Skin Barrier Function Calculation Using AC Signal Phase Angle

The patent applies parameter changes by introducing a phase angle parameter (θ) derived from delay time measurements using AC signals. This parameter transformation enables accurate representation of skin barrier function across diverse skin conditions. The phase angle serves as a transformed parameter that captures the electrical characteristics of skin tissue, allowing consistent measurement from normal to rough skin conditions where conventional methods fail.

The patent applies preliminary action by pre-determining constants through regression analysis between the phase angle parameter and reference measurements (TEWL or stratum corneum thickness). These constants are established beforehand and stored for subsequent use. During actual skin barrier function measurements, the pre-determined constants are applied directly to calculate results, eliminating the need to perform complex regression analysis in real-time and thus reducing operational complexity while maintaining high precision.

The patent applies the intermediary principle by using an AC signal as a mediator to probe skin tissue characteristics. The AC signal interacts with the skin's electrical properties, and the resulting delay time provides information about skin barrier function. This intermediary approach enables measurement across wide ranges of skin conditions without requiring direct physical contact or complex mechanical measurement systems, thereby reducing measurement difficulty while expanding applicability.