Twisted Nematic LCD Driver Failure Protection
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Solution Overview
Problem
Twisted nematic LCD screens in cockpit displays can become uncontrolled and display a bright, erroneous white screen when row or column drivers fail, leading to visual nuisance and loss of critical information, disrupting pilot operations and safety constraints.
Innovation Solution
A display device with active liquid crystal matrix and electronic control systems that detect incorrect operation and force all pixels to minimum transmission by setting switch-off voltages and GMA voltages to zero, ensuring a black screen even in failure scenarios, using detection means such as fixed image detection or current consumption monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If twisted nematic LCD technology is used to provide optical transmission, then display visibility is improved, but the screen displays a bright white image when uncontrolled, causing visual nuisance and loss of critical information
Solution Approach 1:
The patent applies preliminary anti-action by implementing a monitoring system that detects driver failures before they can cause harmful white screen display. The system proactively identifies when row or column drivers are malfunctioning and preemptively switches to a safe display mode that prevents the white screen phenomenon, thereby counteracting the harmful effect before it occurs.
Solution Approach 2:
The patent implements feedback mechanisms through monitoring circuits that continuously assess the operational status of row and column drivers. When deviations from normal operation are detected (such as abnormal voltage levels or signal patterns), the system receives feedback and automatically adjusts the display output to prevent white screen display, ensuring the harmful effect is countered based on real-time system state.
2Object-affected harmful factors
If automatic switching off of light box is implemented to restore black screen, then visual nuisance is reduced, but complete loss of equipment occurs and screen reconfigurations are disrupted
Solution Approach 1:
The patent applies segmentation by dividing the display system into independent functional units (row drivers, column drivers, light box, monitoring circuits). This modular architecture allows the monitoring system to detect and respond to failures in specific segments without affecting the entire system. When a driver failure is detected, only the affected segment is isolated while other segments remain operational, preventing complete equipment loss.
Solution Approach 2:
The patent implements beforehand cushioning by designing a monitoring and protection system that prepares alternative display modes in advance. When driver failures are detected, the system has pre-planned response mechanisms that switch to safe display configurations, cushioning against the harmful effects of failure without requiring complete system shutdown or causing permanent equipment loss.
3Object-affected harmful factors
If manual switching off of equipment is performed by pilot, then visual nuisance is avoided, but operational time is increased and safety is compromised
Solution Approach 1:
The patent applies self-service by implementing an autonomous monitoring and protection system that detects driver failures and executes protective actions without requiring pilot intervention. The system self-monitors its own operational status, detects anomalies in row or column driver signals, and automatically switches to safe display modes, freeing the pilot from manual intervention and reducing operational time while maintaining safety.
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
Prevents presentation of incorrect images to pilots, minimizes visual disturbance, and maintains operational functionality of dual displays by ensuring one display remains functional even if the other fails, adhering to aeronautical safety requirements.
Implementation Method 1
The potential difference acts on the orientation of the liquid crystal molecules and therefore on their light transmission
Data Source
AI summary
The general field of the invention is that of the display devices that comprise an active liquid crystal matrix of twisted nematic type. The matrix comprises a set of pixels, a set of rows and of columns and an electronic control device. Each pixel is controlled by a transistor. The voltage applied to each control row is either a switch-on voltage VG_on sufficient to switch on the transistors, or a switch-off voltage VG_off sufficient to switch off the transistors. The voltage applied GMA to each column is dependent on the predetermined optical transmission of the pixel. The display device comprises means for detecting the correct operation of the electronic control device. In case of detection of incorrect operation, the display device comprises cut-off means arranged to force to zero the switch-off voltages VG_off of the rows and the GMA voltages of the columns, so that the transmission of all the pixels of the first set is minimum.