LED Brightness Enhancement via Angle-Selective Optical Filter
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Solution Overview
Problem
Traditional high-brightness light sources, such as HID lamps and lasers, face limitations including short lifetimes, difficulty in controlling light color, and high manufacturing costs, while solid-state light sources like LEDs need improvements to broaden their applications, particularly in achieving high brightness.
Innovation Solution
The use of an angle-selective optical filter in conjunction with a highly reflective layer within the LED device to enhance light brightness by selectively transmitting light at smaller incidence angles and reflecting larger angle light back into the device, potentially combined with a reflective polarizer and quarter-wave plate for polarization, to increase total flux and output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional light sources (HID lamps, lasers) are used to achieve high brightness, then brightness requirement is met, but lifetime is short and manufacturing cost is high
Solution Approach 1:
The patent changes the emission angle parameter of LED light by introducing an angle-selective optical filter that transmits only light within a specific angular range (±θ degrees from normal), converting omnidirectional emission into directional emission and achieving high brightness without using traditional light sources
2Productivity
If omnibearing reflector with fluorescent pastern is used, then light transmission efficiency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts and removes the complex omnibearing reflector and fluorescent pastern components, replacing them with a simple angle-selective optical filter layer that achieves similar or better light extraction efficiency without the manufacturing complexity of wide-angle cut-off filters or coated optics techniques
Solution Approach 2:
The patent uses a cost-effective angle-selective optical filter instead of expensive omnibearing reflectors with fluorescent materials, reducing manufacturing cost while maintaining light extraction efficiency
3Illumination intensity
If angle-selective optical filter is used to enhance brightness, then light flux is increased, but device complexity increases due to additional components
Solution Approach 1:
The patent merges the angle-selective optical filter directly with the LED chip structure, integrating the filtering function into the existing device architecture rather than adding separate external components, thus minimizing device complexity while maximizing light flux enhancement
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
This configuration results in a low-cost, high-brightness light source with enhanced brightness and efficient polarization, allowing for improved LED performance and efficient coupling to optic fibers, suitable for various applications without requiring specially manufactured LED chips.
Implementation Method 1
The use of an angle-selective optical filter in conjunction with a highly reflective layer within the LED device to enhance light brightness by selectively transmitting light at smaller incidence angles and reflecting larger angle light back into the device
Implementation Method 2
The use of an angle-selective optical filter in conjunction with a highly reflective layer within the LED device to enhance light brightness by selectively transmitting light at smaller incidence angles and reflecting larger angle light back into the device
Implementation Method 3
potentially combined with a reflective polarizer and quarter-wave plate for polarization, to increase total flux and output efficiency
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light source (figure 1) with enhanced brightness includes an angle-selective optical filter (106) and a light emitting diode (100) (LED) having a high reflective layer (104). The angle-selective filter (106) is located on the top surface of emitting diode to pass lights at specified angles. According to one embodiment, the angle-selective filter (106) comprises index-alternating layers. With a reflective polarizer, the light source can produce polarized light with enhanced brightness.