Bandpass Filter
A bandpass filter is also known as an interference filter. It is to eliminate the required stray light, just pass through the required light, such as mixing rice and soybeans together. It is best to pour them all onto the rice screen, sieve them out, and then distinguish them. The function of a bandpass filter is this.
According to the spectral curve, light can pass through one or more wavelengths, similar to the Great Wall shape (distance pulse) or Z-shape, which is called bandpass; z” Type is usually referred to as long wave or short wave.
There are two types of bandwidth: narrowband and broadband. Narrowband filters, for example, a spectral channel with a half bandwidth of 20nm is called narrowband. If you want to pass through a 40nm or 100nm bandwidth, this is generally called broadband.
The spectrum adopts bandpass filters for ultraviolet, visible, near-infrared, infrared, and far-infrared (commonly known as ultraviolet 180-400nm, visible 400-700nm, near-infrared 700-3000nm, infrared 3000-10um or above).
Noun Explanation:
1、 Center wavelength (CWL): Using wavelength, if the main peak of the light source is 850nm, the required center wavelength is 850nm.
2、 Transmittance (t): Assuming the initial value of light is 100%, there will be loss after passing through the filter, and only 85% is obtained through evaluation. Therefore, the transmittance of the filter is only 85%. In short, everyone hopes that the smaller the loss, the better.
3、 Peak transmittance (Tp)>85%.
4、 Half width at half maximum (FWHM): It is the wavelength corresponding to the highest transmittance of 1≤ 2, minus the value of the left and right wavelengths. For example, the peak is 90%, 1≤ 2 is 45%, 45% corresponds to 800nm and 850nm, and half of the bandwidth is 50nm.
5、 Cut off rate: The transmittance corresponding to the cut-off zone. Because it is difficult to achieve a 0% transmittance, it is difficult to cover everything with this type of film. The lower the transmittance, the better, which means that the unwanted spectral transmittance is better.
6、 Cut off band: the minimum acceptable wavelength range that you do not want.
7、 Hard coat: Electroplating of oxide materials (such as Ta2O5, SiO2, etc.).
8、 Soft film: In addition to oxide materials, such as sulfides, fluorides (MgF2), commonly used gold, silver, aluminum, etc.
9、 Anti reflective film: Anti reflective film can increase the penetration of light and make the most effective use of light energy.
10、 BBar: Broadband anti reflective film.
According to the spectral curve, light can pass through one or more wavelengths, similar to the Great Wall shape (distance pulse) or Z-shape, which is called bandpass; z” Type is usually referred to as long wave or short wave.
There are two types of bandwidth: narrowband and broadband. Narrowband filters, for example, a spectral channel with a half bandwidth of 20nm is called narrowband. If you want to pass through a 40nm or 100nm bandwidth, this is generally called broadband.
The spectrum adopts bandpass filters for ultraviolet, visible, near-infrared, infrared, and far-infrared (commonly known as ultraviolet 180-400nm, visible 400-700nm, near-infrared 700-3000nm, infrared 3000-10um or above).
Noun Explanation:
1、 Center wavelength (CWL): Using wavelength, if the main peak of the light source is 850nm, the required center wavelength is 850nm.
2、 Transmittance (t): Assuming the initial value of light is 100%, there will be loss after passing through the filter, and only 85% is obtained through evaluation. Therefore, the transmittance of the filter is only 85%. In short, everyone hopes that the smaller the loss, the better.
3、 Peak transmittance (Tp)>85%.
4、 Half width at half maximum (FWHM): It is the wavelength corresponding to the highest transmittance of 1≤ 2, minus the value of the left and right wavelengths. For example, the peak is 90%, 1≤ 2 is 45%, 45% corresponds to 800nm and 850nm, and half of the bandwidth is 50nm.
5、 Cut off rate: The transmittance corresponding to the cut-off zone. Because it is difficult to achieve a 0% transmittance, it is difficult to cover everything with this type of film. The lower the transmittance, the better, which means that the unwanted spectral transmittance is better.
6、 Cut off band: the minimum acceptable wavelength range that you do not want.
7、 Hard coat: Electroplating of oxide materials (such as Ta2O5, SiO2, etc.).
8、 Soft film: In addition to oxide materials, such as sulfides, fluorides (MgF2), commonly used gold, silver, aluminum, etc.
9、 Anti reflective film: Anti reflective film can increase the penetration of light and make the most effective use of light energy.
10、 BBar: Broadband anti reflective film.