Projector Phosphor Light Guide Layout for Fluorescence Extraction
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Solution Overview
Problem
The existing light source devices in projectors using phosphors suffer from a decrease in fluorescence use efficiency due to components of fluorescence leaking out through interfaces with air layers at angles smaller than the critical angle, leading to inefficient light propagation and emission.
Innovation Solution
A light source device with a first light source emitting first light, a wavelength conversion element, a first optical member, a first light guide, a first reflecting member, and a support member, where the wavelength conversion element is supported and the light guide directs converted light efficiently, minimizing losses through total internal reflection and enhancing extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fluorescence propagates through the wavelength conversion member by total internal reflection at interfaces with air layers, then light guidance is achieved, but fluorescence use efficiency decreases due to leakage at angles smaller than the critical angle
Solution Approach 1:
The patent introduces a light guide member as an intermediary substance between the wavelength conversion member and the air layer. This light guide member has a refractive index that is lower than the wavelength conversion member but higher than air, creating a gradient that enables total internal reflection while preventing fluorescence leakage. The intermediary layer resolves the contradiction by providing a reliable optical interface that maintains guidance efficiency without the energy loss associated with direct air contact interfaces.
2Device complexity
If a simple plate-like wavelength conversion member is used, then device complexity is reduced, but fluorescence extraction efficiency decreases due to interfaces with air layers
Solution Approach 1:
The light guide member serves as an intermediary that is integrated with the simple plate-like structure of the wavelength conversion member. Rather than complicating the basic plate design, the light guide member enhances it by providing the necessary optical interface properties. This maintains structural simplicity while eliminating the energy loss that would otherwise occur at air interfaces, thus resolving the contradiction between simplicity and efficiency.
3Productivity
If excitation light enters a large area plane of the wavelength conversion member, then light input efficiency is improved, but fluorescence leakage through interfaces increases
Solution Approach 1:
The light guide member acts as an intermediary that extends throughout the wavelength conversion member, providing continuous optical guidance from the large area input plane to the output. This allows excitation light to efficiently enter through the large area while the light guide member prevents fluorescence leakage along the entire propagation path, resolving the contradiction between high light input efficiency and prevention of fluorescence leakage.
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 improves fluorescence use efficiency by reducing losses and enhancing the extraction of converted light, thereby increasing the overall light output and reducing temperature-related inefficiencies in the wavelength conversion process.
Implementation Method 1
there has been proposed a light source device using fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light emitting element
Implementation Method 2
the fluorescence generated inside the wavelength conversion member propagates through the interior of the wavelength conversion member by being totally reflected by interfaces between surfaces of the wavelength conversion member and an air layer
Data Source
AI summary
A light source device according to the present disclosure includes a first light source that emits first light, a wavelength conversion element that converts the first light into second light, a first optical member that transmits the first light and reflects the second light, a first light guide that guides the second light, a first reflecting member that reflects the first light and the second light, and a support member that supports the wavelength conversion element. The wavelength conversion element has a first surface on which the first light is incident, second and third surfaces crossing the first surface and facing opposite sides, and fourth and fifth surfaces crossing the first, second, and third surfaces and facing opposite sides. The first reflecting member is disposed at the second surface side of the wavelength conversion element and the first light guide, the second light is emitted from the third surface side of the first light guide, and the support member has a first support portion that supports the fourth surface and a second support portion that supports the fifth surface. The first optical member covers an opposite side to the wavelength conversion element of the first light guide disposed between the first support portion and the second support portion.