Optical lens is in optical glass made lenses, generally refers to through regulation of visible light lenses, optical lenses must be passing through an optical measuring instruments, the purity test, transparency, uniformity, refractive index and dispersion rate is in compliance with specifications, qualified glass block after forging heating, optical lens blanks. After the optical lens is fine grinding, the surface still has a thick layer of cracks. The method to eliminate the crack layer is polishing.

1, colorless optical glass. The optical constants have specific requirements, with the visible area of high transmittance, no choice of absorption and color characteristics. Abbe number size according to the crown and flint glass, all kings and according to the refraction rate level is divided into several kinds and according to the refraction rate size are arranged in order. Used as a telescope, microscope, camera, lens, prism, mirror, etc..

2, anti radiation optical glass. Larger absorption capacity, high lead glass and CaO-B2O2 system glass on high energy irradiation, the former can prevent the gamma ray and X-ray radiation, which can be slow neutron and thermal neutron absorption, mainly used as the shielding and peeped through the window materials in nuclear industry, medical field, and so on.

3, colored optical glass. Filter glass. Ultraviolet, visible and infrared region specific wavelength selective absorption and permeation, according to the spectral characteristics of points for selective absorption, cut-off and neutral grey 3 class; according to the coloring mechanism are divided into 3 types of coloring ion, metal colloid coloring and selenium and sulfur compounds coloring, mainly for manufacturing filter.

4, optical quartz glass. Using silica as the main ingredient, with characteristics of high temperature resistance, thermal expansion coefficient is low, high mechanical strength, chemical properties good for manufacturing of various bands through the special requirements of the prism, lens, window, mirror, etc..

5, ultraviolet and infrared optical glass. In the ultraviolet or infrared wave band with a specific optical constant and high transmittance, used as ultraviolet, infrared optical instrument or as a window material.

6, radiation resistant optical glass. Under a certain gamma ray and X ray irradiation, the visible area transmission rate is less, and the variety and grade are the same as the colorless optical glass, which is used for the manufacture of optical instruments and peep window under high energy irradiation.

Neutral gray mirror, also known as the gray density mirror, referred to as ND mirror, is a piece of gray, pure and transparent advanced optical glass. Its role is by weakening through the lens to reduce light exposure. This filter action is a non selective. That is to say, ND filter of different wavelengths of light for their ability to reduce is equal, uniform, weaken the light only played the role of, and color of the original object does not produced any effect, so it can be true representation of scene contrast and color photography and black and white photography apply equally. According to the "block" of light intensity, neutral gray mirror has multiple densities are available, such as ND2, ND4, nd8 (respectively on the extension of a file, file 2 and 3 file shutter speed) can also be more neutral gray mirror used in combination. It is not difficult to see that the figure behind the ND, that represents the ability to block the ND mirror light. The larger the value of ND, the more serious partial color, the general quality of products are using other techniques for wavelength, as far as possible to minimize the distortion of color and the most faithful to restore.

ND mirror only reduces the intensity of light, so it does not affect the final image of the color, it will not affect the camera's white balance and automatic exposure. Use the ND mirror, will not be subject to the color and contrast of the object to produce any effect. In addition, since the SLR is carried out by the lens of the camera, so the ND lens will not have any impact on the camera's automatic exposure system.

In short, the need for people to use a slow shutter, or reduce the case of external light, ND mirror is very useful additional lenses. Of course, due to different lens aperture is different, so the ND mirror also has different caliber, in the use of the lens according to the caliber of the choice of different diameter ND mirror.

There are many kinds of glass, optical glass is one of them, it is able to change the direction of light propagation. It is widely used in optical instruments, such as lenses, prism, etc.. Optical glass, it must meet the requirements of the light, it is not more than the general glass, the quality of the optical glass is also very high. Qualified optical glass it needs to meet the following requirements.

First of all, optical constants of optical glass and optical constants of the same batch of glass should be the same, the first type optical glass of different wavelengths of light have the provisions of the standard index of refraction, as a basis for optical designers in the design of optical system.

So the optical constants of factories for the production of optical glass must be in the numerical values of certain allowable deviation range within, otherwise it will make the actual as design quality and expected results inconsistent and affect the quality of optical instruments. At the same time, because the same batch of instruments are often used in the same batch of optical glass manufacturing, in order to facilitate the uniform calibration of the instrument, the deviation of the refractive index of the same batch of glass is more strict than their standard deviation.

Secondly, it needs to have a high degree of transparency, the brightness of the optical system into the image and the transparency of the glass into a proportional relationship. Optical glass to a certain wavelength of light transparency in the light absorption coefficient K. Light passes through a series of lenses and lenses, whose energy is partially absorbed by the interface of the optical part and the other part is absorbed by the medium (glass). The former with glass refraction rate increases, the high refractive rate of glass this value is very large, such as the heavy flint glass surface optical reflection loss of about 6%.

The electrical conductivity of the transparent quartz glass is 10-17-10-16 West / m, the conductivity of the opaque quartz glass is 10-14-3.2 * 10-13 / m, and its value is related to the purity of the quartz glass. Xiamen Yi only special quartz glass dielectric constant at room temperature and 0-106 Hz frequency, the dielectric constant of the transparent quartz glass is 3.70; opaque quartz glass 3.50, elevated temperature, a slight increase in the dielectric constant, after 450oC, dielectric constant increased significantly.

Dielectric loss

The relationship between dielectric loss and temperature of quartz glass is increased with the increase of temperature, the dielectric loss increases more than 350oC, and the dielectric loss increases with the increase of temperature.

