Angle-Selective Filter for Solid State Illumination Efficiency
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Solution Overview
Problem
Conventional solid state light sources with wavelength conversion struggle to efficiently combine narrow beam excitation light and wide beam excitation light, as the angle selective filter used in existing designs cannot transmit blue LED light with large incident angles, preventing the recycling of reflected excitation light and thus limiting luminescence efficiency.
Innovation Solution
A light source device employing a filter with varying transmittance characteristics based on input angles, allowing both narrow and wide beam excitation lights to pass through while reflecting and recycling excitation light effectively, using a primary and secondary excitation light source with different peak wavelengths and angles of incidence to optimize luminescence efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an angle selective filter is used to recycle reflected excitation light, then luminescence efficiency is improved, but blue LED light with large incident angles cannot pass through the filter
Solution Approach 1:
The patent uses a dynamically adjustable filter system that can change its angular selectivity characteristics. By making the filter properties adjustable rather than fixed, the system can adapt to different excitation light sources and angles, allowing both narrow beam laser light and wide beam LED light to be effectively utilized while maintaining excitation light recycling capability.
Solution Approach 2:
The patent changes the parameters of the filter system by introducing adjustable angular selectivity. The filter's transmittance and reflectance characteristics are made variable through mechanical or optical adjustment mechanisms, enabling the system to optimize performance for different combinations of excitation sources and angles throughout operation.
2Power
If blue LED is added as second excitation light source to enhance luminescence brightness, then light output is improved, but the existing angle selective filter prevents large-angle LED light from passing through
Solution Approach 1:
The patent creates a universal filter system that can handle multiple types of excitation light sources (both narrow beam lasers and wide beam LEDs) with different angular characteristics. The adjustable nature of the filter allows it to perform the same excitation light recycling function across different source types, making the system multi-functional and adaptable to various operational requirements.
3Use of energy by moving object
If excitation light is converted to narrow beam using collimation lens, then luminescence efficiency is improved, but device complexity increases
Solution Approach 1:
Rather than using fixed collimation optics to create narrow beams, the patent employs a dynamic filter system that can adapt to different beam angles. This approach maintains luminescence efficiency by enabling excitation light recycling without requiring complex static optical elements like collimation lenses, thereby reducing overall device complexity while achieving the same functional outcome.
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
Enhances luminescence efficiency by allowing both narrow and wide beam excitation lights to be used simultaneously, with the filter design ensuring that the reflected excitation light is recycled back to the wavelength conversion material, thereby increasing the overall light output.
Implementation Method 1
a filter, which substantially transmits the first excitation light at input angles smaller than a first threshold angle and substantially reflects the first excitation light at input angles greater than a second threshold angle
Implementation Method 2
Some of the excitation light is absorbed by the phosphor and converted to luminescence light (converted light) 28A, but some of the excitation light 24B is reflected by the phosphor film 26 with a Lambertian distribution
Implementation Method 3
a wavelength conversion device carrying a wavelength conversion material, disposed to receive the first and second excitation lights that have passed through the filter, the wavelength conversion material converting a part of the first and second excitation lights into a converted light
Data Source
AI summary
A light source includes two excitation light sources generating two respective excitation lights, a filter, and a wavelength conversion material. The second excitation light has a peak wavelength shorter than that of the first excitation light. The transmittance curves of the filter are dependent on the input angle. The first and second excitation lights are inputted to the filter at angles smaller than a first threshold angle, and angles between the first and a third threshold angle, respectively. Both excitation lights pass through the filter to excite the wavelength conversion material, which generates a converted light but reflects some of the excitation lights. Part of the reflected first excitation light reaches the filter at input angles greater than a second threshold angle and is reflected by the filter back to the wavelength conversion material for recycling. The third and second threshold angles are greater than the first threshold angle.