Study on the relationship between unevenness perception and fingertip characteristics measurement by using optical coherence tomography

• Published in: Surface topography metrology and properties Vol. 13; no. 3; pp. 35005 - 35015
• Main Authors: Harada, Takuya, Okuyama, Takeshi, Tanaka, Mami
• Format: Journal Article
• Language: English
• Published: IOP Publishing 30.09.2025
• Subjects: finger pad; grooved plate; mechanical properties; optical coherence tomography; papillary layer
• ISSN: 2051-672X; 2051-672X
• DOI: 10.1088/2051-672X/adec09

This study aims to elucidate the relationship between the mechanical properties and deformation behavior of the fingertip skin during tactile motion. For this purpose, a fingertip skin measurement system using optical coherence tomography(OCT) was developed. Using this system, OCT images were obtained during passive stroking on a glass plate, and deformation of the fingertip epidermis was analyzed. From the analysis results, the shear elastic modulus of the epidermis was calculated from the measured shear deformation, revealing individual differences among 10 subjects. Next, OCT images were obtained during passive stroking on an acrylic plate with a groove, and the deformation behavior of the epidermis was analyzed using the digital image correlation(DIC) method. Shear strain distributions of the epidermis were obtained, and it was confirmed that the deeper groove caused greater shear strain compared to flat surfaces. Stroking speed was found to influence shear strain significantly. Also, subjects with lower shear elastic modulus show greater shear strain variability under different stroking conditions. Those with lower shear elastic modulus tend to be more sensitive to such differences. These findings indicate that shear strain in the epidermis and the shear elastic modulus are key factors influencing the deformation behavior of the epidermis during tactile motion.