Stacked Phosphor Layers for Projector Color Tone Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light source apparatuses for projectors face challenges in adjusting the color tone of exiting light without compromising wavelength conversion efficiency, particularly due to gaps between phosphor layers and limitations in optical system configuration.
Innovation Solution
A wavelength conversion element with a substrate having a first phosphor layer and a second phosphor layer, where the second phosphor layer is in contact with part of the first phosphor layer's excitation surface, and a reflection layer between them, allowing for efficient wavelength conversion and adjustable color tone without gaps, enabling the light to exit in the same direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phosphor layers are arranged side by side to adjust color tone, then color adjustment capability is improved, but gaps between phosphor layers reduce wavelength conversion efficiency
Solution Approach 1:
The patent transitions from arranging phosphor layers side by side in the same plane to stacking them in multiple layers along the optical path direction. This dimensional change allows phosphor layers to be positioned at different depths (first phosphor layer closer to the light source, second phosphor layer farther away) without creating gaps, thereby maintaining high wavelength conversion efficiency while enabling color tone adjustment through selective wavelength conversion at different layers.
Solution Approach 2:
The patent divides the wavelength conversion function into multiple segments by using different phosphor materials in separate layers. The first phosphor layer converts a portion of the excitation light to a first wavelength, while the second phosphor layer converts another portion to a second wavelength. This segmentation allows independent optimization of each layer's conversion efficiency and enables flexible color tone adjustment by controlling the thickness and material composition of each layer.
2Adaptability or versatility
If multiple phosphor layers are placed adjacent to each other, then color tone adjustment is enabled, but manufacturing precision becomes difficult to achieve
Solution Approach 1:
By arranging phosphor layers in the depth direction (along the optical path) rather than side by side in the lateral direction, the patent eliminates the need for extremely precise lateral alignment. The stacked configuration allows each phosphor layer to be formed independently at different positions along the optical axis, significantly reducing manufacturing complexity and improving ease of production while maintaining color adjustment capability.
3Adaptability or versatility
If green light and blue light exit via opposite surfaces, then color tone adjustment is achieved, but optical system configuration is restricted
Solution Approach 1:
The patent uses the depth dimension (optical path direction) to separate different wavelength conversion functions rather than using lateral separation. Both the first and second phosphor layers are positioned along the optical path from the light source, allowing converted light wavelengths to exit through the same surface. This configuration simplifies the optical system by eliminating the need for complex beam combining optics and allows for more flexible projector design.
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 maintains high wavelength conversion efficiency while allowing for precise adjustment of the color tone and reduces the likelihood of color breakup, resulting in a high-luminous-flux projector.
Implementation Method 1
a first phosphor layer that has a first excitation light incident surface on which excitation light having a first wavelength is incident, is so provided as to face the first surface, and converts in terms of wavelength the excitation light into light having a second wavelength different from the first wavelength
Implementation Method 2
a second phosphor layer that is so provided as to be in contact with part of the first excitation light incident surface and converts in terms of wavelength the excitation light into light having a third wavelength different from the first and second wavelengths
Implementation Method 3
a reflection layer that is provided between the first phosphor layer and the substrate and reflects the light having the second wavelength and the light having the third wavelength
Data Source
AI summary
A wavelength conversion element includes a substrate having a first surface, a first phosphor layer that has a first excitation light incident surface on which excitation light having a first wavelength is incident, is so provided as to face the first surface, a second phosphor layer that is so provided as to be in contact with part of the first excitation light incident surface, and a reflection layer that is provided between the first phosphor layer and the substrate. The first phosphor layer has an annular shape. The area of the second phosphor layer viewed in the direction in which the excitation light is incident is smaller than the area of the first phosphor layer viewed in the direction in which the excitation light is incident. The thickness of the second phosphor layer is smaller than the thickness of the first phosphor layer.