LCD Image Signal Correction for Charging Timing Deviations
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Solution Overview
Problem
In liquid-crystal display apparatuses, signal deformation due to electric resistance and wiring capacitance in data and scanning lines leads to timing deviations, resulting in inadequate charging of liquid crystal layers, which deteriorates display quality, especially at high pixel counts and frame rates.
Innovation Solution
A liquid-crystal display apparatus with an image signal correction unit that adjusts grayscale values by determining correction amounts based on the difference between grayscale values of consecutive pixels connected to the same data line, bringing the transmittance of each pixel closer to a desired state to compensate for timing deviations and improve display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of pixels and frame rate are increased, then the display resolution and refresh speed are improved, but the scan period is shortened causing insufficient charging time for liquid crystal layers
Solution Approach 1:
The patent applies preliminary action by adjusting grayscale values in advance based on predicted timing deviations. The image signal correction unit calculates correction amounts before the actual display period, compensating for expected charging insufficient conditions caused by shortened scan periods at high frame rates.
Solution Approach 2:
The patent changes parameters by dynamically adjusting grayscale values based on timing deviation amounts. The correction amount calculation unit computes adjustment values by comparing timing deviations with luminance data, effectively modifying the electrical parameters to compensate for insufficient charging time.
2Measurement precision
If the number of pixels is increased, then the display resolution is improved, but signal deformation due to electric resistance and wiring capacitance increases causing timing deviations
Solution Approach 1:
The patent implements feedback by using timing deviation detection to dynamically adjust grayscale values. The image signal correction unit receives timing deviation information and uses it to calculate correction amounts, creating a closed-loop system that compensates for signal deformation effects in high-resolution displays.
Solution Approach 2:
The patent introduces an intermediary element - the image signal correction unit - that mediates between the original image signal and the display panel. This unit calculates and applies correction amounts based on timing deviations, acting as a buffer that compensates for signal deformation caused by increased pixel counts.
3Speed
If the scan period is shortened to increase frame rate, then the refresh speed is improved, but the liquid crystal layer charging completeness deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and applying correction amounts that counteract the expected insufficient charging effect. Before the display period begins, the system determines timing deviations and adjusts grayscale values in advance, creating a compensatory effect that offsets the shortened charging time at high refresh rates.
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 suppresses display quality deterioration by ensuring accurate transmittance and luminance across pixels, even at high pixel densities and frame rates, by correcting grayscale values and adjusting electric potentials in real-time.
Implementation Method 1
a liquid crystal layer is provided between the pixel electrode and the common electrode... the liquid crystal layer is driven by AC... the transmittance is the same as long as the absolute value thereof is the same
Implementation Method 2
the electric potential of the data line signal is charged to the pixel electrode and the voltage is charged to the capacitance of the liquid crystal layer
Implementation Method 3
a scanning line signal comprising a pulse (an on pulse) to turn on the TFT... the electric potential of the data line signal is charged to the pixel electrode
Data Source
AI summary
A disclosed liquid-crystal display apparatus comprises a display panel comprising a plurality of pixels, a plurality of scanning lines, and a plurality of data lines; and an image signal correction unit to correct a grayscale value determined in accordance with the transmittance the pixel is to have. The image signal correction unit carries out a first correction to bring a first grayscale value farther away from a second grayscale value by a first correction amount determined based on the state of difference between the first grayscale value determined in accordance with the transmittance a first pixel is to have and the second grayscale value determined in accordance with the transmittance a second pixel selected following the first pixel is to have. The first correction is a correction for bringing the transmittance of the first pixel closer to the transmittance according to the first grayscale value.