Field Sequential Color LCD Timing Control for Luminance Uniformity
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Solution Overview
Problem
The field sequential color driving method for liquid crystal displays (LCDs) faces challenges in maintaining picture quality and contrast ratio at low temperatures due to limited design margins in addressing and flash periods, leading to luminance deviations and increased power consumption, especially when frame frequency increases.
Innovation Solution
A liquid crystal display system that dynamically adjusts the horizontal period, wait period, and flash period based on user-set signals and ambient conditions, allowing for variable sub-field times to optimize the timing chart and reduce luminance deviations, while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frame frequency is increased to improve refresh rate, then productivity is improved, but the wait period becomes insufficient causing luminance deviation and picture quality degradation
Solution Approach 1:
The patent applies dynamics by making the horizontal period variable rather than fixed. The timing controller dynamically adjusts the horizontal period length based on frame frequency requirements, allowing the display system to adapt to different operating conditions. This resolves the contradiction by enabling high frame frequencies while maintaining sufficient wait periods through extended horizontal periods.
Solution Approach 2:
The patent changes the parameter of horizontal period from a fixed value to a variable parameter that can be adjusted according to frame frequency. By modifying this timing parameter, the system can accommodate higher frame frequencies while preserving adequate wait periods, thus maintaining luminance uniformity and picture quality even at increased productivity levels.
2Manufacturing precision
If the wait period is extended to improve luminance uniformity, then picture quality is improved, but the flash period decreases reducing brightness
Solution Approach 1:
The patent uses dynamics to allow flexible adjustment of both wait period and flash period durations. Rather than having a fixed trade-off, the system can dynamically optimize the distribution of time within the horizontal period based on ambient temperature and display conditions, achieving both luminance uniformity and adequate brightness.
Solution Approach 2:
The patent changes the timing parameters from fixed values to adjustable parameters. The timing controller can modify the lengths of wait period and flash period independently based on environmental conditions, allowing optimization of both luminance uniformity and brightness simultaneously rather than forcing a trade-off between them.
3Illumination intensity
If the flash period is extended to improve brightness, then illumination intensity is improved, but the wait period decreases causing luminance deviation
Solution Approach 1:
The patent applies dynamics by enabling the timing controller to adjust flash period and wait period durations based on real-time conditions. This dynamic adjustment capability allows the system to extend flash period for brightness when needed while compensating by extending the overall horizontal period to maintain sufficient wait period, thus avoiding luminance deviation.
Solution Approach 2:
The patent modifies the timing parameters from fixed to variable, allowing the system to optimize the relationship between flash period and wait period. By changing these parameters dynamically, the system can achieve both extended flash period for brightness and sufficient wait period for luminance uniformity simultaneously.
4Device complexity
If fixed timing parameters are used to simplify control, then device complexity is reduced, but picture quality degrades at low temperature due to insufficient design margin
Solution Approach 1:
The patent applies dynamics by implementing a timing controller that automatically adjusts horizontal period, wait period, and flash period based on ambient temperature and display conditions. This dynamic control mechanism maintains picture quality at low temperatures by extending timing parameters when needed, while keeping the control system integrated and manageable rather than overly complex.
Solution Approach 2:
The patent uses feedback by having the timing controller monitor ambient temperature and display conditions, then automatically adjust timing parameters accordingly. This feedback mechanism ensures picture quality is maintained at low temperatures without requiring manual intervention or overly complex control circuits, resolving the contradiction between simplicity and reliability.
Data Source
AI summary
Disclosed are a liquid crystal display, which can increase a design margin upon designing a driving timing chart, improve picture quality characteristics and reduce power consumption, and a method for driving the same. The liquid crystal display of a field sequential color type comprises an LCD panel having a plurality of pixels arranged in a matrix form defined by gate lines and data lines crossing each other, a sub-field time setting unit for selecting 1 horizontal period according to an externally input frame frequency and a first user-set signal and determining a wait period and a flash period corresponding to the 1 horizontal period according to second and third user-set signals, a timing controller for producing and outputting a gate control signal and a data control signal corresponding to the 1 horizontal period and the wait period and a light source control signal corresponding to the wait period and a re-aligned pixel data, a gate driver for sequentially outputting a scan pulse to the gate lines according to the gate control signal, a data driver for outputting a data voltage to the data lines every 1 horizontal period according to the data control signal, and a backlight unit for sequentially outputting red, green and blue light to the pixels, respectively, according to the control of the timing controller.