Pixel Circuit With Series Capacitors to Suppress Display Crosstalk
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Solution Overview
Problem
Conventional pixels in display apparatuses suffer from increased sensitivity of driving transistors, leading to crosstalk and display defects such as touch noise and cycle mura due to the ratio between storage and hold capacitors affecting gate-source voltage swing width.
Innovation Solution
A pixel design incorporating a first and second capacitor connected in series, with a seventh switching element applying a reference voltage to the node between them, allowing direct application of data voltage and reducing sensitivity by matching the swing range of data voltage and gate-source voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the data voltage swing width is increased to improve display brightness and contrast, then the gate-source voltage of the driving transistor becomes larger than the swing width, reducing transistor sensitivity. However, if the data voltage swing width is decreased to match the gate-source voltage, then transistor sensitivity increases causing crosstalk and display defects
Solution Approach 1:
The patent divides the voltage application path into two segments: a first voltage application path for the light emitting element and a second voltage application path for the driving transistor gate. By applying data voltage through the first capacitor in the first path and through the second capacitor in the second path, the patent independently controls the voltage swing width for each path, allowing optimization of both display brightness and transistor sensitivity without mutual interference
Solution Approach 2:
The patent introduces capacitors as intermediary components between the data voltage source and the voltage application points. The first capacitor connects to the light emitting element anode while the second capacitor connects to the driving transistor gate. These intermediaries enable independent voltage control for each path, preventing direct coupling that would cause crosstalk while maintaining proper voltage swings for display quality
2Stability of the object's composition
If the storage capacitor to hold capacitor ratio is increased to improve voltage retention, then the gate-source voltage swing width increases, reducing transistor sensitivity. However, if the ratio is decreased to reduce voltage swing, then transistor sensitivity increases causing touch noise and cycle mura
Solution Approach 1:
The patent segments the voltage retention function into two independent paths: one for the light emitting element (first capacitor) and one for the driving transistor gate (second capacitor). Each path can be optimized independently - the first capacitor maintains voltage for brightness while the second capacitor's smaller size ensures proper gate voltage swing width, preventing sensitivity-induced defects
Solution Approach 2:
The patent applies different capacitor sizes to different locations in the circuit based on local requirements. The first capacitor is sized for optimal voltage retention in the light emitting element path, while the second capacitor is sized to provide appropriate voltage swing for the driving transistor gate, ensuring local optimization of each component's performance without compromising the other
Data Source
AI summary
A pixel includes a light emitting element, a first switching element connected to a first node, a second node, and a third node, a first capacitor connected to the first node and a fourth node, a second capacitor connected to the fourth node and the third node, a second switching element applying a data voltage to the first capacitor, a third switching element applying a reference voltage to the first node, a fourth switching element receiving an initialization gate signal and an initialization voltage and connected to an anode electrode of the light emitting element, a fifth switching element receiving a first emission signal, a first electrode and a first power voltage and connected to the second node, a sixth switching element receiving a second emission signal and connected to the third node and the anode electrode, and a seventh switching element applying the reference voltage to the fourth node.