IPL filter (Intense Pulsed Light Filter) is an optical filter specifically designed for IPL devices. Its core function is to selectively allow light within a specific wavelength range to pass through while blocking short-wavelength intense light (especially ultraviolet and short-wave visible light), in order to meet the safety and efficacy requirements in medical aesthetics and skin treatment fields. IPL filters are typically made using dielectric film coating technology or colored glass materials. They precisely define the light transmission band based on the treatment goal (such as hair removal, skin whitening, and skin rejuvenation), and block short-wave harmful light through a high cutoff rate (OD ≥ 4).