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What is an ircut filter and what is a dual pass filter

What is an ircut filter?




Ircut filter is divided into reflection filter and absorption filter.




Reflective filters have high transmittance and relatively low reflection in the visible light domain, while in the near-infrared light domain, it is just the opposite, low transmittance and high reflection. Therefore, when the camera is shooting at an angle, the infrared light will produce a large offset and reflection. When the light is reflected many times by the lens group, a halo will be formed on the photo, which makes the photo (image) appear reddish.




The absorption filter adopts blue glass, which itself is an optical absorption material. The copper ion in the glass can absorb the infrared ray without large reflection. When the camera takes an angle, the light passes through the blue glass and will not form a halo on the photo after being reflected by the lens group for many times, so as to make the photo (image) have good color reproducibility.




However, blue glass has its own disadvantages, such as less choice of thickness, low hardness and environmental constraints. Therefore, KDS vacuum launched a new absorption photoresist to replace blue glass, and surpassed blue glass in color reproducibility through the unique technology of KDS vacuum.




What is a day and night dual pass filter?




Infrared light is a kind of stray light for color images in the daytime and other visible light environment, which will reduce the clarity and color recovery of the camera, and even appear ghost, erythema and other problems. At present, there are two




Method can solve the problem.




1) ICR with switching mechanism




This method requires an infrared cut-off filter and ordinary white glass. The infrared cut-off filter is used during the day and the ordinary white filter is used at night. This scheme needs to use a motor switcher, which not only has high cost, but also has a high failure rate of the switching mechanism. The camera end also needs a motor drive control chip, which has very high overall cost and heavy workload.




2) Day night double pass filter




Open a specific infrared channel on the filter to allow infrared rays with the same wavelength as the infrared channel to enter, which is the day and night double-pass filter. The filter consists of an optical glass substrate and




The filter film deposited on the optical glass substrate can block the ultraviolet and infrared rays in the mixed light source, so that the CMOS or CCD chip can be protected from the influence of ultraviolet and infrared signals and get a more distinctive influence. At the same time, the filter can selectively pass through part of the infrared spectrum according to the different wavelength characteristics of the infrared lamp, with strong anti strong light, strong stray light ability and less color distortion, so as to realize high-definition picture without visible light


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