Patch sheet for skin, method for using same, ultraviolet sensing method, and method for evaluating ultraviolet protection performance

A skin-attaching sheet comprising an attaching portion configured for attaching to skin,

• wherein the attaching portion comprises a color-changeable layer that changes color following exposure to ultraviolet rays, and
• wherein the attaching portion has a color difference (ΔE*ab) in an L*a*b* color system between before the exposure to ultraviolet rays and 10 seconds after the exposure to ultraviolet rays of 5 or more and 300 or less in a standard exposure test in which the attaching portion is exposed to ultraviolet rays under the following conditions in a moist state:
• moist condition:
• 5 mg/cm of water is applied on the attaching portion, and the attaching portion is left to stand for 5 minutes to moisten;
• wavelength range:
• 280 nm to 400 nm;
• exposure time:
• 10 seconds;
• and
• ultraviolet intensity:
• 1.2 mW/cm2;
• wherein the color-changeable layer contains a photochromic compound, and wherein the photochromic compound is one or more selected from a spiropyran compound, a spirooxazine compound, a bipyridine compound, a fulgide compound, a chromene compound, and derivatives thereof.