The Research Of Pigment Of Skin Tissues Acted By Semiconductor Laser

With high efficiency,small size,light size,low price and long working life,the semiconductor laser has played more and more important role in the application of bio-medical treatment,such as clinical application of laser medicine in ophthalmology,dermatology and otolaryngology.However,the application of semiconductor lasers in the treatment of pigmented skin diseases is less and is in the preliminary stage of development.Thus making it great significance to study the influence of semiconductor laser on pigment content in skin tissue.The first part of the thesis introduces the interaction mechanism between laser and biological tissue,including the optical properties of biological tissues and the types of laser biological effects.And the thermal effect on biological tissue and the influence mechanism of photothermal effect on pigment particles are well analyzed.In the second part of the article,based on the theory of selective solar-thermal requirement for laser parameter,and reference to other types of lasers used in the treatment of pigment-diseased skin tissue of laser parameters,with the using of MCU for the control module,and the principle of voltage-controlled constant current source,a prototype of semiconductor laser experiment systems is designed and assembled.For the last part of this thesis,the experiment of interaction between laser and pigmented skin are conducted with the using of the semiconductor laser experiment system.To illustrate the effect of the experiment,an optical fiber spectrometer provided by Avantes is adopted to measure the reflectance of the skin tissue before and after the action.The semiconductor laser experiment system is stable and can achieve precise control of output laser power and time.The experimental results showed that the laser with wavelength 560~590nm,pulse width 3~5ms and power density of 15~25J/cm2,have good performance in application of reducing pigment.After 1~3 times(an average of 5 times)of treatments,the spectral reflectance of pigmented skin can be improved by 30%,at least.It has been proved that the pigment granules in the tissue of the skin can be reduced by semiconductor laser with suitable laser parameters.