Fluorescent Wheel Polarization Control for Projector Color Reproducibility
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Solution Overview
Problem
Existing light source devices for projectors suffer from decreased color reproducibility due to unconverted blue light mixing with red and green light, affecting the accuracy of color images displayed.
Innovation Solution
A light source device comprising a light emitting element, a fluorescent wheel with a reflection area and a mirror that reflects and converts light polarization, where the fluorescent wheel's polarization conversion layer is inclined at 45 degrees to separate blue light from red and green light, preventing mixing and enhancing color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phosphor layer is used to convert blue light into red and green light, then color reproduction is improved, but unconverted blue light mixes with red and green light causing decreased color reproducibility
Solution Approach 1:
The fluorescent wheel is divided into distinct functional areas: a fluorescent area that converts blue light to red and green wavelengths, and a reflection area that reflects blue light. This segmentation ensures that converted and unconverted blue light follow separate paths, preventing mixing and maintaining color reproducibility.
Solution Approach 2:
A polarization conversion layer with its optical axis inclined at 45 degrees is introduced as an intermediary between the fluorescent area and the dichroic mirror. This layer converts the polarization direction of reflected blue light, enabling the dichroic mirror to selectively transmit it while blocking converted red and green light, thus preventing color mixing.
2Measurement precision
If a dichroic mirror is used to separate red and green light, then color separation is improved, but blue light passes through and mixes with other colors
Solution Approach 1:
The polarization conversion layer is positioned before the dichroic mirror to pre-convert the polarization direction of reflected blue light. This preliminary action ensures that when the light reaches the dichroic mirror, its polarization state is optimized for transmission, allowing the mirror to selectively pass blue light while blocking red and green light.
3Measurement precision
If the polarization conversion layer optical axis is inclined at 45 degrees, then blue light polarization conversion is optimized, but device complexity increases
Solution Approach 1:
The optical axis of the polarization conversion layer is precisely inclined at 45 degrees relative to the polarization direction of incident blue light. This specific parameter change optimizes the polarization conversion efficiency, ensuring maximum separation of blue light from converted wavelengths while maintaining a relatively simple optical architecture.
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 effectively suppresses blue light mixing, improving color reproducibility by ensuring that blue, green, and red light paths are distinct, resulting in more accurate and vibrant color images projected by the projector.
Implementation Method 1
a fluorescent area configured to convert the light of the first wavelength band into fluorescent light
Implementation Method 2
a polarization conversion layer including an optical axis and converts a polarization direction of either the incident first polarization direction or the incident second polarization direction to another polarization direction
Implementation Method 3
The mirror is configured to reflect a component in a first polarization direction of the light of the first wavelength band and to transmit a component in a second polarization direction of the light of the first wavelength band
Data Source
AI summary
A light source device includes a light emitting element emitting light of a first wavelength band, a fluorescent wheel and a mirror. The fluorescent wheel includes a fluorescent area converting the light of the first wavelength band into fluorescent light and a reflection area reflecting the light of the first wavelength band. The minor reflects a component in a first polarization direction of the light of the first wavelength band and transmits a component in a second polarization direction orthogonal to the first polarization direction. The reflection area includes a reflecting surface and a polarization conversion layer including an optical axis and converts either the first or second polarization direction to another polarization direction. The optical axis of the polarization conversion layer is inclined by 45 degrees to a polarization direction of the light of the first wavelength band at an irradiation position thereof in the fluorescent wheel.