AMOLED Array Substrate Rapid Charge Discharge Control
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Solution Overview
Problem
Active matrix organic light emitting diode (AMOLED) displays experience shutdown image sticking due to charges left on pixel capacitors during power-off, causing residual images.
Innovation Solution
An array substrate with a control unit connected to the scanning and data driving units, which rapidly discharges charges through data lines when the display is powered off, using transistors and a timer to ensure all pixel units are turned on and power lines are grounded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If AMOLED uses active matrix driving mode with pixel capacitors to store charges, then display response time and viewing angle are improved, but shutdown image sticking occurs due to residual charges remaining on capacitors during power-off
Solution Approach 1:
The patent applies preliminary action by introducing a discharge transistor that is pre-configured in the pixel circuit but remains inactive during normal operation. When power is turned off, this pre-prepared discharge path is activated to rapidly remove residual charges from the pixel capacitor, preventing shutdown image sticking before it can manifest as a display defect.
Solution Approach 2:
The patent extracts the harmful residual charges from the pixel capacitor by providing a dedicated discharge path through the discharge transistor connected between the capacitor and ground. This separation allows the capacitor to maintain its charging function during operation while enabling independent charge removal during power-off, eliminating the harmful effect without affecting normal display performance.
2Loss of time
If traditional PMOLED reduces driving time for individual pixels as display size increases, then power consumption is reduced, but transient current must be increased causing great rise in power consumption
Solution Approach 1:
The patent enables continuity of useful action by maintaining the pixel capacitor's charge storage capability throughout the display's operational lifecycle. The discharge transistor provides a controlled mechanism to remove charges only when necessary (during power-off), allowing the capacitor to continuously serve its display function during operation without requiring repeated charging cycles, thus reducing overall power consumption.
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 eliminates shutdown image sticking by rapidly discharging residual charges, improving display quality and preventing image retention.
Implementation Method 1
by applying certain electric fields to an anode and a cathode at two sides of an electroluminescent layer, being driven by the electric fields, electrons and holes are transferred
Implementation Method 2
charges stored in the pixel units being rapidly discharged through the data lines
Data Source
AI summary
An array substrate includes: a scanning driving unit for providing a row scanning signal to a plurality of gate lines, and a data driving unit for providing a data signal to a plurality of data lines, the plurality of gate lines and the plurality of data lines being horizontally and vertically crossed to form an array of pixel units arranged in an matrix form, and further including: a control unit electrically connected with the scanning driving unit and the data driving unit respectively, for controlling the scanning driving unit turn on each of the pixel units when the display device is powered off, such that charges stored in the pixel units are rapidly discharged through the data lines, so as to eliminate the shutdown image sticking of the AMOLED display. There have disclosed also a method for driving array substrate and a display device.