Lateral Electric-Field LCD Flicker Control via Parameter Optimization
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Solution Overview
Problem
Liquid crystal display devices, particularly in mobile terminals, face challenges in reducing power consumption while maintaining suitable frame frequencies for displaying moving images without visible flicker, as low-frequency driving methods and intermittent driving methods are not effective for moving images and can cause noticeable flicker at lower frame frequencies.
Innovation Solution
A lateral electric-field type liquid crystal display device with a frame frequency range of 1 Hz to 10 Hz, utilizing TFTs with an off-leak current of 1×10−15 A or less, and resistivity ranges for the liquid crystal and alignment film that satisfy the relationship R1×C1≈R2×C2, where R1 and C1 are the resistance and capacitance of the liquid crystal, and R2 and C2 are the resistance and capacitance of the alignment film, to minimize flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the frame frequency is lowered to reduce power consumption, then power consumption is reduced, but flicker becomes visibly recognized
Solution Approach 1:
The patent applies parameter changes by optimizing the frame frequency to a specific range (1Hz to 10Hz) and controlling the off-leak current of TFTs to 1×10^-15 A or less. This allows the device to operate at low frequencies for reduced power consumption while maintaining acceptable flicker performance through precise parameter control of the liquid crystal and alignment film resistivity relationship (R1×C1≈R2×C2).
Solution Approach 2:
The patent employs preliminary anti-action by pre-controlling the electrical characteristics of the TFTs (off-leak current ≤1×10^-15 A) and establishing the resistivity relationship between liquid crystal and alignment film before operation. This preliminary optimization prevents excessive flicker from occurring even when operating at low frame frequencies for power savings.
2Use of energy by moving object
If the frame frequency is set to 1Hz to 10Hz for low power consumption, then power consumption is reduced, but the ability to display moving images without flicker deteriorates
Solution Approach 1:
The patent changes the operational parameters by defining a specific frame frequency range (1Hz to 10Hz) and establishing precise electrical characteristic thresholds (TFT off-leak current ≤1×10^-15 A, resistivity relationship R1×C1≈R2×C2). These parameter optimizations enable the display to function effectively in the low-frequency regime, expanding its adaptability for power-constrained applications while maintaining acceptable display quality.
3Object-affected harmful factors
If TFT off-leak current is reduced to 1×10^-15 A or less to minimize flicker, then flicker visibility is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by setting a specific target value for TFT off-leak current (≤1×10^-15 A) and establishing the resistivity relationship (R1×C1≈R2×C2) between liquid crystal and alignment film. This parameter specification provides clear manufacturing targets that balance flicker reduction with achievable production precision.
Solution Approach 2:
The patent employs feedback by establishing a controllable relationship (R1×C1≈R2×C2) between liquid crystal and alignment film resistivity. This creates a self-regulating system where the interaction between these two parameters helps maintain stable electrical characteristics, reducing the burden on individual component precision while achieving the overall flicker reduction goal.
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 configuration reduces flicker visibility by controlling luminance fluctuations within acceptable limits, ensuring that the liquid crystal display device maintains low power consumption and effective image display across varying frame frequencies.
Implementation Method 1
an alignment direction of liquid crystal molecules included in a liquid crystal layer held between an upper substrate and a lower substrate is controlled by an electric field generated between a counter-electrode provided in the upper substrate and pixel electrodes provided in the lower substrate
Implementation Method 2
a liquid crystal layer held between an upper substrate and a lower substrate
Data Source
AI summary
According to one embodiment, a lateral electric-field type of liquid crystal display device includes a display panel and a controller, wherein a frame frequency falls within a range of 1 Hz to 10 Hz, an off-leak current of each of the TFTs has a value of 1×10−15 A or less, a resistivity of a liquid crystal and a resistivity of an alignment film both fall within one of a first range and a second range, the first range being 1×1013 to 5×1013 Ω·cm, the second range being 5×1013 to 5×1014 Ω·cm, and a relationship of “R1× C1≈R2×C2” is satisfied, where R1 is a resistance and C1 is a capacity with respect to each pixel, R2 is a resistance and C2 is a capacity with respect to each pixel.