Phosphor Optical Element Refractive Index Gradient
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Solution Overview
Problem
Conventional phosphor optical elements face challenges in efficiently directing fluorescent light to a predetermined area, leading to increased light-emitting areas and reduced optical system efficiency due to omnidirectional emission and oblique light components.
Innovation Solution
A phosphor optical element configuration featuring a transparent base with a phosphor-containing member and a cover member, where the phosphor particles are smaller than the incident light wavelength, and optionally using multilayer films or refractive index distributions to control light propagation, reducing parallel light emission and guiding it in a specific direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a phosphor-containing member is used to convert light wavelength, then the light emission area increases, but the optical system efficiency decreases due to omnidirectional emission and oblique light components
Solution Approach 1:
The patent applies local quality by creating a refractive index distribution within the phosphor-containing member that is non-uniform in the vertical direction. The refractive index varies from the first surface to the second surface, causing light to be emitted preferentially in the forward direction rather than omnidirectionally. This resolves the contradiction by maintaining a large light emission area while improving optical system efficiency through directional control of emitted light.
2Loss of energy
If the phosphor-containing member area is reduced to decrease light-emitting area, then optical system efficiency improves, but the alignment accuracy between phosphor optical element and light-emitting element must be increased
Solution Approach 1:
The patent changes the refractive index parameter within the phosphor-containing member to achieve directional light emission. By creating a refractive index distribution that increases or decreases from the first surface to the second surface, the system maintains a large phosphor-containing member area while controlling the light emission direction. This eliminates the need for high alignment accuracy between components, as the large area provides a tolerance margin while the refractive index control ensures proper light direction.
3Loss of energy
If a dichroic mirror is used to reflect fluorescent light, then light utilization efficiency improves, but the device complexity increases
Solution Approach 1:
The patent merges the light reflection function with the phosphor-containing member itself by creating a reflective layer on the second surface. Instead of using a separate dichroic mirror component, the reflection function is integrated into the phosphor-containing member's structure. This reduces device complexity by eliminating additional components while maintaining light utilization efficiency through the reflective layer that redirects emitted light.
4Illumination intensity
If the phosphor particle diameter is increased to improve phosphor conversion efficiency, then the fluorescent light emission intensity increases, but the light emission becomes more omnidirectional
Solution Approach 1:
The patent applies local quality by creating a refractive index distribution within the phosphor-containing member that compensates for the omnidirectional emission from larger phosphor particles. The varying refractive index from the first surface to the second surface directs the emitted light forward, maintaining high emission intensity from larger particles while improving optical system efficiency through directional control.
Solution Approach 2:
The patent uses composite materials by combining phosphor particles with a matrix material that has a different refractive index. This composite structure, with its controlled refractive index distribution, allows larger phosphor particles to be used for high conversion efficiency while the matrix material's optical properties direct the emitted light in the desired direction, resolving the omnidirectional emission issue.
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 allows for a reduced light-emitting area of fluorescent light without decreasing the phosphor-containing member area, enabling better control of light direction for subsequent optical systems.
Implementation Method 1
a phosphor-containing member that includes a transparent member containing a phosphor particle... the phosphor particle has a diameter no greater than the wavelength of the incident light
Implementation Method 2
refractive index distributions to control light propagation, reducing parallel light emission and guiding it in a specific direction
Data Source
AI summary
A phosphor optical element includes: a base member; a phosphor-containing member that includes a transparent member containing a phosphor particle; and a cover member, wherein the base member, the phosphor-containing member, and the cover member are sequentially formed on a transparent base that is transparent to a wavelength of incident light from an excitation light source, the phosphor particle has a diameter no greater than the wavelength of the incident light, and in an arbitrary cross section of the phosphor-containing member in a direction perpendicular to a main surface of the transparent base, the phosphor-containing member has, in a direction perpendicular to the main surface of the transparent base, a thickness no greater than the wavelength of the incident light.