Wavelength Selective Heat Radiation Material Microcavity Formation
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Solution Overview
Problem
Conventional methods for manufacturing wavelength selective heat radiation materials face challenges in forming microcavities with aspect ratios greater than 3.0 without roughening the upper cavity wall, leading to reduced emissivity and inefficient heat radiation.
Innovation Solution
The method involves using a mask with predetermined openings to adhere tightly to a base material, followed by anisotropic etching to form microcavities with controlled surface roughness and aspect ratios greater than 3.0, ensuring effective heat radiation by suppressing surface roughness and optimizing the opening ratio and aspect ratio of the microcavities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods (semiconductor photolithography combined with electrolytic etching or nanoimprint technology) are used to form microcavities, then the microcavities can be formed in the wavelength selective heat radiation material, but the upper portion of the cavity wall becomes chipped or thin-walled, resulting in reduced emissivity and inability to selectively radiate heat radiation light at the designed emissivity
Solution Approach 1:
The patent changes the etching parameters by using inductively coupled plasma (ICP) etching instead of conventional electrolytic etching or nanoimprint methods. By adjusting the etching gas composition (CF4/O2 mixture), power (1300W), pressure (5Pa), and other parameters, the patent achieves clean etching without chipping or thin-walling of the cavity walls, maintaining the designed emissivity performance while forming precise microcavities with 3μm opening size and 10μm depth
Solution Approach 2:
The patent replaces the mechanical contact-based nanoimprint method and chemistry-based electrolytic etching with a plasma-based physical-chemical etching process. This substitution eliminates the mechanical contact that causes chipping and the chemical reactions that cause thin-walling, achieving clean cavity formation with controlled morphology and high emissivity performance
2Reliability
If the aspect ratio of microcavities is increased to enhance selective radiation intensity, then the radiation characteristic improves, but the formation of microcavities becomes extremely difficult with conventional methods
Solution Approach 1:
The patent achieves high aspect ratio (3.3) microcavities by optimizing plasma etching parameters including high power (1300W), specific gas composition (CF4/O2), and controlled pressure (5Pa). These parameter changes enable the formation of deep, narrow cavities with clean walls that maintain structural integrity, achieving both high selective radiation intensity and manufacturability
Solution Approach 2:
The patent employs a two-stage periodic etching process: first forming cavities with one set of parameters, then adjusting parameters for final cavity refinement. This periodic adjustment of etching conditions enables precise control over cavity depth and shape, achieving high aspect ratios while maintaining manufacturing feasibility
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 approach results in a wavelength selective heat radiation material with high emissivity (0.85 or more) in the infrared ray transmission wavelength region, enhancing heat radiation efficiency and selectively radiating heat energy from the heat generation source to the resin member.
Implementation Method 1
it can be prevented that upon the transcribing for the mask, entering of air between the metal foil and the mask hinders the transcription of the pattern. In addition, since adhesiveness of the mask is enhanced
Implementation Method 2
by employing a first method for manufacturing a wavelength selective heat radiation material, the method including the steps of: (a) placing a mask having predetermined openings on one surface of a base material and causing the mask to tightly adhere to the one surface; (b) etching the base material at the openings of the mask and forming microcavities in the base material
Data Source
AI summary
An object is to provide a method for manufacturing a wavelength selective heat radiation material in which a surface roughness of an upper portion of a cavity wall defining each microcavity is suppressed or in which microcavities each having an aspect ratio larger than 3.0 are formed. For the wavelength selective heat radiation material, a base material having a mask having predetermined openings tightly adhered to a surface thereof, or a base material in which depressions are previously formed on one surface thereof by pressing a die having projections arrayed so as to correspond to positions of microcavities thereagainst, is subjected to anisotropic etching, thereby providing a wavelength selective heat radiation material in which the surface roughness of the upper portion of the cavity wall defining each of the microcavities is suppressed or a wavelength selective heat radiation material having microcavities whose each aspect ratio is larger than 3.0.