Light Conversion Member With Wavefront-Matched Recessed Portion
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Solution Overview
Problem
Existing light conversion members suffer from reduced incidence efficiency due to Fresnel reflection at the surface of incidence, leading to optical loss and decreased conversion efficiency of excitation light in lighting devices.
Innovation Solution
A light conversion member with a recessed portion on its surface of incidence, featuring a shape that corresponds to the wave front of the laser beam, such as an aspherical surface with diffraction gratings or a recessed portion, is designed to enhance perpendicular incidence and minimize optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a flat surface is used for light conversion member, then manufacturing is simple, but incidence efficiency is reduced due to Fresnel reflection
Solution Approach 1:
The invention applies curvature to the light conversion member by forming a recessed portion with an aspherical surface on the incident surface. This curved surface structure corresponds to the wavefront shape of the incident laser beam, enabling the light to enter perpendicularly to the surface at all points, thereby minimizing Fresnel reflection and maximizing incidence efficiency while maintaining manufacturing feasibility through molding or coating processes.
2Loss of energy
If perpendicular incidence is achieved to minimize Fresnel reflection, then incidence efficiency improves, but surface structure becomes complex
Solution Approach 1:
The invention applies local quality by creating a recessed portion only at the incident surface where light enters, while keeping other surfaces flat or simple. The aspherical surface is localized to the incident area and its curvature is specifically designed to match the laser beam wavefront, achieving perpendicular incidence locally where needed without complicating the entire device structure.
3Productivity
If wavefront-matched surface is used, then conversion efficiency reaches 95% or more, but manufacturing precision requirements increase
Solution Approach 1:
The invention manages manufacturing precision by optimizing the parameters of the aspherical surface, such as the depth and curvature radius of the recessed portion, to balance performance and manufacturability. The surface shape is designed with specific geometric parameters that can be controlled within standard manufacturing tolerances while still achieving wavefront matching and high conversion efficiency of 95% or more.
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 significantly increases light incidence efficiency, achieving conversion efficiencies of 95% or more, and when combined with an anti-reflection layer, reaches efficiencies of 99% or higher.
Implementation Method 1
a shape of the recessed portion is formed to correspond to a wave front shape of the laser beam
Implementation Method 2
some of the excitation light may be lost while incident on the light conversion member by Fresnel reflection of the surface of incidence
Implementation Method 3
an output surface in which a wavelength of the laser beam is converted and the laser beam having the converted wavelength is output
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(d)
AI summary
Disclosed are a light conversion member (20) and a lighting device including the same. The light conversion member (20) includes a surface of incidence which includes a recessed portion (23) and on which a laser beam is incident; and an output surface in which a wavelength of the laser beam is converted and the laser beam having the converted wavelength is output, wherein a shape of the recessed portion (23) is formed to correspond to a wave front shape of the laser beam.