Laser wavelength and eye damage;
In the laser injury, the eye injury of the body is the most serious. For lasers with wavelengths in visible light and near infrared light, the refractive medium of the eye has low absorption rate and high transmittance, while the refractive medium has strong focusing ability. When high-intensity visible light or near-infrared light enters the eye, it can pass through the refractive medium of the human eye and accumulate light on the retina. At this time, the laser energy density and power density on the retina increased to thousands or even tens of thousands of times, and a large amount of light energy was instantly concentrated on the retina, which caused the temperature of the photosensitive layer of the retina to rise rapidly, causing the photosensitive cells to solidify, denature and die, losing their photosensitive function. When the laser is focused on the photosensitive cells, protein solidification and denaturation caused by overheating are irreversible damage. Once damaged, it will cause permanent blindness in the eyes. Different wavelengths of laser have different effects on the eyeball, and their consequences are also different. The damage of far-infrared laser to eyes is mainly caused by cornea, because almost all the laser at this wavelength is absorbed by cornea, so the damage to cornea is the most serious, mainly causing keratitis and conjunctivitis. Patients feel eye pain, foreign body-like stimulation, fear of light, tears, eyeball congestion, decreased vision and so on. When far infrared rays are damaged, it should be covered to protect the injured eyes, prevent infection and treat symptoms. The damage of ultraviolet laser to eyes is mainly cornea and lens. The ultraviolet laser in this band is almost completely absorbed by the lens of the eye, while at a long distance, it is mainly absorbed by the cornea, which will cause lens and cornea opacity.
Laser damage to skin:
Because of its physiological structure, human skin has sensitive functions such as touch, pain and temperature, which constitutes a complete protective layer. Moreover, the skin is composed of multiple tissue layers, and each layer has different cells. When laser irradiates the skin, if its energy (power) is too large, it will cause skin damage. Of course, the lesion can be repaired by tissue. Although the function is reduced, it does not affect the overall functional structure, and the damage to the eyes is much lighter. But we must also attach great importance to it. The threshold of laser damage to skin is also very high, and the output energy of various lasers is very different. At present, high-power lasers are widely used. The damage degree of laser to skin is related to laser irradiation dose, laser wavelength, skin color depth, tissue moisture and skin stratum corneum thickness, among which the first three factors are the main ones.
Laser dose and skin damage degree:
After a lot of practice, the greater the laser power density (or energy density) used when irradiating the skin, the greater the damage to the skin, and there is a positive correlation between them. After the skin absorbs the laser energy exceeding the safe threshold, the skin in the irradiated area will appear thermal erythema, blisters, coagulation, thermal carbonization, boiling, combustion and thermal vaporization in turn with the increase of dose. Therefore, the mechanism of laser damage to skin is mainly caused by the thermal effect of laser. After the skin absorbs laser energy, the local skin temperature rises in a short time, and the damage caused by different degrees of temperature rise is also different. Especially for infrared laser bursts, such as CO2 laser (steam laser), the skin has high absorption rate and low transmittance for this infrared laser with the wavelength of 10.6μm, and the skin absorbs CO2 laser strongly, which makes the local temperature of the skin rise rapidly and easily causes damage. The severity of laser damage to skin is determined by the skin's absorption rate of laser, and the skin's absorption rate of laser is determined by the wavelength of laser. The higher the absorption rate of skin to a certain wavelength laser, the more serious the damage. For example, when the absorption rate of ultraviolet laser and infrared laser is high, these two kinds of lasers are the main wavelength lasers that damage the skin.
The main effect of infrared laser on skin is thermal burn. When this kind of laser irradiates the skin, the power is relatively small, causing telangiectasia and skin redness and fever. With the increase of laser power density, the degree of thermal damage also increases. On the contrary, the effect of ultraviolet laser on skin is mainly light. When ultraviolet laser irradiates the skin, it can cause skin erythema and aging, and when it is excessive, it will cause serious carcinogenesis. The ultraviolet wave that is most harmful to the skin is at 270 ~ 290 nm, and the wavelength is greater or less than 270 ~ 290 nm, so the damage degree is relatively light.
YAG infrared laser, wavelength 1.064um, little harm to skin.
At present, the main lasers of Australia-China laser are:
Solid-state laser (infrared band 1064nm): series of solid-state laser marking machines, lamp-pumped YAG marking machines, DP semiconductor-pumped marking machines, optical fiber marking machines, lamp-pumped YAG marking machines, DP semiconductor-pumped marking machines, EP semiconductor-pumped marking machines, fiber laser marking machine, keyboard marking machines, bearing marking machines, PCB marking machines, wafer marking machines and laser molds. Automatic laser welding machine, laser spot welding machine, optical fiber transmission laser welding machine, sensor welding machine, lamp pump YAG high-precision cutting and punching machine, laser resistor regulator, laser dicing machine, laser stripper (YAG).
It has its own eye protection design or high-speed electronic filtering system, and adopts advanced anti-laser flicker technology (this technology is only owned by a few companies). For example, long-term direct observation of laser, it is recommended to wear anti-laser eyes.
Solid-state laser (green belt: 532nm): Laser dicing machine and high-precision cutting punch are recommended to wear anti-laser eyes if the laser is observed directly for a long time.
Gas laser (infrared band 10.64um): CO2 marking engraving machine series, button marking machine, label marking machine, glass marking machine, CO2 laser cutting machine, etc. This type of laser is very harmful to the skin, so users must be careful not to touch the laser.
Aohua laser belongs to the fourth class of laser devices (class 4 lasers). Any operation, use or adjustment that does not conform to the operating procedures may cause users to be exposed to harmful radiation. Laser burn: If the user's hands or fingers are directly or indirectly irradiated by laser, the wound is similar to "normal high fever". Although the burn caused by laser pulse is harmless, attention should be paid to avoid infection and disinfect the wound. If the situation is serious, please go to the hospital for treatment. Wish you good health.