Display Device Scanning Circuit Instantaneous Current Control
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Solution Overview
Problem
In liquid crystal display devices, polarity-inversion driving to prevent display defects during power-on leads to increased instantaneous current, causing a higher load on the driving circuit and potential faults, especially in high-resolution displays like FHD, which may not meet the required specifications.
Innovation Solution
The implementation of a scanning line driving circuit with a memory circuit that delays the change in control signal FDON from low to high level, preventing sudden changes in gate signals and thus reducing the instantaneous current surge, and applying a voltage identical to the counter-electrode to all signal lines during power-on to ensure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarity-inversion driving is adopted to prevent display defects, then display quality is improved, but instantaneous current increases causing higher load on driving circuit
Solution Approach 1:
The pixel array is divided into multiple banks, and the power supply voltage is applied to different banks at different timings rather than all pixels simultaneously. This segmentation of the power application process reduces the peak instantaneous current while maintaining the polarity-inversion driving benefit for display quality.
Solution Approach 2:
The power supply voltage is applied periodically to different banks in a sequential manner rather than all at once. This periodic application across multiple time periods reduces the instantaneous current surge while ensuring all pixels eventually receive the necessary voltage for proper display operation.
2Stability of the object's composition
If power supply voltage is applied to all pixels at a time of power-on, then display uniformity is improved, but instantaneous current increases causing circuit faults
Solution Approach 1:
The display panel is divided into multiple banks, and the power supply voltage application is segmented across these banks with different timing. This ensures that display uniformity is maintained within each bank while the overall instantaneous current is reduced by avoiding simultaneous voltage application to all pixels.
Solution Approach 2:
Before applying power supply voltage to all pixels, the circuit first applies voltage selectively to specific banks based on their connection status. This preliminary staged action prevents sudden current surges that could cause circuit faults while ultimately achieving uniform display across all pixels.
3Stability of the object's composition
If power supply voltage is applied to all pixels at power-on to ensure uniformity, then display uniformity is improved, but load on driving circuit increases leading to faults
Solution Approach 1:
The driving circuit manages power supply voltage application by segmenting it across multiple banks rather than handling all pixels simultaneously. This reduces the instantaneous load on the driving circuit while maintaining display uniformity through coordinated sequential voltage application to different bank groups.
Data Source
AI summary
According to one embodiment, a display device includes signal lines, scanning lines, pixel switching elements, a signal line driving circuit, a scanning line driving circuit and a display pixel, wherein the signal line driving circuit is configured to apply a voltage, which is identical to a voltage of the counter-electrode, to all the signal lines when a control signal, which is supplied from an outside of the insulative substrate, is at a first logic level, and the scanning line driving circuit is configured to turn on all the pixel switching elements when the control signal is at the first logic level, and to turn off the pixel switching elements at different timings when the control signal is at a second logic level.