Abstract: A light source device according to an embodiment is used with a light guide member and a wavelength converting member, and includes a light-emitting element, a light sensor, and a driving unit. The light-emitting element radiates a light beam to be incident on a first end of the light guide member by being supplied with a drive current. The light sensor detects signal light, which has been incident on a second end of the light guide member and transmitted to the first end. The driving unit supplies the drive current to the light-emitting element and controls the drive current based on a result of detection of the signal light.

Abstract: A light source device according to an embodiment is used with a light guide member and a wavelength converting member, and includes a light-emitting element, a light sensor, and a driving unit. The light-emitting element radiates a light beam to be incident on a first end of the light guide member by being supplied with a drive current. The light sensor detects signal light, which has been incident on a second end of the light guide member and transmitted to the first end. The driving unit supplies the drive current to the light-emitting element and controls the drive current based on a result of detection of the signal light.

Abstract: Infrared radiation device and production method, capable of preventing electrode degradation by heat are provided. Infrared radiation device includes substrate, insulation layer, heat generating layer, electrode, foundation portion and electric conductor. Substrate has cavity exposing part of back surface of insulation layer. Foundation portion exists on inside and outside of vertical projection area (projection direction of which is along thickness direction of insulation layer) of opening edge, on surface of substrate, of cavity. Electric conductor is provided on surface of foundation portion. End of heat generating layer is provided as cover covering electric conductor. Electrode is in contact with surface of covering outside vertical projection area. Conductor has higher melting point than that of electrode and smaller electrical resistance than those of portion and layer.

Abstract: An infrared radiation element includes: a first insulating layer having heat insulating properties and electrically insulating properties; a heating element layer provided on the first insulating layer and configured to radiate infrared radiation when energized; and a second insulating layer provided on an opposite side of the heating element layer from the first insulating layer and having heat insulating properties and electrically insulating properties. The second insulating layer transmits the infrared radiation radiated from the heating element layer. The heating element layer has such a sheet resistance that impedance of the heating element layer matches impedance of space which is in contact with the second insulating layer.

Abstract: An infrared radiation element includes: a first insulating layer having heat insulating properties and electrically insulating properties; a heating element layer provided on the first insulating layer and configured to radiate infrared radiation when energized; and a second insulating layer provided on an opposite side of the heating element layer from the first insulating layer and having heat insulating properties and electrically insulating properties. The second insulating layer transmits the infrared radiation radiated from the heating element layer. The heating element layer has such a sheet resistance that impedance of the heating element layer matches impedance of space which is in contact with the second insulating layer.