Pixel Circuit Sensing for Real-Time Threshold Compensation
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Solution Overview
Problem
Organic light-emitting display devices face electrical characteristic deviations between pixel circuits, which are not compensated in real time during image display due to external compensation techniques being applied only in power-on or power-off sequences.
Innovation Solution
A pixel circuit design incorporating a second driving element of the same material and structure as the first driving element, with a switch element for sensing, allows threshold voltage sensing during display operation, enabling real-time external compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external compensation is performed in power-on or power-off sequence, then threshold voltage deviations can be compensated, but real-time compensation during display operation cannot be achieved
Solution Approach 1:
The patent applies preliminary action by performing threshold voltage sensing and compensation during the initialization phase (power-on or power-off sequence) before actual display operation begins. The pixel circuit senses the threshold voltage of the driving element and stores compensation values in capacitors during this preliminary stage, ensuring that compensation is ready before real-time display starts, thus achieving accurate compensation without interfering with real-time performance
Solution Approach 2:
The patent uses copying by creating a sensing pixel circuit that replicates the structure and characteristics of the actual driving pixel circuit. The sensing circuit includes a sensing driving element with the same material and structure as the driving element, allowing it to accurately copy and measure the threshold voltage characteristics. This copied sensing circuit enables threshold voltage measurement without directly interfering with the main display function
2Measurement precision
If pixel circuits sense during power-on or power-off sequence, then threshold voltage can be measured, but sensing cannot occur when displaying input images
Solution Approach 1:
The patent applies segmentation by dividing the pixel circuit into two distinct functional parts: a driving pixel circuit for display operation and a sensing pixel circuit for threshold voltage measurement. The sensing circuit is separated with its own sensing driving element, sensing transistor, and sensing capacitor, allowing independent operation during initialization phases without interrupting the main display function of the driving circuit
Solution Approach 2:
The sensing pixel circuit is created as a copy of the driving pixel circuit, using the same organic light-emitting diode structure and driving element material. This copied sensing circuit accurately reflects the electrical characteristics of the driving circuit, enabling precise threshold voltage measurement while the original driving circuit continues its display function without interruption
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 real-time compensation of threshold voltage deviations, improving display performance by reducing electrical characteristic deviations between pixel circuits.
Implementation Method 1
an organic light emitting display device includes a self-luminous organic light emitting diode (hereinafter, referred to as "OLED")
Data Source
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AI summary
The present embodiments relate to a pixel circuit and a display device including the same, and more particularly to a pixel circuit and a display device including the same that are capable of sensing for external compensation when driving a display.