Micro LED Pixel Circuit Impedance Compensation and Repair
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Solution Overview
Problem
Micro LED displays are prone to short circuits or open circuits due to particle influence, leading to bright/dark spots and abnormal temperatures, necessitating effective detection and repair of miniature light emitting elements to ensure circuit normalcy.
Innovation Solution
A pixel circuit comprising a first and second lighting circuit, a detection circuit, and a compensation circuit, where the compensation circuit provides a compensation current to light emitting elements based on impedance differences between the circuits to maintain consistent brightness, and a method for detecting and repairing abnormal light emitting elements by determining detection voltages and adjusting driving currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Micro LED elements are used to achieve high brightness and resolution, then display performance is improved, but susceptibility to short circuits and open circuits increases due to particle influence
Solution Approach 1:
The pixel circuit is divided into multiple independent lighting circuits (first lighting circuit with first light emitting element, second lighting circuit with second light emitting element). Each lighting circuit can be independently controlled and detected, allowing the system to maintain functionality even if one element fails due to particle-induced defects.
Solution Approach 2:
The detection circuit performs preliminary detection of each lighting circuit's voltage before full operation. By detecting potential issues (short circuits, open circuits) early through voltage measurement, the system can identify and compensate for defects before they affect display quality, preventing bright/dark spots and abnormal temperature issues.
2Reliability
If multiple light emitting elements are used in the same pixel circuit, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The detection circuit serves multiple functions: it detects voltage in the first lighting circuit, detects voltage in the second lighting circuit, and provides data for impedance calculation. The compensation circuit similarly performs multiple roles by adjusting currents based on impedance differences. This multi-functionality reduces the need for separate dedicated components, thereby managing complexity while maintaining reliability.
Solution Approach 2:
The patent combines the detection and compensation functions into an integrated system where the detection circuit's voltage measurements are directly used by the compensation circuit for impedance calculation and current adjustment. This merging of functions reduces overall system complexity compared to having completely separate detection and correction systems.
3Illumination intensity
If compensation current is provided based on impedance difference, then brightness consistency is improved, but detection precision requirements increase
Solution Approach 1:
The detection circuit acts as an intermediary that measures voltage in each lighting circuit, which then serves as the basis for calculating impedance differences. By using voltage as an intermediate measurable parameter rather than directly measuring impedance, the system achieves the needed precision through voltage detection, which is more easily and accurately measured in this context.
Data Source
AI summary
A pixel circuit includes a first lighting circuit, a second lighting circuit, and a compensation circuit. A first light emitting element of the first lighting circuit receives a first driving current when the first transistor switch of the first lighting circuit is turned on. The second light emitting element of the second light emitting circuit receives a second driving current when the second transistor switch of the second light emitting circuit is turned on. When the first light emitting element and the second light emitting element are driven by the first driving current and the second driving current, the compensation circuit provides a compensation current to the first light emitting element or the second light emitting element according to a difference in impedance between the first light emitting circuit and the second light emitting circuit.