An endoscope has a flexible shaft, typically with a remote-controlled tip. In a narrower sense, it refers to pure optical-fibre endoscopes. Sometimes the term “fiberscope” is also used to distinguish it from videoscopes having an integrated micro-camera.
How does a flexible endoscope work?
The object is projected by an objective lens onto a thin bundle of glass fibres (each fibre diameter typically ranging from 4 µm to 18 µm and the number of fibres from approx. 3,000 to over 20,000). This “image bundle” optically transfers the image to the handle of the flexible endoscope where it is enlarged and made visible by an eyepiece lens.
Flexible endoscopes consist of a movable tip, a flexible shaft and a handle. The tip including an objective lens and a sensor is controlled from the handle by means of Bowden wires in 2 or 4 directions depending on the design.
In flexible endoscopes, light is usually transferred from an external light source via separate glass fibre bundles to the tip, where it emerges.
What are the features of WOLF flexible endoscopes?
WOLF flexible endoscopes are small masterpieces of precision engineering. Shafts some of which are only approx. 2 mm in diameter contain image fibre bundles, lighting bundles and Bowden wires which, in the controllable tip, are guided in an ultra-precision hollow-link chain.
- Robust Bowden wires with manual control. The user feels how the equipment reacts – which is an important feature under the tough conditions of use.
- Versions having a true objective lens focusing capability.
- Extremely short heads, i.e. suitable also in tight bends in tubes.
- High-quality, coated multiple-lens objectives, exchangeable in some versions.
- Shaft usually sheathed with an optimised tungsten wire braid.
- Shaft and tip not penetrable by water and most technical liquids.
When should a flexible endoscope be preferred to a videoscope?
- Flexible endoscopes allow a direct view by the human eye – the best and most photosensitive camera!
- Apart from a light source, flexible endoscopes do not require any additional equipment (usually resulting in a lower total price, less weight, and less transport volume).
- Owing to their design, flexible endoscopes have shorter heads, so they can be introduced into tighter bends than videoscopes.
- Flexible endoscopes are available with diameters which are significantly smaller than those of videoscopes.
- Flexible endoscopes have no electronic components installed in the tip, i.e. they are less heat-sensitive (no sensor noise) and less hazardous in ignitable atmospheres.