Liquid Crystal Display Backlight Modulation for Motion Clarity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid crystal display technologies face challenges in improving motion picture response time (MPRT) performance due to light interference from differing turn-on and turn-off times of light sources and limitations in controlling light incident on the panel, especially in edge type backlight units, which result in reduced luminance and uneven performance across the screen.
Innovation Solution
A liquid crystal display system that includes a light source control circuit to modulate the turn-on and turn-off operations of light sources, using pulse width modulation (PWM) and current control signals, and divides the frame period into sub-frames to synchronize data and gate driving with a higher frequency, allowing for uniform light distribution and reduced turn-on time differences across the panel, thereby improving MPRT performance without reducing luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light sources are turned off for a predetermined time in each frame period to improve MPRT performance, then motion blur is reduced, but the screen becomes dark
Solution Approach 1:
The patent applies periodic action by sequentially turning on and off multiple light sources in a time-division manner within each frame period. Instead of turning off all light sources simultaneously, the system divides them into groups that are activated at different time intervals, creating a periodic scanning pattern that maintains continuous illumination while improving motion response
Solution Approach 2:
The patent segments the backlight unit into multiple independently controllable light source groups. Each group can be turned on and off separately, allowing the system to activate only the necessary portion of light sources at any given time, thereby reducing overall power consumption and heat generation while maintaining required brightness levels
2Reliability
If turn-on times or turn-off times of light sources are different in scanning blocks to achieve scanning backlight driving, then MPRT performance is improved, but light interference occurs in boundary portions
Solution Approach 1:
The patent applies local quality by implementing different timing control strategies for different spatial regions. Light sources in boundary portions are controlled with adjusted turn-on and turn-off times compared to central regions, creating location-specific illumination patterns that eliminate light interference at boundaries while maintaining the scanning effect in the overall display area
3Ease of manufacture
If light sources are positioned in edge type backlight unit to reduce device complexity, then manufacturing is easier, but it is difficult to control light incident on the liquid crystal display panel in each scanning block
Solution Approach 1:
The patent applies dynamics by implementing dynamic control of light source activation based on real-time scanning requirements. The system dynamically adjusts which edge-positioned light sources are turned on at specific time intervals, enabling precise spatial and temporal control of light incident on different scanning blocks despite the fixed edge-type physical configuration
Data Source
AI summary
A liquid crystal display includes a liquid crystal display panel, a data driving circuit, a gate driving circuit, a plurality of light sources, a light source control circuit configured to differently modulate a unit frame data depending on a display location of the unit frame data on the liquid crystal display panel and to control turn-on and turn-off operations of the light sources, a timing controller configured to divide a unit frame period into first and second sub-frame periods and to repeatedly supply the modulated unit frame data to the data driving circuit during the first and second sub-frame periods, and a light source driving circuit configured to turn off all the light sources during the first sub-frame period and turn on all the light sources at a turn-on time within the second sub-frame period.