Edge-Type Backlight Unit With Grooved Light Guide Plate
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Solution Overview
Problem
Liquid crystal display (LCD) devices face image quality issues due to lamp mura defects caused by insufficient distance between lamps and diffuser plates in backlight units, leading to non-uniform light distribution and reduced image quality.
Innovation Solution
An edge-type backlight unit with a light guide plate featuring grooves that divide the surface into areas, each driven by separate LED packages, allowing for a scanning block-division driving method where LEDs are turned on and off sectionally to provide light to specific areas, preventing light overlap and enhancing contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance between lamps and diffuser plate is reduced to provide thin LCD device, then device thickness is reduced, but lamp mura defects occur and image quality is lowered
Solution Approach 1:
The light guide plate is divided into multiple independent light guide regions separated by black matrix regions. Each light guide region receives light from dedicated LED packages, preventing light overlap and ensuring uniform light distribution even at reduced distances, thereby eliminating lamp mura defects while maintaining thin device profile
Solution Approach 2:
Different regions of the light guide plate are independently controlled through separate LED packages and black matrix regions. This local quality approach allows each region to be optimized independently, preventing light interference between adjacent areas and maintaining high image quality in the thin device structure
2Length of moving object
If lamps are disposed close to diffuser plate to reduce device thickness, then device thickness is reduced, but light distribution becomes non-uniform causing lamp mura defects
Solution Approach 1:
The light guide plate is segmented into multiple independent light guide regions by black matrix regions. Each region is illuminated by dedicated LED packages, ensuring that light from one region does not overlap with adjacent regions. This segmentation maintains uniform light distribution even when the distance between light sources and light guide plate is minimized
Solution Approach 2:
Black matrix regions serve as intermediaries that optically isolate adjacent light guide regions. These black matrix regions prevent light from one LED package from entering adjacent light guide regions, thereby maintaining uniform light distribution and preventing lamp mura defects in thin device configurations
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 improves image contrast and vividness by adjusting brightness levels and reducing power consumption, while preventing lamp mura defects and ensuring uniform brightness across the LCD panel.
Implementation Method 1
a first LED assembly disposed at a first side surface of the light guide plate, the first LED assembly including (n+1) LED packages
Implementation Method 2
a light guide plate over the reflection plate, the light guide plate having n grooves at a lower surface
Implementation Method 3
the light guide plate having n grooves at a lower surface and including (n+1) areas divided by the grooves
Implementation Method 4
a plurality of optical sheets over the light guide plate
Data Source
AI summary
A backlight unit for a liquid crystal display device includes a reflection plate, a light guide plate over the reflection plate, the light guide plate having n grooves at a lower surface and including (n+1) areas divided by the grooves, wherein n is a natural number, a first LED assembly disposed at a first side surface of the light guide plate, the first LED assembly including (n+1) LED packages, each of which has at least one LED, wherein the LED packages of the first LED assembly correspond to the areas, respectively, and are separately driven, and a plurality of optical sheets over the light guide plate.