The classification and function of infrared filters

First of all, what is an infrared filters?

Simply put, an infrared filters is an optical filter that can block ultraviolet and visible light and only transmit infrared light.

In the field of optics, infrared filters are generally colored glass filters made of optical glass coating, optical plastics (such as PC and PMAA) or optical glass with special dyes added. The filters of the above process can only allow red light to pass through, and are generally infrared filters.

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What are the specific differences among the infrared filters coated with optical glass, the infrared filters of optical plastic grade and the infrared filters of colored glass?

The biggest difference is: cost

In addition, there are also specific microscopic differences in optical parameters, as well as more options for infrared filter solutions. Borisun Optics recommends that you choose the corresponding material of infrared filter according to the application scenario you need to match and the overall cost. For more details on filter products, please feel free to contact us!

Infrared filter spectral band: UV filter 180-400nm, visible filter 400-700nm, infrared filter (near-infrared 700-3000nm, infrared 3000m-10um);

Wavelength division of infrared filters:

Infrared filters include a wide range of wavelengths, ranging from 780nm to 14um, which are further divided into near-infrared filters, mid infrared filters, and far-infrared filters. Near infrared (code | R-A, wavelength 780-1500mmNR), mid infrared (R-B, 1500-6000nmMR), and far infrared (R-C6000-14000nm, FR).

Classification of infrared filters:

In terms of materials, there are optical glass coated, colored glass and plastic infrared filters. This refers to the near-infrared filter. If it involves mid to far infrared, the material also includes Si, Z η Se, CaF2, quartz glass, etc

From the perspective of optical characteristics, there are two types: long wave pass and bandpass.

Bandpass infrared filter:

(1) Made of colored glass, usually black, such as HBW-800. It absorbs visible light and allows for the transmission of infrared light. 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 by vacuum deposition on optical white glass, such as IPGC-720, which is also called an optical cold mirror. It reflects the visible outside to let the visible light through. The appearance looks silver, like a mirror. If it is a medium to far infrared filter, it needs to be coated on Si, Sapphire, and quartz glass.

(3) Infrared plastic filters made of special plastics are generally made of PMMA and PC materials. The appearance is black, and if you look at the sun through this infrared filter, you can also see a red sun

As for band-pass type, band-pass filters are made of vacuum deposition. For near-infrared bandpass, it is coating on white glass. The corresponding light sources for near-infrared bandpass filters are mainly infrared RLED and infrared laser, so the main wavelengths are 808nm, 850nm9o5nm, 940nm, 1064nm, and there are also less commonly used 780nm. So the wavelengths of commonly used near-infrared filters are mainly these. The corresponding models include BP-850nm bandpass filter NBP-808nm narrowband filter BP-940nm bandpass filter

So what is the function of infrared filters?

Infrared filters are mainly used in the field of security monitoring, infrared gas analyzer night vision products, infrared detectors, infrared receivers, infrared sensing, and infrared communication products. Specific products include surveillance cameras, remote controls, infrared curtain wall products, infrared sensing toilets, faucets, hand sanitizer devices, infrared thermometers, infrared printers, interactive electronic whiteboards, infrared touch screens, fingerprint recognition machines, facial recognition systems, etc

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Hanzhong Brisun Optics Co., Ltd. Is the high precision optical element manufacturer provides customized production of Various optical lenses, including spherical lens, cylindrical lens, optical window, mirror, prism, filter, metal base mirror and other high-precision optical elements. The base materials include various optical glass, fused quartz, calcium fluoride (CaF2), zinc selenide (ZnSe), germanium (GE), silicon (SI), sapphire, metal and other materials. And provide antireflective film, high reflection film, spectroscopic film, metal film and other optical coatings.

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