Light Guide Phosphor Thermal Management
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Solution Overview
Problem
High intensity light sources, particularly white light sources, face challenges with heat generation and mechanical reliability due to the need for high-quality red phosphor materials and thermally stable glues, leading to increased costs and reduced system reliability.
Innovation Solution
A light emitting device with a light guide having a luminescent material and a phosphor element arranged adjacent to a reflective element, allowing for efficient light conversion and emission with a broader spectral distribution, while reducing heat transfer and mechanical stress through a thinner phosphor element and improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-quality red phosphor material and thermally stable glue are used to ensure optical quality and mechanical reliability, then system reliability and optical performance are improved, but manufacturing costs increase
Solution Approach 1:
The patent removes the glue layer from the optical path between the red phosphor and the lens. By extracting this problematic intermediate layer, the design eliminates the need for thermally stable glue while maintaining mechanical reliability through direct contact between the phosphor and lens, thereby reducing manufacturing costs without sacrificing system reliability
Solution Approach 2:
The patent introduces a reflective layer as an intermediary between the red phosphor and the lens. This reflective layer serves dual purposes: it maintains the mechanical connection without requiring thermally stable glue, and it optimizes light extraction by reflecting unwanted wavelengths back into the phosphor, thus improving efficiency while reducing material costs
2Duration of action of stationary object
If high-quality red phosphor material and thermally stable glue are used to ensure mechanical reliability under high temperature gradient conditions, then system durability is improved, but manufacturing costs increase
Solution Approach 1:
The patent extracts the glue layer from the assembly, eliminating the need for thermally stable adhesive materials. The red phosphor is placed in direct contact with the lens, which provides mechanical support and thermal stability without requiring expensive specialized glue, thereby improving durability while reducing manufacturing costs
Solution Approach 2:
The patent changes the thermal management approach by using the lens itself as a heat sink and structural support. The lens material is selected to have appropriate thermal properties, allowing it to directly contact the phosphor and manage heat gradients without requiring additional thermally stable bonding materials, thus improving durability at lower cost
3Use of energy by moving object
If a thick phosphor element is used to ensure adequate light conversion, then optical conversion efficiency is improved, but heat transfer increases and mechanical stress increases
Solution Approach 1:
The patent optimizes the phosphor layer thickness to a minimal value that still provides adequate light conversion. By thinning the phosphor layer, the path length for heat generation is reduced, minimizing heat transfer to surrounding components. The reflective layer compensates for the reduced thickness by reflecting unconverted light back into the phosphor, maintaining conversion efficiency while reducing thermal load
Solution Approach 2:
The patent converts the potentially harmful effect of light passing through the phosphor without conversion into a beneficial effect by using the reflective layer to redirect this light back into the phosphor. This secondary pass through the phosphor increases conversion efficiency without requiring a thicker initial layer, thereby reducing heat generation and mechanical stress while maintaining optical performance
4Use of energy by moving object
If a thick phosphor element is used to ensure adequate light conversion, then optical conversion efficiency is improved, but mechanical stress increases
Solution Approach 1:
The patent reduces the phosphor layer thickness to minimize mechanical stress while maintaining adequate light conversion through the reflective layer's light-recycling function. The thinner phosphor layer experiences less mechanical stress from thermal expansion and mounting forces, improving reliability without sacrificing optical performance
Solution Approach 2:
The reflective layer converts light that would otherwise be lost into additional conversion opportunities, allowing the phosphor layer to be thinner. This thinner layer experiences reduced mechanical stress while the reflective layer ensures adequate overall conversion efficiency by recycling unconverted light back through the phosphor
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 a high-intensity, reliable, and cost-effective light source with improved thermal management and mechanical durability, enabling the production of white light with enhanced quality and efficiency.
Implementation Method 1
a light guide adapted for converting the light with the first spectral distribution to light with a second spectral distribution... the light guide being made of a luminescent material
Implementation Method 2
a phosphor element arranged adjacent to the first further surface, the phosphor element being adapted for converting light incident from the light guide to third light with a third spectral distribution
Implementation Method 3
a light guide comprising a light input surface and a light exit surface extending in an angle different from zero to one another... guiding the second light with the second spectral distribution to the light exit surface and coupling the second light with the second spectral distribution out of the light exit surface
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A light emitting device (1) comprising at least one light source (2) adapted for, in operation, emitting first light (13) with a first spectral distribution, a light guide (4) made of a luminescent material and comprising a light input surface (41) and a light exit surface (42) extending in an angle different from zero to one another, the light guide further comprising a first further surface (46) extending parallel to and arranged opposite to the light exit surface, wherein the light guide is adapted for receiving the first light (13) with the first spectral distribution at the light input surface, converting at least a part of the first light with the first spectral distribution to second light (14) with a second spectral distribution, guiding the second light with the second spectral distribution to the light exit surface and coupling the second light with the second spectral distribution out of the light exit surface. The light emitting device further comprises a phosphor element (77) arranged adjacent to the first further surface and a reflective element (76) arranged adjacent the phosphor element opposite to the first further surface (46). The phosphor element is adapted for converting light incident from the light guide to third light (17) with a third spectral distribution and the light guide (40) is furthermore adapted for receiving the third light (17) with the third spectral distribution at the first further surface (46), guiding the third light (46) with the third spectral distribution to the light exit surface (42) and coupling the third light with the third spectral distribution out of the light exit surface.