LCD Backlight Current Control for Smooth HDR Local Dimming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional local dimming methods in HDR displays cause sudden brightness changes during frequent picture switching, affecting user experience and inefficiently utilize power supply capabilities.
Innovation Solution
A display brightness adjustment method that automatically and continuously adjusts display brightness using a current between a maximum and minimum current provided by the power supply, ensuring local peak brightness and smooth gradation of dynamic pictures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional local dimming method with two levels of currents is used, then power consumption is controlled within supply capability, but sudden brightness change occurs during frequent picture switching
Solution Approach 1:
The patent applies dynamics by transitioning from a static two-level current system to a dynamic multi-level current system. The backlight source current is dynamically adjusted across multiple levels (first level, second level, third level) based on real-time APL values and picture switching detection, enabling smooth brightness transitions without sudden changes that affect user experience.
Solution Approach 2:
The patent changes the parameter of current level from discrete two-level control to continuous multi-level control. By introducing intermediate current levels between minimum and maximum, the system achieves gradual brightness adjustment rather than abrupt transitions, resolving the contradiction between power control and brightness stability.
2Use of energy by moving object
If a conventional local dimming method with two levels of currents is used, then power consumption is controlled within supply capability, but brightness gradation becomes rough
Solution Approach 1:
The patent segments the current control range into multiple discrete levels (first current level, second current level, third current level) between the minimum and maximum currents. This segmentation allows the system to maintain power consumption within supply capability while achieving smoother brightness gradation through intermediate steps, rather than relying on only two broad current levels.
Solution Approach 2:
The system dynamically selects appropriate current levels based on APL values and picture switching states, transitioning smoothly between multiple current levels to achieve fine-grained brightness control that maximizes power supply utilization while maintaining smooth gradation.
3Illumination intensity
If maximum current is used to drive backlight source, then local peak brightness is ensured, but power consumption exceeds supply capability
Solution Approach 1:
The patent applies local quality by using maximum current only when and where needed (low APL scenarios requiring high brightness), while using lower current levels (second level, third level) during other conditions. This selective application of maximum current ensures local peak brightness is achieved only when necessary, optimizing power consumption while maintaining display quality.
4Use of energy by moving object
If minimum current is used to drive backlight source, then power consumption is reduced, but local peak brightness capability is insufficient
Solution Approach 1:
The system dynamically adjusts current levels based on actual display needs. Instead of operating at minimum current continuously, the system transitions to higher current levels (second level, third level) when brightness capability is required, achieving an optimal balance between power consumption and local peak brightness capability through adaptive current 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
Maximizes power supply capability for the display panel while maintaining both local peak brightness and smooth gradation of brightness in HDR displays.
Implementation Method 1
A liquid crystal display (liquid crystal display, LCD) is a passive light emitting body, and emits light by a light emitting diode backlight source on the back
Implementation Method 2
The LCD may include a direct lit backlight LCD and an edge lit backlight LCD
Data Source
Figure 1
Figure 2~3A
Figure 3B~4A
AI summary
This application discloses a display brightness adjustment method. The method includes: An electronic apparatus obtains a to-be-displayed image. The electronic apparatus determines an average pixel brightness value of each backlight partition on a liquid crystal display panel based on the to-be-displayed image. A backlight region of the liquid crystal display panel is divided into a plurality of backlight partitions. The electronic apparatus determines an initial dimming duty cycle corresponding to each backlight partition based on the average pixel brightness value of each backlight partition. The electronic apparatus determines a drive current value based on the initial dimming duty cycle corresponding to each backlight partition and drive current threshold data. The electronic apparatus adjusts, based on the drive current value, light emitting brightness of the backlight region that exists when the to-be-displayed image is displayed. In this way, display brightness of a displayed image can be automatically and continuously adjusted based on content of the displayed image.