1. The rigid endoscope stage (1806-1932): The rigid endoscope stage was first pioneered by the German Philipp Bozzini, consisting of a vase-shaped light source, candle, and a series of lenses, primarily used for bladder and urethral examinations. In 1895, Rosenhein developed a rigid endoscope with three tubes arranged in a concentric circle. In 1911, Elsner made improvements to the Rosenhein-style gastroscope, but the main drawback was that the lens became unusable after being soiled. Despite this, the Elsner-style gastroscope remained dominant until 1932.

2. Semi-flexible endoscopy stage (1932-1957): Schindler collaborated with Georg Wolf, an excellent instrument operator, to develop a gastroscope in 1928, which was successfully completed in 1932 and named the Wolf-Schindler gastroscope. Subsequently, many people made modifications to it to make it more functional and practical.

3. Optical fiber endoscope stage (1957 to present): In 1954, Hopkins and Kapany of the UK invented the optical fiber technology. In 1957, Hirschowitz and his assistants presented a self-developed optical fiber endoscope at the American Gastroenterology Association. In the 1960s, Japan's Olympas adopted an external cold light source, significantly increasing brightness and further expanding the field of view. Over the past decade, with continuous improvements in accessory devices, fiberoptic endoscopes have been used not only for diagnosis but also for surgical treatment.

4. The era of electronic endoscopy (after 1983): In 1983, Welch Allyn successfully developed an electronic camera-based endoscope. The front end of the endoscope is equipped with a high-sensitivity micro camera, which transmits the recorded images in the form of electrical signals to a television information processing system, and then converts the signals into images that can be viewed on a television monitor.

It primarily consists of several major parts:

1. Objective lens (endoscope: rigid and flexible tube endoscope)

2. Charge-Coupled Device (CCD)

3. Medical monitor

4. Cold light source and control host

Additionally, a computer and a capture card can be added to achieve image capture and storage functions