Definition and classification of infrared cut-off filters

The infrared cut-off filters can effectively block the infrared light that interferes with the imaging quality and maintain high transmittance of visible light, making the resulting image more in line with the best feeling of the human eye.

The infrared cut-off filter, also known as infrared filter or endothermic filter (R, referred to as RCF), is a filter used to filter infrared wavebands. The infrared cut-off filter uses precision optical coating technology to alternately coat optical substrates such as white glass, blue glass or resin sheets with high and low refractive index optical films. Due to the refraction of visible and infrared light into different target surfaces after entering the lens, infrared light will form a virtual image on the target surface of visible light imaging, affecting the color and quality of the image. The infrared cutoff filter can eliminate the impact of infrared light on imaging by achieving near-infrared region cutoff, and is an essential component of high-performance cameras.


The downstream end products of infrared cut-off filters currently do not have high requirements for image imaging quality and do not need to consider spatial filtering. Instead, they focus on light wave filtering (i.e. infrared light suppression). Infrared light suppression is one of the essential functions of image sensors. This is because CCD/CMOS has a different sensitivity to light compared to the human eye, where the human eye can only see visible light of 380-780mm, while CCD/CMOS can sense infrared and ultraviolet light, especially sensitive to infrared light. Therefore, It is necessary to use an infrared cut-off filter to suppress infrared light and maintain high transmittance of visible light α The sensitivity of CD/CMoS to light is similar to that of the human eye, so that the captured image also conforms to the sensitivity of the eye.

It can be seen that by adding an infrared cut-off filter to the CCD/CMOS imaging system, the infrared light that interferes with the imaging quality can be effectively blocked, making the resulting image more in line with the best feeling of the human eye. The application fields of infrared cut-off filters include lens systems such as mobile phone cameras, computer cameras, car mounted cameras, etc. They can also be applied to fields such as digital cameras, digital cameras, and monitoring systems, with the vast majority involved α The field of CD/CMOS imaging systems ultimately achieves the use of RCF to eliminate the impact of infrared light on CD/CMS imaging. In addition, terminal products can also improve imaging quality by filtering out infrared light, making their imaging more in line with the human visual experience.

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Infrared cutoff filters are irreplaceable for downstream end products. In the future, the product structure of infrared cutoff filters will be further segmented with the improvement of downstream product performance. The requirements of the generation of CCD/CMOS systems for infrared cutoff filters are higher surface quality, more standardized specifications, and lower manufacturing costs.

In the downstream of the infrared cut-off filter industry, consumer electronics are the main application fields (such as digital cameras, digital cameras, video surveillance cameras, etc.). With the continued rapid development of smart phones, car camera, security monitoring, smart home and other industries, the market demand for high-definition camera heads is strong, which greatly drives the market demand of IRCF


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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