Filter is an optical device used to select the required radiation band. One common feature of filters is that no filter can make the image of celestial bodies brighter, because all filters will absorb certain wavelengths, thus making objects darker. The transmittance of the glass was originally about the same as that of the air, while the filter was made of plastic or glass, and the red filter made of special dyes could only let the red light pass, and so on. So the filter plays a very important role and is widely used in landscape paintings taken by some masters in photography. Why is the theme always so prominent? This uses a filter. It can reach any wavelength from ultraviolet to infrared, and the peak transmittance of metal dielectric film filter is not as high as that of full dielectric film.
The main feature of the filter is that the size can be made quite large. Generally, the film filter can be used as an infrared filter with a longer wavelength, and the latter must be on a certain substrate. Some people have used the method of splicing to obtain the interference filter of 38cm square of the main road, which is installed on the 1.2m Schmidt telescope in the UK, and used to take monochromatic images of large area nebulae. In addition, the filter also has the function of image color restoration, such as crystal filter, which can solve the problem of false color and color drift to the maximum extent. Switch to crystal filter during the day, which can sense visible light very well, making the color bright and lifelike, and switch to transparent filter at night. The machine on the body senses more infrared rays, and most of the wavelengths of light can be turned to black at the same time through the camera. The infrared distance is farther and clearer. There are many kinds of filters, which are mainly classified according to spectral band, spectral characteristics, film material, application characteristics and other ways, such as ultraviolet filter, bandpass filter, soft film filter, light passing through the selected band is shorter than the selected wavelength. The better is the thin film filter.
Thin film filters are also widely used. They are mainly TiO2 and SiO2 thin film systems evaporated by electron beam, which have important applications. Some filters are widely used in spectral analysis biomedical machines. Vision, fluorescence microscopy, industrial automation and other industries and product fields. For example, the neutral density filter reduces the luminous flux by reducing the transmittance of the specified spectral wavelength range, which is conducive to the protection of the sensor element. It is widely used in the field of laser optics.
Hanzhong Borisun Optics Co., Ltd. specializes in the production of various filters, filter processing, filter manufacturing and research and development. The main products are: narrow band filter, band pass filter, long wave pass filter, short wave pass filter, neutral density filter, splitter, dichroic mirror, infrared cut-off filter, interference filter, reflector, laser protection lens, infrared transparent acrylic plate and various optical film lenses.
