Liquid Crystal Display Backlight Light Guide Channels Local Dimming
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Solution Overview
Problem
Existing liquid crystal displays face challenges in achieving high contrast and slim design due to limitations in implementing local dimming methods, particularly with edge type backlight units which struggle to diffuse light evenly, leading to issues with luminance evenness and increased thickness in direct type units.
Innovation Solution
A liquid crystal display with a backlight unit featuring a light guide plate with formed light guide channels and multiple light sources, a division driving controller that analyzes and independently modulates luminance for each block, and a light source driver that adjusts light source intensity based on dimming values, allowing for local dimming and improved contrast while maintaining slimness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a direct type backlight unit with multiple light sources is used to implement local dimming, then contrast property is improved, but device thickness increases
Solution Approach 1:
The backlight unit is divided into multiple independently controllable light sources arranged in a matrix pattern, allowing separate control of different regions. This segmentation enables local dimming by adjusting specific light sources based on picture content, improving contrast without requiring the entire backlight to be thick
Solution Approach 2:
Different regions of the display are provided with different luminance levels by independently controlling individual light sources or groups of light sources. The division driving controller analyzes picture luminance and applies local dimming values to specific light sources, creating local quality variations that enhance contrast while maintaining overall thinness
2Length of stationary object
If the space between light sources and diffusion plate is reduced to achieve slim design, then device thickness is reduced, but luminance evenness deteriorates due to bright lines
Solution Approach 1:
Instead of using a single large diffusion plate requiring large spacing, the system divides the backlight into multiple smaller light sources. This segmentation allows sufficient light diffusion from each individual source while maintaining reduced overall spacing, preventing bright lines while achieving slim design
Solution Approach 2:
The system dynamically adjusts the luminance of individual light sources based on picture content analysis. The division driving controller modulates each light source's output to compensate for potential luminance unevenness, adapting in real-time to maintain even display quality while keeping the structure thin
3Illumination intensity
If the number of light sources is increased to improve luminance evenness, then luminance evenness is improved, but device complexity and cost increase
Solution Approach 1:
Rather than uniformly increasing the number of light sources across the entire display, the system implements local dimming with a moderate number of light sources strategically positioned. The division driving controller achieves improved luminance evenness by selectively modulating specific light sources based on picture content, rather than requiring excessive light sources everywhere
Solution Approach 2:
The division driving controller acts as an intermediary that analyzes picture luminance and translates it into appropriate dimming values for each light source. This intelligent control mechanism compensates for the limited number of light sources, achieving good luminance evenness without requiring a complex array of numerous light sources
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 contrast properties and achieves a slim design by effectively dividing and controlling light within the liquid crystal display, improving luminance evenness and reducing power consumption through independent modulation of light sources.
Implementation Method 1
a light guide plate part in which a plurality of light guide channels are formed, and a plurality of light sources for illuminating light to the light guide channels
Data Source
AI summary
A liquid crystal display and a driving method thereof capable of improving contrast properties by implementing a local dimming and achieving the slimness of the liquid crystal display. The liquid crystal display comprises a liquid crystal display panel, a backlight unit including a light guide plate part in which a plurality of light guide channels are formed, and a plurality of light sources for illuminating light to the light guide channels, a division driving controller for mapping an input picture to a plurality of blocks in which a plurality of data channels are intersected with the plurality of light guide channels, analyzing luminance of the input picture for each block, determining dimming values of the plurality of light sources, and independently modulating the luminance of the input picture for each block based on the analyzed result, and a light source driver for independently controlling luminance of the light sources responding to the dimming values.