Why Wear Laser Goggles? What Does The Od Value On The Laser Goggles Mean?
Lasers are light amplifications (light amplification by stimula?ted emissions of radiation, LASER), hence the name laser. It is an artificial, special type of non-ionizing radiation, with high brightness, direction and good co-location and other excellent characteristics. It is widely used in industry, agriculture, national defense, medical research and scientific research. Lasers consist of working substances, optical resonance cavities and excitation energy. Lasers are divided into solid, liquid and gas lasers according to the physical state of the substances they work on. According to the emission spectrum, it is divided into infrared, visible light, ultraviolet laser and X and 7-ray lasers which have been developed in recent years. Because of the different laser output methods, there are continuous wave lasers, pulse wave lasers, as well as long pulses, giant pulses and ultra-short pulse lasers.
The use of lasers includes laser punching, cutting, welding, etc. in industry. in the military and aerospace industry for lidar, laser communications, laser ranging, laser guidance, laser aiming and so on; medically used in ophthalmology, surgery, dermatology, oncology and other diseases of the treatment; in the life sciences, nuclear physics and other fields of research, there are also widely used. the interaction between laser and biological tissue is mainly manifested in thermal effect, photochemical effect, mechanical pressure effect and electromagnetic field effect. the damage and damage of laser to human tissue are mainly determined by the wavelength, light source type, emission mode, incident angle, radiation intensity, exposure time and the characteristics of biological tissue and spot size. laser damage to the human body’s target organs are mainly the eyes and skin.
When the eye is in a horizontal laser beam, the exposure intensity of the retina is 200,000 times greater than that of the cornea. visible light and short-wave infrared radiation are commonly referred to as light radiation retinal damage bands, because these bands of light beam can be highly focused in the retina, and mostly located in the central cctv area of the macula. most lasers currently emit the most harmful lasers in visible light bands below 500nm. the typical manifestations of injury are edema, congestion, bleeding, so that the retina shift, perforation, and finally lead to the formation of central blind spots and scars, vision sharply decreased. for burns on the edge of the retina, there is generally no subjective feeling, because such burns are painless and prone to neglect. 460nm of blue light can cause the permanent disappearance of retina conical cells, known as “blue light damage”, the main symptom of dizziness. in the event of chromophotogenic loss, at least one or more conical cell groups are damaged.
Laser damage to the skin is mainly caused by thermal effects. mild damage is characterized by erythema and pigmentation. as the amount of exposure increases, blisters can appear and skin fades, coking and ulcers form. 250-320nm ultraviolet laser, can make the skin to produce photosensitive effects. when exposed to high-power laser radiation, deep organs can also be damaged through the skin.
after exposure to the light in addition to rapid separation, should be kept quiet, full rest, eye protection. for bleeding and oozing, vitamins, energy preparations can be used and, if necessary, glucocorticoids. it can also be treated with chinese medicine for live blood, syringes and swelling. laser protection includes lasers, working environment and individual protection. lasers must have safety facilities, where the beam may leak, should be set up anti-light closed cover. install a laser-on and beam-stop chain. studio enclosure structure is made of absorbent material, the tone should be dark. the work area should be well lit. there must be no appliances or objects that reflect or refract the beam in the room.
OD-Optical Density, the number represents the pass rate, and OD4 represents the pass rate of one in 10,000.
Laser travels in one direction, with good monochrome, strong direction, high brightness and so on. Because of the brightness of the laser, a small-power laser produces about the same amount of energy as sunlight. In human organs, the eyes are most vulnerable to laser damage due to the focusing effect of the human eye. Visible light (400-700nm) and near-infrared light (IR-A, 700-1400nm) can penetrate the eyes, causing irreversible damage to the retina, optic nerves and the center of the eye 80-400nm) can damage corneas and crystals, and mid-infrared (IR-B, 1400-3000 nm) can penetrate the surface of the eye, causing cataracts, while far infrared (IR-C, 3000 nm-1). mm) will hurt the outer surface of the eye and cornea, burning the retina, resulting in vision loss or even blindness;
secondary beams are located in or near the working area, and these beams are derived from the reflection of the main beam on various surfaces, and the secondary beam at different angles is equally strong enough to cause damage to the eye the greater the damage, the smaller the incident angle, the smaller the spot of light that is imaged on the retina, the more concentrated the energy density is, and the more likely it is to cause retinal damage at night than during the day, as the pupil expands at night and is exposed to laser radiation of the same energy density, the retina receives more laser energy. according to the wavelength, output power and beam characteristics of the laser, the safety level of the laser equipment is divided from 1 to 4 categories. the higher the value, the greater the potential hazard of the laser system.