Chemical properties of acid and alkali resistant quartz glass belongs to acidic materials, except hydrofluoric acid and hot phosphoric acid, to any other acid showed as inert, is the best acid material. At room temperature, alkali and salt on the quartz glass corrosion degree is minimal, so do not rule out using quartz glass in these agents.

About the relationship between thermal conductivity and thermal conductivity of quartz glass, quartz glass is a kind of high purity special industrial technology glass containing only silicon dioxide (SiO2). As with other materials can not be replaced by a series of special properties, as well as very low thermal conductivity rate, and excellent thermal shock resistance, high deformation temperature and softening temperature, low heat conduction ability, and very low dielectric loss from the ultraviolet to the infrared extremely wide spectral range optical permeability. To make it play a very important role in modern industry and high technology field.

The band-pass filter is also called interference filter. Is to eliminate unwanted stray light, only need to light through, such as rice and beans mixed together. You'd better put them all down to only through a rice sieve, filter, to distinguish between the. This band pass filter is to play this role.

From spectral curves said, can let the light from a wavelength or wavelength through, similar to the great wall shape (from the shape of pulse) or approximation to Z are called bandpass and "Z" often called long wave or short wave.

The width of the band is divided into two types: narrow band and wide band. Narrow band filters, for example, half of the bandwidth 20nm spectrum through the narrow band, if you want to 40nm, 100nm bandwidth is also called narrow band, not against the.

From the spectra of the length (regional): ultraviolet, visible, near infrared, infrared and far infrared band pass filter (commonly called UV 180~400nm visible light 400 ~ 700nm, near infrared 700~3000nm, infrared 3000nm~10um.

NOUN interpretation:

1) the center wavelength (CWL): the use of the wavelength of the peak value is 850nm, such as light source LED light, the center wavelength is 850nm demand.

2) transmittance (T): hypothesis was 100%, passes through the filter some loss for the initial value, through the assessment that only 85% of the, it can put the filter transmittance only 85%, simply said that the number of losses, everybody wants to do all things loss of the smaller the better.

(3) peak transmittance (Tp) >85%.

4) semi bandwidth (FWHM): simple is the highest transmission rate of 1 / 2 place corresponding wavelength, with a wavelength of about value subtraction, for example, the peak is the best 90%, 1 / 2 is 45%, 45% of the corresponding wavelength around is 800 nm and 850 nm and the bandwidth is 50nm.

(5) the cut-off rate (Blocked): the corresponding transmission rate. Due to the rate of 0%, it is very difficult to know that the sun can make the underground tree into carbon, only rely on this thin film to cover up everything is very difficult, can only choose it through the smaller the better. The smaller the spectral transmittance is, the better.

6) cutoff band: minimum area of acceptable wavelength.

(7) (coating hard): oxide material plating (e.g., Ta2O5, SiO2, etc.).

8) piamater: removing oxide materials, such as fluoride (MgF2), sulfide, commonly used, such as aluminum, gold and silver.

9) increase through the film (AR): less reflective coating, increase the wear of light, so that the most effective use of light energy.

10) BBAR: back broadband penetration film.

Quartz glass Mohs hardness up to seven, with high temperature and expansion coefficient low, thermal shock resistance, chemical stability and electrical insulation performance is good and through ultraviolet and infrared. In addition to hydrofluoric acid and hot phosphoric acid, has good acid resistance to acid. Divided into transparent and opaque by two categories of transparency. The purity is divided into three types, high purity, general and doped. Quartz glass using high purity silica sand as raw materials, produced by traditional method is melt quenching method (material to be heated to the melting temperature, followed by rapid cooling to the glass solid phase); production of ultra high purity and UV transmittance of transparent glass to silicon gasification, oxidation silicon dioxide and heating dissolution process.

Today, we come to understand the difference between quartz glass and ordinary glass:

1, color: quartz glass is a single component of silica glass, so it must be colorless, ordinary glass generally have some color.

2, flame calcination: hydrogen oxygen flame and so on can be more than one thousand degrees of temperature calcination, look to soften the light, burning colorless is the quartz glass.

Quartz glass has a very low thermal expansion coefficient, high resistance to temperature, excellent chemical stability, excellent electrical insulation, low and stable ultrasonic delay performance, best through the UV spectral properties and through visible light and near infrared spectral properties, and has a higher than ordinary glass mechanical properties. Therefore, it is a sophisticated technology of modern space technology, atomic energy industry and national defense equipment, automation system, as well as one of the excellent material for semiconductor, metallurgy, chemical, electric light source, communication, light industry, building materials and other industry indispensable.

The difference between optical glass and other glass is that it is a part of the optical system and must satisfy the requirements of optical imaging. Therefore, the determination of the quality of optical glass also includes some special and more stringent indicators.

Today, we talk about the importance of optical glass must have a high degree of transparency.

The relationship between the brightness of the optical system and the transparency of the glass. Optical glass to a certain wavelength of light transparency in the light absorption coefficient K. Light passes through a series of lenses and lenses, whose energy is partially absorbed by the interface of the optical part and the other part is absorbed by the medium (glass). The former with glass refraction rate increases, the high refractive rate of glass this value is very large, such as the heavy flint glass surface optical reflection loss of about 6%. Therefore, the main way to improve the transmission efficiency is to reduce the reflection loss on the surface of the lens, such as the coating surface coating, and so on. For large size optical components such as the telescope's objective, due to its great thickness, the optical system's transmission rate is mainly determined by the optical absorption coefficient of the glass itself. By improving glass raw material purity and in the whole process from the ingredients to the melting prevent any coloring impurities mixed, generally can make optical glass optical absorption coefficient less than 0.01 (i.e., thickness is 1 cm glass to light through rate is more than 99%).