TFT-LCD Power Discharge Circuit for Afterimage Elimination
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Solution Overview
Problem
Afterimage occurs on TFT_LCD screens due to slow discharge of electric charges when the screen is turned off, leading to residual charge and image persistence.
Innovation Solution
A circuit is designed to eliminate afterimage, comprising a power supply unit, an afterimage elimination unit, and a discharge unit. The control unit outputs a first control signal to the discharge unit when the screen is turned off, causing a rapid fall in the first voltage output from the power supply unit, which activates the afterimage elimination unit to discharge electric charges in the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the screen is turned off, then power consumption is reduced, but electric charges discharge slowly causing afterimage
Solution Approach 1:
The control unit detects the turn-off signal in advance and activates the discharge unit before the power supply voltage naturally decays, enabling proactive charge elimination rather than passive waiting. This preliminary action ensures afterimage prevention while maintaining low power consumption during normal off-state.
Solution Approach 2:
The discharge unit utilizes the residual power supply voltage itself to drive the discharge operation, without requiring an external power source. The circuit leverages its own remaining energy to eliminate afterimage, achieving self-service functionality that minimizes additional power consumption.
2Reliability
If a discharge unit is added to reduce voltage quickly, then afterimage is eliminated, but device complexity increases
Solution Approach 1:
The discharge unit is integrated with the existing power supply circuit, sharing common components such as the power supply output node and control logic. This merging approach allows afterimage elimination functionality to be added without creating entirely separate circuitry, thereby limiting the increase in device complexity.
Solution Approach 2:
The power supply unit serves dual functions: normal power delivery during operation and voltage discharge during turn-off. By making the power supply circuit multi-functional, the patent avoids adding dedicated discharge hardware, thus reducing overall circuit complexity while achieving afterimage elimination.
3Loss of energy
If the first voltage falls slowly, then power consumption is low, but the afterimage elimination unit activates late
Solution Approach 1:
The control unit detects the turn-off signal in advance and activates the discharge unit before the power supply voltage naturally decays, enabling proactive charge elimination rather than passive waiting. This preliminary action ensures afterimage prevention while maintaining low power consumption during normal off-state.
Solution Approach 2:
The control unit monitors the power supply voltage level and uses this feedback to determine when to activate the discharge unit. This feedback mechanism ensures the discharge operation starts at the optimal moment - early enough to prevent afterimage but late enough to minimize power consumption during normal operation.
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 circuit quickly activates the afterimage elimination unit to perform a discharge, effectively eliminating afterimage by ensuring rapid reduction of voltage and timely activation of the afterimage elimination unit.
Implementation Method 1
The discharge unit is configured to discharge at the first output end of the power supply unit according to the first control signal to reduce the first voltage
Implementation Method 2
The afterimage elimination unit is configured to discharge electric charge in the screen by means of a second voltage output from the second output end of the power supply unit
Data Source
AI summary
A circuit for eliminating afterimage and a display device. The circuit includes a power supply unit, an afterimage elimination unit and a discharge unit. First and second output ends of the power supply unit are connected with the afterimage elimination unit, respectively. A control end of the discharge unit is configured in electric connection with the control unit, and an execution end of the discharge unit is connected with the first output end of the power supply unit. When the screen is turned off, the control unit outputs a first control signal to the discharge unit. The discharge unit discharges at the first output end of the power supply unit according to the first control signal, so as to expedite a falling of the first voltage output from the first output end of the power supply unit.