On-Chip Frame Buffer Overdrive for LCD Response Time
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Solution Overview
Problem
Liquid Crystal Displays (LCDs) often experience slow response times, leading to digital noise and ghosting due to their inability to keep up with information transmission, resulting in undesirable screen artifacts when response time exceeds the refresh period.
Innovation Solution
An electronic device with signal adjusting circuitry that determines if a target pixel intensity is difficult to achieve within a frame refresh period, adjusts the signal, and overdrives the pixel using a lookup table to achieve the desired intensity level, thereby reducing artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LCD refresh period is kept standard, then power consumption and complexity are maintained, but response time becomes insufficient leading to digital noise and ghosting artifacts
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and storing overdrive levels in a lookup table that compensates for expected response time deficiencies. The signal adjusting circuitry proactively adjusts pixel intensity signals before they reach the LCD, preventing the occurrence of digital noise and ghosting artifacts rather than correcting them after they appear.
Solution Approach 2:
The patent changes the signal parameter (pixel intensity level) dynamically based on the current frame and previous frame data. By modifying the voltage signal parameters sent to pixels, the system accelerates liquid crystal response time without changing the physical LCD structure or refresh period, thereby resolving the contradiction between response time and display quality.
2Loss of time
If overdriving is applied to accelerate pixel transitions, then response time improves, but signal complexity and processing requirements increase
Solution Approach 1:
The patent uses a lookup table that stores pre-calculated overdrive level data, effectively copying proven signal adjustment patterns rather than calculating them in real-time. This approach simplifies the processing complexity while maintaining the response time benefits of overdriving, as the circuitry only needs to retrieve and apply stored values based on current and previous frame pixel intensities.
3Speed
If signal adjustment circuitry is added to overdrive pixels, then pixel transition speed increases, but device complexity and manufacturing cost increase
Solution Approach 1:
The signal adjusting circuitry is designed to be integrated into the existing LCD driver architecture, allowing the same hardware components to serve multiple functions: normal pixel driving, overdrive signal generation, and artifact reduction. This multi-functionality approach accelerates pixel transitions while minimizing the addition of separate dedicated circuitry, thereby controlling manufacturing complexity.
Data Source
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AI summary
Method and system is disclosed for improving the response time of displays 24, such as liquid crystal displays (LCDs). The method includes receiving a target picture frame and comparing it to a current picture frame. If the comparison shows that a display 24 may be unable to transition from a current pixel intensity level to a target pixel intensity level within a specified time period, then the pixels that correspond to those current pixel intensities that may not be reach target pixel intensities may be overdriven. This overdriving of one or more pixels may allow the pixel to reach the target pixel intensity within the specified time period.