Q-NED Pixel Circuit Sensing Ohmic Contact Resistance
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Solution Overview
Problem
Inorganic light emitting diode (Q-NED) display devices face a challenge with ohmic contact resistance deviations between pixels, leading to luminance inconsistencies and potential mura defects due to varying resistances, which affect light emission efficiency and lifespan.
Innovation Solution
A light emitting assembly and display device design that includes a switching transistor, storage capacitor, driving transistor, and sensing transistors to sense and compensate for ohmic contact resistance deviations between Q-NED pixels, utilizing inorganic materials and comb-shaped electrodes to maintain light emission efficiency and extend lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If inorganic light emitting elements (Q-NEDs) are used to maintain luminance stability and extend lifespan, then duration of action is improved, but ohmic contact resistance deviations between pixels cause luminance inconsistencies and mura defects
Solution Approach 1:
The patent performs preliminary sensing of ohmic contact resistance values during a sensing operation before normal display operation. The sensed values are stored and used to compensate for resistance deviations, preventing luminance inconsistencies from occurring during actual display operation. This preliminary measurement and compensation approach resolves the contradiction by addressing the resistance deviation issue before it affects luminance consistency.
Solution Approach 2:
The patent implements a feedback mechanism where ohmic contact resistance values are sensed, stored, and used to adjust driving voltages for each pixel. The sensing transistor measures the resistance, and this information feeds back into the driving circuit to compensate for deviations, ensuring luminance consistency across all pixels while maintaining the lifespan benefits of inorganic materials.
2Measurement precision
If sensing operations are performed to measure ohmic contact resistance, then measurement precision is improved, but device complexity increases due to additional sensing transistors and circuitry
Solution Approach 1:
The patent merges the sensing function with the existing pixel circuit structure by integrating sensing transistors into the pixel circuit. The sensing operation utilizes available circuit elements and combines multiple functions (driving and sensing) within a unified circuit architecture, reducing the overall device complexity while maintaining precise ohmic contact resistance measurement capabilities.
Solution Approach 2:
The patent implements multi-functionality by designing the pixel circuit to perform both normal display driving and sensing operations. The same circuit elements serve dual purposes: the driving transistor drives light emission during display operation, while the sensing transistor measures ohmic contact resistance. This universal design reduces device complexity by avoiding separate dedicated sensing circuits while maintaining precise measurement capabilities.
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 effectively senses and compensates for ohmic contact resistance deviations, preventing mura defects and maintaining light emission efficiency over time by adjusting the data voltage based on sensed resistances, thus enhancing the display device's performance and longevity.
Implementation Method 1
the light emitting elements having an ohmic contact resistance at anodes and cathodes of the light emitting elements
Implementation Method 2
a second sensing transistor that decouples the light emitting elements from a second power supply voltage line in response to an inverted sensing signal
Implementation Method 3
a plurality of light emitting elements that emit light based on the driving current
Data Source
AI summary
A quantum-nano light emitting diode (Q-NED) pixel includes a switching transistor configured to transfer a data voltage in response to a scan signal, a storage capacitor configured to store the data voltage transferred by the switching transistor, a driving transistor coupled to a first power supply voltage line, and configured to generate a driving current based on the data voltage stored in the storage capacitor, a plurality of Q-NEDs configured to emit light based on the driving current, the Q-NEDs having an ohmic contact resistance at anodes and cathodes of the Q-NEDs, a first sensing transistor configured to couple the Q-NEDs to a sensing line in response to a sensing signal when a sensing operation for sensing the ohmic contact resistance of the Q-NEDs is performed, and a second sensing transistor configured to decouple the Q-NEDs from a second power supply line in response to an inverted sensing signal.