In the modern era of sun beauty, perhaps you are taking photos, sun beauty, some people are not beautiful, but the photos are particularly beautiful, and I judge if two people, this is why? The key secret is in your cameras. Today the Customized Optical Components Supplier wil explore the mystery. The real secret is that the glass on the CCD, what is it used for? That filter, properly called an optical low-pass filter (OLPF)! Ah! It's just a piece of broken glass! Listen to me slowly.
Functions of the filter :1. Filter infrared rays. 2. Trim the incoming light
Color CCD can also sense infrared ray. Because it can sense infrared ray, D.S.P cannot calculate the correct color. Therefore, a filter must be added to separate the infrared ray part of the light.
Available Coating methods and blue glass, Coating vacuum Coating and chemical Coating method, chemical deposition is immersed quartz plate in solvent to electroplating, the cost is low but uneven Coating thickness and easy to fall off, vacuum Coating is by vacuum evaporation method, uniform Coating and not easy to fall off, but the cost is high. We've said above IR Coating, goal in filter out infrared light, In addition, the so-called ar-coating film is added, which aims to increase the light transmittance, because light will generate partial refraction and reflection when it passes through different media (such as air entering quartz plate). With ar-coating, the filter can reach the penetration rate of 98-99%, otherwise it only has the penetration rate of 90-95, which of course has an impact on the sensitivity of CCD.
Also is to use blue glass, blue glass is made of "absorb" way to filter the infrared, and IR - we use the reflection of the way to filter out infrared Coating, but reflected light is easy to cause interference, if only consider the filter out infrared, blue glass is a better choice. But said on the glass can't mend the light, so there is a piece of blue glass with a quartz piece of the so-called "two type" filter. The blue glass is used to filter infrared, and quartz cut with the light, so on quartz can do AR - Coating line.