Factors affecting the price of bandpass filters

Definition of bandpass filter: In a certain frequency band, there is only a small band with high transmittance in the middle, and the cutoff band with high reflectivity is on both sides of the band. This type of filter is called a bandpass filter. The main function is spectral selection, which allows the desired light to pass through and cuts off unwanted light. At present, bandpass filters have a wide range of applications as optical components for selecting spectra and filtering out unwanted light.

There are several factors that affect the price of bandpass filters, including:

1、 Substrate material, as we all know, is an important factor affecting the price of optical filters. In optical filters, quartz substrate coated filters have higher costs than ordinary optical glass filters. Of course, in optical glass, imported optical glass such as Schott, Corning and other glass are superior to ordinary domestic optical glass.

2、 The center wavelength is also the peak wavelength. Generally speaking, the higher the transmittance, the higher the transmittance. However, biological instrument filters used in the ultraviolet band do not necessarily require high transmittance.

3、 The cut-off depth of narrowband filters can shield the influence of clutter on inductive components, enabling optical sensing elements to respond to more accurate signals.

4、 Width of the passband. The passband width is generally not good or narrow, but in bandpass filters, the higher the transmittance, the narrower the passband width, and the lower the cutoff depth OD value. However, the production process of this bandpass filter has a high production cost.

Other optical characteristics of bandpass filters:

The higher the cutoff rate OD, the narrower the direct bandwidth, and due to the higher reflectivity of the cutoff film layer, the higher the absorption and scattering, resulting in a lower peak transmission rate of the bandpass filter. In all dielectric bandpass filters, if the transmittance of the thin films on both sides is not equal, it will also affect the decrease of the bandpass rate of the filter.

This filter is used as a precision optical component, and the film layer on the surface of the filter is easily scratched. In addition, our improper cleaning and storage habits can also cause damage to the optical film on the surface of the lens, thereby reducing the optical performance and service life of the filter. Therefore, we can see that the maintenance and storage of filters are an important part of our use.