Backlight Reflecting Sheet Dot Patterns for Brightness Uniformity
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Solution Overview
Problem
Conventional backlight units for liquid crystal display panels face challenges in achieving uniform light distribution and reducing non-uniformity of brightness, particularly due to the inefficiencies in reflecting light emitted from the sides of light sources.
Innovation Solution
A backlight unit design incorporating a reflecting sheet with a specific pattern of dots and holes, where the reflecting sheet includes a first sheet part with holes and dots, and a second sheet part extended from the first sheet, with the dots positioned adjacent to the holes, and a third sheet part with support plate holes, to optimize light reflection and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional reflecting sheet is used without dot patterns, then the structure is simple and easy to manufacture, but the light distribution is non-uniform and brightness varies across the display panel
Solution Approach 1:
The reflecting sheet incorporates dot patterns at specific locations (adjacent to light sources and at corners) with different reflectance characteristics. These localized dot areas modify light reflection in specific regions to compensate for non-uniform light distribution, achieving overall uniformity without requiring complete structural complexity throughout the entire sheet.
Solution Approach 2:
The reflecting sheet is divided into functional zones: dot areas positioned adjacent to light sources, corner dot areas, and non-dot areas. This segmentation allows each zone to perform its specific function in controlling light reflection, thereby achieving uniform light distribution while maintaining manufacturing feasibility through modular design.
2Illumination intensity
If the reflecting sheet covers the entire area, then light reflection is maximized, but light emitted from sides of light sources creates non-uniform brightness
Solution Approach 1:
Dot areas are strategically positioned adjacent to light sources where side-emitted light occurs. These dot areas have reduced reflectance or different optical properties to specifically address the non-uniform brightness caused by side light emission, while other areas maintain normal reflection characteristics to preserve overall light efficiency.
Solution Approach 2:
The patent converts the harmful effect of side-emitted light (which causes non-uniform brightness) into a beneficial feature by positioning dot areas to specifically manage this light. The side-emitted light that would normally create brightness non-uniformity is redirected or absorbed by the dot areas, transforming the problem into a controlled light distribution mechanism.
3Manufacturing precision
If dot areas are added to control light reflection, then brightness uniformity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Instead of requiring complete coverage or complex patterns throughout the reflecting sheet, the invention uses localized dot areas at critical positions (adjacent to light sources and corners). This approach achieves brightness uniformity through minimal, strategically placed features that are easier to manufacture using standard printing or deposition techniques.
Solution Approach 2:
The patent applies dot patterns partially only where needed (adjacent to light sources and at corners) rather than uniformly across the entire reflecting sheet. This partial action is sufficient to achieve the desired brightness uniformity while significantly simplifying the manufacturing process compared to full-coverage solutions.
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 design enhances uniform light reflection and reduces non-uniformity of brightness across the display panel, providing a more consistent viewing experience by controlling the reflectance of light emitted from the light sources.
Implementation Method 1
a reflecting sheet located on the at least one substrate, wherein the reflecting sheet includes a first sheet part located on the bottom, the first sheet part including a plurality of holes corresponding to the plurality of light sources, and a plurality of first dots
Data Source
AI summary
A display device includes a display panel; a light source; a frame at a rear of the display panel; and a reflecting sheet between the display panel and the frame, the reflecting sheet having a rectangular shape with a first long side, a second long side opposite the first long side, a first short side adjacent to the first long side and the second long side, and a second short side opposite the first short side. Further, the reflecting sheet includes a first horizontal area along the first long side, and a first vertical area along the first short side. In addition, at least one of the first horizontal area and the first vertical area includes a first area including a plurality of first dots, a second area including a plurality of second dots and a third area including a plurality of third dots.