Translucent Alumina UV Window Material for High Thermal Conductivity
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Solution Overview
Problem
Conventional quartz window materials for ultraviolet light emitting devices have low thermal conductivity and low transmittance for wavelengths of 300 nm or less, leading to heat retention and potential device failure.
Innovation Solution
A translucent alumina substrate with a thickness of 0.3 mm or less, featuring a mirror-polished light outgoing surface and a roughened light entering surface, is used to enhance thermal conductivity and transmittance, produced through gel casting or tape casting processes with specific surface roughness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If quartz is used as window material, then the device can be protected and manufactured with good productivity and cost, but the thermal conductivity is low (approximately 1 W/m·K) causing poor heat release
Solution Approach 1:
The patent changes the material parameter from quartz to translucent alumina, which fundamentally alters the thermal conductivity from approximately 1 W/m·K to 30 W/m·K or more. This parameter change resolves the contradiction by maintaining manufacturability while dramatically improving heat release efficiency, allowing the window material to simultaneously protect the device and efficiently dissipate heat.
2Ease of manufacture
If quartz is used as window material, then the device structure is simple and easy to manufacture, but the front total light transmittance for wavelengths of 300 nm or less is significantly low
Solution Approach 1:
The patent changes the material composition parameter from quartz to translucent alumina with specific grain size control (6 to 60 μm). This parameter change simultaneously improves ultraviolet light transmittance for wavelengths of 300 nm or less while maintaining manufacturing simplicity through established ceramic processing techniques, resolving the contradiction between manufacturing ease and optical performance.
3Temperature
If the substrate thickness is reduced to 0.3 mm or less, then the heat release efficiency is improved and ultraviolet light transmittance is enhanced, but the mechanical strength and durability are reduced
Solution Approach 1:
The patent changes the material properties of translucent alumina, specifically controlling grain size (6 to 60 μm) and achieving high thermal conductivity (30 W/m·K or more). These parameter changes allow the material to maintain high mechanical strength even at reduced thicknesses of 0.3 mm or less, while simultaneously improving heat release efficiency and ultraviolet light transmittance, thus resolving the contradiction between thinness and strength.
4Illumination intensity
If the light outgoing surface is mirror-polished to reduce surface roughness, then the ultraviolet light transmittance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent changes the surface roughness parameter to a specific range (0.2 to 0.6 μm) that optimizes ultraviolet light transmittance without requiring mirror-polishing. This parameter change resolves the contradiction by achieving high transmittance through controlled roughness rather than mirror-smooth surfaces, thereby maintaining manufacturing simplicity while improving optical performance.
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 alumina substrate achieves high thermal conductivity of 30 W/m·K or more, efficiently releasing heat and maintaining high transmittance for ultraviolet light, preventing device breakdown due to temperature rise.
Implementation Method 1
the translucent alumina substrate has a high thermal conductivity of 30 W/m·K or more, and thus can efficiently release heat generated in operation of the ultraviolet light emitting device
Implementation Method 2
the light outgoing surface has a surface roughness Ra of 0.03 μm or less, and thus the window material can exhibit a high transmittance of ultraviolet light
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention pertains to a window material for an ultraviolet-ray-emitting element and a method for producing the same. The window material (10) is for use in an ultraviolet-ray-emitting element and is positioned on at least the ultraviolet-ray-emitting side of an ultraviolet-ray-emitting element for emitting an ultraviolet ray (12) having a wavelength of 300nm or less. The window material (10) for an ultraviolet-ray-emitting element comprises a light-transmitting alumina substrate (14), and the average particle diameter of the surface thereof is 6-60µm. As a result, this window material (10) for an ultraviolet-ray-emitting element has high thermal conductivity, is capable of ensuring a high transmission rate of ultraviolet rays of 300nm or less, and is favorable for use in an ultraviolet-ray-emitting element.