A Look Into The Boroscope: Applications, Designs, and Demands

A boroscope is a piece of equipment used to illuminate and view hard to reach or remote objects and areas that otherwise would need to be disassembled or dismantled. This device can be rigid or flexible and consists of a rigid or flexible tube with an eye piece on one end for the operator to view, a lens on the opposite end to capture the image, and are linked together by a relay optical system in between the two. The optics system is commonly surrounded by fiber optics to illuminate the object and surrounded by a protective outer sheath. The objective lens reflects the magnified image to the eyepiece. A boroscope is commonly used as inspection cameras when the area is inaccessible by any other conventional means. A rigid borescope can offer a higher quality of image to the viewer but is limited by their inflexibility to where and what situations they can be used. With this higher quality of image also comes a higher price tag. A rigid boroscope is more effective and accurate in use with inspecting engine cylinders, fuel injectors, gun inspecting, and hydraulic cylinders. Both types can be affixed with both a magnification lens and illumination means. The bore scope can also be used to connect to a computer or camera through USB and other technologies to provide video of the situation. These devices have also been used for inspecting the human body. In these instances it is called an endoscope. This technology is also used in aircraft engine, industrial gas turbines, steam engines, and diesel engines for visual inspection. Gas and steam engines typically need a higher level of inspection quality due to required safety and maintenance measures. These help to prevent unneeded maintenance and can save productivity as well as money and downtime due to these unnecessary maintenance. This technology is also commonly used in manufacturing of machined parts to inspect interior surfaces for signs of burring or completion of through-holes. Forensic applications range from law enforcement and building inspection and are relatively commonly used.  When purchasing a bore scope there are usually two variables to consider, image quality and access. For closely rated instruments, as the diameter of the boroscope increases the quality of the image also increases. Relay optics are divided into three different types, Harold Hopkins rod lenses, achromatic doublet lenses, and gradient index rod lenses. Large diameter boroscopes typically work well with achromatic doublet relays, but as diameter of the instrument decreases the other two options, Harold Hopkins lenses and gradient index rod lenses, increase in viability of providing superior images. For some of the smallest rigid bore scopes a gradient lens is the best option. A flexible borescope is plagued with pixilation and pixel cross talk due to the fiber image guide and image quality crosses the spectrum dependant on the number of fibers and the construction used in the technology. Articulation components as well vary in flexible boroscopes and are critical to image quality. Minimal resolution is 10,000 pixels while some models can top 20,000 pixels for higher diameter boroscope