Display Shutdown Control for Pixel Charge Discharge
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Solution Overview
Problem
Conventional display devices experience image flickering due to residual charges in pixels when shut down, which degrade display quality upon subsequent power-on.
Innovation Solution
A display device with a shutdown detection circuit that monitors voltage states of power supply, input power, and gate high voltage, initiating a shutdown process by grounding source driving signals and applying a high voltage pulse to gate scan signals, ensuring pixels are discharged to reference ground voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the display device is shut down without discharging pixel charges, then power consumption is reduced, but residual charges cause image flickering and degrade display quality upon next power-on
Solution Approach 1:
The patent applies preliminary action by initiating a pixel charge discharge operation during the shutdown process before the display device is fully powered off. The controller detects the shutdown state and activates a discharge mechanism that applies a discharge voltage to pixel electrodes through the liquid crystal layer, ensuring residual charges are eliminated before power consumption is reduced. This preliminary discharge action prevents image flickering upon next power-on while still achieving energy savings.
2Reliability
If a pixel charge discharge operation is performed during shutdown, then display quality is improved by eliminating residual charges, but device complexity increases due to additional control circuits
Solution Approach 1:
The patent applies universality by designing the liquid crystal display device to perform multiple functions using existing components. The same liquid crystal layer and electrode structures used for normal display operation are utilized for charge discharge during shutdown. The controller integrates both display control and shutdown discharge control functions, eliminating the need for separate dedicated discharge circuits. This multi-functional approach improves display quality while minimizing additional device complexity.
Solution Approach 2:
The patent applies self-service by enabling the display device to discharge its own pixel charges using its existing liquid crystal layer and electrode structures. The controller utilizes the inherent electrical properties of the liquid crystal material and existing electrode connections to create a discharge path, rather than requiring external discharge equipment or complex additional circuitry. The system serves itself by repurposing its own components for the discharge function.
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
Effectively discharges residual charges in pixels, preventing image flickering and enhancing display quality by ensuring complete discharge during shutdown.
Implementation Method 1
The power supply circuit receives an input power, and generates a power supply voltage, a gate high voltage and the common voltage according to the input power
Implementation Method 2
the gate driver generates the gate scan signals with a high voltage pulse, and the power supply circuit makes the common voltage to be equal to the reference ground voltage
Data Source
AI summary
A display device and a shutdown control method thereof are provided. In the display device, a display panel has multiple pixels. A power supply circuit generates a power supply voltage, a gate high voltage and a common voltage according to an input power. A gate driver generates gate scan signals, and a source driver provides source driving signals to drive the display panel. A shutdown detection circuit detects a variation state of voltages values of the power supply voltage, the input voltage and the gate high voltage, and starts a shutdown process when the variation state is a decreasing state. In the shutdown process, the source driver makes the source driving signals to be equal to a reference ground voltage, the gate driver generates the gate scan signals with a high voltage pulse, and the power supply circuit makes the common voltage to be equal to the reference ground voltage.