PC-LED Module UV Blue Pump Segmentation
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Solution Overview
Problem
Violet pumped LED lamps face low energy efficiency due to high Stokes loss and scattering losses in the phosphor layer, with violet light being harmful and difficult to tune without efficiency penalties.
Innovation Solution
A lighting device combining UV and blue LEDs with specific luminescent materials that convert blue light into green, yellow, orange, and red light, minimizing UV radiation conversion and reducing Stokes loss, using materials like A3B5O12:Ce3+, MD:Eu, and MGB3N4:Eu classes for efficient wavelength conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If violet light is used to pump phosphors, then color rendering is improved, but energy efficiency deteriorates due to high Stokes loss
Solution Approach 1:
The invention segments the single violet pump source into two separate LED sources: a UV LED (380-420 nm) and a blue LED (440-470 nm). This segmentation allows independent optimization of each pump source's wavelength and power, reducing overall Stokes loss while maintaining color rendering performance.
Solution Approach 2:
The invention changes the pump wavelength parameters by using a combination of UV (380-420 nm) and blue (440-470 nm) wavelengths instead of a single violet wavelength. This parameter change optimizes the excitation spectra of the phosphors, reducing Stokes loss while maintaining effective color rendering.
2Illumination intensity
If phosphor layer optical thickness is increased to improve luminescence down-conversion, then color rendering is improved, but scattering losses increase
Solution Approach 1:
The invention segments the phosphor conversion function into two separate phosphor layers: a first phosphor layer excited by UV light and a second phosphor layer excited by blue light. This segmentation reduces the optical thickness required for each layer, minimizing scattering losses while maintaining effective luminescence down-conversion.
Solution Approach 2:
The invention introduces an intermediary blue LED source that pumps the second phosphor layer, which in turn emits light that combines with UV-pumped phosphor emission and direct blue LED light. This intermediary approach optimizes the optical path and reduces scattering losses in each individual phosphor layer.
3Illumination intensity
If violet light content is increased for enhanced white rendering, then white rendering is improved, but harmful effects increase
Solution Approach 1:
The invention extracts the harmful violet light component (405-430 nm) from the pump spectrum by using UV (380-420 nm) and blue (440-470 nm) LED sources instead. The UV LED operates at wavelengths below the harmful violet range, and the blue LED operates at safer wavelengths, thereby eliminating harmful violet light exposure while maintaining white rendering enhancement through phosphor emission.
Solution Approach 2:
The invention converts the potentially harmful violet light function into a beneficial configuration by using UV and blue LEDs that pump phosphors to emit in the violet-enhanced spectrum. The harmful violet pump light is replaced with safer UV and blue pump lights, while the desired white rendering enhancement is achieved through controlled phosphor emission in the 405-430 nm range.
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 provides high efficiency, high color rendering, and enhanced white rendering with reduced violet light content, achieving efficient energy conversion and improved spectral tuning without efficiency penalties.
Implementation Method 1
a first luminescent material, configured to provide upon excitation with the blue light of the second solid state light source first luminescent material light having a wavelength selected from the green and yellow wavelength range
Implementation Method 2
a second luminescent material, configured to provide upon excitation with the blue light of the second solid state light source second luminescent material light having a wavelength selected from the orange and red wavelength range
Implementation Method 3
a wavelength converter element, wherein the wavelength converter element comprises: a first luminescent material, configured to provide upon excitation with the blue light of the second solid state light source
Data Source
AI summary
The invention provides a lighting device (100) comprising: —a first solid state light source (10), configured to provide UV radiation (11) having a wavelength selected from the range of 380-420 nm; —a second solid state light source (20), configured to provide blue light (21) having a wavelength selected from the range of 440-470 nm; —a wavelength converter element (200), wherein the wavelength converter element (200) comprises: —a first luminescent material (210), configured to provide upon excitation with the blue light (21) of the second solid state light source (20) first luminescent material light (211) having a wavelength selected from the green and yellow wavelength range, and wherein the first luminescent material excitability for UV radiation (11) is lower than for blue light (21); and —a second luminescent material (220), configured to provide upon excitation with the blue light (21) of the second solid state light source (20) second luminescent material light (221) having a wavelength selected from the orange and red wavelength range, and wherein the second luminescent material excitability for UV radiation (11) is lower than for blue light (21).