and utilizing saturated mathematics and SIMD processors for precise PWM control, allowing for flexible and scalable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LEDs are connected in series to maximize brightness-matching, then the variation of brightness of one LED in the series compared to another LED in the series is not visible, but the output voltages can be very high when large numbers of LEDs are used
Solution Approach 1:
The patent divides the large LED array into multiple smaller groups or strings of LEDs. Each string contains a manageable number of LEDs connected in series, allowing individual control and addressing. This segmentation reduces the voltage requirement for each string while maintaining the ability to control large numbers of LEDs collectively or individually through multiple independently controllable strings.
2Power
If LEDs are connected in parallel to reduce maximum string voltage, then the maximum string voltage required is reduced, but power consumption in the balance resistors increases and system efficiency decreases
Solution Approach 1:
The patent employs dynamic control of LED strings through individual addressing and selective activation. Rather than using static parallel connections with balance resistors, the system dynamically enables or disables specific LED strings based on the required pattern and intensity, eliminating the need for continuous power dissipation in balance resistors and improving overall system efficiency.
3Illumination intensity
If strobe control is used to increase LED intensity for high speed inspection, then the intensity from the LED light source is increased for a short defined period of time, but the complexity of the LED control circuitry increases when large numbers of LEDs are required
Solution Approach 1:
The patent implements strobe control by periodically activating LED strings in controlled sequences. The system uses timed pulse signals to illuminate specific LED strings for precise durations, enabling high-speed inspection applications. This periodic activation approach allows intensity control without requiring complex continuous dimming circuitry, simplifying the overall control architecture.
4Adaptability or versatility
If individual LED control is implemented to change LED pattern profile while strobing, then the ability to select which LEDs will be powered is achieved, but the complexity and cost of the LED control circuitry increases
Solution Approach 1:
The patent divides the LED array into multiple independently controllable strings, where each string can be individually addressed and activated. This segmentation enables flexible pattern formation by selectively powering specific strings, achieving adaptability without requiring complex individual LED control circuitry. The modular string architecture simplifies the control system while maintaining versatility.
5Power
If large power supply units are used to support large LED arrays, then the power requirements are met, but the system size increases
Solution Approach 1:
The patent segments the LED array into multiple smaller strings that can be controlled independently. This segmentation allows the power supply to serve multiple smaller groups sequentially or in combination, rather than requiring a single large power supply unit capable of supporting the entire array simultaneously at full power. The modular approach reduces the size and capacity requirements of individual power supply units.
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
The solution enables efficient, cost-effective, and flexible control of large LED arrays, reducing power requirements and system size, while allowing for precise control of strobe profiles and pattern customization, thereby improving image capture in machine vision systems.
Implementation Method 1
the LED has been widely adopted in machine vision inspection systems
Implementation Method 2
the LED light source for a short, defined period of time
Data Source
AI summary
An LED lamp comprising: a plurality of LED strings, each LED string comprising a plurality of LEDs; a plurality of constant current circuits for powering the plurality of LED strings, wherein one constant current circuit is provided for each LED string; a plurality of shift registers for controlling the operation of the plurality of constant current circuits, wherein at least one shift register is provided for each LED string; and a microprocessor for supplying timing pulses to the plurality of shift registers for controlling operation of the plurality of constant current circuits, the timing pulses comprising a plurality of serial bit streams.