Reflective filter Absorption filters use the lens to absorb certain wavelengths of light to reduce the intensity of the light entering the eye, but because the lens absorbs some light, it becomes heat and emits, especially infrared and other longer waves. Due to the accumulation of heat generated by the light, the eyes feel very uncomfortable. If a reflective filter is used, this problem can be solved well. As mentioned in the previous coated glasses, if the surface of the lens is coated with a layer of material with a higher refractive index than the lens itself, it will increase the reflection of light and reduce the intensity of light transmission, so that it can protect The eyes are not harmed by strong light and harmful rays. In actual work and life, in many cases, the absorption type and the reflection type are used in combination, that is, a layer of high reflection film is plated on the colored lens to make the filtering effect stronger, such as electric welding, chlorine arc welding, plasma cutting and other operators. Wearing glasses, you can use this method to solve.
Sun-shading glasses, also known as sunglasses, have a visible light transmittance of about 20%, and absorb ultraviolet and infrared rays well. There are light green, light gray, light tea and other colors, used to make sun-shading and snow work protective glasses. Among them, light gray lenses have the least effect on color recognition; light tea glasses make the blue sky look darker and reduce the transmission of green light; light green lenses reduce the transmission of red light.
The colorants used in the goggles for gas welding are mainly iron oxide, cobalt oxide, etc., which are yellow-green and can absorb light waves with wavelengths below 500 urn. The transmittance of visible light is below 1% and only a small amount of infrared rays by. This kind of glasses is specially used for welding in gas welding operation.
The ultraviolet rays generated by the electric welding of goggles for electric welding will cause damage to the cornea and conjunctiva tissues (28nm light is the most serious) when the eyeball is irradiated for a short time. The strong infrared rays produced can easily cause opacity of the eye lens. Welding goggles can block the above infrared and ultraviolet rays very well. This kind of lens is based on optical glass and uses coloring agents such as iron oxide, cobalt oxide and chromium oxide. In addition, a certain amount of cerium oxide is added to increase the absorption of ultraviolet rays. The appearance is green or yellow-green. It can block all ultraviolet rays, the infrared transmittance is less than 5%, and the visible light transmittance is about 0.1%.
There are two kinds of blue goggles. One is colored iron oxide and cobalt oxide, and the filament is purple red with it, and the other is colored with copper oxide and manganese oxide, and the filament is white with it. . They can all absorb the dazzling glare in the 500-600nm (visible light sensitive area of the human eye), the light transmittance at 400nm is below 12%, and it also has a certain absorption effect on ultraviolet rays. It is suitable for various industrial high-temperature furnaces. Personnel wear.
Crimson glass glasses This kind of spectacle lens is a kind of dark red glass colored with cadmium sulfide and cadmium sulphide selenide, which can absorb all the light in the wavelength band below 600nm. It can be used as goggles for medical or industrial personnel operating X-ray fluoroscopy equipment.
Laser protective glasses There are two forms of laser protective glasses, namely reflective and absorptive. The surface of the former is coated with a metal film by vacuum coating method, and the reflectivity of the laser wavebands with wavelengths of 532nm, 694nm and 1060nm is greater than 99.5. %; The latter lens can fully absorb the 1060nm laser waveband. The lens must be equipped with a closed or semi-closed frame to prevent the laser from bypassing the lens and entering the eye. It can be used as protective glasses for laser operators.
Microwave protective glasses Microwave is an electromagnetic wave with a wavelength of about 1nm-1M. It can also cause harm to people, especially eyes. Under the action of strong microwaves, it can cause eye fatigue, dry eyes and dizziness, and can even cause lens opacity, cataracts and retinal damage. It is protected by spraying tin tetrachloride on the surface of the lens and a metal compound that can increase conductivity, forming a multilayer conductive film on the surface of the lens, which plays a role in shielding microwaves. Because the microwave can bypass the lens and enter the eye, the frame of the lens should also be shielded to prevent the damage to the eye caused by the microwave.