What Is an Infrared Filter?

Infrared filters are mainly used in the field of security monitoring, infrared gas analyzers, night vision products, infrared detectors, infrared receivers, infrared sensors, infrared communication products. Specific products such as: surveillance cameras, remote controls, infrared curtain wall products, infrared sensor toilets, faucets, hand sanitizer devices, infrared thermometers, infrared printers, interactive whiteboards, infrared touch screens, fingerprint recognition machines, face recognition systems Wait.

Infrared filter

Means

The infrared band includes a wide range of wavelengths, from 780nm to 14um, which are divided into near infrared, mid infrared and far infrared. Near infrared (code IR-A, wavelength 780 1500nm, NIR), middle infrared (IR-B, 1500 6000nm, MIR), far infrared (IR-C, 6000 14000nm, FIR)

In terms of materials , there are optical glass coatings, colored glass, and plastic infrared filters. This refers to a near-infrared filter. If it involves the mid-far infrared, the materials include Si, ZnSe, Sapphire, CaF2, quartz glass and so on.

In terms of optical characteristics , there are IR long pass filters and IR bandpass filters.

Among them, long pass type,

(1) Made of colored glass, usually black, such as IPG-800. It absorbs visible light and allows infrared light to pass through. If you look at the sun through this infrared filter, you can still see a red sun. Suitable for infrared imaging.

(2) An infrared filter is made on the optical white glass by vacuum coating, such as IPGC-720. This type is also called an optical cold mirror, which reflects visible light and allows infrared light to pass through. The exterior looks silver, like a mirror. If it is a mid-far infrared filter, it should be coated on Si, Sapphire, and quartz glass.

Infrared filter

(3) An infrared plastic filter made of special plastic has a black appearance. If you look at the sun through this infrared filter, you can also see a red sun. The material of this plastic can be PC or PMMA.

Besides band-pass type, band-pass filters are made by vacuum coating. For near-infrared bandpass, coating is on white glass. If it is mid-far infrared, it will be coated on Sapphire. Everyone can add. Among them, the corresponding light sources of the near-infrared band-pass filter are mainly infrared IR LED and infrared laser, so the main wavelengths are 808nm, 850nm, 905nm, 940nm, 1064nm, and there are also uncommon 780nm. Therefore, the wavelengths of the commonly used near-infrared filters are mainly these. The corresponding models are BPF-850, NBF-808, BPF-940.