Backlight Assembly Semi-Ellipsoidal Lens Hot Spot Reduction
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Solution Overview
Problem
Conventional LED lamps for liquid crystal displays (LCDs) suffer from hot spots due to non-uniform light distribution, where regions close to LED packages receive more light than areas between them, leading to bright and dark areas in the backlight.
Innovation Solution
A backlight assembly featuring a substrate with LED packages and a lens unit comprising semi-ellipsoidal lenses that partially overlap to diffuse light more evenly, reducing hot spots by ensuring consistent luminance across the light guide plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If LED packages are used as point light sources, then the LCD can be thinner and power consumption is reduced, but non-uniform light distribution occurs causing hot spots
Solution Approach 1:
A lens unit is introduced as an intermediary component between the LED packages and the light guide plate. The lens unit includes multiple lenses that refract and redirect light from the point-like LED sources, transforming the light distribution pattern to reduce hot spots and achieve more uniform illumination across the light guide plate surface.
Solution Approach 2:
The invention changes the optical parameters by introducing lenses with specific refractive indices and curvature radii. These lenses modify the light propagation paths, changing the angular distribution and spatial intensity profile of light reaching the light guide plate, thereby converting point-source illumination into a more uniform distribution.
2Device complexity
If LED packages are used as point light sources, then the LCD structure is simplified, but hot spots occur due to concentrated light emission
Solution Approach 1:
The lens unit serves as a mediating optical element that sits between the simple LED package array and the light guide plate. This intermediary structure adds minimal complexity while effectively addressing the hot spot issue through optical refraction and redistribution of light paths.
Solution Approach 2:
The lenses in the lens unit utilize curved surfaces (spheroidal or aspherical shapes) to refract light. The curvature of the lens surfaces is specifically designed to redirect light rays from the LED packages, spreading them out to reduce concentrated hot spots and achieve more uniform illumination across the light guide plate.
3Ease of manufacture
If conventional LED packages are used, then manufacturing is simple, but regions close to LED packages receive excessive light creating bright spots
Solution Approach 1:
The lens unit is positioned as an intermediary layer between the LED packages and the light guide plate, serving as a light redistribution medium. This simple addition maintains the ease of manufacturing LED assemblies while effectively correcting the luminance uniformity issue through optical refraction.
Solution Approach 2:
By introducing lenses with specific optical parameters (refractive index, curvature radius, lens diameter), the invention changes how light is distributed without complicating the manufacturing process. The lenses are designed with standard optical parameters that can be integrated into existing manufacturing workflows.
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 diffuses light emitted from LED packages, reducing luminance variations and minimizing hot spots, thereby enhancing the uniformity of light distribution and improving the overall display quality of LCDs.
Implementation Method 1
a lens unit comprising a plurality of lenses partially overlapping with each other, the lens unit to seal the plurality of LED packages
Implementation Method 2
improves the diffusion of light emitted from a plurality of LED packages and incident on a light guide plate, thereby reducing a hot spot
Data Source
AI summary
A backlight assembly and a liquid crystal display having the same are provided. The backlight assembly includes a plurality of LED packages mounted on a substrate, and a lens unit that seals the LED packages. The lens unit includes a plurality of convex lenses arranged to partially overlap with each other or arranged proximate to each other. Light emitted from LED units in the LED packages is diffused by the interface between the lens unit and another material, such as air, to provide light incident on a light guide plate.