Pixel Circuit With Series Capacitors for Power-Variation Stability
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Solution Overview
Problem
Display devices face issues in maintaining desired image luminance due to variations in voltage of the first driving power, leading to inconsistent image display.
Innovation Solution
A pixel structure incorporating multiple transistors and capacitors, including a first transistor with a double-gate electrode, and capacitors connected in series, to stabilize voltage levels and ensure consistent luminance regardless of driving power variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel structure with single capacitor is used, then the device complexity is low, but the luminance consistency deteriorates due to voltage variation
Solution Approach 1:
The single capacitor is divided into two capacitors (first capacitor and second capacitor) connected in series. This segmentation allows each capacitor to handle a portion of the voltage compensation, improving luminance consistency while distributing the complexity across multiple simpler components rather than one complex capacitor
Solution Approach 2:
The first node is introduced as an intermediary connection point between the two capacitors and the light emitting element. This intermediary node enables the voltage compensation mechanism to function effectively by providing a stable reference point that isolates the light emitting element from voltage variations in the first power line
2Reliability
If voltage compensation mechanism is added, then the luminance consistency improves, but the device complexity increases
Solution Approach 1:
The voltage compensation function is segmented across two capacitors instead of requiring one large complex capacitor. Each capacitor contributes to stabilizing the voltage at different stages, achieving better voltage stability while keeping individual component specifications manageable
Solution Approach 2:
The capacitance values of the first and second capacitors are specifically designed with different parameters (C1 and C2) to optimize voltage compensation. By adjusting these capacitance parameters, the system achieves improved voltage stability tailored to specific operating conditions without requiring excessive complexity
Data Source
AI summary
A pixel includes a first transistor including a first electrode connected to a first power line, a first gate electrode connected to a first node, and a second electrode connected to a second node, a second transistor connected between a data line and the first node, and including a gate electrode connected to a first scan line, a light emitting element including a first electrode connected to the second electrode of the first transistor, and a second electrode connected to a second power line, and a first capacitor and a second capacitor connected in series between the first node and the first electrode of the light emitting element.