TAILIEUCHUNG - Energy focusing efficiency estimation of a multi level Fresnel lens through surface profile

A high focusing efficiency of a multi-level Fresnel lens is desired when it is designed and manufactured. How to determine the focusing efficiency becomes a problem after the Fresnel lens is fabricated. A method to estimate the focusing efficiency of the Fresnel lens basing on its surface profile is proposed. | Journal of Science & Technology 130 (2018) 007-012 Energy Focusing Efficiency Estimation of a Multi-Level Fresnel Lens Through Surface Profile Tuan-Anh Bui * Hanoi University of Science and Technology – No. 1, Dai Co Viet Str., Hai Ba Trung, Ha Noi, Viet Nam Received: January 02, 2018; Accepted: November 26, 2018 Abstract A high focusing efficiency of a multi-level Fresnel lens is desired when it is designed and manufactured. How to determine the focusing efficiency becomes a problem after the Fresnel lens is fabricated. A method to estimate the focusing efficiency of the Fresnel lens basing on its surface profile is proposed. Hence, the profile of Fresnel lens fabricated shows how similar with the profile designed, which has been theoretically predicted a maximal focusing efficiency such as and 81% for a two-phase and four-phase level Fresnel lenses, respectively. This calculation method can be applied to estimate the focusing efficiency of any surface profile of Fresnel lenses fabricated without a direct measurement of focusing efficiency. The focusing efficiency of a four-phase level Fresnel lens designed to operate at a frequency of 100 MHz of an ultrasonic ejector, which was fabricated by a two-mask process using SU-8 photoresist, approximate 60% is illustrated. Keywords: Fresnel lens, ultrasonic, energy focusing efficiency. 1. Introduction* Fabrication of two- and four-phase level Fresnel lenses with an operation frequency of 1 and 170 MHz, and measurement of focusing efficiency was presented. They showed that focusing efficiencies of 170 MHz two- and four-phase level Fresnel lenses are close to the theoretical values, which are about 40 and 80%, respectively. Meanwhile, the focusing efficiency of 1 MHz 4 phase Fresnel lens is significantly better than the 2 phase lens due to it can reach the theoretically predicted value of 80% [5]. [10] proposed a finite element analysis of multilevel acoustic Fresnel lens. They indicated that a high focusing .

• Điện - Điện tử
• Fresnel lens
• Energy focusing efficiency
• Fabrication process of Fresnel lens
• Multi level Fresnel lens
• Surface profile
• Application of geometrical tolerances
• Profile tolerance of a surface
• Circular run out
• Total run out
• Profile tolerance of a line
• Characteristics on engineering drawings
• Journal of Science and Technology
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• Vietnam Journal of Science and Technology
• Bài viết khoa học
• Tạp chí Khoa học Công nghệ Việt Nam
• Profile grinding
• Surface roughness
• Cutting parameters
• Surface wounds
• Antibiotic resistance
• Microbiological profile
• Antimicrobial susceptibility pattern
• Peripheral tertiary care hospital
• Radiation measurements
• Infrared photoluminescence
• Infrared stimulated luminescence
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• education teachers
• financial resources
• reflect disparities
• individual resources
• privileged backgrounds
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• Wave structure interaction
• Wave hydrodynamics
• Water surface profile
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• BMC Cancer
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