Study On Nearinfrared High-power Semiconductor Laser Therapeutic Machine And Its Application

The generation and development of laser technology not only breaks a new path to investigate the science of life, but also provides new means for clinical diagnosis and treatment of disease. It brings new opportunity and vitality for the biomedical technology research, and has been used widely in the medical field. The semiconductor laser is especially suitable for the medical equipment manufacturing because of its characteristic, such as wide range of wavelength, small body, light weight, high efficiency and long life span, as well as can be fiber coupled. The clinical application of semiconductor laser almost covers other kinds of lasers’applied range. In the recent year, the semicondcutor laser technology is developing rapidly, and its market share is increasing continuously. Thus it has broad prospects for development.This paper mainly concerns the R&D of each part of the medical laser device, including the fiber coupling module based on single emitters, high-power laser driver, control systems and laser transport systems. Furthermore, the photo-thermal inter -action between laser and tissue is analyzed, and the efficiency and mechanism of skin welding using near-infrared diode laser is investigated.The beam coupling technology based on single emitters is developing in the recent years, and the method is to couple the collimated output beam of several diode lasers to the same optical path and then to a single fiber. Semiconductor laser module based on this technology is particularly suitable to be used as the therapeutic laser of medical device because of its excellencies such as simple cooling, low driving-current, long life span, high brightness, etc. In this paper, according to the optical and mechanical design, fiber coupling modules based on single emitters providing 30 Watts output power from 200 micron 0.2 NA fibers with wavelengths of 808nm and 980nm respective are made, which are used as therapeutic laser beam for clinical application.A constant-current supply power using BatMod module, which has the excellences of high-reliability, high-efficiency and miniaturization, is used for driving the fiber coupling modules of the medical laser devices. The control system which controls the set and output of laser parameters accurately is based on the ARM microprocessor. A temperature feedback and control system is employed to obtain a real-time monitoring and control the temperature of the diode lasers and driver. The touch screen control panel, including multiple functional modules, is used to improve the humanity of the interfaces.Skin welding with a combination of 1064 nm and 980 nm diode lasers, which’s first-time in the literature, is performed in this paper. The long-time effect of laser skin welding is investigated through macroscopic & microscopic examinations as well as tensile strength tests at different times after the welding, in comparison with that of conventional suturing or welding with single laser. It’s found that laser tissue welding with a combination of two near-infrared lasers (980nm and 1064nm) yields more effective closure and healing than conventional suturing technique or welding with single laser (980nm or 1064nm) with faster recovery, better apposition of tissue, less tissue interaction and tighter closure. It is an effective method for wound closure, and further investigations are in progress for clinical use.This paper is composed of seven chapters. The first chapter is devoted to the development status of high-power diode lasers and medical laser machines. And the second chapter is devoted to the optical and thermal properties of the high power diode lasers. The beam coupling methods of high power diode laser are expatiated in the third chapter, and the design of beam coupling structure based on single emitters is presented, as well as the results and analysis of coupled experiment. The photo-thermal interaction between laser and tissue is summarizes in the fourth chapter. The fifth chapter describes the overall design of the high-power medical laser device detailedly, so well as its performance. The efficiency of skin welding with near-infrared diode lasers is investigated in the sixth chapter. The final Chapter is summary and expectation.