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Introduction to the types of optical glass and coating methods

Update:16-04-2021
Summary:

As an older material, glassQuartz Glass for Optics can […]

As an older material, glassQuartz Glass for Optics can be used not only in the fields of architecture and art, but also in medical treatment and instrumentation. Different types of glass have different characteristics and must be paid attention to when using them. However, most people don't know enough about glass, which often causes some misunderstandings and troubles. In this article, we will analyze the different types of optical glass and introduce several coating methods on the glass surface.
Optical glass

1. What are the different types of optical glass

1. Colorless optical glass

There are specific requirements for optical constants, and it has the characteristics of high transmission in the visible region and no selective absorption and coloring. According to the size of Abbe number, it is divided into crown type and flint type glass, and each type is divided into several types according to the refractive index, and they are arranged in order according to the refractive index. Mostly used as lenses, prisms, mirrors, etc. of telescopes, microscopes, cameras, etc.

2. Anti-radiation optical glass

It has a large absorption capacity for high-energy radiation. There are high-lead glass and CaO-B2O2 system glass. The former can prevent γ-ray and X-ray radiation, and the latter can absorb slow neutrons and thermal neutrons. It is mainly used in the nuclear industry. , Medical field, etc. as shielding and peeping window materials.

3. Irradiation resistant optical glass

Under certain γ-ray and X-ray irradiation, the transmittance in the visible area changes less, and the variety and brand are the same as colorless optical glass, which is used to manufacture optical instruments and peeping windows under high-energy irradiation.

4. Colored optical glass

Also known as filter glass. It has selective absorption and transmission properties for specific wavelengths in the ultraviolet, visible and infrared regions. According to the spectral characteristics, it is divided into three types: selective absorption, cut-off and neutral gray; according to the coloring mechanism, it is divided into ion coloring, metal colloid coloring and sulfur selenium There are three types of chemical coloring, which are mainly used to manufacture optical filters.

5. Ultraviolet and infrared optical glass

It has a specific optical constant and high transmittance in the ultraviolet or infrared band, and is used as an ultraviolet or infrared optical instrument or as a window material.

6. Optical Quartz Glass

With silica as the main component, it has the characteristics of high temperature resistance, low expansion coefficient, high mechanical strength, and good chemical properties. It is used to manufacture prisms, lenses, windows and mirrors that have special requirements for transmission in various wavelengths. In addition, there are also photomasks, liquid crystal display panels, and thin-plate glass used in the manufacture of large-scale integrated circuits; magneto-optical glass in which the polarization plane rotates when light passes through the glass along the direction of magnetic force; light passes through in a certain direction Acousto-optic glass with light diffraction, reflection, convergence or light frequency shift occurs when ultrasonic glass is used.

Two, there are several coating methods on the glass surface

Coating is to coat a very thin transparent film on the surface to reduce light emission. There are many production methods for coated glass, mainly including vacuum magnetron sputtering method, vacuum evaporation method, chemical vapor deposition method and sol-gel method.

1. Magnetron sputtering coated glass can design and manufacture multi-layer complex film system by using magnetron sputtering technology, which can plate a variety of colors on the white glass substrate. The film has good corrosion resistance and wear resistance, which is suitable for production. And one of the more used products.

2. Compared with magnetron sputtering coated glass, there is a certain gap between the variety and quality of vacuum evaporation coated glass, which has been gradually replaced by vacuum sputtering.

3. The chemical vapor deposition method is to introduce reaction gas into the float glass production line to decompose on the hot glass surface, and evenly deposit on the glass surface to form coated glass. The method is characterized by low equipment investment, easy control, low product cost, good chemical stability, and thermal processing. It is one of the more promising production methods.

4. The sol-gel method for producing coated glass has a simple process and good stability. The disadvantage is that the product's light transmittance is too high and the decoration is poor.

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