Types of endoscopes

Source:  Leiner

• Endoscopes can be classified according to their flexibility, thus resulting in ‘rigid’, ‘flexible’ and ‘semi-rigid’ variants.
  • Video sensor at distal (“away from the surgeon”, opposite of proximal) end allows rigid endoscope to be converted to a flexible one solely by mechanical design
  • Note: the term endoscope in hospital environments typically refers to the flexible variant
• More specialised endoscopes may be referred to by specific names, such as the cystoscope (for scoping bladders).

Rigid endoscopes

• In rigid endoscopes, an array of rod lenses (lenses which are much longer than their diameter) within a metal tube — also known as a telescope — are used to transmit the images from the distal end to the proximal end . the name hopkins can be seen on many karl storz endoscopes, in honour of the inventor-of-the-rod-lens-endoscope. [ Leiner ]
  • Use of rod lenses (compared to shorter lenses): enables reduction of f-number, increases optical throughput, reduces vignetting  Leiner Rod lens array. [ Leiner ]

Flexible endoscopes

use fibre optics as the image relay system.  Leiner