Some optical industry workers may be wondering what is the difference between narrowband filters and bandpass filters? Let's discuss it today.
Band pass filter optics allow optical signals to pass through in a specific wavelength band, while optical signals on both sides that deviate from this band are blocked. The passband of bandpass filters is relatively wide, generally half a The bandwidth is above 40nm!
The narrowband optical filter is divided into the bandpass filter, which belongs to a kind of bandpass filter. Its definition is the same as that of the bandpass filter, which allows the optical signal to pass through in a specific wavelength band. .
The optical signals on both sides that deviate from this band are blocked, but the narrow-band filter is relatively narrow.
The narrow-band filter mainly adopts the technology of all-dielectric hard coating and the principle of medium interference. On the basis of highlighting the characteristics of the narrow-band filter, the optical performance has nothing to do with the thickness of the substrate. The narrow-band filter is more convenient for built-in instrument imaging systems.
In order to improve its optical performance and apply it effectively, special optical material substrates are used to solve the problems of mildew and unstable optical performance of traditional absorption synthetic glass. The products are produced according to the customer's requirements.
The single-piece narrow-band filter does not use gluing or hard coating, and has long service life, small temperature drift, strict control of production process, and small error in product size and optical index.
Ultra-thin optical glass, high transmittance, good finish, small thickness tolerance, good flatness and other optical characteristics strong characteristics.
Its definition is the same as that of band-pass filtering, that is, this filter allows optical signals to pass in a specific wavelength band, and the optical signals on both sides that deviate from this band are blocked. The passband of narrow-band filters is relatively narrow. Generally, it is less than 5% of the central wavelength value.
Both of the above make the image band chromatic and seriously affect the imaging quality, even in the paraxial region. We define the wavelength of this diffraction direction, that is, the wavelength of the reflected light from the groove surface with the right diffraction direction on the grating as blaze wavelength.
This feature can be used to align the center wavelength within a certain range. The advent and application of electronic computers have greatly promoted the work of optical design.
The monitoring distance is long, up to 1500-5000 meters. The object distance ratio infrared thermometer to determine the target can be divided into monochromatic thermometer and dual color thermometer (radiation colorimetric thermometer) according to the principle.