Wavelength Conversion Element Air Layer Design
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Solution Overview
Problem
The existing wavelength conversion elements in illumination devices for projectors suffer from luminous efficiency loss due to fluorescence reflection by the reflecting surface, and thermal management issues lead to decreased performance.
Innovation Solution
A wavelength conversion element with a base member, a wavelength conversion section, and an air layer, where the air layer is positioned to reduce the critical angle of fluorescence reflection and enhance thermal conductivity, along with a rotary device for dynamic excitation light positioning to prevent thermal quenching, and communication holes to manage air expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflecting surface is disposed on the opposite side to the plane of incidence of the excitation light in a wavelength conversion element, then the fluorescence can be reflected and extracted to the outside, but a loss occurs when the fluorescence is reflected by the reflecting surface and the luminous efficiency decreases
Solution Approach 1:
The patent extracts the air layer from between the wavelength conversion section and the base member, positioning it only in the excitation light incident area. This allows the fluorescence extraction function to be maintained while removing the harmful reflection loss, as the air layer acts as an extraction path without causing significant reflection losses for the fluorescence wavelengths.
Solution Approach 2:
The air layer is positioned locally only in the excitation light incident area rather than uniformly across the entire interface. This localized positioning optimizes the balance between fluorescence extraction efficiency and minimizing reflection losses, as the air layer's optical properties are exploited only where excitation light enters the wavelength conversion section.
2Device complexity
If the wavelength conversion section is in direct contact with the base member, then the structure is simple, but thermal management issues lead to decreased performance due to thermal quenching
Solution Approach 1:
The air layer serves as an intermediary between the wavelength conversion section and the base member. While air is generally a thermal insulator, the patent positions the air layer only in the excitation light incident area, allowing thermal contact in other regions through the holding section, thus balancing thermal management with structural simplicity.
Solution Approach 2:
The patent introduces a rotary device that rotates the wavelength conversion element, dynamically positioning the excitation light incident area. This rotation prevents thermal quenching by continuously moving the excited region, allowing heat to dissipate from any given location before it accumulates to quenching temperatures.
3Illumination intensity
If the air layer is disposed between the wavelength conversion section and the base member, then the critical angle of fluorescence reflection is reduced, but air expansion may occur affecting performance consistency
Solution Approach 1:
The patent extracts the air layer to occupy only the excitation light incident area, separating it from the broader interface between the wavelength conversion section and base member. This limited positioning reduces the volume of air that can expand, thereby minimizing the impact of thermal expansion on performance consistency while maintaining the optical benefits in the incident area.
Solution Approach 2:
The patent anticipates air expansion due to thermal effects and compensates for it by limiting the air layer to a small, controlled region. The holding section and recessed part structure constrain the air layer, preventing uncontrolled expansion that would affect performance, while still allowing the air layer to function optically in the excitation incident area.
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 increases luminous efficiency by minimizing light loss and maintaining high thermal conductivity, preventing thermal quenching and air expansion, thereby ensuring consistent performance and reliability.
Implementation Method 1
an air layer disposed in one of a space surrounded by a first recessed part provided to the base member so as to be opposed to the second surface of the wavelength conversion section and the second surface of the wavelength conversion section
Implementation Method 2
the critical angle of fluorescence reflection is reduced
Implementation Method 3
configured to perform a wavelength conversion on the excitation light into fluorescence in a second wavelength band different from the first wavelength band
Implementation Method 4
the holding section may have an adhesive configured to bond the third surface of the wavelength conversion section and the base member to each other
Implementation Method 5
a rotary device for dynamic excitation light positioning to prevent thermal quenching
Implementation Method 6
communication holes to manage air expansion
Data Source
AI summary
A wavelength conversion element according to the present disclosure includes a base member having a reflecting surface, a wavelength conversion section having a first surface which excitation light in a first wavelength band enters, and a second surface opposed to the base member, and configured to perform a wavelength conversion on the excitation light into fluorescence in a second wavelength band, a holding section configured to hold the wavelength conversion section to the base member, and an air layer disposed in one of a space surrounded by a first recessed part provided to the base member so as to be opposed to the second surface of the wavelength conversion section and the second surface of the wavelength conversion section, and a space surrounded by a second recessed part provided to the wavelength conversion section so as to be opposed to the reflecting surface of the base member and the reflecting surface of the base member, wherein in the first surface, at least a part of a portion opposed to the reflecting surface and the air layer is set as an incident area of the excitation light.