Edge-Type Backlight With Intersecting Light Guide Channels
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Solution Overview
Problem
Liquid crystal displays face challenges in achieving high contrast and slimness due to limitations in implementing local dimming methods, which result in distortion and decreased luminance, particularly with edge type backlight units where light source orientation causes uneven luminance and bright lines on the screen.
Innovation Solution
A liquid crystal display design featuring a light guide plate with intersecting first and second light guide channels, each illuminated by separate light arrays, and a dimming controller that analyzes input pictures to adjust luminance independently for each block, reducing luminance differences between neighboring blocks and compensating for distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming method is applied to direct type backlight unit, then contrast property is improved, but thickness increases due to space between light sources and diffusion plate
Solution Approach 1:
The patent transitions from direct type backlight (light sources facing diffusion plate) to edge type backlight (light sources arranged at edges), changing the spatial dimension of light source arrangement. This allows local dimming to be implemented while reducing overall thickness by eliminating the need for space between light sources and diffusion plate.
Solution Approach 2:
The patent divides the backlight unit into multiple independently controllable light sources arranged at edges, allowing separate control of different regions. This segmentation enables local dimming functionality while maintaining a thinner profile through edge-type configuration.
2Length of stationary object
If local dimming method is applied to edge type backlight unit, then thickness is reduced, but distortion and luminance decrease occur due to light guide plate light distribution characteristics
Solution Approach 1:
The patent applies different dimming values to different blocks corresponding to different regions of the light guide plate. By analyzing picture content for each block and applying localized luminance compensation, it corrects the uneven luminance distribution caused by edge-type light guide plate characteristics while maintaining thinness.
Solution Approach 2:
The patent implements a feedback mechanism where the controller analyzes the input picture, determines appropriate dimming values for each block, and adjusts light source luminance accordingly. This feedback loop compensates for distortion and luminance unevenness by adapting to the actual display requirements of different regions.
3Use of energy by stationary object
If global dimming method is used, then power consumption is reduced by adjusting overall luminance, but static contrast improvement is limited compared to local dimming
Solution Approach 1:
The patent divides the display area into multiple blocks that can be independently controlled. By applying local dimming to specific blocks rather than uniformly adjusting all light sources, it achieves both power savings (by dimming only necessary regions) and improved static contrast (by maintaining brightness in other regions), resolving the trade-off between global dimming's power efficiency and local contrast 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
This approach enhances contrast properties, achieves slimness, and effectively compensates for distortion and luminance decreases, improving overall display quality while reducing power consumption compared to global dimming methods.
Implementation Method 1
a light guide plate part in which first light guide channels of a first direction and second light guide channels of a second direction intersected with the first direction are formed
Data Source
AI summary
A liquid crystal display and a method of driving the same capable of improving contrast properties by implementing a local dimming method and achieving the slimness of the liquid crystal display are provided. The liquid crystal display includes a liquid crystal display panel which displays a picture; a backlight unit including a light guide plate part in which first light guide channels of a first direction and second light guide channels of a second direction intersected with the first direction are formed, first light array for illuminating light to the first light guide channels, and second light array for illuminating light to the second light guide channels, respectively, wherein blocks are defined by the intersection of the first light guide channels and second light guide channels; and a dimming controller for analyzing an input picture to correspond to the blocks to obtain first dimming values for independently controlling luminances of light sources of the first light array, determining second dimming values for independently controlling luminances of light sources of the second light array based on the first dimming values, and adjusting the first and second dimming values so that a luminance difference between neighboring blocks caused by the first and second dimming values is decreased.