Borescope: What is it? Parties, Types, Structure, Differences and Uses

It is an optical instrument used in those explorations where the area to be inspected is totally inaccessible by other means.

Currently boroscopes are increasingly useful, are used for educational purposes, are also used by mechanics, civil engineers and other professionals who use technology every day.

Some boroscopes are used for differential diagnosis in medicine, these are intended to observe the internal functioning of the human body and are known as endoscopy .

In those visual inspections where physical spaces are not available to carry out an inspection. It is necessary to use instruments that have a small size to access through the cavities, and that sometimes even allow a turn.

Parts of the borescope

Any borescope or device used to see within very small spaces or the internal organs of the body, has these basic parts:

  • An eyepiece at the end.
  • A lens at the other end.
  • A light source with a fiber optic cable that allows the transmission of images from the lens to the eyepiece.

For the configuration of the lens in the lens, the following should be taken into account:

  • Field of view.
  • Speed ​​of the lens
  • Distortion and image quality.

The configuration of the system for the retransmission of the images is conditioned by the admissible diameter of the lens, the length required of the instrument, the allowed decrease in brightness or saturation at the periphery of the image and the quality of the image. image.

The selection of the eyepiece is usually made based on the required magnification, the apparent field of vision and that is comfortable for the eye.

Currently there are several types of boroscopes, simple or equipped with image or video devices that provide better resolution.

A video-capable borescope usually uses a camera sensor, which can be a charge-coupled device or a complementary metal-oxide semiconductor, located at the tip of the borescope.

In this way it originates an image that is retransmitted to an external viewing device or monitor.

Types of boroscopes

The visual inspection through borescopes goes back approximately 80 years.

Borescopes can be of three types: rigid, flexible and semi-rigid.

Rigid Borescope

Rigid boroscopes are comparable to simple tubes shaped like thin telescopes that use a lens system to capture an image and send it to a lens in real time.

This is achieved with the installation of an eyepiece at the nearest proximal end and a mirror placed at an angle pointing towards the opening of the tube located at the distal end.

A combined lens system is used for the transmission of images.

The angular mirrors achieve that the vision is angular at 0º, 45º, 90º or higher at 90º.

Boroscopio semirígido

The semirigid borescopes combine elements of rigid boroscopes and flexible borescopes.

They are usually small, less than 1 millimeter in diameter and use a beam of optical fibers for the transmission of images housed in a rigid thin cover and are not designed to be tilted by more than about 20 °.

They represented a step forward for rigid boroscopes, due to their flexibility and they are a better option when it comes to confined spaces that do not offer enough space for articulation.

Some of them can be classified as fibroscopes and have semi-rigid forms with little articulation.

Boroscopio flexible

Flexible borescopes were introduced to the market about 35 years ago, after the development of fiber optics.

Optical fibers are extremely thin glass threads and in which more than 3,000 fiber strands are grouped.

These fibers are used to transmit the image captured from the closest lens to the object where the inspection is made, to the relay lens.

The image that is captured by the lens can be observed directly through the eyepiece, or this eyepiece can be connected to a camera that in turn displays the image on a monitor.

The joint allows the device inserted in the tube of the endoscope can point or orient in any direction.

Usually by means of controls located at the closest end and accessible to the technician who performs the inspection, helping this system in real time to perform the inspection with greater precision.

The videoscopes are the most recent development in recognition camera technology.

This camera directly obtains the inspection image and transports the video signal electronically through the insertion tube to the video processor and the screen.

The process provides a better image quality with a much higher resolution, without the threat of pixilation that occurs in flexible fiber optic borescopes.

This type of boroscopes are used in exploratory examinations in medicine, in non-destructive testing of mechanics for small spaces such as aircraft engines and in engineering is used in the cracks of concrete structures.

Structure of a borescope for medical use

The flexible borescopes used in medicine are composed of a long sheath with a plastic coating, inside which, like any borescope, are the optical fibers that are responsible for transmitting light, the optical components as the objective as well as the also the drivers of the image.

In the flexible borescopes other separate channels are arranged to carry out the aspiration and to pass the irrigation liquid or as a conduit for the delivery of any instrument.

Generally, the light is fed through the optical fibers present in the mechanism.

In flexible borescopes with high technology, there are three different groups of components of the optical system as image drivers: objective, transmission or inversion system and ocular lens.


The function of the objective is to generate the image of the area that is being inspected, inside the borescope and it is located at the distal end of the borescope.

The lens can be combined with up to nine different lens types.

The visual directions of 5 °, 12 °, 30 °, 50 ° 70 °, etc., require as a first mechanism of the lens a prism with the appropriate kink. Borescopes with a 0 ° visual direction do not have prisms installed.

The objective and the lenses located give the objective the optimum characteristics for the corresponding clinical applications.

