Dynamic Image Over-driving for LCD Overshoot Mitigation
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Solution Overview
Problem
Conventional image over-driving methods for LCDs suffer from an overshot effect when displaying objects with low gray levels or high speed, degrading image quality due to the limited response time of liquid crystal display units.
Innovation Solution
An image over-driving device and method that dynamically detect the size and moving speed of displayed objects, using a multiplexer and lookup tables to generate and select over-driving signals that adjust the cross voltage, thereby mitigating the overshot effect by employing lower over-driving voltages when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional over-driving method is used to accelerate gray-level change, then response speed of liquid crystal display unit is improved, but image quality is degraded due to overshot effect
Solution Approach 1:
The patent dynamically changes over-driving parameters (voltage magnitude, duration) based on detected object characteristics. When a small or fast-moving object is detected, the system adjusts the over-driving voltage to be lower or shorter in duration, preventing overshot effect while still accelerating the gray-level transition. This resolves the contradiction by making the over-driving parameters adaptive rather than fixed.
Solution Approach 2:
The patent implements a feedback mechanism where the system detects object size and moving speed, then uses this information to control the over-driving voltage application. The detection unit provides feedback about the displayed object characteristics, and the control unit adjusts the over-driving parameters accordingly. This closed-loop control prevents overshot effect while maintaining fast response speed.
2Loss of time
If over-driving voltage is increased to enhance efficacy of gray-level change, then response time is reduced, but overshot effect occurs degrading image quality
Solution Approach 1:
The patent makes the over-driving voltage dynamic rather than static. The system continuously monitors object characteristics (size, speed) and adjusts the over-driving voltage in real-time. For small or fast-moving objects, the over-driving voltage is reduced or applied for shorter duration, preventing overshot effect. For larger or stationary objects, full over-driving voltage can be applied to maximize response speed improvement.
Data Source
AI summary
An image over-driving device is provided. An image detection device detects a size and a moving speed of an object according to an image signal and outputs an over-driving control signal according to the detected size and moving speed. A first image register receives and temporarily stores first image data of the image signal in a first frame period, and receives second image data of the image signal and outputs the first image data as a buffer data in a sequential second frame period. A first over-driving unit includes first and second lookup tables recording different over-driving parameters. The first over-driving unit generates first and second over-driving signals according to the buffer data and the second image data respectively by using the first and second lookup tables. The first multiplexer selects the first or second over-driving signal according to the over-driving control signal to drive a display device.