Light-emitting Device Segmentation for Lambertian Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light-emitting devices with phosphor-converted electroluminescent (pcLEDs) suffer from inefficiencies due to radiationless absorption and backscattering effects in the phosphor material, resulting in a non-Lambertian light distribution and significant color changes with viewing angle.
Innovation Solution
A light-emitting device design that separates primary radiation into two parts, where one part enters a light-scattering element to generate a Lambertian distribution and the other part enters a conversion element for partial conversion, avoiding radiationless absorption by bypassing the conversion element, and using a lens for desired light deflection and focusing, along with a ceramic conversion element and light-scattering particles to enhance efficiency and color adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the LED is completely enveloped by the phosphor layer to achieve homogeneous color mixing, then color homogeneity is improved, but radiationless absorption losses increase and luminous efficacy deteriorates
Solution Approach 1:
The patent segments the light path by dividing the optical system into two distinct channels: (1) primary radiation that passes through the phosphor layer without conversion to achieve Lambertian distribution, and (2) primary radiation that is converted to secondary radiation for color mixing. This segmentation allows each channel to optimize its function independently, reducing overall energy loss while maintaining color homogeneity.
Solution Approach 2:
The invention extracts a portion of the primary radiation (first part) from the conversion path and directs it through the phosphor layer without absorption. This extracted component provides the Lambertian distribution and unconverted blue light needed for color balance, eliminating the radiationless absorption losses that would occur if all primary radiation passed through the phosphor material.
2Ease of manufacture
If a phosphor powder layer is used for light conversion, then manufacturing ease is improved, but intrinsic scattering power increases causing backscattering effects and reduced efficiency
Solution Approach 1:
The patent introduces a dedicated light-scattering element as an intermediary component with controlled scattering properties. This separate scattering element has optimized particle size and distribution to provide the desired Lambertian distribution without the excessive intrinsic scattering and backscattering effects of conventional phosphor powder layers, thereby improving efficiency while maintaining ease of manufacture through modular assembly.
3Adaptability or versatility
If the primary radiation passes through the phosphor layer for conversion, then color conversion is achieved, but radiationless absorption processes occur reducing overall efficiency
Solution Approach 1:
The patent segments the primary radiation into two parts: a first part that bypasses the phosphor layer to avoid absorption losses and provides Lambertian distribution, and a second part that undergoes conversion for color adjustment. This segmentation ensures that only the necessary portion of primary radiation undergoes conversion, minimizing radiationless absorption while maintaining color versatility.
Solution Approach 2:
The invention changes the optical parameters by allowing unconverted primary radiation to contribute to the final light output. By adjusting the ratio of converted to unconverted light and optimizing the scattering properties, the system achieves desired color points with higher overall efficiency, as unconverted blue light has higher luminous efficacy than converted yellow light.
4Illumination intensity
If light-scattering particles are added to achieve Lambertian distribution, then light distribution is improved, but device complexity increases
Solution Approach 1:
The patent merges the light-scattering function with the existing optical path by positioning the light-scattering element in the light path where it simultaneously provides Lambertian distribution for both converted and unconverted light. This integrated approach achieves the desired illumination pattern without requiring separate complex scattering mechanisms for different light paths, thereby improving distribution quality while limiting complexity increase.
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 achieves improved luminous efficacy and a stable Lambertian light distribution with reduced radiation losses and enhanced miscibility of primary and secondary radiation, allowing for precise color adjustment and increased effectiveness compared to traditional pcLEDs.
Implementation Method 1
the light-scattering element is provided to generate a mixed radiation having a Lambertian light distribution from the first part of the primary radiation
Implementation Method 2
the LED emits a primary radiation, at least a part of which is absorbed by a phosphor layer (conversion element) arranged on the LED, and is re-emitted as longer-wave secondary radiation
Implementation Method 3
the light-emitting device further comprises a lens, which encloses the solid-state light source, the conversion element and the light-scattering element
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A light-emitting device comprising a solid-state light source (3), at least one conversion element (4) and a light- scattering element (6), wherein the solid-state light source (3) is provided to emit a first part (511) of a primary radiation for entry into the light- scattering element (6) and a second part (512) of a primary radiation for entry into the conversion element (4) for at least partial conversion into at least one secondary radiation (521, 522), the light- scattering element (6) is provided to generate a mixed radiation (5) having a Lambertian light distribution pattern from the first part (511) of the primary radiation, the secondary radiation (521, 522) and a portion of the second part (512) of the primary radiation that has not been converted in the conversion element (4), and the first part (511) of the primary radiation leaves the light-emitting device without having passed the conversion element (4).