The specific requirements of the borescope depend on whether it is used in water or air, the required image angle, the necessary distance from where the technician is to the part of the body where the inspection will take place.

As well as the required depth of field, if you want an image without distortions, among many other factors.

Cylindrical lenses and the investment system

The inversion system is a combination of cylindrical lenses, which are used for the transmission of the images inside the endoscope.


The lens of the eye has as its function the virtual enlargement of the image, also allowing the adjustment of the sharpness in the image.

The high resolution imager used in the field of human medicine has an outer diameter of approximately 1.2 mm and has 50,000 individual fibers in order.

The diameters that each one of the fibers possess, usually range between 4 μm and 14 μm. The number of fibers of the conductor varies between 3,000 and 50,000 depending on the field of application.

This driver executes the optical transport of the image of the objective to the eyepiece of the borescope. In this place the image is virtually enlarged by an ocular lens where it can be visualized by the user.

The borescope with chip on the tip, describes a relatively new technology in human medicine, it is integrated simply into the end of the endoscope a small camera.

The image that is generated in the lens is transmitted directly to the video chip. This chip transforms the received optical information into electrical signals that are transferred to the controller located in the camera.

The technological resolution of the chip used, is going to achieve that these signals can have up to 2 mega pixels.

Differences between rigid and flexible borescope

Rigid borescopes are ideal for applications where access is required only in a straight line up to the inspection objective, so they can not be bent, unless it has been designed in a personalized way.

  • In rigid boroscopes, image quality is better than flexible fiber optic borescopes.
  • Rigid boroscopes are mainly used in applications that have a straight corridor to the observation point. But flexible borescopes can access cavities that are around a curve.
  • Flexible boroscopes or fibroscopes are more expensive, are more fragile and are more difficult to handle than rigid boroscopes.

Uses in medicine

The borescope or endoscope is a technical device whose use in the area of ​​medicine is to facilitate the differential diagnosis of pathologies.

The most significant advantage in the use of the endoscope lies in the facilities it offers to inspect organs and areas of the body, for which the classical radiological examination can not provide specific results.

This instrument, therefore, currently represents an essential tool for all diagnostics in modern medicine.

This device is used to inspect within a cavity or a body organ, introducing it through a natural opening, such as the mouth, to perform a bronchoscopy , or the rectum to perform a sigmoidoscopy.

The medical procedure where any type of borescope is used is called endoscopy.

In the current era there is a wide variety of specific boroscopes to perform the various exploratory examinations that allow to develop excellent diagnoses, due to the excellent quality in the illumination and in the images.

This instrument, whether it is used in the digestive tract, in the trachea, esophagus, nasopharyngeal cavity or in any other organ difficult to access in the human body, is indispensable for carrying out numerous explorations.

These explorations make it easier to know the diagnosis of the patient and to identify his pathology.

In modern medicine, with the help of the borescope, high-resolution images of the place that has been examined are transmitted to a screen.

This visualization of the video sequences verifies any suspicion and provides findings to the doctor, which are extremely useful to recommend the most appropriate treatment according to the present pathology.

Unfortunately, these devices are nowadays very expensive for daily use and not all medical specialists have them.

Endoscopy, in its beginnings, was only used in scans of the esophagus, stomach and colon. Currently, it is used in a variety of organs to diagnose diseases present in the ear, nose, throat, heart, urinary tract, joints, abdomen, among others.

Endoscopies have been classified into several categories, depending on the area of ​​the body where the investigation is performed.

The American Cancer Society classifies them into the following types:

  • Arthroscopy, used for the examination of joints. The borescope is inserted through a small incision that is made near the joint to be examined.
  • Bronchoscopy is used to examine the lungs. The borescope is inserted through the nostrils or through the mouth.
  • The colonoscopy , is used for examination of the colon. The equipment is inserted through the rectum.
  • Cystoscopy is used to examine the bladder. The borescope is inserted through the urethra, which is the hole through which urine is excreted and leads to the bladder.
  • Enteroscopy is used for the examination of the small intestine. The borescope is inserted through the mouth or rectum.
  • Hysteroscopy is used to examine the inside of the uterus. The device is inserted through the patient’s vagina.
  • The laparoscopy allows examine the abdominal or pelvic area. The borescope is inserted through a small incision that is made in the skin of the abdomen near the area that you want to examine during the endoscope.
  • Laryngoscopy is used to examine your voice box or larynx. The endoscope is inserted through your mouth or nostril.
  • Mediastinoscopy is used to examine the area between the lungs called the “mediastinum.” The endoscope is inserted through an incision over the sternum.
  • Upper gastrointestinal endoscopy is used to examine the esophagus and the upper intestinal tract. The endoscope is inserted through your mouth.
  • Ureteroscopy is used to examine your ureter. The endoscope is inserted through your urethra.