Die optiese filmlaag is saamgestel uit 'n dun laagmedium , 'n soort optiese mediummateriaal wat die ligstraal deur die koppelvlak versprei. Die toepassing van optiese films het in die dertigerjare begin. Moderne, optiese films word wyd gebruik op die gebied van optika en opto-elektroniese tegnologie, wat verskillende optiese instrumente vervaardig.

Die belangrikste optiese dunfilmtoestelle sluit in reflektiewe film, antirefleksiefilm, polariserende film, interferensiefilter en balkverdeler, ens. Hulle word alom gebruik in die konstruksie van die nasionale ekonomie en nasionale verdediging, en kry toenemende aandag deur wetenskaplike en tegniese werkers. Die gebruik van antirefleksiefilms kan byvoorbeeld die verlies van die stroming van komplekse optiese lense tien keer verminder; die gebruik van hoë weerkaatsingsspieëls kan die uitsetkrag van die laser verdubbel; die gebruik van optiese films kan die doeltreffendheid en stabiliteit van silisium fotovoltaïese selle verbeter.

1. Struktuur

Die eenvoudigste optiese filmmodel is 'n dun laag met 'n gladde oppervlak en 'n isotrope homogene medium. In hierdie geval kan die optiese interferensie teorie gebruik word om die optiese eienskappe van optiese films te bestudeer. Wanneer 'n monochromatiese platgolf op die optiese film val, kom veelvoudige weerkaatsings en refraksies op die twee oppervlaktes voor. Die rigtings van die gereflekteerde lig en die brekende lig word gegee deur die wette van refleksie en breking, en die amplitudes van die weerkaatsde en gebreekte lig. Die grootte word bepaal deur die Fresnel-formule

2. Kenmerke

Die eienskappe van die optiese film is: die oppervlak is glad, die koppelvlak tussen die filmlae is meetkundig verdeel; die brekingsindeks van die filmlaag kan verander op die koppelvlak, maar dit is aaneenlopend binne die filmlaag; dit kan 'n deursigtige medium wees of dit kan wees

Optical film

Absorbing medium; can be uniformly normal or non-uniformly normal. The actual applied film is much more complicated than the ideal film. This is because: during preparation, the optical and physical properties of the film deviate from the bulk material, and its surface and interface are rough, resulting in diffuse scattering of the light beam; the interpenetration between the film layers forms a diffusion interface; due to the growth of the film layer , Structure, stress and other reasons, the anisotropy of the film is formed; the film layer has a complex time effect.

Filter introduction:

Used to select the optical device of the required radiation band. A common feature of filters is that no filter can make the image of a celestial body brighter, because all filters absorb certain wavelengths, which makes objects darker.

Filter principle:

The filter is made of plastic or glass and then added with special dyes. The red filter can only let red light through, and so on. The transmittance of the glass sheet is originally similar to that of air, and all colored light can pass through, so it is transparent, but after dyeing, the molecular structure changes, the refractive index also changes, and the passage of certain colored light changes. For example, a beam of white light passes through a blue filter and emits a beam of blue light, while green light and red light are very few, and most of them are absorbed by the filter.

One, anti-reflection film

Also called antireflection coating, its main function is to reduce or eliminate the reflected light from optical surfaces such as lenses, prisms, and plane mirrors, thereby increasing the light transmission of these components and reducing or eliminating stray light from the system.

Second, the optical film

The anti-reflection film is the most widely used and largest output optical film. Therefore, it is still an important research topic in optical film technology. The focus of research is to find new materials, design new film systems, and improve the deposition process. It uses the least number of layers, the simplest and most stable process to obtain the highest possible yield and achieve the most ideal results. For the laser thin film, the anti-reflection film is the weak link of laser damage, and how to increase its destruction strength is also one of the issues that people are most concerned about.

Three, reflective film

Its function is to increase the reflectivity of the optical surface. Reflective films can be generally divided into two categories, one is metal reflective film, and the other is all-dielectric reflective film. In addition, there are metal dielectric reflective films that combine the two.

Four, interference filter

Dit is 'n soort optiese film met die mees uiteenlopende en ingewikkelde struktuur. Die belangrikste funksie daarvan is om die spektrale band te verdeel. Die mees algemene steuringsfilters is afsnyfilters en banddeurlaatfilters. Die afsnyfilter kan die oorweegse spektrum in twee dele verdeel, die een deel laat nie die lig deur nie (die afsnydingsgebied genoem), en die ander deel vereis dat die lig moet deurgaan (die banddeurlaatgebied genoem). Volgens die posisie van die pasband in die spektrale streek kan dit in twee soorte langgolf- en kortgolfpas verdeel word. Hul eenvoudigste strukture is onderskeidelik, waar H en L dik lae en lae brekingsindekslae voorstel, en m die aantal periodes is. Die filmstelsel met die bogenoemde struktuur word 'n simmetriese periodieke filmstelsel genoem.

Five, spectroscopic film

According to certain requirements and certain methods, the light beam is divided into two parts. The beam splitting film mainly includes wavelength splitting film, light intensity splitting film and polarizing beam splitting film.

The wavelength splitting film is also called two-color splitting film. As the name implies, it is a film that divides the light beam into two parts according to the wavelength region. This film can be a cut-off filter or a band-pass filter. The difference is that the wavelength splitting film must consider not only transmitted light but also reflected light. Both require a certain shape of the spectral curve. The wavelength splitting film is usually used at a certain angle of incidence. In this case, the spectral curve will be distorted due to the influence of polarization. In order to overcome this effect, the problem of depolarization of the film must be considered.

The polarization beam splitting film is made by utilizing the polarization effect of the film when the light is incident obliquely. The polarization beam splitting film can be divided into two types, a prism type and a flat plate type. The prismatic polarizing film utilizes the polarization effect of the interface when Brewster angle is incident. When the light beam always enters the interface of two materials at Brewster's angle, no matter how many thin film layers there are, the reflected light of the horizontal vibration is always zero, and the light of the vertical component vibration increases with the number of thin film layers. Increased, as long as the number of layers is sufficient, the transmitted light beam can be basically vibrated in the parallel direction, and the reflected beam is basically light that is vibrated in the vertical direction, so as to achieve the purpose of polarized beam splitting. The Brewster angle at the interface of the thin film material, so the film must be plated on the prism, then the incident medium is not air but glass. The flat-type polarizing film is mainly made of the difference in the bandwidth of the reflection bands of the two polarized components of the dielectric reflective film when obliquely incident. In general high-reflection films, as the incident angle increases, the reflection bandwidth of the vertical component gradually increases, and the bandwidth of the parallel component gradually decreases. Selecting the high reflection area of ​​the vertical component and the high transmission area of ​​the parallel component as the working area can form a polarizing film that reflects the vertical component through the parallel component. The incident angle of this polarizing film is generally selected near the Brewster angle of the substrate . The working wavelength range of the prism-type polarizing film is relatively wide, and the degree of polarization can also be made relatively high, but its preparation is cumbersome, difficult to make large, and the laser resistance is relatively low. The wavelength range of flat polarizers is relatively narrow, but it can be made very large and the laser resistance is relatively high, so it is often used in strong laser systems.