Luminescent Screen for Laser Projection Using Blue Light Conversion
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Solution Overview
Problem
Current laser projection systems face challenges due to the lack of suitable laser light sources, particularly diode lasers at proper visible wavelengths, limiting their efficiency and cost-effectiveness for consumer markets, as existing luminescent materials have poor conversion efficiency for blue light emission.
Innovation Solution
A laser projection system utilizing a luminescent layer with BaMgAl11O17:Eu or MSi6−aAlaN8−aOx+a:Eu2+ materials to efficiently convert laser light at 405 nm to blue light, enabling the use of commercially available 405 nm laser diodes and allowing for RGB projection with appropriate selection of laser sources and luminescent materials for red and green light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing luminescent materials (Sr10(PO4)6Cl2:Eu) are used to convert ultraviolet laser light to blue light, then the projection system can be constructed, but the conversion efficiency is poor due to small absorption at 405 nm wavelength
Solution Approach 1:
The patent changes the chemical composition parameters of the luminescent material by using BaMgAl11O17:Eu or MSi6−aAlaN8−aOx+a:Eu2+ instead of Sr10(PO4)6Cl2:Eu. This material parameter change results in significantly improved absorption at 405 nm wavelength, resolving the contradiction between conversion efficiency and absorption strength.
Solution Approach 2:
The patent employs composite luminescent materials with specific dopant concentrations and compositions (BaMgAl11O17:Eu or MSi6−aAlaN8−aOx+a:Eu2+) to achieve both strong absorption at 405 nm and efficient blue light emission, simultaneously improving both parameters that were in contradiction.
2Ease of manufacture
If commercially available 405 nm laser diodes are used, then cost is reduced, but blue light emission efficiency is insufficient with existing luminescent materials
Solution Approach 1:
By changing the luminescent material parameters to BaMgAl11O17:Eu or MSi6−aAlaN8−aOx+a:Eu2+, the system achieves high blue light output efficiency while using commercially available 405 nm laser diodes, thus resolving the contradiction between cost-effectiveness and productivity.
3Ease of operation
If ultraviolet laser light sources are used to excite luminescent material for blue light generation, then the projection system can function, but the system becomes bulky and expensive
Solution Approach 1:
The patent uses 405 nm laser diodes instead of ultraviolet laser sources, changing the excitation wavelength parameter. This allows the system to maintain functionality while using compact, inexpensive laser diodes, thus resolving the contradiction between operational functionality and 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 proposed system achieves significantly improved conversion efficiency for blue light production, enabling compact, cost-effective, and bright RGB projections, making laser projection systems more viable for consumer markets.
Implementation Method 1
The projection screen comprises a luminescent layer which upon excitation by said laser beam emits blue light
Data Source
AI summary
A laser projection system includes at least one laser light source, a projection screen and a spatial light modulator for projecting a laser beam of the laser light source to form an image on the projection screen. The projection screen includes a luminescent layer which upon excitation by the laser beam emits blue light. The luminescent layer contains MSi6−aAlaN8−aOx+a:Eu2+ (with M=Sr, Ba,; 0≦x≦1; 0≦a≦1) as a luminescent material. With this material laser light of a laser diode emitting in the wavelength region of 405 nm can be converted to blue light of 450 nm with high efficiency. The proposed projection system, therefore, is suitable for RGB projection using laser diodes as laser light sources.