The functional membrane material includes:
Window film, photovoltaic film, photoelectric film, garment film, separating film, protective film, separating film, water treatment film, flame retardant film, water vapor high barrier film, negative ion release film, inorganic nano-added functional film, battery membrane, etc.
In the field of industry, it includes:
Display film field, photoelectric film field, new energy film field, industrial automobile film field, semiconductor packaging film field, building film field, life science field, etc.
The upstream raw materials concerned include:
General plastics (PE/PP/PVC/PS), engineering plastics (PET/PA/PC/POM), plastic elastomers (PU/TPU/TPE), etc.
What is an optical film?
Optical thin films are coated with one or more dielectric or metal films or combinations of these two kinds of films on optical components or independent substrates to change the transmission characteristics of light waves, including transmission, reflection, absorption, scattering, polarization and phase change. Therefore, the surface transmittance and reflectivity of components in different bands can be adjusted by appropriate design, and the light of different polarization planes can also have different characteristics.
Production Mode of Optical Thin Films
Generally speaking, the production methods of optical thin films are mainly divided into dry process and wet process.
The so-called dry type is that no liquid appears in the whole processing process.
The general method of wet coating is to mix the components with various functions into liquid coatings, coat the base materials with different processing methods, and then dry and solidify the liquid coatings into products.
Classification of Optical Thin Films
Optical thin films can be classified according to their uses, characteristics and applications.
Reflector film, antireflective film/ antireflective film, filter, polarizer/ polarizer film, compensation film/phase difference plate, alignment film, diffusion film, brightening film/prism film/concentrator, shading film/black and white glue, etc. The related derivatives include optical protective film, window film and so on.
Reflective coatings can be generally divided into two categories, one is metal reflective coatings, the other is all dielectric reflective coatings.
The advantages of metal reflective coatings are simple preparation process and wide wavelength range, while the disadvantages are large light loss and lower reflectivity. In order to further improve the reflectivity of the metal reflective film, several layers of dielectric layer with certain thickness can be added to the outside of the film to form a metal dielectric reflective film. It should be pointed out that the metal dielectric film increases the reflectivity of a certain wavelength (or a certain wave region), but destroys the characteristics of the neutral reflection of the metal film.
All-dielectric reflective film is based on multi-beam interference. Contrary to the antireflective film, the reflectivity of the optical surface can be increased by coating a film with a refractive index higher than that of the matrix material on the optical surface. The simplest multilayer reflection is made by alternating evaporation of two materials with high and low refractive index. The optical thickness of each layer is one quarter of a certain wavelength. Under this condition, the reflected light vectors on the superimposed surfaces have the same vibration direction. The synthetic amplitude increases with the increase of film layers.
Antireflective film main function is to reduce or eliminate the reflective light of the lens, prism, plane mirror and other scientific surfaces, thereby increasing the transmittance of these elements and reducing or eliminating the stray light of the system.
Antireflective film are based on the fluctuation and interference of light. If two light waves with the same amplitude and wavelength are superposed, the amplitude of light waves will increase; if two light waves have the same origin and the wave path is different, if the two light waves are superposed, the two light waves will cancel each other out. Anti-reflective coating is based on this principle. It coats the surface of the lens with anti-reflective coating, which makes the reflected light from the front and back surfaces of the film interfere with each other, thus counteracting the reflected light and achieving the effect of anti-reflection.
The filter is made of plastic or glass and special dyes. The red filter can only let the red light pass through, and so on. The refractive index of glass sheet is almost the same as that of air. All color light can pass through, so it is transparent. But after dyeing, the molecular structure and refractive index of glass sheet change, and the passage of some color light changes. For example, when a white light passes through a blue filter, it emits a blue light, while green light and red light are very few, and most of them are absorbed by the filter.
The full name of Polarizing Film should be polarizer. The imaging of LCD must depend on polarized light. The main function of polarizer is to change the natural light without polarization into polarization, and twisting characteristics of liquid crystal molecule, so as to control the passage of light, improve the transmittance and viewing angle range, and form anti-glare functions.
Compensation Film/Phase Difference Plate
The compensating principle of the compensating film is to correct the phase difference of liquid crystal in various display modes (TN/STN/TFT (VA/IPS/OCB). In short, it is to compensate the birefringence of liquid crystal molecules by symmetry. If we want to distinguish it from its function purpose, we can divide it into phase difference film, color difference compensation film and angle of view enlargement film. Compensation film can reduce the light leakage of LCD in dark state, and can greatly improve image contrast, chromaticity and overcome some gray scale inversion problems in a certain perspective.
The alignment film is a thin film with straight strip scratches. Its function is to guide the alignment direction of liquid crystal molecules. A parallel groove is printed on the ITO film by PI coating solution and roller on the glass substrate which has been steamed with transparent conductive film (ITO). Then the liquid crystal can lie in the groove horizontally according to the direction of the groove to achieve the purpose of aligning the liquid crystal in the same direction. This film has one direction, that is, the Alignment film.
Diffusion film is a key component of TFT-LCD backlight module. It can provide a uniform surface light source for LCD. Generally, the traditional diffusion film is mainly composed of chemical particles which are added to the substrate of diffusion film as scattering particles. However, the existing diffusion plate has particles scattered among the resin layers, so the light passes through the diffusion layer continuously in two media with different refractive index. As a result, many phenomena of refraction, reflection and scattering of light will occur, thus resulting in the effect of optical diffusion.
Brightening film/ prism sheet/concentrator
The brightening film is also called Prism Sheet, often referred to as BEF, which is the key component of TFT-LCD backlight module. It mainly uses the principle of refraction and reflection of light to correct the direction of light by using prism, so that the front of light can be concentrated, and the unused light outside the viewing angle can be recycled and utilized. At the same time, the overall brightness and uniformity can be improved to achieve the effect of brightening, also known as the concentrator.
Shading film/black-and-white glue
Black-and-white shading film is mainly used in backlight, which plays a role of fixing and shading (shading edge light and lamp position light), also known as shading film, black-and-white film, referred to as black-and-white rubber (can be said to be a double-sided tape).
For this kind of products, SFEP can provide Japanese Tosoh antiblocking agent, mainly composed of nanoparticles and micron condensate. The refractive index is similar to any plastic film. It can effectively prevent the influence of optical properties, has a fairly narrow particle size distribution, and provides excellent transparency to the film.