The most popular cosmetic treatments involving irradiation of the skin with optical energy are hair removal, and the removal of vascular and pigmented lesions. These treatments are based on selective light absorption by the target in comparison to the surrounding skin tissue so as to heat the target to a temperature that is sufficiently high to cause thermal destruction of the target without raising the surrounding skin to damaging levels. Two types of devices are common in these treatments: one uses laser radiation, while the other uses filtered light from a light source. U.S. Pat. No. 5,405,368 describes a device for skin treatment comprising an incoherent light source. U.S. Pat. No. 5,669,916 describes use of a laser for hair removal. The main limitation of these methods is the high absorption of optical energy by the epidermis and the attenuation of the energy with increasing penetration depth due to light absorption and scattering.
USPTO Backgrounds
USPTO Backgrounds