Light Source Device Dual Wavelength Fluorescent Excitation
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Solution Overview
Problem
Existing light sources for projectors face challenges in balancing the emission spectra of red, green, and blue wavelength regions, leading to inadequate light in specific areas and difficulties in achieving standard color gamuts like DCI and sRGB, particularly with fluorescent substances which struggle to efficiently excite and reproduce colors.
Innovation Solution
A light source apparatus comprising a first light source emitting a first wavelength, a second light source emitting a shorter wavelength, a fluorescent substance excited by both wavelengths, and a wavelength selection member to reflect the second wavelength, optimizing excitation efficiency and color reproducibility by using two light sources with different wavelengths for excitation and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single solid-state light source is used to excite fluorescent substance, then the device structure is simple, but the emission spectrum is unbalanced and color gamut requirements cannot be met
Solution Approach 1:
The single light source is segmented into multiple light sources with different wavelengths (first light source with first wavelength, second light source with second wavelength). Each light source targets specific excitation bands of the fluorescent substance, enabling balanced emission spectrum across red, green, and blue regions while maintaining manageable device complexity through modular configuration.
2Volume of moving object
If fluorescent substance is used for wavelength conversion, then the device is compact, but excitation efficiency is insufficient and light output in specific wavelength regions is inadequate
Solution Approach 1:
Different regions of the fluorescent substance are optimized for different wavelength conversions. The fluorescent substance contains multiple phosphors with distinct characteristics: first phosphor converts first wavelength to red light, second phosphor converts second wavelength to green light, and third phosphor converts to blue light. This local optimization of material properties at different spatial locations achieves high excitation efficiency and sufficient light output in all wavelength regions while maintaining compact device size.
3Illumination intensity
If multiple phosphors are used in fluorescent substance, then color gamut is improved, but manufacturing complexity increases
Solution Approach 1:
The fluorescent substance is formulated as a composite material containing multiple phosphors with complementary emission characteristics. The composite structure integrates first phosphor, second phosphor, and third phosphor in specific ratios and distributions, enabling broad color gamut coverage (DCI and sRGB standards) while using established phosphor synthesis and coating techniques to maintain manufacturing feasibility.
4Productivity
If excitation light wavelength is optimized for fluorescent substance, then excitation efficiency is high, but the light source cannot meet color reproducibility requirements
Solution Approach 1:
The system employs multiple light sources with different wavelength parameters (first wavelength from first light source, second wavelength from second light source) to excite different phosphors. By adjusting the wavelength parameters of each light source to match the excitation peaks of respective phosphors, the system achieves high excitation efficiency for each converter while the combined output satisfies color reproducibility requirements through proper wavelength distribution and intensity balancing.
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
This configuration efficiently excites fluorescent substances, enhances color reproducibility, and ensures sufficient light output in desired wavelength regions, effectively addressing the imbalance in emission spectra and achieving standard color gamuts.
Implementation Method 1
a wavelength conversion member having a wavelength conversion layer formed on a light-transmitting plate for emitting long-wavelength light longer than the excitation light with receipt of the excitation light from the excitation light source
Implementation Method 2
a light-reflecting member equipped with an excitation light transmission window for transmitting the excitation light fitted on one-face side where the excitation light in the wavelength conversion member is incident
Implementation Method 3
a filter member for reflecting the excitation light and transmitting the long-wavelength light fitted on the other face side of the wavelength conversion member
Implementation Method 4
a wavelength selection member provided to face the fluorescent substance, and configured to reflect the light having the second wavelength among light output from the fluorescent substance
Data Source
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AI summary
To implement a light source apparatus that can efficiently excite a fluorescent substance and has favorable color reproducibility. There is provided a light source apparatus including: a first light source configured to output light having a first wavelength λb1 included in a first wavelength region; a second light source configured to output light having a second wavelength λb2 that is included in the first wavelength region, and is shorter than the first wavelength; a fluorescent substance (133) configured to be excited by the light having the first wavelength and the light having the second wavelength to emit light λy in a second wavelength region; and a wavelength selection member (140) provided to face the fluorescent substance (133), and configured to reflect the light having the second wavelength λb2 among light output from the fluorescent substance (133).