On-Chip Micro-LED Fault Detection for Open, Short, and Anode Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro-LED displays face challenges in detecting open and short circuits, as well as LED anode voltage errors, which affect luminance efficiency and uniformity, leading to issues like Mura that can cause unpleasant user experiences.
Innovation Solution
An on-chip component, including a resistor ladder, DAC, and voltage comparator, is used to detect open and short circuits, and anode voltage, with methods to accumulate or shift comparison results for operational diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro-LED size is reduced to μm-level for greater image quality, then pixel density and image quality are improved, but fabrication difficulty and detection complexity increase
Solution Approach 1:
The patent combines multiple detection functions (open circuit detection, short circuit detection, and anode voltage detection) into a single integrated on-chip detection system. The voltage comparator circuit is integrated directly on the display chip, eliminating the need for external detection hardware and simplifying the overall device complexity while maintaining high measurement precision for μm-level micro-LEDs.
2Reliability
If additional detection hardware is added to detect open/short circuits and anode voltage, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The on-chip detection circuit performs multiple functions using a single integrated system: open circuit detection, short circuit detection, and anode voltage detection. The voltage comparator and associated circuitry are designed to handle all three detection tasks simultaneously, eliminating the need for separate detection hardware for each function and reducing overall device complexity.
Solution Approach 2:
The detection system is self-contained and integrated on the same chip as the micro-LED display. The on-chip comparator and detection circuitry use the existing chip resources and signals to perform detection without requiring external test equipment or additional standalone detection components, making the system self-sufficient.
3Ease of operation
If traditional external detection methods are used, then detection flexibility is maintained, but detection efficiency and integration are reduced
Solution Approach 1:
The detection circuit is pre-integrated on the chip during manufacturing, allowing detection capabilities to be built into the device before deployment. This preliminary integration enables the system to perform detection operations efficiently without requiring external setup or additional connection steps, improving detection efficiency while maintaining operational simplicity.
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 efficient detection of operational faults in micro-LED displays without additional hardware, improving luminance uniformity and reducing Mura defects.
Implementation Method 1
a voltage comparator configured to compare the anode voltage of the LED with a plurality of reference voltages from the DAC
Implementation Method 2
a digital to analog converter (DAC) configured to output a plurality of voltages, corresponding to a plurality of digital inputs
Data Source
AI summary
A micro-light-emitting diode (micro-LED) display comprising a plurality of rows of light-emitting diodes (LEDs), each LED of the LEDs in a row including a channel wherein each channel includes a feedback path configured to feed an anode voltage of each LED to an input of a voltage comparator, a column driver comprising a digital to analog converter (DAC) and the voltage comparator, wherein the DAC is configured to receive a plurality of voltage inputs from the resistor ladder and to provide a corresponding plurality of voltage outputs to the input of the voltage comparator, and wherein the voltage comparator is configured to successively compare individual voltage outputs of the plurality of voltage outputs received from the DAC with the anode voltage of each LED, a data latch configured to store comparison results from the voltage comparator.