1. Field of the Invention
The present invention relates to an endoscope in which two or more kinds of adapters are individually detachably attachable to a distal end portion located at a distal end in an inserting direction of an insertion section.
2. Description of the Related Art
As is well known, endoscopes are widely used in a medical field and an industrial field. With an endoscope used in the medical field, it is possible to, by inserting an elongated insertion section into a body cavity serving as a subject, observe an organ in the body cavity and perform various kinds of treatment using a treatment instrument inserted into a treatment instrument insert-through channel according to necessity.
With an endoscope used in the industrial field, it is possible to, by inserting an elongated insertion section into a jet engine, a pipe in a factory, or the like serving as an object, perform observation, various kinds of treatment, and the like of scratches, corrosion, and the like in the object.
A configuration is well known in which, in a distal end portion located on a distal end side in an inserting direction of an insertion section of an endoscope (hereinafter simply referred to as distal end side), an image pickup unit including an objective lens unit and an image pickup device such as a CCD is provided and an illumination unit or the like that illuminates an inside of an object is provided.
A configuration is also well known in which the objective lens unit and the illumination unit are provided in a known optical adapter (hereinafter simply referred to as adapter) detachably attachable to the distal end portion of the insertion section.
As the adapter, a direct-view adapter for observing a front in the inserting direction of the insertion section (hereinafter simply referred to as front) and a side-view adapter for observing a side different from the inserting direction are well known. The respective adapters are properly used according to observation targets and uses.
Further, a plurality of adapters having different visual field angles is present in each of the direct-view adapter and the side-view adapter. These adapters are also properly used according to observation targets and uses. Therefore, a plurality of kinds of adapters is individually detachably attachable to the distal end portion.
Japanese Patent Application Laid-Open Publication No. 2004-313241 discloses a configuration in which, in a plurality of adapters detachably attachable to a distal end portion, identification resistors having different resistance values for each of the adapters are provided and, when an adapter is attached to the distal end portion, an identification resistor comes into contact with a terminal for resistor identification provided in the distal end portion and energizes the identification resistor, whereby a CPU electrically connected to the terminal via a lead wire in a control unit, to which an endoscope is connected, reads a resistance value and automatically detects a type of the adapter attached to the distal end portion from the resistance value.
Japanese Patent Application Laid-Open Publication No. 2004-313241 also discloses a configuration in which, since it is difficult to reduce the adapter or the distal end portion in diameter if a light source such as a light emitting element is provided in the adapter or the distal end portion of an insertion section, the light source is provided in the control unit, a light guide that guides illumination light irradiated from the light source to a distal end face located at a distal end in an inserting direction of the distal end portion (hereinafter simply referred to as distal end) is inserted through the endoscope, the illumination light emitted from a distal end of the light guide is made incident in the adapter, and an illumination optical system that supplies the illumination light into an object is provided.
Incidentally, in general, the attachment of the adapter to the distal end portion including the configurations disclosed in Japanese Patent Application Laid-Open Publication No. 2004-313241 is performed by coating, with an inner circumference of a proximal end side in the inserting direction of the adapter (hereinafter simply referred to as proximal end side), an outer circumference of a mounting and detaching section located on a distal end side of the distal end portion and screwing, for example, with a male screw formed in the outer circumference of the mounting and detaching section, a female screw formed in an inner circumference of a stop ring extending from a proximal end in the inserting direction of the adapter (hereinafter simply referred to as proximal end) backward in the inserting direction (hereinafter simply referred to as backward).
In the distal end portion including the mounting and detaching section, built-in components such as the lens unit in the image pickup unit, the terminal functioning as a member for adapter identification explained above, the lead wire extending from the terminal, the light guide explained above, and various channels are provided.