Pixel Circuit Timing for Low-Grayscale Flicker Suppression
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Solution Overview
Problem
Display panels exhibit flickering at lower grayscales due to incomplete discharge of node potentials, leading to unstable light emission.
Innovation Solution
Extend the duration of time periods between non-light-emission stages and preset stages to ensure complete discharge of node potentials, reducing the influence of parasitic capacitance and stabilizing electrode potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display panel operates at lower grayscales with standard timing, then power consumption is reduced, but the display screen flickers due to incomplete discharge of node potentials
Solution Approach 1:
The patent introduces a preset stage before the light emission stage where the compensation module is activated to discharge node potentials in advance. This preliminary discharge action ensures that when the light emission stage begins, the nodes are properly discharged, preventing flicker during actual display operation at lower grayscales and refresh rates.
Solution Approach 2:
The working process is divided into distinct stages: non-light-emission stage, preset stage, and light emission stage. By segmenting the operation timeline and inserting a dedicated preset stage with specific timing requirements (L1>W1 and Ln>Wn), the patent separates the discharge function from the light emission function, allowing proper potential discharge without extending the actual display time.
2Productivity
If the refresh rate is reduced to save power, then energy consumption decreases, but the display flickers more due to insufficient time for potential discharge
Solution Approach 1:
By performing the potential discharge action in advance during the preset stage before each light emission stage, the patent ensures that even at lower refresh rates, the nodes have sufficient time (L1>W1 and Ln>Wn) to discharge completely before the next display cycle begins, preventing flicker regardless of refresh rate.
Solution Approach 2:
The patent dynamically adjusts the timing parameters L1 and Ln to be greater than W1 and Wn respectively, creating flexible time buffers that adapt to different refresh rates and grayscale levels, ensuring stable display performance across varying operating conditions.
3Reliability
If the time period for potential discharge is extended, then display stability improves, but the overall cycle time increases
Solution Approach 1:
The patent segments the cycle time into non-light-emission stage, preset stage, and light emission stage, allowing the discharge time (L1 and Ln) to be extended within the non-light-emission portion without increasing the actual light emission duration, thus maintaining display stability without proportionally increasing total cycle time.
Solution Approach 2:
By changing the timing parameters to satisfy L1>W1 and Ln>Wn, the patent optimizes the distribution of time across different stages, extending the discharge time buffer without linearly increasing the overall cycle time, as the extended time is utilized during the non-light-emission period when the display is not actively showing content.
Data Source
AI summary
Provided are a display panel including a pixel circuit and a light-emitting element. The pixel circuit includes a drive module, a light emission control module, and a compensation module. The drive module includes a drive transistor. The light emission control module includes a first light emission control module and a second light emission control module, where the first light emission control module is connected between a first power signal line and the drive transistor, and the second light emission control module is connected between the drive transistor and the light-emitting element. The compensation module is connected between the gate and the second electrode of the drive transistor, and a time period during which the compensation module is on is a preset stage. In a light emission stage, the light emission control module is on; and in a non-light-emission stage, at least the second light emission control module is off.