Local Dimming Backlight Control for LCD Power and Luminance
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Solution Overview
Problem
Conventional liquid crystal display (LCD) devices with constant backlight luminance struggle to dynamically express high-luminance images, such as explosion or flashlight scenes, leading to increased power consumption and difficulty in animating images effectively.
Innovation Solution
An image display device with a liquid crystal display panel divided into blocks, a system main body that generates block dimming data by analyzing image data, and a backlight unit driven by block dimming voltages to control light transmittance, allowing for improved partial luminance and reduced power consumption through local dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If constant luminance is maintained in the backlight unit, then power consumption increases, but image animation capability is limited
Solution Approach 1:
The backlight unit is divided into multiple independently controllable backlight blocks corresponding to display blocks on the liquid crystal display panel. Each backlight block can be controlled separately to emit light with different luminance levels, enabling localized luminance adjustment without affecting the entire display area. This segmentation allows the system to reduce power consumption by dimming or turning off specific backlight blocks when their corresponding display regions require lower luminance, while maintaining high luminance capability in other regions when needed for animated image expression.
Solution Approach 2:
The backlight unit transitions from a static constant luminance state to a dynamic state where luminance can be adjusted in real-time based on image content. The control system analyzes display image data and dynamically adjusts the luminance of each backlight block accordingly, enabling the backlight to adapt to different scene requirements (such as explosion scenes or flashlight scenes) and thereby improving image animation capability while optimizing power consumption.
2Illumination intensity
If constant luminance is applied to the liquid crystal display panel, then partial luminance improvement is difficult, but power consumption increases
Solution Approach 1:
Different luminance levels are applied to different spatial regions (backlight blocks) based on the local requirements of the display image. The control system analyzes the image content and assigns appropriate luminance levels to each backlight block, allowing high luminance in regions requiring detailed visibility and low luminance in regions where lower brightness suffices. This local quality approach improves partial luminance in specific areas without requiring the entire backlight unit to operate at high power consumption levels.
3Illumination intensity
If the liquid crystal display panel is directly illuminated by plural lamps, then high luminance is realized, but power consumption increases
Solution Approach 1:
The backlight unit comprising plural lamps is segmented into multiple backlight blocks, each corresponding to a display block on the liquid crystal display panel. This segmentation enables independent control of each lamp or lamp group within a backlight block, allowing the system to activate only the necessary lamps for displaying current image content. High luminance is maintained in regions requiring it, while power consumption is reduced by keeping other lamps off or at low power states.
Solution Approach 2:
Instead of activating all lamps at full power continuously, the system applies partial action by activating only the necessary portion of lamps required for the current display scene. The control system determines the minimum necessary luminance for each display block and activates相应 backlight blocks accordingly, avoiding excessive power consumption while maintaining sufficient luminance for image quality.
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
The solution enhances image display by dynamically adjusting luminance in specific areas, reducing power consumption and enabling more efficient image rendering with various analysis algorithms, while minimizing manufacturing costs.
Implementation Method 1
a backlight unit for emitting light to the plural display blocks
Implementation Method 2
a liquid crystal display panel with plural display blocks; wherein a transmittance of light emitted from the backlight unit is controlled in the liquid crystal display panel
Data Source
AI summary
Disclosed is an image display device and its driving method, which facilitates to improve partial luminance in an image-display area by a local dimming method to partially control a backlight unit according to a display image, and simultaneously to reduce power consumption.