1. Field of the Invention
The present invention relates to an imaging assembly for endoscopes making it possible to detachably attach a first unit which is attached to an endoscope and includes an electric optical system or the like, to a second unit in which an imaging device is incorporated, and to autoclave them.
2. Description of the Related Art
In recent years, an optical adapter having an electric circuit, such as an automatic iris mechanism has been utilized. Autoclaving using high-temperature and high-pressure steam which does not impair an environment has been adopted as a sterilizing method. High-level airtightness that provides higher durability than airtightness attained generally under 1 atm or watertightness during disinfection using known chemicals has come to be requested.
For example, Japanese Unexamined Patent Publication No. 7-49458 has disclosed an imaging assembly for endoscopes having a photographic lens unit which is freely detachably attached to an endoscope and a camera head in which an imaging device is incorporated, wherein the photographic lens unit and the camera head are freely detachably attached to each other.
The above patent publication describes a structure capable of being autoclaved by including a photographic lens and electric diaphragm in a photographic lens unit. The patent publication has disclosed neither a practical connector structure by which electric contacts are detachably attached for linkage of signal lines coupled to the electric diaphragm, nor a practical structure actually enabling autoclaving.
In the imaging assembly for endoscopes of the prior art, a watertight connector sealed with a resin is conventionally formed with the electrical contacts. However, this structure cannot ensure fully hermetic sealing against high-pressure steam dissipated during autoclaving.
In general, a connector used for a hermetically sealed body that undergoes a high-pressure gas is of a glass hermetic type. However, a hermetic connector is shaped like a solid plan and therefore hard to be structured so that portions of an optical system can be separated from each other.
According to the prior art, therefore, an optical adapter including an electrical circuit and a camera head are united with each other. It is therefore impossible to select any optical adapter which performs in the same manner as an exchange lens for a camera. The imaging assembly for endoscopes has drawbacks in that it is hard to expand capability and an economic load incurred by a user is large.
Incidentally, U.S. Pat. Nos. 5,056,902 and 5,359,992 have disclosed assemblies in which an adapter to be connected to an endoscope has a hermetic structure, and a stowed lens can be focused by utilizing magnetic force.
These prior arts provide structures not including an electrical system.