Light Conversion Modules With Glass Phosphors and Reflective Filters
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Solution Overview
Problem
Light conversion modules using LEDs face challenges such as low optical power, size constraints due to large phosphor volumes, degradation of phosphor matrices by high optical power and heat, and human eye-safety risks, particularly with ultraviolet light sources.
Innovation Solution
The development of light conversion modules utilizing multiple laser diodes with glass phosphors and optical filters, which resist degradation and reduce eye-safety risks, allowing for compact designs suitable for applications like camera flashes and automotive headlighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If laser diodes are used to increase optical power, then optical power is improved, but heat generation and phosphor degradation worsen
Solution Approach 1:
The patent uses glass phosphor materials combined with silicone or polymer matrices to create composite light conversion layers. The glass phosphor particles (e.g., Y3Al5O12:Ce, Lu3Al5O12:Ce) are suspended in the matrix material, creating a composite structure that can withstand high optical power and heat from laser diodes while maintaining conversion efficiency.
Solution Approach 2:
The patent changes the material parameters by transitioning from organic phosphor matrices to inorganic glass phosphors with higher thermal stability. This parameter change allows the system to operate at higher temperatures without degradation, enabling the use of high-power laser diodes.
2Productivity
If large phosphor volumes are used to compensate for low LED optical power, then optical output is improved, but module size increases
Solution Approach 1:
The patent changes the light source parameters by using laser diodes with higher optical power density compared to LEDs. This allows achieving the same or higher optical output with significantly smaller phosphor volumes, thereby reducing overall module size.
Solution Approach 2:
The patent extracts the unnecessary volume by using high-power laser diodes that require minimal phosphor material to achieve the desired optical output, removing the need for large phosphor volumes required by low-power LEDs.
3Adaptability or versatility
If ultraviolet light sources are used to enable wider phosphor range, then phosphor selection flexibility is improved, but human eye-safety risk worsens
Solution Approach 1:
The patent introduces an optical filter as an intermediary component between the ultraviolet laser diode and the environment. The filter selectively transmits the converted visible light while blocking the harmful ultraviolet radiation, maintaining phosphor selection flexibility while ensuring human eye safety.
Solution Approach 2:
The patent converts the potentially harmful ultraviolet radiation into beneficial visible light through the phosphor conversion process. The ultraviolet laser diode excites the phosphor materials, which then emit visible light, transforming the harmful UV energy into useful visible illumination.
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 enables light conversion modules with enhanced optical power and heat resistance, reducing size and eye-safety concerns while maintaining high conversion efficiency and aesthetic appeal.
Implementation Method 1
a light conversion module such as a camera flash can include a light-emitting diode (LED) and a phosphor (e.g., Ce+:YAG). When the light emission illuminates the phosphor, the phosphor can generate a converted light emission of another wavelength or range of wavelengths.
Implementation Method 2
optical filters which, in some instances, can reduce or eliminate human eye-safety risk. In some implementations, the light conversion modules include optical filters configured to reflect a portion of the light emission generated from the laser diode back onto the phosphor.
Data Source
AI summary
The present disclosure describes light conversion modules each having a single laser diode or multiple laser diodes. The light conversion modules can be particularly small in size (height and lateral footprint) and can overcome various challenges associated with the high optical power and heat emitted by laser diodes. In some implementations, the light conversion modules include glass phosphors, which, in some instances, can resist degradation caused by the optical power and/or heat generated by the laser diodes. In some instances, the light conversion modules include optical filters which, in some instances, can reduce or eliminate human eye-safety risk.