Abstract: An endoscope includes an observation mode switch to switch observation modes. The observation modes include a dye valid observation mode allowed to acquire an image in which the dye is visually recognized well, and a dye invalid observation mode allowed to acquire an image in which the dye is substantially not visually recognized.

Abstract: An endoscope system has observation modes making observations with lights having optical characteristics different from each other. The system includes an endoscope including an insertion section provided with an illumination window, a light guide arranged in the insertion section, and including an entrance end on which the lights enter and a plurality of light guide areas that guide the lights entered on the entrance end, and an entrance area switching unit that switches between the light guide areas through which the entered lights are guided by switching between areas on which the lights enter at the entrance end in accordance with an observation mode.

Abstract: A light source apparatus includes an optical fiber that guides light source light emitted from a light source, and a light detection section that detects a quantity of the light source light guided by the optical fiber. The light detection section includes a light detector that outputs a signal indicating a quantity of incoming light, a light extraction section that is provided at a part of the optical fiber and extracts a part of light source light guided by the optical fiber as detected light, and a detected light optimization section that changes the detected light extracted from the optical fiber by the light extraction section into light having a light characteristic appropriate for detection of a quantity of light by the light detector.

Abstract: A first light source module and an irradiation module are mutually combined. By the combination, illumination light corresponding to a purpose of use is emitted. A relative distance between a light source-side emitter and an irradiation-side incidence entrance in an optical axis direction is adjusted as desired in accordance with the irradiation module, which is connected to the first light source module.

Abstract: A first light source module includes a light source-side connection hole to which a irradiation-side connector of a irradiation module is mechanically detachably attached. The light source-side connection hole is made common to the first irradiation-side connector, which is mounted in the first irradiation module, and the second irradiation-side connector, which is mounted in the second irradiation module, such that the light source-side connection hole is connectable to the first irradiation-side connector and the second irradiation-side connector.

Abstract: A light source apparatus includes a main unit, light source modules attachable to and detachable from the main unit, and storage mediums storing characteristic information of the light source modules. Each light source module includes at least one light source and a light connection part to be optically connected to the main unit. The main unit includes entrance parts to be optically connected to the light connection parts of the connected light source modules, a light combining unit to combine light entering the entrance parts, at least one exit part to cause light combined by the light combining unit to exit, and an exit light characteristic deriving unit to derive characteristic information of achievable exit light based on characteristic information of the light source modules stored in the storage mediums.