Precharge Control Circuit for Display Device Voltage Errors
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Solution Overview
Problem
Existing display devices using capacitive coupling drive systems face issues with precharge errors and image quality due to manufacturing dispersion and temperature fluctuations, leading to high contrast and blurring in initial stages of activation, and require efficient methods to achieve optimal precharge voltage and reduce power consumption.
Innovation Solution
A precharge controlling method involving a voltage generating circuit with a comparator that feeds back the output voltage to control the precharge voltage, ensuring proper voltage levels are reached quickly and reducing errors, while also widening the dynamic range of the output circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the coupling voltage is controlled to obtain optimal value after effective display starts, then manufacturing dispersion and temperature fluctuations are compensated, but precharge errors cause high contrast and blurring in initial activation stage
Solution Approach 1:
The patent applies preliminary action by performing precharge control before the effective display period. A precharge period is inserted prior to normal operation where the coupling voltage is controlled to reach an optimal value in advance, eliminating precharge errors before display begins. This resolves the contradiction by preparing the system beforehand rather than correcting issues during operation.
Solution Approach 2:
The patent implements feedback control during the precharge period by monitoring the coupling voltage and adjusting it to reach the optimal value. The control circuit uses feedback mechanisms to ensure the coupling voltage stabilizes at the correct level before normal display operation starts, thereby eliminating precharge errors without extending the overall activation time.
2Device complexity
If a fixed coupling voltage is used, then the circuit operation is simplified, but manufacturing dispersion and temperature fluctuations reduce yield and deteriorate image quality
Solution Approach 1:
The patent applies dynamics by transitioning from a static fixed coupling voltage to a dynamic controlled coupling voltage. During the precharge period, the coupling voltage is actively controlled to reach an optimal value that compensates for manufacturing dispersion and temperature effects. This dynamic approach maintains image quality consistency while keeping the normal operation period simple and efficient.
3Manufacturing precision
If the precharge time is extended to reduce precharge errors, then image quality improves, but the time required to output normal coupling voltage increases causing picture blurring
Solution Approach 1:
The patent resolves this contradiction by performing the precharge control action preliminarily, before the normal display period begins. The coupling voltage is controlled to reach its optimal value during a dedicated precharge period, allowing sufficient time for error reduction without delaying the start of normal operation. This separates the precharge function from the display function, maintaining both image quality and speed.
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 method enhances precision and shortens the precharge time, improving image quality by achieving optimal coupling voltage levels independently of manufacturing dispersion and temperature, and reduces power consumption by allowing for a wider dynamic range in the output circuit.
Implementation Method 1
pixel portions each of which is composed of a switching element, a liquid crystal pixel cell, and a coupling capacitor Cs
Implementation Method 2
liquid crystal pixel cell... the pixel cell is driven by using a pixel potential obtained by adding the video signal Vsig and the coupling voltage Vcs to each other
Data Source
AI summary
An embodiment of the invention provides a precharge controlling method, including the steps of: providing a voltage generating circuit with an output circuit for outputting a voltage having a necessary level, and a comparator; judging an output voltage from the output circuit in the comparator during a precharge time period, and feeding back an output signal from the comparator to the output circuit; and controlling a precharge voltage until the voltage having the necessary level outputted from the output circuit is reached.