Since the 1990s, with the advancement of science and the development of laser technology, new types of cosmetic laser machines have been emerging, and have achieved very significant achievements: in the middle and late 1990s, long-pulse ruby laser, alexandrite laser, Nd: YAG laser and The emergence of semiconductor lasers has made laser hair removal technology increasingly mature. Advanced complete sets of laser hair removal instruments from the United States, Israel, the United Kingdom, Germany and Japan have flooded into other countries and become more and more popular. At the same time, laser hair removal equipment has also gained more and more in the world. The more applications and recognition, the more promising its prospects are. The medical beauty laser hair removal equipment market has huge laser beauty consumption capacity and consumption potential, and the development of the medical beauty equipment market will surpass that of Europe and the United States in the next few years, and there will be more applications for facial beauty and hair removal. In response to this situation, portable home laser beauty equipment (such as for hair removal, wrinkle removal, etc.) is expected to become a major development trend in the future.
How laser hair removal equipment works:
The pulse duration (or pulse width, pulse width for short) should be less than or equal to the thermal relaxation time (TRT) of the target tissue. The pulse duration of the laser must be long enough to cause sufficient damage to the target tissue, but the amount of heat conduction is proportional to the pulse duration of the laser. The longer the time, the greater the scope of thermal damage. Just like the phenomenon that people often encounter in daily life, if you touch a hot pot with your fingers quickly, the skin will not be scalded, but if the contact time is a little longer, the skin will be burned. According to optical theory, as long as the pulse duration of the laser is less than or equal to the thermal relaxation time of the target tissue, it will not cause thermal damage to the surrounding tissue. Thermal relaxation time is the time it takes for a heated tissue to reduce its own heat by 50% through thermal diffusion. This parameter is an index to measure the heat conduction speed of the target tissue. We now know that the volume of hair follicles is large, and its TRT is several milliseconds to one hundred milliseconds, so the pulse width of the laser required for hair removal is preferably between several milliseconds and one hundred milliseconds. The biggest difference between modern laser hair removal equipment and more than 10 years ago is the precise control of pulse width, which is the fundamental guarantee for the safety of modern laser treatment.
At present, the more common semiconductor laser hair removal uses near-infrared light with wavelengths of 808nm and 810nm. This wavelength of laser can effectively penetrate the skin and reach the depth of the target tissue (melanin). According to the theory of selective photothermal action of melanin, the appropriate adjustment is made. The pulse duration is sufficient to ensure that the target tissue absorbs enough energy to damage the target tissue in the form of thermal energy through energy conversion. Therefore, after the target cells absorb the energy of light, the temperature rises sharply, which leads to the destruction of the surrounding hair follicle tissue, and the hair is removed. Appropriate energy density guarantees sufficient thermal damage to destroy the target tissue within a suitable pulse duration, while the surrounding tissue does not contain pigment, does not absorb energy, has no thermal energy conversion, and is hardly affected by thermal damage, thus ensuring the safety of treatment. Semiconductor laser hair removal is especially suitable for people with yellow skin. Usually the pulse width is 5~1000ms, the energy density is 5~100J/cm², and the light spot is 2~14mm.
The laser wavelength of alexandrite laser is 755nm, which is also a commonly used hair removal laser. Usually the pulse width is 0.5~1000ms, the energy density is 5~100J/cm², and the light spot is 3~15mm.
Long pulse width Nd:YAG laser hair removal effect is also very good, especially for black shaggy hair removal, especially suitable for patients with darker skin. Usually the pulse width is 0.25~1000ms, the energy density is 10~600J/cm², and the spot is 3~18mm
Laser hair removal equipment factory designs stack or multi-single tube 808nm lasers, 755nm lasers with Alexandrite (Alexandrite) crystal as the core laser working material, long pulse width Nd:YAG lasers, etc., and can customize other wavelengths for the needs of different colors of hair. The core laser for desktop and household handheld hair removal products.
