Several characteristics of laser protective glasses
There are so many harmful lasers and harmful rays in life that damage our eyes and well-being from time to time. It is believed that for us more and more problems in life, our lives and well-being are deeply affected. It is very necessary to face the application of diversified laser protective glasses, but there are many types of such equipment. First of all, we must understand protective glasses before choosing laser protective glasses. Laser protective glasses can be divided into three types: red absorption type, reflective type and composite type.
Absorptive goggles are designed to absorb a large part of the light energy of a certain wavelength or a certain wavelength to complete the protection. They are made of a large amount of dye in glass or polycarbonate plastic. The dye can absorb one or several specific wavelengths of laser light and allow other wavelengths of light to pass through, thus achieving effective protection.
According to the way of reflection, reflective laser protective glasses can be divided into intervention type and diffraction type.
(1) Interventional type Interventional goggles are vapor-deposited multilayer dielectric films on a glass substrate to selectively reflect laser light of a specific wavelength or specific wavelengths to complete protection.
In practice, the incident laser beam is not necessarily perpendicular to the incident surface. When the incident beam deviates from the normal direction of the filter, the optical path difference Δ confirmed by (2) becomes smaller; the wavelength of the laser beam enhanced by reflection interference obtained by (4) becomes shorter, so the so-called 'blue direction' Frequency shift '. Obviously, when the blue frequency shift is serious, the protective glasses will lose their protective effect. In addition, two or more media are alternately evaporated on the surface of the glass substrate. Different media layers are respectively enhanced by the reflection of different wavelength lasers. The cumulative effect of dozens or even hundreds of media can make the optical density of laser protective glasses It becomes very large, and the protective wavelength also becomes more.
(2) Diffraction type Diffraction type protective lens is a holographic optical element made of dichromate gelatin or photosensitive polymer film layer, which uses the principle of backward diffraction to complete the reflection of the laser and stop the protection.
When established, it appears that specular reflection occurred on the lens. In theory, the reflectivity can reach any value less than 100% . The hologram wavelength is twice the hologram interference fringe spacing. Therefore, by controlling the spacing of the hologram intervening fringes, the laser light of a specific wavelength can be reflected as required, and light of other wavelengths can be allowed to pass through.
Composite laser protective glasses are made by adding one or more dyes to the substrate, and then vapor-depositing multiple dielectric reflection film layers on it. Because this kind of goggles separates the advantages of absorptive goggles and reflective goggles, the laser protection performance is improved to a certain level.