Optical Lens with Segmented Refractive Indices for LCD Backlight Uniformity
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Solution Overview
Problem
Conventional light emitting diode (LED) packages used in liquid crystal display (LCD) backlight units suffer from non-uniform light distribution, leading to hot spots and increased thickness due to the need for multiple lenses and complex assembly processes, which complicates the fabrication and affects picture quality.
Innovation Solution
A light emitting device package with an optical lens having a refracting surface and recesses to uniformly distribute light emitted from multiple LEDs, allowing light to be refracted and discharged upwards, reducing the number of parts and assembly complexity, and enabling efficient heat radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional dome-shaped lens is used with LED, then light can be distributed within a predetermined region, but uniform light characteristic cannot be obtained and thickness of LCD system increases
Solution Approach 1:
The lens surface is divided into multiple regions with different functions: a first region with a first refractive index for emitting light in a first direction, and a second region with a second refractive index for emitting light in a second direction. This segmentation allows different parts of the lens to control light distribution independently, achieving uniform illumination without increasing thickness.
Solution Approach 2:
Different regions of the lens are assigned different optical properties (refractive indices) to perform different functions. The first region has optimized properties for directing light in one direction while the second region has optimized properties for another direction, allowing precise local control of light distribution to achieve uniformity.
2Illumination intensity
If multiple lenses and complex assembly processes are used to achieve uniform light distribution, then light uniformity can be improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple lens functions are merged into a single lens structure. Instead of using multiple separate lenses to achieve uniform light distribution, the invention integrates different light-directing functions into one lens with multiple regions having different refractive indices, thereby reducing part count and assembly complexity while maintaining light uniformity.
Solution Approach 2:
The single lens structure performs multiple functions simultaneously: it directs light in different directions through different regions, achieves uniform illumination, and eliminates the need for additional optical components. This multi-functionality reduces overall device complexity.
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 achieves uniform light emission and reduced thickness in LCD panels, improving backlight efficiency and power consumption while simplifying the assembly process and enhancing heat radiation efficiency.
Implementation Method 1
an optical lens attached on an upper surface of the package body having a refracting surface for emitting light emitted from the package body and discharging the light to an outside
Data Source
AI summary
A light emitting device package including light emitting devices, and optical lenses respectively disposed over the light emitting devices. Further, a respective optical lens includes an extending member extending from a body of the respective optical lens, and including a first portion laterally extending in a first direction substantially perpendicular to the central axis of the respective light emitting device, and a second portion extending towards the substrate in a second direction substantially parallel with the central axis of the respective light emitting device. A vertical cross section of the second portion is substantially symmetrical with respect to an axis that is spaced apart in the first direction from and substantially parallel with the central axis of the respective light emitting device.