White Light Generation Using Converter Optical Coating
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Solution Overview
Problem
Existing white light generating arrangements require precise adjustment of converter material parameters, such as doping, light scattering, and thickness, to achieve the correct spectral ratio of blue to yellow light, limiting tolerance and material flexibility.
Innovation Solution
An arrangement using an excitation light source for blue light and a converter with an optical coating or scattering layer to adjust the color location, allowing for greater tolerances in material parameters, where the converter's thickness ensures complete conversion of blue light to yellow light, and the optical coating or scattering layer regulates the mixing ratio of blue and yellow light to produce white light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the converter thickness and material parameters are precisely adjusted to achieve the correct spectral ratio of blue to yellow light, then white light quality is improved, but manufacturing complexity and tolerance requirements increase
Solution Approach 1:
The patent introduces a reflector as an intermediary component between the converter and the exit surface. The reflector captures and redirects blue light that passes through the converter back into the converter material, allowing for better mixing of blue and yellow light components. This mediator enables achieving white light quality with more relaxed converter parameter tolerances, as the reflector compensates for insufficient conversion by providing additional light paths.
Solution Approach 2:
The patent adds a spatial dimension by introducing a reflector at an angle to the optical path. Instead of relying solely on the converter thickness (one-dimensional parameter), the solution uses angular reflection to create additional light interaction paths. This dimensional change allows for achieving the desired spectral ratio with less precise converter parameters.
2Ease of manufacture
If conventional converter materials are used without optical coating, then the structure is simpler, but the ability to achieve white light is limited
Solution Approach 1:
The patent applies optical coatings with specific reflection characteristics to the converter surface. By changing the optical parameters (reflection factor R=0.1 to R=0.3 in the blue wavelength range) through coating rather than changing the bulk material properties, the system achieves white light generation capability while maintaining simplicity in the converter structure itself. The coating provides the necessary optical control without complicating the converter manufacturing.
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
Enables the generation of white light with increased material parameter tolerances, allowing for the use of converter materials that cannot achieve white light through conversion alone, by effectively mixing reflected blue and remitted yellow light, resulting in a stable white light appearance.
Implementation Method 1
a converter for converting substantially all the entering blue light into yellow light
Implementation Method 2
the surface of the converter is provided with an optical coating... white light can be mixed from reflected blue light and remitted yellow light
Implementation Method 3
an advantage of such a layer is that the portion of excitation light which is reflected, is not reflected specularly but diffusely, i.e. is backscattered
Data Source
AI summary
An arrangement for generating white light is provided. The arrangement generates the white light by combining blue light and yellow light. The yellow light originates from a converter which transforms into yellow light virtually all blue light that enters the converter.