Light Source Device Segmented Phosphor Plate Color Uniformity
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Solution Overview
Problem
Conventional light source devices using LED modules and phosphor plates for white light production suffer from variations in color radiation when projected, causing central blue and peripheral yellow color variations on projection surfaces due to mismatched blue and yellow light emitting regions.
Innovation Solution
A light source device configuration that includes a solid-state light source emitting blue light, a wavelength conversion section (phosphor section) emitting fluorescent light, and wavelength selective or antireflective means between the phosphor section and the light source, ensuring the blue and fluorescent light emitting regions are of equal size without reducing light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the phosphor plate is made larger than the excitation light irradiated spot to facilitate assembly, then the assembly is easier, but the yellow light emitting region becomes larger than the blue light emitting region, causing color variations in radiation
Solution Approach 1:
The phosphor plate is divided into two distinct regions: a first region that emits yellow light when excited by blue light, and a second region that does not emit yellow light. This segmentation allows the blue light emitting region and yellow light emitting region to be equal in size, preventing color variations while maintaining a large overall phosphor plate size for easy assembly.
2Use of energy by moving object
If a wavelength selective filter is used to transmit blue light and reflect yellow light, then light utilization efficiency is improved, but the yellow light is emitted at greater intensity from the peripheral portion, causing color variations
Solution Approach 1:
The phosphor plate is segmented into a first region for yellow light emission and a second region that does not emit yellow light. This segmentation prevents the peripheral portion from emitting excessive yellow light that would cause color variations, while still allowing the wavelength selective filter to improve light utilization efficiency in the first region.
Solution Approach 2:
Different regions of the phosphor plate are given different functional properties: the first region contains phosphor material for yellow light emission, while the second region is free of phosphor or contains non-emissive material. This local differentiation ensures uniform color radiation while maintaining high light utilization efficiency where needed.
3Stability of the object's composition
If the blue light emitting region and yellow light emitting region are made equal in size, then color variations are prevented, but the phosphor plate size must be precisely controlled, increasing manufacturing complexity
Solution Approach 1:
The phosphor plate is divided into a first region with phosphor material and a second region without phosphor or with non-emissive material. This clear segmentation provides distinct manufacturing targets for each region, making it easier to control the sizes of blue and yellow light emitting regions equally, thereby reducing manufacturing complexity despite the precision requirement.
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 effectively prevents color variations in radiation by matching the blue and yellow light emitting regions, enhancing light utilization efficiency and maintaining consistent color across the projection surface.
Implementation Method 1
a solid-state light source configured to emit blue light as excitation light
Implementation Method 2
a wavelength conversion section configured to be excited by the excitation light from the solid-state light source so as to emit fluorescent light longer in wavelength than the light emitted from the solid-state light source
Implementation Method 3
a wavelength selective filter configured to transmit the excitation light from the solid-state light source and to reflect the fluorescent light from the wavelength conversion section
Implementation Method 4
an antireflective section configured to reduce reflection of the excitation light incident on the wavelength conversion section
Data Source
AI summary
A light source device can include a solid-state light source configured to emit blue light as excitation light and a phosphor section which is excited by the excitation light from the solid-state light source and which emits fluorescent light longer in wavelength than the light emitted from the solid-state light source. In the light source device, a wavelength selective member configured to transmit the excitation light from the solid-state light source and to reflect the fluorescent light from the phosphor section can be provided between the phosphor section and the solid-state light source. The size of the wavelength selective member can be less than the size of the phosphor section which can be greater than the size of the excitation light spot irradiated with the solid-state light source.