LED Driving Device Pixel Defect Detection
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Solution Overview
Problem
Existing display devices, such as OLEDs, face challenges in supersizing beyond 10 meters in width due to increased manufacturing costs and maintenance complexities, particularly in detecting and addressing defective pixels and short circuits in large LED display devices.
Innovation Solution
A light emitting diode (LED) driving device comprising a driving circuit and a protection circuit that senses and compares forward-direction voltages of LEDs to determine pixel defects, short circuits, and incomplete short circuits, using a comparator with a hysteresis loop and adjusting brightness through pulse width modulation (PWM) signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If display devices are supersized to more than 10 meters in width using LED display technology, then the panel size and manufacturing flexibility are improved, but the cost of manufacturing increases and maintenance complexity increases
Solution Approach 1:
The protection circuit performs preliminary detection of pixel defects and short circuits by continuously monitoring forward voltage during normal operation. This preliminary action enables early identification of problematic pixels before they cause system failure, allowing for proactive maintenance rather than reactive repairs.
Solution Approach 2:
The system performs self-diagnosis through automated pixel detection and status determination. The protection circuit automatically identifies defective pixels and generates appropriate signals without requiring external inspection, enabling the display device to monitor and report its own health status independently.
2Area of stationary object
If display devices are supersized to more than 10 meters in width using LED display technology, then the panel size and manufacturing flexibility are improved, but the cost of manufacturing increases
Solution Approach 1:
The protection circuit performs preliminary detection of pixel defects and short circuits by continuously monitoring forward voltage during normal operation. This preliminary action enables early identification of problematic pixels before they cause system failure, allowing for proactive maintenance rather than reactive repairs.
Solution Approach 2:
The system performs self-diagnosis through automated pixel detection and status determination. The protection circuit automatically identifies defective pixels and generates appropriate signals without requiring external inspection, enabling the display device to monitor and report its own health status independently.
3Measurement precision
If protection circuits continuously monitor all pixels to detect defects and short circuits, then the detection accuracy is improved, but the device complexity and power consumption increase
Solution Approach 1:
The protection circuit uses a universal detection mechanism that leverages the existing forward voltage characteristics of LEDs during normal operation. By using the same voltage sensing path for both driving and detection purposes, the circuit achieves multi-functionality without requiring separate dedicated detection hardware for each pixel.
Solution Approach 2:
The system performs self-diagnosis through automated pixel detection and status determination. The protection circuit automatically identifies defective pixels and generates appropriate signals without requiring external inspection, enabling the display device to monitor and report its own health status independently.
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 effective detection and identification of defective pixels and short circuits in LED display devices, reducing maintenance costs and improving the reliability of supersized displays by accurately determining the state of each pixel.
Implementation Method 1
a protection circuit to sense a first voltage corresponding to a forward-direction voltage of a first LED among the plurality of LEDs in a first time, to sense a second voltage corresponding to a forward-direction voltage of a second LED among the plurality of LEDs in a second time
Implementation Method 2
The protection circuit may input the first voltage and the second voltage into a comparator comprising a hysteresis loop and determine whether or not each pixel is defective according to an output from the comparator
Implementation Method 3
the driving circuit may comprise a switch to adjust brightness of each pixel according to a pulse width modulation (PWM) signal
Data Source
AI summary
The present disclosure relates to a technology for driving an LED, comprising sensing a forward-direction voltage of an LED and determining whether or not the LED is defective by comparing the forward-direction voltage with a comparative object voltage, wherein the comparative object voltage is continuously updated using a sensed forward-direction voltage so that the comparative object voltage may be set to be an unfixed value, that is, a value reflecting a current state of an LED. This allows a more accurate detection of a defect of an LED.