A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation

ISO standards exist for evaluating sunscreens, such as those based on visual inspection. This assessment yields subjective results and is thus unreliable. Therefore, to verify the results of the visual assessment of sunscreens, quantitative evaluation methods are necessary. These methods require the...

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Main Authors: Kae Nakamura, Takahiro Kono, Uma Maheswari Rajagopalan, Jun Yamada
Format: Article
Language:English
Published: MDPI AG 2022-11-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/12/22/11521
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author Kae Nakamura
Takahiro Kono
Uma Maheswari Rajagopalan
Jun Yamada
author_facet Kae Nakamura
Takahiro Kono
Uma Maheswari Rajagopalan
Jun Yamada
author_sort Kae Nakamura
collection DOAJ
description ISO standards exist for evaluating sunscreens, such as those based on visual inspection. This assessment yields subjective results and is thus unreliable. Therefore, to verify the results of the visual assessment of sunscreens, quantitative evaluation methods are necessary. These methods require the measurement of the total radiation energy that is diffusely transmitted in all directions. For the measurements, although an integrating sphere is widely used to measure diffusely transmitted radiation, a simpler measurement would contribute to the easy usage of quantitative and objective evaluation. We propose the use of fluorescent materials as an alternative method to characterize sunscreens. In this method, a layer containing a fluorescent material is placed behind the sunscreen, and when the excitation radiation transmitted through the sunscreen reaches the fluorescent layer, it emits fluorescence. The feasibility of this measurement method was evaluated through numerical analysis and it demonstrated that hemispheric transmittance can be measured when the fluorescent layer is of high concentration or thick. Additionally, a prototype fluorescent layer was fabricated, and also the results were compared with the amount of diffusely transmitted UV from several commercial sunscreens. This pilot evaluation measurement method showed that the UV shielding index shown on the package does not necessarily truly reflect the amount of UV energy transmitted through the sunscreen, thus failing to provide the expected protection.
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spelling doaj.art-84a930442ae04913ae7b2162f89e7db82023-11-24T07:36:42ZengMDPI AGApplied Sciences2076-34172022-11-0112221152110.3390/app122211521A Novel Fluorescent-Material-Based Simple Method for Sunscreen EvaluationKae Nakamura0Takahiro Kono1Uma Maheswari Rajagopalan2Jun Yamada3Department of Precision Machinery Engineering, College of Science and Technology, Nihon University, 7-24-1 Narashinodai, Funabashi-shi, Chiba 274-8501, JapanDepartment of Mechanical Engineering, College of Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, JapanDepartment of Mechanical Engineering, College of Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, JapanDepartment of Mechanical Engineering, College of Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, JapanISO standards exist for evaluating sunscreens, such as those based on visual inspection. This assessment yields subjective results and is thus unreliable. Therefore, to verify the results of the visual assessment of sunscreens, quantitative evaluation methods are necessary. These methods require the measurement of the total radiation energy that is diffusely transmitted in all directions. For the measurements, although an integrating sphere is widely used to measure diffusely transmitted radiation, a simpler measurement would contribute to the easy usage of quantitative and objective evaluation. We propose the use of fluorescent materials as an alternative method to characterize sunscreens. In this method, a layer containing a fluorescent material is placed behind the sunscreen, and when the excitation radiation transmitted through the sunscreen reaches the fluorescent layer, it emits fluorescence. The feasibility of this measurement method was evaluated through numerical analysis and it demonstrated that hemispheric transmittance can be measured when the fluorescent layer is of high concentration or thick. Additionally, a prototype fluorescent layer was fabricated, and also the results were compared with the amount of diffusely transmitted UV from several commercial sunscreens. This pilot evaluation measurement method showed that the UV shielding index shown on the package does not necessarily truly reflect the amount of UV energy transmitted through the sunscreen, thus failing to provide the expected protection.https://www.mdpi.com/2076-3417/12/22/11521sunscreensUV rayshemispherical transmittanceintegrating spherefluorescent material
spellingShingle Kae Nakamura
Takahiro Kono
Uma Maheswari Rajagopalan
Jun Yamada
A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
Applied Sciences
sunscreens
UV rays
hemispherical transmittance
integrating sphere
fluorescent material
title A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
title_full A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
title_fullStr A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
title_full_unstemmed A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
title_short A Novel Fluorescent-Material-Based Simple Method for Sunscreen Evaluation
title_sort novel fluorescent material based simple method for sunscreen evaluation
topic sunscreens
UV rays
hemispherical transmittance
integrating sphere
fluorescent material
url https://www.mdpi.com/2076-3417/12/22/11521
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