Backlight Unit Diffusion Plate Edge Thickness Design
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Solution Overview
Problem
In thin-profile liquid crystal display (LCD) devices, the reduced thickness of the backlight unit leads to insufficient light diffusion at the edges, causing dark portions and reduced brightness uniformity.
Innovation Solution
A backlight unit with a diffusion plate that includes a first region along the edges with a decreasing thickness or through-holes of increasing density towards the outer side, enhancing transmittance and preventing dark portions by improving light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the backlight unit is reduced to achieve a thin-profile LCD device, then the overall device thickness is reduced, but the optical gap is reduced and light diffusion at edge portions becomes insufficient
Solution Approach 1:
The diffusion plate is designed with a first region at the edges having different optical properties (decreasing thickness or increasing through-hole density) compared to the second region at the center. This local differentiation enables enhanced light diffusion specifically at the edge portions where darkness occurs, while maintaining the overall thin-profile structure of the backlight unit.
Solution Approach 2:
Instead of increasing the overall thickness of the diffusion plate or backlight unit, the invention introduces structural variations in the thickness dimension of the diffusion plate itself. The first region has a smaller thickness than the second region, creating a three-dimensional structural variation that enhances light diffusion at edges without increasing the overall device thickness.
2Illumination intensity
If the thickness of the diffusion plate is uniformly increased to improve light diffusion, then brightness uniformity improves, but the overall device thickness increases
Solution Approach 1:
Rather than uniformly increasing the diffusion plate thickness, the invention applies local thickness variation where only the first region at the edges has reduced thickness to enhance light diffusion. The second region at the center maintains its original thickness, thus achieving improved brightness uniformity without increasing the overall diffusion plate thickness.
Solution Approach 2:
The diffusion plate is segmented into two distinct regions: a first region at the edges with reduced thickness or increased through-hole density, and a second region at the center with original thickness. This segmentation allows each region to perform its specific function - the first region addresses edge darkness while the second region maintains overall light diffusion.
3Illumination intensity
If more LED packages or higher driving current are used to compensate for edge darkness, then brightness uniformity improves, but power consumption increases
Solution Approach 1:
The diffusion plate structure itself performs the function of compensating for edge darkness through its geometric design (variable thickness or through-hole distribution). The optical structure passively redirects and diffuses light to the edge portions without requiring additional energy input, thus maintaining brightness uniformity without increasing power consumption.
Solution Approach 2:
The diffusion plate acts as an intermediary optical element between the LED light sources and the liquid crystal panel. By designing the diffusion plate with specific geometric features (variable thickness or through-hole patterns), it mediates the light distribution to achieve uniform brightness without requiring changes to the LED packages or driving current.
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 effectively prevents dark portions at the edges and achieves uniform brightness without the need for increased LED packages or driving current, reducing power consumption and maintaining a thin profile.
Implementation Method 1
a plurality of light sources are arranged directly below the liquid crystal panel and thus supply a light to the liquid crystal panel
Implementation Method 2
a reflective pattern sheet located on the encapsulation layer and the diffusion plate, and including a plurality of reflective patterns respectively corresponding to the plurality of LED packages
Implementation Method 3
a fluorescent sheet between the diffusion plate and the optical sheet or between the diffusion plate and the reflective pattern sheet
Data Source
AI summary
A backlight unit includes a diffusion plate, wherein the diffusion plate includes a first region along edges of the diffusion plate, and a second region surrounded by the first region, and wherein a thickness of the first region decreases toward an outer side direction of the diffusion plate.