Two-Layer LED Lens with Titanium Dioxide for Uniform Light Distribution
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Solution Overview
Problem
Conventional LED devices suffer from reduced light extraction efficiency and uneven light distribution due to the use of non-epoxy resin encapsulants that yellow under UV exposure and require additional optical lenses for light diffusion, which is not feasible in ultra-thin display devices with limited space.
Innovation Solution
A two-layer lens structure using silicone epoxy resin with varying titanium dioxide content, where the first layer enhances light extraction efficiency and the second layer alters the light pattern, allowing for improved light refraction and distribution without the need for secondary optical lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-epoxy resin encapsulant is used, then light extraction efficiency is maintained initially, but the encapsulant yellows under UV exposure over time, reducing light extraction efficiency
Solution Approach 1:
The patent changes the chemical composition parameters of the encapsulant by using silicone epoxy resin instead of conventional non-epoxy resin, and by controlling the titanium dioxide content within 0-5 weight percent. This parameter change ensures the encapsulant maintains its optical properties and does not yellow under UV exposure, thereby improving long-term light extraction efficiency.
Solution Approach 2:
The patent employs a composite material system consisting of silicone epoxy resin combined with controlled amounts of titanium dioxide. This composite structure provides both the protective encapsulation function and UV resistance, preventing the yellowing issue while maintaining light extraction efficiency over time.
2Productivity
If conventional single-layer encapsulant is used, then device structure is simple, but light distribution is uneven and light extraction efficiency is insufficient
Solution Approach 1:
The patent segments the encapsulant into multiple layers with different titanium dioxide content. The first encapsulant layer has a first titanium dioxide content while the second encapsulant layer has a second titanium dioxide content, creating functional segmentation that improves both light extraction efficiency and light distribution uniformity without requiring additional optical components.
Solution Approach 2:
Different regions of the encapsulant are assigned different titanium dioxide concentrations to achieve localized optical functions. The first encapsulant layer near the LED chip uses one titanium dioxide content for optimal light extraction, while the second layer uses a different content for light distribution control, implementing local quality optimization throughout the encapsulant structure.
3Illumination intensity
If secondary optical lens is added to diffuse light, then light distribution uniformity improves, but device height increases beyond the limit of ultra-thin display devices
Solution Approach 1:
The patent merges the light diffusion function with the encapsulant structure itself. By incorporating multiple encapsulant layers with different titanium dioxide content, the encapsulant performs both protective and optical diffusion functions that were previously required separate components, thereby achieving uniform light distribution without increasing device height.
Solution Approach 2:
The multi-layer encapsulant structure serves multiple functions simultaneously: it protects the LED chip, manages UV exposure, controls light extraction efficiency, and diffuses light for uniform distribution. This universal design eliminates the need for separate secondary optical lenses, maintaining the ultra-thin profile while achieving desired light distribution.
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 two-layer lens structure increases light extraction efficiency and achieves a more uniform light distribution, enabling thinner display devices with enhanced light mixing and reduced light refraction distances, overcoming the limitations of conventional designs.
Implementation Method 1
the first lens is disposed over the LED chip and configured to increase the light extraction efficiency
Implementation Method 2
the first lens comprises a first content of titanium dioxide
Implementation Method 3
the second lens is disposed over the first lens and configured to change the light pattern
Implementation Method 4
the second lens comprises a second content of titanium dioxide
Implementation Method 5
the first lens comprises a first content of titanium dioxide. A second lens is disposed over the first lens and configured to change the light pattern, and the second lens comprises a second content of titanium dioxide
Implementation Method 6
allowing for improved light refraction and distribution
Data Source
AI summary
A light-emitting diode (LED) device includes: an LED chip, a first lens, and a second lens. The first lens is disposed over the LED chip and configured to increase the light extraction efficiency of the LED device, and the first lens includes a first content of titanium dioxide. The second lens is disposed over the first lens and configured to alter the light pattern of the LED device, and the second lens includes a second content of titanium dioxide. The second content of titanium dioxide is more than the first content of titanium dioxide.