PROBLEM TO BE SOLVED: To provide a simple and compact UV light-emitting apparatus capable of stabilizing light emission output of ultraviolet light easily, a fluid concentration measuring apparatus, a dialyzer, and an ozone concentration measuring apparatus.SOLUTION: A UV light-emitting apparatus comprises: a substrate 1 having a first principal face 10 and a second principal face 11 opposed to the first principal face 10 a light-emitting part 2 disposed on the first principal face 10 of the substrate 1, and emitting ultraviolet light of 10-400 nm in wavelength and a light-receiving unit 3 disposed at a location different from that of the light-emitting part 2 on the first principal face 10 of the substrate 1. A part of UV light emitted by the light-emitting part 2 transmits through the inside of the substrate 1 and goes out from the second principal face 11 to the outside. Another part of UV light emitted by the light-emitting part 2 transmits through the inside of the substrate 1, and then goes through reflection by the second principal face 11 and enters the light-receiving unit 3. The light-receiving unit 3 performs photoelectric conversion of UV light thus received and outputs electric signals.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】簡易且つ小型で、紫外光の発光出力を容易に安定化することができる紫外光発光装置、流体濃度測定装置、透析装置及びオゾン濃度測定装置を提供する。【解決手段】第1主面10と、該第1主面10と対向する第2主面11とを有する基板1と、基板1の第1主面10上に配置されて、波長が10nm以上、400nm以下の紫外光を発光する発光部2と、基板1の第1主面10上であって、発光部2とは異なる位置に配置された受光部3とを備え、発光部2が発光する紫外光の一部は、基板1の内部を透過し第2主面11から外部へ出射し、発光部2が発光する紫外光の他の一部は、基板1の内部を透過し第2主面11で反射して受光部3に入射し、受光部3は、受光した紫外光を光電変換して電気信号を出力する。【選択図】図1
