Signal Processing Device for Liquid Crystal Transmittance Control
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Solution Overview
Problem
Liquid crystal panels experience display defects due to poor liquid crystal alignment caused by transverse electric fields, leading to variations in transmittance and perceived display content, which existing techniques fail to adequately address.
Innovation Solution
A signal processing device is employed in liquid crystal apparatuses to detect voltage boundaries between pixels and apply correction voltages dynamically, adjusting the voltage applied to pixels to reduce transverse electric fields and minimize reverse tilt domains by outputting specific signals during different periods, thereby controlling transmittance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant correction voltage is applied to the liquid crystal element during the entire display period, then the reverse tilt domain is reduced, but the transmittance variation increases causing display content different from the original video signal to be perceived by the user
Solution Approach 1:
The patent applies correction voltages periodically at specific timing (rise time period and fall time period) rather than continuously throughout the entire display period. This periodic application suppresses reverse tilt domain formation while limiting transmittance variation to only these specific time windows, preventing noticeable display content changes for the user.
Solution Approach 2:
The patent dynamically adjusts the correction voltage based on the liquid crystal element's state and timing within the display period. The correction voltage is applied selectively during rise time and fall time periods when the liquid crystal molecules are transitioning, rather than applying a static constant voltage throughout the entire display period.
2Reliability
If a correction voltage is applied to suppress reverse tilt domain, then display defects are reduced, but the transmittance of the liquid crystal element varies
Solution Approach 1:
The correction voltage is applied periodically during specific time periods (rise time and fall time) when transmittance variation is less noticeable to users. By concentrating the correction action in these brief windows rather than applying continuous voltage, the patent achieves reverse tilt suppression while minimizing perceived transmittance fluctuations.
Solution Approach 2:
The patent rushes through the correction process during the rise time and fall time periods, applying the correction voltage quickly during these transition phases. This allows the correction to be completed before the display period stabilizes, minimizing the duration during which transmittance variation occurs.
3Productivity
If the liquid crystal element is driven at high speed, then productivity is improved, but reverse tilt domain occurs due to insufficient alignment time
Solution Approach 1:
The patent applies correction voltages in advance during the rise time period before the main display period begins. This preliminary action ensures that the liquid crystal molecules are properly aligned before the high-speed display cycle completes, preventing reverse tilt domain formation even at high driving speeds.
Solution Approach 2:
The patent uses feedback from the display timing signal to determine when to apply correction voltages. By monitoring the display period timing and applying correction voltages during specific phases (rise time and fall time), the system adapts the correction timing to match the high-speed driving cycle, ensuring proper alignment is achieved within each cycle.
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 approach effectively suppresses transmittance variations and reduces reverse tilt domains, improving display quality by balancing correction voltage application based on pixel voltages and temperatures, ensuring minimal perceived changes in display content.
Implementation Method 1
a liquid crystal element 120, and a common electrode 108. In this liquid crystal panel, there are cases where poor liquid crystal alignment (reverse tilt domain) occurs due to a transverse electric field generated between pixels adjacent to each other
Implementation Method 2
there are cases where poor liquid crystal alignment (reverse tilt domain) occurs due to a transverse electric field generated between pixels adjacent to each other
Data Source
AI summary
A signal processing device of a liquid crystal apparatus detects a boundary between a first pixel to which a first voltage lower than a first reference voltage is applied and a second pixel to which a second voltage higher than a second reference voltage is applied on the basis of a signal for controlling a voltage applied to pixels, corrects a signal correlated with M pixels including the first pixel to a third voltage which is higher than the first voltage and lower than the second voltage, outputs the third voltage as an applied voltage to the M pixels in a first period, outputs the first voltage as an applied voltage to the M pixels in a second period, and outputs the third voltage as an applied voltage to the M pixels in a third period.