Liquid Crystal Display Overdrive and Light Modulation for Motion Blur Reduction
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Solution Overview
Problem
Liquid crystal displays (LCDs) suffer from blurred edges of moving objects due to persistence of vision and slow response time, leading to poor motion picture quality, as human eyes perceive edges as blurred due to the persistence of vision and slow response time of the display.
Innovation Solution
The method involves overdriving pixel circuits and modulating light to achieve a predetermined level of uniformity, adjusting the phase and amount of overdrive to ensure that the modulated light reaches the desired luminance within a short frame period, thereby reducing blurring and improving motion picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If overdrive voltage is applied to pixel circuits to reduce response time, then motion picture response time is shortened, but luminance uniformity deteriorates due to non-uniform light modulation
Solution Approach 1:
The patent applies periodic light modulation to the pixel circuits, where light is modulated at specific frequencies (e.g., 100Hz or 200Hz) during the overdrive period. This periodic action creates multiple luminance peaks that can be controlled to achieve uniformity while maintaining fast response. The light modulation is synchronized with the overdrive voltage application, creating a coordinated periodic stimulus that resolves the contradiction between speed and uniformity.
Solution Approach 2:
The patent dynamically adjusts the overdrive voltage level and light modulation parameters based on the desired response time and uniformity requirements. The overdrive voltage is applied temporarily for a specific duration and then removed, allowing the pixel to settle to the target gray level. This dynamic control enables the system to achieve fast response during the overdrive phase while maintaining luminance uniformity in the final state.
2Loss of time
If overdrive voltage is applied to pixel circuits to reduce response time, then motion picture response time is shortened, but image quality deteriorates due to double edges and non-uniform luminance peaks
Solution Approach 1:
The patent employs feedback control by monitoring the luminance output and adjusting the overdrive voltage and light modulation parameters accordingly. The system measures the actual luminance peaks and compares them with the desired uniform peaks, then adjusts the control parameters to minimize deviations. This feedback mechanism eliminates double edges and ensures uniform luminance peaks, thereby maintaining high image quality while achieving fast response times.
Solution Approach 2:
The patent changes multiple parameters including overdrive voltage level, light modulation frequency, and duty cycle to optimize both response time and image quality. By adjusting these parameters, the system can control the shape and uniformity of luminance peaks, preventing double edge artifacts and ensuring that the transition from one gray level to another is smooth and uniform, thus maintaining high image quality.
3Stability of the object's composition
If light modulation is applied during overdrive, then luminance uniformity is improved, but device complexity increases due to coordination requirements
Solution Approach 1:
The patent merges the light modulation function with the existing pixel circuit overdrive function, so that a single control signal performs dual purposes: driving the pixel circuit and modulating the light. This integration reduces the need for separate control circuits and simplifies the overall system architecture, thereby reducing device complexity while maintaining luminance uniformity.
Solution Approach 2:
The control circuit is designed to perform multiple functions: generating overdrive voltage, modulating light intensity, and synchronizing these operations. This multi-functional approach eliminates the need for separate dedicated circuits for each function, reducing overall device complexity while achieving the desired luminance uniformity through coordinated control.
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 reduces blurring and improves the overall quality of motion images by shortening the motion picture response time and enhancing the clarity of edges, resulting in sharper and more defined motion images.
Implementation Method 1
overdriving pixel circuits of the display to correspond to the driving of a periodically varying light, and modulating the light using the pixel circuits
Data Source
AI summary
A method of operating a display includes providing light having a luminance that varies periodically, overdriving a pixel circuit of the display, and modulating the light using the pixel circuit to generate modulated light. The amount of overdrive and the phase of the light relative to the overdriving of the pixel circuit are controlled such that the modulated light has a predetermined level of uniformity.