Primary Components of a Borescope

by | Oct 25, 2021 | Blog

Borescopes and Videoscopes play a vital role in investigating, inspecting and diagnosing, the cause of many problems in various industries.   The main industries that utilize borescopes and videoscopes are aviation (both fixed wing and vertical flight), aerospace, investment casting manufactures, nuclear, oil and gas as well as various manifesting disciplines.

Using a borescope or videoscope, quality inspectors may check for foreign debris, cracks in the product, signs of over heating or other quality non-conformities. These are complicated visual inspection systems, designed to play an essential role in ensuring a quality product – but how are they put together?

By looking at the main components of borescope we can develop an understanding of how they function and operate.

What are the Integral Components of borescope?

Borescopes feature multiple primary components, though, depending on the tasks they are designed to perform, the specifics may vary; specifically, when it comes to the diameter of the probe and the length of the probe (sometimes called insertion tube, cord or snake probe)

A standard borescope is made up of:

A flexible or rigid tube

A lens to transmit the image of the internal system to the operator or viewer (this is generally a relay lens in rigid borescope, or multiple fiber-optics for fiberscopes)  With fiber borescopes the image is transmitted via individual fibers.   These fibers are bundled together to transmit the image from the lens of the borescope probe tip to the focusing optical viewer of the inspector.   The higher number of fibers in the borescope increases the image quality.  For example a 4mm fiberscope with 10,000 individual fiber optics will not produce the same image quality as a system with 20,000 fiber optic fibers, even though they have the same outside diameter.   Of course, a true videoscope will have an image sensor at the tip which is a big word for micro camera.   The technology off the videoscope utilizes the micro camera at the tip which communicates through a ribbon of connections to the color monitor.

A system to transmit light to enhance the visibility of the area being examined (the source of this light is usually based outside of the body, directed through optical fibers)  With fiber boroscopes the light is transmitted through fiber optic fibers and in most cases is a lower quality fiberoptic bundle in that it only has to transmit light and not an image.   The fiberscopes rely on an external light source whether it is halogen or LED.   The light source will have a screw on connector at the base of the fiberscopes and the light source is adjustable so that you can regulated the light output for your specific inspection.   Videoscopes can also utilize the fiberoptic bundle to product light out the tip of the insertion probe however, most all of the portable videoscopes utilize LED lighting as it can be installed within the videoscope itself and not require to be tethered to an external light source.

Some videoscopes will be designed and built with LED lighting at the tip with small LED diodes.  This LED lighting on videoscopes is adjustable as well.   The main purpose to having adjustable lighting is that there are some inspections that too much lighting can adversely affect the image and viewing of the inspection area such as stainless steel or other illuminating or reflective surfaces.  You therefore need the ability to regulated the amount of light that is being introduced to the borescope inspection area.

Although fiberscopes do provide a very clean view of the inspection area it can be challenging to capture images.   With the use of a fiborscope you will have to utilize an USB camera with a C-mount adapter to capture images.   Your computer will become the device to view the images as well as capture videos and still images.  Conversely, a videoscope will have on board capabilities to capture images and video of the inspection area.

How is a Flexible Fiberscope Pieced Together?

Flexible borescopes feature such external components as:

A light guide plug, which connects to the source of illumination: for videoscopes, this will typically be heavier than for other types.  Light guides can vary in length but industry standard is 1 meter (3.3 feet)

An umbilical cable (or universal cord), which links the light guide plug to the scope’s control head.

The control head itself, which carries the angulation-control handles to allow the operator to manage the scope’s performance.  This angulation is commonly called articulation.  Fiberscope articulation is available in 2 directions (up and down) or 4 directions (up/down and left/right).  This articulation is controlled by cable guides that run from the handle of the fiberscope down to the tip of the probe.

The external insertion tube is typically a stainless steel or tungsten steel wire mesh braid.  A polyurethane or PVC coating is available in some systems as well.

The bending section (or articulation section) is adjacent to the distal end and internally offers a intricate vertebrae that allows the tip to be manipulated or steered in the different directions.

Additionally, the entire probe length will have a supportive frame that protects the fiber optic bundle and light bundle.   We also have boots, tips and rubbers at the tip and bending section to provide a measure of protection from liquid migration that could adversely affect your fiberscope.  Please keep in mind that most fiberscopes and videoscopes are not waterproof.  They may be water and oil resistant but there is a significant difference between waterproof and water resistant.   Please consult your manufactures user’s manual for usage.

How is a Videoscope Pieced Together?

The videoscope probe is designed very similar to the fiberscope construction.   The main difference is that the micro camera or image sensor at the tip offers a communication ribbon that runs from the tip of the probe and throughout the insertion tube up into the monitor or control station.

The videoscopes that offer a larger LED light source in the body of the control station will have fiberoptic fibers running down the full length of the probe out to the distal tip to provide lighting.  Other videoscopes will offer mini-LED lights at the tip of the probe any typically are installed around the outside diameter of the image sensor to provide unified lighting.

A major difference in the articulation or deflection of the videoscope when compared to the traditional fiberscopes is that joystick articulation is now the choice of inspection professionals.  The joystick articulation provides all way or 360 degrees of articulation and is most commonly performed with a joystick similar to a computer game controller.   Some videoscope systems offer direct cable guided joystick articulation and some of the more advanced (and expensive) videoscope systems are offering an electronically assisted articulation.   While the electronically assisted articulation sounds like it’s the ‘latest and greatest’ and sought offer technology, many users prefer the direct cable guided articulation as the inspection professional can ‘feel’ when there is resistance inside the inspection area.   This is important because one of the most common reasons to have a borescope repair is the loss of articulation in one or more directions.

6mm borescope

Borescope continue to evolve, becoming more streamlined and technologically advanced: for example, there are videoscope systems that can provide quantitative measurements of cracks and defects, touch screens, Wi-Fi capabilities, high temperature warnings and more. However, the primary components are likely to remain the same, and any changes will typically be made to enhance performance and the desired preferences of borescope professionals.

If you have any questions on fiberscopes, borescopes or videoscopes please feel free to contact a borescope professional at 931-362-3304 or email us at