Liquid Crystal Display Flicker Suppression via Area Modulation
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Solution Overview
Problem
Display devices for mobile appliances face challenges in reducing power consumption while minimizing flicker occurrence, especially when driven at low frame rates below 60 Hz.
Innovation Solution
A liquid crystal display panel with a driver circuit that employs area coverage modulation and normally black mode, using a liquid crystal layer, pixel electrodes, phase difference layers, and a polarizing plate to modulate lighting areas at a frame rate less than 60 Hz, suppressing flickers by maintaining stable luminance regardless of voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display device is driven at a low frame rate (less than 60 Hz) to reduce power consumption, then power consumption is reduced, but flicker occurrence increases
Solution Approach 1:
Each pixel electrode is divided into multiple partial electrodes (first through fourth partial electrodes). By selectively applying voltage to different combinations of these partial electrodes, the display achieves gray-scale representation through area coverage modulation. This segmentation enables stable luminance control at low frame rates by precisely controlling the illuminated area of each pixel, thereby reducing flicker while maintaining low power consumption.
Solution Approach 2:
The display device employs frame inversion driving where the polarity of voltages applied to pixel electrodes is inverted between consecutive frames. This periodic action stabilizes the liquid crystal alignment and maintains consistent luminance output across frames, preventing flicker even when operating at low frame rates below 60 Hz.
2Use of energy by moving object
If area coverage modulation is used to achieve gray-scale display at low frame rates, then power consumption decreases, but luminance stability becomes more difficult to maintain
Solution Approach 1:
A constant voltage is applied to all pixel electrodes (or groups of pixel electrodes) during each frame period, ensuring that the electric field strength remains uniform across the display panel. This equipotential approach maintains consistent liquid crystal alignment and luminance output across all pixels, preventing luminance instability even when using area coverage modulation at low frame rates.
Solution Approach 2:
Frame inversion driving periodically inverts the voltage polarity between frames, which compensates for any drift or instability in liquid crystal alignment. This periodic correction maintains luminance stability across frames, ensuring consistent display quality throughout operation.
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 achieves low power consumption while effectively preventing flickers, even at low frame rates, by ensuring stable luminance and reducing flicker prominence in the display device.
Implementation Method 1
a liquid crystal layer, a plurality of pixel electrodes... The pixel electrodes are provided in a region facing the liquid crystal layer and apply a voltage to the liquid crystal layer
Implementation Method 2
a phase difference layer and a polarizing plate... The phase difference layer and the polarizing plate are provided on a side, relative to the liquid crystal layer, which ambient light enters
Data Source
AI summary
A display device includes: a liquid crystal display panel; and a driver circuit that drives the liquid crystal display panel. The liquid crystal display panel includes a liquid crystal layer, pixel electrodes provided in a region facing the liquid crystal layer and which apply a voltage thereto, and a phase difference layer and a polarizing plate each provided on a side, relative to the liquid crystal layer, which ambient light enters. Each of the pixel electrodes includes a plurality of partial electrodes, and the driver circuit selects one or more partial electrodes from the partial electrodes to which a constant voltage is to be applied in accordance with an image signal. The constant voltage causes the liquid crystal display panel to be in a white state. The driver circuit performs gray-scale display by modulating lighting area of each pixel at a frame rate of less than 60 Hz.