Back Light Unit With Segmented Diffusing Plate For Uniformity
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Solution Overview
Problem
Existing back light units for liquid crystal display devices face challenges in achieving uniform light distribution and thickness, particularly with edge-lighting types which have low luminance and are difficult to apply to large-sized displays, and direct-lighting types which require additional space for uniform distribution, limiting the fabrication of thinner devices.
Innovation Solution
A back light unit design featuring a bottom cover with multiple light source modules, each comprising a PCB with LED light sources, a diffusing plate spaced from the LEDs, and a diffusing plate supporter, where the diffusing plate includes a flat portion and side walls with light diffusing units projected towards the LEDs, optimizing the shape and position of these units for improved light distribution and reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a diffusing plate is placed close to LED light sources, then the back light unit thickness is reduced, but uniform light distribution is compromised
Solution Approach 1:
The diffusing plate is segmented into multiple functional regions: a first diffusing region closer to the LED for initial light scattering, and a second diffusing region farther from the LED for additional uniformization. This segmentation allows the plate to achieve both thinness and uniformity by distributing the diffusing function across different zones rather than requiring uniform spacing throughout.
Solution Approach 2:
Different regions of the diffusing plate are designed with different optical properties and spacing from the LED. The first diffusing region has different characteristics than the second diffusing region, allowing each zone to optimize light distribution locally while contributing to the overall uniformity and thinness of the back light unit.
2Illumination intensity
If additional space is provided for uniform light distribution, then light uniformity is improved, but device thickness increases
Solution Approach 1:
The diffusing plate is divided into multiple diffusing regions at different distances from the LED, allowing the system to achieve uniform light distribution without requiring excessive overall thickness. Each region contributes to uniformity while maintaining compact spacing.
Solution Approach 2:
Instead of increasing thickness uniformly across the entire back light unit, the invention utilizes vertical positioning of different diffusing regions at different heights from the LED. This dimensional arrangement allows for uniform light distribution in a compact thickness by optimizing the vertical dimension rather than requiring uniform expansion in all directions.
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 design enables the fabrication of thinner liquid crystal display devices with improved light uniformity and luminance, minimizing unnecessary light loss and allowing for more flexible design of liquid crystal display devices with enhanced mechanical reliability and cost-effectiveness.
Implementation Method 1
a diffusing plate spaced a distance from the LED light sources and surrounding the PCB fully for diffusing a light incident thereon from the LED light sources throughout a surface thereof uniformly
Implementation Method 2
a plurality of light diffusing units each projected from a surface facing the LED light source on the plate portion at a position matched to the LED light source
Data Source
AI summary
A back light unit includes a bottom cover, a plurality of light source modules mounted on the bottom cover, and an optical sheet unit over the light source modules, wherein each of the light source module includes a PCB having the plurality of light source modules mounted thereon, a diffusing plate spaced a distance from the LED light sources and surrounding the PCB fully for diffusing a light incident thereon from the LED light sources throughout a surface thereof uniformly, and a diffusing plate supporter for securing the diffusing plate to the PCB, and the diffusing plate includes a flat plate portion, a side wall portion extended from opposite edges of the plate portion to the diffusing plate supporter, and a plurality of light diffusing units each projected from a surface facing the LED light source on the plate portion at a position matched to the LED light source, thereby enabling to make effective response to fabrication of thinner liquid crystal display device and improve a light uniformity, and improve light utilization efficiency to improve a luminance, and enhance mechanical reliability.