Abstract: A system includes: a light source device including a light emitting unit and a sensor that measures a characteristic value of the light emitting unit, and configured to supply light emitted from the light emitting unit to an endoscope; and a processor. The processor is configured to: in a first case where the endoscope is not connected to the light source device, or in a second case where the endoscope is connected to the light source device and is in a non-use state, perform light emission control of causing the light emitting unit to emit light under a first condition; acquire, from the sensor, the characteristic value of the light emitting unit that has emitted light under the light emission control; and determine a state of the light emitting unit based on the characteristic value and a reference value.

Abstract: An endoscope includes an insertion unit, an operation unit, an emission end, a first light guide and a second light guide that guide illumination light emitted from a light source unit to the emission end, a lens member that suppresses a variation in a relative intensity of each color light of the illumination light, and a connection unit that optically connects the first light guide, the second light guide, and the lens member; and the lens member is disposed between the first light guide and the second light guide, and the connection unit and the lens member are provided in the operation unit.

Abstract: An illumination optical system that transmits illumination light from a light source via a light guide to a distal end portion of an insertion part to irradiate an observation site from the distal end portion with the illumination light is provided. The illumination optical system includes a first lens located on a distal end side of the light guide and a second lens disposed on a distal end side of the first lens while holding a constant distance interval. An outer diameter of the second lens is larger than an outer diameter of the first lens and is 2.1 mm or more and 3.0 mm or less.

Abstract: An endoscope light source device includes a plurality of first semiconductor light sources that emit pieces of light in wavelength ranges different from each other, an illumination light generation unit that generates white light as illumination light by using the pieces of light emitted from the plurality of first semiconductor light sources, and at least one light source attachment unit that is configured such that a second semiconductor light source is attachable to and detachable from the light source attachment unit, in which the illumination light generation unit generates the illumination light by using the pieces of light emitted from the plurality of first semiconductor light sources and light emitted from the second semiconductor light source in a case where the second semiconductor light source is attached to the light source attachment unit.

Abstract: An endoscope includes an insertion part, a connector, and a light guide unit. A light source device includes a light source unit. The light guide unit includes light guides that guide illumination light emitted from the light source unit to a distal end portion of the insertion part in a case where the endoscope is connected to the light source device, and a lens member that suppresses a variation in a relative intensity of each color light of the illumination light, which is emitted from the distal end portion, with respect to a light distribution angle. The lens member is disposed in the connector having stiffness.

Abstract: An endoscope includes an insertion unit, an operation unit, an emission end, a first light guide and a second light guide that guide illumination light emitted from a light source unit to the emission end, a lens member that suppresses a variation in a relative intensity of each color light of the illumination light, and a connection unit that optically connects the first light guide, the second light guide, and the lens member; and the lens member is disposed between the first light guide and the second light guide, and the connection unit and the lens member are provided in the operation unit.

Abstract: There are provided an endoscope that has sufficient air-tightness and excellent durability and an endoscope in which a reduction in the amount of light is suppressed. An endoscope includes: a light guide that emits incident light from an end portion thereof; a distal end member that is provided at the end portion of the light guide, has a function to propagate the light emitted from the light guide by total reflection, and propagates the light emitted from the light guide and emits the light from a distal end face thereof; and an imaging unit that uses the light emitted from the distal end member to image an object to be observed. The distal end member includes a light guide member made of glass.