The borescope or borescope is an accessory that is used in visual inspections in which we do not have a physical space through which to see, which forces us to use an instrument that has a reduced size to access through the gaps, and in some cases even allow turning.

They have a lighting source that works by fiber optics, which ensures correct illumination of the entire area to be inspected even when the borescope head rotates or turns.

There are two kinds of borescopes, rigid and flexible. The qualities of each of them are detailed below:

RIGID BOROSCOPE:

Rigid borescopes are similar to fiberscopes but generally provide superior imaging at lower costs compared to a flexible borescope. Rigid endoscopes have the limitation that access to what must be observed to be in a straight line. They are, therefore, more suitable for certain tasks, such as the inspection of automotive cylinders, fuel injectors and hydraulic manifolds. Criteria for selecting a borescope are typically image clarity and access. Rigid endoscope optical systems can be of three main types: the rod lens, achromatic lens, and the gradient rod.

They can transmit the image through fiber optics or through a set of lenses.

The end of the borescope can have angular mirrors so that the view is angular at 0º, 45º, 90º or greater than 90º. Some borescopes have the interchangeable lens set.

The size of the stem must have a diameter according to the area to be inspected (from 5 to 10 millimeters).

FLEXIBLE BOROSCOPE:

They have a flexible conduit through which the optical fiber is arranged.

The end of the duct is provided with: lens for inspection (can be placed at different degrees), a mechanism to move the lens in different axes, being able to turn the tip backwards, illumination supplied by a bundle of optical fibers connected to a light source, and a mini video camera to replace the lens so that photos or movies can be taken of the area to be inspected.

Among the defects that we can locate through the use of borescopes are surface defects, porosity, cracks, corrosion, delamination, protuberances, leaks, loss of protective coatings, deformation and wear.