New trends in the development of semiconductor laser hair removal technology

New trends in the development of semiconductor laser hair removal technology

Dr. R. Rox Anderson and John A. Parrish from the United States proposed the selective photothermal theory in the early 1980s: according to the biological characteristics of different tissues, as long as the appropriate laser parameters (wavelength, pulse duration, energy), which can ensure the most effective treatment of the diseased part while minimizing the damage to the surrounding normal tissue. At the same time, Dr. Anderson and Parrish led the industry to draw a wavelength absorption map of the target tissue based on this theory (see Figure 1), which provides guidelines for the use of light to achieve the curative effect of medical cosmetology.

Among the many applications of selective photothermal theory, the use of laser hair removal treatment is undoubtedly one of the most fruitful applications. The wavelength of the laser is precise and has stronger energy expansion. Doctors can use the laser with the appropriate wavelength, appropriate energy density and pulse width to achieve hair removal according to the patient’s skin color, hair color, pain perception, etc.

With the continuous progress of laser hair removal technology and people’s pursuit of beauty and experience, people are no longer satisfied with the basic appeal of hair removal, but have transformed into the pursuit of a safer, more comfortable, more effective and more efficient hair removal experience. This puts forward higher requirements for laser hair removal technology, and also promotes new developments in this technology.

How to translate the more comfortable, more effective and more efficient treatment experience pursued by end users into requirements for equipment, and how to translate these requirements into design language into product design, requires product development and designers to refer to the following The formula is used for product development, and this formula is also the design guideline for optoelectronic medical and aesthetic equipment. At the same time, how to balance the selection of each indicator in the following formula, so that the developed equipment can better meet the needs of future end users and more in line with the development trend of the terminal market, has also become one of the core competitiveness of medical beauty equipment manufacturers.

Energy density = peak power X pulse width / spot area

For laser hair removal applications, energy density means effect. In theory, higher energy density will bring better treatment effect; and peak power is related to cost. The higher the peak power, the higher the cost of the corresponding laser. ; The spot area is related to the treatment efficiency. For small treatment areas such as armpits and lip circumference, the output of smaller spot area will not bring about low treatment efficiency, but for large treatment areas such as legs and back In other words, the larger the spot area, the higher the treatment efficiency. The pulse width is related to comfort and effect. The shorter the pulse width, the more comfortable the treatment process is. At the same time, when the pulse width is within 10~30ms, the treatment effect will also be improved. better.

It is this higher and higher requirement for terminal experience that has promoted the transformation of beauty equipment manufacturers’ concept of instrument design, and has also formed a new trend in laser hair removal technology.

In recent years, the mainstream power of semiconductor lasers used for laser hair removal has experienced an increase from 300W to 600W, and is rapidly changing to a power above 1200W, which is one of the recognized trends in the industry. Why is there such a shift? The root cause is still reflected in the end user’s demand for a more effective and comfortable treatment experience.

According to the above energy density formula, on the premise that the energy density (effect) and the spot area (efficiency) remain unchanged, the higher the peak power, the narrower the pulse width can be compressed. On the other hand, the narrow pulse and broad band bring better clinical effects and a more comfortable clinical experience.