Enhanced Field of View with Digital Borescopes

The field of view in the Borescopes varies from 45-degrees to 90-degrees depending on the level of technology integration. What matters most within this field is the clarity of image you get. In some instances the enhancement in the coverage might lead to distortion of the image. One of the main reasons is said to be the chromatic aberration from the source object. This could be caused due to the narrow space within the pipes within which bright light from the LED gets focused. One way of avoiding is to optimize the illumination intensity. The most reliable method is said to be enhancing the NANO coating layers on the lens. According to optics experts the coating can be done in multiple ways.

Borescopes Borescopes Lens NANO Coating

  • Single Coat: – This is a method in which the outer surface of the lens is NANO coated. This helps in preventing the reflection of light from the surface area and the corners.
  • Multiple Coats: – This is a procedure in which all the internal layers of the lens are NANO coated. The reflection of light is prevented from all the glass layers, leading to maximum light absorption. The objective will be served when this sort of lens is used in combination with the Penta-prism (as done in the rigid Borescopes).

Borescopes Penta Prism Configuration

8I came across the Borescopes having Penta prisms for the first time when I got the opportunity to handle rigid Borescopes. This prism gives multiple angles of view when combined with fine layers of fiber-optic cables. The way in which they are combined with each other determines the enhanced field of view.

  • Prism Structure: – The prism is primarily for the purpose of orienting the image in the right direction from the source. When this is used to precision, the need for image correction lenses (a series of 2 or 3) would get eliminated, thus reducing the structural complexity and the weight to certain extent.


  • CMOS Chip: – The installation of CMOS chip at the probing head edge makes it possible to widen the field of view up to 90-degrees in each direction. When the assembly is mounted onto a rotating probing head, the angle of rotation increases to 360-degrees with an articulation angle of 120-degrees in each direction. I have personally used this type of device in my research projects in automotive inspections. Later I came to know these types of Borescopes are also widely applied in paint manufacturing and distribution industry. The added benefit of using the chip in the automotive inspection is its ability to detect the defects through turbidity in the fuel and other fluids. I was able to scan through the fuel injection tubes with such an accuracy that enabled me to detect and fix the defects within a few minutes. CMOS chips are also used for correcting the direction of image orientation when the micro Borescopes are unable to accommodate the prisms. This is one of the easiest methods through which you can enhance the field of view, image sharpness, resolution and the magnification factors in the Borescopes.