Display Apparatus Timing Controller for Low Gray Scale Afterimage Reduction
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Solution Overview
Problem
Liquid crystal display apparatuses using the photo-alignment method suffer from afterimages due to AC and DC voltage effects, particularly noticeable in low gray scale displays, which affect image quality and visibility.
Innovation Solution
A display apparatus and method that includes a timing controller converting black and low gray scale image signals to specific polarities relative to a common voltage, with temperature-dependent data value conversion to minimize afterimage effects, utilizing a data processing unit that measures temperature and adjusts signal polarities to reduce DC accumulation phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the photo-alignment method is used to align liquid crystal molecules, then the contrast ratio is improved, but AC afterimage and DC afterimage are generated due to alignment layer deformation and ion particle accumulation
Solution Approach 1:
The patent applies preliminary action by pre-processing the image data before display. Specifically, it detects low gray scale regions in the image and applies gamma correction or other processing techniques to these regions beforehand, preventing afterimage generation at the source rather than attempting to correct it after display
Solution Approach 2:
The patent changes parameters by dynamically adjusting gamma values or luminance parameters for low gray scale regions based on temperature detection. The system modifies display parameters adaptively to compensate for temperature-induced afterimage effects while maintaining overall image quality
2Stability of the object's composition
If DC voltage is applied to pixel electrodes, then the liquid crystal molecules are aligned, but ion particles accumulate on the pixel electrode causing DC afterimage
Solution Approach 1:
The system performs preliminary detection of low gray scale regions and applies preventive processing before the DC voltage is applied during normal display operation, thereby preventing ion accumulation effects before they occur
Solution Approach 2:
The patent implements feedback mechanisms by detecting temperature changes and adjusting display parameters accordingly. The system continuously monitors temperature and modifies gamma values or luminance parameters to compensate for ion accumulation effects that occur at different temperatures
3Reliability
If the display operates at low surrounding temperature, then the display function is maintained, but the afterimage becomes more prominent in low gray scale displays
Solution Approach 1:
The patent applies dynamics by making the display system adaptive to temperature changes. It detects temperature conditions and dynamically adjusts gamma values or luminance parameters for low gray scale regions, allowing the system to maintain optimal performance across different temperature conditions
Solution Approach 2:
The system changes parameters adaptively by modifying gamma values, luminance thresholds, or other display parameters based on detected temperature conditions, thereby compensating for temperature-induced afterimage effects while maintaining display reliability
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
The solution effectively reduces afterimage issues by optimizing voltage levels and polarities based on temperature, ensuring consistent luminance across pixels and improving image quality, especially in low gray scale displays.
Implementation Method 1
Liquid crystal molecules in the liquid crystal layer may be aligned in a predetermined direction in the absence of an electric filed by using a photo-alignment method in which an alignment layer is treated with ultraviolet (UV) light.
Implementation Method 2
the liquid crystal molecules are aligned in parallel to a substrate and rotate almost parallel to the substrate when driven
Data Source
AI summary
A display apparatus includes a timing controller for converting data values of black image signals to have one polarity with respect to a common voltage and for converting data values of low gray scale image signals to have one polarity with respect to the common voltage, a data driver for converting the image signals outputted from the timing controller into data voltages, and a plurality of pixels for receiving the data voltages in response to gate signals to display an image. The low gray scale image signals displays a gray scale equal to or less than a reference gray scale at a surrounding temperature lower than a reference temperature.