Active-Matrix LCD Using Resistive Memory for Voltage Control
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Solution Overview
Problem
Active matrix liquid crystal displays (AM LCDs) face issues with capacitor charge leakage, requiring constant regeneration, especially when storing analog information, and they do not eliminate line-by-line flicker.
Innovation Solution
The use of controlled resistors with memory, specifically memristors or magneto-resistive elements, as memory elements instead of capacitors, with a voltage divider for controlling liquid crystals, allowing for reliable voltage storage and image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitors are used as memory elements in active matrix LCD, then voltage storage is achieved, but charge leakage occurs requiring constant regeneration
Solution Approach 1:
The patent changes the fundamental parameter of the memory element from capacitor (charge-based) to resistor (resistance-based). Specifically, it uses memristors whose resistance state directly encodes the voltage level, eliminating the charge leakage problem inherent in capacitive storage while maintaining voltage storage capability.
Solution Approach 2:
The patent replaces the electrical charge storage mechanism (capacitor) with a resistance-based storage mechanism (memristor). This substitution fundamentally changes how voltage information is stored, using the resistive state of the memristor to maintain voltage levels without continuous energy input.
2Ease of operation
If capacitors are used for voltage storage in AM LCD, then pixel control is enabled, but line-by-line flicker effect is preserved
Solution Approach 1:
The patent enables simultaneous address and data signal application to all pixels through the resistive memory architecture. This allows the display to operate without the sequential line-by-line scanning that causes flicker, achieving continuous image update across the entire display at once.
3Loss of information
If capacitors are used as memory elements, then voltage encoding is achieved, but constant regeneration is required especially for analog information
Solution Approach 1:
The patent employs memristors that can be easily rewritten and do not require complex regeneration circuits. The resistive memory elements can be rapidly reconfigured to store new analog values without the need for lengthy charge discharge cycles, enabling efficient analog information storage and updates.
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
This solution provides a reliable method for controlling liquid crystals, reducing the need for constant capacitor regeneration and minimizing line-by-line flicker, thereby enhancing image quality and stability.
Implementation Method 1
each liquid crystal (LC) cell is controlled by a voltage supplied from a Resistive Voltage Divider with Memory (MRVD). The memory stores the value of the divider resistances that determines the voltage controlling the liquid crystal (LC) cell.
Implementation Method 2
The preferred embodiment is illustrated in FIG. 3, where Ri is the address channel, Dj is the data channel, MRVD is the Resistive Voltage Divider with Memory, and LC is the Liquid Crystal Cell.
Implementation Method 3
this embodiment comprises elements utilizing a magneto-resistive effect, that is, utilizing magneto-resistive elements, wherein the memory is stored in the form of magnetic domains controlling the resistance of the elements as controllable memory resistors.
Data Source
AI summary
An active-matrix liquid crystal display (AM LCD), which uses controlled resistors with memory instead of capacitors as memory elements for pixels. The voltage control on the liquid crystal cell is performed by means of a voltage divider on the controlled resistors.