IEC 60747-5-14:2022（E）规定了基于热反射（TR）法的单个LED管芯或封装表面温度的测量方法。TR是光的反射率随物质温度变化的效应。本部分测量了沉积在冶金pn结附近的金属膜反射光的相对变化，以及LED结温度的相对变化。当金属表面和pn结之间的热阻效应很小时，表面温度可以近似为结温度。

IEC 60747-5-14:2022(E) specifies the measuring method of the surface temperature of single LED die or package, based on the thermoreflectance (TR) method. TR is the effect that the reflectance of light changes with the temperature of a substance. This part measures relative change in the reflectance of light from a metal film deposited nearby on the metallurgical pn junction as the relative change in the LED junction temperature. The surface temperature can be approximated as the junction temperature when the thermal resistance effect between the metal surface and the pn junction is negligibly small.