LCD Common Voltage Switching to Prevent Power-On Flicker
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Solution Overview
Problem
Conventional LCDs experience an instantaneous flickering phenomenon during power-on due to capacitive coupling between data and signal lines, causing abnormal voltage differences across liquid crystal molecules.
Innovation Solution
A display device with a switch controller connected between the common voltage pin and common electrode, activated after a first time point, to control the transmission of data signals and common voltage signals, ensuring stable voltage differences are maintained across liquid crystal molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the common voltage signal is transmitted to the common electrode before the data latch signal is received, then the common electrode can be prepared in advance, but capacitive coupling causes abnormal voltage differences and instantaneous flickering
Solution Approach 1:
The switch controller is configured to turn on the circuit between the common voltage pin and the common electrode after a first time point, which is determined based on the timing of the data latch signal. This preliminary action ensures that the common electrode receives the common voltage signal at the appropriate moment during power-on, avoiding capacitive coupling issues while maintaining display stability.
Solution Approach 2:
The switch controller acts as an intermediary component between the common voltage pin and the common electrode. It controls the transmission of the common voltage signal by turning on the circuit after the first time point, thereby mediating the timing relationship between the common voltage signal and the data latch signal to prevent abnormal voltage differences caused by capacitive coupling.
2Productivity
If the data line transmits invalid voltage before receiving data latch signal, then the source driver can prepare data signals, but capacitive coupling with signal lines causes voltage changes and flickering
Solution Approach 1:
The switch controller serves as an intermediary that controls when the common voltage signal is transmitted to the common electrode. By turning on the circuit after the first time point, it prevents capacitive coupling between data lines and signal lines from causing abnormal voltage changes, thereby eliminating the harmful interference while maintaining signal transmission efficiency.
Solution Approach 2:
The switch controller is configured to delay turning on the circuit between the common voltage pin and the common electrode until after the first time point. This preliminary anti-action prevents the capacitive coupling interference from occurring in the first place, rather than attempting to correct it after it has caused flickering.
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 prevents instantaneous flickering by stabilizing voltage differences, allowing the display to operate normally without flickering upon power-on.
Implementation Method 1
due to capacitive coupling between a data line transmitting an invalid voltage and a signal line transmitting another signal before the operation described above, a voltage on the data line may be changed
Data Source
AI summary
A display device and a driving method thereof are provided. A source driver in the display device is configured to transmit data signals to a plurality of sub-pixels, the data signals including a second data signal (for controlling the brightness of a display panel at the sub-pixels) located after a first time point, a voltage generator in the display device includes a common voltage pin for outputting the common voltage signal, and a switch controller connected between the common voltage pin and the common electrode is configured to turn on a circuit between the common voltage pin and the common electrode after the first time point, thereby improving an instantaneous flickering phenomenon at the time of powering on the display device.